Annotated Presentation, PDF

Transcription

IEEE/CSC & ESAS SUPERCONDUCTIVITY NEWS FORUM (global edition), October 2015.
Plenary presentation PL10 given at EUCAS 2015; Lyon, France, September 6 – 10, 2015.
Not submitted to IEEE Trans. Appl. Supercond.
Marina Putti
University of Genova and CNR-SPIN
UNIVERSITÀ
DEGLI STUDI
DI GENOVA
1
H3 S
TC=203 K
P>1.5 GPa
Ermets’s group
2
MgB2
H3S
TC=203 K
P>1.5 GPa
Iron-based
supercoductors
TC(max)=58 K
Ermets’s group
3
Strong covalent bonds between
the boron atoms.
Coupling of electron with the
optical vibration mode of boron
atoms (mode E2g).
Tc = 39 K, close to the
maximum value predicted
by BCS theory
4
∆π(0) ∼ 2 meV ; ∆σ(0) ∼ 7 meV
5
Hole-π
σ bands
π bands
2D
3D
hole-like
nearly electron-like
strongly coupled with
E2g mode
weakly coupled with E2g
mode
Different parity
Interband scattering is negligible
σ−orbitals
electron-π
hole-σ
hole-σ
Type II
Type I
Tc is amplified (by a factor 2) by the occurnce of two
decoupled bands
6
In a two-band s/c interband scattering mixes strong σ-pairs with
weak π-pairs and causes pair breaking.
A.A.Golubov and I.I.Mazin, PRB 55 (1977)
∆σ
19-25 K
increasing disorder
𝟐𝟐∆(𝟎𝟎)
=3.56
𝒌𝒌𝑻𝑻𝒄𝒄
∆π
increasing disorder
O.V. Dolgov et al. PRB 72, 024504 (2005)
7
 C in the B site: Mg(B1-yCy)2
 Al in the Mg site: Mg1-xAlxB2
 Neutron irradiation
 α-particle irradiation
Wang et al
Gandikota et al
Gandikota et al
Ferrando et al
Tarantini et al
Tc (K)
40
30
J. Kortus et al.
20
Tc  0
10
0
0
20
40
60
80
ρ0,g (µΩcm)
Putti et al SUST 21 (2008) 043001
Electron doping
emptying of the σ−bands
Interband scattering
 merging of the gaps
Intraband scattering
 smearing of the DOSs
8
Clean Single crystal
Disordered
thin film
Gurevich’s
two band model
Lyard et al., PRB 66, 180502(R) 2002
A. Gurevich Physica C 456 (2007) 160–169
16
14
µ0Hc2 [T]
12
C-doped
C-doped
irradiated
irradiated
dirty limit
clean limit
10
8
6
4
2
undoped
Al-doped
Al-doped
0
0.0
0.2
0.4
0.6
0.8
1.0
T/T
9
Al
C
Tc , Kelvin
10
Ab-initio model predicts :
𝜇𝜇0 𝐻𝐻𝑐𝑐𝑐 ∥ 𝑎𝑎𝑎𝑎 ~ 80𝑇𝑇
𝜇𝜇0 𝐻𝐻𝑐𝑐𝑐 ∥ 𝑐𝑐 ~ 30𝑇𝑇
In extremely dirty π bands
 smearing of π-DOS does not affect Tc
𝑯𝑯 ∥ 𝐚𝐚𝐚𝐚
Dirty σ−bands
𝑯𝑯 ∥ 𝐜𝐜
Dirty π−bands
Brotto et al., PRB 82, 134512 (2010)
11
RRR~30
Chen J, PRB 74 174511 (2006)
Thin films produced by hybrid
physical–chemical vapor deposition
(HPCVD) (X X Xi group)
 Extremely clean (𝜌𝜌0 < 1 𝜇𝜇Ω𝑐𝑐𝑐𝑐)
 Enhanced Tc (𝑇𝑇𝑐𝑐 > 40 𝐾𝐾)
 Huge Jc(0) (~108 𝐴𝐴/𝑐𝑐𝑐𝑐2 )
 C-doping substantially improves
𝐽𝐽𝑐𝑐 (𝐻𝐻)
12
Electron Beam evaporation
Kitaguchi et a l APL 85, 2842 (2004)
Nanometer-sized columnar-grain
structure can produce 𝐽𝐽𝑐𝑐 (B) exeeding
106 A/cm2
PLD + post-annealing process
A. Matsumoto: APEX 1, 021702 (2008)
Jc enhancements in fields up to 26
T above Nb3Sn performance in
nanostractured thin films
In thin films Jc is enhanced by grain boundary pinning
13
High Tc, Bc2 and Jc
No evidence of “weak link”
D.C.Larbalestier et al., Nature 410, 186 (2001)
Coherence length
ξ~ 10 nm
G.Grasso et .al. 2001 APL 72, number 9
14
Courtesy of M. Eisterer
Current Percolation and Bc2 Anisotropy.
Eisterer, et al.,PRL 90,247002 2003
Jc(B) is function
of the Bc2
anisotropy
Bc 2 (θ ) =
γ =
Bc||2
γ 2 cos(θ ) 2 + sin(θ ) 2
Bc||2
~ 5 − 6 (clean limit)
Bc⊥2
λ anisotropy and pairbreaking effects
Polyanskii et al., PRB 90, 214509 (2014)
Jc(B=0) is function of the
λ anisotropy
c
σ-pairs
π−pairs
a
b
15
Incresing Hc2 with C doping
Introducing pinning centers with nanoparticle addiction
F / FPmax
Carbon in elemental form (microspheres, nanotubes, nanodiamond, graphene)
C-containing compounds such as SiC, TiC, B4C,
Organic compounds: -malic acid , toluene, benzene, naphthalene , thiophene, pyrene
1.0
not milled
0.8
increasing
milling time
0.6
0.4
0.2
grain boundary
pinning force
0.0
0.0
0.2
0.4
0.6
(a)
0.8
1.0
V Braccini, INFM, Italy
E W Collings, The Ohio State University, US
S X Dou, University of University of Wollongong, Australia
R Flukiger, DPMC, University of Geneve; Switzerland
W Goldaker, KIT, Germany
H Kumakura, NIMS, Japan
Y Ma, et al Chinese Academy of Sciences, China
……
H / Hirr
16
2015
2007
IMD
coroneneadded
added
C-nanotube
AIMI
added
SiCCadded
IMD
SiC added
C-doped+HIP
C-doped+milling
C-doped+HIP
thin film
H//film
66
10
Jc (A/cm2)
5
105
4
104 Columbus tape
(Courtesy of P.Kovac)
33
10
C-doped
stearic acid added
added
malicPIT
acidSiC
added
PIT
malic
B4C+SiC addedacid added
2
102
1
101
thin film
H//film
Moving from 1stG (PIT ) to 2° G
(IMD ) wires
(Giunchi G, et.al 2003 SUST 16 285)
PIT
a) Before reaction
Fe
IMD
Mg
commercial tape
0
5
10
15
B (T)
K Togano, et al., SUST 22 (2009) 015003
J.H. Kim , et al., SUST 23 (2010) 075014
G Z Li et al.SUST 26 (2013) 095007
Shu Jun Ye, et al., SUST 27 (2014) 085012
20
25
30
After reaction
hole
Courtesy: H. Kumakura, NIMS
MgB2
M. Putti and G.Grasso MRS BULLETIN 36 , 608
17
1G ( PIT))
18
Ready for industrial production
2 different manufacturing process
ex-situ and in-situ technique
Interested in commercial production
of wires or wires+magnet
Early stage New York based company,
granted as SME partner by UK for R&D activities on MgB2
They plan to start commercial production in early 2014.
MgB2 wires for Cryo-free MRI
Summer 2015 for MRI magnet 1.5T-3T magnet
Interested in the MgB2 technology
Bruker BEST
1000 m of MgB2 wire
already demonstrated
in collaboration with IFW Dresden
Patents on MgB2 wires
Several R&D activities
Courtesy of
19
First commercial
systems using
MgB2
installed in
hospital in EU
and North
America
Operating T=20K
26 magnet systems produced so far
Courtesy of
20
58 K
2014
100 K
FeSe
Single layer
21
112 type (CaFeAs2)
Intercalated FeSe-11
122 ( KFe2Se2)
22
LaFeAsO1-xFx
F
O
RE
Fe
As
LaFeAsO1-xFx
23
FeTe
FeSe
24
Q
D. J. Singh and M.-H. Du: Phys. Rev. Lett. 100 (2008)
Igor I. Mazin, Nature 464 (2011) 183
Superconducting order parameter:
 MgB2 : two-band s wave with the same sign
 IBS : two-band s± wave
MgB2
IBS
25
T Katase et al., PRB 85, 140516(R) (2012)
1.0
S Onari eta l., PRL 103, 177001 (2009)]
Superconductivity in IBS is
quite robust agains disorder
0.8
Tc/Tc0
In case of s ± wave pairing a rapid
suppression of Tc with impurities
has been predicted
MgB2
V3Si
Nd-1111
0.6
0.4
YBCO
0.2
0.0
0.1
1
10
g=Γ/2πkBTc0
C Tarantini et al.,PRL 104, 087002 (2010)
26
11
1111
Fe(TeSe)
Ba(FeCo)2As2
NdFeAs(OF)
60
H//ab
H//c
50
µ0Hc2 [T]
40
30
20
10
0
30
35
40
T [K]
Slope -15 T/K
Anisotropy is 5
45
50
8
12
16
T [K]
Slope -4.9 T/K
Anisotropy is 2-1.5
20
0
5
10
15
20
T[K]
Slope -50 T/K
Anisotropy 3-1
Putti et al. SUST 23 034003 (2010)
27
11
1111
C. Tarantini et al., PRB 84, 184522 (2011)
28
1111
122
11
YBCO
MgB2
Tc [K]
55
38
16
93
39
Bc2 (0) [T]
>50
60
55
>50
20-30
ξab [nm]
2.5
3
1.5
2.2
10
γΗ
5
2
2-3
4-14
3-5
λab (nm)
200
200
490
180
50-100
Ginzburg number Gi
4·10-4
2·10-5
1·10-3
>10-3
<10-5
pairing
Not BCS Not BCS Not BCS Not BCS
BCS
Several similarities with HTS :
High Hc2, small coherence length, unconventional pairing
but, lower anisotropy
29
107
11 (Braccini et al.)
1111 (Iida et al.)
122 P doped (Sato et al.)
122 Co doped (Tarantini et al.)
Jc [A/cm2]
106
105
Filled symbols: H//ab
Empty symbols: H//c
104
0
5
10
15
20
µ0H [T]
25
30
V. Braccini, APL 103, 172601 (2013)
Iida , Sci. Rep. 3:2139 (2013)
Tarantini et al., Sci. Rep. 4, (2014).
Sato et al., Applied Physics Letters 104, 182603 (2014);
30
1000
YBCO 2G H//c
400 GN/m3
Fp , GN/m3
100
10
NbSn3
Filled symbols: H//ab
Empty symbols: H//c
1
0
10
20
30
Nd-1111 (Kurth et al.)
Sm-1111 (Iida et al.)
122 (Tarantini et al.)
11 (Si et al.)
40
50
B , Tesla
Kurth et al., EUCAS 2015
Iida , Sci. Rep. 3:2139 (2013)
Tarantini et al., Sci. Rep. 4, (2014).
Sato et al., Applied Physics Letters 104, 182603 (2014)
Si, W. et al. Nat. Commun. 4:1347 (2013).
31
P doped 122
(Ikuta et al. 2013)
JGB (A/cm2)
107
106
Co doped 122
YBCO
YBCO(Katase et al.2011)
105 11 (Si et al. 2015)
11 (Kawale et al. 2014)
Co doped 122
(Lee et al. 2009)
104
0
10
20
30
Lee et al., Appl. Phys. Lett. 95, 212505 (2009).
Katase et al., Nat. Commun. 2, 409 (2011)
Sagakami et al.,Physica C 494 (2013) 181–184
40
Θ (°)
Kawale et al.,ASC 2014
Si et al, Appl. Phys. Lett. 106 032602 (2015)
In HTS Jc decreases exponentially with GB angle
IBS Advantageous GB over HTS
32
107
106
T= 4.2K
self-field
Jc (A/cm2)
105
104
103
102
1111
122
11
101
Improving the phase
purity
Controlling the
mechanical processes
Incresing the density
by HP
2009 2010 2011 2012 2013 2014 2015
Year
I.Pallecchi et al, SUST (2015) 28
33
2015
 1.4x105A/cm2
NIMS
Y. Ma, Physica C 516 (2015) 17-26
34
IBAD-MgO (TIT)
SS/AgSn double sheath (NIMS)
Hot pressing (CAS)
6
Jc [A/cm2]
10
Jc anisotropy
5
10
Nb3Sn
104
Nb-Ti
Lin et al., Sci. Rep. 4 (2014) 6944
Gao et al., EUCAS 2015
Katase et al., APL 98, 242510 (2011)
103
Awaji EUCAS2015
0
MgB2
10
µ0H [T]
Effect of strain
20
Courtesy: Y.Ma CAS
Marina Putti, EUCAS 2015
35
36
Always Hydrogen has been the best candidate for room temperature superconductivity but
it need extremely high pressure to become metallic.
1) Improvment of diamond anvil cells (DAC) which today allows to reach
600 Gpa exceeding the pressure in the Earth's inner core (360 GPa).
Several new elements superconducting under pressure discovered in the
last 15 years: Sulfur (17 K), Oxygen 0.6 K) , Iron (1.2 K) , Boron (11 K),
Lithium (20 K), Europium (2.5 K).
Dense hydrogen has been made conductive at around 300 Gpa.
2) Discovery of MgB2 which clarifies that high Tc superconductivity is promoted by covalent
bonds which assure strong electron–phonon coupling.
These conditions can be fulfilled for covalent compounds dominated by hydrogen
N.W. Ashcroft (Hydrogen Dominant Metallic Alloys: High Temperature Superconductors? Phys. Rev. Lett.
92, 187002 (2004).
Ashcroft’s idea was supported in numerous calculations predicting high values of Tc for many
hydrides. So far only Tc ~17 K has been observed experimentally in silane under pressure.
The discovery of superconductivity 190 K in H2S has been posted on arXiv.org in December
2014 by the Eremet’s group.
.
37
A.P. Drozdov, M.I. Eremets I. A. Troyan, V. Ksenofontov, S. I. Shylin
Nature published 17 August 2015, doi: 10.138/Nature 14964
H2S: relatively easy to handle and predicted to transform to a metal and a superconductor
at a low pressure P<100 GPa with a high Tc<80 K
Li et al, J. Chem. Phys. 140, 174712 (2014).
Further investigations has indicated that at experimentally relevant pressures H2S is
unstable, decomposing into H3S and S.
PRB 91, 060511(R) (2015)].
H2S
S
38
H2S
D 2S
D 2S
H2S
𝑇𝑇𝑐𝑐 ∝ 𝑀𝑀−𝛼𝛼

𝛼𝛼~0.3
39
195 GPa
155 GPa
Type II
superconductor
Bc2 (0) ~ 70 T
Bc1 (0) ~ 30 mT
40
H3S
IBS-122
YBCO
MgB2
Tc [K]
200
38
93
39
Bc2 (0) [T]
70
60
>50
20-30
ξ [nm]
2.5
3
2.2
10
Bc1 (0) [mT]
λab (nm)
Ginzburg number Gi
pairing
30
125
10-3
BCS
40
20
100
200
180
50-100
2·10-5
>10-3
<10-5
BCS
Not BCS Not BCS
41
Another step towards achieving superconductivity at room
temperature has been done.
The myth that BCS superconductors can not be a high
temperature superconductor has been debunked.
There are many hydrogen-containing materials with strong
covalent bonding (such as organics) but typically they are
insulators.
In principle, they could be tuned to a metallic state by doping
or gating. High power available ab-initio calculation method
could facilitate exploration for the desired High Tc materials.
42
E. Bellingeri, C. Ferdeghini, A. Malagoli, CNR-SPIN (I)
D.Larbalestier, C. Tarantini, E. Hellstrom, NHMFL, Tallahassee, FA (US)
G. Grasso, D. Nardelli, M. Tropeano, Columbus, Genova (I)
R. Flukiger, CERN and University of Geneve (S)
M. Eisterer, University of Wien (A)
H. Kumakura, NIMS, Tsukuba (J)
Y. Ma, CAS, Beijing University (C)
K. Iida, University of Nagoja (J)
F. Kurth, IFW, (G)
J-I Shimojama, Aoyama Gakuin University (J)
G. Giunchi, Edison (It)
A. Yamamoto, Tokyo University of Agricolture and Technology (J)
X.X.Xi Philadelphia University, (US)
A. Gurevich, Old Dominion University (US)
43
44

Annotated Presentation, PDF

Transcription

Similar documents

IEEE SB Chapter Electron Devices Universidad de San

Map Inside 2002.qxd (Page 1)

Getting Started with Your Search

Internet Communication Beyond the Barrier of Death

IEEE Northern Canada Section Newsletter

Poster - Centre for Intelligent Machines

PDF Version - IEEE Control Systems Society

Carl R. Darnall Army Medical Center (CRDAMC) COL Mark

The Jacquard loom using punched cards to weave