IFW_Jahres14_04.02_Layout 1

Transcription

Annual Report 2014
2 Contents
Contents
3
Flashback to 2014
7
Facts & Figures
9
13
17
23
28
Research Area 1
Functional Quantum Materials
1.1 Exotic ground states and low-energy excitations in bulk systems
1.2 Unconventional superconductivity: Mechanisms, materials & applications
1.3 Magnetic materials for energy
1.4 Engineering magnetic microtextures
1.5 Topological states of matter
31
35
39
43
47
Research Area 2
Function through Size
2.1 Non-equilibrium phases and materials
2.2 Intelligent hybrid structures
2.3 Multifunctional inorganic nanomembranes
2.4 Nanoscale magnets
2.5 Materials for energy efficiency, storage & conversion
51
55
59
63
Research Area 3
Quantum Effects at the Nanoscale
3.1 Designed interfaces and heterostructures
3.2 Self-organised electronic order at the nanoscale
3.3 Quantum and nano-photonics
3.4 Functional molecular nanostructures and interfaces
67
71
75
79
83
104
106
108
109
110
113
115
116
Research Area 4
Towards Products
4.1 Surface acoustic waves: Concepts, materials & applications
4.2 Materials for biomedical applications
4.3 High strength materials
Leibniz Application Laboratory Amorphous Metals
4.5 Concepts and materials for superconducting applications
Appendix
Publications
Patents
PhD and diploma/master theses
Calls and awards
Scientific conferences and IFW colloquia
Guests and scholarships
Guest stays of IFW members at other institutes
Board of Trustees, Scientific Advisory Board
Research organization of IFW Dresden
Organization chart of the IFW Dresden
Flashback to 2014 3
Flashback to 2014
2014 was a crucial year for the Leibniz Institute for Solid State and Materials Research
Dresden (IFW): We underwent a serious evaluation procedure, had a change in the
scientific management at the same time, started a new research program with a complete
new structure and paved the way for a new director of one of the five IFW institutes.
The most important event was the evaluation of the Institute by the Senate of the Leibniz Association. All Leibniz Institutes are institutionally funded by the federal government and by the German Länder in equal shares. The justification of this funding has to
be affirmed for each institute in intervals of seven years by an evaluation panel set up
by the senate commission of the Leibniz Association. The prerequisite of confirmed funding is high quality scientific work and its high relevance for the whole society. A panel
of renowned, international scientists visited the institute for two days in July 2014. The
whole institute prepared very carefully for this third evaluation since the foundation of
IFW. We look quite optimistically forward to the final report that will be published by the
Leibniz Association Senate in spring 2015.
Immediately before the evaluation visit Prof. Dr. Manfred Hennecke has been appointed as temporary Scientific Director of IFW. Having been the President of Federal Institute for Materials Research and Testing (BAM) for 11 years he retired in 2013. He returned
from retirement to fill the position of the Scientific Director of IFW which was vacant
due to the request of Prof. Dr. Jürgen Eckert to be released from this office and to revert
to his role as the director of one of the five IFW institutes. One of the main task of
Professor Hennecke is to push changes in the management structure of IFW in a way that
enables for long-term stability.
Further personnel changes in the Institute’s management concern the directorship of
one of the five IFW’s institutes: the Institute for Metallic Materials which was headed by
Prof. Dr. Ludwig Schultz up to the end of September 2014. The successor in this position
is about to being appointed which will have new impact on the research program of the
whole IFW.
4 Flashback to 2014
Scientifically, 2014 was a very productive year for IFW. The appendix gives a complete
record of the publications, invited talks, patent applications, completed graduations
and theses, academic events, and guest stays. In the main part of this Annual Report
outstanding scientific results are presented according to the new structure of the IFW’s
research program which is organized into four large research areas.
쐍 Research Area 1: Functional quantum materials
쐍 Research Area 2: Function through size
쐍 Research Area 3: Quantum effects at the nanoscale
쐍 Research Area 4: Towards products
A new aspect of this program is that it consists of Research Topics that are interdisciplinary and bring closely together researchers from different IFW institutes. The creation
of such additional synergy, which strengthens the collaboration within the IFW, is one
of the main goals of this new program. In addition, the new project-oriented research
structure allows for a considerable amount of flexibility in particular for the subtopics
and will provide a dynamical framework for developing, nurturing and consolidating our
future research lines. While being distinctly multidisciplinary, there is a clear common
aspect to all activities of the IFW Dresden: all researchers at the IFW Dresden investigate
yet unexplored properties of novel materials with the aim to establish new functionalities and applications. The range of materials that are investigated in this context is broad
but well-defined. It contains Quantum Materials, a highly topical class of materials in
condensed matter physics as well as Functional Materials, representing an important part
of modern materials engineering. In the last years Nanoscale Materials, which are a
strong focus of present day materials science and a crucial material class for cutting-edge
developments in electrical engineering, came in the fore of our research in several IFW
institutes. These three classes, Quantum Materials, Functional Materials and Nanoscale
Materials, provide the three materials-oriented pillars of the IFW. Each of these three new
research areas, connecting two different classes of materials, follows the motto of the
Leibniz Association “theoria cum praxi”: They consist of well-defined research topics
connecting basic science with applied research and bring together researchers from all
five IFW institutes. The research area “Towards products” binds together materials
science and engineering that is at the borderline to prototypes or products. Establishing, fostering and promoting the contact to industry partners is the main aspect
within this activity.
Inauguration ceremony of the new annex building
of IFW in February 2014
Flashback to 2014 5
Prizes and Awards for IFW members:
Tschirnhaus Medal for the best PhD theses (left),
IFW Research Prize for Dr. Sabind Wurmehl (middle),
Prize of the German Copper Institute for
Dr. Alexander Kauffmann (right)
As a Leibniz Institute the IFW is budgeted by the federal government and the German
federal states in equal parts. However, a considerable extension of capability is the
amount of third party project funding which is also an important index of quality. The
level of third party funding in 2014 amounts to 11.874 Mio. Euro – a level at the forefront
of the Leibniz Association. Most of this project funding was acquired in a highly competitive mode from the DFG and the EU. In particular the grant of the new Collaborative
Research Centre 1143 on “Correlated magnetism: From frustration to topology” where
the IFW is collaborating with the TU Dresden shows the competitive capability of the IFW.
Among the large number of third party funded projects are three DFG-Priority Programs
that are coordinated by the IFW, further eight DFG-Priority Programs where the IFW
participates, as well as three DFG Research Groups where the IFW participates. As in the
previous years the IFW has been very successful in initiating EU projects and participating in them. Though quite time consuming these project applications have very positive
effects on networking the IFW with other European groups. 9 of our 16 EU projects running in 2014 have been coordinated by the IFW.
Essentially publicly funded, the IFW is obliged to make its research results public. About
380 publications in scientific journals and conference proceedings report on the IFW’s
research results on the year 2014. In almost 200 invited talks the Institute’s scientists
presented their work at other places around the world. 19 patents were issued for the IFW,
and applications for 16 more patents have been made. Apart from these scientific communications the IFW continued its large efforts to make scientific work accessible for the
general public and to inspire young people to study science or engineering. The IFW took
part in many joint actions like the lecture series “Physics on Saturday”, “Junior Doctor”
or the Summer University of the TU Dresden. Besides these big events we organize almost
weekly lab-tours for various visitor groups, from school classes through official representatives to guests from foreign organizations. Especially the IFW’s superconducting test
facility SpuraTrans in Dresden-Niedersedlitz has proved very popular among visitors, be
it representatives from companies, students groups or politicians.
With respect to the infrastructural development we have put large efforts during the last
years into the realization of a new annex building with special laboratory areas and
additional office space. In beginning of 2014 construction works were completed and
we celebrated the inauguration of the annex building. Right in between the old and the
new parts of the building a nice atrium was created which already have proved very
useful for various events.
6 Flashback to 2014
2014 was again a yielding year with respect to prizes and honors awarded to members
of the IFW. Among them are the International Dresden Barkhausen Award for Prof. Dr.
Oliver G. Schmidt and the DGM Prize for Prof. Dr. Jürgen Eckert. Dr.-Ing. Alexander Kauffmann was awarded two prizes for his outstanding PhD thesis: the DGM Junior Award and
the Prize of the German Copper Institute. The most prominent prize for an IFW member
surely was the German Federal Cross of Merit (first class) for Prof. Dr. Manfred Hennecke,
although it was not related to his activities at our Institute. A full list of prizes awarded
to members of the IFW is included in the appendix.
Furthermore, three scientists of the IFW have been offered a chair at universities in 2014:
Dr. Maria Daghofer accepted a call to the University of Stuttgart and Prof. Dr. Jürgen
Ecker t is negotiating with University Leoben (Austria) and Dr. Jochen Geck with the
University of Salzburg (Austria).
A crucial part of the IFW’s identity is its vivid life including the cultivation of the scientific dialogue, family-friendly working conditions, intercultural diversity and the support
of sportive and cultural activities. In 2014 the IFW organized a series of workshops,
colloquia and talks to foster the scientific dialogue and, along the way, allow for social
and communication aspects of cooperation. An important meeting for all scientists of
the IFW was the two-day program meeting where all scientists discussed and adjusted
the research program for the following year. Social events like the annual IFW Summer
Day, the Christmas party and vernissages to our art exhibitions also contribute to a good
working atmosphere among all IFW groups.
The positive development of the IFW is being fostered continuously by the engagement
of colleagues and partners from universities, research institutes and industry, our
Scientific Advisory Board and the Board of Trustees as well as the funding organizations. This holds true especially when the institute experiences turbulent times. We would
like to thank all our partners and friends for their support and cooperation.
Active in scientific communication on conferences,
workshops and fairs.
Facts & Figures 7
Facts & Figures
Organization
The Leibniz Institute for Solid State and Material Research Dresden (IFW) is one of
currently 89 institutes of the Leibniz Association in Germany. It is a legally independent
association, headed by the Scientific Director, Prof. Dr. Manfred Hennecke, and the
Administrative Director, Hon.-Prof. Dr. h. c. Rolf Pfrengle.
The scientific body of the IFW Dresden is structured into five institutes, the directors of
which are simultaneously full professors at Dresden, respectively Chemnitz Universities
of Technology:
쐍 Institute for Solid State Research, Prof. Dr. Bernd Büchner
쐍 Institute for Metallic Materials, Prof. Dr. Rudolf Schäfer (temporarily)
쐍 Institute for Complex Materials, Prof. Dr. Jürgen Eckert
쐍 Institute for Integrative Nanosciences, Prof. Dr. Oliver G. Schmidt
쐍 Institute for Theoretical Solid State Physics, Prof. Dr. Jeroen van den Brink
Further divisions are the Research Technology Division and the Administrative Division.
Financing
The IFW receives an institutional funding of 50% from the Federal Government of Germany and the Länder Governments each. In 2014, this funding was about 30,587 million
euros.
In addition, there was a total of third party funding in 2014 of about 11,874 million
euros. From that, about 37% were funded by the DFG, 31% by EU projects, 12% by
Federal Government projects, 10% by industry projects and 10% by other projects and
projects funded by the Free State of Saxony.
8 Facts & Figures
Personnel
On December 31, 2014, 506 staff members were employed at the IFW, including 114 doctorate students and in addition 22 apprentices in seven different vocational trainings.
Furthermore, there was a total of 145 guest scientists and 15 diploma students working
at the IFW in 2014.
Gender equality, as well as work life balance, are defined goals of the IFW Dresden. In
2014, the percentage of women in scientific positions was 34% and the percentage of
women in scientific leading positions was 31 %. In 2007, the IFW qualified for the
certificate “audit berufundfamilie” (a strategic management tool for a better compatibility of family and career) and was already re-audited two more times.
Vocational training has always been an important activity of the IFW. At present, apprenticeships are available for seven professions. On annual average, around 25 trainees complete an apprenticeship at the IFW. In 2014, the IFW was awarded the prize “Excellent
Training Company” by the German Chambers of Commerce and Industry and the institute’s apprentices received awards for their excellent performance during their training.
A female physics lab technician apprentice was even nominated for the Apprenticeship
Price 2014 of the Leibniz Association and achieved second place in the end. From 2012
until 2014, the IFW’s Administrative Director was the Executive Board Representative of
the Dual Vocational Education and Training of the Leibniz Association.
Number of publications and patents
In terms of publications, the qualitative and quantitative level remains high at the IFW.
In 2014, there were altogether 336 publications quoted by Web of science. By December 31, 2014, the IFW holds 143 patents in Germany and 155 international patents.
Research Area 1 FUNCTIONAL QUANTUM MATERIALS 9
Research Topic 1.1
Exotic Ground States and low-energy excitation in bulk systems
People: M. Abdel-Hafiez, A. Alfonsov, S.-H. Baek, S. Bahr, M. Belesi, V. Bisogni, E. M. Brüning, M. Daghofer, T. Dey,
S.-L. Drechsler, J. Geck, H. J. Grafe, F. Hammerath, C. Hess, N. Hlubek, L. Hozoi, H. Kandpal, V. Kataev, V. M. Katukuri,
S. Kourtis, R. Kraus, A. O. Leonov, A. Maljuk, A. Mohan, S. Nishimoto, J. Romhanyi, U. K. Rössler, K. Roszeitis,
I. Rousochatzakis, M. Schäpers, W. Schottenhamel, C. Sekar, H. Stummer, Y. Utz, A. Wolter, S. Wurmehl
Responsible Directors: B. Büchner, J. van den Brink
Summary: In this research topic we investigate both experimentally and theoretically a broad class of complex transition metal oxides such as cuprates, cobaltites, iridates
and pyrochlore compounds, where quantum spin fluctuations, strong magnetic frustration effects and spin-orbit coupling give rise to unconventional quantum ground
states and exotic spin excitations. Our research benefits a lot from a unique combination of different, mutually complementary methods that is available at the IFW
Dresden, including expertise in both theory and experiment. In this article we review
our work in 2014, which enabled us to obtain a number of interesting new fundamental insights into the magnetism of correlated quantum matter.
Complex transition metal (TM) oxides provide a rich playground for studies of fundamental models of quantum magnetism. In particular, in certain crystal lattices chemical
bonds mediate strong magnetic exchange coupling between the spins of TM ions only in
one (1D) or two (2D) spatial directions giving rise to low-dimensional spin networks in
form of chains, ladders and planes. The spin chains in the 3d cuprates are considered as
almost ideal realizations of the celebrated 1D spin-1/2 isotropic Heisenberg antiferromagnetic model (HAFM), since the Cu2+ ion carries a small quantum spin-1/2 and the
orbital momentum is quenched.
One focus of our research has been on the elementary excitations of a quantum spin-1/2
chain, the spinons. In our combined theoretical and experimental approach, taking spinon excitations in the quantum antiferromagnet CaCu2O3 as an example, we demonstrate
that femtosecond dynamics of magnetic electronic excitations can be probed by direct
resonant inelastic x-ray scattering (RIXS) [1]. To this end, we isolate the contributions
of single and double spin-flip excitations in experimental RIXS spectra, identify the
10 Research Area 1 FUNCTIONAL QUANTUM MATERIALS
Fig. 1: (a) Initial state, just before the creation of the
core hole. (b) Intermediate state with one doublon
and one core-hole present right after the creation of
the core hole. As the 3d level at the core-hole site has
a net spin of 0, the magnetic coupling to neighboring
sites vanishes. (c) Intermediate state just before the
de-excitation of the core-hole. Left: two spins next
to the core-hole site have flipped due to scattering
on the doubly occupied site. Right: the spin-orbit
coupling of the 2p state has flipped the core-hole
spin. (d) Two-spinon excitations with ΔS = 0 (left)
and ΔS = 1 (right) present in the final state.
physical mechanisms that cause them, and determine their respective time scales
(Fig.1). By comparing theory and experiment, we find that double spin flips need a finite amount of time to be generated, rendering them sensitive to the core-hole lifetime,
whereas single spin flips are, to a very good approximation, independent of it. This shows
that RIXS can grant access to time-domain dynamics of excitations and illustrates how
RIXS experiments can distinguish between excitations in correlated electron systems
based on their different time dependence.
In the 1D spin-1/2 HAFM the spinons can be excited by an infinitesimally small energy,
i.e., excitations are gapless. However, perturbations of the spin chain, such as modulation of the exchange coupling along the chain, may radically alter the spin excitation
spectrum. We have shown this experimentally by measuring the longitudinal 63Cu nuclear
spin relaxation rate T1-1 in the model spin-1/2 chain cuprate Sr1.9Ca 0.1CuO3 [2]. Owing
to the on-site hyperfine coupling, the nuclear spin sensitively probes the Cu electron spin
dynamics. We observe a surprising exponential drop of the rate T1-1 below ∼ 100 K
which signals an opening of a pseudogap in the spin excitation spectrum, i.e., a substantial suppression of spinon excitations at low energies (Fig. 2). We attribute this drastic
effect to the off-chain partial substitution of Sr by Ca which causes Cu-O bond disorder
and consequently a small random alteration of the intrachain exchange coupling.
Furthermore, we can show that such bond disorder has a strong impact on the propagation of the spinons along the chain. By measuring the magnetic heat conductivity in
single crystals of (Sr1-x Cax )2CuO3 we have found that the spinon mean-free path is very
sensitive to even slight bond disorder and reduces from >1300 lattice spacings in the
clean material (x = 0) to very short ∼12 lattice spacings for large Ca dopings [3].
Frustration effects arising in the 1D spin-1/2 HAFM due to AFM next-nearest neighbor
interactions have been studied for the Cu chains in linarite PbCuSO4(OH)2 . Indeed we observed unusual magnetically ordered states such as helical structures together with a rich
phase diagram along the Cu chain direction [4,5]. Using DMRG and TMRG approaches we
demonstrated that a significant symmetric anisotropic exchange is necessary to account
for the basic experimental observations, which in turn might stabilize a triatic (threemagnon) multipolar phase [4].
Fig. 2: The 63Cu nuclear relaxation rate T1-1
decreases strongly below ~ 100 K due to the opening of a pseudogap in the spin excitation spectrum
of Sr 1.9 Ca 0.1CuO3.
Squares and closed circles correspond to measurements along the crystallographic b- and a-axis,
respectively, and open circles denote our earlier
data on the spin-chain compound Sr0.9Ca 0.1O2
shown here for comparison [see, F. Hammerath et
al., Phys. Rev. Lett. 107, 017203 (2011)]. The inset
shows the temperature evolution of the stretching
exponent γ of the nuclear magnetization decay.
Though long-range magnetic order in 1D spin-1/2 HAFM’s is not possible even at T = 0
due to quantum fluctuations, in real materials residual interchain couplings often induce
magnetic order at finite temperatures. We have examined one specific case of the
competing interchain couplings corresponding to the so-called Nersesyan-Tsvelik
model in the spin-1/2 chain compound (NO)[Cu(NO3)3] [6]. Interestingly, our specific
heat, neutron scattering and muon spin rotation data reveal that frustration of the interchain exchange yields incommensurate magnetic order at TN = 0.58 K, much smaller
than the intrachain exchange J ∼ 140 K. A somewhat similar effect of frustration, also
yielding a suppressed and incommensurate magnetic order, we have found by measuring nuclear magnetic resonance in a system with larger spin value and dimensionality,
namely the non-olivine LiCoPO4 [7].
The nature and the role of longer-range exchange couplings has been also explored by
joint high-field electron spin resonance (HF-ESR) measurements and theoretical analysis in the 3D Cu oxide compound Cu2OSeO3 [8,9], a Mott insulator recently shown to harbor skyrmion physics. An effective model of coupled ferrimagnetic Cu tetrahedra has been
derived by using exchange couplings obtained from electronic-structure computations
and modeling of the HF-ESR data. It has allowed us to calculate the fundamental magnetic properties of this complex ferrimagnet, including the pitch length of the
Dzyaloshinskii spiral ground state, in very good agreement with recent experiments. Additionally, a number of new predictions have been made [8]. In particular, the effective
sublattices of Cu tetrahedra should display weak AF canting within each unit cell; near
the ordering temperature, the magnetic phase diagram will embody a skyrmionic phase
as condensates of partial skyrmions with defects in zero or low magnetic fields and a
densely packed array of integer skyrmions stratified by larger applied fields.
Besides 3d TM oxides, recently the 5d iridates have attracted considerable attention due
to predictions of novel magnetic phenomena driven by strong spin-orbit coupling. In particular, the orbital momentum of Ir 4+ is unquenched, which should lead to strongly
anisotropic magnetic interactions. By HF-ESR we have studied the low-energy spin
dynamics in a single crystal of Sr2 IrO4, the prototype 2D spin-orbital Mott insulator. By
measuring the frequency dependence of the AF resonance modes we have found a surprisingly small energy gap for magnetic excitations, amounting to only 0.83 meV [10].
This suggests rather isotropic Heisenberg dynamics of the interacting Ir 4+ effective
spins, despite the spin-orbital entanglement in the ground state. The anomalous order
of the Ir t2g levels in Sr2 IrO4 , evidenced by the structure of the g tensor [10], is confirmed
by electronic-structure calculations [11] and apparently related to low-symmetry potentials involving atomic sites beyond the nearest-neighbor O cage. The sizable Ir t2g
splittings are also reflected in RIXS, e.g., in the two-peak structure of the j = 3/2-like
spin-orbital exciton. By a detailed analysis, we have further shown that this chargeneutral excitation is dressed with magnons and propagates with the canonical characteristics of a quasiparticle that mirrors the one-hole propagation in the spin-1/2 background of 2D cuprate superconductors [12]. Valuable insights into the precise structure
and the magnitude of the magnetic couplings, both isotropic and anisotropic, comes from
many-body quantum chemistry calculations – while in the 2D square-lattice 5d 5 iridate
Ba2 IrO4 a Heisenberg-compass type of model is realized [13], the dominant interaction
in 2D honeycomb systems such as Na2IrO3 is the Kitaev exchange, which further turns
out to be ferromagnetic from the ab intio computations [14]. Joint RIXS measurements
and theoretical investigations have also allowed to clarify the evolution of the magnetic excitation spectrum of Sr2IrO4 as function of strain [15].
Regarding the material synthesis and crystal growth, where we apply different methods
ranging from flux methods (e.g., for iridates) and high pressure synthesis in the GPa
regime to the travelling solvent floating zone using optical heating, we have succeeded to grow high quality single crystals of LaCuO2 [16] and Li(Mn,Ni)PO4 [17] which are
now available for magnetic studies within this research topic.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
V. Bisogni et al., Phys. Rev. Lett. 112, 147401 (2014)
F. Hammerath et al., Phys. Rev. B 89, 184410 (2014)
A. Mohan et al., Phys. Rev. B 89, 104302 (2014)
M. Schäpers et al., Phys. Rev. B 88, 184410 (Nov. 2013)
M. Schäpers et al., Phys. Rev. B 90, 224417 (2014)
C. Balz et al., Phys. Rev. B 90, 060409(R) (2014)
S.-H. Baek et al., Phys. Rev. B 89, 134424 (2014)
O. Janson et al., Nature Commun. 5, 5376 (2014)
M. Ozerov et al., Phys. Rev. Lett. 113, 157205 (2014)
S. Bahr et al., Phys. Rev. B 89, 180401(R) (2014)
V. M. Katukuri et al., Inorg. Chem. 53, 4833 (2014)
J. Kim et al., Nature Commun. 5, 4453 (2014)
V. M. Katukuri et al., Phys. Rev. X 4, 021051 (2014)
V. M. Katukuri et al., New. J. Phys. 16, 013056 (2014)
A. Lupascu et al., Phys. Rev. Lett. 112, 147201 (2014)
A. Mohan et al., J. Cryst. Growth 402, 304 (2014)
K. Wang et al., J. Cryst. Growth 386, 16 (2014).
Funding: DFG
Cooperation: MPI-CPfS Dresden, MPI-PKS Dresden, TU Dresden, Helmholtz-Zentrum
Dresden-Rossendorf, MPI-FKF Stuttgart, Helmholz-Zentrum Berlin, University
Heidelberg, TU Berlin, TU Braunschweig, University Magdeburg, ILL Grenoble, ANSTO
Australia, University Paris-Sud, University Pavia, University Tokyo, Argonne National
Laboratory, PSI Villigen, ISIS, Politecnico di Milano, Moscow State University,
University of Toronto, University of California Irvine, University of Crete, IISER, Pune,
India
Research Topic 1.2
Unconventional superconductivity:
Mechanisms, materials & applications
People: S. Aswartham, S.-H. Baek, D. Baumann, R. Beck, S. Borisenko, Dai-Ning Cho, S. L. Drechsler, D. Efremov,
D. Evtushinsky, G. Fuchs, R. Ganesh, J. Geck, M. Gillig, A. Wolter-Giraud, H. J. Grafe, V. Grinenko, D. Gruner,
M. Abdel Hafiez, L. Harnagea, C. Hess, B. Holzapfel, R. Hühne, K. Iida, R. Kappenberger, S. Khim, K. Koepernik,
T. Kühne, M. Kumar, F. Kurth, Zhonghao Liu, S. Luther, I. Morozov, P. K. Nag, K. Nenkov, S. Richter, M. Scheffler,
W. Schottenhamel, M. Schulze, S. J. Singh, F. Steckel, S. Sykora, J. Trinckauf, S. Wurmehl, C. Wuttke, F. Yuan
Responsible Directors: B. Büchner, L. Schultz, J. van den Brink
Summary: Superconductivity as a quantum phenomenon represents one of the most
fundamental problems of condensed matter physics. In spite of the long history of
research there are still many new findings and open questions. Nowadays the so called
unconventional superconductors are in the focus of the condensed matter community, since these materials demonstrate the highest superconducting critical temperature. In order to improve application and to find new compounds, we try to understand
the nature and the key features of the emergent superconductors by means of systematic studies, both experimental and theoretical.
The following specific aspects of unconventional superconductivity are at the focus of our
research:
쐍 Symmetry and structure of the superconducting and competing order parameters
쐍 Nature of the pairing mediator
쐍 Competing/coexisting ground states, quantum criticality
쐍 Pseudogap, various density waves, nematic order
쐍 Disorder induced effects
Our research efforts seek to obtain systematic and quantitative information by applying
modern experimental methods supplemented by subsequent theoretical treatment. To
obtain the most precise information we use several complementary experimental techniques for the same samples. More specifically, in the experiments we use spatially and
momentum resolved spectroscopies, thermodynamics, transport, magnetic resonance
as well as phase-sensitive techniques applied together to the wide range of the singlecrystalline bulk and in-situ grown thin film and heterostructured materials, such as
iron-based pnictides and chalcogenides, cuprates, heavy fermion systems, ruthenates,
and elemental superconductors. In theory we use a set of techniques to describe the
electronic structure of superconducting materials among which are various types of
Renormalization Group methods, diagramatic Green function methods, multiband Eliashberg theory and Density Functional Theory.
Our current work on the nematic order in FeSe [1] may illustrate the field of our research.
It concerns one of the important aspects of all unconventional superconductors: in these
materials superconductivity emerges in the vicinity to other instabilities. Therefore the
understanding which of the degrees of freedom, spin, orbital or lattice, drives these
instabilities, gives the answer what is the glue of superconducting cooper pairing. Most
of the parent compounds of the novel iron-based superconductors exhibit magnetic
spin-density wave ordering as a ground state. But the magnetic transition is preceded
or coincides with the tetragonal to orthorhombic structural transition. The state in
between these two transitions, which is characterized by a broken C 4 symmetry while
time-reversal symmetry is still preserved, is called nematic.
Previously, good arguments have been put forth which rule out lattice distortions as a
driving mechanism for the structural transition. Therefore it was proposed that strong
spin fluctuations may lead to the nematic order. Moreover there is experimental evidence
of an increase of 1/(T1T ) in NMR experiments near the structural transition. However,
the closeness of the two transitions (structural and magnetic) impeded an unambiguous answer to the question which degree of freedom is responsible for the structural
transition.
FeSe is a unique material in that it shows only a structural but no magnetic transition
and hence lends itself to the investigation of the genuine nematic phase. In FeSe, a
tetragonal to orthorhombic symmetry reduction occurs at Tnem = 91 K, which is to be
connected with a nematic instability. We measured NMR spectra of 77Se, having nuclear
spin 1/2, as a function of temperature in an external magnetic field H = 9 T.
Below Tnem we observe a splitting of the 77Se lines for H||a into two lines l 1 and l 2 in
contrast to the absence of a splitting for the H||c line l 3, which hints to an in-plane
symmetr y change as shown in Fig.1a depicting the temperature dependence of the
Knight shift K. Now we discuss the possible origin of the splitting. It can be excluded that
the orthorhombic lattice distortions cause the line splitting K 1 -K 2 due to a significant
change of this splitting when the superconducting state is entered at Tc = 9.3K, where
the lattice structure does not change notably. The in-plane orthorhombic distortion is
much smaller than the a,c structural anisotropy of the layered lattice structure, while
the size of K 1 -K 2 below Tnem is of comparable size to the line splitting K 3 -K 1,2 above Tnem.
This is incompatible with the orthorhombic distortion being the origin of the large
splitting K 1 - K 2. The averaged K 1 and K 2 signal has the same temperature dependence
as K3 over the whole temperature range, while the difference Knight shift splitting
ΔK||a = (K 2 - K 1)/2 between l 1 and l 2 exhibits a typical √(Tnem - T ) temperature behavior
of a Landau-type order parameter close to a second-order phase transition. In order
to exclude spin degrees of freedom as cause of the observed in-plane line splitting we
measured the spin-lattice relaxation rate as a function of temperature. The quantity
1/(T1T ) probes the dynamical susceptibility and hence the antiferromagnetic spin fluctuations. However crossing the nematic phase transition it barely changes, indicating
no enhancement of spin fluctuation and putting the system far away from a magnetic
instability. Only when approaching the superconducting transition we find a significant
(a)
(b)
(c)
Fig. 1: Emergence of orbital-driven nematic state in FeSe. a, Temperature dependence of the
77
Se Knight shift K for fields ||a and ||c. Whereas at Tnem, K ||a splits into lines l 1 and l 2, both K ||c
and the averaged position of l 1 and l 2, show a smooth T-dependence. b, Temperature dependence of the l 1 - l 2 line splitting below Tnem in terms of the difference ΔK ||a. Inset: below Tnem the
splitting is proportional to √(Tnem -T ), as expected for an order parameter at a second-order
phase transition. c, Top view of the FOO in FeSe with two different domains that are present in
a twinned crystal. The double headed arrow indicates the nematic order parameter.
enhancement, which is evidence that spin fluctuations are not driving the nematic
transition. Furthermore, the extremely narrow NRM lines well below Tc indicate the
complete absence of static magnetism.
This leaves orbital degrees of freedom and in particular ferro-orbital order (FOO) as
driver for the nematic transition. Theoretical analysis of the free energy in the vicinity
of the ferro-orbital ordering transition in the presence of a magnetic field allows to
derive a direct proportionality of the order parameter ψ to the anisotropy in the magnetic susceptibility χ xx - χ yy ∝ ψ ∝ √(TOO - T ). An analysis of the hyperfine constants
establishes that its anisotropy and hence the anisotropy of the Knight shift difference
are proportional to the orbital order parameter ψ: ΔK ||a ∝ √(TOO - T ) while the averaged
in-plane and the out-of-plane Knight shift depend on ψ only in higher order. Clearly
the measured splitting ΔK ||a shows a square root behavior close to the nematic transition (Fig. 1b), so that we conclude Tnem =TOO. NMR does not give information about the
orientation of the Fe 3dyz and 3d xz orbitals with respect to the in-plane lattice vectors
a and b. However, the orthorhombic distortion induced by the FOO ordering implies an
alignment of the main axis of χ with the lattice vectors: x||a and y||b, which leads to an
FOO pattern aligned along either of the two in-plane axis depending on the actual
domain in our twinned crystal (Fig. 1c).
The resulting inequivalence of the a and b directions then naturally leads to the observed
line splitting. A measurement of the NMR signal with the magnetic field along the [110]
direction indeed does not lead to a splitting between l 1 and l 2 in the orthorhombic state
below Tnem , which is another clear prove that the tetragonal symmetry is broken below
Tnem. Finally, the significant change of the Knight shift splitting ΔK ||a below TC indicates
that superconductivity and nematicy are competing orders - superconductivity tends to
suppress orbital ordering and vice versa.
For a more complete overview of our research during 2014 we refer the reader to our
published articles, a selection of which is given in the Reference Section.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
S-H. Baek et al. Nature Materials (2014), doi:10.1038/nmat4138.
K. Iida et al., APL 105, 172602 (2014).
D. Daghero et al., Applied Surface Science 312, 23 (2014).
R. Sobota et al., Applied Surface Science 312, 182–187 (2014).
R. Ganesh et al., Phys. Rev. Lett. 113, 177001(2014).
V. Grinenko et al., Phys. Rev. B 89, 060504(R) (2014).
A. Reifenberger et al., J. Low Temp. Phys., 175, 755 (2014).
V. Grinenko et al., Phys. Rev. B 90, 094511 (2014).
Yu.G. Naidyuk et al., Phys. Rev. B 89, 104512 (2014).
M.M. Korshunov et al., Phys. Rev. B 90, 134517 (2014).
S. Johnston et al., Phys. Rev. B 89, 134507 (2014).
H.-J. Grafe et al., Phys. Rev. B 90, 094519 (2014).
S. Ziemak et al., Supercond. Sci. Technol. 28, 014004 (2015).
F. Ahn et al., Phys. Rev. B 89, 144513 (2014).
D. V. Evtushinsky et al., Phys. Rev. B 89, 064514 (2014).
T. Saito et al., Phys. Rev. B 90, 035102 (2014).
E. Stilp et al., Sci. Reports 4, 6250 (2014).
J. Maletz et al., PRB 89, 220506 (R) (2014).
Funding: DFG (SPP1458, GRK1621), BMBF (ERA.Net Rus project),
EU (SuperIron, IronSea)
Cooperation: Moscow state university; Pohang University, Korea; CNRS CRISMAT;
IISER, Pune; University of Cologne; Helmholtz-Zentrum Berlin; University of Heidelberg; University of Erlangen-Nürnberg; University of Greifswald; Goethe University,
Frankfurt am Main; WMI Munich; TU Dresden; PSI, Switzerland; University of Pavia,
Italy; Universit’a degli Studi dell’Aquila, Italy; University of California, Davis;
University of British Columbia, Vancouver, Canada; Max Planck Institute for Solid
State Physics, Stuttgart; University of Twente, Netherlands; B. Verkin Institute for Low
Temperature Physics and Engineering, Kharkiv, Ukraine; Technical University Graz,
Austria; Max-Planck Institute for Chemical Physics of Solids, Dresden; Kirensky Institute of Physics, Krasnoyarsk, Russia; Çukurova University, Turkey; CNR-SPIN Genoa,
Italy; University Nagoya, Japan; NHMFL Tallahassee, USA; Helmholtz-Zentrum
Dresden-Rossendorf, Germany
Research Topic 1.3
Magnetic materials for energy
People: V. Alexandrakis4, A. Backen, A. Bauer1, C. G. F. Blum, A. Edström7, S. Fähler, P. Fajfar9, C. Favero10, A. Funk,
G. Giannopoulos6, S. Gottlieb-Schönmeyer1, T. Gottschall8, O. Gutfleisch8, Ch. Haberstroh16, S. Hamann4, O. Heczko3,
R. Heller5, R. Hermann, C. Hess, M. Hoffmann, G. Hrkac14, A. Kato15, S. Kauffmann-Weiss, A. Kitanovski9, M. Kohl12,
J. Kopecek 3, M. Kopte, M. Krautz, B. Krevet 12, J. Kuneš 3, D. Lindackers, A. Ludwig4, L. Manosa11, M. Meven2, O. Mityashkin,
J. D. Moore, V. Neu, D. Niarchos6, R. Niemann, S. Oswald, B. Pedersen2, C. Pfleiderer1, A. Planes11, A. Poredoš 9, D. Pohl,
B. Pulko9, Q.M. Ramasse13, A. Regnat1, L. Reichel, M. Richter, S. Rodan, J. Romberg, J. Rusz 7, S. Sawatzki 8, M. Schmitt12,
T. Shoji15, A. Siegel4, K.P. Skokov8, F. Steckel, J. Tušek9, E. Vives11, A. Waske, B. Weise, T. G. Woodcock, S. Wurmehl, M. Yano15
Responsible Directors: B. Büchner, J. Eckert, L. Schultz, J. van den Brink
Summary: Our investigations on magnetic materials for energy-related applications are
illustrated by several examples, which span the range from (i) fundamental research
on single crystals (Mn3Si), where bulk thermodynamic and transport measurements
were performed to elucidate the origin of electronic ordering phenomena, over (ii) the
search for new material compositions of bulk-like (Fe-Co-X) films and rare-earth-lean
Sm-Co/Fe multilayers with a large magnetic anisotropy, (iii) the preparation of
magneto-caloric (La-Fe-Si) composite materials with a wear close to application
requirements, and (iv) studies of the micro-structural dynamics of magnetic shapememory alloys (Ni-Mn-Ga) to (v) resolving the real structure of commercially used
materials (Nd-Fe-B) at the atomic level. Related goals are (i + ii) the identification of
new material compositions with potentially application-relevant properties; (iii + iv)
the detailed understanding and tuning of known material classes toward specific
applications; and (v) the optimization of applied materials.
(i) Spin density wave order and fluctuations in Mn3Si
In many systems, there is an intimate connection between electronic ordering phenomena and unconventional superconductivity. A prime and recent example represents
the class of Fe-pnictides where the suppression of the spin density wave (SDW) leads to
the emergence of superconductivity. Hence, itinerant antiferromagnetic intermetallic
compounds with a SDW transition may be seen as model systems for advancing the
Fig. 1: (a) Specific heat, (b) resistivity of Mn3Si.
Inset (a): construction of TN. Inset (b): resistivity
of LaFeAsO [1].
understanding of such electronic ordering phenomena with Mn3Si being an example
in the class of Heusler compounds (TN = 21 K) [1] and CrB2 a representative with an
hexagonal structure similar to MgB2 (TN = 88 K) [2].
We have studied the specific heat, electrical resistivity (Fig. 1), thermal conductivity, Hall
effect, Seebeck effect, and Nernst effect of a Mn3Si single crystal in the temperature
range from 10 K up to 300 K [1]. Clear anomalies are observed at the SDW transition in
all transport coefficients. These anomalies originate in both strongly temperaturedependent changes of the relaxation time and of the Fermi-surface topology in response
to the SDW transition. Moreover, we find strong evidence for a large fluctuation regime
which extends up to ∼ 200 K in the resistivity, as well as in the Seebeck and Nernst
effects. This extended fluctuation regime may be interpreted as the signature of competing orders in Mn3Si. A comparison of our results on Mn3Si with other prototype SDW
materials, viz., the iron arsenide LaFeAsO and the classical SDW prototype chromium
reveals a generic manifestation of the SDW in transport coefficients.
(ii) Rare-earth-free and rare-earth-lean films
with a large magnetic anisotropy
As an alternative approach to obtain rare-earth free permanent magnets we explore the
suitability of Fe-Co-X films which are strained in order to induce magnetocrystalline
anisotropy. For a systematic search by combinatorial methods together with RU Bochum
a composition spread of epitaxial Cu-Au was examined, which allows for a large variation of in-plane lattice parameters [3]. While this approach aims to induce strain by
coherent epitaxial growth, which is limited to film thicknesses of a few nm [4], the use
of additional Carbon induces a spontaneous strain [5]. With this also thick films can be
prepared, which reach a magnetocrystalline anisotropy up to 0.4 MJ/m3.
Making use of the unprecedented magnetocrystalline anisotropy of the hexagonal
SmCo5 phase in epitaxial nanoscaled Sm-Co/Fe multilayer heterostructures allows the
realization of record energy densities (BH)max > 450 kJ/m3 in a rare-earth-lean magnet.
Figure 2 shows the dependence of (BH)max on the individual layer thicknesses and
multilayer architecture in SmCo5 /[Fe/SmCo5]n , with n = 1 (3-layer sample) and n = 2
(5-layer sample).
Fig. 2: Energy density (BH) max of 3-layer and
5-layer Sm-Co/Fe samples as a function of
Fe-volume fraction.
(iii) Magneto-caloric composites
Magneto-caloric La(Fe,Si)13 is usually very brittle and requires the combination with
another material in order to form a regenerator that will survive millions of cycles in a
magneto-caloric cooling device. At IFW, a novel magneto-caloric composite based on
La(Fe,Si)13 particles in an amorphous metallic matrix has been studied [6], see Fig. 3.
Magneto-caloric particles and a powderized Pd-based glass were hot-compacted at the
glass transition temperature, Tg, of the metallic matrix. At this temperature, the viscous
matrix can easily fill the pores between the La(Fe,Si)13 particles, thereby creating a dense
composite. Furthermore, the matrix acts as a buffer during the hot-compaction and
prevents crack formation in the magneto-caloric particles, which is otherwise known to
reduce their performance. Tuning our processing route, the magneto-caloric properties
of the composites are almost independent of the compaction pressure.
Another possibility to form magneto-caloric composites is to combine La(Fe,Si)13-based
Fig. 3: Hot compaction of a La(Fe,Si)13 -based
composite at Tg of the amorphous component.
particles of various size fractions with a polymer matrix [7]. Such composites were
pressed into thin plates of about 200 mm thickness, a geometry favorable for the subsequent testing of the composites in an
active magnetic regenerator (AMR). We
found that a higher filling factor which
can be achieved by using a mixture of
several particle size fractions has beneficial influence not only on the magneto-caloric properties, but also on the
thermal conductivity. Tests in the AMR
revealed that a maximum temperature
span of approximately ΔT = 10 K under a
magnetic field change of μ0 H = 1.15 T
can be obtained without cooling load.
The stability of the measured ΔT values
and the mechanical integrity of the
sample after cyclic application of a
magnetic field have been monitored for
90,000 cycles and showed very good
stability of the magneto-caloric performance.
MagKal - a good-practice-project of technology transfer
Based on the magnetocaloric effect (MCE) the efficiencies of cooling devices and heat
pumps might be notably improved. Estimates of about 40 % reduction in electricity
consumption are tempting the industries to get early access to this new technology and
to have it ready for the market launch. Keeping industrial and household applications
in mind, each new technology has to compete with the established compressor cycle.
Continuously improved during the last century the marked is almost flooded with cheap
refrigerators and heat pumps providing sufficient temperature span, thermal power and
reliable operation for decades. Considering this starting point most of the research activities in the fields of magnetocalorics have to be rated concerning their contribution
to further applications. The literal meaning is that materials, showing a sufficient MCE
have to be at the same time mechanically stable, have to resist corrosion, and have to
be available worldwide in big quantities and for low costs. Concurrently the machinery
around the MCE materials has to provide efficient heat transfer into the thermal process
by requiring minimal quantities of magnetic materials and less electricity than a cooling compressor. From the existing state of knowledge these challenging targets cannot
be met at once. A screening process, investigating the various options of building a MCEmachine, was started in 2012 with the project “MagKal”, aiming to build an operating
MCE-machine. Beyond the technical issues the market potentials of the technology
should be gauged as well, so finally the project setup has to
integrate all the required disciplines as depicted below:
material science
thermodynamics
MCE-machine
market analysis
The interdisciplinarity of “MagKal”
was covered by the setup of the
project team. For the material aspects
and the engineering part the IFW was in charge.
The Technical University Dresden contributed to
the thermal issues. Finally an expert from the
electrical eng.
mechanical eng.
industries, called the innovation mentor, joined
the project team for guiding the activities in terms
of their relevance to the market.
The major key issues in the project are as follows:
쐍 Finding and characterizing of alternative MCE-materials to Gd
쐍 Identifying sufficient transfer fluid and optimization of heat transfer process
쐍 Building of the demonstrator
During the project term quite a number of actions were taken to meet the milestones
above. Some highlights are arranged exemplary below:
Funded by the Federal Ministry of Education and Research the „MagKal“-project was
evaluated among 137 others and was identified as a good-practice-example. The entire
project setup as well as the activities of the innovation mentor were regarded to be well
determined on applying the MCE technology in niches like e.g. electro mobility.
Compared to compressor refrigeration the MCE technology captivates with simple
reversibility of the thermal cycle and the total absence of fluids which may harm the
atmosphere. Nevertheless a real breakthrough in terms of replacing conventional compressor technologies in the mass market still needs appreciable efforts. The major key
issue to be solved is still the development of sufficient MCE materials, a field on which
future research activities should be focused.
(iv) Magnetic shape-memory alloys:
transformation mechanisms and finite size effects
In order to understand the transformation behavior of magnetic shape memory alloys
we localized the sources of acoustic emission during a martensitic transformation in
collaboration with the University of Barcelona and Academy of Science in Prague [8].
Acoustic avalanches are a general feature of solids under stress, e.g., evoked by external compression or arising from internal processes like martensitic phase transformations. From integral measurements, it is usually concluded that nucleation, phase
boundary pinning, or interface incompatibilities during this first-order phase transition
all may generate acoustic emission. We studied local sources of acoustic emission to
enlight the microscopic mechanisms. From two-dimensional spatially resolved acoustic
emission measurement and simultaneous optical observation of the surface, we identified microstructural events at the phase boundary that lead to acoustic emission. A
resolution in the 100-μm range was reached for the location of acoustic emission
sources on a coarse-grained Ni-Mn-Ga polycrystal. Both, the acoustic activity and the
size distribution of the microstructural transformation events, exhibit power-law
behavior. The origin of the acoustic emission are elastically incompatible areas, such
as differently oriented martensitic plates that meet each other, lamellae growing up to
grain boundaries, and grain boundaries in proximity to transforming grains. Using this
result, we proposed a model to explain the decrease of the critical exponent under a
mechanical stress or magnetic field.
To probe finite size effects in ferromagnetic shape memory nanoactuators, together with
the KIT double-beam structures with minimum dimensions down to 100 nm were designed, fabricated, and characterized in-situ in a scanning electron microscope with
respect to their coupled thermo-elastic and electro-thermal properties [9]. Electrical
resistance and mechanical beam bending tests demonstrate a reversible thermal shape
memory effect down to 100 nm. The comparison of surface and twin boundary energies
allow to explain why free-standing nanoactuators behave differently compared to
constrained geometries like films and nanocrystalline shape memory alloys.
(v) Interfaces in Nd-Fe-B magnets at the atomic scale
The crystal structure and chemical composition of interfaces in Nd-Fe-B magnets has
been studied at unprecedented spatial resolution using a combination of aberrationcorrected scanning transmission electron microscopy (STEM) and electron energy loss
spectroscopy (EELS). These techniques allowed variations in the concentrations of
minor alloying elements near the surfaces of the Nd 2(Fe,Co)14 B grains to be detected
on the atomic scale [10]. Figure 4 shows EELS elemental profiles overlaid on the
Fig. 4: The local distribution of elements at a
phase boundary in a Nd-Fe-B magnet shown at
the sub-nm scale by elemental profiles overlaid
on the corresponding image.
corresponding high angle annular dark field (HAADF) image. The image shows a grain
of Nd2(Fe,Co)14 B on the left and the interface to an intergranular phase on the right. The
last vertical line of bright points from the left is the terminating plane of atoms of the
Nd2(Fe,Co)14 B grain. Enrichment of Co in the outermost unit cell of the Nd2(Fe,Co)14 B
and interfacial segregation of Cu were observed (Fig. 4). Co is known to have a detrimental effect on the coercivity of the material but such local concentrations have not
been previously observed. Molecular dynamics simulations of grains with and without
Co enrichment at the surface showed that the magnetoelastic anisotropy was reduced
in the Co enriched region. This is also likely to have a detrimental influence on coercivity. The results contribute to the fundamental understanding of coercivity in Nd-Fe-B
magnets and may be used to guide experiments in enhancing coercivity in future
materials.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
F. Steckel et al., Phys. Rev. B 90, 134411 (2014)
A. Bauer et al., Phys. Rev. B 90, 064414 (2014)
S. Kauffmann-Weiss et al., APL Materials 2 (2014) 046107
L. Reichel et al., J. Appl. Phys. (2014) accepted
L. Reichel et al., J. Appl. Phys. 116 (2014) 213901
M. Krautz et al., Scripta Materialia 95 (2015) 50
B. Pulko et al., J. Magn. Magn. Mat. 375 (2014) 65
R. Niemann et al., Phys. Rev. B. 89 (2014) 214118
M. Kohl et al., Appl. Phys. Lett. 104 (2014) 043111
T. G. Woodcock et al., Acta Mater. 77 (2014) 111
Cooperation: 1 TU München, 2MLZ Garching, 3 Inst. Physics Prague, 4 Ruhr-University
Bochum, 5Helmholtz-Zentrum Dresden-Rossendorf, 6Demokritos National Center
of Scientific Research Athens, 7Uppsala University, 8 TU Darmstadt, 9University of
Ljubljana, 10Parker Hannifin Manufacturing Srl, 11Universitat de Barcelona,
12
Karlsruhe Institute of Technology, 13SuperSTEM, 14 University of Exeter,
15
Toyota Motor Corporation, 16 TU Dresden, Audi AG, TU Eindhoven, Polish Academy
of Sciences, Universität Kaiserslautern, Universität zu Köln, MPI CPFS, Dresden,
Ohio State University
Funding: Audi AG, DFG
Research Topic 1.4
Engineering magnetic microtextures
People: M. M. Abd-Elmeguid8, A. Barla7, A. N. Bogdanov, S. Chadov 6, M. Deutsch4, C. Felser 6 ,P. Fischer 2,
C. Hengst, J. Körner, K. Koepernik, F. Kronast1, E. Lopatina, D. Makarov, O. Meshcheriakova6, I. Mirebeau4,
Th. Mühl, A. K. Nayak 6, V. Neu, C. F. Reiche, U. K. Rößler, Z. Sasvari 3, R. Schäfer, M. Schmidt6, I. Soldatov,
R. Streubel, K. Tschulik, M. Uhlemann, S. Vock, H. Wilhelm5, M. Wolf, U. Wolff
Responsible Directors: B. Büchner, O. G. Schmidt, L. Schultz, J. van den Brink
Summary: The unique properties of non-trivial topological states, e.g. magnetic
skyrmions [1] may path the way towards novel spintronic devices [2]. However, these
spin textures have only been observed in special classes of materials possessing noncentrosymmetric crystal structure [1, 3-6] and at low temperatures, which limits their
application potential. Within research topic 1.4 we focus on realizing novel and configurable inhomogeneous magnetization states such as skyrmions and chiral domain
walls at room temperature and on their thorough static and dynamic study. Effort is
dedicated to the search of appropriate magnetic phases by first-principle calculations,
to the preparation of coupled multilayer systems with chiral magnetization states and
their investigation by magnetic x-ray and Kerr microscopy, and to the further development of optical and scanning probe microscopy techniques for an improved characterization of magnetic microtextures on variable length and time scales. The following examples summarize the progress in the theoretical description of chiral helimagnets,
in the realization of chiral magnetization states imprinted into Co/Pt/Py multilayers
and in new developments in magnetic force microscopy (MFM), namely depth resolved
quantitative MFM and a new sensing concept based on coupled oscillators .
Search for skyrmionic states and phases in chiral helimagnets
Search for skyrmionic states and phases in chiral helimagnets remains a challenge, owing to the specific requirements on symmetry and secondary magnetic properties like
magnetic anisotropies and magneto-elastic couplings. With a combination of theoretical and computational approaches we predict these properties in magnetic materials to
guide and support this search. In cooperation with external experimental groups we
have performed studies on the transition metal germanides FeGe and MnGe with
B20-structure, which are the archetypical chiral cubic helimagnets. In both materials,
the application of high pressure allows to reach unconventional magnetic states near the
collapse of magnetic order, while evidence for skyrmionic states exists for both compounds also at ambient pressure. A combination of neutron scattering experiments, magnetic measurements, and ab initio calculations uncovered an evidence for a spin-state
transition in MnGe from a high-spin to a low-spin transition under hydrostatic pressure
[7], an effect that has been predicted by us earlier. In future, it remains to be seen
whether the helimagnetism of MnGe with an uncommonly short and temperaturevariable period at ambient pressure can be explained by the proximity of the magnetic
system to this spin-state transition. In the classical chiral helimagnet FeGe, a Mössbauer
experiment under pressure shows the existence of an inhomogeneous chiral magnetic
precursor state [8]. In this quasi-static state reached without proper phase transition
from the paramagnetic side, the longitudinal magnitude of the spin-density is inhomogeneous and quasi-static on the time-scale of the Mössbauer experiment. The experiment provides important evidence for the unconventional type of magnetic ordering
transition via intermediate mesophases in chiral helimagnets. The interpretation of
the experimental results required a detailed calculation for the evolution under pressure
of the hyperfine parameters in FeGe by density-functional theory calculations using the
in-house FPLO-code.
We have started a cooperation with groups at the Max Planck Institute, CPFS Dresden to
analyse tetragonal Heusler-type compounds of type Mn2YZ. In these systems, ferrimagnetic or canted spin-structures with large non-collinear order and co-existence of
ferromagnetic and antiferromagnetic order-parameters in bicritical phase-diagrams
are combined with the existence of inhomogeneous Dzyaloshinskii-Moriya-couplings.
These complex and versatile systems promise novel types of skyrmionic states [8]. In
particular, the specific low symmetry of these compounds should allow to realize the
field-induced hexagonal skyrmion lattices that should be named Bogdanov-Hubertphase following the first prediction of this condensed skyrmion phase in the ground-state
of phase-diagram of chiral helimagnets in absence of competing conical helix-phases.
Magnetic chiral spin textures via imprinting
We offer an alternate route to design synthetic magnetic heterostructures that resemble swirls, vortices or skyrmions with distinct topological charge densities at room
temperature. By vertically stacking two magnetic nanopatterns with in- and out-of-plane
magnetization and tailoring the interlayer exchange coupling, non-collinear spin
textures with tunable topological charge can be imprinted (Fig. 1a).
The concept is demonstrated on nanostructures consisting of soft-magnetic 40 nm
thick Permalloy (Py, Ni80Fe 20) and 5 nm thick Co/Pd multilayers. First, we conduct
systematic micromagnetic simulations of the magnetic spin texture in a disk-like
heterostructure with a diameter of 400 nm where the interlayer exchange coupling
strength between Py and Co/Pd sub-systems is varied from 0.1 to 2 mJ/m2. In strongly
coupled heterostructure, the magnetic state of the Co/Pd is determined by the spin
configuration in the Py disk resulting in the in-plane circulation of the magnetization
thus resembling magnetic vortex state (Figs. 1b,c). At an intermediate coupling strength,
remanent donut states with a central vortex within the Co/Pd layers occur. Driving full
or minor hysteresis loops allows to stabilize topologically distinct donut states with topological charges of about 1 and 0. The resulting magnetic configuration of the donut state,
achieved at remanence after saturating the sample, is similar to those found in a disk with
Dzyaloshinskii-Moriya interaction [10] hence suggesting that skyrmion-like structures
can be experimentally realized in exchange coupled heterostructures. Owing to the
larger switching field of the vortex core compared to the surrounding Co/Pd spins, the
reversible switching between these states can be achieved. In this way, the topological
charge can be switched in a digital manner at room temperature and at zero field
Fig. 1: a) Conceptual figure: Vertically stacking the out-of-plane magnetized and magnetic
vortex state allows to imprint the non-collinear spin textures into the originally out-of-plane
magnetized film. (b) Ensemble of remanent states obtained by micromagnetic simulations of
nanopatterned disks. (c) Experimental proof via MXTM of imprinting magnetic vortices into
Co/Pd multilayers with originally out-of-plane anisotropy. (d) Simulations show that an intermediate interlayer coupling strength allows for switching the topological charge of donut states
at remanence and at room temperature by applying small magnetic fields. (e) Line profile of
the out-of-plane magnetization component for donut state I and II and magnetic spiral.
(Fig.1d). As our concept does not rely on vortex polarity switching in contrast to [11],
much lower static magnetic fields are needed to manipulate the topological state of the
material.
We have experimentally studied the magnetization reversal process and magnetic domain
patterns in nanostructured [Co/Pd]/Pd/Py stacks sputter deposited onto assemblies of
non-magnetic silica spheres with a diameter of 500 nm. The Pd spacer thickness is
varied from 1 to 30 nm. Evidence for the stabilization of non-collinear spin textures in
the Co/Pd layers is provided by direct imaging of the magnetization patterns utilizing
X-ray magnetic circular dichroism (XMCD) with high resolution magnetic soft X-ray
transmission microcopy (MTXM) and X-ray photoemission electron microscopy (XPEEM).
For a 1 nm spacer thickness a vortex structure is observed (Fig. 1c), in agreement with
theoretical predictions. At 3 nm spacer thickness, an out-of-plane magnetization
component appears in the Co/Pd sub-system. However, the circulation of the in-plane
magnetization component still remains. For this sample, we clearly identify formation
of different donut states as well as multi-domain states (Fig. 1e). The experimentally
resolvable in-plane XMCD contrast in Co/Pd stack vanishes for the sample with 5 nm
spacer thickness. The core of the imprinted vortex in the Co/Pd multilayer is enlarged
(60-110 nm) with respect to the Py vortex core due to the additional intrinsic out-ofplane anisotropy of Co/Pd.
Fig. 2: Calculated MFM signal (top right) in comparison with experimental MFM signal
(bottom right) of a CoFe nanowire array. The effective surface charge model (top left) is
based on the visible magnetization orientation within each nanowire and the precise charge
profile derived from micromagnetic simulations (bottom left).
Magnetic vortex observation in FeCo nanowires by
quantitative magnetic force microscopy (qMFM)
An approach is presented that allows quantifying the three dimensional magnetization
pattern of a magnetic nanoobject from measured two dimensional magnetic force
microscopy (MFM) data. It is based on (i) a MFM deconvolution approach, which quantitatively characterizes the imaging properties of a MFM tip at a given height above the
sample surface (tip transfer function) [12, 13], (ii) on a micromagnetic calculation of
the total magnetic charges of the magnetic nanoobject and a projection of the lower lying charges onto the sample surface, (iii) a convolution of the such obtained effective
surface charges with the tip transfer function to obtain a theoretical MFM image, and (iv)
a comparison with the experimentally measured MFM signal.
By making use of the depth sensitivity of MFM and by applying a quantitative contrast
analysis, we are able to reconstruct the inhomogeneous magnetization state at the end
of individual cylindrical Fe 52 Co48 nanowires arranged in a triangular array. Figure 2 shows
an experimental top-surface MFM image of a CoFe nanowire array in its demagnetized
state with arbitrary magnetization state (either up or down) along the length of each
nanowire, visible from the dark or bright contrast. A surface charge model is convolved
with the tip transfer function (TTF) of the previously characterized MFM tip, resulting in
a theoretical MFM pattern. Assuming a homogeneously magnetized nanowire with
appropriate saturation polarization overestimates the measured signal by a factor of 2
(not shown here). Including the magnetization vortex at the very end of the nanowires
as derived from micromagnetic calculations not only leads to a very good qualitative
but also to a perfect quantitative agreement. This is the first experimental proof of the
vortex state at the end of an embedded magnetic nanowire [14].
Fig. 3: Sketch of a coupled mechanical oscillator, consisting of a micron-sized oscillator (1)
and a nanowire oscillator (2), with interaction to be measured.
Nanomagnetic probes and magnetometers based on coupled oscillators
We developed a concept of coupled mechanical oscillators consisting of a nanowire oscillator (2) attached to a micron-sized oscillator (1) with tuned eigenfrequencies of the
individual oscillators (Fig. 3). Applied to cantilever magnetometry and magnetic force
microscopy, such coupled systems constitute very sensitive probes. This concept has been
confirmed by simulations (Fig. 3) and first experiments.
[1]
[2]
[3]
[4]
[5]
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[7]
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F. Jonietz et al., Science 330 (2010) 1648
S. Heinze et al., Nat. Phys. 7 (2011) 713
N. Kanazawa et al., Phys. Rev. Lett. 106 (2011) 156603
M. Deutsch et al., Phys. Rev. B 89 (2014) 180407(R)
A. Barla et al., Phys. Rev. Lett. 114 (2015) 016803
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Funding: DFG, ERC
Cooperation: 1BESSY II, Germany; 2 Lawrence Berkeley National Laboratory, USA;
TU Dresden, Germany; 4CEA Saclay, Laboratoire Leon Brillouin, France; 5Diamond
Light Source, UK; 6Max Planck Institute, CPFS Dresden, Germany; 7University Cologne,
Germany; 8ALBA Synchrotrone, Barcelona, Spain
3
Research Topic 1.5
Topological states of matter
Authors: S. Kourtis, T. Neupert 1, C. Chamon2, C. Mudry 3, M. Daghofer
People involved: B. Dassonneville, J. Dufouleur, V. Fomin, H. Funke, R. Giraud, S. Hampel, V. Kataev,
F. Kirtschig, K. Koepernik, A. Lau, P. Leksin, S. Li, L. Ma, U. Nitzsche, C. Nowka, C. Ortix, S. Pandey,
G. Prando, M. Richter, L. Veyrat, T. Weißbach, K. Wruck, Y. Yin, S. Zimmermann, J. Zocher
Responsible Directors: B. Büchner, O. G. Schmidt, J. van den Brink
Strong correlations in Chern bands
The recently discovered prospect of realizing fractional quantum-Hall (FQH) states with
the inclusion of short-range interactions in lattice models has garnered considerable
interest. Apart from a paradigmatic extension of the FQH effect to lattices, these states,
called fractional Chern insulators (FCI), arise without an externally applied magnetic
field. Hence, they are an important conceptual step towards potential technological
applications.
There are already several proposals for the realization of FCI states, some of which involve optical lattices, while others are based on known material structures, such as
strained or irradiated graphene, oxide heterostructures, or layered multi-orbital systems
proposed by our group [1, 2]. The latter category is particularly promising, since the
energy scales at which the desired physics emerges is of the order of room temperature.
Since their inception, FCI states have been studied with various numerical and analytical methods. Of particular interest are works that emphasize the differences between
FCI states and traditional FQH physics. The most obvious difference is that Chern bands,
unlike Landau levels, have a non-vanishing dispersion. In an earlier work, we have
proven by example that this dispersion may actually favor FCI states [2]. Unlike FQH
systems, FCI models can be naturally extended to include both spin species, and it has
been shown that the resulting time reversal-symmetric models can be hosts of fractional topological insulators. Since the Chern number of a band can, in contrast to a
Landau level, take values larger than one, FCI states can occur in partially filled bands
with higher Chern numbers. Finally, topologically ordered states that go markedly
beyond the Landau-level picture, in which the topological character is combined with
Landau-type order, have been found by two of us recently [3].
Fig. 1: Phase diagrams of (a) the triangular
and (b) the checkerboard lattice models on
a 48-site cluster at ν = 1/3, V1 = ∞ in the
plane spanned by the chemical potential
μ s and the third nearest-neighbor hopping
t 3.The color coding is the lowest value of the
gap between FCI ground states and excited
states upon flux insertion. The dashed white
line in (b) denotes the phase boundary for
the non-interacting model.
If one wishes to search for FCI states in the laboratory, understanding of how these states
can arise in realistic multiband systems is crucial. In Ref. [4], we pose two fundamental
questions for the realization of FCI states, namely (i) whether the mixing of bands by
interactions leaves space for FCI states to arise, and (ii) whether FCI states can be found
far beyond the energy scale of the band gap. To this end, we have studied two prototypical two-sublattice FCI models using exact diagonalization, taking both Chern bands
into account [4]. We show that FCI states survive band mixing caused by arbitrarily large
interactions. To demonstrate this, we introduce the extreme limit of nearest-neighbor
interaction going to infinity. In this regime, particles dressed by the interaction form
extended objects, which can be interpreted as non-interacting hardcore particles
occupying more than one lattice sites. We find that strong interactions of magnitude far
larger than the band gap may actually favor FCI states, regardless of whether the bands
are mixed, see Fig. 1.
Within the FCI regime (the colored part of the phase diagrams in Fig. 1), the ground-state
eigenvalues exhibit the empirical characteristic features of FCI states: 3-fold degeneracy and spectral flow. In order to establish beyond doubt that the phase is indeed an
FCI, we calculate the Hall conductivity in this regime and find it to be very precisely
quantized to the value -1/3 [4].
In [3], we go beyond the limit of „weak“ interactions, into a regime where different Chern
bands mix. We find states that show the features of both a CDW and of an FCI and, thus,
arrive at an exotic state of matter that is characterized by both Landau-type and
topological order and is understood in terms of both band topology and lattice geometry. This novel class of states can be intuitively understood as comprising of particles
that play two roles simultaneously. Most of them form the CDW occupying 1/3 of the triangular lattice sites, see Fig. 2(b). Additional particles can then move on the remaining
sites, up to a total density of n = 2/3 (two fermions per three lattice sites). One can view
the remaining sites as an effective honeycomb-lattice model, which has here a 4-site unit
cell, see Fig. 2 (b), and is described by topologically nontrivial hoppings.
Fig. 2: Charge density wave (CDW) and fractional Chern insulator (FCI) on the triangular
lattice at a density n = 1/3. (a) Phase diagram of the model used in Ref. [3] for a 3 x 3 unit-cell
(6 x 3 lattice-site) system with 6 fermions and only nearest-neighbor repulsions V1.
(b) The 4 x 4 - 1 = 15 unit-cell (30 lattice-site) cluster used in Ref. [3]: the unit cell (black/red
circles), the charge-order pattern (filled circles) arising in the CDW and the hoppings. Solid,
dashed and arrowed black lines represent complex hoppings t with phases of 0, π and ± π/2,
respectively. Grey lines denote hoppings deactivated by the CDW. Third nearest-neighbor
hoppings t’ are not shown.
The eigenvalue spectra of our interacting spinless-fermion model on the triangular
lattice at filling fractions ν = 12/15 and 13/15 hint at ground states that are neither FCI
nor CDW, but have features of both. The Landau order, commensurate charge modulation
in the ground states, reveals itself in the interaction strength-dependent peaks in the
static charge-structure factor. The topological order is established via the Hall conductivity, which is precisely quantized, but with a value σH ≠ ν. Instead, we find a quantization consistent with viewing the ground states as composites of a CDW state and a FCI
state formed by additional particles in the part of the lattice that remains unoccupied
by the CDW [3].
[1]
[2]
[3]
[4]
J.W.F. Venderbos et al., Phys. Rev. Lett. 108 (2012) 126405.
S. Kourtis et al., Phys. Rev. B 86 (2012) 235118.
S. Kourtis and M. Daghofer, Phys. Rev. Lett. 113 (2014) 216404.
S. Kourtis et al., Phys. Rev. Lett. 112 (2014) 126806.
Collaborations: 1Princeton University, Princeton, New Jersey 08544, USA;
2
Boston University, Boston, Massachusetts 02215, USA;
3
Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
Funding: DFG
Research Area 2 FUNCTION THROUGH SIZE 31
Research Topic 2.1
Non-equilibrium phases and materials
Authors: S. Pauly, J. Freudenberger, S. Scudino, U. Rößler
People involved: H. Attar, M. Calin, B. Escher, P. Gargarella, T. Gemming, I. Kaban, A. Kauffmann, M. Samadi Khoshkhoo,
K. Kosiba, U. Kühn, P. Ma, K. G. Prashanth, P. Ramasamy, H. Shakur Shahabi, M. Stoica, H. Turnow, Z. Wang, H. Wendrock
Responsible Directors: J. Eckert, L. Schultz, J. van den Brink
Summary: The most prominent characteristic of non-equilibrium materials is the
energetically unfavourable state they have adopted during their synthesis. The entire
microstructure or parts of these materials are in structural, compositional or morphological metastability, which defines their unusual and interesting mechanical, chemical and physical properties [1]. Some of the eldest and probably best-known examples
comprise silicate glasses or martensite formation in steels.
A wide variety of other, novel non-equilibrium materials are the objects of the research
conducted in research area 2.1. The present report shall give a glimpse of the diversity of materials and methods used to obtain and to characterise them. Therefore, as a
cross section, this treatise covers bulk metallic glasses (BMGs), BMG matrix composites, cryomilled, nanostructured Cu as well as heavily deformed metals and alloys.
Strain determination in a metallic glass by X-rays
Fig. 1: Schematic setup of the diffraction experiment
at the ESRF. The beam is parallel to the imprinted
grooves at the sample surface. For each point
indicated a 2D-diffraction pattern was recorded and
then integrated. The shift in the peak positions
reflects the local strains in the glass.
Understanding the deformation mechanisms in metallic glasses is a very challenging
task. The structural entities, which govern deformation in metallic glasses (shear
transformation zones, STZs), are of very small size and cannot be unveiled directly
[2,3]. However, diffraction using high-energy X-rays is capable of revealing details of the
structure, which allow the determination of the local strain state in the glass [4,5]. That
way, the occurrence of shear bands, which result from the coalescence of STZs, can be
better understood and their formation can be correlated with the local strains–or the
structure.
Here, the surface of a Zr 52.5Ti5Cu18Ni14.5 Al 10 bulk metallic glass was structured by imprinting a line pattern with a steel mould at room temperature [6]. This forces the glass to
deform plastically and leaves periodic grooves at the surface (Fig. 1). The sample was
then scanned with a high-energy X-ray beam (Fig. 1) and the local strains were calculated from the shift of the first diffraction maximum [4,7].
32 Research Area 2 FUNCTION THROUGH SIZE
Fig. 2: Components of the strain tensors of the
imprinted glass.
(a) εxx (tangential): parallel to the imprinted surface.
(b) εyy (axial): normal to the imprinted surface and
(c) εxy : in-plane shear. Oscillations between compressive and tensile strains can be revealed and especially
the in-plane shear is rather pronounced.
The three components of the strain tensor (εxx , εy y , εxy) were determined for each
point to create spatially resolved strain maps. Figures 2(a) - 2(c) show the strain components, which are negative for compressive and positive for tensile strains. Characteristic patterns of alternating tensile and compressive strains are obtained. Especially the
in-plane strains (εxy) are rather pronounced. A comparison between the medium-range
order (MRO, first diffraction maximum) and the short-range order (SRO, higher order
maxima) suggests a significant structural anisotropy. The shear strains in Fig. 2 are
much larger than the elastic shear components obtained from X-ray experiments during
uniaxial loading, which are close to zero [4,8]. The shear band pattern after deformation of the imprinted BMGs clearly proves that the generation of shear bands is governed
and affected by these residual strains.
Steel spring-metallic glass composite
Monolithic bulk metallic glasses tend to fail in a brittle fashion [9]. The reason for this
is the formation of shear bands already mentioned above. Once they form, the glass
becomes softer and the shear bands preferentially transform into cracks [2,9]. One way
to overcome this limited damage tolerance is to incorporate a second, crystalline phase
[10,11]. The crystalline phase interacts with the formation of these shear bands and
aggravates their propagation and thus retards fracture [10].
A special case of such a composite is shown in Fig. 3: a steel spring of a ball pen was
infiltrated by a glass-forming Zr52.5Ti5Cu18 Ni14.5 Al 10 melt (inset in Fig. 3) [12]. The longitudinal cut of this sample shows the glassy matrix and the relatively darker steel spring
(Fig. 3). Even though the wetting of the spring is not always sufficient (voids in Fig. 3)
the plasticity can be significantly enhanced as the compression tests prove (Fig. 4 (a)).
The strength of the composite is somewhat lower but this sacrifice is counterbalanced
by a substantial increase in the plastic deformability. Moreover, the dynamics of the shear
banding process are altered due to the presence of the steel spring. Relatively large stress
drops followed by elastic loading are observed in the case of the as-cast metallic glass
(Fig. 4 (b)). In contrast, much more serrations appear in the spring-glass composite and
the energy release for each serration is also much smaller.
Fig. 3: Micrograph (scanning electron microscope)
of longitudinal cut through the spring-glass composite. The dark circles represent the spring and
the inset illustrates how the spring was infiltrated.
Fig. 4: (a) Stress-strain curves of the composite in
compression. The composite has a much larger plastic
deformability and also the dynamics of the shear
banding process changes. (b) for the as-cast material
less serration events occur and the elastic energy
density of each event is larger than in the case of
the composite (c).
Nanostructured Cu through cryomilling
The metallic glasses mentioned above were all obtained via quenching of a melt. Another route to obtain glasses for instance is ball milling [1]. Depending on the powder
composition and the milling parameters not only metallic glasses can be synthesised but
also nanocrystalline metallic materials [13]. In this context, it is crucial to understand
the mechanisms as of how the nano-scale microstructure evolves. This can be done by
detailed X-ray diffraction line analysis coupled with high-resolution transmission
electron microscopy (TEM) [14].
The grain size for cryomilled Cu obtained by TEM ranges between 10 and 200 nm
(Fig. 5(a)). This is different compared to the size distribution obtained by XRD because
for deformed Cu XRD provides the size distribution of dislocation cells, while TEM gives
the grain size distribution. There is no sign of discontinuous dynamic recrystallisation
(DDRX). Microstructural refinement occurs via dislocation activity including dislocation
generation and accumulation, annihilation and recombination of dislocations to form
dislocation cells, and gradual conversion of the dislocation cells to individual grains.
Cu-Zn15, however, has a reduced stacking fault energy and contains very small
grains with size in the range of 5 -10 nm within a heavily strained matrix made of
larger grains (50 - 150 nm) (Fig. 5(b)). These grains are due to the occurrence of DDRX.
Dynamic recover y is inhibited and dislocation density reaches a critical value at which
dynamic recrystallisation may initiate. Both structural decomposition and dynamic
recrystallisation are responsible for nanostructure formation during cryomilling of
Cu-Zn alloys.
Phase transformation kinetics
Fig. 5: Frequency of grain sizes in cryomilled
(a) Cu and (b) Cu-Zn15. The histogram represents
the grain sizes obtained by high-resolution TEM and
the curve is obtained from X-ray diffraction line profile analysis. Due to the lower stacking fault energy,
discontinuous dynamic recrystallization only occurs
in the Cu-Zn15 alloy.
The formation of phases from non-equilibrium conditions as e.g. heavily deformed
metallic materials and composites is a measure of the phase stability of the non-equilibrium state in terms of the variables of state and time. At the same time the irreversible
transformation from one state to another is comprised by a change of the microstructure. Hence, it is of great importance to detect and understand microstructural changes
as well as to link them to the underlying mechanisms. Such transformations can readily be detected by in-situ R(T) measurements, as e.g. the formation of intermetallic
phases such as TiAl from pure elements of recrystallisation processes as described below. As mentioned before, the microstructure of single-phase copper alloys can be altered
by cold deformation. Depending on the processing parameters like temperature or the
stacking fault energy, the dominant deformation mechanism is different and the refinement of the microstructure bears other rates with respect to the deformation strain. The
formation of deformation twins is activated at low homologous temperature or at low
Fig. 6: Microstructure of Cu, CuAl1 and CuAl3 after deformation at cryogenic conditions and
the derivative of the resistivity with respect to the temperature.
stacking fault energy leading to smaller grain sizes achieved at a certain deformation
strain. Figure 6 shows the microstructures of Cu-Al alloys after deformation at cryogenic
conditions and the results of in-situ resistivity measurements. The resistivity changes
associated with microstructural changes during recovery and recrystallisation during
heating are highlighted by the derivative of the resistivity with respect to the temperature. Deviations of dρ/dT from this ρ 0 α value indicate changes of the densities of
defects acting as scattering centres for electrons.
Lowering the temperature during deformation causes a significant reduction of the
characteristic temperature when compared to the deformation at room temperature.
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R.W. Cahn, A.L. Greer, in: R.W. Cahn, P. Haasen (Eds.),
Physical Metallurgy, Elsevier, Amsterdam, 1996, pp. 1724 - 1830.
C.A. Schuh et al., Acta Mater. 55 (2007) 4067.
M.W. Chen, Annu. Rev. Mater. Res. 38 (2008) 445.
H.F. Poulsen et al., Nature Mater. 4 (2005) 33.
M. Stoica et al., J. Appl. Phys. 104 (2008) 013522.
S. Scudino et al., Scripta Mater. 65 (2011) 815.
T.C. Hufnagel et al., Phys. Rev. B 73 (2006) 064204.
J. Das et al., Rev. B 76 (2007) 092203.
H.S. Chen, Rep. Progr. Physics 43 (1980) 353.
J. Eckert et al., 22 (2007) 285.
C.C. Hays et al., Phys. Rev. Lett. 84 (2000) 2901.
H. Shakur Shahabi et al., Mater. Design 59 (2014) 241.
C. Suryanarayana, Progr. Mater. Sci. 46 (2001) 1.
M. Samadi Khoshkhoo et al., Mater. Lett. 108 (2014) 343.
Funding: DFG, US NSF, EU (BioTiNet-ITN), EU (VitriMetTech-ITN), ECEMP, Natural
Science Foundation of China Foundation, Australian Research Council’s Projects
funding scheme, Alexander von Humboldt Foundation (AvH), Pakistan Institute for
Engineering and Applied Sciences (PIEAS), European Synchrotron Radiation Facility
(ESRF), Deutscher Akademischer Austauschdienst (DAAD), China Scholarship Council,
Ministry of Knowledge Economy, Republic of Korea
Cooperation: University of Vienna, Austria; University of São Carlos, Brazil;
University of Cambridge, United Kingdom; University of Turino, Italy; Harbin Institute
of Technology, People’s Republic of China; Edith Cowan University, Perth, Australia;
Indian Institute of Technology (BHU), Varanasi, India; Yonsei University, Seoul,
Korea; Tohoku University, Sendai, Japan
Research topic 2.2
Intelligent hybrid structures
People: D. Ehinger, B. Escher, J. Freudenberger, D. Geißler, T. Gustmann, J. K. Hufenbach, H. Y. Jung,
K. Kosiba, U. Kühn, S. Pauly, P. Ramasamy, B. Sarac, D. Sopu, A. Strehle, M. Stoica, H. Y. Jung
Responsible Directors: J. Eckert, L. Schultz
Summary: The key concept of this research topic is to define new routes for creation of
tailored metallic materials based on scale-bridging intelligent hybrid structures
enabling property as well as function optimization. The novelty - as compared to
conventional ideas - is that they apply to monolithic amorphous or bulk (nano-)microcrystalline materials. The basis is founded on innovative strategies for the design,
synthesis and characterization of intrinsic length-scale modulation and phase transformation under highly non-equilibrium conditions. This includes the incorporation of
dispersed phases which are close to or beyond their thermodynamic and mechanical
stability limit, thus forming hierarchically structured and ductile/tough hybrid alloys.
Alternatively, the material itself is designed in a manner such that it is at the verge of
its thermodynamic/mechanical stability.
Deformable soft-magnetic bulk metallic glasses (BMGs)
Ferromagnetic Fe- and (Fe,Co)-based amorphous alloys are regarded as attractive industrial alloys due to relative low price and simple routes for fabrication. Within several new
BMGs developed in the last decade, the [(Fe 0.5Co0.5)0.75 Si 0.05 B0.20 ] 96 Nb4 glassy alloy
plays an important role because it combines a high glass-forming ability (GFA) with good
soft-magnetic properties and very high compressive strength. However, a major drawback of almost all Fe- and (Fe,Co)-based BMGs, which hinders their application, is the
absence of sufficient plastic deformation. Generally, the routes used to enhance the
deformability of glassy alloys point towards creation of a composite structure or designed heterogeneities, for example, through mechanical pre-loading or severe plastic
deformation. These methods must be applied eventually with caution to Fe- and (Fe,Co)based alloys, because the soft magnetic properties can deteriorate in the presence of
non-magnetic crystalline phase(s) or due to the stress induced by mechanical treatment.
A solution for magnetic BMGs can be fine-tuning the composition by adding element(s)
with large Poisson ratio such as, for example, Ni or minor additions of Cu. By adding
0.5 at.% Cu to the aforementioned composition we created - for the first time - a
FINEMET ®-type BMG with enhanced deformability [1]. Monolithic samples with 1 mm
Fig. 1: Time-resolved X-ray diffraction in
transmission configuration measured for
{[(Fe 0.5Co 0.5 )0.75 Si 0.05 B 0.20 ] 96 Nb4 } 99.5Cu 0.5 BMG.
The complete measurements is truncated here
between 794 K and 910 K, i.e. it starts in the supercooled liquid region of the initial fully amorphous
and homogeneous BMG sample and finishes within
the supercooled liquid region of the remaining
amorphous matrix.
diameter revealed a fracture strain of 3.80 % and a maximum stress of 4143 MPa upon
compression, together with a slight work hardening-like behavior. The soft magnetic
properties are preserved upon Cu-addition and the samples show a saturation magnetization of 1.1 T combined with less than 2 A/m coercivity. The Cu-added glasses show
a very good thermal stability but, in comparison with the base alloy, the entire crystallization behavior is drastically changed [2]. Upon heating, the new glassy samples
show two glass transition-like events, separated by an interval of more than 100 K, in
between which a BCC-(Fe,Co) solid solution is formed. This unique behavior was investigated by time-resolved X-ray diffraction in transmission configuration, using a highintensity high-energy monochromatic synchrotron beam at the ID11 beamline at ESRF
Grenoble, France. The patterns presented in Fig.1 start at 794 K, i.e. in the supercooled
liquid region of the initial fully amorphous and homogeneous BMG sample and finish
at 910 K, within the supercooled liquid region of the remaining amorphous matrix. The
crystalline peaks superimposed to the amorphous background are characteristic for a
BCC-(Fe,Co) solid solution. By appropriate control of the size and distribution of the
nanograins this behavior can be further exploited for enhancing the soft magnetic
properties as well as the plastic deformability even more.
BMG-Matrix Composites with crystalline TRIP/TWIP particle reinforcement
It has been shown that crystalline inclusions or precipitates can enhance tensile plasticity of the BMGs. One general approach is to arrest single localized shear bands and/or
to disperse the material reaction into multiple shear banding in order to retard failure.
With the background of Twinning Induced Plasticity (TWIP) and Transformation Induced
Plasticity (TRIP) [3-5] it is envisaged to create new BMG-Matrix Composites that have an
active component as second phase. This approach has already been proven to be successful by using the formation of B2 CuZr-type particles within an amorphous CuZr-based
matrix [6] that show work hardening and interact with shear bands by deformation twinning and martensitic phase transformation. We extended this approach by producing
BMG-Matrix Composites through Selective Laser Melting (SLM) [7]. Here, Fe-based
amorphous powders that have been successfully processed by SLM [7] into bulk amorphous samples were mixed with powders from Shape Memory Alloys (SMA) and coprocessed via SLM into BMG-Matrix Composites. Within the active temperature range
of the SMA, similar beneficial effects on the mechanical properties of the BMG matrix
are expected as stated above. First tests show that bulk structures can be additively
manufactured from mixtures of Fe 74 Mo4 P10 C7.5B2.5 Si2 (at.%) based amorphous powders
and Cu-11.8Al-3.2Ni-3.0Mn (wt.%) SMA powders by the SLM technique. Fig. 2 shows
hollow cylinders with 4 mm diameter and 8 mm height processed via SLM from a 9:1
Fig. 2: Hollow cylinders with 4 mm diameter and
8 mm height processed via SLM from a 9:1 mixture
of a Fe 74 Mo4 P10 C 7.5 B 2.5 Si 2 (at.%) gas atomized
amorphous powder and a Cu-11.8Al-3.2Ni-3.0Mn
(wt.%) SMA powder: (a) using the set of parameters
adapted to the SLM of the Fe-based powder as in [7],
(b) improved set of parameters adapted to the SLM
of the Cu-based SMA.
mixture of these FeMoPCBSi gas atomized amorphous and CuAlNiMn SMA powders
manufactured using (a) a SLM set of parameters adapted to the processing of Fe-based
powder [7] and (b) an improved set of parameters, adapted to the SLM of the Cu-based
SMA. The properties of these composites are currently investigated.
Development and study of Co-based metallic glasses and composites
Another subject of the INTELHYB research topic focuses on the development and study
of novel high-strength and soft-magnetic Co-based metallic glasses and composites.
Since direct casting of these materials into rods is very challenging and mostly unsuccessful, other techniques like melt-spinning and gas-atomization were applied as
the pre-processing steps. The investigated melt-spun Co66 Hf6.5B27.5, Co 56Fe 10Hf6.5B 27.5
and Co40 Fe 22 Hf6.5B31.5 (at.%) amorphous ribbons exhibit average thicknesses in the
range of 18 to 67 μm, and band widths between 1.5 and 4 mm depending on the chamber pressure, the wheel speed and the casting temperature. So far, the best surface quality and highest bend fracture angle (as a first indicator for ductility) was achieved for
Co 56Fe 10Hf6.5B 27.5 ribbons. Fig. 3(a) shows an as-spun 1.5 mm wide Co 56Fe 10Hf6.5B 27.5
ribbon which exhibited the best deformability. The ribbon is very uniform and ductile.
Yet, there are still demands for optimization with respect to the sample dimensions for
potential future applications.
Fig. 3: (a) As-spun 1.5 mm wide very uniform and
ductile Co 56 Fe10 Hf6.5 B 27.5 ribbon showing the best
deformability. (b) Snapshot of the atomization
process of the Co 40 Fe 22Ta 8 B 30 alloy. The central
stream of the molten alloy is further spread at the
intersection of the water jet (the laminar jet in the
picture coming out from the left nozzle) and the
symmetrical Ar gas jet (invisible here, coming out
from the right nozzle). The powder is collected in a
water-filled tank placed below the atomization point.
Co40Fe 22Ta8B30 and Fe-based reference materials were gas-atomized by ejecting the
molten metal via a dual in-house upgraded water/Ar jet system, and finally quenching
in water. The powders have a narrow particle size distribution between 100-150 μm for
a nozzle slit-size of 700 μm. Fig. 3(b) shows a snapshot of the atomization process of
the Co40 Fe 22Ta 8B30 alloy. One can observe the central stream of the molten alloy
which is further spread at the intersection of the water jet (the laminar jet in the picture
coming out from the left nozzle) and the Ar gas jet (invisible in the picture, coming out
from the right nozzle). The powder is collected in a water-filled tank placed below the
atomization point. According to DSC and XRD measurements, the spherical Co-based
particles are coated by an oxide layer. Therefore, additional manufacturing steps such
as ball milling and chemical treatment (e.g. etching) are necessary to confirm amorphization of the inner core material.
As a future prospect, melt-spinning will be applied to the new master alloy family,
(Co64.8B 28 Si 7.2) 96 Hf4 and (Co68.8 B 25.7Si 5.7)96 Hf4 , whose stoichiometry is attributed to
the cluster line approach for the ternary Co-B-Si system. In general, hafnium is used to
increase the glass-forming ability and bonding strength, however it has a high affinity
to residual oxygen in the environment, as already observed by first injection/suction
casting and gas atomization tests. Based on the principle from previous research works
[8-10], granules or flakes made of ball-milled amorphous ribbons and gas-atomized
amorphous powders can be used for different consolidation processes. Future activities
will consist of hot forming and selective laser melting of Co-based feedstock to investigate the mechanical and structural properties of bulk glassy samples and composites.
Molecular dynamics simulations of the deformation behavior
of metallic glass composites
Many literature results in the field of BMGs and their composites were obtained upon
“trial and error” methods. The INTELHYB research project aims to study in-depth the
theoretical aspects of the mechanical behavior with the help of mathematic models.
Therefore special efforts are focused towards theoretical design and optimization. By
computer simulations we provide detailed insights into the structure and properties of
metallic glasses and composites at the atomic level.
As discussed previously, in case of monolithic BMGs the plasticity is localized in a few
dominant shear bands, as displayed by the red colored spots (which indicate the stress
concentration) in Fig. 4(a). One of these shear bands can go critical resulting in brittle
failure of the material. In order to improve the mechanical properties of metallic
glasses a promising way is to form composites containing a secondary crystalline phase.
We simulated the deformation mechanism of a Cu 64 Zr36 metallic glass composite in form
of a laminate embedded between two B2 CuZr crystalline plates which may undergo
stress-induced martensitic transformation. Fig. 4(b) refers to this situation. Upon
tensile deformation, above a critical stress level, the crystalline plate undergoes a
martensitic transformation from B2 (blue atoms in the picture) to FCC phase (green atoms
in the picture). When the crystalline plate and the metallic glass are joined together
a new hybrid structure is formed, which shows a completely different mechanical
behavior (Fig. 4(c)). First, the plasticity in the glassy phase is no more localized in one
dominant shear band as in the case of bulk glass. Many shear bands form (red colored
spots) and they try to avoid those areas where the crystalline plates exhibit martensitic
transformation (here colored in grey). In other words, there it is a strong competition
between the glassy and crystalline phases to accommodate the elastic energy. Moreover,
it seems that the residual elastic energy is not large enough to induce a transformation
from the B2 to FCC phase as found for crystalline plates. Rather, the crystalline plates
transform from the B2 to the tetragonal phase (Fig. 4(c), marked with gray spots) and
this transformation follows the 45 degree shearing direction. All these preliminary
results provide clear evidence that the mechanical properties of composite materials can
be tuned by controlling the crystalline fraction, phase, orientation, size, geometry, etc.
Further studies will be conducted to provide a clear understanding of the deformation
behavior of hybrid materials and to improve the ductility of this class of materials.
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Funding: EU (ERC Advanced Grant)
Cooperation: Institute National Politechnique Grenoble (INPG), France; European
Synchrotron Radiation Facility (ESRF) Grenoble, France; Deutsches Elektronen-Synchrotron (DESY) Hamburg, Germany; Auerhammer Metallwerk GmbH, Aue, Germany;
Yonsei University, Seoul, Korea; Tohoku University, Sendai, Japan; University Vienna,
Vienna, Austria
BMG
Crystal
Composites
Fig. 4: Molecular dynamics simulations of
the deformation mechanism of a bulk
metallic glass (a), a B2 crystalline plate (b)
and a composite structure formed by joining
both of them (c). All samples are deformed
in tension with a strain rate of 4 x 10 7 s-1
at 50 K.
Research topic 2.3
Multifunctional inorganic nanomembranes
Authors: V. M. Fomin, D. Karnaushenko, G. Lin, V. Magdanz, D. Makarov, M. Melzer, S. Sanchez, R. Schäfer, R. Streubel
People involved: S. Pandey, C. Ortix, L. Ma, T. Gemming, G. Stoychev 1, L. Ionov 1, R. O. Rezaev 2,3, E. A. Levchenko2,
F. Kronast 4, P. Fischer 5, S.-K. Kim6, M. Kaltenbrunner 7
Responsible Directors: O. G. Schmidt, J. Eckert, L. Schultz, J. van den Brink
Summary: Inorganic nanomembranes are flexible and can be transferred to virtually
any substrate. This allows for transforming rigid electronic elements into their flexible counterparts with the goal to make consumer electronics thin, lightweight, and
compliant. We aim at (i) understanding the electronic, magnetic, and optical properties of thin films with tunable curvature and (ii) realizing electronics with multiple
diagnostic and communication capabilities at different length scales from large area
wearable electronics down to compact Lab-in-a-Tube devices.
Stimuli responsive microjets: Artficial micromotors offer great possibilities for research
spanning from fundamental mechanisms of motion [1-3] at the micro-and-nanoscale to
potential biomedical [4-7] and environmental applications [8-10]. In collaboration
with Ionov’s group from the Institute for Polymer research, IPF Dresden, a new kind of
flexible artificial micromotor was demonstrated (Fig. 1) [11]. In this case, thermoresponsive microjets are generated from two layers of polymers (polycaprolactone and
poly(N-isopropylacrylamide)) with a thin inner platinum layer which form a microtube
upon release from the substrate. These self-folding micromotors move autonomously
due to the catalysis of hydrogen peroxide on the platinum surface. The flexible microjets can reversibly fold and unfold by applying changes in temperature. This effect allows
the microjets to rapidly start and stop multiple times by controlling the folding of the
microjet. This new approach offers a convenient speed control mechanism during the
operation of catalytic micromotors and is especially interesting for studies on bubble
formation inside tubes.
Fig. 1: Flexible self-propelled microjets are formed by temperature-induced folding of
thin polymer films into microtubes that contain an inner platinum layer for catalytic bubble
propulsion in hydrogen peroxide. The polymer films are bilayers of an active and a passive
component, which cause the microjets to fold and unfold reversibly by applying slight temperature changes. The speed control by shaping the polymeric Pt films offers a unique approach
to operate this new kind of flexible bubble-propelled micromotors. The image is taken from
V. Magdanz et al., Angew. Chem. 126, 2711 (2014).
Vortex dynamics influenced by pinning centers and collective phenomena in superconductor microtubes: Dynamics of superconducting vortices in micro- and nanostructures are determined by a number of interplaying factors, including geometry, pinning
centers and collective phenomena. We have demonstrated that detection of curvature
effects on vortex dynamics [12] stays feasible in the presence of the pinning centers. The
impact of pinning centers on vortex dynamics on Nb superconductor open microtubes
[13] (Fig. 2a) has been analyzed. Certain regions on a tube have been revealed, where
the presence of pinning centers is especially significant for vortex dynamics (Fig. 2b).
The occurrence of bifurcation of the vortex trajectories is explained as a resulting effect
of three factors [14]: the nucleation rate, the Magnus force and the repulsion of vortices
from each other. Starting from a certain value of the magnetic field, which depends on
geometrical parameters of the tube, the potential energy is lowered by changing the
vortex configuration, namely, by splitting a dense row into two sparse rows (Fig. 2c). Our
results imply that superconductor open microtubes can be used as efficient vortex
transport elements for fluxon-based information technologies.
Fig. 2: (a) Schematic view of an open tube.
Electrodes are displayed by the heavy red lines.
B is the applied magnetic field. Distribution of the
squared modulus of the superconducting order
parameter |ψ| 2 at the magnetic flux (in units of
the magnetic flux quantum Φ0 ) Φ/Φ0 = 17.
(b) Characteristic times (Δt 1 – the time needed for
a vortex to move from one to another edge and
Δt2 – the nucleation period) as a function of the
magnetic field for a pinning center located at the
end of the vortex trajectory. (c) Bifurcation of vortex
trajectories. Distribution of |ψ| 2 for the tube with
radius R = 480 nm, length L = 3 μm at the transport
current density 17.14×10 9 A/m 2 and B = 10 mT.
Solid black and dotted lines represent available
vortex trajectories. The images (a) and (b) are taken
from R. O. Rezaev et al., Physica C 497, 1 (2014).
Imaging of buried 3D magnetic rolled-up nanomembranes: Increasing performance
and enabling novel functionalities of microelectronic devices, such as three-dimensional on-chip architectures in optics, electronics and magnetics, calls for new approaches
in both fabrication and characterization. Up to now, 3D magnetic architectures had mainly been studied by integral means, e.g. ferromagnetic resonance [15], anisotropic
magentoresistance [16, 17], and cantilever magnetometry [18]. However, optimization
of the performance of the magnetic 3D devices solely relies on precise tailoring of
the local magnetic microstructures, which can barely be retrieved from integral
Fig. 3: Utilizing the shadow contrast in transmission
XPEEM to visualize buried magnetic domain patterns
in 3D magnetic architectures such as magnetic
rolled-up nanomembranes with multiple windings.
Schematic of projecting the magnetization vector
field as a negative onto the planar substrate. XMCD
signal is taken from experiment. The transparent
non-magnetic outer layer hides the actual magnetic
domain patterns from direct observation. Signal
contributions from various layers can be identified.
The image is taken from R. Streubel et al., Nano Lett.
14, 3981 (2014).
measurements. This goal can only be achieved by directly visualizing the magnetic
domain patterns of the complex 3D object using magnetic imaging techniques relying
on magneto-optical Kerr effect [19, 20] or soft x-ray [20, 21] microscopies.
Very recently, we put forth the concept to visualize magnetization patterns in 3D magnetic objects based on an advanced analysis of the shadow contrast in X-ray magnetic
circular dichroism photoemission electron microscopy (XMCD-PEEM) accompanied by
the modeling of the XMCD contrast (Fig. 3) [21]. Although we exemplarily applied it to
image buried magnetic spirals prepared using rolled-up nanotechnology, the approach
can be generalized to magnetic objects of virtually any shape. We discriminated magnetic contributions from individual magnetic windings that provided means to derive the
switching behavior and to reconstruct the magnetization in each layer of the magnetic
spiral. Our concept can be extended to multi-component materials due to element
sensitivity of the XMCD-PEEM as well as to heterostructures of arbitrary shape. By
proper engineering the magnetic microstructures in these on-chip tubular architectures
potentially allows to enhance their magnetoresistive as well as magnetoimpedance
performance, which is relevant for prospective magnetoencephalography [22] and
memory devices [23].
Fig. 4: (a) The transferred microsensor array can
conform to the soft and curved surface of a fingertip. The inset shows a GMR microsensor transferred
to the receiving PDMS membrane uniaxially
pre-strained to 20%. GMR characteristics of
(b) Py/Cu and (e) Co/Cu GMR multilayers before
(black) and after (red) the transfer process.
(c) Electron microscopy images of a cut through the
transferred GMR film show the good adhesion of
the wrinkled magnetic nanomembrane to the PDMS
support. (d) A confocal microscopy image showing
the topology of the wrinkled GMR multilayer element. The image is taken from M Melzer et al., Adv.
Mat. doi: 10.1002/adma.201403998.
Direct transfer of magnetic sensor devices to elastomeric supports for stretchable
electronics: Electronics of tomorrow will be flexible or even stretchable and will form a
seamless link between soft, living beings and the digital world [24, 25]. The stretchability provides vast advantages over conventional rigid electronics particularly in
consumer electronics and medical implants, where large area, extreme thinness and compliance to curved surfaces are the key requirements for the devices [26, 27]. Introducing stretchable magneto-sensorics into the family of stretchable electronics is envisioned
to equip this novel electronic platform with magnetic functionalities [28-30].
Here, we introduced a novel fabrication platform for stretchable magneto-sensorics
relying on a single step direct transfer printing of thin functional elements from a rigid
donor substrate to a mechanically pre-stretched elastic membrane (Fig. 4) [31]. The
method offers numerous advantages in terms of miniaturization and level of complexity and allows transferring an entire microsensor array including contact structures in
a single step. Furthermore, relying on the new fabrication platform, we substantially
enhanced the stretchability of transferred GMR multilayer up to about 30 % relying
solely on the wrinkled topology and the meander geometry, without the formation of
cracks. The latter is of great importance as the senor elements introduced here are
truly strain invariant since without cracks almost no resistance change is associated with
the tensile deformation.
Applications of the proposed technology platform are far-reaching: the presented direct
transfer approach is not limited to magnetic nanomembranes, which renders possible
the combination of magnetoelectronic components with other stretchable functional
elements. In this way, smart multi-functional and interactive electronic systems can be
envisioned for imperceptible [26] and transient [27] electronics where the magnetoelectronic components can add a sense of orientation, displacement and touchless interaction.
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Funding: ERC Grant (#311529), Volkswagen Foundation (#86 362),
DFG Priority Programme 1726, BMBF-Russia research grant (#01DJ13009),
DFG Grant (#MA 5144/2-1), ERC Grant (#306277), BMBF project Nanett (German
Federal Ministry for Education and Research FKZ: 03IS2011O).
Cooperation: 1 IPF Dresden; 2 National Research Tomsk State University, Tomsk, Russia;
3
National Research Nuclear University MePhI, Moscow, Russia; 4 HZB, BESSY II;
5
Lawrence Berkeley National Laboratory; 6 Seoul National University;
7
Johannes Kepler University Linz
Research topic 2.4
Nanoscale magnets
People: J. Dreiser 2, A. Funk, Y. Ganushevich3, T. Greber 1, S. Gómez-Ruiz4, V. Hähnel, O. Hellwig5, E. Hey-Hawkins4,
L. Hozoi, D. Kasinathan10, V. Kataev, C. Konczak, J. Körner, D. Krylov, S. Kvashennikova3, V. Mehta5, V. Morozov 3,
O. Mosendz 5, T. Mühl, V. Neu, D. Pecko6, A. Petr, D. Pohl, A. A. Popov, C. Reiche, B. Rellinghaus, M. Richter,
J. Rusz 7, P. Schattschneider 9, H. Schlörb, O. G. Sinyashin3, C. Schlesier, S. Schneider, P. Tiemeijer 8,
S. Vock, D. Weller 5, R. Westerström1, S. Wicht, D. Yakhvarov 3, Y. Zhang, K. Zuzek-Rozman6
Summary: Nanoscale magnets range from single molecules to entities of a few million
atoms. Due to their inherently small size and their large surface-to-volume ratio, the
coupling of the magnetic cores to the local chemical environment significantly affects
their magnetic moments and anisotropies. Understanding and controlling the properties of such nanomagnets at different length scales is thus at the heart of this research
topic. The report reviews our work on nanoscale magnets in 2014. The materials related research on molecular magnets, magnetic nanoparticles and nanowires is complemented by efforts to develop novel methods and techniques which are particularly suited to characterizing magnetic materials at smallest possible length scales and
with ultimate resolution.
Molecular magnetism
Nitride cluster fullerenes are endohedral fullerenes with triangular M3N clusters (M = Sc,
Y, or lanthanides) encapsulated inside the carbon cage. In these molecular structures
different numbers of diamagnetic (DIA) and paramagnetic (PM) ions can be combined
in one cluster which allows to separate single ion properties from the influence of
interactions between lanthanide ions on the magnetic properties of such molecules. We
have studied the magnetic properties of GdxSc3−xN@C 80 (x = 1–3) as molecules with
isotropic magnetic ions [1]. For x = 1 the magnetization follows a Brillouin curve pointing to a negligible single ion anisotropy. For x = 1 and x = 2, however, the magnetization curves reveal ferromagnetic (FM) interactions between the Gd3+ ions with coupling
strength of -1.2 K and -0.6 K for x = 2 and x = 3, respectively.
DyxSc3−x N@C 80 (x = 1–3), on the other hand, exhibits single molecule magnet (SMM)
behaviour [2]. Here, the nitride ion in vicinity to the lanthanide results in a large
single-ion anisotropy with a uniaxial ligand field and an alignment of the magnetic
Fig. 1: Molecular structures of Dyx Sc3−x N@C 80 (x = 1–3) molecules (red arrows show
alignment of magnetic moments along Dy–N bonds) and corresponding magnetization
curves measured at 2 K.
moments along the lanthanide-nitrogen bond. As a result, DySc 2N@C 80 behaves as a
single-ion magnet with butterfly-shape hysteresis below 5 K (cf. Fig. 1). For x > 1,
exchange and dipolar interactions between the lanthanide ions strongly affect the
SMM properties. While in Dy2ScN@C 80, the FM coupling of Dy 3+ ions causes a broad hysteresis and large remanence, it leads to magnetic frustration and a narrow hysteresis
in Dy3N@C 80.
HoM2N@C 80 and Ho2MN@C 80 (with M = Sc, Lu, Y) were studied by NMR at room temperature [3]. Here, varying the radius of the DIA ions is found to cause a change of
both the magnetic anisotropy of the Ho3+ ions and the dynamics of the clusters in the
fullerene cages. In HoSc2N@C 80, also a single ion magnet behaviour was determined from
AC-SQUID studies [4], albeit on a much faster time scale than in DySc2N@C 80.
We have also synthesized the organonickel complex [NiBr(Mes)(phen)] (1) (Mes = 2,4,6trimethylphenyl, phen = 1,10-phenanthroline) and manipulated its magnetic properties
electrochemically [5]. Electroreduction allows to switch it from DIA to PM. Surprisingly, in the reduced complex, the spin density is mainly located at a ligand molecule
with a small leakage to the central metal ion rather than at the Ni-atom. Consequently,
_
electroreduction forms a spin-radical center phen · bound to the central Ni atom,
which has been monitored in-situ by ESR spectroscopy (cf. Fig. 2). The magnetic
_
anisotropy is enhanced with respect to the free phen · radical due to the partially unquenched orbital momentum of Ni, which could be beneficial for possible applications.
Magnetic Nanoparticles in Hard Disks
Granular L10 -ordered FePt films in combination with heat-assisted magnetic recording
(HAMR) are expected to soon replace CoCrPt perpendicular magnetic recording films
(PMR) and to provide areal storage densities (ADs) beyond 1.3 Tb/in2. To achieve this goal
the uniaxial anisotropy of L10 -FePt (6.6 MJ/m3 ) has to be fully developed in the grains
and the [001] easy axes have to be aligned perpendicular to the film plane. Seed layers
such as TiN, SrTiO3 or MgO are needed to provide for this texture.
Fig. 3: Cross-sectional HRTEM images of three granular FePt-C samples: a) reference sample
without Ar + ion etching, b) after 4 s and c) after 10 s of irradiation. The schematic drawings on
the right hand side illustrate the changes of (i) the particle morphology and structure and (ii)
the number and size of second-layer particles.
Fig. 2: Schematic view of the organonickel complex
with the phenspin-radical bound to the central Ni ion
(top), and the ESR spectrum evidencing the electrochemical generation of the bound spin center in the
molecule (bottom).
(a)
We have studied if and how Ar + irradiation of the MgO seed layers helps to improve the
FePt texture formation [6]. Structure and magnetic properties of the FePt-based media
are characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and vibrating sample magnetometry (VSM). We observe a flattening
of the MgO seed layer surfaces which goes along with a morphology change of the FePt
grains from spherical to island-type shapes (cf. Fig. 3). This is attributed to the reduced
number of nucleation sites for the FePt growth due to the smoothened seed layer surface. We also find an increased fraction of randomly oriented second layer particles and
an enhanced coalescence of the FePt primary grains. These structural changes result in
a reduced coercivity along the magnetic easy axis (out of plane) and an enhanced hard
axis (in plane) remanence. Notwithstanding to the increased amount of coalescence, δm
analysis of the magnetic interactions among the grains reveal weak dipolar couplings
indicating that even the sintered grains switch as individual magnetic entities and that
a treatment of the grain ensembles as Stoner-Wohlfarth systems is still permitted.
Magnetic Nanowires
(b)
One-dimensional, high aspect ratio nanoscaled magnets are prepared by electrodeposition within nanoporous templates. In recent years the focus was on iron based alloys
with specific magnetic properties such as Fe 80Ga20 showing high magnetostriction or
Fe 70Pd30 exhibiting a shape memory effect. Stable electrolytic baths have been achieved
by complexing the metallic components and the deposition mechanisms were investigated in detail in order to identify key deposition conditions for the reproducible preparation of homogeneous, defect free nanowires [7,8].
The as-deposited Fe 70Pd30 alloy exhibits a nanocrystalline bcc phase structure but can
be completely transformed to fcc as a starting point for MSM functionalization by high
temperature heat treatment and subsequent quenching. Modifying the electrolyte by
varying the Fe3+/SSC ratio (SSC: 5-sulfosalicylic acid, complexing agent) or addition of
Cu2+ have been shown to cause a change of the structure from bcc to fcc already during
deposition therefore avoiding any (unwanted) post-deposition annealing steps (cf.
Fig. 4).
Quantitative MFM
Fig. 4: Dependence of the FePd structure on (a)
the Fe 3+/SSC ratio and (b) the Cu 2+ ion concentration within the electrolyte composition.
Fig. 5: Probe design and corresponding modes
of operation: (a) geometrical structure,
(b) fundamental flexural mode for standard
perpendicular force gradient microscopy
(c) second flexural mode for lateral force
gradient microscopy, (d) – (f) SEM images of
a corresponding probe.
We developed and implemented a new measurement concept of quantitative bidirectional force gradient microscopy [9] that can be directly applied to quantitative magnetic
force microscopy. Quantitative force gradient measurements with cantilevers rely on the
knowledge of the corresponding dynamic spring constants of the force sensor. We
calculated such dynamic spring constants for two resonant oscillation modes, which
correspond to two orthogonal oscillation directions of the probe tip, taking the specific geometrical structure of our novel sensors into account (cf. Fig. 5). We proved the
applicability of the quantitative bidirectional force gradient microscopy by showing a
very good agreement between force gradient measurements based on magnetostatic
interactions and corresponding calculations. Furthermore, our measurement principle
relies solely on flexural vibrations. This is a strong practical advantage because all microscopy modes are based on vertical probe excitation and vertical deflection measurement only and can therefore be used with common dynamic scanning force microscopy
setups.
Magnetic dichroism with Electrons
Similar to XMCD, electron vortex beams (EVBs), which carry quantized orbital angular
momenta (OAM) L, allow to measure magnetic dichroism. Since electron beams can be
easily focused to sub-nanometer diameters, this technique provides for unrivalled
lateral resolution in magnetic measurements. In order to generate an EVB, specially
designed apertures are needed. However, the dichroic signals to be measured with
electron energy loss spectroscopy (EELS) are expected to be very small.
We have successfully implemented spiral- and fork-type apertures in the condenser
lens system of our FEI Titan3 80 -300 transmission electron microscope (TEM) equipped
with an image CS corrector. This setup allows to generate EVBs with user-selectable OAM
that can be used as probes in scanning TEM (STEM). While for spiral apertures, the
different OAM are dispersed along the beam direction, for fork-type apertures, they are
dispersed in planes perpendicular to the beam.
First investigations were focused on using spiral apertures, where the EVB is (de)focussed
to select the OAM. We have shown that the diameters of L = 0 and |L| = 1 probes are
0.14 nm and 0.3 nm, respectively (cf. Fig. 6 a/b). However, EELS did not provide any
evidence for dichroism in several samples, and simulations have shown that with spiral
apertures, the superposition of contributions from different OAM leads to an effective
cancellation of L at the sample position [10].
We have, however, found that by using fork-type apertures in combination with an
additional aperture in a modified condenser setup contributions from unwanted OAM
can be effectively blocked. First experiments on FePt nanocubes reveal very encouraging results with dichroic signals in EELS from atom-sized EVB.
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Funding: DFG: PO 1602/1-2, DFG: PE 771/4-1, DAAD project A/13/71281,
Leibniz Pakt-Projekt 2014, D-A-CH: DU225/31-1, HGST Joint Study Agreement.
Cooperation: 1Univ. Zürich, Switzerland; 2Paul Scherrer Institut, Villingen,
Switzerland; 3Arbuzov Institute of Organic and Physical Chemistry, Kazan, Russia;
4
Univ. Leipzig; 5HGST – A Western Digital Company, San Jose, CA, USA;
6
Jozef-Stefan Institute, Ljubljana; 7Univ. Uppsala, Sweden; 8FEI Company, Eindhoven,
The Netherlands; 9 TU Vienna, Austria; 10MPI for Chemical Physics of Solids, Dresden
Fig. 6: (a) Spiral type and (b) fork type vortex apertures to be inserted into the condenser system of a
transmission electron microscope. (c) Electron vortex
probes carrying orbital angular momenta of L = -1,
L = 0 and L = +1 as generated by using a spiral type
aperture. Probe diameters are roughly 0.14 nm
and 0.3 nm for L = 0 (central spot) and |L| = 1,
respectively.
Research Topic 2.5
Materials for energy efficiency, storage & conversion
People: S.-H. Baek, J. Deng, K. Eckert 2, A. Gebert, L. Giebeler, M. Graczyk-Zajac1, H. J. Grafe, F. Hammerath,
K. Hennig, M. Herklotz, T. Jaumann, F. Karnbach, M. Klose, S. Oswald, K. Pinkert, B. Rellinghaus,
R. Riedel1, L. M. Reinold1, A. Surrey, W. Si, M. Uhlemann, C. Yan, X. Yang 2, L. Zhang
Responsible Directors: B. Büchner, O. G. Schmidt, L. Schultz, J. Eckert
Summary: Relying on the existing possibilities at the IFW to cover the complete range
from developing a new material, its detailed characterization and its application in a
specific device, we aim at a concerted research activity in the field of energy conversion/storage/efficiency. This activity includes development and characterization
of materials for Li and Na batteries and capacitors as well as hydrogen production,
storage and (re)-conversion to electricity for application on different length scales. In
this report, we review our work in 2014, covering new insights into Li ion battery
materials and their Li ion mobility, as well as hydrogen generation and storage applications.
Lithium dynamics in carbon-rich polymer-derived SiCN ceramics probed
by nuclear magnetic resonance
The performance of a Li ion battery is determined, amongst other parameters, by the
Li diffusivity of its electrodes. A versatile tool to study the microscopic jump process of
the Li ions is nuclear magnetic resonance (NMR). By taking advantage of the available
solid-state NMR techniques at the IFW, we have determined the Li diffusion parameters
over a wide dynamic range in SiCN, a polymer-derived ceramic that possess novel
physical, chemical, and mechanical features which can be tuned by subtle changes of
composition and/or microstructure [1]. The slowest Li motion can be detected by
linewidth (FWHM) and spin-spin relaxation (T2 ) measurements of the 7Li nucleus. A
change in the slope of the temperature dependent FWHM and T2-1 indicate a crossover
from the motional narrowing (high temperature) to the rigid lattice regime (low temperature) which allows to determine the activation energy EA = 0.31 eV of the ionic hopping
process in SiCN. Further information about the faster Li motion on a timescale of μs can
be obtained by measuring the spin lattice relaxation rate T1-1 in different magnetic fields
and the rotating frame relaxation rate T1ρ-1. The temperature and frequency dependencies of the 7Li relaxation rates demonstrate that the Li dynamics in the polymer-derived
SiCN ceramics is governed by a stable thermal activation law opening the possibility to
fine-tune the Li diffusion parameters for specific battery performance.
Fig. 1: Properties of the
nanoparticulate Si anode.
Hollow silicon nanocomposites synthesized through economical chemistry
as high performance anode in Li – ion batteries
Li – ion batteries are the first choice for many portable electronic devices owing to its
high energy density and excellent rechargeability. Tougher requirements especially for
mobile applications requires higher energy densities which can only be achieved by the
development of high-capacity electrode materials [2]. Silicon is a promising candidate
to replace graphite as commonly used anode with up to 10 times higher capacities owing to an alloying process of lithium with silicon. However, the large volume expansion
of silicon during lithiation causes high stress inside the particles triggering crack
propagation of individual particles causing a low cycle stability of silicon-based anodes
[3]. We developed a stable silicon anode with a high capacity of up to 2000 mAh/gSi
(theoretical capacity of graphite = 372 mAh/g) which can be cycled for more than 1000
times with retaining 60 % of its capacity [4,5]. We attribute the exceptional performance
to ultra-small silicon nanoparticles (< 5 nm) which do not undergo crack propagation
and, even more important, form a stabilized solid-electrolyte-interface owing to its high
surface energy. Additionally, a well-designed carbon cage allows good interfacial electron transfer turning the composite into a high-performance anode material. We first
form a precursor through simple polycondensation of high versatile and cheap
trichlorosilane with water in the presence of a surfactant followed by a temperature treatment, carbonization and an etching procedure. Current research is ongoing to optimize
the silicon anode for next generation Li – sulfur batteries and to investigate structural
phenomena inside the silicon anode.
Nanomembranes for energy storage in lithium ion batteries
at the macro-/microscale
Rolled-up nanotechnology offers an advanced strategy to deterministically rearrange
two-dimensional nanomembranes into novel micro-/nanostructures for energy storage applications. Based on this technology and our previous works, we further demonstrate a hierarchical electrode design with just one material SiOx for distinct
functionalities by controlling the oxygen content x in each layer [6]. The resulted
SiOx (x ∼ 1.85)/SiOy ( y ∼ 0.5) bilayer nanomembranes as anodes exhibit a reversible
capacity of about 1300 mAh/g at a current rate of 100 mA/g, an excellent stability of
over 100 cycles, as well as a good rate capability (see Fig. 2(a)). Even after a deep
cycling of 180 cycles at different current densities, the reversible capacity can recover
completely to the original value at 100 mA/g. This excellent performance is due
largely to the fast ionic transport, powerful strain accommodation and synergistic effect
a)
b)
Fig. 2: (a) Cycling performance of both rolled-up silicon-rich monolayer and hierarchical bilayer
measured at 100 mA/g for 60 cycles. (b) Schematic of an encapsulated Li-ion battery with a
single silicon tube as the anode.
of oxygen-rich SiOx layer and silicon-rich SiOy layer. In order to perform a deep investigation of the electrochemical kinetics, an elegant lab-on-chip electrochemical device
based on a single rolled-up Si tube is fabricated in our lab (see Fig. 2 (b)). Working as
the anode in Li-ion batteries, the single tube exhibits enhanced diffusion in comparison to the planar film. After three charge/discharge cycles, the tube presents a wrinkled
structure due to strain induced local deformation, which could be exploited to maintain
a stable cycling and is consistent with the electrochemical performance of bulk electrodes [7]. This single tube device could be used as a promising ultra-microelectrode
for other kinetic research, and an integrated full device could be developed as a local
energy supply for powering ultra-compact microsystems.
Magnetic field-driven enhancement of hydrogen production
in water electrolysis
The change in the German Energy Policy makes it necessary to develop novel methods
for energy storage to buffer the differences between production and consumption. A
highly promising way is the production of high-purity hydrogen via alkaline water
electrolysis. Recently, it was shown that the efficiency of hydrogen production on planar electrodes was increased by the application of homogeneous magnetic fields normal
to the electrode surface. This leads to a decrease of the bubble size and increase of
the bubble release frequency and efficiency caused by magnetically induced electrolyte
convections, so called magneto-hydrodynamic effect (MHD) [8]. To get a detailed understanding of the interaction of the electrolyte flow fields with the mechanism of bubble
nucleation, growth and detachment, the hydrogen evolution on circular platinum microelectrodes under the influence of homogeneous and inhomogeneous magnetic field is
studied at a specifically developed electrochemical setup. The process of bubble detachment is visualized with a CCD-camera and the velocity fields are analyzed by particle
image velocimetry (PIV).
Simulations on in-situ HRTEM of nanosized MgH2 at pressures of 1 bar H2
Nanostructuring of hydrides has been shown to reveal improved thermodynamic and
kinetic properties, which are strongly needed for application of solid-state hydrogen
storage materials. However, most hydride phases such as MgH2 cannot be studied at highest resolution by means of TEM, because of fast degradation upon irradiation with the
imaging electron beam. This can be overcome using a novel nanoreactor (see Fig. 3 (a))
recently developed by H. Zandbergen (TU Delft). It allows for in-situ TEM studies at
elevated hydrogen pressures (up to 4.5bar) and temperatures (up to 500°C). A point
resolution of 1.8 Å has already been demonstrated experimentally for Cu nanocrystals.
b)
Fig. 3: (a) Schematic illustration of the simulated supercell representing the nanoreactor. 20 nm
thick electron transparent windows composed of amorphous SiN at the top and the bottom of
the nanoreactor encapsulate the hydrogen gas. The MgH2 nanocrystal is placed on the bottom
window. (b) Simulated HRTEM image of a 12 nm thick MgH2 nanocrystal in [110] orientation
inside the nanoreactor. Blue circles represent Mg atoms and orange circles hydrogen atoms.
We study the feasibility of HRTEM investigations of light weight metals such as Mg and
its hydride phase with the nanoreactor by means of multi-slice HRTEM contrast simulations. Such a setup allows to fundamentally study the dehydrogenation and hydrogenation reactions at the nanoscale. We analyze the dependence of both spatial resolution
and image contrast on parameters such as the defocus, metal/hydride thickness, hydrogen pressure and nanoreactor geometry to explore the possibilities and limitations of
in-situ experiments with this reactor. Our simulations show that even for thicknesses
down to 4.5 nm MgH2, atomic resolution of the crystalline specimens can be obtained.
Exemplarily, the simulated HRTEM image of a 12 nm thick MgH2 nanocrystal in [110] zone
axis orientation is shown in Fig. 3 (b). The atomic structure is clearly visible even in the
presence of the top and bottom SiN window and an atmosphere of 1 bar H2. The resolution is high enough to resolve neighboring Mg atom columns, which are separated by
only 1.5 Å. Such simulations may be highly valuable to pre-evaluate future experiments and to design future nanoreactors.
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
S.-H. Baek et al. Journal of Power Sources 253 (2013) 342.
P.G. Bruce et al. Nature Mater.11 (2012) 19.
C.-M. Park et al. Chem. Soc. Rev. 39 (2010) 3115.
T. Jaumann et al. Chem. Mater. 10.1021/cm502520y (2014).
T. Jaumann et al. Patent Appl. 2014.
L. Zhang et al. Adv. Mater. 26 (2014) 4527.
W. Si et al. Adv. Mater. 26 (2014) 7973.
J.A. Koza et al. Electrochim. Acta 56 (2011) 2665.
Cooperation: 1 Technische Universität Darmstadt, Fraunhofer IWS Dresden,
Technische Universität Dresden, Universität der Bundeswehr München
2
Funding: DFG priority program SPP1473), BMBF, WING Center – Excellent battery:
Batterie - Mobil in Sachsen (BaMoSa), DFG International Research Training Group (IRTG)
Leibniz Pakt project
Research Area 3 QUANTUM EFFECTS AT THE NANOSCALE 51
Research Topic 3.1
Designed interfaces and heterostructures
People: L. Alff 3, K. Duschek, S. Fähler, J. Geck, E. Di Gennaro1, J. E. Hamann-Borrero, F. He5, N. Heming, R. Hentrich,
R. Hühne, M. Knupfer, A. Koitzsch, P. Komissinskiy3, S. Krause2, K. Leistner, S. Macke4, F. Miletto Granozio1, A. Petr,
G. A. Sawatzky6, H. Schlörb, U. Scotti di Uccio1, R. Sutarto5, U. Treske, M. Uhlemann, M. Vafaee3, M. Zwiebler
Summary: With the advent of advanced deposition techniques like pulsed laser
deposition and molecular beam epitaxy it became possible to control the production
of thin films and heterostructures on a level of atomic layers, thereby shifting genuine
interface effects in the focus of scientific interest.
Interfaces between certain complex oxides have attracted enormous attention due
to the occurrence of unexpected phenomena, most notably the metallic conductivity
between wide gap insulators [1]. Moreover superconductivity and magnetism have been
observed [2, 3] and a variety of interface states with magnetical and orbital reconstructions not stable in the bulk materials [4, 5]. These findings raise both: the prospect
of stabilizing even more exotic ground states at tailored interfaces and to exploit such
effects in all-oxide devices. Beyond stabilizing interesting new states, a tuning of
interface states is pursued by studying potential dependent phenomena at the
metal/electrolyte interface [6]. This approach opens the way to electric field control
of magnetism in metals at room temperature - exciting for potential use in multifunctional nanosystems and magnetic data storage.
In the following we will concentrate on three examples of ongoing research activities in
the IFW concerning the interfaces between LaAlO3 and SrTiO3 and closely related
materials, the properties of LaSrMnO4 thin films on a NdGaO3 substrate and the electric
field control of magnetism at an electrode/electrolyte interface.
1. Polar heterointerfaces
The LaAlO3 /SrTiO3 interface has been heavily studied during the last decade after the
discovery of the insulator metal phase transition as a function of LaAlO3 layer number.
However, no consensus has been reached regarding the actual physical mechanism
52 Research Area 3 QUANTUM EFFECTS AT THE NANOSCALE
triggering the phase transition. Although the so called “polar catastrophe” scenario,
where the metallic state is a consequence of an electronic reconstruction alleviating
growing internal electrostatic potentials in the overlayer, elegantly explains many experimental observations, it is steadily contested by scenarios involving point defects,
such as oxygen vacancies. Our ansatz was to broaden the perspective by taking into
account the isostructural and isovalent NdGaO3 /SrTiO3 and LaGaO3 /SrTiO3 systems,
which all show an insulator-to-metal transition as a function of the overlayer thickness.
The difference is the lattice mismatch between the SrTiO3 substrate and the overlayer
material, which is largest for LaAlO3 and smallest for LaGaO3. We investigated the electronic properties of NdGaO3 /SrTiO3, LaGaO3 /SrTiO3, and LaAlO3 /SrTiO3 in a comparative
study based on X-ray absorption spectroscopy, X-ray photoemission spectroscopy and
resonant photoemission spectroscopy. Furthermore, LaVO3 /SrTiO3 interfaces were
prepared for future investigations exhibiting a similar sharp insulator-metal phase
transition at 6 monolayers.
First the nature of the charge carriers, their concentration and spatial distribution
have been studied and quantitatively evaluated. The charge carriers are of Ti 3d character and the 2-dimensional sheet carrier density has a lower boundary in the range of
0.8 – 1.5 x 1014 cm-2 in reasonable agreement with Hall conductivity data. The extension
of the charged near interface region must be at least 2 nm. Fig. 1 shows a compilation
of the peak width of several core levels divided into substrate and overlayer excitations.
Fig. 1: Full width half maximum
(FWHM) of substrat and overlayer
core levels.
Fig. 2: Band diagram of polar
heterostructures derived on the
basis of photoemission data.
Fig. 3: Structure of an LaSrMnO4 film on an NdGaO3 substrate.
Clearly the overlayer lines have a tendency to decrease with layer number. This is not
expected for the polar catastrophe model: the increasing electrostatic potentials would
cause a line broadening. On the other hand a broadening is observed for the SrTiO3 lines.
From this and other measurements (exploiting the peak positions) a band diagram
could be extracted (Fig. 2).
The behavior of the three analyzed heterostructures is found to be remarkably similar.
The valence band edge of all the three overlayers aligns to that of bulk SrTiO3. The conduction band offset differs due to the different gap values among the materials. The nearinterface SrTiO3 layer is affected, at increasing overlayer thickness, by the building-up
of a confining potential. This potential bends downwards both the valence and the conduction band, the latter one crossing the Fermi energy in the proximity of the interface,
and determines the formation of an interfacial band offset growing as a function of
thickness. In this way a metallic interface region emerges. Quite remarkably, but in agreement with previous reports for LaAlO3 /SrTiO3, no electric field is detected inside any of
the polar overlayers. Especially the last point poses a serious obstacle for the polar
catastrophe model in its original form. A possible way to circumvent this problem is the
assumption that oxygen vacancies are created during the film growth and the subsequent
charge transfer balances internal fields.
2. Manganate layers
For interfaces and thin layers the determination of important structural information such
as interface terminations and stacking of atomic layers is often difficult. Here a scheme
based on resonant x-ray reflectivity measurements is developed which is capable to
provide such information with atomic resolution. Using LaSrMnO4 as an example the
theoretical and experimental implications of this approach are explored.
In simple words, the reflectivity is given by interference of x-rays that are reflected at
the different interfaces realized in an artificial heterostructure. Referring to the reflection of optical light, an interface can be defined as a region in space where there is a
change of the refractive index n. Similarly, also in the x-ray range even a small change
in n will introduce an interface, thus a traveling x-ray wave will be reflected. This high
interface sensitivity is what allows to accurately determine structural properties of
heterostructures such as layer thicknesses and interface roughnesses by means of x-ray
reflectivity. Going one step further at synchrotron light sources the reflectivity can be
studied by tuning the x-ray photon energies to an absorption edge. At these so-called
resonant energies, the refractive index depends very strongly on the valence shell
configuration of the resonant scattering centers and, hence, the sensitivity to spatial
variations of the electronic properties is dramatically enhanced at resonances.
By quantitatively modelling experimental reflectivity data of LaSrMnO4 we obtained
detailed information of the film structure as exemplified in Fig. 3. Resonant x-ray
scattering will be a powerful tool for the investigation of a broad class of artificial
heterostructures.
3. Electric field control of magnetism at the electrode/electrolyte interface
Electric control of magnetism is a vision which drives intense research on magnetic semiconductors and multiferroics. Recently, also ultrathin metallic films were reported to
show magnetoelectric effects at room temperature [6]. We study electric field induced
changes of magnetism at the electrode/electrolyte interface. This approach allows to
exploit potential dependent electrode processes as double layer charging, and/or
faradaic reactions to control the surface magnetism. We achieved significant changes
of anisotropy, coercivity and magnetization in FePt and CoPt. For Fe films, faradaic
reactions involving Fe and iron oxide have been investigated and a reversible in- and
decrease of saturation magnetization up to 64 % was achieved (Fig. 4). This opens the
way to voltage controlled “on/off ” nanomagnets. In a next step such a switchable surface Fe layer has been combined with a textured hard magnetic FePt layer. In this case,
by exchange coupling through the interface, voltage control of the overall spin
orientation has been achieved.
Fig. 4: Voltage induced change of magnetization
in Fe films probed by in situ Anomalous Hall Effect
measurements.
[1]
[2]
[3]
[4]
[5]
[6]
A. Ohtomo et al., Nature 427, 423 (2004)
N. Reyren et al., Science 317, 1196 (2007)
A. Brinkman et al., Nature Materials 6, 493 (2007)
J. Chakhalian et al., Science 318, 1114 (2007)
A. Tebano et al., Phys. Rev. Lett. 100, 137401 (2008)
M. Weisheit et al., Science. 315, 349 (2007)
Funding: DFG Emmy Noether Program, DFG Eigene Stelle
Cooperations: 1 Univ. Naples, Italy; 2 BESSY, Berlin, Germany; 3 Univ. Darmstadt,
Germany; 4 UBC Center, Vancouver, Canada; 5 Canadian Light Source, Saskatoon,
Canada; 6 Univ. British Colombia, Canada
Research topic 3.2
Self-organised electronic order at the nanoscale
Authors: J. Geck, T. Ritschel, J. Trinckauf, K. Koepernik, M. Daghofer, L. Hozoi, S-H. Baek, D. V. Efremov, R. Ganesh,
S. Sykora, P. Abbamonte1, H. Berger 2, J. J. Betouras3, X. M. Chen1, T. C. Chiang1, A. V. Chubukov 4, S. L. Cooper 1,
K. D. Finkelstein5, E. Fradkin1, Y. Gan1, G. Garbarino6, P. Ghaemi 1, M. Hanfland 6, D. G. Hawthorn7, F. He8, Y. I. Joe1,
M. Kawasaki 9, J. S. Kim10, J. C. T. Lee1, G. J. MacDougall1, M. Nakamura9, J. M. Ok10, G. A. de la Peña1,
G. A. Sawatzky11, E. Schierle12, R. Sutarto11, Y. Tokura9, H. Wadati 13, S. Yuan1, M. v. Zimmermann14
People involved: D. Baumann, C. Blum, S.-L. Drechsler, D. V. Efremov, H.-J. Grafe, C. Hess, R. Hübel,
M. Knupfer, M. Kusch, S. Leger, U. Roessler, F. Steckel, S. Sykora, S. Wurmehl, M. Zwiebler
Responsible Directors: B. Büchner, J. van den Brink
Summary: The objective of this research focus is to investigate self-organization
phenomena in complex electron systems with pronounced electron-electron and
electron-phonon interactions. The large families of transition metal oxides and transition metal dichalcogenides as well as the iron pnictides provide prime examples for
materials, which realize such electron systems and which are also studied here. The
present research effort takes great profit from the unique combination of complementary methods available at the IFW Dresden and as such merges state-of-the-art
theoretical methods with leading-edge experiments. In this report, we focus on a specific highlight of our work in 2014, namely the relation between superconductivity
and electronic order in real space as well as the emergence of complex orbital textures
in transition metal dichalcogenides.
A great variety of interacting electron systems spontaneously form intrinsic electronic
nanostructures, typically driven by strong electron-electron and electron-phonon
interactions. The microscopic structure of such an electronic order is therefore a direct
fingerprint of the relevant interactions in a system as well as the involved degrees of
freedom. In addition to this, self-organized electronic orders are intensively discussed
in relation to the most fascinating electronic phenomena we know today, like unconventional superconductivity, colossal magnetoresistance, strong magnetoelectric
couplings or quantum criticality.
A strong motivation for the study of self-organized electronic orders is therefore to
unravel the microscopic physics behind these phenomena. This is not only of great
interes t for basic research. It also bears relevance for applied science, since the
understanding of the microscopic mechanisms at work may also show up routes towards
new technological applications. It is also very important to point out that recent advances
in experiment and theory nowadays make it possible to probe, manipulate and analyze
these electronic ordering phenomena in unprecedented detail. A famous case in point
here are the magnetic skyrmions, which were first predicted by theory, then observed
by momentum resolved experiments and, just in 2013, manipulated using spatially
resolved scanning microscopes.
Notwithstanding these recent breakthroughs, we are only beginning to understand
electronic order in complex materials and many important aspects still remain to be
explored. Within this research topic we merge the unique expertise of the IFW in materials preparation (bulk, thin films, heterostructures and lateral nanostructures), experimental characterization (thermodynamics, scanning probes, x-ray spectroscopies, x-ray
scattering, photoemission) and theoretical modeling (ab initio and model-based) into
one coherent research effort. Central aim is to understand the coupling between electronic ordering in real space on the one hand and the electronic structure on the other
hand. In this way, the present topic builds a bridge from fundamental research towards
applications. The activities within this research focus are also part of the new Collaborative Research Center in Dresden (SFB 1143) and the Graduate School (GRK 1621) at the
Technical University of Dresden.
During 2014, a number of complex electron systems displaying unconventional types of
electronic order have been investigated, including iron pnictides [1], uranium-based
heavy fermion compounds [2], bulk and nanostructures of transition metal oxides [3]
and various transition metal dichalcogenides [4]. In this report, however, we will focus
on new results regarding the electronic order in 1T-TaS2 and 1T-TiSe2, which illustrate
how the strategy for this research focus has already put into practice
1T-TaS2 and 1T-TiSe2 exhibit a number of charge density wave (CDW) phenomena that
attract considerable attention, in particular because these electronic orderings occur in
close proximity to superconductivity (SC). In fact, we found strong evidence that defects
within the electronic superlattice formed by the CDW are essential to create superconductivity: Using high-pressure X-ray diffraction (XRD) experiments, we discovered a
superconducting electronic crystal in 1T-TaS2 that is characterized by a long-range
order of solitonic defects within a CDW-superlattice.
Fig. 1: Pressure–temperature phase diagram of
1T-TiSe 2. a) Broad phase diagram showing CDW
ordered, normal state and superconducting phase
boundaries. The green color scale indicates the
integrated intensity of CDW peaks, including both
the C and IC components. The superconducting TC,
has been exaggerated by a factor of five for visibility.
Points where the precise commensurability was
measured are labelled C, I or C/I, indicating
commensurate, incommensurate or coexistence,
respectively. Ordered CDW-defects occur within
the I-phase. b) Zoom-in on the region exhibiting the
transition between commensurate and incommensurate order (grey dashed rectangle in a). From Ref. 5.
To better understand the connection between SC and such defects, we extended our
investigations and used high-pressure XRD to directly study the CDW order in 1T-TiSe2
[5], which was previously shown to exhibit SC when the CDW is suppressed by pressure
or intercalation of Cu atoms. As shown by the phase diagram in Fig. 1, we succeeded in
suppressing the CDW fully to zero temperature, establishing for the first time the existence of a quantum critical point at Pc = 5.1 ± 0.2 GPa, which is more than 1 GPa beyond
the end of the superconducting region. Unexpectedly, at P = 3 GPa we observed a reentrant, weakly first order, incommensurate phase, indicating the presence of a Lifshitz
tricritical point somewhere above the superconducting dome. This study suggests that
superconductivity in 1T-TiSe2 is not connected to the quantum critical point itself. It
rather further supports the notion that the formation of defects within the CDW order
plays an important role for SC in the transition metal dichalcogenides.
In a very recent work, also done during 2014, we further found that CDW order in transition metal dichalcogenides does not only involve charge modulations. Instead we revealed a remarkable and surprising new feature of CDWs, namely their intimate relation
to orbital order. Combining state-of-the-art density functional theory with leading-edge
x-ray scattering and photoemission experiments, we not only showed that the CDW of
1T-TaS2 within the two-dimensional TaS2 -layers involves previously unidentified orbital
textures of great complexity. We also demonstrated that two metastable stackings of the
orbitally ordered layers allow manipulating salient features of the electronic structure.
As can be seen in Fig. 2, for both metastable stackings a complex orbital texture within the ab-plane emerges. Note that not only the occupancy of a certain type of orbital
changes spatially, but also the symmetry of the orbitals clearly changes from site to site,
resulting in a complex orbital ordering pattern. For instance, whereas the orbital is
oriented perpendicular to the ab-plane at the center of a Ta-cluster, a significant inplane component exists at the cluster edges. It is also worth mentioning that the in-plane
orientation of some orbitals changes as a function of the c-axis stacking and that also
the S 3p-states take part in the orbital texture.
Fig. 2: Real space illustration of the electron density for the highest occupied band of the
CDW phase of 1T-TaS2. (a), (b): A complex orbital texture emerges within the ab-plane.
(c): The 1c-stacking allows for significant hopping only along the c-direction.
(d): A substantial ab-component of the hopping appears for the 2a+ c-stacking,
which is metastable with the 1c stacking in (c).
The orbital stacking illustrated in Figs. 2(a,c) permits significant charge hopping only
along c. In other words, the charges flow along orbital stripes along c, corresponding
to the quasi one-dimensional character of the uppermost band close to the Fermi level.
This drastically changes in the case of the stacking shown in Figs. 2(b,d). Now there
is a significant ab-component of the hopping, so that the uppermost band attains a
larger in-plane dispersion and crosses the Fermi level along Γ-M and Γ-K (not shown).
Based on these new insights from basic research, a new device concept has been
developed, which we termed orbitronics. The orbital effects described above enable to
switch the properties of 1T-TaS2 nanostructures from metallic to semiconducting with
technologically pertinent gaps of the order of 200 meV, as shown in Fig. 3 for a 1T-TaS2
bilayer. This new type of orbitronics is a good example of how basic research can lead to
new technological concepts, which is especially relevant for the ongoing development
of novel, miniaturized and ultra-fast devices based on layered transition metal dichalcogenides.
[1]
[2]
[3]
[4]
[5]
S.-H. Baek et al., Nature Materials, advance online publication (2014)
A.V. Chubukov et al., Phys. Rev. Lett. 112, 037202 (2014)
H. Wadati et al., New Journal of Physics 16, 33006 (2014)
R. Ganesh et al., Phys. Rev. Lett. 113, 177001(2014)
Y. I. Joe et al., Nature Physics 10, 421 (2014)
Funding: Deutsche Forschungsgemeinschaft
Cooperations: 1Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, USA; 2Ecole Polytechnique Federale de Lausanne,
Switzerland; 3Department of Physics, Loughborough University, United Kingdom;
4
Department of Physics, University of Wisconsin-Madison, USA; 5Cornell High Energy
Synchrotron Source, Cornell University, Ithaca, USA; 6European Synchrotron
Radiation Facility (ESRF) Grenoble, France; 7Department of Physics and Astronomy,
University of Waterloo, Ontario, Canada; 8Canadian Light Source, University of
Saskatchewan, Canada; 9RIKEN Center for Emergent Matter Science (CEMS), Japan;
10
Department of Physics, Pohang University of Science and Technology, Korea;
11
Department of Physics and Astronomy, University of British Columbia, Vancouver,
Canada; 12Helmholtz-Zentrum Berlin für Materialien und Energie, Germany;
13
Department of Applied Physics and Quantum-Phase Electronics Center (QPEC),
University of Tokyo, Hongo, Japan; 14Deutsches Elektronensynchrotron (DESY),
Hamburg, Germany
Fig. 3: Device concept based on the switching
between metastable orbital orders. Calculated band
structure for a bilayer of 1T-TaS 2 with 1c-stacking (a)
and 2a + c-stacking (b). A semiconductor-to-metal
transition takes place upon changing the stacking of
the two layers. (c): Orbital order corresponding to
the semiconducting (top) and metallic state (bottom).
Research topic 3.3
Quantum and nano-photonics
Authors: S. Böttner, Y. Chen, F. Ding, S. Giudicatti, B. Höfer, Y. Huo, M. R. Jorgensen,
A. Madani, S. M. Marz, E. Zallo, J. Zhang, M. Zopf
People involved: R. Hühne, M. Mietschke, C. Ortix
Responsible Directors: O. G. Schmidt, L. Schultz, J. van den Brink
Summary: Next-generation photonic devices will rely on an ever increasing ability to
route, trap, and otherwise manipulate light under tight tolerances. For example a
precise control of the light emission wavelength is vital for the applications of single
or entangled photons in quantum information sciences. Another example is the
enhanced light-matter coupling in an optical resonator with tailored light trapping,
which is central to a variety of exciting optoelectronic device concepts. In this context
we have developed nanomembrane based technologies to manipulate light at microand nanoscales. Two photonic devices from our most recent progresses will be discussed
in this review. The first is an on-demand and wavelength tunable single photon source,
based on the light-hole emission from GaAs quantum dots embedded in a strain
engineered membrane. The second is a microtube resonator fabricated with rolled-up
titania nanomembranes, which has an optical resonance in the visible range.
Manipulation of light with nanomembrane technologies
Part I: Self-assembled quantum dot (QD) based SPSs are one of the promising candidates
for photonic quantum interface applications, with which the polarization state of
single photons and the electron spin states can be coherently interconverted. By employing the large discrepancy between the g-factors of electrons and light holes (LHs)
confined in a semiconductor QD, it is possible to realize bidirectional interconversion
between the states of single stationary (spin) and flying qubits (photon).
We reported on-demand and wavelength-tunable LH single-photon emission from tensile-strained GaAs QDs embedded in nanomembranes [1]. The former property confirms
the zero-dimensional character of our emitters, while the latter allows interfacing
different QDs for remote entangling electron-spins. First we present the experimental
methods of generating LH emissions from GaAs QDs. Then we demonstrate triggered LH
single-photon emission in the second-order time correlation measurements. We also
show that the emission wavelength of LH single photons can be dynamically and precisely tuned in a wide range by means of an externally-induced strain field.
The sample studied in this work consists of GaAs/AlGaAs QD heterostructure embedded
in two pre-stressed InAlGaAs layers, and was grown by solid-source molecular beam
epitaxy (MBE). It includes a 140 nm-thick QD-containing nanomembrane on top of a
100 nm-thick Al 0.75Ga 0.25 As sacrificial layer. In situ Ga droplet etching was used to
grow GaAs QDs in Al x Ga1-x As barriers (dot density < 108 cm-2 ). In particular, the sample
structure was designed in such a way that GaAs/Al xGa1 -x As QDs layer is sandwiched
between a pair of 20 nm-thick In 0.2 Al 0.4 Ga 0.4 As stressor layers. After removal of the
sacrificial layer in diluted HF solution, the compressed stressor layers expand inducing
an in-plane (xy plane) biaxial tension of about 0.4 % to the GaAs QDs. This feature
results in the switching of the hole GS from a dominant HH character to a dominant LH
character [1]. Thereafter, the free-standing QDs nanomembranes were transferred
onto a 200 μm-thick piezoelectric crystal [Pb (Mg1/3Nb2/3)O3]0.72[PbTiO3]0.28
(PMN-PT) via Au-to-Au thermo-compressive bonding as illustrated in Fig. 1a. When an
electric field Fp ( //z) is applied to the PMN-PT, an in-plane biaxial stress field from the
PMN-PT actuator is applied to the QDs nanomembranes. This allows for a precise tuning
to the emission wavelength of single photons emitted by the LH-excitons, see the
upper inset of Fig. 1b
Of most interest is the pulsed optical operation of our device. This allows controlling the
time of generation of excitons, and thereby realizing triggered LH single-photon emission. In order to achieve this, the diode laser is used to drive the QDs and meanwhile
the second-order time correlation function is measured under pulsed excitation. The
lower inset of Fig. 1b shows the unnormalized autocorrelation function of the in-plane
polarized exciton emissions, and the quantum nature of LH single-photon emission is
revealed by the significantly suppressed peak at zero-time delay. In addition, periodic
peaks in the autocorrelation measurement are observed. This is an unambiguous signature of a triggered LH single-photon emission. The temporal distance between these
peaks is found 12.5 ns, which is consistent with the excitation repetition rate of the diode
laser, 80 MHz.
One of the most important elements for a LH-based reversible quantum interface is a
‘tuning knob’ for the ground state energy levels of different QDs, which facilitates the
direct state transfer from the photon qubit emitted by one QD to the electron qubit in
another QD. Such a tunability is demonstrated with our LH QDs in Fig. 1b. A non-zero
Fig. 1: (a) A sketch of the nanomembrane-based
strain-tunable LH emissions. The GaAs nanomembrane including GaAs QDs integrated onto a piezoelectric crystal, in which the strain field can modify
the emission energy of photons emitted from the
QDs. (b) Wavelength tuning of the LH single-photon
emission as a function of Fp. A positive (negative)
electric field corresponds to a compressive (tensile)
strain field. The lower inset shows an autocorrelation
measurement.
electric field Fp is applied to the PMN-PT actuator to generate an in-plane strain field on
the QDs and a series of PL spectra from the QD are recorded as a function of Fp. Compared
to the emission wavelength at Fp = 0 kV/cm, the LH single-photon emission can be blueshifted (red-shifted) when a positive (negative) electric filed is applied. The total wavelength has been tuned by 3 nm (6 meV in energy) as Fp is varied from -20 to 40 kV/cm.
These results indicate that the optical properties of our LH single photon source can
be accurately tuned, and stable single-photon emission during the tuning process is
preserved.
Part II: Recently vertically rolled-up microcavities (VRUMs), as a novel form of whispering gallery mode (WGM) resonators, have attracted great interest and accordingly
opened up several attractive applications thanks to advances in rolled-up nanotechnology. Key features of VRUMs include the capability of on-chip fabrication, the hollow
core structure, and their ultrathin walls, which facilitate a highly penetrating evanescent wave sensitive to changes in the ambient refractive index. Depending on conditions,
VRUMs can be structurally robust enough to be transferred onto foreign substrates. For
these reasons, VRUMs are promising candidates for specialized tasks in integrated
optics, optoelectronics, and lab-on-a-chip applications. Recently, we reported the
inclusion of titania into the pallet of materials available for VRUMs.[3] Titania, as a
material, is an excellent candidate for optical devices due to its high refractive index
while maintaining transparency through the visible. In combination with the fabrication
strategies available using rolled-up nanotechnology, a wealth of optical structures with
improved properties is possible. However, titania is still new to rolled-up nanotechnology and a considerable amount of effort has been required to optimize processes for
this material.
Fig. 2: (a – c) SEM images showing rolled-up TiO2
tubes using square, circular and U-shape patterns.
In all the cases, titania membranes deposited at
room temperature were rolled using a photoresist
sacrificial layer. (d–f) Dependence of the tubes
diameter on the titania membrane thickness for
the different patterns presented in panels (a–c).
We presented a systematic work on the fabrication and characterization of titania
microtubes as an active material for different potential applications.[4] We showed how
titania microtubes can be rolled up using different sacrificial layers and discussed the
possibility of controlling not only geometrical characteristics but also the physical
properties such as the crystalline phase. The structural and optical properties of titania
deposited under different deposition conditions were investigated on single titania
membranes deposited on silicon substrates.
Titania microtubes can be successfully rolled up starting from different shapes and sizes
of the pattern, for example square, circular and U-shape masks (Fig. 2). The square and
circular patterns usually result in a higher yield (close to 100%) as previously reported
for SiO2. On the other hand, the U-shape offers interesting opportunities in the design
of optical resonators, since it avoids light leakage where the center of the tube is lifted
from the substrate and facilitates axial confinement of light.
Optical characterization of resonant modes at telecom wavelengths was performed on
U-shaped titania VRUMs by interfacing with a tapered fiber. Polarized light from a tunable IR laser was coupled into the fiber, and subsequently into the VRUM. Resonant modes
are manifested by a sharp decrease in transmission through the fiber. By scanning the
position of the fiber along the tube axis, controlling the angle that the fiber intersects
the tube, and varying the polarization through the fiber, the coupling can be optimized.
Figure 3 shows a representative transmission signal from a titania VRUM rolled-up from
a U-shaped pattern following optimization of fiber coupling. Fiber coupling can be
extended to create polarization-resolve mode maps that provide insight into the nature
of light-matter interactions within rolled-up resonators. These experiments have been
done in detail on HfO2 coated silica tubes, leading to the observation of new optical
modes as well opening the door to interesting utilizations.[5, 6]
Fig. 3: Normalized fiber transmission signal while
coupled to the center lobe part of one of the
thicker ends. Multiple resonance modes are
visible. Calculated mode positions are indicated by
red triangles. Inset: the fundamental modes have
a fine splitting with Q factors up to 7.7 × 10 3.
The combination of titania with rolled-up nanotechnology presents many interesting
opportunities for novel applications. Control over the structural and optical properties
of rolled-up titania microtubes has been achieved by means of a proper tuning of the fabrication parameters. Optical characterization using tools such as polarization-resolved
near-field maps of optical modes allow us to probe rolled-up resonators, providing
feedback for fabrication improvements, leading to application.
Acknowledgements: We thank B. Eichler, R. Engelhard and S. Baunack for the technical
support, also D. Grimm, B. Martin and S. Harazim for assistance in clean room maintenance. Collaborations with R. Hühne and C. Ortix are important to our ongoing and
future projects.
[1]
[2]
[3]
[4]
[5]
[6]
J. Zhang et al., Nano Lett., 15 (2015), 422.
Y. Huo et al., Nature Phys. 10 (2013) 46.
A. Madani et al., Opt. Lett. 2013, 39 (2), 189-192.
S. Giudicatti et al., J. Mater. Chem. C 2014, 2 (29), 5892-5901.
S. Böttner et al., App. Phys. Lett. 2014, 105 (12), 121106.
J. Trommer et al., Opt. Lett. 2014, 39 (21), 6335-6338.
Cooperation: Johannes Kepler University Linz, Austria
Funding: BMBF project QuaHL-Rep, EU project HANAS, China Scholarship Council
Research Topic 3.4
Functional molecular nanostructures and interfaces
Authors: Y. Zhang, A. Svitova, C. Schlesier, K. Junghans, Q. Deng, N. Samoylova, A. A. Popov
People involved: A. Beger, A. Brandenburg, Q. Deng, E. Dmitrieva, D. Krylov, M. Rosenkranz,
S. Schiemenz, C. Schlesier, F. Ziegs
Responsible Directors: B. Büchner, O. G. Schmidt, J. Eckert
Summary: Recent studies of endohedral metallofullerene synthesis and electron transfer properties in IFW are reviewed. The first endohedral fullerene structure LaSc 2N@C 80
with heptagon is synthesized and characterized. High thermodynamic stability and low
yield of LaSc2N@C 80 -C s (hept) show that fullerene formation is not fully controlled by
thermodynamic factors. New type of clusterfullerenes with two lanthanide ions, central carbon atom and Ti = C double bond (e.g. Lu2TiC@C 80) is discovered and conditions
for a highly selective synthesis of such species are revealed. A plethora of endohedral
metallofullerenes with cluster-based redox activity and the mechanism of their redox
reactions is described.
Endohedral metallofullerenes:
new cages, clusters, and electron transfer phenomena
Endohedral metallofullerenes (EMFs) are hollow-shaped carbon cages encapsulating
metal ions or cluster in their inner space [1]. By virtue of such hybrid structure,
chemical and physical properties of EMFs are determined by (i) the fullerene cages, (ii)
endohedral species, and (iii) by the phenomena resulting from the mutual interactions
of the carbon cage and encapsulated cluster. All these aspects should be therefore
carefully explored.
Various carbon cages have different π-system topology, which in due turn varies the
frontier molecular orbital energies and their spatial distribution. Besides, geometrical
properties of the σ-carcass (e.g. its size and shape) have crucial influence on their ability to form endohedral fullerenes [2]. Hence, the study of the possible fullerene cages
and their role in EMF formation is an important aspect of the EMF research. According
to the IUPAC definition, fullerenes are “Compounds composed solely of an even number
of carbon atoms, which form a cage-like fused-ring polycyclic system with twelve fivemembered rings and the rest six-membered rings”. The heptagon-containing fullerenes
have been studied theoretically and were found less stable than conventional
pentagon/hexagon cages, and hence their formation in a standard arc-discharge
synthesis has never been observed. The synthesis of nitride clusterfullerenes usually
yields two isomers with the C 80 cage that dominate in the M3N@C2n fullerene mixture [1].
The most abundant isomer has Ih cage symmetry, whereas the second most abundant
structure is the isomer with the D5h cage. However, our recent study of the mixedmetal La-Sc system revealed formation of the third isomer of LaSc2N@C 80, whose structure was elucidated by single-crystal X-ray diffraction [3]. The new EMF structure has 13
pentagon and is the first example of an EMF molecule with a heptagonal ring (Fig. 1).
Computational DFT study shows that LaSc2N@C 80 with heptagonal ring is almost as
stable as the Ih cage isomer, which refute the claims on the low stability of heptagoncontaining fullerenes. If the isomeric distribution would be governed by the thermodynamic stability, a much higher yield of the heptagon-containing isomer might be
expected. However, experimental studies contradict this expectation. The reason for the
low yield of heptagonal fullerenes may be in the kinetic factors, i.e. the ease of the
structural rearrangement to other fullerene cages. Comparison of the C 80 -Cs (hept) and
the most abundant C 80 -Ih cage isomers reveals their close similarity. These two structures
are related by a single Stone-Wales transformation, i.e. a “rotation” of the C2 fragment
highlighted in light green in Fig.1 by 90° and corresponding readjustment of the σ-cage
network. The barrier towards such rearrangement of ca 6.5 eV is rather high for a room
temperature but can be easily accessible in the hot carbon arc during the fullerene
formation.
The mutual stabilization of the cage and endohedral species is well understood based on
the metal-to-cage electron transfer, but prediction of the structures of possible endohedral cluster remains a challenging problem. A plethora of metal or hybrid metal/nonmetal clusters has been already encapsulated within the carbon cage, and new examples
of species capable of forming the EMFs molecules are continuously reported. Choosing
the type of clusterfullerene to be formed and a metal or a combination of metals to be
encapsulated the electronic and magnetic properties of EMFs can be varied in a broad
range. Hence, exploration of the species which can be encapsulated into the carbon cage
during the EMF formation is another important aspect of the EMF research, where
serendipity plays an important role. In an attempt to synthesize of the mixed-metal
Ti-Lu nitride clusterfullerenes by the arc-discharge with NH3 reactive gas atmosphere our
group recently discovered formation of the new type of clusterfullerenes, in which the
central atom is carbon making a double bond to a titanium atom and single bonds to two
lanthanide ions (Fig. 2) [4]. In fact, the structure of Lu2TiC@C80 is very similar to that
of Lu2ScN@C80, to which it is isoelectronic. Further exploration of reaction conditions
revealed that Ti-carbide clusterfullerenes can be obtained with high selectivity by
introducing methane CH4 into the arc-discharge generator.
Fig. 1: Molecular structures of LaSc 2N@C 80 isomers
with C 80 - Cs (hept) (top) and C 80 -Ih (bottom) cage
isomers (Sc atoms are magenta, La is orange, and
N is blue). The cage fragment near the heptagon is
highlighted in red, the C-C bond which is “rotated”
in the Stone-Wales rearrangement is highlighted in
light green.
Fig. 2: Molecular structure of Lu 2TiC@C 80
determined by single crystal X-ray diffraction
and schematic description of endohedral
clusters in Lu2TiC@C 80 and Lu2ScN@C 80.
Irrespective of the endohedral cluster composition, all EMFs have one common element
– the metal/π-system interface. Behaviour of this interface under electron transfer conditions has been thoroughly studied by electrochemistry and spectroelectrochemistry.
While the carbon cage is the only redox-active center in empty fullerene, in EMFs both
the fullerene cage and the endohedral species can be redox active. Of particular interest are EMFs exhibiting endohedral redox activity. In such processes, the fullerene cage
merely acts as an inert container, transparent to electrons and stabilizing the variable
spin and charge state of endohedral species [5]. Lu 2TiC@C 80 is an illustrative example
of such EMF: its LUMO is to a large extent localized on Ti ion, and reduction of Lu2TiC@C 80
proceeds via the change of the Ti valence state. On the contrary, reduction of isostructural and isoelectronic Lu2ScN@C 80 is a cage-based process and is shifted to a more
negative potential range by 0.51 V [4].
Unique redox behaviour of endohedral CeIII ion is found in cerium-based nitride clusterfullerenes such as CeM2N@C 80 (M = Sc, Y, Lu) [6]. Due to the large ionic radius of CeIII
(1.01 Å), encapsulation of Ce-based nitride clusters within medium-size carbon cages
results in the significant inner strain. Oxidation of CeIII via removal of the 4f electron
forms CeIV with much smaller ionic radius (0.87 Å), and therefore strained Ce-based EMFs
are prone to oxidation as a way to release the strain. The Ce-based oxidation of such EMFs
can be proved by NMR spectroscopy as exemplified in Fig. 3 for CeSc2N@C 80 : formation
of the diamagnetic [CeIVSc2N@C 80] + cation results in the shift of 13C and 45Sc NMR
resonance lines in comparison to the paramagnetic CeIII Sc2N@C 80. Variation of the
CeM2N cluster by choosing the metal M of different size (Sc, Lu, Y) modifies the inner
strain and therefore changes oxidation potential of the endohedral CeIV/CeIII pair. On
the other hand, variation of the carbon cage also results in the changes of the inner
strain. A systematic study of Ce x M3−x N@C 2n with different cage size (2n = 78 – 88)
showed that the oxidation mechanism of these molecules is governed by a subtle balance
between the cluster and the cage size [7].
Fig. 3: Top: 13C and 45Sc NMR spectra of
CeSc 2N@C 80 and [CeSc 2N@C 80 ] +.
Bottom: change of the cluster shape in
CeY2N@C 80 from highly strained pyramidal
to planar induced by oxidation.
Sc 3N@C 80 is an example of endohedral redox activity with Sc 3N-based reduction.
Chemical derivatization such as cycloaddition changes the π-system of the fullerene and
hence can substantially affect the electrochemical properties of Sc3N@C 80. Sc3N@C 80
has two types of CC bonds located at pentagon/hexagon [5,6]) and hexagon/hexagon
[6,6] edges. The anion radicals of isomeric [5,6] and [6,6] Sc3N@C 80 benzoadducts were
studied by electron spin resonance spectroscopy [8]. In both compounds the rotation of
the Sc3N cluster is frozen and the spin density distribution of the cluster is highly
anisotropic, with hyperfine coupling constants of 9.1 and 2 × 33.3 G for the [5,6] adduct
and ∼ 0.6 and 2 × 47.9 G for the [6,6] adduct. Remarkably, the subtle variation of the
exohedral group position on the surface of the cage results in very pronounced changes
of the spin density distribution and on the dynamics of the encapsulated Sc3N cluster.
Fig. 4: Molecular structures, spin density distribution, and ESR spectra of anion radicals
of isomeric [5,6] and [6,6] Sc 3N@C 80 benzoadducts.
[1]
[2]
[3]
[4]
[5]
A. A. Popov, et al., Chem. Rev. 2013, 113, 5989.
Q. Deng and A. A. Popov, J. Am. Chem. Soc. 2014, 136, 4257.
Y. Zhang et al., Angew. Chem.-Int. Edit. Engl. 2014, DOI: 10.1002/anie.201409094.
A. L. Svitova et al., Nat. Commun. 2014, 5, 3568, DOI: 3510.1038/ncomms4568.
(a) Y. Zhang and A. A. Popov, Organometallics 2014, 33, 4537;
(b) A. A. Popov and L. Dunsch, J. Phys. Chem. Lett. 2011, 2, 786.
[6] Y. Zhang et al., J. Phys. Chem. Lett. 2013, 4, 2404.
[7] Y. Zhang et al., Nanoscale 2014, 6, 1038.
[8] A. A. Popov et al., J. Am. Chem. Soc. 2014, 136, 13436.
Funding: DFG
Cooperation: Univ. of Texas at El Paso (USA); Univ. of California, Davis (USA);
Purdue University at Fort Wayne (USA).
Research Area 4 TOWARDS PRODUCTS 67
Research topic 4.1
Surface acoustic waves: Concepts, materials & applications
People: S. Biryukov, E. Brachmann, R. Brünig, A. Darinskii 2, T. Gemming, V. Hoffmann, F. Kiebert,
E. Lattner, G. Martin, S. Menzel, G. K. Rane, H. Schmidt, M. Seifert, E. Smirnova1, A. Sotnikov,
M. Spindler, H. Turnow, U. Vogel, A. Vornberger, S. Wege, M. Weihnacht, A. Winkler
Responsible Directors: B. Büchner, J. Eckert, O. G. Schmidt
Summary: The center “SAWLab Saxony ” was established bringing together IFW’s competence in acoustoelectronics with those of other Saxon research groups and high-tech
companies active in this field. In 2014 the research emphasis was mainly put on the
thorough investigation of high temperature durable piezoelectric substrates and appropriate electrode metallization systems for SAW devices as well as on systems with
acoustofluidic interaction. Hereby, different new piezoelectric materials were characterized regarding their acoustic behavior and a complete parameter set was established
for CTGS crystals as currently the most promising member of langasite family for high
temperature applications. As for advanced thin film electrodes systems made of
refractor y elements, AlRu alloys and metallic glasses were investigated. Moreover
dedicated analysis methods were developed for surface- and interface studies on
SAW-based film systems.
In the research topic 4.1 the „SAWLab Saxony - Competence Center for Acoustoelectronic
Fundamentals, Technologies and Devices” (www.SAWLab-saxony.de) was founded, joining all microacoustic activities of the IFW Dresden and combining this expertise with
competences and skills of cooperating Saxon research institutes, universities and hightech companies. This interdisciplinary research includes acoustoelectronic fundamentals and novel materials as well as advanced applications with exploitation by innovation-oriented small and medium-sized enterprises. In this frame, IFW activities will
continue to focus on emerging and future-oriented fields of SAW components, like
high-grade frequency filters and resonators as well as sensors and actuators with enhanced capabilities. Here, materials aspects are crucial regarding piezoelectric substrates
and thin film electrodes with increased temperature and power capabilities necessary for
68 Research Area 4 TOWARDS PRODUCTS
SAW structures with enhanced precision and lifetime. Besides fundamental investigations
regarding general effects of wave propagation [1], dynamic behavior of polar dielectrics
[2] and acoustofluidic interaction phenomena, the research was also focused on
dedicated materials for high-temperature applications such as i) advanced piezoelectric
substrate materials, ii) new routes for thin film electrode materials with high thermal
stability and iii) dedicated surface and interface study.
i) Advanced piezoelectric substrate materials
Besides commercially well-established high frequency filters, resonators and actuators,
SAW devices presently capture new fields of application namely as passive SAW-based
sensors and ID tags. Due to inherent robustness and the capability for wireless interrogation such devices become ready for an emerging field of industrial and consumer
applications. Nevertheless, a remaining challenge is still the required durability against
extreme temperatures, particularly in oxidizing atmosphere. Here, new piezoelectric
crystals were characterized with high precision regarding their acoustical material
parameters, among them different members of langasite and oxoborate families. A serious alternative for high temperature SAW devices is CTGS (Ca3TaGa3Si2O14) belonging
to the same crystal family like the commonly used LGS (langasite, La3Ga5SiO14) but showing a more ordered and thus more stable crystal structure. By combining different
techniques based on SAW and BAW (Pulse-Echo, Resonance-Antiresonance, LAwave) with
dielectric measurements a strongly improved complete set of acoustic material data was
determined for room temperature, overcoming the inaccuracies of formerly known
data sets.
ii) Thin film electrode material systems with high thermal stability
High-temperature stable electrode systems based on magnetron sputtered refractory metals like tungsten and molybdenum single and multilayers as well as intermetallic Al(Ru)
thin films were investigated on LGS and CTGS substrates. The choice of these material systems is based on their high melting point (> 2000 °C) and thus a minimal creep related
damage as well as a compiant coefficient of thermal expansion (CTE) of the materials
in contact to the substrates. Additional features are a relatively high thermal conductivity and low electrical resistivity (< 15 μΩcm for 100 nm thin films) which is stable over
many temperature cycles. In-depth material characterization was performed to understand and tailor the microstructure using different techniques such as X-ray diffraction
and reflectivity measurements, scanning and transmission electron microscopy, Auger
electron spectroscopy, atomic force microscopy etc.
Since even at high temperatures a chemical reaction with the substrate was not observed
for W/Mo a diffusion barrier to the CTGS substrate is not necessary. A high thermal
stability up to 800 °C of all the W/Mo films on CTGS was also observed under vacuum
(Figs.1,2). The RuAl alloy thin films (thickness 110 nm) have also been heated up to
Fig. 1: Focused ion beam cuts of W/Mo
multilayers on CTGS after annealing at 800°C
for 12h (a - d: increasing number of layers).
Fig. 2: Electrical resistivity of different W/Mo
thin films on CTGS upon annealing.
800°C. For this material system the phase formation, surface morphology, electrical conductivity and film architecture have been investigated. The results show that the RuAl
phase is formed very well on reference Si/SiO2 substrates but oxidation of the Al atoms
takes place due to diffusion of O out of LGS and CTGS substrates. This oxidation effect
destroys the RuAl phase completely at 800°C on LGS substrates (Fig. 3). This behavior
is less pronounced on CTGS. However, the results on Si/SiO2 reference substrates prove
that the RuAl alloy is also a promising metallization candidate for SAW devices, but one
needs to overcome the challenges on LGS and CTGS by appropriate barrier layers to
inhibit the diffusion of O and to protect the film against oxidation. In conclusion, the
W-Mo and Al-Ru materials systems are suitable metallization candidates for high
temperature SAW devices, being an alternative to the commercially used Pt thin films
electrodes [3].
Thin film metallic glasses are characterized by a high yield strength and a low diffusivity at moderate resistivity compared to crystalline thin films of the same dimensions. Due
to the lack of microstructural defects such as grain boundaries (Fig. 4), internal diffusion and degradation effects are drastically reduced. The research has been focused on
Fig. 3: RuAl film composition on LGS after
annealing at 800 °C for 10 h under high
vacuum condition. Inset: FIB image illustrating
film architecture.
Fig. 4: FIB cross sections of a crystalline Ni
and an amorphous NiZr thin film.
fundamental investigations especially on the binary Ni-Zr as well as Cu-Ti material
systems for SAW device applications. For this purpose the alloys were deposited by
simultaneous co-sputtering whereas for multilayers the two material components were
deposited successively. On both material systems the surface roughness, intrinsic
mechanical stress, electrical resistivity, crystal phase formation as well as the Young’s
modulus were studied in dependence on composition. It was observed that microstructure and phases have a strong influence on the measured properties. In particular an
extremely low surface roughness in the nm range and electrical resistivity below
200 μΩcm are results observed for the amorphous thin films [4].
The interface between the metallization layer and the piezoelectric substrate is crucial
regarding the texture of the layers and their microstructure evolution, and thus
influences performance and lifetime of SAW devices especially under high acoustic
load. Studies on LiNbO3 and LiTaO3 with several metallization layers (Ta, Ti, TaNx , TiNx )
emphasize the role of cleaning pre-treatment of the substrate surface on layer per formance. Conventional preparation like low energy ion etching or thermal treatment
may alter the chemical state of the surface. Based on analytical results using a dedicated Angle-Resolved X-Ray Photoelectron Spectroscopy (ARXPS) algorithm an
rf-plasma treatment process was developed that results in an ideal cleaned surface. This
ARXPS algorithm allows a complex interface modelling with robust mathematical
approach that can lead to further understanding of the interface effects [5].
[1]
[2]
[3]
[4]
[5]
A.N. Darinskii et al., Ultrasonics, 54, 1999–2005 (2014).
E. Smirnova et al., J. Appl. Phys. 15, 054101 (2014).
G.K. Rane et al., Thin Solid Films 571 (2014), 1-8.
H. Turnow et al., Thin Solid Films, 561C, 48-52 (2014)
U. Vogel et al., Surface and Interface Analysis 46 (2014), 1033-1038
Funding: BMBF InnoProfile-Transfer (03IPT610A MiMi, 03IPT610Y HoBelAB),
DFG, Vectron International, Creavac, SAW Components Dresden
Cooperations: TU Bergakademie Freiberg; TU Dresden; 1 Ioffe Physical Technical Institute RAS, St. Petersburg, Russia; 2 Institute for Crystallography RAS, Moscow, Russia;
InnoXacs; Vectron International; Creavac, SAW Components Dresden
Research Topic 4.2
Materials for biomedical applications
Authors: A. Gebert, A. Helth, P. Flaviu Gostin, M. Bönisch, K. Zhuravleva, S. Abdi, S. Pilz, R. Schmidt, S. Oswald,
H. Wendrock, A. Voß, M. Uhlemann, U. Wolff, D. Pohl, B. Rellinghaus, T. Gemming, M. Calin, U. Hempel1, R. Medda2,
E. A. Cavalcanti-Adam2, C. Lekka3
People involved: H. Attar, H. Bußkamp, S. Donath, D. Eigel, M. Frey, M. Guix, S. Hampel, L. Helbig, K. Hennig, V. Hoffmann,
J. Hufenbach, M. Johne, S. Kaschube, A. Kippenhahn, T. Kirsten, B. Koch, G. Kreutzer, U. Kühn, V. Magdanz, S. Makharza,
M. Medina, A. K. Meyer, S. Pauly, A. Schubert, L. Schwarz, F. Senftleben, A. Teresiak, K. Wruck
Responsible Directors: B. Büchner, O. G. Schmidt, J. Eckert
Summary: Advances in biomedical applications require novel material-based solutions
under exploitation of their unique properties. The combination of different material
classes yields biofunctionalities at greater dimension in analytics, diagnostics and
therapeutics. A profound knowledge-base on the interaction of the material with the
biological system has to be developed to tailor materials properties and to control the
bio-solid-interface. At the IFW a unique expertise on different material classes for
novel biomedical applications is concentrated ranging from nanomaterials (carbon
nanostructures, rolled-up materials) over bio-microfluidics and microacoustics based
on thin films up to bulk materials. A special research focus are new Ti-based alloys for
hard tissue regeneration and replacement with most suitable mechanical performance
and excellent biocompatibility. A key aspect is the design of bioactive surface states
for optimum bone–metal interactions towards reliable osseointegration also in case
of age-induced bone diseases. Successful examples of nanoscale surface modifications
of a new generation of Ti-based implant alloys are demonstrated in the following.
Nanoscale surface modification of Ti-based alloys for hard tissue implants
A world-wide growing population of elder people and the related rising problem of ageinduced bone diseases like osteoporosis tighten the demands on materials properties
used for human orthopaedic implants towards better mechanical and biological compatibility and longevity. For hard tissue regeneration, Ti and its alloys are the most favoured
implant materials, but there are still serious problems to be solved. A major issue is the
bone-implant stiffness mismatch causing stress-shielding effects with consequence of
bone resorption and implant loosening. Multiple cases of implant failure due to limited
materials strength are observed. The release of toxic metallic species by corrosion and
wear is problematic due to inflammatory cascades. Suitable surface states must be
created which enable better osseointegration. Therefore, careful material design is
necessary to attain optimum biofunctionalities [1].
We develop new non-toxic Ti-based materials with suitable balance of low stiffness and
high static and dynamic strength as well as high durability under physiological conditions. This comprises alloy design with particular microstructural features at different
length-scales ranging from microcrystalline via nanocrystalline to amorphous states. In
the focus are alloys of the metastable Ti-Nb system. For beta-type Ti-(40-45)Nb, compositional modifications with beta stabilizers like indium or grain refiners like boron and
variations of casting and thermo-mechanical processing conditions are studied to
suitably tailor microstructure-property relations [2]. Porous alloy structures with very
low elastic modulus are produced via powder metallurgical approaches and are intended to be used as mechanically stable substrates and carrier of bioresorbable materials
or drug delivery systems in bone defects [3]. Special emphasis is given to alloys that
mechanically stimulate bone healing processes based on a combination of superelastic
and shape memory effects like martensitic Ti-(13-30)Nb [4]. Amorphous Ni- and Cu-free
Ti-based alloys are a particular class of materials that are developed towards an optimum
balance between maximum glass-forming ability and outstanding mechanical performance and corrosion resistance [5,6].
A decisive prerequisite for long-term implant application of those novel Ti-based alloys
is the generation of bioactive surface states for optimum osseointegration. That
comprises the control of the complex processes at the bio-solid interface towards the
stimulation of the activity of bone forming cells (osteoclasts) against that of bone resorbing cells which is the basis for bone tissue regeneration. The implant surface state
with its topography and roughness, composition and surface energy controls these
interactions. Many established surface treatments for commercial Ti-based implant
materials yield distinct micrometer-sized features. But recent studies revealed that
nanometer-sized modifications better scale with cell functions. Therefore, strategies
for the generation of suitable nanoscale surface modifications of the new generation of
Ti-based implant materials are to be developed. Selected successful examples for betatype Ti-Nb alloys are discussed in the following.
The high Nb content of Ti-(40-45)Nb alloys yields an extremely high corrosion resistance
and therefore, established acid etching procedures for metallic implant materials are
not sufficient for effective surface modification. In a new approach the applicability of
a H2SO4 /H2O2 treatment for chemical nanoroughening of the alloy surface was demonstrated [7,8]. The nanotopography comprises a network of nearly semi-spherical pits of
25 nm mean diameter (Fig. 1). While the native passive layer on a mechanically ground
alloy surface is very thin and has a mixed state of various Ti and Nb-oxides, the chemical treatment enhances the passive layer growth. A strong enrichment of Nb2O5 relative
to TiO2 in the surface layer was detected. The use of analytical methods such as X-ray
photoelectron spectroscopy (XPS) (Fig. 2) and Auger electron spectroscopy (AES) is
Fig. 1: SEM micrograph of a Ti-40Nb
surface after chemical nanoroughening
Fig. 2: XPS spectra of the Ti 2p state taken
from a Ti-40Nb surface, polished (black)
and nanoroughened (brown); different oxide
states are deconvoluted
crucial for the characterization of the materials chemical surface states. But it is challenging due to limited lateral resolution, chemical effects on peak shifts and shapes and
the destructive nature of depth-profiling with ion sputtering. Tailored approaches were
implemented to allow the calculation of (semi-)quantitative element concentrations
from depth profiles [9]. In vitro analyses were conducted at the TU Dresden (AG Hempel)
and clearly indicated that chemically nanoroughened Ti-Nb surfaces increase the
metabolic activity and osteogenic differentiation of human mesenchymal stromal
cells (hMSC) (Fig. 3). Those effects are significantly more pronounced for the alloy than
for cp-Ti.
Fig. 3: Fluorescence micrograph of hMSC
on a nanoroughened Ti-40Nb surface
(@ U. Hempel, TU Dresden)
When an implant surface is in contact with a physiological environment, one of the first
processes is the formation of an extracellular matrix as basis for bone cell adhesion,
spreading and differentiation finally leading to bone tissue growth. A recently emerged
idea is to stimulate those cell reactions by mimicking an extracellular environment
with synthetic means. This comprises the creation of well-defined ordered nanotopographies on bulk solid surfaces in terms of nanoparticle patterns and their functionalization with bioactive molecules. Our collaboration partner at Univ. Heidelberg (AG E.A.
Cavalcanti-Adam) developed an approach that starts with nanolithography based on dip
coating of Au-loaded diblock copolymer micelles for monolayer formation on a solid
substrate and subsequent oxygen plasma treatment for removal of the organic residues.
In our joint study we could demonstrate that by this way highly ordered hexagonal
patterns of Au nanoparticles with 5 -7 nm diameter and interparticle distances ranging
from 70 to 100 nm (depending on the polymer-type used) can be created on fine-polished
beta-type Ti-40Nb surfaces. The near-surface regions were characterized with TEM, this
way the detailed nature of the fcc Au nanoparticles was analysed and an amorphous
passive layer of (Ti,Nb)-oxides which was formed during the plasma treatment was
detected (Fig. 4). Samples with those surface states were coated with polyethylene
glycol and the Au nanoparticles were functionalized with cyclic thiol-peptide ligands. In
vitro tests revealed significant effects on the early response of hMSC towards an improved
regulation of local cell adhesion and a reduction of the population heterogeneity. Those
biofunctionalized nanopatterned alloy surfaces appear to be very promising tools for
selecting hMSC with homogeneous phenotype [10].
Fig. 4: TEM image surveying the near-surface
regions of Ti-40Nb with passive layer and
arrangement of Au nanoparticles
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
M. Calin et al., Mater. Sci. Eng. C 33 (2013) 875
M. Calin et al., J. Mechan. Beh. Biomed. Mater. 39 (2014) 162
K. Zhuravleva et al., Mater. Design 64 (2014) 1
M. Bönisch et al., J. Appl. Cryst. 47 (2014) 1274
S. Abdi et al., Intermetallics 46 (2014) 156
S. Abdi et al., J. Biomed. Mater Res. Part B (in press)
P.F. Gostin et al. J. Biomed. Mater. Res. Part B 101 (2013) 269
A. Helth et al., J. Biomed. Mater. Res. Part B 102 (2014) 31
S. Oswald et al., Surf. Interface Anal. 46 (2014) 683
R. Medda et al., Interface Focus 4 (2014) 20130046 Funding: DFG SFB Transregio 79, EU ( BioTiNet and ITN VitriMetTech),
DAAD-IKYDA (Greece)
Cooperations: 1 TU Dresden, 2Ruprecht-Karl-Universität Heidelberg,
3
Universitity of Ioannina, Greece
Research topic 4.3
High strength materials
Leibniz Application Laboratory Amorphous Metals
Authors: U. Kühn, J. Freudenberger, A. Gebert, J. Hufenbach, P.F. Gostin, S. Horn, M. Uhlemann,
S. Scudino, A. Leonhardt, F. Silze, J. Sander
People involved: B. Bartusch, S. Bickel, R. Buckan, H. Bußkamp, S. Donath, M. Frey, D. Geissler,
K. Hennig, M. Johne, R. Keller, E. Knauer, H. Merker, C. Mix, S. Neumann, S. Pauly, K.-G. Prashanth,
H. Schwab, D. Seifert, A. Sobolkina, M. Stoica, H. Wendrock, A. Voidel, A. Voß, T. Wolf, J. Zeisig
Responsible Directors: J. Eckert, L. Schultz
Summary: The increasing demand of industry for equipment (tools, devices, machine
parts, accessories etc.) with excellent durability under extreme loading conditions
promotes the development of innovative materials possessing e.g. high strength,
hardness, wear resistance, ductility and corrosion resistance. Novel manufacturing
technologies, such as special casting methods, which ensure accelerated solidification,
selective laser melting and thermoplastic forming present a fast and energy efficient
option for load-adapted adjusting of mechanical properties. Materials under investigations are metallic glasses, glass-matrix composites, crystalline materials with
extraordinar y mechanical properties, as e.g. high strength steels, high strength lightweight alloys, highly strengthened conductors, and cement-based materials reinforced with carbon nanotubes. The basic idea is to transfer sophisticated technologies
combined with specific newly developed materials towards industry.
High performance steel alloys
This topic contains a multiplicity of activities and projects, respective (1) high strength
and/or corrosion resistant tool steels, (2) parts of high strength steels produced by
selective laser melting (SLM) and (3) filler material (steel wire) in overlay welding
processes. By applying a tailored casting, SLM or welding process and sufficiently high
cooling rates excellent mechanical properties (compression strength of up to 5.5 GPa
combined with a plastic strain of 20%) can be obtained for the steel alloys already in
as-prepared state [1]. This opened the possibility for reducing multi-stage, time-consuming and cost-intensive manufacturing processes and led to several patents [2-6].
Since no subsequent heat-treatment is required, the cooling parameters applied during
the casting process play a key role with respect to the evolving microstructure and
resulting properties. Therefore, detailed investigations of the phase formation, especially the crystal structure and morphology of numerous types of carbides were performed
(Fig. 1a, b) [7] and accompanied by thermodynamic modelling work. This resulted in a
profound understanding of possible ways for tuning the microstructure and properties
of these alloys to certain application purposes, e.g. for cutting/punching/mining tools
(Fig. 2a- c) with excellent service life as well as filler material (wire) for deposition
welding [6]. Furthermore, reinforcing lattice structures were prepared by SLM for
various applications (Fig. 3).
Fig. 2: (a) Knives for medical filter production; (b) bucket tooth;
(c) pick head for mining machine.
High strength metallic materials prepared by SLM
It could be demonstrated for the first time that bulk metallic glasses are producible by
selective laser melting. The method opens a possibility to overcome intrinsic limitations
regarding the complexity and dimensions of the obtainable geometries compared to the
commonly known casting process. For the first successful experiments an iron-based
metallic glass was used, but this approach is viable for a variety of metallic alloys [8].
Furthermore, there is a strong demand from aerospace industry for the development of high strength and lightweight materials with enhanced properties. The SLM
process enables the manufacturing of precise and homogenous multicomponent Ti- and
Al-based alloys nearly without limits in design and ensures the research on sophisticated alloys with very different physical and chemical characteristics [9,10].
Fig. 1: (a) Optical micrograph of the dendritic
structure of the as-cast Fe 84.3Cr4.3 Mo 4.6V2.2 C 4.6 alloy
showing the distribution of the present phases;
(b) SEM image of the deep etched
Fe 84.3Cr4.3 Mo4.6V2.2C 4.6 alloy illustrating the fine
network-like structure formed by complex carbides
and its arrangement within the material.
Thermoplastic forming of bulk metallic glasses
The unique crystallisation behaviour of metallic glasses enables a thermoplastic forming process in the supercooled liquid region (SCLR), because of the significant softening of the BMGs above Tg. These special characteristics lead to processing temperatures
and pressures that are similar to those of plastics. The main advantage is the decoupling
of the rapid cooling, required to form the amorphous structure, from the shaping
process. In close collaboration with the research technology division of IFW a device has
been developed that allows producing semi-finished products of refractory metal-based
glassy granulates in protective atmosphere. First parts using such Zr-based glass granulate have been prepared by shaping the glass above the glass transition temperature
just in order to demonstrate the feasibility of the technology.
Stress and fatigue corrosion of bulk metallic glasses
Stress corrosion cracking investigations are carried out on the bulk glassy
Zr52.5 Cu17.9 Al 10 Ni14.6Ti 5 alloy (Vit 105) by means of three-point bending at constant
deformation in chloride-containing electrolytes with an in-house designed setup. A
special three-electrode electrochemical cell is placed around the test sample and enables in situ polarisation control and measurement. Potentiostatic experiments during
static mechanical loading are performed at several anodic potentials and chloride
Fig. 3: Lattice structure produced by SLM technology.
concentrations selected based on anodic polarisation experiments [11]. Typically,
under static loading, after a certain incubation time, the current starts to increase
suggesting the initiation of localized corrosion. At a later point, the stress also starts to
decrease gradually indicating stress corrosion cracking with stable crack propagation.
At the end, unstable crack propagation is observed, which is due to overload of the
remaining load-bearing section. Microscopic analysis of fracture surface revealed a
clear distinction between the two modes of crack propagation. Stress corrosion cracking is perpendicular to the major tensile stress component. This is accompanied by crack
branching and very limited shear banding (Fig. 4).
Fig. 4: SEM image showing the fracture surface of a
bulk glassy Zr 52.5 Cu 17.9 Al 10 Ni 14.6Ti 5 alloy (Vit 105)
sample after a stress corrosion cracking experiment.
Functionalized carbon nanotubes in cement-based composites
The use of the reinforcing effect of carbon nanotubes on the tensile strength of cementbased composites requires a strong CNT-matrix interaction which would promote load
transfer across the interface. In order to understand and predict the phenomena taking
place at the CNT-matrix interface, various types of carbon nanotubes prepared using
acetonitrile, cyclohexane, and methane as the carbon source were examined with regard
to their surface properties. Working in close collaboration with Leibniz Institute of
Polymer Research, significant differences were revealed in the acid-base features,
surface tension as well as in the wetting behavior of the prepared CNTs. For example, the
hydrophobicity of the CNTs decreases by utilizing the carbon sources in the following
order: cyclohexane, methane, and finally acetonitrile. The sol-gel coating of the CNTs
with silica showed strong dependence on the chemical composition of the nanotube
surface [13]. This basic research is a prerequisite for the specific application of CNTs in
inorganic cementitious materials.
High-strength Cu-based conductor materials
The microstructure of single phase copper alloys is altered by cold deformation. Depending on the processing parameters like temperature and intrinsic material parameters as
stacking fault energy, the dominant deformation mechanism is different and the refinement of the microstructure bears other rates with respect to the deformation strain. The
formation of deformation twins is activated at low homologous temperature or at low
stacking fault energy. Both also lead to smaller grain sizes achieved at a certain
deformation strain. Lowering the temperature only yields to a high efficiency in strain
hardening with respect to room temperature deformation for intermediate stacking fault
energies. The maximum efficiency occurs in the vicinity of the onset of deformation
twinning at room temperature which was found for a stacking fault energy of 30 mJ/m2.
In this condition cryo-deformed CuAl3 alloys show a strength of 890 MPa, which represents an enhancement of 180 MPa when compared to room temperature deformation
[14]. Further research will foster this conception of activating mechanical twins by
cryo-deformation also in CuAg alloys which so far showed the optimum combination of
high strength and high electrical conductivity.
Brazing material corresponding to particular industrial requirements
Fig. 5: EDX-Mapping for the wetting of Cu-Ga braze
filler on 304L steel in cross section. The dashed line
indicates the interface.
Many components used in structural and functional applications are permanently joined
by brazing. Therefore, a multitude of different and complex braze fillers are on the
market to fulfill the specific requirements defined by each combination of materials. The
melting range of the braze filler has to match the target temperature and the processability of the alloy has to be adequate in order to ensure large-scale production. In addition, next to a sufficient wettability also the interactions and reactions at the solidliquid interface are crucial for understanding and improving the brazing process. In
cooperation with Umicore AG & Co. KG a substitute alloy for the industrial standard
braze filler AgCu28 has been successfully developed and systematically investigated
(Fig. 5).
Due to an extensive alloy development combining materials science and industrial
demands a composition based on the ternary system Cu-Ag-Ga has been characterized
and patented. The new braze filler contains 40 % less Ag. The effect of the additional
element Ga on the wettability on stainless steel surfaces was investigated on the macroscopic scale (contact angle measurements) as well as on the microscopic scale (SEM,
TEM), so that a detailed understanding of the complex brazing process was achieved.
Electrochemical micromachining of metallic glasses
Owing to their outstanding properties bulk metallic glasses are very promising materials for the production of microparts. But shaping them without heat input is still a
challenge. An alternative microprocessing method, which operates at room temperature,
is the pulsed electrochemical micromachining (ECMM). Employing ultra-short voltage
pulses between a micro-sized tool electrode and the BMG surface induces a highly localized material removal process. The applicability was firstly proven for Zr- and Fe-based
BMGs using non-aqueous electrolytes. But due to its immanent risks the employment of
methanolic solutions is not favorable. However, using aqueous solutions Fe-based BMGs
form stable passive layers, which disturb the machining. These effects can be minimized
by adding an oxidizing agent Fe 2(SO4)3 [12]. To demonstrate the high potential of the
ECMM optimum hole and line structures were machined (Fig. 6).
[1] J. Hufenbach et al. J. Mater. Sci. 47 (2012) 267
[2] U. Kühn et al. Patent 10608 DE 10 2006 024 358
[3] J. Hufenbach et al. Patent 11017 DE 10 2010 062 011 +
11017 PCT WO2012069329 (pending)
[4] U. Kühn et al. Patent 11009 DE 10 2010 041 366.6 +
11009 PCT/EP2011/066283 (pending)
[5] J. Zeisig et al. (patent application deposited)
[6] J. Hufenbach et al. (patent application deposited)
[7] J. Hufenbach et al. Mater. Sci. Eng. A 586 (2013) 267
[8] S. Pauly et al. Mater. Today 16 (2013) 37
[9] K. G. Prashanth et al. Mater. Sci. Eng. A 590 (2014) 163
[10] K. G. Prashanth et al. J. Mater. Res. 29 (2014) 2044
[11] P. F. Gostin et al. J. Mater Res. (accepted)
[12] R. Süptitz et al., Electrochimica Acta 109 (2013)
[13] A.Sobolkina et al. J. Colloid. Interface Sci. (2014) 413
[14] A. Kauffmann et al. Mater. Sci. Eng A (2015) accepted
Cooperations: Partners within the BMWi funded research LuFo: DLR, EADS, MTU,
Rolls-Royce; Partners within the BMWi funded research ZIM: TU Chemnitz, quada V+F;
Laserschweißdraht GmbH, LPT – Laserpräzisionstechnik GmbH; SWATCH; BOSCH;
WIWeB; DIEHL; UMICORE; The NANOSTEEL company; WIELANDWERKE; TU Dresden,
Institute of construction materials; IPF Dresden; University of Kaiserslautern and
members SPP 1594
Fig. 6: Optical micrograph of the surface of a bulk
glassy Fe 65.5 Cr4 Mo4 Ga 4 P12C 5 B 5.5 sample after an
electrochemical micromachining test in aqueous
sulphuric acid solution.
Research Topic 4.5
Concepts and materials for superconducting applications
People: A. Berger, D. Berger, T. Espenhahn, G. Fuchs, U. Gaitzsch, V. Grinenko, S. Hameister, J. Hänisch, W. Häßler,
B. Holzapfel, A. Horst, R. Hühne, A. Kirchner, K. Nenkov, P. Pahlke, E. Reich, T. Seidemann, M. Sieger, M. Sparing, A. Winkler
Responsible Director: L. Schultz
Summary: The unique properties of superconducting materials open the way to a wide
range of important applications e.g. in the fields of electronics, medicine, research and
energy. Low temperature superconducting materials like NbTi and Nb3 Sn are already
widely used as high field research magnets and moderate field MRI magnets for medical diagnostics. High temperature superconductors are now on the way to drastically
extend the application range towards power systems like motors, cables, fault current
limiters as well as ultra-high field magnets and levitation based applications. The
central aim of this research topic is to investigate superconducting materials and to
develop demonstrator systems that enable the realization of such new applications.
This covers the synthesis of high critical current conductors, the controlled pinning
enhancement by nano-engineering of superconductors and the realization of demonstration applications to study new technological directions.
Improved YBCO coated conductors
The main focus of our work in the last year was on the preparation of thick YBa2Cu3O7-x
layers with artificial pinning centers on metallic substrates. Therefore, we used highly
textured Ni-W templates with a W content of up to 9.5 at.% prepared by the rolling biaxially textured substrates (RABiTS) approach as well as ion-beam textured YSZ layers
on stainless steel. The superconducting layers were grown with pulsed laser deposition
in a high growth rate scheme. The main emphasis was on the incorporation of BaHfO3
nanoparticles with different volume content (Fig. 1). It was shown that a significant
improvement of the critical current density in magnetic fields Jc (B) was achieved using
this approach [1]. Alternatively, BaYNbTaO6 nanoparticles were embedded in films on
SrTiO3 single crystals. The formation of defined nanorods was observed leading to a
significant increase of the pinning for fields parallel to the c-axis.
MgB2 – Wires and permanent bulk magnets
An internal Magnesium diffusion described recently in literature was applied as a new
technology for the preparation of MgB2 -wires. This approach is based on diffusion of
metallic Magnesium in the surrounding Boron powder during heat treatment and gives
denser filaments in comparison to the classic in-situ technique as basis for higher
critical current densities. An engineering critical current density Je of 10 kA/cm2 at 4.2 K
and 5 T was achieved for mono-core wires. These parameters were recently transferred
to a seven filament wire.
Last year we reported on high trapped field values of 3.2 T at 15K measured in MgB2 bulk
samples of 1.5mm thickness (Fig. 2). In a study on the thickness dependence of trapped
fields we found that at high temperatures (T∼ 24 K) the optimum sample thickness is
∼ 1mm as for thicker samples only its outer part of ∼ 1 mm thickness contributes to the
trapped field due to the strong field dependence of the critical current density. At lower temperatures (T∼ 15K), an insufficient thermal stability prevents a simple thickness
scalability of the trapped field which is limited by flux jumps. To overcome this problem,
pairs of about 2 mm thick samples separated by a spacer will be used at 15K in order to
increase the trapped field available in a relative large volume between the two samples.
Fig. 1: TEM images of 2 mol% BHO:YBCO on Ni9W:
(a) coated conductor architecture; (b) c-axis oriented
nanorods of BaHfO3 (white arrows mark BHO
nanoparticles).
Superconducting motors and AC losses in YBCO coils
Pancake coils made from YBCO coated conductors have high critical currents and are
attractive for application in superconducting motors. However, the AC losses of YBCO
windings are at present too high, especially if the additional effort for the cooling
equipment is taken into account. The main contribution to the AC loss of YBCO coils is
the hysteretic loss in the superconductor, Physt ∝ Br3, which is basically determined by
the large radial component Br of the AC self-field in the coil. In superconducting transverse flux motors, a ring shaped double-pancake YBCO coil is used which is enclosed by
a soft magnetic yoke with a claw-pole structure. The magnetic flux travelling in transverse direction (perpendicular to the direction of rotation) acts as flux diverter and
slightly reduces the radial field in the YBCO coil. We have shown by FEM simulations that
this effect can be strongly enhanced by including two ferromagnetic foils close to the
plane face sides of the YBCO coil. From the simulations, a strong reduction of the radial
field Br by a factor of three is expected which would reduce the AC loss of the specific
motor considered here on values Physt ≤ 20 W.
Superconducting magnetic bearings in
rotating high-speed textile machines
Our research activities on small scale levitation applications properties are embedded in
the framework of a joint 3-year DFG project with the Institute of Textile Machinery and
High Performance Material Technology at the TU Dresden. The work is focused on the implementation and characterization of rotation ring-shaped superconducting magnetic
bearings (SMBs) in high-speed textile processing machines for the mass production of
short staple yarn. The majority of the short staple yarn produced worldwide today is spun
with the traditional ring spinning technique. The productivity of this process depends
on the rotational speed of the spindle. It is limited by friction in the so-called ringtraveler twist element (Fig. 3a). During the spinning process the traveler is dragged
along the ring-rail by the yarn with up to 30000 rpm. The resulting friction causes wear
of the twist element and melting of synthetic yarns at high spindle speeds due to strong
heat generation.
Fig. 2: Hot pressed MgB2 bulk sample used as
superconducting permanent magnet.
Fig. 3: (a) Conventional ring-traveler twist
element in ring spinning. The small c-shaped
traveler is dragged along the immobile ring by
the yarn. (b) Superconducting magnetic bearing
as twist element. The magnetic ring is rotated
by the yarn winding onto the spindle.
The replacement of the ring-traveler twist element by a superconducting magnetic
bearing was proposed to overcome this friction induced productivity limit [2]. SMBs are
inherently passive and contact-less bearings consisting, in this case, of a permanentmagnetic NdFeB ring acting as yarn driven traveler and a stationary superconducting
YBa2Cu3O 7-x ring cooled on 77 K in a cryostat (Fig. 3b). With a first prototype of our SMB
twist element in an open bath cryostat, several hundred meters of yarn were spun and
the yarn quality was found to be comparable to conventional ring spun yarn [3]. Therefore, a ring-shaped flow-through cryostat was developed and built in cooperation with
our industrial partner evico GmbH. Superconducting rings were assembled from preselected bulks, prepared at the IFW by a melt texturing technique. Simultaneously we
started to investigate experimentally as well as describe theoretically the static and
dynamic behavior of the SMB, e.g. forces, displacements and precession, with respect to
the ring spinning process [4].
Large Scale Application: SupraTrans II
Fig. 4: Model of an electromagnetic track using
superconducting tapes: (a) Field calculation by
FEM (Comsol); (b) Parts of the experimental
model; (c) schematic view of the assembled
experimental model.
After the completion, the test drive facility SupraTrans II is used now for scientific
investigation. Particular emphasis lies on the study of the behavior under practical operation conditions and the development of new components such as electromagnetic
tracks and fast switchable electromagnetic turnouts. First result of a PhD work on such
new system components is a model of an electromagnetic track using superconducting
tapes to create the magnetomotive force needed (Fig. 4). Simultaneously, the test
drive facility is used for a general dissemination of superconductivity to the wider public (pupils, students, vocational training etc.) as well as for professional presentations
to contact potential users of this new technology.
Furthermore, a PROBRAL-Project together with the Alberto Luiz Coimbra Institute for
Graduate Studies and Research in Engineering (COPPE) at the Federal University of Rio
de Janeiro was started in 2014. This institute opened its own straight outdoor superconductive levitation line, the MagLev Cobra. The aim of the exchange project is to
examine and compare the driveway characteristics of the the SupraTrans and the MagLev
Cobra, which are different in design, as well as to study the behavior of such systems for
an outdoor application and on curved tracks.
[1] M. Sieger et al., IEEE Trans. Appl. Supercond. 25 (2015)
DOI: 10.1109/TASC.2014.2372903
[2] C. Cherif et al. “Patent WO 2012/100964 A2, International, (2012)
[3] M. Hossain et al., Text. Res. J., 84 (2014) 871
[4] M. Sparing et al., IEEE Trans. Appl. Supercond. 25 (2015)
DOI: 10.1109/TASC.2014.2366001
Funding: EU (EuroTapes), DFG, BMBF (Project Diamant), DAAD PPP PROBRAL
Cooperations: Bruker HTS, Alzenau, Germany; THEVA GmbH, Ismaning, Germany;
University of Cambridge, United Kingdom; ICMAB Barcelona, Spain; University of
Vienna, Austria; COPPE/UFRJ, Rio de Janeiro, Brazil; evico GmbH, Dresden, Germany;
Institute of Textile Machinery and High Performance Material Technology at the TU
Dresden; Festo AG & Co KG, Esslingen, Germany; KIT, Karlsruhe, Germany; Siemens CT
Erlangen, Germany; IEE Bratislava (SAS), Slovakia
Publications 2014 83
Publications 2014
Monographs and Editorships
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Physics of quantum rings, V. Fomin (ed.); Berlin: Springer-Verl., Series: NanoScience and Technology, 2014, 310 S.
W. Kuch, R. Schaefer, P. Fischer, U. Hillebrecht, Magnetic microscopy of layered structures, Springer-Verl., 2014, 246 S.
J. Thomas, T. Gemming, Analytical transmission electron microscopy - An introduction for operators, Springer-Verl., 2014, 382 S.
Journal Papers
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M. Abdel-Hafiez, P.J. Pereira, S.A. Kuzmichev, T.E. Kuzmicheva, V.M. Pudalov, L. Harnagea, A.A. Kordyuk, A.V. Silhanek,
V.V. Moshchalkov, B. Shen, H.-H. Wen, A.N. Vasiliev, X.-J. Chen, Lower critical field and SNS- Andreev spectroscopy of 122-arsenides:
Evidence of nodeless superconducting gap, Physical Review B 90 (2014) Nr. 5, S. 54524/1-9.
S. Abdi, M. Samadi Khoshkhoo, O. Shuleshova, M. Boenisch, M. Calin, L. Schultz, J. Eckert, M.D. Baro, J. Sort, A. Gebert,
Effect of Nb addition on microstructure evolution and nanomechanical properties of a glass-forming Ti-Zr-Si alloy, Intermetallics 46
(2014), S. 156-163.
J. Akola, P. Jovari, I. Kaban, I. Voleska, J. Kolar, T. Wagner, R.O. Jones, Structure, electronic, and vibrational properties of
amorphous AsS2 and AgAsS2: Experimentally constrained density functional study, Physical Review B 89 (2014) Nr. 6, S. 64202/1-9.
F. Ali, S. Scudino, M.S. Anwar, R.N. Shahid, V.C. Srivastava, V. Uhlenwinkel, M. Stoica, G. Vaughan, J. Eckert, Al-based metal
matrix composites reinforced with Al-Cu-Fe quasicrystalline particles: Strengthening by interfacial reaction, Journal of Alloys and
Compounds 607 (2014), S. 274-279.
G. Allodi, R. De Renzi, K. Zheng, S. Sanna, A. Sidorenko, C. Baumann, L. Righi, F. Orlandi, G. Calestani, Band filling effect on
polaron localization in La1-x(CaySr1-y)xMnO3 manganites, Journal of Physics: Condensed Matter 26 (2014), S. 266004/1-16.
B. Anis, F. Boerrnert, M.H. Ruemmeli, C.A. Kuntscher, Optical microspectroscopy study of the mechanical stability of empty and
filled carbon nanotubes under hydrostatic pressure, The Journal of Physical Chemistry C 118 (2014), S. 27048-27062.
H. Attar, M. Boenisch, M. Calin, L.-C. Zhang, S. Scudino, J. Eckert, Selective laser melting of in situ titanium-titanium boride
composites: Processing, microstructure and mechanical properties, Acta Materialia 76 (2014), S. 13-22.
H. Attar, M. Boenisch, M. Calin, L.C. Zhang, K. Zhuravleva, A. Funk, S. Scudino, C. Yang, J. Eckert, Comparative study of
microstructures and mechanical properties of in situ Ti-TiB composites produced by selective laser melting, powder metallurgy,
and casting technologies, Journal of Materials Research 29 (2014), S. 1941-1950.
H. Attar, M. Calin, L.C. Zhang, S. Scudino, J. Eckert, Manufacture by selective laser melting and mechanical behavior of
commercially pure titanium, Materials Science and Engineering A 593 (2014), S. 170-177.
A. Bachmatiuk, R.F. Abelin, H.T. Quang, B. Trzebicka, J. Eckert, M.H. Ruemmeli, Chemical vapor deposition of twisted bilayer and
few-layer MoSe2 over SiO x substrates, Nanotechnology 25 (2014) Nr. 36, S. 365603/1-5.
A. Bachmatiuk, A. Dianat, F. Ortmann, H.T. Quang, M.O. Cichocka, I. Gonzalez-Martinez, L. Fu, B. Rellinghaus, J. Eckert,
G. Cuniberti, M.H. Ruemmeli, Graphene coatings for the mitigation of electron stimulated desorption and fullerene cap formation,
Chemistry of Materials 26 (2014), S. 4998-5003.
S.-H. Baek, R. Klingeler, C. Neef, C. Koo, B. Buechner, H.-J. Grafe, Unusual spin fluctuations and magnetic frustration in olivine
and non-olivine LiCoPO4 detected by 31P and 7Li nuclear magnetic resonance, Physical Review B 89 (2014) Nr. 13, S. 134424/1-6.
S.-H. Baek, L.M. Reinold, M. Graczyk-Zajacb, R. Riedel, F. Hammerath, B. Buechner, H.-J. Grafe, Lithium dynamics in carbon-rich
polymer-derived SiCN ceramics probed by nuclear magnetic resonance, Journal of Power Sources 253 (2014), S. 342-348.
S. Bahr, A. Alfonsov, G. Jackeli, G. Khaliullin, A. Matsumoto, T. Takayama, H. Takagi, B. Buechner, V. Kataev, Low-energy magnetic
excitations in the spin-orbital Mott insulator Sr2IrO4, Physical Review B 89 (2014) Nr. 18, S. 180401(R)/1-4.
N. Balchev, E. Nazarova, K. Buchkov, K. Nenkov, J. Pirov, B. Kunev, Effect of Sn-doping on the superconducting properties of
HoBa2Cu3Oy, obtained by the MTG method, Journal of Superconductivity and Novel Magnetism 27 (2014) Nr. 3, S. 763-769.
C. Balz, B. Lake, H. Luetkens, C. Baines, T. Guidi, M. Abdel-Hafiez, A.U.B. Wolter, B. Buechner, I.V. Morozov, E.B. Deeva,
O.S. Volkova, A.N. Vasiliev, Quantum spin chain as a potential realization of the Nersesyan-Tsvelik model, Physical Review B 90
(2014) Nr. 6, S. 60409(R)/1-5.
S. Bance, H. Oezelt, T. Schrefl, G. Ciuta, N.M. Dempsey, D. Givord, M. Winklhofer, G. Hrkac, G. Zimanyi, O. Gutfleisch,
T.G. Woodcock, T. Shoji, M. Yano, A. Kato, A. Manabe, Influence of defect thickness on the angular dependence of coercivity
in rare-earth permanent magnets, Applied Physics Letters 104 (2014), S. 182408/1-5.
K. Baroudi, C. Yim, H. Wu, Q. Huang, J.H. Roudebush, E. Vavilova, H.-J. Grafe, V. Kataev, B. Buechner, H. Ji, C. Kuo, C., Z. Hu,
T.-W. Pi, C. Pao, J. Lee, D. Mikhailova, L.H. Tjeng, R.J. Cava, Structure and propertie sof alpha—NaFeO2-type ternary sodium iridates,
Journal of Solid State Chemistry 210 (2014), S. 195-205.
K. Barros, J.W.F. Venderbos, G.-W. Chern, C.D. Batista, Exotic magnetic orderings in the kagome Kondo-lattice model,
Physical Review B 90 (2014), S. 245119/1-13.
M. Bartusch, M. Hetti, D. Pospiech, M. Riedel, J. Meyer, C. Toher, V. Neu, I. Gazuz, L.S. Shagolsem, J.-U. Sommer, R.-D. Hund,
C. Cherif, F. Moresco, G. Cuniberti, B. Voit, Innovative molecular design for a volume oriented component diagnostic: Modified magnetic nanoparticles on high performance yarns for smart textiles, Advanced Engineering Materials 16 (2014) Nr. 10, S. 1276-1283.
A. Bauer, A. Regnat, C.G.F. Blum, S. Gottlieb-Schoenmeyer, B. Pedersen, M. Meven, S. Wurmehl, J. Kunes, C. Pfleiderer,
Low-temperature properties of single-crystal CrB2, Physical Review B 90 (2014) Nr. 6, S. 64414/1-14.
J. Bielecki, A.D. Rata, L. Boerjesson, Femtosecond optical reflectivity measurements of lattice-mediated spin repulsions in
photoexcited LaCoO3 thin films, Physical Review B 89 (2014) Nr. 3, S. 35129/1-5.
84 Publications 2014
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T. Biemelt, C. Selzer, F. Schmidt, G. Mondin, A. Seifert, K. Pinkert, S. Spange, T. Gemming, S. Kaskel, Hierarchical porous zeolite
ZSM-58 derived by desilication and desilication re-assembly, Microporous and Mesoporous Materials 187 (2014), S. 114-124.
V. Bilovol, L.G. Pampillo, D. Meier, U. Wolff, F. Saccone, Cobalt ferrite films: Nanopolishing and magnetic properties,
IEEE Transactions on Magnetics 50 (2014) Nr. 9, S. 6000305/1-5.
V. Bisogni, S. Kourtis, C. Monney, K. Zhou, R. Kraus, C. Sekar, V. Strocov, B. Buechner, J. van den Brink, L. Braicovich, T. Schmitt,
M. Daghofer, J. Geck, Femtosecond dynamics of momentum-dependent magnetic excitations from resonant inelastic X-Ray scattering
in CaCu2O3, Physical Review Letters 112 (2014), S. 147401/1-5.
F. Bittner, S. Yin, A. Kauffmann, J. Freudenberger, H. Klauss, G. Korpala, R. Kawalla, W. Schillinger, L. Schultz, Dynamic
recrystallisation and precipitation behaviour of high strength and highly conducting Cu-Ag-Zr-alloys, Materials Science and
Engineering A 597 (2014), S. 139-147.
B. Boehme, C.B. Minella, F. Thoss, I. Lindemann, M. Rosenburg, C. Pistidda, C.T. Moeller, T.R. Jensen, L. Giebeler, M. Baitinger,
O. Gutfleisch, H. Ehrenberg, J. Eckert, Y. Grin, L. Schultz, B1 - Mobilstor: Materials for sustainable energy storage techniques Lithium containing compounds for hydrogen and electrochemical energy storage, Advanced Engineering Materials 16 (2014) Nr. 10,
S. 1183-1195.
M. Boenisch, M. Calin, L. Giebeler, A. Helth, A. Gebert, W. Skrotzki, J. Eckert, Composition-dependent magnitude of atomic
shuffles in Ti-Nb martensites, Journal of Applied Crystallography 47 (2014), S. 1374-1379.
F. Boerrnert, T. Riedel, H. Mueller, M. Linck, B. Buechner, H. Lichte, A dedicated In-situ off-axis electron holography (S)TEM:
Concept and electron-optical performance, Microscopy and Microanalysis 20 (2014) Nr. Suppl. 3, S. 1650-1651.
F. Boerrnert, R. Voigtlaender, B. Rellinghaus, B. Buechner, M.H. Ruemmeli, H. Lichte, A cheap and quickly adaptable in situ
electrical contacting TEM sample holder design, Ultramicroscopy 139 (2014), S. 1-4.
S. Boettner, S. Li, M.R. Jorgensen, O.G. Schmidt, Polarization resolved spatial near-field mapping of optical modes in an on-chip
rolled-up bottle microcavity, Applied Physics Letters 105 (2014), S. 121106/1-5.
C.C. Bof Bufon, C. Vervacke, D.J. Thurmer, M. Fronk, G. Salvan, S. Lindner, M. Knupfer, D.R.T. Zahn, O.G. Schmidt,
Determination of the charge transport mechanisms in ultrathin copper phthalocyanine vertical heterojunctions, The Journal of
Physical Chemistry C 118 (2014), S. 7272-7279.
A. Bogusz, A.D. Mueller, D. Blaschke, I. Skorupa, D. Buerger, A. Scholz, O.G. Schmidt, H. Schmidt, Resistive switching in
polycrystalline YMnO3 thin films, AIP Advances 4 (2014), S. 107135/1-8.
A. Bonatto Minella, D. Pohl, C. Taeschner, R. Erni, R. Ummethala, M.H. Ruemmeli, L. Schultz, B. Rellinghaus, Silicon carbide
embedded in carbon nanofibres: Structure and band gap determination, Physical Chemistry, Chemical Physics: PCCP 16 (2014),
S. 24437-24442.
C. Bonavolonta, C. de Lisio, M. Valentino, L. Parlato, G.P. Pepe, F. Kurth, K. Iida, Evaluation of superconducting gaps in optimally
doped Ba(Fe1xCox)2As2/Fe bilayers by ultrafast time-resolved spectroscopy, Physica C 503 (2014), S. 132-135.
L. Borchardt, M. Oschatz, S. Graetz, M.R. Lohe, M.H. Ruemmeli, S. Kaskel, A hard-templating route towards ordered mesoporous
tungsten carbide and carbide-derived carbons, Microporous and Mesoporous Materials 186 (2014), S. 163-167.
S. Borisenko, Q. Gibson, D. Evtushinsky, V. Zabolotnyy, B. Buechner, R.J. Cava, Experimental realization of a three-dimensional
dirac semimetal, Physical Review Letters 113 (2014) Nr. 2, S. 27603/1-.
V. Brackmann, V. Hoffmann, A. Kauffmann, A. Helth, J. Thomas, H. Wendrock, J. Freudenberger, T. Gemming, J. Eckert, Glow
discharge plasma as a surface preparation tool for microstructure investigations, Materials Characterization 91 (2014), S. 76-88.
J. Brand, A. Stunault, S. Wurmehl, L. Harnagea, B. Buechner, M. Meven, M. Braden, Spin susceptibility in superconducting LiFeAs
studied by polarized neutron diffraction, Physical Review B 89 (2014) Nr. 4, S. 45141/1-5.
M. Brehm, M. Grydlik, F. Schaeffler, O.G. Schmidt, Evolution and coarsening of Si-rich SiGe islands epitaxially grown at high
temperatures on Si(001), Microelectronic Engineering 125 (2014), S. 22-27.
N. Brun, K. Sakaushi, J. Eckert, M.M. Titirici, Carbohydrate-derived nanoarchitectures: On a synergistic effect toward an improved
performance in Lithium-Sulfur batteries, ACS Sustainable Chemistry and Engineering 2 (2014), S. 126-129.
W. Brzezicki, M. Daghofer, A.M. Ole, Mechanism of hole propagation in the orbital compass models, Physical Review B 89 (2014)
Nr. 2, S. 24417/1-11.
M. Calin, A. Helth, J.J. Gutierrez Moreno, M. Boenisch, V. Brackmann, L. Giebeler, T. Gemming, C.E. Lekka, A. Gebert,
R. Schnettler, J. Eckert, Elastic softening of Beta-type Ti-Nb alloys by indium (In) additions, Journal of the Mechanical Behavior
of Biomedical Materials 39 (2014), S. 162-174.
R.D. Cava, C. Bolfarini, C.S. Kiminami, E.M. Mazzer, W.J. Botta Filho, P. Gargarella, J. Eckert, Spray forming of
Cu-11.85Al-3.2Ni-3Mn (wt%) shape memory alloy, Journal of Alloys and Compounds 615 (2014) Nr. S1, S. S602-S606.
P. Cendula, A. Malachias, C. Deneke, S. Kiravittaya, O.G. Schmidt, Experimental realization of coexisting states of rolled-up and
wrinkled nanomembranes by strain and etching control, Nanoscale 6 (2014), S. 14326-14335.
A. Charnukha, Optical conductivity of iron-based superconductors, Journal of Physics: Condensed Matter 26 (2014) Nr. 25,
S. 253203/1-35.
A.K. Chaubey, S. Scudino, M. Samadi Khoshkhoo, K.G. Prashanth, N.K. Mukhopadhyay, B.K. Mishra, J. Eckert, High-strength
ultrafine grain Mg- 7.4% Al alloy synthesized by consolidation of mechanically alloyed powders, Journal of Alloys and Compounds
610 (2014), S. 456-461.
P. Chen, J.J. Zhang, J.P. Feser, F. Pezzoli, O. Moutanabbir, S. Cecchi, G. Isella, T. Gemming, S. Baunack, G. Chen, O.G. Schmidt,
A. Rastelli, Thermal transport through short-period SiGe nanodot superlattices, Journal of Applied Physics 115 (2014) Nr. 4,
S. 44312/1-10.
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A. Chikina, M. Hoeppner, S. Seiro, K. Kummer, S. Danzenbaecher, S. Patil, A. Generalov, M. Guettler, Y. Kucherenko, E.V. Chulkov,
Y.M. Koroteev, K. Koepernik, C. Geibel, M. Shi, M. Radovic, C. Laubschat, D.V. Vyalikh, Strong ferromagnetism at the surface of
an antiferromagnet caused by buried magnetic moments, nature communications 5 (2014), S. 4171/1-.
A.V. Chubukov, J.J. Betouras, D.V. Efremov, Non-Landau damping of magnetic excitations in systems with localized and itinerant
electrons, Physical Review Letters 112 (2014) Nr. 3, S. 37202/1-5.
M.O. Cichocka, J. Zhao, A. Bachmatiuk, H.T. Quang, S.M. Gorantla, I.G. Gonzalez-Martinez, L. Fu, J. Eckert, J.H. Warner, M.H.
Ruemmeli, In situ observations of Pt nanoparticles coalescing inside carbon nanotubes, RSC Advances 4 (2014), S. 49442-49445.
D. Comtesse, M.E. Gruner, M. Ogura, V.V. Sokolovskiy, V.D. Buchelnikov, A. Gruenebohm, R. Arroyave, N. Singh, T. Gottschall,
O. Gutfleisch, V.A. Chernenko, F. Albertini, S. Faehler, P. Entel, First-principles calculation of the instability leading to giant
inverse magnetocaloric effects, Physical Review B 89 (2014) Nr. 18, S. 184403/1-6.
M. Daghofer, M. Hohenadler, Phases of correlated spinless fermions on the honeycomb lattice, Physical Review B 89 (2014) Nr. 3,
S. 35103/1-3.
A.N. Darinskii, M. Weihnacht, H. Schmidt, Rayleigh wave scattering from a vertical edge of isotropic substrates, Ultrasonics 54
(2014), S. 1999-2005.
S. Das, A. Herklotz, E.J. Guo, K. Doerr, Static and reversible elastic strain effects on magnetic order of La0.7Ca0.3MnO3/SrTiO3
superlattices, Journal of Applied Physics 115 (2014) Nr. 14, S. 143902/1-5.
K. Davami, M. Shaygan, N. Kheirabi, J. Zhao, D.A. Kovalenko, M.H. Ruemmeli, J. Opitz, G. Cuniberti, J.-S. Lee, M. Meyyappan,
Synthesis and characterization of carbon nanowalls on different substrates by radio frequency plasma enhanced chemical vapor
deposition, Carbon 72 (2014), S. 372-380.
M. de Pauli, M.J.S. Matos, P.F. Siles, M.C. Prado, B.R.A. Neves, S.O. Ferreira, M.S.C. Mazzoni, A. Malachias, Chemical stabilization
and improved thermal resilience of molecular arrangements: Possible formation of a surface network of bonds by Multiple Pulse
Atomic Layer Deposition, The Journal of Physical Chemistry B 118 (2014), S. 9792-9799.
L. Ding, S. He, S. Miao, M.R. Jorgensen, S. Leubner, C. Yan, S.G. Hickey, A. Eychmueller, J. Xu, O.G. Schmidt, Ultrasmall SnO2
nanocrystals: Hot-bubbling synthesis, encapsulation in Carbon layers and applications in high capacity Li-Ion storage, Scientific
Reports 4 (2014), S. 4647/1-8.
I. Dirba, S. Sawatzki, O. Gutfleisch, Net-shape and crack-free production of Nd-Fe-B magnets by hot deformation, Journal of Alloys
and Compounds 589 (2014), S. 301-306.
G. Doerfel, Der Meister und seine Schule - Zur Biographie und Wirkung des Instrumentenbauers Heinrich Geissler, Sudhoffs Archiv Zeitschrift fuer Wissenschaftsgeschichte 98 (2014) Nr. 1, S. 91-108.
S. Doerfler, K. Pinkert, M. Weiser, C. Wabnitz, A. Goldberg, B. Ferse, L. Giebeler, H. Althues, M. Schneider, J. Eckert, A. Michaelis,
E. Beyer, S. Kaskel, D2 Enertrode: Production technologies and component integration of nanostructured carbon electrodes for
energy technology - Functionalized carbon materials for efficient electrical energy supply, Advanced Engineering Materials 16 (2014)
Nr. 10, S. 1196-1201.
S. Doering, M. Monecke, S. Schmidt, F. Schmidl, V. Tympel, J. Engelmann, F. Kurth, K. Iida, S. Haindl, I. Moench, B. Holzapfel,
P. Seidel, Investigation of TiO x barriers for their use in hybrid Josephson and tunneling junctions based on pnictide thin films,
Journal of Applied Physics 115 (2014), S. 83901/1-5.
P. Donnadieu, C. Pohlmann, S. Scudino, J.-J. Blandin, K.B. Surreddi, J. Eckert, Deformation at ambient and high temperature of
in situ Laves phases-ferrite composites, Science and Technology of Advanced Materials 15 (2014), S. 34801/1-8.
J. Dreiser, R. Westerstroem, C. Piamonteze, F. Nolting, S. Rusponi, H. Brune, S. Yang, A. Popov, L. Dunsch, T. Greber, X-ray induced
demagnetization of single-molecule magnets, Applied Physics Letters 105 (2014) Nr. 3, S. 32411/1-5.
J. Dreiser, R. Westerstroem, Y. Zhang, A.A. Popov, L. Dunsch, K. Kraemer, S.-X. Liu, S. Decurtins, T. Greber, The metallofullerene
field-induced single-ion magnet HoSc2N-at- C80, Chemistry - A European Journal 20 (2014) Nr. 42, S. 13536-13540.
N. Du, N. Manjunath, Y. Shuai, D. Buerger, I. Skorupa, R. Schueffny, C. Mayr, D.N. Basov, M. Di Ventra, O.G. Schmidt, H. Schmidt,
Novel implementation of memristive systems for data encryption and obfuscation, Journal of Applied Physics 115 (2014) Nr. 12,
S. 124501/1-7.
M. Emmel, A. Alfonsov, D. Legut, A. Kehlberger, E. Vilanova, I.P. Krug, D.M. Gottlob, M. Belesi, B. Buechner, M. Klaeui,
P.M. Oppeneer, S. Wurmehl, H.J. Elmers, G. Jakob, Electronic properties of Co2FeSi investigated by X-raymagnetic linear dichroism,
Journal of Magnetism and Magnetic Materials 368 (2014), S. 364-373.
P. Entel, M.E. Gruner, D. Comtesse, V.V. Sokolovskiy, V.D. Buchelnikov, Interacting magnetic cluster-spin glasses and strain glasses
in Ni–Mn based Heusler structured intermetallics, Physica Status Solidi B 251 (2014) Nr. 10, S. 2135-2148.
D. Ernst, M. Melzer, D. Makarov, F. Bahr, W. Hofmann, O.G. Schmidt, T. Zerna, Packaging technologies for (Ultra-)thin sensor
applications in active magnetic bearings, 37th International Spring Seminar on Electronics Technology (ISSE), in: Proceedings,
125-129 (2014).
A. Eschke, J. Scharnweber, C.-G. Oertel, W. Skrotzki, T. Marr, J. Romberg, J. Freudenberger, L. Schultz, I. Okulov, U. Kuehn,
J. Eckert, Texture development in Ti/Al filament wires produced by accumulative swaging and bundling, Materials Science and
Engineering A 607 (2014), S. 360-367.
A. Eschke, W. Zinn, T. Marr, C.-G. Oertel, W. Skrotzki, L. Schultz, J. Eckert, Local stress gradients in Ti/Al composite wires
determined by two-dimensional X-ray microdiffraction, Materials Science and Engineering A 616 (2014), S. 44-54.
D.V. Evtushinsky, V.B. Zabolotnyy, T.K. Kim, A.A. Kordyuk, A.N. Yaresko, J. Maletz, S. Aswartham, S. Wurmehl, A.V. Boris,
D.L. Sun, C.T. Lin, B. Shen, H.H. Wen, A. Varykhalov, R. Follath, B. Buechner, S.V. Borisenko, Strong electron pairing at the iron
3dxz, yz orbitals in hole-doped BaFe2As2 superconductors revealed by angle-resolved photoemission spectroscopy, Physical Review B
89 (2014) Nr. 6, S. 64514/1-12.
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A.V. Fedorov, N.I. Verbitskiy, D. Haberer, C. Struzzi, L. Petaccia, D. Usachov, O.Y. Vilkov, D.V. Vyalikh, J. Fink, M. Knupfer,
B. Buechner, A. Grueneis, Observation of a universal donor-dependent vibrational mode in graphene, nature communications 5
(2014), S. 3257/1-8.
74) P. Feng, G. Wu, O.G. Schmidt, Y. Mei, Photosensitive hole transport in Schottky-contacted Si nanomembranes, Applied Physics
Letters 105 (2014) Nr. 12, S. 121101/1-5.
75) P.P. Ferguson, D.-B. Leb, A.D.W. Todd, M.L. Martine, S. Trussler, M.N. Obrovac, J.R. Dahn, Nanostructured Sn30Co30C40 alloys
for lithium-ion battery negative electrodes prepared by horizontal roller milling, Journal of Alloys and Compounds 595 (2014),
S. 138-141.
76) P.P. Ferguson, A.D.W. Todd, M.L. Martine, J.R. Dahn, Structure and performance of Tin-Cobalt-Carbon alloys prepared by attriting,
roller milling and sputtering, Journal of The Electrochemical Society 161 (2014), S. A342-A347.
77) V.V. Fisun, O.P. Balkashin1, O.E. Kvitnitskaya, I.A. Korovkin, N.V. Gamayunova, S. Aswartham, S. Wurmehl, Y.G. Naidyuk,
Josephson effect and Andreev reflection in Ba1 -xNaxFe2As2 (x50.25 and 0.35) point contacts, Low Temperature Physics 40 (2014)
Nr. 10, S. 919-924.
78) V.M. Fomin, M. Hippler, V. Magdanz, L. Soler, S. Sanchez, O.G. Schmidt, Propulsion mechanism of catalytic microjet engines,
IEEE Transactions on Robotics 30 (2014) Nr. 1, S. 40-48.
79) Y. Fuji, S. Nishimoto, H. Nakada, M. Oshikawa, Quantum criticality in an asymmetric three-leg spin tube: A strong rung-coupling
perspective, Physical Review B 89 (2014) Nr. 5, S. 54425/1-13.
80) I. Galkina, A. Tufatullin, D. Krivolapov, Y. Bakhtiyarova, D. Chubukaeva, V. Stakheev, V. Galkin, R. Cherkasov, B. Buechner,
O. Kataeva, Crystal structure of phosphonium carboxylate complexes. The role of the metal coordination geometry, ligand
conformation and hydrogen bonding, CrystEngComm 16 (2014), S. 9010-9024.
81) R. Ganesh, G. Baskaran, J. van den Brink, D.V. Efremov, Theoretical prediction of a time-reversal broken chiral superconducting
phase driven by electronic correlations in a single TiSe2 layer, Physical Review Letters 113 (2014) Nr. 17, S. 177001/1-5.
82) J. Gao, P. Ngene, M. Herrich, W. Xia, O. Gutfleisch, M. Muhler, K.P. de Jong, P.E. de Jongh, Interface effects in NaAlH4-carbon
nanocomposites for hydrogen storage, International Journal of Hydrogen Energy 39 (2014) Nr. 19, S. 10175-10183.
83) P. Gargarella, S. Pauly, M. Samadi Khoshkhoo, U. Kuehn, J. Eckert, Phase formation and mechanical properties of Ti-Cu-Ni-Zr bulk
metallic glass composites, Acta Materialia 65 (2014), S. 259-269.
84) C. Gautham, D.W. Snoke, A. Rastelli, O.G. Schmidt, Time-resolved two-photon excitation of dark states in quantum dots,
Applied Physics Letters 104 (2014) Nr. 14, S. 143114/1-4.
85) A. Gebert, P.F. Gostin, R. Sueptitz, S. Oswald, S. Abdi, M. Uhlemann, J. Eckert, Polarization studies of Zr-based bulk metallic
glasses for electrochemical machining, Journal of The Electrochemical Society 161 (2014), S. E66-E73.
86) D. Geissler, J. Freudenberger, A. Kauffmann, S. Martin, D. Rafaja, Assessment of the thermodynamic dimension of the stacking
fault energy, Philosophical Magazine 94 (2014) Nr. 26, S. 2967-2979.
87) F. German, A. Hintennach, A. LaCroix, D. Thiemig, S. Oswald, F. Scheiba, M.J. Hoffmann, H. Ehrenberg, Influence of temperature
and upper cut-off voltage on the formation of lithium-ion cells, Journal of Power Sources 264 (2014), S. 100-107.
88) Q.D. Gibson, D. Evtushinsky, A.N. Yaresko, V.B. Zabolotnyy, M.N. Ali, M.K. Fuccillo, J. van den Brink, B. Buechner, R.J. Cava,
S.V. Borisenko, Quasi one dimensional dirac electrons on the surface of Ru2Sn3, Scientific Reports 4 (2014), S. 5168/1-6.
89) S. Giudicatti, S.M. Marz, L. Soler, A. Madani, M.R. Jorgensen, S. Sanchez, O.G. Schmidt, Photoactive rolled-up TiO2 microtubes:
Fabrication, characterization and applications, Journal of Materials Chemistry C 2 (2014), S. 5892-5901.
90) M. Gong, B. Hofer, E. Zallo, R. Trotta, J.-W. Luo, O.G. Schmidt, C. Zhang, Statistical properties of exciton fine structure splitting
and polarization angles in quantum dot ensembles, Physical Review B 89 (2014) Nr. 20, S. 205312/1-6.
91) C. Gonzalez-Gago, P. Smid, T. Hofmann, C. Venzago, V. Hoffmann, W. Gruner, The use of matrix-specific calibrations for oxygen in
analytical glow discharge spectrometry, Analytical and Bioanalytical Chemistry 406 (2014), S. 7473-7482.
92) I.G. Gonzalez-Martinez, S.M. Gorantla, A. Bachmatiuk, V. Bezugly, J. Zhao, T. Gemming, J. Kunstmann, J. Eckert, G. Cuniberti,
M.H. Ruemmeli, Room temperature in situ growth of B/BOx nanowires and BOx nanotubes, Nano Letters 14 (2014), S. 799-805.
93) S. Gorantla, A. Bachmatiuk, J. Hwang, H.A. Alsalman, J.Y. Kwak, T. Seyller, J. Eckert, M.G. Spencer, M.H. Ruemmeli, A universal
transfer route for graphene, Nanoscale 6 (2014), S. 889-896.
94) P.F. Gostin, H. Wendrock, I. Schneider, M. Bleckmann, M. Stoica, U. Kuehn, J. Eckert, Microstructure and mechanical properties
of a newly developed high strength Mg54.7Cu11.5Ag3.3Gd5.5Sc25 alloy, Intermetallics 45 (2014), S. 84-88.
95) H.-J. Grafe, U. Graefe, A.P. Dioguardi, N.J. Curro, S. Aswartham, S. Wurmehl, B. Buechner, Identical spin fluctuations in Cu- and
Co- doped BaFe2As2 independent of electron doping, Physical Review B 90 (2014) Nr. 9, S. 94519/1-8.
96) D. Grimm, R.B. Wilson, B. Teshome, S. Gorantla, M.H. Ruemmeli, T. Bublat, E. Zallo, G. Li, D.G. Cahill, O.G. Schmidt, Thermal
conductivity of mechanically joined semiconducting/metal nanomembrane superlattices, Nano Letters 14 (2014), S. 2387-2393.
97) V. Grinenko, D.V. Efremov, S.-L. Drechsler, S. Aswartham, D. Gruner, M. Roslova, I. Morozov, K. Nenkov, S. Wurmehl, A.U.B. Wolter,
B. Holzapfel, B. Buechner, Superconducting specific-heat jump delta Cel - Tc beta (beta-2) for K1-x NaxFe2As2, Physical Review B 89
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98) V. Grinenko, W. Schottenhamel, A.U.B. Wolter, D.V. Efremov, S.-L. Drechsler, S. Aswartham, M. Kumar, S. Wurmehl, M. Roslova,
I.V. Morozov, B. Holzapfel, B. Buechner, E. Ahrens, S.I. Troyanov, S. Koehler, E. Gati, S. Knoener, N.H. Hoang, M. Lang, F. Ricci,
G. Profeta, Superconducting properties of K1-xNaxFe2As2 under pressure, Physical Review B 90 (2014) Nr. 9, S. 94511/1-12.
99) M.E. Gruner, S. Faehler, P. Entel, Magnetoelastic coupling and the formation of adaptive martensite in magnetic shape memory
alloys, Physica Status Solidi B 251 (2014) Nr. 10, S. 2067-2079.
100) J. Gubicza, Z. Hegedus, J.L. Labar, V. Subramanya Sarma, A. Kauffmann, J. Freudenberger, Microstructure evolution during
annealing of an SPD processed supersaturated Cu- 3 at, % Ag alloy, IOP Conference Series: Materials Science and Engineering 63
(2014), S. 12091/1-9.
101) M. Guenther, S. Kamusella, R. Sarkar, T. Goltz, H. Luetkens, G. Pascua, S.-H. Do, K.-Y. Choi, H.D. Zhou, C.G.F. Blum, S. Wurmehl,
B. Buechner, H.-H. Klauss, Magnetic order and spin dynamics in La2O2Fe2OSe2 probed by 57Fe Moessbauer, 139La NMR, and
muon-spin relaxation spectroscopy, Physical Review B 90 (2014) Nr. 18, S. 184408/1-8.
102) E.J. Guo, S. Das, A. Herklotz, Enhancement of switching speed of BiFeO3 capacitors by magnetic fields, APL Materials 2 (2014),
S. 96107/1-8.
103) E.J. Guo, R. Roth, S. Das, K. Doerr, Strain induced low mechanical switching force in ultrathin PbZr0.2Ti0.8O3 films, Applied Physics
Letters 105 (2014) Nr. 1, S. 12903/1-5.
104) F. Haag, D. Beitelschmidt, J. Eckert, K. Durst, Influences of residual stresses on the serrated flow in bulk metallic glass under
elastostatic four-point bending – A nanoindentation and atomic force microscopy study, Acta Materialia 70 (2014), S. 188-197.
105) J. Haenisch, K. Iida, F. Kurth, T. Thersleff, S. Trommler, E. Reich, R. Huehne, L. Schultz, B. Holzapfel, The effect of 45° grain
boundaries and associated Fe particles on Jc and resistivity in Ba(Fe0.9Co0.1)2As2 thin films, AIP Conference Proceedings 1574
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106) F. Haidu, G. Salvan, D.R.T. Zahn, L. Smykalla, M. Hietschold, M. Knupfer, Transport band gap opening at metal-organic interfaces,
Journal of Vacuum Science and Technology A 32 (2014) Nr. 4, S. 40602/1-8.
107) S. Haindl, M. Kidszun, S. Oswald, C. Hess, B. Buechner, S. Koelling, L. Wilde, T. Thersleff, V.V. Yurchenko, M. Jourdan,
H. Hiramatsu, H. Hosono, Thin film growth of Fe-based superconductors: From fundamental properties to functional devices.
A comparative review, Reports on Progress in Physics 77 (2014), S. 46502/1-32.
108) C. Hamann, R. Mattheis, I. Moench, J. Fassbender, L. Schultz, J. McCord, Magnetization dynamics of magnetic domain wall
imprinted magnetic films, New Journal of Physics 16 (2014), S. 23010/1-12.
109) F. Hammerath, E.M. Bruening, S. Sanna, Y. Utz, N.S. Beesetty, R. Saint-Martin, A. Revcolevschi, C. Hess, B. Buechner, H.-J. Grafe,
Spin gap in the single spin-12 chain cuprate Sr1.9Ca0.1CuO3, Physical Review B 89 (2014) Nr. 18, S. 184410/1-5.
110) J.H. Han, N. Mattern, U. Vainio, A. Shariq, S.W. Sohn, D.H. Kim, J. Eckert, Phase separation in Zr56-xGdxCo28Al16 metallic glasses
(0< x < 20), Acta Materialia 66 (2014), S. 262-272.
111) A. Helth, P.F. Gostin, S. Oswald, H. Wendrock, U. Wolff, U. Hempel, S. Arnhold, M. Calin, J. Eckert, A. Gebert, Chemical nanoroughening of Ti40Nb surfaces and its effect on human mesenchymal stromal cell response, Journal of Biomedical Materials
Research, Part B - Applied Biomaterials 102 B (2014), S. 31-41.
112) N. Heming, U. Treske, M. Knupfer, B. Buechner, D.S. Inosov, N.Y. Shitsevalova, V.B. Filipov, S. Krause, A. Koitzsch,
Surface properties of SmB6 from x-ray photoelectron spectroscopy, Physical Review B 90 (2014) Nr. 19, S. 195128/1-7.
113) C. Hengst, M. Wolf, R. Schaefer, L. Schultz, J. McCord, Acoustic-domain resonance mode in magnetic closure-domain structures:
A probe for domain-shape characteristics and domain-wall transformations, Physical Review B 89 (2014) Nr. 21, S. 214412/1-6.
114) A. Herklotz, M.D. Biegalski, H.M. Christen, E.-J. Guo, K. Nenkov, A.D. Rata, L. Schultz, K. Doerr, Strain response of magnetic order
in perovskite-type oxide films, Philosophical Transactions of the Royal Society A 372 (2014), S. 20120441/ 1-12.
115) M. Herklotz, F. Scheiba, R. Glaum, E. Mosymow, S. Oswald, J. Eckert, H. Ehrenberg, Electrochemical oxidation of trivalent chromium
in a phosphatematrix: Li3Cr2(PO4)3as cathode material for lithium ion batteries, Electrochimica Acta 139 (2014), S. 356-364.
116) H. Hermann, Sung Nok Chiu et al.: Stochastic geometry and its applications, Physik-Journal (2014) Nr. 9, S. 75.
117) H. Hermann, A. Elsner, Geometric models for isotropic random porous media: A review, Advances in Materials Science and
Engineering (2014), S. 1-16.
118) H. Hermann, U. Kuehn, H. Wendrock, V. Kokotin, B. Schwarz, Evidence for cooling-rate-dependent icosahedral short-range order
in a Cu-Zr-Al metallic glass, Journal of Applied Crystallography 47 (2014), S. 1906-1911.
119) A.-K. Herrmann, P. Formanek, L. Borchardt, M. Klose, L. Giebeler, J. Eckert, S. Kaskel, N. Gaponik, A. Eychmueller, Multimetallic
aerogels by template-free self-assembly of Au, Ag, Pt, and Pd nanoparticles, Chemistry of Materials 26 (2014), S. 1074-1083.
120) C. Hoffmann, T. Biemelt, M.R. Lohe, M.H. Ruemmeli, S. Kaskel, Nanoporous and highly active Silicon carbide supported
CeO2-catalysts for the Methane oxidation reaction, Small 10 (2014), S. 316-322.
121) M. Hossain, A. Abdkader, C. Cherif, M. Sparing, D. Berger, G. Fuchs, L. Schultz, Innovative twisting mechanism based on
superconducting technology in a ring-spinning system, Textile Research Journal 84 (2014) Nr. 8, S. 871-880.
122) L. Hozoi, H. Gretarsson, J.P. Clancy, B.-G. Jeon, B. Lee, K.H. Kim, V. Yushankhai, P. Fulde, D. Casa, T. Gog, J. Kim, A.H. Said,
M.H. Upton, Y.-J. Kim, J. van den Brink, Longer-range lattice anisotropy strongly competing with spin-orbit interactions in
pyrochlore iridates, Physical Review B 89 (2014) Nr. 11, S. 115111/1-6.
123) G. Hrkac, K. Butler, T.G. Woodcock, L. Saharan, T. Schrefl, O. Gutfleisch, Modeling of Nd-Oxide grain boundary phases in
Nd-Fe-B sintered magnets, JOM 66 (2014) Nr. 7, S. 1138-1143.
124) G. Hrkac, T.G. Woodcock, K.T. Butler, L. Saharan, M.T. Bryan, T. Schrefl, O. Gutfleisch, Impact of different Nd-rich crystal-phases
on the coercivity of Nd-Fe-B grain ensembles, Scripta Materialia 70 (2014), S. 35-38.
125) Y.H. Huo, V. Krapek, A. Rastelli, O.G. Schmidt, Volume dependence of excitonic fine structure splitting in geometrically similar
quantum dots, Physical Review B 90 (2014) Nr. 4, S. 41304(R)/1-4.
126) Y.H. Huo, B.J. Witek, S. Kumar, J.R. Cardenas, J.X. Zhang, N. Akopian, R. Singh, E. Zallo, R. Grifone, D. Kriegner, R. Trotta, F. Ding,
J. Stangl, V. Zwiller, G. Bester, A. Rastelli, O.G. Schmidt, A light-hole exciton in a quantum dot, nature physics 10 (2014), S. 46-51.
127) V. Hutanu, A.P. Sazonov, M. Meven, G. Roth, A. Gukasov, H. Murakawa, Y. Tokura, D. Szaller, S. Bordacs, I. Kezsmarki, V.K. Guduru,
L.C.J.M. Peters, U. Zeitler, J. Romhanyi, B. Nafradi, Evolution of two-dimensional antiferromagnetism with temperature and
magnetic field in multiferroic Ba2CoGe2O7, Physical Review B 89 (2014) Nr. 6, S. 64403/1-9.
128) A. Ichinose, I. Tsukada, F. Nabeshima, Y. Imai, A. Maeda, F. Kurth, B. Holzapfel, K. Iida, S. Ueda, M. Naito, Induced lattice strain in
epitaxial Fe-based superconducting films on CaF2 substrates: A comparative study of the microstructures of SmFeAs(O,F),
Ba(Fe,Co)2As2, and FeTe0.5Se0.5, Applied Physics Letters 104 (2014) Nr. 12, S. 122603/1-5.
129) K.R. Idzik, T. Licha, V. Lukes, P. Rapta, J. Frydel, M. Schaffer, E. Taeuscher, R. Beckert, L. Dunsch, Synthesis and optical properties
of various thienyl derivatives of pyrene, Journal of Fluorescence 24 (2014) Nr. 1, S. 153-160.
130) B. Idzikowski, Z. Sniadecki, M. Reiffers, U.K. Roessler, Glass-forming ability for selected quasi-ternary metallic system:
Magnetism and heat capacity, Journal of Non-Crystalline Solids 383 (2014), S. 2-5.
131) K. Iida, F. Kurth, M. Chihara, N. Sumiya, V. Grinenko, A. Ichinose, I. Tsukada, J. Haenisch, V. Matias, T. Hatano, B. Holzapfel,
H. Ikuta, Highly textured oxypnictide superconducting thin films on metal substrates, Applied Physics Letters 105 (2014) Nr. 17,
S. 172602/1-.
132) J.J. Ipus, J.S. Blazquez, V. Franco, M. Stoica, A. Conde, Milling effects on magnetic properties of melt spun Fe-Nb-B alloy, Journal
of Applied Physics 115 (2014) Nr. 17, S. 17B518/1-3.
133) F.A. Javid, N. Mattern, M. Samadi Khoshkhoo, M. Stoica, S. Pauly, J. Eckert, Phase formation of Cu50xCoxZr50 (x = 0–20 at.%)
alloys: Influence of cooling rate, Journal of Alloys and Compounds 590 (2014), S. 428-434.
134) Y. Jia, F. Cao, S. Scudino, P. Ma, H. Li, L. Yu, J. Eckert, J. Sun, Microstructure and thermal expansion behavior of spray-deposited
Al–50Si, Materials and Design 57 (2014), S. 585-591.
135) L. Jin, Y. Shuai, X. Ou, P.F. Siles, H.Z. Zeng, T. You, N. Du, D. Buerger, I. Skorupa, S. Zhou, W.B. Luo, C.G. Wu, W.L. Zhang,
T. Mikolajick, O.G. Schmidt, H. Schmidt, Resistive switching in unstructured, polycrystalline BiFeO3 thin films with downscaled
electrodes, Physica Status Solidi A 211 (2014) Nr. 11, S. 2563-2568.
136) Y.I. Joe, X.M. Chen, P. Ghaemi1, K.D. Finkelstein, G.A. de la Pena, Y. Gan, J.C.T. Lee, S. Yuan, J. Geck, G.J. MacDougall, T.C. Chiang,
S.L. Cooper, E. Fradkin, P. Abbamonte, Emergence of charge density wave domain walls above the superconducting dome in 1T-TiSe2,
nature physics 10 (2014), S. 421-425.
137) S. Johnston, M. Abdel-Hafiez, L. Harnagea, V. Grinenko, D. Bombor, Y. Krupskaya, C. Hess, S. Wurmehl, A.U.B. Wolter,
B. Buechner, H. Rosner, S.-L. Drechsler, Specific heat of Ca0.32Na0.68Fe2As2 single crystals: Unconventional s +- multiband
superconductivity with intermediate repulsive interband coupling and sizable attractive intraband couplings, Physical Review B 89
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138) P. Jovari, P. Lucas, Z. Yang, B. Bureau, I. Kaban, B. Beuneu, J. Bednarcik, Short-range order in Ge-As-Te glasses, Journal of the
American Ceramic Society 97 (2014) Nr. 5, S. 1625-1632.
139) H.Y. Jung, M. Stoica, S. Yi, D.H. Kim, J. Eckert, Electrical and magnetic properties of Fe-based bulk metallic glass with minor Co
and Ni addition, Journal of Magnetism and Magnetic Materials 364 (2014), S. 80-84.
140) H.Y. Jung, S. Yi, Nanocrystallization and soft magnetic properties of Fe23M6 (M: C or B) phase in Fe-based bulk metallic glass,
Intermetallics 49 (2014), S. 18-22.
141) S. Just, S. Zimmermann, V. Kataev, B. Buechner, M. Pratzer, M. Morgenstern, Preferential antiferromagnetic coupling of
vacancies in graphene on SiO2: Electron spin resonance and scanning tunneling spectroscopy, Physical Review B 90 (2014) Nr. 12,
S. 125449/1-9.
142) I. Kaban, P. Jovari, A. Waske, M. Stoica, J. Bednarcik, B. Beuneu, N. Mattern, J. Eckert, Atomic structure and magnetic properties
of Fe-Nb-B metallic glasses, Journal of Alloys and Compounds 586 (2014) Nr. Suppl. 1, S. S189-S193.
143) I. Kaban, K. Khalouk, F. Gasser, J.-G. Gasser, J. Bednarcik, O. Shuleshova, I. Okulov, T. Gemming, N. Mattern, J. Eckert,
In situ studies of temperature-dependent behaviour and crystallisation of Ni36.5Pd36.5P27 metallic glass, Journal of Alloys
and Compounds 615 (2014), S. S208-S212.
144) M. Kalbac, V. Vales, L. Kavan, L. Dunsch, Doping of C70 fullerene peapods with lithium vapor: Raman spectroscopic and Raman
spectroelectrochemical studies, Nanotechnology 25 (2014) Nr. 48, S. 485706/1-7.
145) D. Karnaushenko, D. Makarov, M. Stoeber, D.D. Karnaushenko, S. Baunack, O.G. Schmidt, High-performance magnetic sensorics
for printable and flexible electronics, Advanced Materials online first (2014).
146) F. Karnbach, M. Uhlemann, A. Gebert, J. Eckert, K. Tschulik, Magnetic field templated patterning of the soft magnetic alloy CoFe,
Electrochimica Acta 123 (2014), S. 477-484.
147) T. Kaspar, J. Fiedler, I. Skorupa, D. Buerger, O.G. Schmidt, H. Schmidt, Transport in ZnCoO thin films with stable bound magnetic
polarons, APL Materials 2 (2014), S. 76101/1-7.
148) S.O. Katterwe, T. Jacobs, A. Maljuk, V.M. Krasnov, Low anisotropy of the upper critical field in a strongly anisotropic layered
cuprate Bi2.15Sr1.9CuO6+ delta: Evidence for a paramagnetically limited superconductivity, Physical Review B 89 (2014) Nr. 21,
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149) V.M. Katukuri, S. Nishimoto, V. Yushankhai, A. Stoyanova, H. Kandpal, S. Choi, R. Coldea, I. Rousochatzakis, L. Hozoi, J. van den
Brink, Kitaev interactions between j = 1/2 moments in honeycomb Na2IrO3 are large and ferromagnetic: Insights from ab initio
quantum chemistry calculations, New Journal of Physics 16 (2014), S. 13056/1-13.
150) V.M. Katukuri, V. Yushankhai, L. Siurakshina, J. van den Brink, L. Hozoi, I. Rousochatzakis, Mechanism of Basal-Plane antiferromagnetism in the Spin-Orbit driven Iridate Ba2IrO4, Physical Review X 4 (2014), S. 21051/1-10.
151) V.M. Katukuri, K. Roszeitis, V. Yushankhai, A. Mitrushchenkov, H. Stoll, M. van Veenendaal, P. Fulde, J. van den Brink, L. Hozoi,
Electronic structure of low-dimensional 4d5 oxides: Interplay of ligand distortions, overall lattice anisotropy, and spin-orbit
interactions, Inorganic Chemistry 53 (2014), S. 4833-4839.
152) S. Kauffmann-Weiss, S. Hamann, L. Reichel, A. Siegel, V. Alexandrakis, R. Heller, L. Schultz, A. Ludwig, S. Faehler, The Bain library:
A Cu-Au buffer template for a continuous variation of lattice parameters in epitaxial films, APL Materials 2 (2014), S. 46107/1-6.
153) D. Keller, S. Buecheler, P. Reinhard, F. Pianezzi, D. Pohl, A. Surrey, B. Rellinghaus, R. Erni, A.N. Tiwari, Local band gap
measurements by VEELS of thin film solar cells, Microscopy and Microanalysis 20 (2014), S. 1246-1253.
154) I.S.M. Khalil, V. Magdanz, S. Sanchez, O.G. Schmidt, S. Misra, The control of self-propelled microjets inside a microchannel with
time-varying flow rates, IEEE Transactions on Robotics 30 (2014) Nr. 1, S. 49-58.
155) I.S.M. Khalil, V. Magdanz, S. Sanchez, O.G. Schmidt, S. Misra, Wireless magnetic-based closed-loop control of self-propelled
microjets, PLOS one 9 (2014) Nr. 2, S. e83053/1-6.
156) I.S.M. Khalil, V. Magdanz, S. Sanchez, O.G. Schmidt, S. Misra, Biocompatible, accurate, and fully autonomous: A sperm-driven
micro-bio-robot, Journal of Micro-Bio Robotics 9 (2014) Nr. 3-4, S. 79-86.
157) S.M. Khoshkhoo, S. Scudino, J. Bednarcik, A. Kauffmann, H. Bahmanpour, J. Freudenberger, R. Scattergood, M.J. Zehetbauer,
C.C. Koch, J. Eckert, Mechanism of nanostructure formation in ball-milled Cu and Cu–3wt%Zn studied by X-ray diffraction line profile
analysis, Journal of Alloys and Compounds 588 (2014), S. 138-143.
158) W. Kicinski, M. Bystrzejewski, M.H. Ruemmeli, T. Gemming, Porous graphitic materials obtained from carbonization of organic
xerogels doped with transition metal salts, Bulletin of Materials Science 37 (2014) Nr. 1, S. 141-150.
159) J. Kim, M. Daghofer, A.H. Said, T. Gog, J. van den Brink, G. Khaliullin, B.J. Kim, Excitonic quasiparticles in a spin-orbit Mott
insulator, nature communications 5 (2014), S. 4453/1-6.
160) M. Klose, I. Lindemann, C. Bonatto Minella, K. Pinkert, M. Zier, L. Giebeler, P. Nolis, M.D. Baro, S. Oswald, O. Gutfleisch,
H. Ehrenberg, J. Eckert, Unusual oxidation behavior of light metal hydride by tetrahydrofuran solvent molecules confined in
ordered mesoporous carbon, Journal of Materials Research 29 (2014) Nr. 1, S. 55-63.
161) M. Klose, K. Pinkert, M. Zier, M. Uhlemann, F. Wolke, T. Jaumann, P. Jehnichen, D. Wadewitz, S. Oswald, J. Eckert, L. Giebeler, Hollow carbon nano-onions with hierarchical porosity derived from commercial metal organic framework, Carbon 79 (2014), S. 302-309.
162) B. Koch, S. Sanchez, C.K. Schmidt, A. Swiersy, S.P. Jackson, O.G. Schmidt, Confi nement and deformation of single cells and their
nuclei inside size-adapted microtubes, Advanced Healthcare Materials 3 (2014), S. 1753-1758.
163) M. Kohl, M. Schmitt, A. Backen, L. Schultz, B. Krevet, S. Faehler, Ni-Mn-Ga shape memory nanoactuation, Applied Physics Letters
104 (2014) Nr. 4, S. 43111/1-5.
164) A. Krause, W.M. Weber, Pohl D., B. Rellinghaus, M. Verheijen, T. Mikolajick, Investigation of embedded perovskite nanoparticles
for enhanced capacitor permittivities, ACS Applied Materials and Interfaces 6 (2014), S. 19737-19743.
165) K.J. Krause, K. Mathwig, B. Wolfrum, S.G. Lemay, Brownian motion in electrochemical nanodevices, The European Physical Journal
Special Topics 223 (2014) Nr. 14, S. 3165-3178.
166) M. Krautz, J. Hosko, K. Skokov, P. Svec, M. Stoica, L. Schultz, J. Eckert, O. Gutfleisch, A. Waske, Pathways for novel magnetocaloric
materials: A processing prospect, Physica Status Solidi (c) 11 (2014) Nr. 5-6, S. 1039-1042.
167) S. Kudela, K. Izdinsky, S. Oswald, P. Ranachowski, Z. Ranachowski, S. Kudela, Decomposition of silica binder during infiltration
of Saffil fiber preform with Mg and Mg-Li melts, Kovove Materialy - Metallic Materials 52 (2014) Nr. 4, S. 183-188.
168) P. Kumar, D.V.S. Muthu, L. Harnagea, S. Wurmehl, B. Buechner, A.K. Sood, Phonon anomalies, orbital-ordering and electronic
raman scattering in iron-pnictide Ca(Fe0.97Co0.03)2As2: Temperature-dependent Raman study, Journal of Physics: Condensed
Matter 26 (2014) Nr. 30, S. 305403/1-5.
169) S. Kumar, L. Harnagea, S. Wurmehl, B. Buechner, A.K. Sood, Signatures of superconducting and pseudogap phases in ultrafast
transient reflectivity of Ca (Fe0.927Co0.073) 2As2, epl 105 (2014) Nr. 4, S. 47004/1-6.
170) S. Kumar, E. Zallo, Y.H. Liao, P.Y. Lin, R. Trotta, P. Atkinson, J.D. Plumhof, F. Ding, B.D. Gerardot, S.J. Cheng, A. Rastelli,
O.G. Schmidt, Anomalous anticrossing of neutral exciton states in GaAs/AlGaAs quantum dots, Physical Review B 89 (2014) Nr. 11,
S. 115309/1-10.
171) J. Lach, A. Jeremies, D. Breite, B. Abel, B. Mahns, M. Knupfer, V. Matulis, O.A. Ivashkevich, B. Kersting, Encapsulation of the
4-mercaptobenzoate ligand by macrocyclic metal complexes: Conversion of a metallocavitand to a metalloligand, Inorganic
Chemistry 53 (2014), S. 10825-10834.
172) M.H. Lee, B.S. Kim, D.H. Kim, R.T. Ott, F. Sansoz, J. Eckert, Effect of geometrical constraint condition on the formation of
nanoscale twins in the Ni-based metallic glass composite, Philosophical Magazine Letters 94 (2014) Nr. 6, S. 351-360.
173) M.H. Lee, E.S. Park, R.T. Ott, B.S. Kim, J. Eckert, Evaluation of the relationship between the effective strain and the springback
behavior during the deformation of metallic glass ribbons, Applied Physics Letters 105 (2014) Nr. 6, S. 61906/1-3.
174) S.W. Lee, J.T. Kim, S.H. Hong, H.J. Park, J.-Y. Park, N.S. Lee, Y. Seo, J.Y. Suh, J. Eckert, D.H. Kim, J.M. Park, K.B. Kim,
Micro-to-nano-scale deformation mechanisms of a bimodal ultrafine eutectic composite, Scientific Reports 4 (2014), S. 6500/1-5.
175) A. Leifert, G. Mondin, S. Doerfler, S. Hampel, S. Kaskel, E. Hofmann, J. Zschetzsche, E. Pflug, G. Dietrich, M. Ruehl, S. Braun,
S. Schaedlich, Fabrication of nanoparticle-containing films and nano layers for alloying and joining, Advanced Engineering
Materials 16 (2014) Nr. 10, S. 1264-1269.
176) K. Li, C. Song, Q. Zhai, M. Stoica, J. Eckert, Microstructure evolution of gas-atomized Fe- 6.5 wt% Si droplets, Journal of Materials
Research 29 (2014) Nr. 4, S. 527-534.
177) G. Lin, D. Makarov, M. Melzer, W. Si, C. Yan, O.G. Schmidt, A highly flexible and compact magnetoresistive analytic device, Lab on a
Chip 14 (2014), S. 4050-4058.
178) S. Lindner, B. Mahns, U. Treske, O. Vilkov, F. Haidu, M. Fronk, D.R.T. Zahn, M. Knupfer, Epitaxial growth and electronic properties
of well ordered phthalocyanine heterojunctions MnPc/F16CoPc, The Journal of Chemical Physics 141 (2014), S. 94706/1-5.
179) A Liska, M. Rosenkranz, J. Klima, L. Dunsch, P. Lhotak, J. Ludvik, Formation and proof of stable bi-, tri- and tetraradical polyanions
during the electrochemical reduction of cone-polynitrocalix[4]arenes. An ESR-UV-vis spectroelectrochemical study, Electrochimica
Acta 140 (2014), S. 572-578.
180) X. Liu, W. Si, J. Zhang, X. Sun, J. Deng, S. Baunack, S. Oswald, L. Liu, C. Yan, O.G. Schmidt, Free-standing Fe2O3 nanomembranes
enabling ultra-long cycling life and high rate capability for Li-ion batteries, Scientific Reports 4 (2014), S. 7452/1-8.
181) L. Loeber, F.P. Schimansky, U. Kuehn, F. Pyczak, J. Eckert, Selective laser melting of a beta-solidifying TNM-B1 titanium aluminide
alloy, Journal of Materials Processing Technology 214 (2014) Nr. 9, S. 1852-1860.
182) M. Luckabauer, U. Kuehn, J. Eckert, W. Sprengel, Specific volume study of a bulk metallic glass far below its calorimetrically
determined glass transition temperature, Physical Review B 89 (2014) Nr. 17, S. 174113/1-6.
183) L. Ma, D.A. Gilbert, V. Neu, R. Schaefer, J.G. Zheng, X.Q. Yan, Z. Shi, K. Liu, S.M. Zhou, Magnetization reversal in perpendicularly
magnetized L10 FePd/FePt heterostructures, Journal of Applied Physics 116 (2014) Nr. 3, S. 33922/1-7.
184) P. Ma, K.G. Prashanth, S. Scudino, Y. Jia, H. Wang, C. Zou, Z. Wei, J. Eckert, Influence of annealing on mechanical properties of
Al- 20Si processed by selective laser melting, metals 4 (2014), S. 28-36.
185) P. Ma, C.M. Zou, H.W. Wang, S. Scudino, B.G. Fu, Z.J. Wei, U. Kuehn, J. Eckert, Effects of high pressure and SiC content on
microstructure and precipitation kinetics of Al–20Si alloy, Journal of Alloys and Compounds 586 (2014), S. 639-644.
186) P. Machata, P. Rapta, V. Lukes, K.R. Idzik, T. Licha, R. Beckert, L. Dunsch, Regioregular electrochromic polymers based on thienyl
derivatives of fluorescent pyrene monomers: Optical properties, spectroelectrochemistry and quantum chemical study,
Electrochimica Acta 122 (2014), S. 57-65.
187) A. Madani, S. Boettner, M.R. Jorgensen, O.G. Schmidt, Rolled-up TiO2 optical microcavities for telecom and visible photonics,
Optics Letters 39 (2014) Nr. 2, S. 189-192.
188) V. Magdanz, M. Guix, O.G. Schmidt, Tubular micromotors: from microjets to spermbots, Robotics and Biomimetics 1 (2014) Nr. 11,
S. 1-10.
189) V. Magdanz, O.G. Schmidt, Spermbots: Potential impact for drug delivery and assisted reproductive technologies (Editorial),
informa Healthcare (2014), S. 1125-1129.
190) V. Magdanz, G. Stoychev, L. Ionov, S. Sanchez, O.G. Schmidt, Stimuli-responsive microjets with reconfigurable shape,
Angewandte Chemie - International Edition 53 (2014) Nr. 10, S. 2673-2677.
191) B. Mahns, O. Kataeva, D. Islamov, S. Hampel, F. Steckel, C. Hess, M. Knupfer, B. Buechner, C. Himcinschi, T. Hahn, R. Renger,
J. Kortus, Crystal growth, structure, and transport properties of the charge-transfer salt picene/2,3,5,6-tetrafluoro-7,7,8,8- tetracyanoquinodimethane, Crystal Growth and Design 14 (2014), S. 1338-1346.
192) S. Makharza, O. Vittorio, G. Cirillo, S. Oswald, E. Hinde, M. Kavallaris, B. Buechner, M. Mertig, S. Hampel, Graphene oxide - Gelatin
nanohybrids as functional tools for enhanced carboplatin activity in neuroblastoma cells, Pharmaceutical Research online first
(2014).
193) L.A.B. Marcal, B.L.T. Rosa, G.A.M. Safar, R.O. Freitas, O.G. Schmidt, P.S.S. Guimaraes, C. Deneke, A. Malachias, Observation of
emission enhancement caused by symmetric carrier depletion in III-V nanomembrane heterostructures, ACS Photonics 1 (2014),
S. 863-870.
194) D. Marko, K.G. Prashanth, S. Scudino, Z. Wang, N. Ellendt, V. Uhlenwinkel, J. Eckert, Al-based metal matrix composites reinforced
with Fe49.9Co35.1Nb7.7B4.5Si2.8 glassy powder: Mechanical behavior under tensile loading, Journal of Alloys and Compounds 615
(2014), S. S382-S385.
195) T. Marr, J. Freudenberger, V. Maier, H.W. Hoeppel, M. Goeken, L. Schultz, The strengthening effect of phase boundaries in a severely
plastically deformed Ti-Al composite wire, metals 4 (2014), S. 37-54.
196) M.L. Martine, G. Parzych, F. Thoss, L. Giebeler, J. Eckert, Na-Sb-Sn ternary phase diagram at room temperature for potential anode
materials in sodium-ion batteries, Solid State Ionics 268 (2014), S. 261-264.
197) C.S. Martinez-Cisneros, S. Sanchez, W. Xi, O.G. Schmidt, Ultracompact three-dimensional tubular conductivity microsensors for
ionic and biosensing applications, Nano Letters 14 (2014), S. 2219-2224.
198) N. Mattern, Comment on - Thermal expansion measurements by X-ray scattering and breakdown of Ehrenfest’s relation in alloy
liquids - Appl. Phys. Lett. 104, 191907 (2014), Applied Physics Letters 105 (2014) Nr. 25, S. 256101/1-2.
199) N. Mattern, J.H. Han, K.G. Pradeep, K.C. Kim, E.M. Park, D.H. Kim, Y. Yokoyama, D. Raabe, J. Eckert, Structure of rapidly quenched
(Cu0.5Zr0.5)100xAgx alloys (x = 0–40 at.%), Journal of Alloys and Compounds 607 (2014), S. 285-290.
200) N. Mattern, Y. Yokoyama, A. Mizuno, J.H. Han, O. Fabrichnaya, T. Harada, S. Kohara, J. Eckert, Experimental and thermodynamic
assessment of the Nd-Zr system, CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 46 (2014), S. 103-107.
201) N. Mattern, Y. Yokoyama, A. Mizuno, J.H. Han, O. Fabrichnaya, T. Harada, S. Kohara, J. Eckert, Experimental and thermodynamic
assessment of the Nd-Ti system, CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 47 (2014), S. 136-143.
202) N. Mattern, Y. Yokoyama, A. Mizuno, J.H. Han, O. Fabrichnaya, H. Wendrock, T. Harada, S. Kohara, J. Eckert, Experimental and
thermodynamic assessment of the Ce-Zr system, CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 46 (2014),
S. 213-219.
203) E.M. Mazzer, C.S. Kiminami, P. Gargarella, R.D. Cava, L.A. Basilio, C. Bolfarini, W.J. Botta, J. Eckert, T. Gustmann, S. Pauly,
Atomization and selective laser melting of a Cu-Al-Ni-Mn shape memory alloy, Materials Science Forum 802 (2014), S. 343-348.
204) B. Meana-Esteban, A. Petr, C. Kvarnstroem, A. Ivaska, L. Dunsch, Poly(2-methoxynaphthalene): A spectroelectrochemical study
on a fused ring conducting polymer, Electrochimica Acta 115 (2014), S. 10-15.
205) R. Medda, A. Helth, P. Herre, D. Pohl, B. Rellinghaus, N. Perschmann, S. Neubauer, H. Kessler, S. Oswald, J. Eckert, J.P. Spatz,
A. Gebert, E.A. Cavalcanti-Adam, Investigation of early cell-surface interactions of human mesenchymal stem cells on nanopatterned
beta- type titanium niobium alloy surfaces, Interface Focus 4 (2014) Nr. 1, S. 20130046/1-11.
206) A. Meier, M. Weinberger, K. Pinkert, M. Oschatz, S. Paasch, L. Giebeler, H. Althues, E. Brunner, J. Eckert, S. Kaskel, Silicon
oxycarbide-derived carbons from a polyphenylsilsequioxane precursor for supercapacitor applications, Microporous and Mesoporous
Materials 188 (2014), S. 140-148.
207) T. Meissner, S.K. Goh, J. Haase, M. Richter, K. Koepernik, H. Eschrig, Nuclear magnetic resonance at up to 10.1 GPa pressure detects
an electronic topological transition in aluminum metal, Journal of Physics: Condensed Matter 26 (2014) Nr. 1, S. 15501/1-5.
208) M. Melzer, D. Karnaushenko, G. Lin, S. Baunack, D. Makarov, O.G. Schmidt, Direct transfer of magnetic sensor devices to elastomeric
supports for stretchable electronics, Advanced Materials online first (2014).
209) M. Melzer, J.I. Moench, D. Makarov, Y. Zabila, G.S.C. Bermudez, D. Karnaushenko, S. Baunack, F. Bahr, C. Yan, M. Kaltenbrunner,
O.G. Schmidt, Wearable magnetic field sensors for flexible electronics, Advanced Materials online first (2014).
210) R.G. Mendes, B. Koch, A. Bachmatiuk, A.A. El-Gendy, Y. Krupskaya, A. Springer, R. Klingeler, O. Schmidt, B. Buechner, S. Sanchez,
M.H. Ruemmeli, Synthesis and toxicity characterization of carbon coated iron oxide nanoparticles with highly defined size
distributions, Biochimica et Biophysica Acta 1840 (2014), S. 160-169.
211) D. Mikhailova, C.Y. Kuo, P. Reichel, A.A. Tsirlin, A. Efimenko, M. Rotter, M. Schmidt, Z. Hu, T.W. Pi, L.Y. Jang, Y.L. Soo, S. Oswald,
L.H. Tjeng, Structure, magnetism, and valence states of Cobalt and Platinum in quasi-one-dimensional oxides A3CoPtO6 with A = Ca,
Sr, The Journal of Physical Chemistry C 118 (2014), S. 5463-5469.
212) A. Mohan, B. Buechner, S. Wurmehl, C. Hess, Growth of single crystalline delafossite LaCuO2 by the travelling-solvent floating zone
method, Journal of Crystal Growth 402 (2014), S. 304-307.
213) A. Mohan, N. Sekhar Beesetty, N. Hlubek, R. Saint-Martin, A. Revcolevschi, B. Buechner, C. Hess, Bond disorder and spinon heat
transport in the S= 1/2 Heisenberg spin chain compound Sr 2 CuO 3: From clean to dirty limits, Physical Review B 89 (2014) Nr. 10,
S. 104302/1-.
214) M. Moore, R. Sueptitz, A. Gebert, L. Schultz, O. Gutfleisch, Impact of magnetization state on the corrosion of sintered Nd-Fe-B
magnets for e-motor applications, Materials and Corrosion 65 (2014) Nr. 9, S. 891-896.
215) F. Mueller, G. Doerfel, Zwischen Wissenschaft und Handwerk - Der Glasinstrumentenbauer Heinrich Geissler und seine Schule,
Physik-Journal 13 (2014) Nr. 5, S. 39-42.
216) N.K. Mukhopadhyay, F. Ali, S. Scudino, M. Samadi Khoshkhoo, M. Stoica, V.C. Srivastava, V. Uhlenwinkel, G. Vaughan,
C. Suryanarayana, J. Eckert, Inverse Hall-Petch like mechanical behaviour in nanophase AlCuFe quasicrystals: A new phenomenon,
Acta Physica Polonica A 126 (2014) Nr. 2, S. 543-548.
217) F.M. Muntyanu, A. Gilewski, K. Nenkov, K. Rogacki, A.J. Zaleski, G. Fuks, V. Chistol, Magnetic properties of bi-, tri- and multicrystals
of 3D topological insulator Bi1-x-Sbx ..., Physics Letters A 378 (2014) Nr. 16-17, S. 1213-1216.
218) Y.G. Naidyuk, O.E. Kvitnitskaya, S. Aswartham, G. Fuchs, K. Nenkov, S. Wurmehl, Exploring point-contact spectra of
Ba1-xNaxFe2As2 in the normal and superconducting states, Physical Review B 89 (2014) Nr. 10, S. 104512/1-9.
219) Y.G. Naidyuk, O.E. Kvitnitskaya, N.V. Gamayunova, L. Boeri, S. Aswartham, S. Wurmehl, B. Buechner, D.V. Efremov, G. Fuchs,
S.-L. andDrechsler, Single 20 meV boson mode in KFe2As2 detected by point-contact spectroscopy, Physical Review B 90 (2014)
Nr. 9, S. 94505/1-9.
220) E. Nazarova, K. Buchkov, S. Terzieva, K. Nenkov, A. Zahariev, D. Kovacheva, N. Balchev, G. Fuchs, The effect of Ag addition on the
superconducting properties of FeSe0.94 , Journal of Superconductivity and Novel Magnetism online first (2014).
221) R. Niemann, O. Heczko, L. Schultz, S. Faehler, Inapplicability of the Maxwell relation for the quantification of caloric effects in
anisotropic ferroic materials, International Journal of Refrigeration 37 (2014), S. 281-288.
222) R. Niemann, J. Kopecek, O. Heczko, J. Romberg, L. Schultz, S. Faehler, E. Vives, L. Manosa, A. Planes, Localizing sources of
acoustic emission during the martensitic transformation, Physical Review B 89 (2014) Nr. 21, S. 214118/1-11.
223) I.V. Okulov, M. Boenisch, U. Kuehn, W. Skrotzki, J. Eckert, Significant tensile ductility and toughness in an ultrafine-structured
Ti68.8Nb13.6Co6Cu5.1Al6.5 bi-modal alloy, Materials Science and Engineering A 615 (2014), S. 457-463.
224) I.V. Okulov, U. Kuehn, T. Marr, J. Freudenberger, L. Schultz, C.-G. Oertel, W. Skrotzki, J. Eckert, Deformation and fracture behavior
of composite structured Ti-Nb-Al-Co(-Ni) alloys, Applied Physics Letters 104 (2014) Nr. 7, S. 71905/1-4.
225) I.V. Okulov, U. Kuehn, T. Marr, J. Freudenberger, I.V. Soldatov, L. Schultz, C.-G. Oertel, W. Skrotzki, J. Eckert, Microstructure and
mechanical properties of new composite structured Ti–V–Al–Cu–Ni alloys for spring applications, Materials Science and Engineering
A 603 (2014), S. 76-83.
226) I.V. Okulov, U. Kuehn, J. Romberg, I.V. Soldatov, J. Freudenberger, L. Schultz, A. Eschke, C.-G. Oertel, W. Skrotzki, J. Eckert,
Mechanical behavior and tensile/compressive strength asymmetry of ultrafine structured Ti-Nb-Ni-Co-Al alloys with bi-modal grain
size distribution, Materials and Design 62 (2014), S. 14-20.
227) A. Omar, C.G.F. Blum, W. Loeser, B. Buechner, S. Wurmehl, Effect of annealing on spinodally decomposed Co2CrAl grown via floating
zone technique, Journal of Crystal Growth 401 (2014), S. 617-621.
228) M. Oschatz, L. Borchardt, K. Pinkert, S. Thieme, M.R. Lohe, C. Hoffmann, M. Benusch, F.M. Wisser, C. Ziegler, L. Giebeler,
M.H. Ruemmeli, J. Eckert, A. Eychmueller, S. Kaskel, Hierarchical carbide-derived carbon foams with advanced mesostructure
as a versatile electrochemical energy- storage material, Advanced Energy Materials 4 (2014) Nr. 2, S. 1300645/1-9.
229) S. Oswald, P.-F. Gostin, A. Helth, S. Abdi, L. Giebeler, H. Wendrock, M. Calin, J. Eckert, A. Gebert, XPS and AES sputter-depth
profiling at surfaces of biocompatible passivated Ti-based alloys: Concentration quantification considering chemical effects,
Surface and Interface Analysis 46 (2014), S. 683-688.
230) S. Oswald, U. Vogel, J. Eckert, ARXPS measurement simulation for improved data interpretation at complex Ta/Li-niobate interfaces,
Surface and Interface Analysis 46 (2014), S. 1094-1098.
231) J.M. Park, K.R. Lim, E.S. Park, S. Hong, K.H. Park, J. Eckert, D.H. Kim, Internal structural evolution and enhanced tensile plasticity
of Ti-based bulk metallic glass and composite via cold rolling, Journal of Alloys and Compounds 615 (2014) Nr. S1, S. S113-S117.
232) G. Parzych, D. Mikhailova, S. Oswald, C. Taeschner, M. Ritschel, A. Leonhardt, J. Eckert, H. Ehrenberg, Improved electrochemical
performance of Cu3B2O6-based conversion model electrodes by composite formation with different carbon additives, Journal of The
Electrochemical Society 161 (2014), S. A1224-A1230.
233) A.K. Patra, F. Fleischhauer, S. Oswald, L. Schultz, V. Neu, Coercivity mechanism in hard magnetic SmCo5/PrCo5 bilayers, Journal of
Physics D: Applied Physics 47 (2014), S. 215001/1-8.
234) R. Patra, S. Ghosh, E. Sheremet, M. Jha, R.D. Rodriguez, D. Lehmann, A.K. Ganguli, O.D. Gordan, H. Schmidt, S. Schulze,
D.R.T. Zahn, O.G. Schmidt, Enhanced field emission from cerium hexaboride coated multiwalled carbon nanotube composite films:
A potential material for next generation electron sources, Journal of Applied Physics 115 (2014), S. 94302/1-7.
235) R. Patra, S. Ghosh, E. Sheremet, M. Jha, R.D. Rodriguez, D. Lehmann, A.K. Ganguli, H. Schmidt, S. Schulze, M. Hietschold,
D.R.T. Zahn, O.G. Schmidt, Enhanced field emission from lanthanum hexaboride coated multiwalled carbon nanotubes:
Correlation with physical properties, Journal of Applied Physics 116 (2014), S. 164309/1-7.
236) S. Pauly, K. Kosiba, P. Gargarella, B. Escher, K.K. Song, G. Wang, U. Kuehn, J. Eckert, Microstructural evolution and mechanical
behaviour of metastable Cu-Zr-Co alloys, Journal of Material Science and Technologie 30 (2014) Nr. 6, S. 584-589.
237) O. Perevertov, R. Schaefer, Influence of applied tensile stress on the hysteresis curve and magnetic domain structure of grainoriented Fe-3%Si steel, Journal of Physics D: Applied Physics 47 (2014), S. 185001/1-10.
238) O. Perevertov, R. Schaefer, O. Stupakov, 3-D branching of magnetic domains on compressed Si-Fe steel with goss texture,
IEEE Transactions on Magnetics 50 (2014) Nr. 11, S. 2007804/1-4.
239) T. Pezeril, C. Klieber, V. Shalagatskyi, G. Vaudel, V. Temnov, O.G. Schmidt, D. Makarov, Femtosecond imaging of nonlinear
acoustics in gold, Optics Express (2014), S. 4590-4598.
240) M. Pfeiffer, K. Lindfors, H. Zhang, B. Fenk, F. Phillipp, P. Atkinson, A. Rastelli, O.G. Schmidt, H. Giessen, M. Lippitz,
Eleven nanometer alignment precision of a plasmonic nanoantenna with a self-assembled GaAs quantum dot, Nano Letters 14
(2014), S. 197-201.
241) P. Philipp, L. Bischoff, U. Treske, B. Schmidt, J. Fiedler, R. Huebner, F. Klein, A. Koitzsch, T. Muehl, The origin of conductivity in
ion-irradiated diamond-like carbon - Phase transformation and atomic ordering, Carbon 80 (2014), S. 677-690.
242) R. Pinedo, I. Ruiz de Larramendi, V.O. Khavrus, D. Jimenez de Aberasturi, J.I. Ruiz de Larramendi, M. Ritscheld, A. Leonhardt,
T. Rojo, Microstructural improvements of the gradient composite material Pr0.6Sr0.4Fe0.8Co0.2O3/ Ce0.8Sm0.2O1.9 by employing
vertically aligned carbon nanotubes, International Journal of Hydrogen Energy 39 (2014), S. 4074-4080.
243) K. Pinkert, M. Oschatz, L. Borchardt, M. Klose, M. Zier, W. Nickel, L. Giebeler, S. Oswald, S. Kaskel, J. Eckert, Role of surface
functional groups in ordered mesoporous carbide- derived carbon/ionic liquid electrolyte double-layer capacitor interfaces,
Applied Materials and Interfaces 6 (2014), S. 2922-2928.
244) W. Piyawit, W.Z. Xu, S.N. Mathaudhua, J. Freudenberger, J.M. Rigsbee, Y.T. Zhu, Nucleation and growth mechanism of Ag
precipitates in a CuAgZr alloy, Materials Science and Engineering A 610 (2014), S. 85-90.
245) A. Plotnikov, J. Pfeifer, S. Richter, H. Kipphardt, V. Hoffmann, Determination of major nonmetallic impurities in magnesium by
glow discharge mass spectrometry with a fast flow source using sintered and pressed powder samples, Analytical and Bioanalytical
Chemistry 406 (2014), S. 7463-7471.
246) D. Pohl, U. Wiesenhuetter, E. Mohn, L. Schultz, B. Rellinghaus, Near-surface strain in icosahedra of binary metallic alloys:
Segregational versus intrinsic effects, Nano Letters 14 (2014), S. 1776-1784.
247) G. Pollefeyt, S. Clerick, P. Vermeir, J. Feys, R. Huehne, P. Lommens, I. Van Driessche, Ink-jet printing of SrTiO3 buffer layers from
aqueous solutions, Superconductor Science and Technology 27 (2014) Nr. 9, S. 95007/1-9.
248) A.A. Popov, C. Kaestner, M. Krause, L. Dunsch, Carbon cage vibrations of M-at- C82 and M2-at- C2 n (M = La, Ce; 2n?=?72, 78, 80):
The role of the metal atoms, Fullerenes, Nanotubes and Carbon Nanostructures 22 (2014) Nr. 1-3, S. 202-214.
249) K.G. Prashanth, R. Damodaram, S. Scudino, Z. Wang, K. Prasad Rao, J. Eckert, Friction welding of Al-12Si parts produced by
selective laser melting, Materials and Design 57 (2014), S. 632-637.
250) K.G. Prashanth, B. Debalina, Z. Wang, P.F. Gostin, A. Gebert, M. Calin, U. Kuehn, M. Kamaraj, S. Scudino, J. Eckert, Tribological and
corrosion properties of Al-12Si produced by selective laser melting, Journal of Materials Research 29 (2014) Nr. 17, S. 2044-2054.
251) K.G. Prashanth, S. Scudino, H.J. Klauss, K.B. Surreddi, L. Loeber, Z. Wang, A.K. Chaubey, U. Kuehn, J. Eckert, Microstructure and
mechanical properties of Al-12Si produced by selective laser melting: Effect of heat treatment, Materials Science and Engineering A
590 (2014), S. 153-160.
252) N. Qureshi, P. Steffens, D. Lamago, Y. Sidis, O. Sobolev, R.A. Ewings, L. Harnagea, S. Wurmehl, B. Buechner, M. Braden,
Fine structure of the incommensurate antiferromagnetic fluctuations in single-crystalline LiFeAs studied by inelastic neutron
scattering, Physical Review B 90 (2014) Nr. 14, S. 144503/1-8.
253) A. Raduta, M. Nicoara, C. Locovei, M. Stoica, J. Eckert, About replacement of Nickel as amorphization element for fabrication of
ultra-rapidly solidified Ti-Zr alloys, Solid State Phenomena 216 (2014) Nr. 3, S. 3-10.
254) G.K. Rane, S. Menzel, T. Gemming, J. Eckert, Microstructure, electrical resistivity and stresses in sputter deposited W and Mo films
and the influence of the interface on bilayer properties, Thin Solid Films 571 (2014), S. 1-8.
255) L. Reichel, G. Giannopoulos, S. Kauffmann-Weiss, M. Hoffmann, D. Pohl, A. Edstroem, S. Oswald, D. Niarchos, J. Rusz, L. Schultz,
S. Faehler, Increased magnetocrystalline anisotropy in epitaxial Fe-Co-C thin films with spontaneous strain, Journal of Applied
Physics 116 (2014) Nr. 21, S. 213901/1-5.
256) A. Reifenberger, M. Hempel, P. Vogt, S. Aswartham, M. Abdel-Hafiez, V. Grinenko, S. Wurmehl, S.-L. Drechsler, A. Fleischmann,
C. Enss, R. Klingeler, Specific heat of K0.71Na0.29Fe2As2 at very low temperatures, Journal of Low Temperature Physics 175 (2014)
Nr. 5-6, S. 755-763.
257) J. Ren, C. Chen, G. Wang, W.-S. Cheung, B. Sun, N. Mattern, S. Siegmund, J. Eckert, Various sizes of sliding event bursts in the
plastic flow of metallic glasses based on a spatiotemporal dynamic model, Journal of Applied Physics 116 (2014), S. 33520/1-3.
258) L. Restrepo-Perez, L. Soler, C. Martinez-Cisneros, S. Sanchez, O.G. Schmidt, Biofunctionalized self-propelled micromotors as an
alternative on-chip concentrating system, Lab on a Chip 14 (2014), S. 2914-2917.
259) L. Restrepo-Perez, L. Soler, C.S. Martinez-Cisneros, S. Sanchez, O.G. Schmidt, Trapping self-propelled micromotors with
microfabricated chevron and heart-shaped chips, Lab on a Chip 14 (2014), S. 1515/1-5.
260) R.O. Rezaev, V.M. Fomin, O.G. Schmidt, Vortex dynamics controlled by pinning centers on Nb superconductor open microtubes,
Physica C 497 (2014), S. 1-5.
261) E.D.L. Rienks, M. Aerraelae, M. Lindroos, F. Roth, W. Tabis, G. Yu, M. Greven, J. Fink, High-energy anomaly in the Angle-Resolved
photoemission spectra of Nd2-xCexCuO4: Evidence for a matrix element effect, Physical Review Letters 113 (2014) Nr. 13,
S. 137001/1-5.
262) J. Ringel, K. Erdmann, S. Hampel, K. Kraemer, D. Maier, M. Arlt, D. Kunze, M.P. Wirth, S. Fuessel, Carbon nanofibers and carbon
nanotubes sensitize prostate and bladder cancer cells to platinum-based chemotherapeutics, Journal of Biomedical Nanotechnology
10 (2014) Nr. 3, S. 463-477.
263) S. Rittinghausen, A. Hackbarth1, O. Creutzenberg, H. Ernst, U. Heinrich, A. Leonhardt, D. Schaudien, The carcinogenic effect of
various multi-walled carbon nanotubes (MWCNTs) after intraperitoneal injection in rats, Particle and Fibre Toxicology 11 (2014),
S. 59/1-18.
264) P. Robaschik, P.F. Siles, D. Buelz, P. Richter, M. Monecke, M. Fronk, S. Klyatskaya, D. Grimm, O.G. Schmidt, M. Ruben, D.R.T. Zahn,
G. Salvan, Optical properties and electrical transport of thin films of terbium(III) bis(phthalocyanine) on cobalt, Beilstein Journal
of Nanotechnology 5 (2014), S. 2070-2078.
265) T. Roch, F. Klein, K. Guenther, A. Roch, T. Muehl, A. Lasagni, Laser interference induced nano-crystallized surface swellings of
amorphous carbon for advanced micro tribology, Materials Research Express 1 (2014), S. 35042/1-14.
266) F. Roth, A. Koenig, J. Fink, B. Buechner, M. Knupfer, Electron energy-loss spectroscopy: A versatile tool for the investigations of
plasmonic excitations, Journal of Electron Spectroscopy and Related Phenomena 195 (2014), S. 85-95.
267) K. Sakaushi, E. Hosono, G. Nickerl, H. Zhou, S. Kaskel, J. Eckert, Bipolar porous polymeric frameworks for low-cost, high-power,
long-life all-organic energy storage devices, Journal of Power Sources 245 (2014), S. 553-556.
268) F. Sannicolo, S. Arnaboldi, T. Benincori, V. Bonometti, R. Cirilli, L. Dunsch, W. Kutner, G. Longhi, P.R. Mussini, M. Panigati,
M. Pierini, S. Rizzo, Potential-driven chirality manifestations and impressive enantioselectivity by inherently chiral electroactive
organic films, Angewandte Chemie - International Edition 53 (2014), S. 2623-2627.
269) A.E. Sarapulova, B. Bazarov, T. Namsaraeva, S. Dorzhieva, J. Bazarova, V. Grossman, A.A. Bush, I. Antonyshyn, M. Schmidt, A.M.T.
Bell, M. Knapp, H. Ehrenberg, J. Eckert, D. Mikhailova, Possible piezoelectric materials CsMZr0.5(MoO4)3 (M = Al, Sc, V, Cr, Fe, Ga,
In) and CsCrTi0.5(MoO4)3: Structure and physical properties, The Journal of Physical Chemistry C 118 (2014), S. 1763-1773.
270) S. Scheinert, G. Paasch, Influence of the carrier density in disordered organics with Gaussian density of states on organic field-effect
transistors, Journal of Applied Physics 115 (2014) Nr. 4, S. 44507/1-8.
271) T. Schied, H. Ehrenberg, J. Eckert, S. Oswald, M. Hoffmann, F. Scheiba, An O2 transport study in porous materials within
the Li-O2 -system, Journal of Power Sources 269 (2014), S. 825-833.
272) R. Schlegel, T. Haenke, D. Baumann, M. Kaiser, P.K. Nag, R. Voigtlaender, D. Lindackers, B. Buechner, C. Hess, Design and
properties of a cryogenic dip-stick scanning tunneling microscope with capacitive coarse approach control, Review of Scientific
Instruments 85 (2014) Nr. 1, S. 13706/1-9.
273) S. Schmitz, H.-G. Lindenkreuz, W. Loeser, B. Buechner, Liquid phase separation, solidification and phase transformations of
Gd-Ti andGd-Ti-Al-Cu alloys, CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 44 (2014), S. 21-25.
274) S. Schneider, A. Surrey, D. Pohl, L. Schultz, B. Rellinghaus, Atomic surface diffusion on Pt nanoparticles quantified by highresolution transmission electron microscopy, Micron 63 (2014), S. 52-56.
275) R. Schoenfelder, F. Aviles, M. Knupfer, J.A. Azamar-Barrios, P.I. Gonzalez-Chi, M.H. Ruemmeli, Influence of architecture on the
Raman spectra of acid-treated carbon nanostructures, Journal of Experimental Nanoscience 9 (2014) Nr. 9, S. 931-941.
276) H. Shakur Shahabi, S. Scudino, U. Kuehn, J. Eckert, Metallic glass-steel composite with improved compressive plasticity,
Materials and Design 59 (2014), S. 241-245.
277) R. Sharma, C.C. Bof Bufon, D. Grimm, R. Sommer, A. Wollatz, J. Schadewald, D.J. Thurmer, P.F. Siles, M. Bauer, O.G. Schmidt,
Large-area rolled-up nanomembrane capacitor arrays for electrostatic energy storage, Advanced Energy Materials 4 (2014) Nr. 9,
S. 1301631/1-6.
278) W. Si, I. Moench, C. Yan, J. Deng, S. Li, G. Lin, L. Han, Y. Mei, O.G. Schmidt, A single rolled-up Si tube battery for the study of
electrochemical kinetics, electrical conductivity, and structural integrity, Advanced Materials 26 (2014), S. 7973-7978.
279) W. Si, X. Sun, X. Liu, L. Xi, Y. Jia, C. Yan, O.G. Schmidt, High areal capacity, micrometer-scale amorphous Si film anode based on
nanostructured Cu foil for Li-ion batteries, Journal of Power Sources 267 (2014), S. 629-634.
280) M. Sieger, J. Haenisch, K. Iida, U. Gaitzsch, C. Rodig, L. Schultz, B. Holzapfel, R. Huehne, Pulsed laser deposition of thick
BaHfO3 doped YBa2Cu307-delta films on highly alloyed textured Ni-W tapes, Journal of Physics: Conference Series 507 (2014),
S. 22032/1-5.
281) B.W. Sigusch, S. Kranz, S. Klein, A. Voelpel, S. Harazim, S. Sanchez, D.C. Watts, K.D. Jandt, O.G. Schmidt, A. Guellmar,
Colonization of Enterococcus faecalis in a newSiO/SiO2-microtube in vitro model system as afunction of tubule diameter,
Dental Materials 30 (2014), S. 661-668.
282) P.F. Siles, C.C. Bof Bufon, D. Grimm, A.R. Jalil, C. Mende, F. Lungwitz, G. Salvan, D.R.T. Zahn, H. Lang, O.G. Schmidt,
Morphology and local transport characteristics of metalloporphyrin thin films, Organic Electronics 15 (2014) Nr. 7, S. 1432-1439.
283) J. Simmchen, V. Magdanz, S. Sanchez, S. Chokmaviroj, D. Ruiz-Molina, A. Baeza, O.G. Schmidt, Effect of surfactants on the
performance of tubular and spherical micromotors - A comparative study, RSC Advances 4 (2014), S. 20334-20340.
284) W. Skrotzki, A. Eschke, J. Romberg, J. Scharnweber, T. Marr, R. Petters, I. Okulov, C.-G. Oertel, J. Freudenberger, U. Kuehn,
L. Schultz, J. Eckert, Processing of high strength light-weight metallic composites, Advanced Engineering Materials 16 (2014)
Nr. 10, S. 1208-1216.
285) E. Smirnova, S. Smirnov, A. Sotnikov, M. Shevelko, H. Schmidt, M. Weihnacht, High temperature acoustic anomalies in
PMN-PSN solid solution, Ferroelectrics 469 (2014) Nr. 1, S. 67-72.
286) E. Smirnova, A. Sotnikov, S. Ktitorov, N. Zaitseva, H. Schmidt, M. Weihnacht, Acoustic evidence of distinctive temperatures in
relaxor-multiferroics, Journal of Applied Physics 115 (2014), S. 54101/1-7.
287) E.P. Smirnova, A.V. Sotnikov, N.V. Zaitseva, H. Schmidt, M. Weihnacht, Evolution of phase transitions in SrTiO3-BiFeO3 solid
solutions, Physics of the Solid State 56 (2014) Nr. 5, S. 996-1001.
288) K. Snyder, B. Raguz, W. Hoffbauer, R. Glaum, H. Ehrenberg, M. Herklotz, Lithium Copper (I) orthophosphates Li3-xCuxPO4:
Synthesis, crystal structures, and electrochemical properties, Zeitschrift fuer anorganische und allgemeine Chemie 640 (2014)
Nr. 5, S. 944-951.
289) A. Sobolkina, V. Mechtcherine, C. Bellmann, V. Khavrus, S. Oswald, S. Hampel, A. Leonhardt, Surface properties of CNTs and their
interaction with silica, Journal of Colloid and Interface Science 413 (2014), S. 43-53.
290) I.V. Soldatov, N. Panarina, C. Hess, L. Schultz, R. Schaefer, Thermoelectric effects and magnetic anisotropy of Ga1-xMnxAs thin
films, Physical Review B 90 (2014) Nr. 10, S. 104423/1-9.
291) E. Song, W. Si, R. Cao, P. Feng, I. Moench, G. Huang, Z. Di, O.G. Schmidt, Y. Mei, Schottky contact on ultra-thin silicon nanomembranes under light illumination, Nanotechnology 25 (2014) Nr. 48, S. 485201/1-7.
292) F. Steckel, S. Rodan, R. Hermann, C.G.F. Blum, S. Wurmehl, B. Buechner, C. Hess, Spin density wave order and fluctuations in
Mn3Si : A transport study, Physical Review B 90 (2014) Nr. 13, S. 134411/1-7.
293) E. Stilp, A. Suter, T. Prokscha, Z. Salman, E. Morenzoni, H. Keller, P. Pahlke, R. Huehne, C. Bernhard, R. Liang, W.N. Hardy,
D.A. Bonn, J.C. Baglo, R.F. Kiefl, Controlling the near-surface superfluid density in underdoped YBa2Cu3O61x by photo-illumination,
Scientific Reports 4 (2014), S. 6250/1-6.
294) M. Stoica, S. Scudino, J. Bednarcik, I. Kaban, J. Eckert, FeCoSiBNbCu bulk metallic glass with large compressive deformability
studied by time-resolved synchrotron X-ray diffraction, Journal of Applied Physics 115 (2014) Nr. 5, S. 53520/1-9.
295) O.A. Stonkus, L.S. Kibis, O.Y. Podyacheva, E.M. Slavinskaya, V.I. Zaikovskii, A.H. Hassan, S. Hampel, A. Leonhardt, Z.R. Ismagilov,
A.S. Noskov, A.I. Boronin, Palladium nanoparticles supported on nitrogen-doped carbon nanofibers: Synthesis, microstructure,
catalytic properties, and self-sustained oscillation phenomena in carbon monoxide oxidation, ChemCatChem 6 (2014) Nr. 7,
S. 2115-2128.
296) R. Streubel, L. Han, F. Kronast, A.A. Uenal, O.G. Schmidt, D. Makarov, Imaging of buried 3D magnetic rolled-up nanomembranes, Nano Letters 14 (2014), S. 3981-3986.
297) R. Streubel, J. Lee, D. Makarov, M.-Y. Im, D. Karnaushenko, L. Han, R. Schaefer, P. Fischer, S.-K. Kim, O.G. Schmidt, Magnetic
microstructure of rolled-up single-layer ferromagnetic nanomembranes, Advanced Materials 26 (2014), S. 316-323.
298) V. Stroganov, S. Zakharchenko, E. Sperling, A.K. Meyer, O.G. Schmidt, L. Ionov, Biodegradable self-folding polymer films with
controlled thermo-triggered folding, Advanced Functional Materials 24 (2014), S. 4357-4363.
299) R. Sueptitz, K. Tschulik, M. Uhlemann, J. Eckert, A. Gebert, Retarding the corrosion of iron by inhomogeneous magnetic fields,
Materials and Corrosion 65 (2014) Nr. 8, S. 803-808.
300) X. Sun, W. Si, X. Liu, J. Deng, L. Xi, L. Liu, C. Yan, O.G. Schmidt, Multifunctional Ni/NiO hybrid nanomembranes as anode materials
for high-rate Li-ion batteries, Nano Energy 9 (2014), S. 168-175.
301) X. Sun, C. Yan, Y. Chen, W. Si, J. Deng, S. Oswald, L. Liu, O.G. Schmidt, Three-dimensionally “Curved” NiO nanomembranes as
ultrahigh rate capability anodes for Li-Ion batteries with long cycle lifetimes, Advanced Energy Materials 4 (2014) Nr. 4,
S. 1300912/1-6.
302) A. Svalov, L. Lokamani, R. Schaefer, V. Vaskovskiy, G. Kurlyandskaya, Magnetization processes and magnetic domain structure
in weakly coupled GdCo/Si/Co trilayers, Journal of Alloys and Compounds 615 (2014), S. S366-S370.
303) A.L. Svitova, K.B. Ghiassi, C. Schlesier, K. Junghans, Y. Zhang, M.M. Olmstead, A.L. Balch, L. Dunsch, A.A. Popov, Endohedral
fullerene with m3-carbido ligand and titanium-carbon double bond stabilized inside a carbon cage, nature communications 5
(2014), S. 3568/1-8.
304) A.L. Svitova, Y. Krupskaya, N. Samoylova, R. Kraus, J. Geck, L. Dunsch, A.A. Popov, Magnetic moments and exchange coupling
in nitride clusterfullerenes GdxSc3–xN-at- C80 (x = 1–3), Dalton Transactions 43 (2014), S. 7387-7390.
305) A.H. Taghvaei, H.S. Shahabi, J. Bednarcik, J. Eckert, Fabrication and characterization of Co40Fe22Ta8-xYxB30 (x=0, 2.5, 4, 6,
and 8) metallic glasses with high thermal stability and good soft magnetic properties, Journal of Applied Physics 116 (2014),
S. 184904/1-5.
306) A.H. Taghvaei, M. Stoica, J. Bednarcik, I. Kaban, H.S. Shahabi, M.S. Khoshkhoo, K. Janghorban, J. Eckert, Influence of ball milling
on atomic structure and magnetic properties of Co40Fe22Ta8B30 glassy alloy, Materials Characterization 92 (2014), S. 96-105.
307) A.H. Taghvaei, M. Stoica, I. Kaban, J. Bednarcik, J. Eckert, Thermal and soft magnetic properties of Co40Fe22Ta8B30 glassy
particles: In-situ X-ray diffraction and magnetometry studies, Journal of Applied Physics 116 (2014), S. 54904/1-8.
308) A.H. Taghvaei, M. Stoica, K. Song, K. Janghorban, J. Eckert, Crystallization kinetics of Co40Fe22Ta8B30 glassy alloy with high
thermal stability and soft magnetic properties, Journal of Alloys and Compounds 605 (2014), S. 199-207.
309) J. Tan, G. Wang, Z.Y. Liu, J. Bednarcik, Y.L. Gao, Q.J. Zhai, N. Mattern, J. Eckert, Correlation between atomic structure evolution
and strength in a bulk metallic glass at cryogenic temperature, Scientific Reports 4 (2014), S. 3897/1-7.
310) M. Taut, K. Koepernik, M. Richter, Electronic structure of stacking faults in rhombohedral graphite, Physical Review B 90 (2014)
Nr. 8, S. 85312/1-8.
311) I. Tereshina, J. Cwik, E. Tereshina, G. Politova, G. Burkhanov, V. Chzhan, A. Ilyushin, M. Miller, A. Zaleski, K. Nenkov, L. Schultz,
Multifunctional phenomena in Rare-Earth intermetallic compounds with a laves phase structure: Giant magnetostriction and
magnetocaloric effect, IEEE Transactions on Magnetics 50 (2014) Nr. 11, S. 2504604/1-4.
312) A. Teresiak, M. Uhlemann, J. Thomas, J. Eckert, A. Gebert, Influence of Co and Pd on the formation of nanostructured LaMg2Ni
and its hydrogen reactivity, Journal of Alloys and Compounds 582 (2014), S. 647-658.
313) F. Thoss, L. Giebeler, K. Weisser, J. Feller, J. Eckert, Preparation and cycling performance of Iron or Iron Oxide containing
amorphous Al-Li alloys as electrodes, Inorganics 2 (2014), S. 674-682.
314) U. Treske, N. Heming, M. Knupfer, B. Buechner, A. Koitzsch, E. Di Gennaro, U. Scotti di Uccio, F. Miletto Granozio, S. Krause,
Observation of strontium segregation in LaAlO3/SrTiO3 and NdGaO3/SrTiO3 oxide heterostructures by X-ray photoemission
spectroscopy, APL Materials 2 (2014), S. 12108/1-8.
315) U. Treske, M.S. Khoshkhoo, F. Roth, M. Knupfer, E.D. Bauer, J.L. Sarrao, B. Buechner, A. Koitzsch, X-ray photoemission study of
CeTIn5 (T = Co, Rh, Ir), Journal of Physics: Condensed Matter 26 (2014), S. 205601/1-5.
316) J. Trommer, S. Boettner, S. Li, S. Kiravittaya, M.R. Jorgensen, O.G. Schmidt, Observation of higher order radial modes in atomic
layer deposition reinforced rolled-up microtube ring resonators, Optics Letters 39 (2014) Nr. 21, S. 6335-6338.
317) S. Trommler, J. Haenisch, K. Iida, F. Kurth, L. Schultz, B. Holzapfel, R. Huehne, Investigation of the strain-sensitive
superconducting transition of BaFe1.8Co0.2As2 thin films utilizing piezoelectric substrates, Journal of Physics: Conference Series
507 (2014) Nr. 1, S. 12049/1-5.
318) R. Trotta, J.S. Wildmann, E. Zallo, O.G. Schmidt, A. Rastelli, Highly entangled photons from hybrid piezoelectric-semiconductor
quantum dot devices, Nano Letters 14 (2014) Nr. 6, S. 3439-3444.
319) H. Turnow, H. Wendrock, S. Menzel, T. Gemming, J. Eckert, Synthesis and characterization of amorphous Ni-Zr thin films,
Thin Solid Films 561 (2014), S. 48-52.
320) A. Undisz, R. Hanke, K.E. Freiberg, V. Hoffmann, M. Rettenmayr, The effect of heating rate on the surface chemistry of NiTi,
Acta Biomaterialia 10 (2014), S. 4919-4923.
321) V. Velasco, D. Pohl, A. Surrey, A. Bonatto-Minella, A. Hernando, P. Crespo, B. Rellinghaus, On the stability of AuFe alloy
nanoparticles, Nanotechnology 25 (2014) Nr. 21, S. 215703/1-8.
322) C. Vervacke, C.C. Bof Bufon, D.J. Thurmer, O.G. Schmidt, Three-dimensional chemical sensors based on rolled-up hybrid
nanomembranes, RSC Advances 4 (2014), S. 9723-9729.
323) S. Vock, C. Hengst, M. Wolf, K. Tschulik, M. Uhlemann, Z. Sasvari, D. Makarov, O.G. Schmidt, L. Schultz, V. Neu, Magnetic vortex
observation in FeCo nanowires by quantitative magnetic force microscopy, Applied Physics Letters 105 (2014), S. 172409/1-5.
324) U. Vogel, T. Gemming, J. Eckert, S. Oswald, Analysis of surface pre-treatment for SAW substrate material (LiNbO3) and deposited
thin films of Ta/Ti using ARXPS, Surface and Interface Analysis 46 (2014), S. 1033-1038.
325) H. Wadati, J. Geck, E. Schierle, R. Sutarto, F. He, D.G. Hawthorn, M. Nakamura, M. Kawasaki, Y. Tokura, G.A. Sawatzky, Revealing
orbital and magnetic phase transitions in Pr0:5Ca0:5MnO3 epitaxial thin films by resonant soft x-ray scattering, New Journal of
Physics 16 (2014) Nr. 3, S. 33006/1-13.
326) G. Wang, S. Pauly, S. Gorantla, N. Mattern, J. Eckert, Plastic flow of a Cu50Zr45Ti5 bulk metallic glass composite,
Journal of Material Science and Technologie 30 (2014) Nr. 6, S. 609-615.
327) K. Wang, A. Maljuk, C.G.F. Blum, T. Kolb, C. Jaehne, C. Neef, H.-J. Grafe, L. Giebeler, H. Wadepohl, H.-P. Meyer, S. Wurmehl,
R. Klingeler, Growth, characterization, and magnetic properties of a Li(Mn,Ni)PO4 single crystal, Journal of Crystal Growth 386
(2014) Nr. 16, S. 16-21.
328) Z. Wang, P. Li, Y. Chen, J. He, W. Zhang, O.G. Schmidt, Y. Li, Pure thiophene-sulfur doped reduced graphene oxide: synthesis,
structure, and electrical properties, Nanoscale 6 (2014), S. 7281-7287.
329) Z. Wang, K.G. Prashanth, S. Scudino, A.K. Chaubey, D.J. Sordelet, W.W. Zhang, Y.Y. Li, J. Eckert, Tensile properties of Al matrix
composites reinforced with in situ devitrified Al84Gd6Ni7Co3 glassy particles, Journal of Alloys and Compounds 586 (2014)
Nr. Suppl. 1, S. S419-S422.
330) Z. Wang, K.G. Prashanth, S. Scudino, J. He, W.W. Zhang, Y.Y. Li, M. Stoica, G. Vaughan, D.J. Sordelet, J. Eckert, Effect of ball
milling on structure and thermal stability of Al84Gd6Ni7Co3 glassy powders, Intermetallics 46 (2014), S. 97-102.
331) Z. Wang, J. Tan, S. Scudino, B.A. Sun, R.T. Qu, J. He, K.G. Prashanth, W.W. Zhang, Y.Y. Li, J. Eckert, Mechanical behavior of
Al-based matrix composites reinforced with Mg58Cu28.5Gd11Ag2.5 metallic glasses, Advanced Powder Technology 25 (2014) Nr. 2,
S. 635-639.
332) Z. Wang, J. Tan, B.A. Sun, S. Scudino, K.G. Prashanth, W.W. Zhang, Y.Y. Li, J. Eckert, Fabrication and mechanical properties of
Al-based metal matrix composites reinforced with Mg65Cu20Zn5Y10 metallic glass particles, Materials Science and Engineering A
600 (2014), S. 53-58.
333) Z. Weiss, E.B.M. Steers, J.C. Pickering, V. Hoffmann, S. Mushtaq, Excitation of higher levels of singly charged copper ions in argon
and neon glow discharges, Journal of Analytical Atomic Spectrometry 29 (2014) Nr. 12, S. 2256-2261.
334) R. Westerstroem, J. Dreiser, C. Piamonteze, M. Muntwiler, S. Weyeneth, K. Kraemer, S.-X. Liu, S. Decurtins, A. Popov, S. Yang,
L. Dunsch, T. Greber, Tunneling, remanence, and frustration in dysprosium-based endohedral single-molecule magnets, Physical
Review B 89 (2014) Nr. 6, S. 60406(R)/ 1-4.
335) G. Wittenburg, G. Lauer, S. Oswald, D. Labudde, C.M. Franz, Nanoscale topographic changes on sterilized glass surfaces affect cell
adhesion and spreading, Journal of Biomedical Materials Research Part A 102 A (2014), S. 2755-2766.
336) C. Wolf-Brandstetter, S. Oswald, S. Bierbaum, H.-P. Wiesmann, D. Scharnweber, Influence of pulse ratio on codeposition of copper
species with calcium phosphate coatings on titanium by means of electrochemically assisted deposition, Journal of Biomedical
Materials Research Part B: Applied Biomaterials 102 B (2014) Nr. 1, S. 160-172.
337) T.G. Woodcock, F. Bittner, T. Mix, K.-H. Mueller, S. Sawatzki, O. Gutfleisch, On the reversible and fully repeatable increase in
coercive field of sintered Nd-Fe-B magnets following post sinter annealing, Journal of Magnetism and Magnetic Materials 360
(2014), S. 157-164.
338) T.G. Woodcock, Q.M. Ramasse, G. Hrkac, T. Shoji, M. Yano, A. Kato, O. Gutfleisch, Atomic-scale features of phase boundaries in
hot deformed Nd-Fe-Co-B-Ga magnets infiltrated with a Nd-Cu eutectic liquid, Acta Materialia 77 (2014), S. 111-124.
339) S. Wurmehl, J.T. Kohlhepp, NMR spectroscopy on Heusler thin films - A review, SPIN 4 (2014) Nr. 4, S. 1440019/1-8.
340) W. Xi, C.K. Schmidt, S. Sanchez, D.H. Gracias, R.E. Carazo-Salas, S.P. Jackson, O.G. Schmidt, Rolled-up functionalized
nanomembranes as three-dimensional cavities for single cell studies, Nano Letters 14 (2014), S. 4197-4204.
341) Y.-K. Xu, Y.-N. Chen, Y.-J. Guo, L. Liu, J. Zhang, W. Loeser, Experimental parameters during optical floating zone crystal growth
of rare earth silicides, Rare Metals 33 (2014) Nr. 3, S. 343-347.
342) Y.-K. Xu, W. Loeser, Y.-J. Guo, X.-B. Zhao, L. Liu, Crystal growth of Gd2PdSi3 intermetallic compound, Transactions of Nonferrous
Matals Society of China 24 (2014), S. 115-119.
343) D.G. Yakhvarov, A. Petr, V. Kataev, B. Buechner, S. Gomez-Ruiz, E. Hey-Hawkins, S.V. Kvashennikova, Y.S. Ganushevich,
V.I. Morozov, O.G. Sinyashin, Synthesis, structure and electrochemical properties of the organonickel complex [NiBr(Mes)(phen)]
(Mes ¼ 2,4,6- trimethylphenyl, phen ¼ 1,10-phenanthroline), Journal of Organometallic Chemistry 750 (2014), S. 59-64.
344) L.X. Yang, G. Rohde, T. Rohwer, A. Stange, K. Hanff, C. Sohrt, L. Rettig, R. Cortes, F. Chen, D.L. Feng, T. Wolf, B. Kamble, I. Eremin,
T. Popmintchev, M.M. Murnane, H.C. Kapteyn, L. Kipp, J. Fink, M. Bauer, U. Bovensiepen, K. Rossnagel, Ultrafast modulation of
the chemical potential in BaFe2As2 by coherent phonons, Physical Review Letters 112 (2014) Nr. 20, S. 207001/1-6.
345) Y. Yerin, S.-L. Drechsler, G. Fuchs, Ginzburg-Landau analysis of the critical temperature and the upper critical field for three-band
superconductors, Journal of Low Temperature Physics 173 (2014), S. 247-263.
346) T. You, N. Du, S. Slesazeck, T. Mikolajick, G. Li, D. Buerger, I. Skorupa, H. Stoecker, B. Abendroth, A. Beyer, K. Volz, O.G. Schmidt,
H. Schmidt, Bipolar electric-field enhanced trapping and detrapping of mobile donors in BiFeO3 memristors, ACS Applied Materials
and Interfaces 6 (2014), S. 19758-19765.
347) T. You, Y. Shuai, W. Luo, N. Du, D. Buerger, I. Skorupa, R. Huebner, S. Henker, C. Mayr, R. Schueffny, T. Mikolajick, O.G. Schmidt,
H. Schmidt, Exploiting memristive BiFeO3 bilayer structures for compact sequential logics, Advanced Functional Materials 24 (2014),
S. 3357-3365.
348) E. Zallo, R. Trotta, V. Krapek, Y.H. Huo, P. Atkinson, F. Ding, T. Sikola, A. Rastelli, O.G. Schmidt, Strain-induced active tuning of the
coherent tunneling in quantum dot molecules, Physical Review B 89 (2014), S. 241303(R)/1-5.
349) F. Zeng, Y. Kuang, N. Zhang, Z. Huang, Y. Pan, Z. Hou, H. Zhou, C. Yan, O.G. Schmidt, Multilayer super-short carbon nanotube/
reduced graphene oxide architecture for enhanced supercapacitor properties, Journal of Power Sources 247 (2014), S. 396-401.
350) L. Zhang, J. Deng, L. Liu, W. Si, S. Oswald, L. Xi, M. Kundu, G. Ma, T. Gemming, S. Baunack, F. Ding, C. Yan, O.G. Schmidt,
Hierarchically designed SiOx/ SiOy bilayer nanomembranes as stable anodes for Lithium ion batteries, Advanced Materials 26 (2014),
S. 4527-4532.
351) Y. Zhang, A.A. Popov, L. Dunsch, Endohedral metal or a fullerene cage based oxidation? Redox duality of nitride clusterfullerenes
CexM3-xN@C78–88 (x = 1, 2; M = Sc and Y) dictated by the encaged metals and the carbon cage size, Nanoscale 6 (2014),
S. 1038-1048.
352) J. Zhao, Q. Deng, S.M. Avdoshenkoe, L. Fu, J. Eckert, M.H. Ruemmeli, Direct in situ observations of single Fe atom catalytic
processes and anomalous diffusion at graphene edges, in: PNAS, 111, 15641-15646 (2014).
353) J. Zhao, Q. Deng, A. Bachmatiuk, G. Sandeep, A. Popov, J. Eckert, M.H. Ruemmeli, Free-standing single-atom-thick iron
membranes suspended in graphene pores, Science 343 (2014), S. 1228-1232.
354) J. Zhao, M. Shaygan, J. Eckert, M. Meyyappan, M.H. Ruemmeli, A growth mechanism for free-standing vertical Graphene,
Nano Letters 14 (2014), S. 3064-3071.
355) L.-F. Zhu, M. Friak, A. Udyansky, D. Ma, A. Schlieter, U. Kuehn, J. Eckert, J. Neugebauer, Ab initio based study of finite-temperature
structural, elastic and thermodynamic properties of FeTi, Intermetallics 45 (2014), S. 11-17.
356) K. Zhuravleva, M. Boenisch, S. Scudino, M. Calin, L. Schultz, J. Eckert, A. Gebert, Phase transformations in ball-milled Ti-40Nb
and Ti-45Nb powders upon quenching from the beta—phase region, Powder Technology 253 (2014), S. 166-171.
357) K. Zhuravleva, R. Mueller, L. Schultz, J. Eckert, A. Gebert, M. Bobeth, G. Cuniberti, Determination of the Young’s modulus of
porous beta- type Ti–40Nb by finite element analysis, Materials and Design 64 (2014), S. 1-8.
358) M. Zier, F. Scheiba, S. Oswald, J. Thomas, D. Goers, T. Scherer, M. Klose, H. Ehrenberg, J. Eckert, Lithium dendrite and solid
electrolyte interphase investigation using OsO4, Journal of Power Sources 266 (2014), S. 198-207.
359) V. Zolyomi, H. Peterlik, J. Bernardi, M. Bokor, I. Laszlo, J. Koltai, J. Kuerti, M. Knupfer, H. Kuzmany, T. Pichler, F. Simon,
Toward synthesis and characterization of unconventional C66 and C68 Fullerenes inside carbon nanotubes, The Journal of Physical
Chemistry C 118 (2014), S. 30260-30268.
360) K. Zuzek Rozman, F. Rhein, U. Wolff, V. Neu, Single-vortex magnetization distribution and its reversal behaviour in Co-Pt nanotubes,
Acta Materialia 81 (2014), S. 469-475.
Contributions to Conference proceedings and monographs
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J. Acker, J. Ducke, A. Rietig, T. Mueller, S. Eisert, B. Reichenbach, W. Loeser, Segregation, grain boundary milling, and chemical
leaching for the refinement of metallurgical grade silicon for photovoltaic application, in: Silicon for the Chemical and Solar
Industry XII, Eds.: H.A. Øye, H. Brekken, H.M. Rong, M. Tangstad, H. Tveit, The Norwegian University of Science and Technology,
Trondheim, Norway,177-188 (2014).
S.V. Biryukov, H. Schmidt, A. Sotnikov, M. Weihnacht, S. Sakharov, O. Buzanov, CTGS material parameters obtained by versatile SAW
measurements, IEEE International Ultrasonics Symposium, in: Proceedings, 882-885 (2014).
F. Boerrnert, T. Riedel, H. Mueller, M. Linck, B. Buechner, H. Lichte, In-situ (S)TEM redesigned: Concept and electron-holographic
performance, 18th International Microscopy Congress, (2014), in: Proceedings, IT-7-O-1894 (2014).
R. Bruenig, A. Winkler, S. Wege, H. Schmidt, SAW technology for microfluidics and considerations about efficiency,
4th European Conference on Microfluidics, Limerick/ Ireland, 10.-12.12.14, in: Proceedings, 20141-20148 (2014).
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A. Darinskii, M. Weihnacht, H. Schmidt, Surface acoustic wave scattering by substrate edges, IEEE International Ultrasonics
Symposium, in: Proceedings, 2055-2058 (2014).
F. Ding, B. Li, F.M. Peeters, A. Rastelli, V. Zwiller, O.G. Schmidt, Excitons confined in single semiconductor quantum rings:
Observation and manipulation of Aharonov-Bohm-type oscillations, in: Physics of quantum rings, Berlin: Springer-Verl.,
Series: NanoScience and Technology, 299-328 (2014).
S. Doerfler, K. Pinkert, A. Meyer, M. Weiser, H. Althues, L. Giebeler, M. Schneider, J. Eckert, A. Michaelis, E. Beyer, S. Kaskel,
Highly porous carbon electrodes for energy storage and conversion application, International ECEMP Colloquium 2013, Dresden,
25.-26.10.13, in: ECEMP-European Centre for Emerging Materials and Processes Dresden - Ressourcenschonende Werkstoffe Technologien - Prozesse, Verl. Wissenschaftliche Scripten, 427 (2014).
D. Ernst, M. Melzer, D. Makarov, F. Bahr, W. Hofmann, O.G. Schmidt, T. Zerna, Packaging technologies for (Ultra-)thin sensor
applications in active magnetic bearings, 37th International Spring Seminar on Electronics Technology (ISSE), in: Proceedings,
125-129 (2014).
V.M. Fomin, Quantum ring: A unique playground for the quantum-mechanical paradigm, in: Physics of quantum rings,
Berlin: Springer-Verl., Series: NanoScience and Technology, 1-24 (2014).
L. Giebeler, F. Thoss, I. Lindemann, C. Bonatto Minella, B. Boehme, S. Peters, M. Baitinger, J. Grin, J. Eckert, L. Schultz,
Solid state hydrogen storage materials and metallic anodes for mobile and stationary applications, International ECEMP Colloquium
2013, Dresden, 25.-26.10.13, in: ECEMP-European Centre for Emerging Materials and Processes Dresden - Ressourcenschonende
Werkstoffe - Technologien - Prozesse, Verl. Wissenschaftliche Scripten, 385 (2014).
S. Giudicatti, S.M. Marz, S. Boettner, B. Eichler, M.R. Jorgensen, O.G. Schmidt, Rolled-up TiO2 microtubes for photonics
applications, in: SPIE Proceedings, Photonic Crystal Materials and Devices XI, 9127, 912706/1- (2014).
G. Hrkac, K. Butler, T.G. Woodcock, T. Schrefl, O. Gutfleisch, Impact of different Nd-rich and Cu-doped crystal-phases on the
coercivity of Nd-Fe-B grain ensembles, 23nd International Workshop on Rare Earth and Future Permanent Magnets and their
Applications, Annapolis/ USA, 17.-21.8.14, in: Proceedings, 279-281 (2014).
R. Huehne, S. Trommler, P. Pahlke, L. Schultz, Low temperature performance of Pb(Mg1/3Nb2/3)0.72Ti0.28O3 single crystals
mapped by metallic and superconducting thin films, 2014 Joint IEEE International Symposium on the Applications of Ferroelectrics,
International Workshop on Acoustic Transduction Materials and Devices, in: IEEE Proceedings, 1-4 (2014).
T. Marr, J. Romberg, J. Freudenberger, J. Scharnweber, A. Eschke, C.-G. Oertel, I. Okulov, R. Petters, U. Kuehn, J. Eckert,
L. Schultz, W. Skrotzki, Feines Gefuege, fester Werkstoff, International ECEMP Colloquium 2013, Dresden, 25.-26.10.13, in:
ECEMP-European Centre for Emerging Materials and Processes Dresden - Ressourcenschonende Werkstoffe - Technologien Prozesse, Verl. Wissenschaftliche Scripten, 375 (2014).
G. Martin, E. Chilla, H. Schmidt, B. Steiner, Second-harmonic suppression in DART-SFIT devices, IEEE International Ultrasonics
Symposium, in: Proceedings, 2015-2018 (2014).
M. Mietschke, S. Faehler, L. Schultz, R. Huehne, Influence of the deposition geometry on structural and ferroelectric properties of
epitaxial PMN-PT films, 2014 Joint IEEE International Symposium on the Applications of Ferroelectrics, International Workshop
on Acoustic Transduction Materials and Devices, in: IEEE Proceedings, 1-4 (2014).
T. Mix, L. Schultz, T.G. Woodcock, Crystal structure and hard magnetic properties of Mn-Ga compounds, 23nd International
Workshop on Rare Earth and Future Permanent Magnets and their Applications, Annapolis/ USA, 17.-21.8.14, in: Proceedings,
259-261 (2014).
R. Niemann, A. Diestel, A. Backen, U.K. Roessler, C. Behler, S. Hahn, M.F.-X. Wagner, L. Schultz, S. Faehler, Controlling reversibility
of the magneto-structural transition in first-order materials on the micro scale, 6th International Conference on Magnetic
Refrigeration at Room Temperature (Thermag VI), Victoria/ Canada, 7.-10.9.14, in: Proceedings, 1623/1-2 (2014).
A. Sanchez, V. Magdanz, O.G. Schmidt, S. Misra, Magnetic control of self-propelled microjets under ultrasound image guidance,
5th IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob), Sao Paulo/ Brazil,
12.-15.8.14, in: Proceedings, 169-174 (2014).
S. Sanchez, W. Xi, A.A. Solovev, L. Soler, V. Magdanz, O.G. Schmidt, Tubular micro-nanorobots: Smart design for bio-related
applications, in: Small-Scale Robotics. From Nano-to-Millimeter-Sized Robotic Systems and Applications. Lecture Notes in
Computer Science, Berlin: Springer-Verl., 2014, I. Paprotny, S. Bergbreiter (eds.), 8336, 16-27 (2014).
K. Schulz, D. Ernst, S. Menzel, J., Wolter, K.-J. Eckert, Thermosonic Platinum wire bonding on Platinum, 37th International Spring
Seminar on Electronics Technology, Advances in Electronic System Integration, Dresden/ Germany, 7.-11.5.14, in: Proceedings,
64-65 (2014).
K. Schulz, D. Ernst, S. Menzel, T. Gemming, J. Eckert, K.-J. Wolter, Thermosonic platinum wire bonding on platinum, 37th International Spring Seminar on Electronics Technology (ISSE), Dresden/ Germany, 7.-11.5.14, in: Proceedings, 120-124 (2014).
A.H. Taghvaei, M. Stoica, K. Janghorban, J. Eckert, Ball milling-induced nanocrystallization of Co40Fe22Ta8B30 metallic glass
with high thermal stability and good soft magnetic properties, 5th International Conference on Nanostructures (ICNS5), Institute
for Nanoscience and Nanotechnology (INST), Sharif University of Technology, Tehran/ Islamic Republic of Iran, 6.-9.3.14, in:
Proceedings (Hrsg. M. Reza Ejtehadi), Part 2, 974 (2014).
T.G. Woodcock, Q.M. Ramasse, G. Hrkac, T. Shoji, M. Yano, A. Kato, O. Gutfleisch, Phase boundaries in hot deformed Nd-Fe-Co-B-Ga
magnets infiltrated with a Nd-Cu eutectic liquid, 23nd International Workshop on Rare Earth and Future Permanent Magnets and
their Applications, Annapolis/ USA, 17.-21.8.14, in: Proceedings, 282-284 (2014).
J. Zhao, Q. Deng, S.M. Avdoshenkoe, L. Fu, J. Eckert, M.H. Ruemmeli, Direct in situ observations of single Fe atom catalytic
processes and anomalous diffusion at graphene edges, in: PNAS, 111, 15641-15646 (2014).
Invited talks
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S.-H. Baek, D.V. Efremov, J.M. Ok, J.S. Kim, J. van den Brink, B. Buechner, Orbital-driven nematicity and superconductivity in FeSe:
NMR study, Orbital-driven nematicity and Superconductivity in FeSe: NMR study, Trieste/ Italien, 27.-31.10.14 (2014).
M. Boenisch, M. Calin, A. Panigrahi, T. Waitz, M. Zehetbauer, A. Helth, A. Gebert, L. Giebeler, J. van Humbeeck, W. Skrotzki,
J. Eckert, Displacive and diffusional phase transformations in Ti-Nb alloys, Seminar, Forschungsgruppe Physik funktioneller
Materialien, Universitaet Wien, Wien/ Oesterreich, 10.3.14 (2014).
F. Boerrnert, A flexible multi-stimuli in-situ (S)TEM: Concept, optical performance, and outlook, Ernst Ruska-Centrum,
Forschungszentrum Juelich, 4.11.14 (2014).
F. Boerrnert, A dedicated in-situ (S) TEM, Holo Workshop, Dresden, 10.-12.6.14 (2014).
S. Borisenko, ARPES of iron-based superconductors, International Workshop on Iron-based Superconductors, Beijing/ China,
4.-8.8.14 (2014).
S. Borisenko, ARPES of iron-based superconductors, Multi-Condensates Superconductivity, Erice, Sicily/ Italy, 19.-25.7.14 (2014).
S. Borisenko, ARPES of iron-based superconductors, Multi-Condensate Superconductivity and Superfluidity in Solids and Ultracold
Gases, Camerino/ Italy, 24.-27.6.14 (2014).
S. Borisenko, ARPES of iron-based superconductors, EMN Summer Meeting Energy, Materials and Nanotechnology, Cancun/ Mexico,
9.-12.6.14 (2014).
S. Borisenko, Graphene-like electronic structure in one and three dimensions, 2014 EMN Spring Meeting, Las Vegas, NV/ USA,
27.2.-2.3.14 (2014).
S. Borisenko, ARPES of iron-based superconductors: recent results and current understanding, 4th International Conference on
Superconductivity and Magnetism, Antalya/ Turkey, 27.4.-2.5.14 (2014).
S. Borisenko, ARPES of iron-based superconductors: recent results and current understanding, Seminar at ETH Zuerich, Zuerich/
Switzerland, 13.-14.3.14 (2014).
B. Buechner, Magnetism and nanoscale electronic properties in transition metal oxides, Doctorate Colloquium, Universita degli
Studi di Pavia, Pavia/ Italy, 13.3.14 (2014).
B. Buechner, NMR studies of nanoscale electronic order in high temperature superconductors, Superstripes 2014, Erice, Sicily/
Italien, 25.-31.7.14 (2014).
B. Buechner, Spin Gaps in doped S=1/2 antiferromagnetic Heisenberg chains, IV. International Conference on Superconductivity
and Magnetism (ICSM 2014), Antalya/ Tuerkei, 27.4.-2.5.14 (2014).
B. Buechner, Phase diagrams of Fe based superconductors, CIMTEC 2014, 13th International Conference on Modern Materials and
Technologies, Montecatini Terme, Tuscany/ Italy, 8.-13.6.14 (2014).
B. Buechner, FeSe: a model system for Fe based superconductors, Magnetism, Bad Metals and Superconductivity: Iron Pnictides
and Beyond, Santa Barbara/ USA, 2.-8.11.14 (2014).
B. Buechner, Low dimensional cuprates with antiferromagnetic chains: Spin gaps, ballistic spinon heat transport, and doping
induced spin states, International Symposium Single Crystals: Growth and Physico-Chemical Properties, University of Paris Sud,
Paris/ France, 18.12.14 (2014).
B. Buechner, Spin Gaps in doped S=1/2 antiferromagnetic Heisenberg chains, Symposium of the SFB/TR 49, Koenigstein bei
Frankfurt/ Main, 8.-10.4.14 (2014).
M. Calin, Lessons learned from the coordination of an Initial Training Network (Marie Curie-ITN), Informationsveranstaltung
„Foerderung der Mobilitaet und Karriereentwicklung von Nachwuchswissenschaftler/Innen: Marie Sklodowska Curie-Massnahmen
in Horizon 2020, TU Dresden, 14.1.14 (2014).
M. Calin, Novel Ti-based materials for biomedical applications, Colloquim - Materials Science and Engineering Faculty, University
„Politehnica“ Bucharest, Bucharest/ Romania, 9.4.14 (2014).
M. Calin, M. Boenisch, A. Helth, K. Zhuravleva, N. Zheng, S. Abdi, F.P. Gostin, A. Gebert, J. Eckert, Novel metastable Ti-based
structures for orthopedic applications, Internation Conference ROMAT 2014, Bukarest/ Romania, 15.-17.10.14 (2014).
M. Calin, N. Zheng, S. Abdi, M. Boenisch, A. Helth, M.D. Baro, F.P. Gostin, A. Gebert, J. Eckert, Design of biocompatible Ti-based
amorphous alloys for implant applications, The 15th International Conference of Rapidly Quenched & Metastable Materials
(RQ 15 ), Shanghai/ China, 24.-28.8.14 (2014).
M. Daghofer, Fractional chern insulators in strongly correlated multiorbital systems, DPG Fruehjahrstagung Kondensierte Materie,
Dresden, 3.4.14 (2014).
M. Daghofer, Correlations and topology in multi-orbital models, Theorie-Kolloquium, Universitaet Erlangen, 7.1.14 (2014).
M. Daghofer, The spin-orbit coupled … antiferromagnet in iridates, Workshop „Quantum Phenomena in Strongly Correlated
Electrons“, Krakow/ Poland, 15.-18.6.14 (2014).
M. Daghofer, Itinerant multi-orbital models for Pnictide superconductors, Sommerschule „Multi-Condensates Superconductivity“,
Erice/ Italy, 19.-25.7.14 (2014).
T. Dey, Novel magnetism in Ir-based oxides, Institut für Physik, Universitaet Augsburg, 29.7.14 (2014).
F. Ding, Practical quantum hardware based on semiconductor quantum dots, Seminar TU Dresden, Dresden/Germany, 9.9.14 (2014).
F. Ding, Quantum photonics engineering with semiconductor quantum dots, Seminar Heriot-Watt University, Edinburgh/ UK,
19.8.14 (2014).
J. Eckert, High-strength ultrafine-grained materials with enhanced deformability, 15th International Conference on Rapidly
Quenched and Metastable Materials (RQ 15), Shanghai/ PR China, 26.8.14 (2014).
J. Eckert, Tailoring structure formation and mechanical properties of nanomaterials, 14th International Symposium on Plasticity
and Its Current Applications (Plasticity ‘14), Freeport/ Bahamas, 7.1.14 (2014).
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J. Eckert, Improving the deformability of metallic glasses and composites, 10th International Conference on Bulk Metallic Glasses
(BMG X), Shanghai/ PR China, 4.6.14. (2014).
J. Eckert, Tailoring structure formation and properties of metastable alloys and composites, Symposium on „Frontiers of
Solidification Research“, DLR Koeln, 29.9.14 (2014).
J. Eckert, Neue Materialien auf der Basis metastabiler Phasen, Materialwissenschaftliches Kolloqium, Montanuniversitaet Leoben
and Erich-Schmid Institut fuer Materialwissenschaft der Oesterreichischen Akademie der Wissenschaften, Leoben/ Oesterreich,
10.6.14 (2014).
J. Eckert, Improving the ductility of bulk metallic glasses by mechanical treatment, Global Research Laboratory Korea- Germany
Workshop on Bulk Metallic Glasses and Nanostructured Materials, Jeong Seon/ Korea, 22.8.14 (2014).
J. Eckert, Neue Materialien auf der Basis metastabiler Phasen- Modernes Legierungsdesign am Beispiel von metallischen Glaesern
und nanostrukturierten Kompositen, Technikwissenschaftliche Klasse der Saechsischen Akademie der Wissenschaften zu Leipzig,
Leipzig, 10.10.14 (2014).
J. Eckert, Ductilization of bulk metallic glasses by mechanical treatment, 5th International Conference on Materials Science and
Technologies (RoMat 2014), Bukarest/ Rumaenien, 16.10.14 (2014).
J. Eckert, Complex metallic materials with hierarchical hybrid structures: Tailoring metastable phases for engineering applications,
Materials Science and Engineering Congress (MSE 2014), Darmstadt, 25.9.14 (2014).
S. Faehler, Multifunktionale Materialien: Von den physikalischen Grundlagen zu neuartigen Sensoranwendungen, TU Chemnitz,
14.4.14 (2014).
S. Faehler, Origin of hysteresis in multicaloric materials, THERMAG VI, Victoray, BC/ Canada, 7.-10.9.14 (2014).
S. Faehler, Modulated martensite: A scale bridging Lego game for crystallographers and physicists, DPG Fruehjahrstagung, Dresden,
30.3.-4.4.14 (2014).
S. Faehler, Multifunctional magnetic materials, TU Chemnitz, 16.12.14 (2014).
J. Fink, Untersuchungen zum Mechanismus von konventioneller und unkonventioneller Supraleitung durch winkelaufgeloester
Photoemissionsspektroskopie, Kolloquiumsvortrag, Universitaet Kiel, 21.1.14 (2014).
J. Fink, ARPES experiments on conventional and unconventional superconductors, SpecNovMat Workshop SLS, Passugg-Araschgen/
Schweiz, 27.2.-3.3.14 (2014).
V.M. Fomin, Propulsion mechanism of catalytic jet engines, International Workshop on Micro- and Nanomachines, Hannover/
Germany, 2.-5.7.14 (2014).
V.M. Fomin, Impact of topology on physical properties of quantum rings, Invited Topical Talk, DPG-Fruehjahrstagung,
Spring Meeting of the German Physical Society, Dresden/ Germany, 31.3.14 (2014).
V.M. Fomin, Vortex dynamics in rolled-up superconductor nanostructures, International Conference on Problems of Strongly
Correlated and Interacting Systems, Saint-Petersburg/ Russia, 28.-31.5.14 (2014).
V.M. Fomin, Effects of topology in physical properties of quantum rings, Institutsseminar, Paul-Drude-Institut fuer
Festkoerperelektronik, Berlin/ Germany, 28.4.14 (2014).
V.M. Fomin, Topological effects in physical properties of quantum rings, Seminar, Department of Electrical Engineering,
University of California, Riverside, California/ USA, 13.3.14 (2014).
V.M. Fomin, Dynamics of superconducting vortices in Nb open microtubes, 7th International Conference on Materials Science and
Condensed Matter Physics, Chisinau/ Republic of Moldova, 16.-19.9.14 (2014).
V.M. Fomin, Theoretical modeling of electronic and optical properties of nanostructures: From the non-adiabaticity of semiconductor
nanocrystals to the geometric and topological effects in quantum rings, 3rd International Symposium on Disperse Systems for
Electronic Applications, Erlangen/ Germany, 11.-12.9.14 (2014).
V.M. Fomin, Topological effects in quantum rings, Seminar, Institute of Semiconductor Physics Siberian Branch of the Russian
Academy of Sciences, Novosibirsk/ Russia, 10.10.14 (2014).
V.M. Fomin, Quantum rings: A unique playground for topological effects from doubly connectedness to one sidedness, EMN Spring
Meeting, Las Vegas, Nevada/ USA, 27.2.-2.3.14 (2014).
J. Freudenberger, A. Kauffmann, S. Yin, F. Bittner, D. Seifert, H. Klauss, V. Klemm, W. Schillinger, L. Schultz, Hochfeste
Leitermaterialien auf Kupfer-Basis, 5. Dresdener Werkstoffsymposium, Dresden, 8.-9.12.14 (2014).
J. Freudenberger, A. Kauffmann, S. Yin, F. Bittner, D. Seifert, H. Klauss, V. Klemm, W. Schillinger, L. Schultz, Hochfeste
Kupferleiter, DGM Fachausschuss Werkstoffe der Energietechnik, Dresden, 18.-19.3.14 (2014).
A. Gebert, New Ti-based alloys for implant applications, Werkstoffkolloquium Universitaet Erlangen-Nuernberg, Erlangen,
15.4.14 (2014).
A. Gebert, A. Helth, K. Zhuravleva, S. Abdi, P.F. Gostin, M. Calin, U. Hempel, R. Medda, E.A. Cavalcanti-Adam, J. Eckert, Tailoring
the surfaces of metastable Ti-based alloys at the nanoscale for biomedical applications, 5th International Conference on Materials
Science and Technology, RoMat 2014, Bucharest/ Romania, 15.-17.10.14 (2014).
A. Gebert, A. Helth, K. Zhuravleva, M. Boenisch, P.F. Gostin, S. Oswald, M. Calin, J. Eckert, New Ti-Nb-based alloys for implant
applications, Indo-German Workshop: Strategies for Improved Bone Replacement Materials and Orthopeadic Implants- DesignManufactoring- Technologies, TU Dresden, Universitaetsklinikum Carl Gustav Carus, Dresden, 19.-21.2.14 (2014).
J. Geck, Collective phenomena in strongly interacting electron systems, Kolloquium, Goettingen, 20.5.14 (2014).
J. Geck, Charge density wave order in 1T-TaS2 and its relation to superconductivity, Superstripes Konferenz 2014, Erice/ Italien,
19.-25.7.14 (2014).
J. Geck, Emergent phenomena in complex electron systems, Eingeladener Vortrag, Universitaet Heidelberg, 14.1.14 (2014).
J. Geck, Resonant x-ray spectroscopies in today’s materials research, Kolloquium, Salzburg/ Oesterreich, 22.5.14 (2014).
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T. Gustmann, 3D laser beam melting at IFW Dresden, Gruppentreffen mit der Gruppe: Selektives Laserstrahlschmelzen,
des SFB 814: Additive Fertigung (FAU Erlangen-Nuernberg), Erlangen, 3.12.14 (2014).
J. Haenisch, K. Iida, F. Kurth, S. Trommler, E. Reich, V. Grinenko, B. Holzapfel, L. Schultz, C. Tarantini, J. Jaroszynski,
T. Foerster, High field transport properties of superconducting Ba(Fe1-xCox)2As2 thin films, EMFL User Meeting, HZDR, Dresden,
19.6.14 (2014).
W. Haessler, Supraleitung - nur ein interessantes physikalisches Phaenomen oder auch Basis sinnvoller Anwendungen?,
Vortrag am Tag der Wissenschaften am BSZ Radebeul, Radebeul, 18.6.14 (2014).
V. Hoffmann, Advances in glow discharge spectrochemistry, 2014 Winter Conference on Plasma Spectrochemistry, Amelia Island,
Florida/ USA, 6.-11.1.14 (2014).
R. Huehne, Highly textured templates for the growth of superconducting thin films, 17th International Conference on Textures of
Materials (ICOTOM), Dresden, 24.-29.8.14 (2014).
Y.H. Huo, Molecular beam epitaxy and its application in growing novel quantum structures, Seminar, East China Research Institute
of Electronic Engineering, Hefei/ China 10.11.14 (2014).
Y.H. Huo, Stretching quantum dots from heavy to light, International Conference of Young Researchers on Advanced Materials,
Haikou/ China, 24.-29.10.14 (2014).
Y.H. Huo, Novel QDs grown in GaAs/AlGaAs system: Fabrication and characterization, Seminar, Hefei Nation Laboratory for Physical
Sciences at the Microscale, University of Science and Technology of China, Hefei/ China, 16.1.14 (2014).
Y.H. Huo, Highly symmetric GaAs quantum dots grown on GaAs (001) substrate, Seminar, School of Physics and Engineering,
Sun Yat-Sen University, Guangzhou/ China, 13.1.14 (2014).
Y.H. Huo, A light-hole exciton in a quantum dot, Seminar, Institute of Semiconductors, Chinese Academy of Sciences, Beijing/
China, 9.1.14 (2014).
D. Karnaushenko, Printable magnetic sensors, 41st International IARIGAI Conference Swansea/ United Kingdom,
7.-10.9.14 (2014).
V. Kataev, Low-energy spin dynamics of the spin-orbital Mott insulator Sr2IrO4, Moscow International Symposium on Magnetism
MISM-2014, Moscow/ Russia, 29.6.-3.7.14 (2014).
V. Kataev, Probing the spin dynamics in novel Iridium oxides by sub-THz ESR, Asia-Pacific EPR/ESR Symposium, Nara/ Japan,
12.-16.11.14 (2014).
V. Kataev, Broad-band high-frequency ESR spectroscopy of strongly correlated quantum magnets, 9th Meeting of the European
Federation of EPR, EF-EPR2014, Marseille/ Frankreich, 7.-11.9.14 (2014).
V. Kataev, Interplay of site disorder and magnetic frustration in the quantum spin magnet CoAl2O4, Seminar at the Molecuar
Photoscience Research Center, Kobe University, University of Kobe, Kobe/ Japan, 4.11.14 (2014).
V. Kataev, Order-by-disorder in the frustrated quantum spin magnet COAl204, International Conference „Modern Development of
Magnetic Resonance“ 2014, Kazan/ Russland, 23.-27.9.14 (2014).
V. Kataev, Tunable sub-THz ESR spectroscopy on the spin-orbital Mott insulator Sr2IrO4, International Conference on
Superconductivity and Magnetism- ICSM2014, Antalya/ Tuerkei, 27.4.-2.5.14 (2014).
V. Kataev, High field ESR spectroscopy on correlated magnetic oxides, Condensed Matter Physics Seminar, KIP, Heidelberg
University, Heidelberg/ Germany, 16.5.14 (2014).
M. Knupfer, Interfaces of archetype magnetic molecules: from interface dipoles to charge and spin transfer, Fruehjahrstagung der
DPG, Dresden 2014, Dresden, 31.3.-4.4.14 (2014).
K. Leistner, Control of magnetism in nanostructured materials by structure, microstructure and electric field, Sonderkolloquium,
Institut fuer Materialphysik, Westfaelische Wilhelms-Universitaet Muenster, Muenster, 6.11.14 (2014).
K. Leistner, Magnetism: A playground for material scientists and electrochemists, Materialphysikalisches Kolloquium, Institut fuer
Materialphysik, Westfaelische Wilhelms-Universitaet Muenster, Muenster, 21.7.14 (2014).
V. Magdanz, Development of a sperm flagella driven micro-bio-robot, 3rd World Congress on Reproduction, Oxidative Stress and
Antioxidants, Paris/ France, 22.-23.5.14 (2014).
D. Makarov, Flexible and printable magnetic field sensors, INNOMAG Mitgliederversammlung Fraunhofer-Institut ICT-IMM, Mainz/
Germany, 31.10.14 (2014).
D. Makarov, Magnetic nanomembranes, Physikkolloquium, Johannes Kepler Universitaet Linz, Linz/ Austria, 5.6.14 (2014).
D. Makarov, Shapeable magnetoelectronics, Naturwissenschaftliche Fakultaet, Universitaet Salzburg, Salzburg/ Austria,
2.6.14 (2014).
D. Makarov, Curved magnetic nanomembranes, Institut fuer Materialphysik, Westfaelische Wilhelms-Universitaet Muenster,
Muenster/ Germany, 20.5.14 (2014).
D. Makarov, Magnetic tubular architectures, Seminar, Department of Physics, Universidad Tecnica Federico Santa Maria,
Valparaiso/ Chile, 24.3.14 (2014).
D. Makarov, Spin-orbit coupling effects in magnetic sandwiches, Seminar, Department of Physics, Universidad Tecnica Federico
Santa Maria, Valparaiso/ Chile, 24.3.14 (2014).
D. Makarov, Magnetism in curved geometries, Institute of Physics, Johannes Gutenberg-Universitaet Mainz Mainz/ Germany,
29.4.14 (2014).
D. Makarov, Magnetism in curved surfaces, Seminar, Department of Physics, Universidad Tecnica Federico Santa Maria,
D. Makarov, Imperceptible magnetoelectronics, Seminar, Department of Physics, Universidad Tecnica Federico Santa Maria,
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D. Makarov, Flexible Hall effect sensors for automotive applications, Seminar, Department of Physics, Universidad Tecnica Federico
Santa Maria, Valparaiso/ Chile, 26.3.14 (2014).
D. Makarov, Flexible, stretchable and printable magnetic sensorics, Seminar of the DPG, TU Dresden, Dresden/ Germany,
21.1.14 (2014).
D. Makarov, 3D magnetic architectures, Workshop on Magnetoplasmonics, Uppsala University Uppsala/ Sweden, 17.-19.2.14
(2014).
D. Makarov, Shapeable magnetic sensorics, Edgar Luescher Seminar, Klosters/ Switzerland, 1.-7.02.14 (2014).
D. Makarov, V. Lozovski, Local-field effects in magnetoplasmonic nanostructures, Workshop on Magnetoplasmonics,
Uppsala University Uppsala/ Sweden, 17.-19.2.14 (2014).
M. Melzer, Stretchable magnetoelectronics, Edgar Luescher Seminar, Klosters/ Switzerland, 1.-7.02.14 (2014).
M.R. Mueller, S. Menzel, U. Kuenzelmann, I. Petrov, J. Knoch, K. Kallis, Tackling hillocks growth after Aluminum CMP,
International Conference on Planarization/CMP Technology (ICPT) 2014, Kobe/ Japan, 19.-21.11.14 (2014).
V. Neu, Epitaxial Rare-Earth Cobalt thin films and multilayers: Tuning anisotropies and functionality, Semiar at IMDEA Nanoscience,
Madrid/ Spain, 5.11.14 (2014).
V. Neu, Principles and possibilities of quantitative magnetic force microscopy, Seminar at the Instituto de Ciencia de Materiales de
Madrid, Madrid/ Spain, 4.11.14 (2014).
V. Neu, S. Sawatzki, F. Wehrmann, C. Damm, L. Schultz, Exchange coupled SmCo5/Fe (Co) multilayers, Workshop on Rare Earth and
Future Permanent Magnets REPM’14, Annapolis/ USA, 17.-21.8.14 (2014).
V. Neu, S. Sawatzki, F. Wehrmann, C. Damm, L. Schultz, Exchange coupled SmCo5/Fe(Co) multilayers, Seminar at the Instituto de
Magnetismo Aplicado, Madrid/ Spain, 6.11.14 (2014).
R. Niemann, J. Baro, J. Kopecek, O. Heczko, J. Romberg, L. Schultz, S. Faehler, E. Vives, L. Manosa, A. Planes, Microstructural
origin of avalanches during the martensitic transformation, Avalanches in Functional Materials and Geophysics Workshop,
Magdalene College, Cambridge/ UK, 4.-8.12.14 (2014).
R. Niemann, S. Kauffmann-Weiss, C. Behler, A. Diestel, A. Backen, U.K. Roessler, H. Seiner, O. Heczko, S. Hahn, M.F.-X. Wagner,
L. Schultz, S. Faehler, Martensitic transformation in epitaxial magnetic shape memory films, Seminar of Device Materials Group,
Department of Materials Science and Metallurgy, University of Cambridge, Cambridge/ UK, 8.12.14 (2014).
R. Pfrengle, Kooperation und Durchlaessigkeit der Bildungssysteme, Beitrag zur Podiumsdiskussion auf der Fachtagung der IHK
Dresden, Dresden, 24.11.14 (2014).
R. Pfrengle, Impact der Physik: Wissens- und Technologietransfer, Beitrag zur Podiumsdiskussion auf dem 35. Jahrestag der
Deutschen Physikalischen Gesellschaft, Bad Honnef, 21.11.14 (2014).
R. Pfrengle, K. Backhaus-Nousch, Research in the field of professional and personal development of academic workers, Vorlesung
im Rahmen der International Conference on Development and Implementation of Academic Competencies of PhD students of
Technical Sciences an der Slovak University of Technology in Bratislava (Akademisches Jahr 2013/2014), Trnava/ Slowakei,
24.4.14 (2014).
R. Pfrengle, K. Backhaus-Nousch, Research in the field of professional and personal development, Vorlesung im Rahmen des
gemeinsamen International Doctoral Seminar 2014 der University of Zielona Gora und der Slovak University of Technology in
Bratislava, Zielona Gora/ Polen, 19.-21.5.14 (2014).
D. Pohl, S. Schneider, J. Rusz, B. Rellinghaus, STEM with electron vortex beams - A route toward local EMCD measurements?,
Colloqium in Transmission Electron Microscopy, Uppsala/ Schweden, 5.-6.9.14 (2014).
D. Pohl, A. Surrey, B. Bieniek, U. Wiesenhuetter, E. Mohn, F. Schaeffel, L. Schultz, B. Rellinghaus, Segregation phenomena in
binary nanoparticles studied by aberration-corrected HRTEM, Eingeladener Vortrag - Institutsseminar Strukturphysik TU Dresden,
14.1.14 (2014).
B. Rellinghaus, Phase stabilities in alloy nanoparticles, Vortrag im Physikalischen Kolloquium, Universitaet Kassel, Kassel,
12.6.14 (2014).
B. Rellinghaus, D. Pohl, A. Surrey, B. Bieniek, L. Schultz, The effect of surfaces and interfaces on the phase stability of nanoscopic
alloys, International Conference on Small Science, ICSS 2014, Hong Kong/ China, 8.-11.12.14 (2014).
B. Rellinghaus, D. Pohl, A. Surrey, F. Schmidt, S. Wicht, S. Schneider, L. Schultz, Exploring the structure-property relation of
metallic nanoparticles at the atomic scale, Institutsseminar, Okinawa Institute of Science and Technology, OIST, Okinawa/ Japan,
5.12.14 (2014).
B. Rellinghaus, D. Pohl, A. Surrey, U. Wiesenhuetter, B. Bieniek, L. Schultz, Phase stabilities at small lentgh scales,
5th International Conference on Materials Science and Technology, RoMat 2014, Bucharest/ Romania, 15.-17.10.14 (2014).
M. Richter, Organo-metallic complexes with the largest possible magnetic anisotropy, Seminar der FOR 1282, TU Berlin, Berlin,
26.6.14 (2014).
R. Schaefer, Energy-related aspects of magnetic microstructure, TMS 2014 Konferenz, San Diego/ USA, 19.2.14 (2014).
R. Schaefer, Magneto-optical analysis of magnetic microstructure, Seminar am Int. Lab. of High Magnetic Fields, Wroclaw/ Poland,
30.5.14 (2014).
R. Schaefer, Magnetic domains and flux propagation in bulk magnetic material, Verleihung Barkhausenpreis, Dresden,
7.3.14 (2014).
R. Schaefer, Magneto-optical analysis of magnetic microstructure, Seminar an University of Electronic Science and Technology,
Chengdu/ China, 15.7.14 (2014).
R. Schaefer, Analysis of magnetic microstructure, Seminar at the UGC-DAE Consortium for Scientific Research, Indore/ Indien,
31.10.14 (2014).
123) R. Schaefer, Magetische Domaenen, Schulung im Forschungszentrum der Robert Bosch AG, Gerlingen, 11.6.14 (2014).
124) R. Schaefer, Magneto-optical Kerr microscopy, Schulung an Fudan University, Inst. of Physics, Shanghai/ China,
16.-18.6.14 (2014).
125) R. Schaefer, Some insufficiently explored aspects of magnetic microstructure, Workshop „Micromagnetics: Analysis and
Applications, Heidelberg, 4.8.14 (2014).
126) R. Schaefer, Magnetic domain analysis by Kerr microscopy, Blockseminar an University of Electronic Science and Technology,
Chengdu/ China, 15.-17.7.14 (2014).
127) R. Schaefer, Magneto-optical Kerr microscopy, Kurs am UGC-DA Consortium for Scientific Research, Indore/ Indien,
26.-27.8.14 (2014).
128) R. Schaefer, Magnetic domains and flux propagation in bulk magnetc material, MSE 2014 Konferenz, Ehrenkolloquium Prof. Schultz,
Darmstadt/ Germany, 24.9.14 (2014).
129) R. Schaefer, Magnetic domains and flux propagation in electrical steel, Seminar am Ford Research Lab in Dearborn, Dearborn/ USA,
10.10.14 (2014).
130) R. Schaefer, Magnetic measurements, Vorlesung auf IEEE Magnetics Summer School 2015, Rio de Janeiro/ Brazil, 15.8.14 (2014).
131) R. Schaefer, Magneto-optical Kerr microscopy, Seminar am Indian Institute for Science, Inst. of Physics, Bengalore/ Indien,
28.10.14 (2014).
132) R. Schaefer, Magneto-optical Kerr microscopy, Kurs am Oakridge Natioal Laboratory, Oakridge/ USA, 3.10.14 (2014).
133) H. Schloerb, Elektrochemische Abscheidung nanoskaliger Magnete, Kolloquium der Bezirksgruppe Sachsen der Deutschen
Gesellschaft für Oberflaechentechnik (DGO), IFW Dresden, 18.6.14 (2014).
134) H. Schloerb, Electrodeposited nanoscaled magnets, Seminarvortrag, Jozef-Stefan-Institut Ljubljana/ Slowenien, 24.10.14 (2014).
135) H. Schloerb, V. Haehnel, C. Konczak, D. Pohl, A. Funk, S. Oswald, C. Damm, L. Schultz, Recent progress on electrodeposition of
magnetic iron-based alloy films and nanowires, 226th Meeting of the Electrochemical Society, Cancun/ Mexico, 5.-8.10.14 (2014).
136) F. Schmidt, D. Pohl, L. Schultz, B. Rellinghaus, A TEM study on nanoparticles: segregation, light element detection and surface
energy, Eingeladener Vortrag, IMA, Universitaet Madrid, Madrid/ Spanien, 3.-8.11.14 (2014).
137) O.G. Schmidt, Inorganic nanomembranes for paradigm shifting technologies, Seminar, Shanghai Tech University, Shanghai/ China,
14.5.14 (2014).
138) O.G. Schmidt, Inorganic nanomembranes for paradigm shifting technologies, Colloquium, King Abdullah University, Jeddah/ Saudi
Arabia, 22.4.14 (2014).
139) O.G. Schmidt, Materialien, Architekturen und Integration von Nanomembranen, Barkhausen-Festkolloquium, Dresden/ Germany,
7.3.14 (2014).
140) O.G. Schmidt, Nanomembrane devices for microfluidic devices, Graduate Summer School on Nanoparticles and Microfluidics in
Biosensorics, Bodrum/ Turkey, 1.-7.9.14 (2014).
141) O.G. Schmidt, Inorganic nanomembranes for flexible and ultra-compact device architectures, Seminar, Soochow University,
Suzhou City/ China, 12.5.14 (2014).
142) O.G. Schmidt, Inorganic nanomembranes for flexible and ultra-compact microsystem architectures, Seminar, CAS Institute of
Microsystem and Information Technology, Shanghai/ China, 9.5.14 (2014).
143) O.G. Schmidt, From microjet engines to sperm driven micro-biorobots, Workshop on Future Challenges in Nanorobotics Hongkong/
China, 1.6.14 (2014).
144) O.G. Schmidt, Inorganic nanomembranes for paradigm shifting technologies, Seminar, Hefei University of Technology Hefei/ China,
4.6.14 (2014).
145) O.G. Schmidt, Selected topics in nanomaterials II, Lecture, Fudan University, Shanghai/ China, 28.10.14 (2014).
146) O.G. Schmidt, Nanophotonics with nanomembranes, Sino-Germany Bilateral Symposium on Nano-Photonics and NanoOptoelectronics, Changsha/ China, 22.-27.10.14 (2014).
147) O.G. Schmidt, Rolled-up microtube optical ring resonators - from fabrication to sensing, 560. Wilhelm und Else Heraeus-Seminar
„Taking Detection to the Limit: Biosensing with optical microcavities“Bad Honnef/ Germany, 14.-18.4.14 (2014).
148) O.G. Schmidt, Selected topics in nanomaterials I, Lecture, Fudan University, Shanghai/ China, 28.10.14 (2014).
149) O.G. Schmidt, Flexible and shapeable nanomembranes for applications in and with fluids, Flow14, University of Twente, Enschede/
The Netherlands, 18.-21.5.14 (2014).
150) O.G. Schmidt, Inorganic and hybrid nanomembranes: From flexible magneto-electronics to micro-biorobotic applications, Seminar,
Shenyang Institute of Automation, Chinese Academy of Sciences, Shenyang/ China, 3.11.14 (2014).
151) O.G. Schmidt, Inorganic nanomembranes: From flexible magneto-electronics to micro-biorobotic applications, Seminar,
University of Electronic Science and Technology of China, Chengdu/ China, 30.10.14 (2014).
152) O.G. Schmidt, Tubular microanalytic systems for on- and off- chip applications, International Seminar on Lab on Chip Biosensor
Systems, Kusadasi/ Turkey, 7.-11.9.14 (2014).
153) O.G. Schmidt, Electro-elastic quantum photonic devices, The 2nd International Conference on Nanogenerators and Piezotronics
Atlanta, Georgia/ USA, 9.-11.6.14 (2014).
154) O.G. Schmidt, Inorganic nanomembranes for paradigm shifting technologies, Seminar, University of Science and Technology China
Hefei/ China, 5.6.14 (2014).
155) O.G. Schmidt, From bubble-propelled microjets to flagella-driven spermbots, International Workshop on Micro- and Nanomachines,
Hannover/ Germany, 2.-5.7.14 (2014).
156) L. Schultz, Elektrische und magnetische Funktionswerkstoffe fuer energietechnische Anwendungen, Eingeladener Vortrag /
5. Dresdner Werkstoffsymposium 2014, Dresden, 8.-9.12.14 (2014).
157) L. Schultz, Vom Schweben auf Magnetfeldern - die wundersame Welt der Supraleitung, Workshop MS 60 - Von Methoden und
Simulationen bis Mobilitaet und Supraleitung, TU Chemnitz, 22.4.14 (2014).
158) L. Schultz, High temperature superconductors and their application for levitation, Plenary Talk / METAL 2014, 23rd International
Conference on Metallurgy and Materials, Brno/ Czech Republic, 21.-23.5.14 (2014).
159) L. Schultz, O. de Haas, D. Berger, L. Kuehn, A. Berger, T. Espenhahn, Basics of superconducting levitation and its use in the transport system SupraTrans II, Invited Talk / 14th International Symposium on Magnetic Bearings, Linz/ Austria, 11.-14.8.14 (2014).
160) L. Schultz, A. Kirchner, High temperature superconductors for superconducting levitation, Plenary Talk / MSE 2014 - International
Conference on Materials Science and Engineering, Darmstadt, 23.-25.9.14 (2014).
161) L. Schultz, A. Kirchner, Interaction of ferromagnetic and superconducting permanent magnets: Superconducting levitation,
Physics Colloquium at Johannes Gutenberg University, Mainz, 9.12.14 (2014).
162) L. Schultz, A. Kirchner, Nanostructured high temperature superconductors for superconducting levitation, OZ-14 Ceremonial Lecture/
7th German-Japanese International Symposium on Nanostructures, Wenden/ Olpe, 2.-4.3.14 (2014).
163) L. Schultz, D. Pohl, U. Wiesenhuetter, A. Surrey, B. Rellinghaus, Phase stabilities at the nanoscale: Segregation tendencies in
small particles, 15th International Conference on Rapidly Quenched and Metastable Materials, RQ15, Shanghai/ China,
24.-28.8.14 (2014).
164) L. Schultz, J. Thielsch, Interaction of ferromagnetic and superconducting permanent magnets- Superconducting levitation, Invited
Talk / 10th International Conference on the Scientific and Clinical Applications of Magnetic Carriers, Dresden, 10.-14.6.14 (2014).
165) R. Streubel, Towards magnetic x-ray tomography, Seminar, University of California, Santa Cruz/ USA, 14.11.14 (2014).
166) R. Streubel, Imaging 3D spin textures in non-planar architectures, Seminar, University of California, Berkeley/ USA, 12.8.14 (2014).
167) R. Streubel, Controlling topological charges by imprinting non-collinear spin textures, Conference on Magnetism and Magnetic
Materials (MMM), Honolulu/ USA, 3.-7.11.14 (2014).
168) J. van den Brink, Quantum chemistry results on magnetic iridates, Workshop Magnetism, Bad Metals and Superconductivity:
Iron Pnictides and Beyond, KITP Santa Barbara/ USA, 7.11.14 (2014).
169) J. van den Brink, Resonant Inelastic X-ray scattering on high Tc cuprates, iron pnictides and magnetic iridates, Workshop
Magnetism, Bad Metals and Superconductivity: Iron Pnictides and Beyond, KITP Santa Barbara/ USA, 10.10.14 (2014).
170) J. van den Brink, Resonant inelastic X-ray scattering on magnetic iridates compared to quantum chemistry calculations,
IXS Workshop at Stanford Institute for Materials and Energy Sciences, Menlo Park/ USA, 23.9.14 (2014).
171) J. van den Brink, The light that resonant inelastic X-ray scattering sheds on spin and orbital excitations, Workshop Quantum
Phenomena in Strongly Correlated Electrons, Cracow/ Poland, 16.6.14 (2014).
172) J. van den Brink, Resonant inelastic X-ray scattering on high Tc cuprates and magnetic iridates, Moscow International Symposium
on Magnetism, Moscow/ Russia, 1.7.14 (2014).
173) J. van den Brink, Resonant inelastic X-ray scattering on magnetic iridates compared to quantum chemistry calculations,
International Workshop on Mott Physics beyond the Heisenberg Model, Oxford/ UK, 17.9.14 (2014).
174) J. van den Brink, Resonant inelastic X-ray scattering on correlated magnets, Beijing International Workshop (II) on Iron-Based
Superconductors, Chinese Academy of Sciences, Beijing/ China, 7.8.14 (2014).
175) J. van den Brink, Quantum spin dynamics probed by resonant inelastic X-ray scattering, Workshop on Quantum Spin Dynamics,
Dresden/ Germany, 3.9.14 (2014).
176) J. van den Brink, Resonant inelastic X-ray scattering on high Tc cuprates and magnetic iridates, 32nd International Conference
on the Physics of Semiconductors, Austin/ USA, 12.8.14 (2014).
177) J. van den Brink, Workshop summary and outlook, International Workshop on Mott Physics beyond the Heisenberg Model, Oxford/
UK, 18.9.14 (2014).
178) J. van den Brink, Resonant inelastic X-ray scattering on elementary excitations, PSI Summer School on Condensed Matter Research,
Zugerberg/ Switzerland, 15.8.14 (2014).
179) S. Wicht, V. Neu, B. Rellinghaus, O. Mosendz, V. Mehta, S. Jain, O. Hellwig, D. Weller, Atomic resolution structure-property relation
in L10-FePt-based HAMR media, Eingeladener Vortrag, INTERMAG 2014 Dresden, Dresden, 4.-8.5.14 (2014).
180) S. Wicht, V. Neu, L. Schultz, O. Mosendz, V. Mehta, S. Jain, O. Hellwig, D. Weller, B. Rellinghaus, Influence of the interfacial
contact on the magnetic performance of granular FePt media, HGST and Western Digital, San Jose/ USA, 5.-10.4.14 (2014).
181) A. Winkler, Microfluidics using surface acoustic waves, Microfluidics Bio Workshop 2014, TU Dresden, Bad Schandau,
10.6.14 (2014).
182) U. Wolff, Magnetic force microscopy - A tool to study qualitatively and quantitatively superconducting and magnetic structures,
Seminar, Angstoemlaboratoriet, Department Physics and Astronomy, Uppsala/ Sweden, 11.-13.6.14 (2014).
183) T.G. Woodcock, Multiscale characterisation and modelling of Nd-Fe-B permanent magnets, Invited Talk at the International
Laboratory of High Magnetic Fields and Low Temperatures, Polish Academy of Sciences, Wroclaw/ Poland, 3.6.14 (2014).
184) T.G. Woodcock, Multiscale characterisation and modelling of Nd-Fe-B permanent magnets, Materialphysikalisches Kolloquium,
Institut fuer Materialphysik, Westfaelische Wilhems-Universitaet Muenster, Muenster, 14.7.14 (2014).
185) T.G. Woodcock, Q.M. Ramasse, G. Hrkac, T. Schrefl, O. Gutfleisch, Microstructure at the atomic scale and coercivity in Nd-Fe-B
magnets, INTERMAG 2014, Symposium „Recent Developments in Permanent Magnets“, Dresden, 4.-8.5.14 (2014).
186) E. Zallo, Control of electronic and optical properties of single and double quantum dots via growth and electroelastic fields, Seminar,
Cavendish Laboratory, University of Cambridge, Cambridge/ UK, 10.12.14 (2014).
187) E. Zallo, Control of electronic and optical properties of single and double quantum dots via growth and electroelastic fields, Seminar,
Paul-Drude-Institut fuer Festkoerperelektronik, Berlin/ Germany, 11.11.14 (2014).
104 Patents
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Verfahren für die Positionierung von Mikrostrukturelementen (07.01.2014)
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Verfahren zur Herstellung von Mkirofluidsystemen (30.01.2014)
Inventors: Stefan Harazim, Samuel Sanchez, Oliver G. Schmidt
DE 10 2009 002 605
(10912)
Unidirektionaler Wandler für akustische Oberflächenwellen (13.02.2014)
Inventors: Günter Martin, Bert Wall
JP 2012-506481
(11006)
Wandler mit natürlicher Unidirektionalität für akustische Oberflächenwellen (20.03.2014)
Inventors: Günter Martin, Manfred Weihnacht, Sergey Biryukov, Alexander Darinski, Bert Wall
AT 513 436
(11006)
RU 2522035
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EP 2399282
(10903)
Integrierte Schaltkreise enthaltend Isolationsmaterial und dessen Verwendung in
integierten Schaltkreise (09.04.2014)
Inventors: Ehrenfried Zschech, Helmut Hermann, Konstantin Zagarodniy, Gotthard Seifert
DE 10 2009 021 508
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Selbstpassivierende Elektrodensysteme für mikroakustische Bauteile (22.05.2014)
Inventors: Christoph Eggs, Frederik Fabel, Siegfried Menzel, Mario Spindler
EP 1922426
(10506)
Verfahren zur Herstellung und Verwendung von Halbzeug auf Nickelbasis mit
Rekristallisationswürfeltextur (11.06.2014)
Inventors: Jörg Eickemeyer, Dietmar Selbmann, Horst Wendrock, Bernhard Holzapfel
DE 10 2013 201 977
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Verfahren und Vorrichtung zur Präparation von Proben für transmissionselektronenmikroskopische
Untersuchungen (03.07.2014)
Inventors: Volker Hoffmann, Vavara Efimova, Jürgen Thomas, Thomas Gemming, Samuel Grasemann,
Alexander Horst, Steffen Grundkowski, Ralf Voigtländer, Swen Marke, Michael Analytis
US 12/995,618
(10915)
Bauelement aus einem ferromagnetischen Formgedächtnismaterial und dessen Verwendung (22.07.2014)
Inventors: Sebastian Fähler, Jeffrey McCord, Miheala Buschbeck, Oleg Heczko, Michael Thomas
DE 10 2012 205107
(11205)
Akustisches Oberflächenbauelement (07.08.2014)
Inventors: Günter Martin, Bernd Steiner
DE 10 2012 211 013
(11210)
Verfahren zur Herstellung von wasserfreiem Ammoniumtrivanadat und wasserfreies
Ammoniumtrivanadat (07.08.2014)
Inventors: Galina Zakharova, Christine Täschner, Albrecht Leonhardt
DE 10 2013 225 940
(11364)
Verfahren zur Herstellung von massiven Kalibrationsproben für die analytische Spektrometrie (06.10.2014)
Inventors: Volker Hoffmann, Sven Donath, Harald Merker
DE 10 2008 001 986
(10722)
Formkörper aus einem magnesiumhaltigen Verbundwerkstoff und Verfahren zu seiner Herstellung
(30.10.2014)
Inventors: Miroslava Sakaliyska, Jürgen Eckert, Kumar Babu Sureddi, Sergio Scudino
DE 10 2008 001 987
(10723)
Formkörper aus einem aluminiumhaltigen Verbundwerkstoff und Verfahren zu seiner Herstellung
(30.10.2014)
Inventors: Miroslava Sakaliyska, Jürgen Eckert, Kumar Babu Sureddi, Sergio Scudino
EP 11779110.3
(11009)
Hochfeste, bei Raumtemperatur plastisch verformbare und mechanische Energie absorbierende
Formkörper aus Eisenlegierungen (05.11.2014)
Inventors: Uta Kühn, Jürgen Eckert, Uwe Siegel, Julia Kristin Hufenbach, Min Ha Lee
DE 10 2014 211 901
(11414)
Batterieträger (27.11.2014)
Inventors: Markus Herklotz, Jonas Weiß, Lars Giebeler, Michael Knapp
DE 10 2010 041 973
(11009)
Bauelement auf der Basis akustischer Oberflächenwellen (19.12.2014)
Inventors: Günter Martin, Bert Wall
Patents 105
Priority Patent Applications
11401
Verfahren zur Herstellung von amorphen metallischen Partikeln (21.03.2014)
Inventors: Uta Kühn, Sven Donath, Michael Franke
11402
Verfahren zur Herstellung der Beweglichkeit von immobilen Zellen (31.01.2014)
Inventors: Oliver G. Schmidt
11406
Anodenmaterial für Lithium-Ionen-Batterien (01.04.2014)
Inventors: Maik Scholz, Rüdiger Klingeler, Marcel Haft, Sabine Wurmehl, Silke Hampel, Franziska Hammerath,
Bernd Büchner
11407
Wandler für akustische Oberflächenwellen mit einer natürlichen Vorzugsrichtung bei der Wellenabstrahlung (09.04.2014)
Inventors: Günter Martin
11411
Verfahren zur Herstellung von sphärischen Silizium-Kohlenstoff-Nanokompositen,
sphärische Silizium-Kohlenstoff-Nanokomposite und deren Verwendung (04.06.2014)
Inventors: Tony Jaumann, Lars Giebeler, Jürgen Eckert
11413
Hochfeste, mechanische Energie absorbierende und korrosionsbeständige Formkörper aus Eisenlegierungen
und Verfahren zu deren Herstellung (01.09.2014)
Inventors: Josephine Zeisig, Julia Kristin Hufenbach, Uta Kühn, Jürgen Eckert
11414
Batterieträger (20.06.2014)
Inventors: Markus Herklotz, Jonas Weiß, Lars Giebeler, Michael Knapp
11415
Ultrakompakter Mikrokondensator und Verfahren zu seiner Herstellung (05.11.2014)
Inventors: Daniel Grimm, Martin Bauer, Oliver G. Schmidt
11416
Verfahren zur Rückgewinnung von Metallen der Seltenen Erden aus SE-Fe-enthaltendem Material (22.08.2014)
Inventors: Martina Moore, Annett Gebert, Mihai Stoica, Wolfgang Löser
11418
Capacitor and Process for producing thereof (26.08.2014)
Inventors: Daniel Grimm, Oliver G. Schmidt, Ivoyl Koutsaroff, Shoichiro Suzuki, Koichi Banno
11419
Capacitor and Process for Producing thereof (26.08.2014)
Inventors: Daniel Grimm, Oliver G. Schmidt, Shoichiro Suzuki, Akira Ando, Koichi Banno
11420
Verfahren zur Herstellung von teil- oder vollkristallinen, metastabilen Materialien und teil- oder vollkristalline,
metastabile Materialien (23.10.2014)
Inventors: Simon Pauly, Konrad Kosiba, Uta Kühn, Jürgen Eckert
11424
Verfahren und Vorrichtung zur Ermittlung von Kraftfeldern, Kraftfeldgradienten, Materialeigenschaften oder Massen
mit einem System aus gekoppelten, schwingungsfähigen, balkenartigen Komponenten (12.12.2014)
Inventors: Christopher Reiche, Thomas Mühl, Julia Körner
11426
Kompakter Kondensator und Verfahren zu seiner Herstellung (13.10.2014)
Inventors: Oliver G. Schmidt
11429
Verfahren zur Herstellung eines aufgerollten elektrischen oder elektronischen Bauelementes (24.11.2014)
Inventors: Daniel Grimm, Dmitriy Karnaushenko, Martin Bauer, Daniil Karnaushenko, Denys Makarov, Oliver G. Schmidt
11430
Vorrichtung zur Flüssigkeitszerstäubung und Verfahren zu ihrer Herstellung (06.11.2014)
Inventors: Andreas Winkler, Stefan Harazim, Jürgen Eckert, Oliver G. Schmidt
Trademarks
31427
SAWLab Saxony (13.10.2014)
Lab leaders: Siegfried Menzel, Hagen Schmidt
106 PhD and diploma/master theses
PhD and diploma/master theses
PhD Theses
Mohan Ashwin
Low-Dimensional Quantum Magnets: Single Crystal Growth and Heat Transport Studies, TU Dresden
Dirk Bombor
Transportmessungen an Supraleitenden Eisenpniktiden und Heusler-Verbindungen, TU Dresden
Peixuan Chen
Thermal transport through SiGe superlattices, TU Chemnitz
Ulana Cikalova
Bewertung der Materialermüdung anhand des Skalenverhaltens von thermisch und magnetisch
induzierten Signalen, TU Dresden
Maria Dmitrikapoulou
Investigations of Si-based and Heusler nanostructures, TU Dresden
Jan Engelmann
Spannungsinduzierte Supraleitung in undotierten BaFe2As2-Dünnschichten, TU Dresden
Manuela Erbe
Chemische Lösungsabscheidung von (Y,Gd)Ba2Cu3O7-δ-Dünnschichten:
Untersuchungen zur Eigenschaftsoptimierung, TU Dresden
Piter Gargarella
Phase formation, thermal stability and mechanical behaviour of TiCu-based alloys, TU Dresden
Prashanth Konda Gokuldoss
Selective laser melting nof Al-12Si, TU Dresden
Veronika Haehnel
Elektrochemisch hergestellte Fe-Pd-Schichten und Nanodrähte - Morphologie,
Struktur und magnetische Eigenschaften, TU Dresden
Abdelwahab H. A. Hamdy
Electrical properties of different kinds of multi-walled carbon nanotubes,
carbon nanofibres and nanocomposites materials, TU Dresden
Junhee Han
Phase separation and structure formation in gadolinium based liquid and glassy metallic alloys,
TU Dresden
Julia Kristin Hufenbach
Entwicklung neuer Stahlgusslegierungen für den Werkzeugbau, TU Dresden
Alexander Kauffmann
Gefügeverfeinerung durch mechanische Zwillingsbildung in Kupfer und Kupfermischkristalllegierungen, TU Dresden
Sandra Kauffmann-Weiß
Verzerrte Fe-Pd-Schichten und deren magnetische Eigenschaften, TU Dresden
Mohsen Samadi Khoshkhoo
Nanostructure formation and thermal stability of Cu- and Cu-based alloys, TU Dresden
Stefanos Kourtis
Topological & conventional order of spinless fermions in 2D lattices, TU Dresden
Maria Krautz
Wege zur Optimierung magnetokalorischer Fe-basierter Legierungen mit NaZn13-Struktur
für die Kühlung bei Raumtemperatur, TU Dresden
Lars Kühn
Transportsysteme mit supraleitender Magnetlagertechnik unter Verwendung von massiven
Hochtemperatursupraleitern im Trag- und Führsystem, TU Dresden
Inge Lindemann
Synthese und Charakterisierung neuartiger, gemischter Tetrahydridoborate für die Wasserstoffspeicherung, TU Dresden
Susi Lindner
Charge transfer at phthalocyanine interfaces, TU Dresden
Tom Marr
Hochumgeformte Leichtmetallverbundwerkstoffe und deren festigkeitsbestimmende Faktoren,
TU Dresden
Sven Partzsch
Magnetoelectric Coupling Mechanisms in YMn2-xFexO5 and NdFe3(BO3)4 Revealed by Resonant
X-ray Diffraction, TU Dresden
Gregorzc Parzych
Transition metal borates as model electrode materials in Li-ion batteries, TU Dresden
Katja Pinkert
Mesoporöse Kohlenstoffmaterialien und Nanokomposite für die Anwendung in Superkondensatoren,
TU Dresden
Ummethala Raghunandan
Growth and field emission characteristics of MWCNT’s on different substrates, TU Dresden
Jan Romberg
Feinlagige und feinkristalline Titan/Aluminium-Verbundbleche, TU Dresden
Markus Schäpers
Exploring the Frustrated Spin-Chain Compound Linarite by NMR and Thermodynamic Investigations,
TU Dresden
Ronny Schlegel
Untersuchung der elektronischen Oberflächeneigenschaften des stöchiometrischen Supraleiters
LiFeAs mittels Rastertunnelmikroskopie und –spektroskopie, TU Dresden
Jan Trinckauf
An ARPES study of correlated electron materials on the verge of cooperative order, TU Dresden
Sascha Trommler
Einfluss von reversibler epitaktischer Verspannung auf die elektronischen Eigenschaften
supraleitender Dünnschichten, TU Dresden
PhD and diploma/master theses 107
Henning Turnow
Amorphe Metallschichten und ihre Verwendung als Mikroröhren, TU Dresden
Raghu Ummethala
Growth and field emission characteristics of MWCNTs on different substrates, TU Dresden
Jörn Venderbos
Integer and Fractional Quantum Hall effects in Lattice Magnets, Universiteit Leiden
Céline Vervacke
Sensing and Transport Properties of Hybrid Organic/inorganic Devices, TU Chemnitz
Silvia Vock
Resolving local magnetization structures by quantitative magnetic force microscopy, TU Dresden
Zhi Wang
High strength Al-Gd-Ni-Co alloys from amorphous precursors, TU Dresden
Ksenia Zhuravleva
Porous β-type Ti-Nb alloy for biomedical applications, TU Dresden
Martin Zier
Untersuchungen zum Einfluss von Elektrodenkennwerten auf die Performance kommerzieller
graphischer Anoden in Lithium-Ionen-Batterien, TU Dresden
Diploma and Mater Theses
Alexander Funk
Neuartige magnetokalorische Komposite: Herstellung, 3D-Struktur und magnetische
Charakterisierung, TU Dresden
Romy Schmidt
Elektrochemische Abscheidung von Hydroxylapatit auf Ti-Nb-Legierungen, TU Dresden
Tina Kirsten
Thermo-mechanische Behandlung der biomedizinischen Legierung Ti-40Nb zur Verbesserung der
mechanischen Eigenschaften, TU Dresden
Louise Klodt
Nanosheets Prepared by Pre-Sonication Assisted Liquid Exfoliation of Molybdenum Disulfide,
TU Dresden
Philipp Natzke
Microstructural analysis of Al-Cu Spray Deposits using Impulse Atomization, TU Dresden
Elisabeth Preuße
Synthese, Funktionalisierung und Charakterisierung von Eisenoxidnanopartikeln für biomedizinische
Anwendungen, TU Dresden
Martin Löbel
Verformungsverhalten mechanisch vorbehandelter amorpher Titanlegierungen, TU Dresden
Castro Nava Arturo
Development of novel radio-chemotherapy approaches using nanohybirds, TU Dresden
Herzig Melanie
Spektroskopie an organischen Ladungstransfer-Maerialien, TU Bergakademie Freiberg
Khomenko Vladislav
Nanoskalige Strukturerzeugung durch elektroneninduzierte Graphitisierung in diamantartigen
Kohlenstoffschichten, TU Bergakademie Freiberg
Kranz Ludwik
Transportmessungen an kleinen Eikristallen, TU Dresden
Kühne Tim
Spin-polarised scanning tunneling microscopy and spectroscopy on ultra-thin iron films, TU Dresden
Müller Eric
Spektroskopische Untersuchungen an dotierten Picen-Filmen, TU Dresden
Nohr Markus
Einkristallzucht und Charakterisierung von aromatischen Ladungstranfersalzen, HTW Dresden
Prateek Kumar Aharonov-Bohm Oscillations in a long-perimeter Bi2Te3 nanowire, TU Dresden
Christian Quandt
Entwicklung einer Anlage für magnetunterstütztes Tempern und Kristallisieren, HTW Dresden
Till Meißner
Konstruktion und Entwicklung eines Kryo-Magnetkraftmikroskops, HTW Dresden
Vignesh Mahalingham
Fabrication and investigations of vertically stocked quantum dot devices, TU Chemnitz
Michael Zopf
Coherent strain tunable single photon sources, TU Dresden
Hany Abushall
Double jet engines, TU Dresden
Robert Keil
Resonance fluorescence from GaAs/AIGaAs quantum dots, TU Dresden
Karsten Rost
Optimisation of an electrochemical etching approach for flexible Hall sensorics, TU Dresden
Anna Brunner
Untersuchungen zur Flussführung in nicht-orientiertem Elektroblech, TU Dresden
Christoph Konczak
Elektrochemische Präparation und Charakterisierung von FePd-Schichten für
Formgedächtnisanwendungen, TU Dresden
Dominik Markó
Tiefenempfindliche Kerr-Mikroskopie an fehlorientierten FeSi-Oberflächen, TU Dresden
Christian Becker
Untersuchung der dynamischen Oberflächen- und Volumenmagnetisierung weichmagnetischer Bänder,
TU Dresden
Stefan Richter
Einfluss uniaxialer Spannungen auf die Eigenschaften Fe-basierter Supraleiterschichten, TU Dresden
108 Calls and Awards
Calls and Awards
Calls on Professorships
Dr. Maria Daghofer
Univ. Stuttgart
Prof. Dr. Jürgen Eckert
Montan Univ. Leoben
Dr. Jochen Geck
Univ. Salzburg
Appointments as Adjunct, Honorary, Deputy and Associated Professorships
Prof. Dr. Jens Freudenberger
Bergakademie TU Freiberg (Deputy Professorship)
Awards
Prof. Dr. Manfred Hennecke
Bundesverdienstkreuz Erster Klasse
Prof. Dr. Oliver G. Schmidt
International Dresden Barkhausen Award
DGM Preis
Dr.-Ing. Alexander Kauffmann
DGM Nachwuchspreis 2014
Dr.-Ing. Alexander Kauffmann
Förderpreis 2014 des Deutschen Kupferinstituts
Dr. Saicharan Aswartham
DGKK-Nachwuchsforscherpreis 2014
Martin Grönke
VDI Nachwuchspreis
Josephine Zeisig
Poster Award des DGM Nachwuchsforums
IFW Awards
Dr. Alexey Popov
IFF Research Award 2014
Dr. Karin Leistner
IMW Research Award 2014
Dr. Lars Giebeler
IKM Research Award 2014
Dr. Fei Ding
IIN Research Award 2014
Dr. Tom Marr
Tschirnhaus-Medal of the IFW for excellent PhD theses
Dr. Jan Engelmann
Dr. Jan Trinkauf
Dr. Inge Lindemann
Dr. Alexander Kauffmann
Dr. Lars Kühn
Dr. Ronny Schlegel
Dr. Piter Gargarelle
Dr. Julia Hufenbach
Scientific conferences and IFW colloquia 109
Scientific conferences and IFW colloquia
Conferences
Feb. 16 – 20, 2014
Symposium “Magnetic Materials for Energy Applications IV” at TMS Annual Meeting 2014 in San Diego, USA
Feb. 25 – March 1, 2014
BioTiNet Winter school 2014, Vienna, Austria
March 27/28, 2014
Kick-Off Meeting of the SPP 1458 “High Temperature Superconductivity in Iron Pnictides”,
2 nd funding period, IFW Dresden
March 30 – Apr. 4, 2014
DPG-Frühjahrstagung der Sektion Kondensierte Materie (SKM) Dresden
May 4 – 8, 2014
IEEE International Magnetics Conference (Intermag), Dresden
May 5, 2014
Symposium “Energy assisted magnetic recording beyond 1TB/ in2” at the INTERMAG 2014 conference,
Dresden
July 17 – 18, 2014
Workshop “NMR, μSR, Mössbauer spectroscopies in the study of Fe-based and other unconventional
high-Tc superconductors”, IFW Dresden
Sept. 12/13, 2014
Final IRON-SEA meeting, IFW Dresden
Nov. 5 – 8, 2014
BioTiNet Final Meeting, Dresden
IFW Colloquium
30.01.2014
Prof. Dr. Rudolf Schäfer, IFW Dresden, IEEE Distinguished Lecturer,
Magneto-Optic Analysis of Magnetic Microstructures
27.03.2014
Prof. Dr. Peter Hirschfeld, University of Florida, Department of Physics, Fe-based Superconductors:
What have we learned?
24.04.2014
Dr. Jack J.W.A. van Loon, DESC - Dutch Experiment Support Center, Amsterdam,
The Human Hypergravity Habitat, H3 - A ground based facility for Space Explorations and
General Human Health Research in Ageing and Obesity
15.05.2014
Prof. Dr. J.M.D. Coey Trinity College, Dublin, Ireland, Gas bubbles in electrolysis.
How could magnetic fields help?
110
Guests and Scholarships
Guests and Scholarships
Guest scientists (stay of 4 weeks and more)
Name
Home Institute
Home country
Afrassa, Mesfin Asfaw
Dr. Arayanarakool, Rerngchai
Arshad, Muhammad Shahid
Asgharzadeh Javid, Fatemeh
Bogdanov, Nikolay
Dr. Bonatto Minella, Christian
Castro Nava, Arturo
Cho, Dai-Ning
Dr. Cirillo, Giuseppe
Dr. Daghofer, Maria
Delmonde, Marcelo
Dr. Dey, Tusharkanti
Enachi, Mihai
Fedorov, Alexander
Prof. Dr. Garifullin, Ilgiz
Ghunaim, Rasha
Dr. Grüneis, Alexander
Guix Noguera, Maria
Günes, Taylan
Addis Ababa Univ. Ethiopia
BIOS, Institute of Nanotechnology Twente
Jozef Stefan Institute, Slovenia
Material and energy research center Karaj
NUST MISiS Moscow
Helmholtz-Zentrum Geesthacht
National Autonomous Univ. of Mexico
National Central Univ. Taiwan
Univ. of Calabria
Univ. Stuttgart
Univ. of Sao Paulo
Indian Institute of Technology Bombay
Technical Univ. of Moldova
St. Petersburg State Univ.
Zavoisky Physical-Technical Inst., Kazan
Univ. of Jordan
Univ. Vienna
Catalan Institute of Nanotechnology (ICN)
Yalova Univ.
Ethopia
Thailand
Pakistan
Iran
Russia
Italy
Mexico
China
Italy
Austria
Brasilia
India
Rep. of Moldova
Russia
Russia
Palestina
Austria
Spain
Turkey
Guo, Er-Jia
Gürsul, Mehmet
Dr. Harnagea, Luminita
Hassan, Abdelwahab Hamdy
Prof. Dr. Hirschfeld, Peter J.
Dr. Jiang, Chongyun
Dr. Jung, Hyoyun
Dr. Jung, Kyubong
Dr. Kataeva, Olga
Khim, Seunghyun
Kim, Jinyoung
Dr. Kim, Beom Hyun
Dr. Kim, Hee Dae
Kirsanske, Gabija
Kravchuk, Volodymyr
Kulesh, Nikita
Dr. Kumar, Sanjeev
Dr. Leksin, Pavel
Levchenko, Evgeny
Dr. Liu, Xianghong
Machata, Peter
Makharza, Sami A M
Dr. Mandarino, Angelo
Dr. Manna, Anamika
Dr. Manna, Kaustuv
Matczak, Michael
Medina Sanchez, Mariana
Miao, Jing
Mityashkin, Oleg
MLU Halle-Wittenberg
Cukurova Univ.
Univ. Paris
Fayoum University Egypt
Univ. of Florida
Institute of Semiconductors, Bejing
Yonsei Univ.
Univ. of Tokyo
A.E. Arbuzov Institute, Kazan
Seoul National Univ.
Univ. of Technology Lulea, Sweden
Pohang Univ. of Science and Technology
Univ. of Oxford
Univ. of Copenhagen
Bogolyubov Inst. for Theoretical Physics Kiev
Ural Federal Univ. Yekaterinburg
Iiser Mohali Faculty of Physics
Kazan Physical Technical Institute
Tomsk Polytechnic Univ.
Nankai Uni
Slovak Univ. of Technology, Bratislava
Al-Quds Univ.
Instituto C. Elio Vittorini
Jadavpur Univ.
Indian Institute of Science
Institute of Molecular Physics PAS
Univ. Autonoma de Barcelona
Edith Cowan Uni.
Kazan State Univ.
China
Turkey
Romania
Egypt
USA
China
South Korea
South Korea
Russia
South Korea
South Korea
China
South Korea
Lithuania
Ukraine
Russia
India
Russia
Russia
China
Slovakia
Palestina
Italy
India
India
Poland
Columbia
China
Russia
Guests and Scholarships 111
Mohan, Ashwin
Mondin, Giovanni
Dr. Moravkova, Zuzana
Moscoso Londono, Oscar
Prof. Dr. Nicoara, Mircea
Niyomsoan, Saisamorn
Okulov, Ilya
Oliveira, Roberto
Pal, Santosh Kumar
Plotnikova, Ekaterina
Dr. Reja, Sahinur
Dr. Romhanyi, Judit
Saei Ghareh Naz, Ehsan
Salman, Omar Oday
Dr. Singh, Shiv Jee
Dr. Smirnova, Elena
Tosa, Dacian Ioan
Dr. Ummethala, R. Nandan
Dr. Vavilova, Evgeniia
Dr. Vavilova, Evgeniia
Venderbos, Jörn
Xu, Lei
Yadav, Ravi
Dr. Yakhvarov, Dmitry
Prof. Yokoyama, Yoshihiko
Zhang, Jiaxiang
Dr. Zhang, Yang
Tata Institute of fundamental research
Univ. Padua
Institute of Macromolecular Chemistry
Univ. des Buenos Aires
Politehnica Univ. Timisoara
Burapha Univ.
Ural State Technical Univ. Ekaterinburg
UFRJ, Rio de Janeiro
Indian Institute of Technology Delhi
Prokhorov General Physics Institute
Univ. of Cambridge
Eötvös Univ. Budapest
Urmia Univ.
Dijlah Uni. Baghdad
Univ. Tokio
A.F. Ioffe Phys.-Techn. Institut
Politehnica Univ. Timisoara
Indian Inst. of Technology Kanpur
Zavoisky Physical-Technical Inst. Kazan
Zavoisky Physical-Technical Inst. Kazan
Foundation for Fund. Research on Matter
FZ Jülich
Indian Inst. of Sc. Education & Research Mohali
Inst. of Organic and Physical Chemistry Kazan
IMR Thoku Univ. Japan
Peking Univ.
The Hong Kong Polytechnic Univ.
India
Italy
Czech Rep.
Columbia
Romania
Thailand
Russia
Brasilia
India
Russia
India
Hungary
Iran
Irak
India
Russia
Romania
India
Russia
Russia
Netherlands
China
India
Russia
Japan
China
China
Scholarships
Name
Home country
Donor
Afrassa, Mesfin Asfaw
Dr. Zhang, Yang
Dr. Dassonneville, Bastien
Dr. Prando, Giacomo
Dr. Jorgensen, Matthew
Martins dos Santos, Jonadabe
Neves, Andre Martins
Romero da Silva, Murillo
Miyakoshi, Shohei
Cao, Jing
Li, Gonjin
Li, Shilong
Lu, Xueyi
Ma, Pan
Pang, Jinbo
Shi, Zhi Xiang
Sun, Xiaolei
Wang, Pei
Dr. Wang, Jiao
Xi, Lixia
Yin, Yin
Ethopien
China
France
Italy
USA
Brasil
Brasil
Brasil
Japan
China
China
China
China
China
China
China
China
China
China
China
China
Addis Ababa Univ., Ethopien
AvH Foundation
AvH Foundation
AvH Foundation
AvH Foundation
CAPES Foundation Brasil
Chiba University’s SEEDS Foundation
China Scholarship Council
112 Guests and Scholarships
Yuan, Xueyong
Yuan, Feifei
Zhang, Long
Zhang, Jiaxiang
Zhang, Panpan
Salazar Enriquez, Christian David
Madian, Mahmoud
Chakraborty, Abhra
Chatterjee, Riddhi Pratim
Harihara Subramonia, Anand
Kolay, Santa
Dr. Kumar, Sarvesh
Prof. Dr. Mukhopadhyay, N. Krishna
Natarajan, Harshavardhana
Pal, Santosh Kumar
Dr. Singh, Shiv Jee
Shahid, Rub Nawaz
Makharza, Sami A M
Kamashev, Andrei
Gargarella, Piter
Kavetskyy, Taras
Loftin, Christian
Dr. Krupskaya, Yulia
Sander, Jan
Attar, Hooyar
Mangalore, Deepthi Kamath
Vijay Karnad, Gurucharan
Niyomsoan, Saisamorn
Dr. Brehm, Moritz
Iakovleva, Margarita
Liu, Bo
Jia, Yandong
Cetner, Tomasz
Takahashi, Yasuhiro
Dr. Nenkov, Konstantin
Dr. Kim, Beom Hyun
Dr. Chang, Ching-Hao
Surrey, Alexander
Ryu, Wook Ha
China
China
China
China
China
Columbia
Egypt
India
India
India
India
India
India
India
India
India
Pakistan
Palestina
Russia
Spain
Ukraine
USA
Russia
Germany
Iran, Islam. Rep.
India
India
Thailand
Austria
Russia
China
China
Polen
Japan
Germany
China
China
Germany
South Korea
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DAAD
DFG
ECEMP
Edith Cowan University, Australia
ERASMUS MUNDUS
ERASMUS MUNDUS
ERASMUS MUNDUS
Erwin Schrödinger Scholarship
Government of Rep. Tatarstan
Graduiertenkolleg TU Chemnitz
Harbin Institute of Technology, China
High Pressure Physics, PAS
Jasso Support Program
ML University Halle-Wittenberg
National Research Foundation of Korea
National Science Council, China
Reiner Lemoine Foundation
Soul National Univ.
Guest stays of IFW members at other institutes 113
Guest stays of IFW members at other institutes
Oliver Schmidt
27.10. – 05.11.2014, Shanghai/China – Kooperation Fudan Univ.
Micheal Melzer
1.11. – 10.11.2014, Honolulu/Hawaii/USA – MMM Conference
Yongheng Huo
28.10. – 08.11.2014 Heifei/China – Cooperation with Univ. of Science
and Technology China
Denys Makarov
15.03. – 29.03.2014 Valpraíso/Chile – Universidad Technica Frederico
Santa Maria Departmento de Física
Robert Streubel
10.03. – 26.03.2014 Berkeley/USA – Advanced Light Source Lawrence
Berkeley National Laboratory, Measuring time
Vladimir Fomin
03.03. – 16.03.2014 Riverside/USA –Research Cooperation UC Riverside
Matthew Jorgensen
03.04. – 15.04.2014 Utah/USA – Research Cooperation University
of Utah
Stefan Hameister
26.09. – 03.10.2014, Saarbrücken, Highlights der Physik,
Michael Hering
26.09. – 03.10.2014, Saarbrücken, Highlights der Physik
Ivan Soldatov
14.02. – 24.02.2014, Jekaterinburg/Russland,
International Winterschool on Physics,
Tilo Espenhahn
13.01. – 23.03.2014, Univ.Niigata/Japan, Students‘ exchange
Fritz Kurth
01.05. – 11.05.2014, NHMFL, Tallahassee/USA, measurements
Tilo Espenhahn
28.09. – 08.11.2014, Rio de Janeiro/Brasilien, PPP Probral,
Univ. exchange program
Anne Berger
Lars Kühn
Prof. Rudolf Schäfer
01.10. – 12.10.2014, Oak Ridge National Lab, Detroit/USA,
invited talks and lectures
Jens Hänisch
13.12. – 20.12.2014, LANL, Los Alamos/USA, measurements
Vamshi Mohan Katukuri
03. – 09.01.2014, International Centre for Theoretical Sciences,
Bangalore India, Winter school on „Strongly correlated systems
From models to materials“
Stefanos Kourtis
19.03. – 22.04.2014, Boston University, Collaboration on
three-dimensional topologically ordered states
Stefanos Kourtis
23.04. – 06.05.2014, University of Leeds, Great Britain,
Studies on Majorana-fermion lattices in three dimensions
Ekaterina Plotnikova
05. – 28.08.2014, Ecole de Physic de Houches, Summer School:
Topological aspects of condensed matter physics
Judit Romhányi
15.09. – 17.10.2014, Budapest University of Technology and Economics,
Department of Physics, Scientific collaboration
Carmine Ortix
03. – 26.11.2014 University of Utrecht, Collaboration on theory of
graphene nanostructures
Jeroen van den Brink
26.10. – 20.11.2014 University of California, Santa Barbara,
Workshop „Iron pnictides and beyond“ at Kavli-Institute for Theoretical
Physics (KITP) and research visit
Ekaterina Plotnikova
28.10. – 21.11.2014 University of California, Santa Barbara,
Workshop „Iron pnictides and beyond“ at Kavli-Institute for Theoretical
Physics (KITP) and research visit
Cristina Gonzalez Gago
13.09. – 29.09.2014, University of Oviedo, Spain, training course and
GD-ToF-MS measurements
Lixia Xi
16.06. – 06.07.2014, Foundry Research Institute Krakau, Poland,
DAAD-PPP
Lixia Xi
15.11. – 24.12.2014, Foundry Research Institute Krakau, Poland,
DAAD-PPP
Junhee Han
29.08. – 13.09.2014, Yonsei University Seoul, Korea
114 Guest stays of IFW members at other institutes
Mariana Calin
03.04. – 26.04.2014, Univ. Politehnica Timisoara & Univ. Politehnica
Bucuresti, Timisoara/Bukarest Romania, Teaching and Research
activities
Bönisch Mathias
25.02. – 14.03.2014, Faculty for Physics, Vienna, Austria
Bastien Dassonneville
04.08. – 29.08.2014, École de Physic Les Houches, France,
Summer School
Deng Qingming
08.01.2013 – 10.06.2014, Nagoya Univ. Japan, Research cooperation
on the formation mechanism of endohedral metallofullerenes
Alexander Fedorov
09.01. – 24.01.2014, Elettra Sincrotrone Trieste, Italy, Measurements
Alexander Fedorov
09.03. – 24.03.2014, Bessy Berlin, Measurements
Grafe Hans-Joachim
14.03. – 16.05.2014, Univ. of California, Davis, California, USA,
Research stay
Sirko Kamusella
01.06. – 22.07.2014, Paul Scherrer Institut Villigen, Switzerland,
Measurements at SwissMuonSource
Wolf Schottenhamel
26.01. – 16.02.2014, Brookhaven National Laboratory,
New York, USA, Measurements
Yulia Krupskaya
01.07.2013 – 30.06.2015, DPMC University of Geneva, Switzerland
Zhonghao Liu
01.10.2013 – 31.08.2014, HZB Berlin at Bessy II, measurements
Board of Trustees, Scientific Advisory Board
Board of trustees
Jörg Geiger, Saxonian Ministry of Science and Art
- Head -
Dr. Herbert Zeisel, Federal Ministry of Education and Research
Prof. Dr. Gerhard Rödel, TU Dresden
Prof. Dr. Konrad Samwer, Univ. Göttingen
Scientific Advisory Board
Prof. Dr. Maria-Roser Valenti, Univ. Frankfurt, Germany
Prof. Dr. Philippe M. Fauchet, Vanderbilt Univ., USA
Prof. Dr. Matthias Göken, Univ. Erlangen-Nürnberg, Germany
Prof. Dr. Alan Lindsay Greer, Univ. of Cambridge, U.K.
Prof. Dr. Rudolf Gross, Walter Meißner Institute Garching, Germany
Prof. Dr. Rolf Hellinger, Siemens AG Erlangen, Germany
Prof. Dr. Xavier Obradors Berenguer, Univ. Autònoma de Barcelona, Spain
Prof. Dr. Roberta Sessoli, Univ. di Firenze, Italy
Prof. Dr. Eberhardt Umbach, Karlsruhe Institute of Technology, Germany
- Head -
115
Institute for
Solid State Research (IFF)
Prof. Dr. Bernd Büchner
Secr.: Kerstin Höllerer
Manja Maluck
- 808
- 300
- 805
- 544
Dr. Heike Schlörb (temp.)
- 566
Dr. Jens Freudenberger
Synthesis and crystal growth
Superconducting Materials
Dr. Sabine Wurmehl
Dr. Ruben Hühne (temp.)
- 519
Transport and scanning probe
microscopy
Magnetic Microstructures
Dr. Christian Heß
Prof. Dr. Rudolf Schäfer
- 533
- 328
- 278
Nanoscale chemistry
Dr. Alexey Popov
Dr. Bernd Rellinghaus
Prof. Dr. Ludwig Schultz
Institute for Theoretical
Solid State Physics (ITF)
Secr.: Brit Präßler-Wüstling - 217
Johanna Riedel
- 198
Prof. Dr. Prof. h. c.
Oliver G. Schmidt
Secr.: Ulrike Steere
Ref.: Anja Schanze
Prof. Dr.
Secr.: Grit Rötzer
Micro- and Nanostructures
Magnetic Nanomembranes
Numerical Solid State Physics
ERC-Group
“Shapeable Magnetoelectronics”
Dr. Manuel Richter
Dr. Thomas Gemming
- 602
- 298
Solidification Processes and
Complex Structures
- 550
Dr. Mihai Stoica
- 716
Dr. Anja Waske
- 754
- 101
- 846
Dr. Annett Gebert
Quantum Chemistry
- 1829
Quantum theory of complex
nanoarchitectures
- 1152
- 275
Dr. Fei Ding
Dr. Carmine Ortix
- 352
- 752
Materials for Energy Applications
Integration of Material and
Living Matter on the Nanoscale
Dr. Lars Giebeler
Dr. Anne-Karen Meyer
- 652
Alloy Design and Processing
Location Chemnitz
Smart Systems Campus
Dr. Uta Kühn
Oliver G. Schmidt
Dr. Simon Pauly
- 360
- 648
Dr. Liviu Hozoi
Dr. Matthew Jorgensen
- 400
- 380
Integrated Nanonphotonics
- 402
Metallic Glasses and Composites
- 871
Dr. Denys Makarov
Rolled-up Photonics
Chemistry of
Functional Materials
- 223
- 800
- 810
- 845
- 644
Magnetic Composites and
Applications
Location Niedersedlitz
Info Center SupraTrans
Surface dynamics
Dr. Hagen Schmidt
- 230
Metastable and
Nanostructured Materials
Magnetic properties
Dr. Vladislav Kataev
- 102
Metal Physics
Synchrotron methods
Dr. Sergey Borisenko
- 223
Magnetism and
Superconductivity
Electron spectroscopy and
microscopy
Prof. Dr. Martin Knupfer
Prof. Dr. Rudolf Schäfer
(temp.)
Secr.: Svea Fleischer
Institute for
Integrative Nanosciences (IIN)
Institute for
Complex Materials (IKM)
Institute for
Metallic Materials (IMW)
- 218
- 800
- 451
Date: 01/2015
116 Research organization of IFW Dresden
Research organization of IFW Dresden
Executive Board
PF 27 01 16
D-01171 Dresden
Prof. Dr. Manfred Hennecke, Scientific Director
Hon.-Prof. Dr. h. c. Rolf Pfrengle, Administrative Director
Publisher:
Leibniz Institute for Solid State and Materials Research Dresden
Mail address
Helmholtzstrasse 20
D-01069 Dresden
+49(0)351 4659 540
Visitors address
Fax
http://www.ifw-dresden.de
+49(0)351 4659 0
Internet
[email protected]
Phone
e-mail
Leibniz Institute for Solid State and Materials Research Dresden
General Meeting
Scientific Advisory Board
Board of Trustees
Head: Prof. Dr. Maria-Roser Valenti, J.-W. Goethe-Univ. Frankfurt
Head: MDgt Jörg Geiger
Executive Board
Scientific-Technical Council
Head:
Dr. Hagen Schmidt
-278
Ass.: Dr. Carola Langer
Secr.: Katja Clausnitzer
-234
-100
Institute for
Metallic Materials
Institute for
Solid State Research
Prof. Dr.
Bernd Büchner
-808
Secr.: Kerstin Höllerer
Manja Maluck
-300
-805
Prof. Dr.
Rudolf Schäfer (temp.)
-223
Secr.: Svea Fleischer
-102
Dr. Carola Langer -234
-800
Secr.: Brit Präßler-Wüstling -217
Johanna Riedel
-198
Ass.: Anja Schanze
Secr.: Ulrike Steere
-845
-810
Phone
Tel.: +49 351 46 59-0
Fax: +49 351 46 59-540
Project Funding, EU-office
(FF)
Dipl.-Ing. Ök. MB (TU)
Birgit Benz
-770
Prof. Dr.
-400
Secr.: Grit Rötzer
-380
Confidential Representative
(Ombudsperson)
Representative Body for
Disabled Employees
Youth and Trainee
Representative Council
Prof. Dr. R. Schäfer
Dr. Hartmut Siegel
Marco Wittig
-223
Internet
www.ifw-dresden.de
[email protected]
-507
Knowledge and
Technology Transfer
(WTT)
Dr. Uwe Siegel - 424
Institute for Theoretical
Solid State Physics
Oliver G. Schmidt
Head of task group work-life-balance:
Gelia Preuß
-583
Mailing Address
PF 27 01 16
D-01171 Dresden
Public Relation, Media
(PR)
-602
Prof. Dr.
Jürgen Eckert
Contact
Visitor’s Address
Helmholtzstrasse 20
D-01069 Dresden
Support Staff
Institute for
Integrative Nanosciences
Institute for
Complex Materials
Equal Opportunity Commissioner
-306
Administrative Director
Hon.-Prof. Dr. h. c. / TU Bratislava
Rolf Pfrengle
Ass.: Katja Backhaus-Nousch -160
Secr.: Anja Hänig
-200
Patent
Patent Agents
Rauschenbach
tel.: 0351 475 99 90
Internal Auditor
(IR)
Dipl.-Betriebsw. (FH)
Stefan Leipnitz -876
-359
Research Technology Division
Administrative Division
Prof. Dr.
Dirk Lindackers
Dipl.-Kffr.
Friederike Jaeger
-580
- 620
Secr.: Nicole Büttner
-505
71 Electrical Engineering
and Electronics
Dipl.-Ing. (FH)
-509
Karsten Peukert
72 Mechanical Engineering
Secr.: Ulrike Nitzold -621
81 Finance Deparment
Dr. Ralf Voigtländer
Dipl.-Ing.-Ök.
Klaus-Dieter Faulian
-121
Dipl.-Phil.
Martina Schmidt
-457
82 Human Resources
-578
73 Information Technologies
83 Purchase and Disposal
Dr. Herbert Zimmermann -345
Marion Hauptmann
(temp.)
-254
84 Information and
Documentation
Dipl.-Bibl.
Nadja Röder
-366
85 Facility Management
- 130
Company Medical
Officer
Dr. Dieter Jährig
tel.: 03591 326 630
Safety Officer
(SI)
M. Sc.
Andrej Kraus
Data Security Officer
Ing. Werner Effenberg -201
Dr. Ralph Wagner
tel.: 0351 810 31 50
Date:12/2014
Organization chart of the IFW Dresden
Labour Council
Head:
Marek Ulbrich
Scientific Director
Prof. Dr. Manfred Hennecke

IFW_Jahres14_04.02_Layout 1

Transcription

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