DSI Journal 2006

Transcription

DSI Journal 2006

DATA
STORAGE
INSTITUTE
DATA STORAGE INSTITUTE
DSI BUILDING
5 ENGINEERING DRIVE 1 (OFF KENT RIDGE CRESCENT, NUS)
SINGAPORE 117608
TEL: (65) 6874 6600
FAX: (65) 6776 6527
A N N UA L
06/07
DATA STORAGE INSTITUTE ANNUAL REPORT 06/07
w w w. d s i . a - st a r. e du.sg
R E P O RT
location map
VISION
To be a vital node in global
community of knowledge
generation and innovation,
nurturing research talents and
capabilities for world class R&D in
next generation technologies.
MISSION
To establish Singapore as an
R&D centre of excellence in data
storage technologies.
Data Storage
Institute (DSI)
is conveniently
located within
the campus of the
National University
of Singapore (NUS)
at Engineering
Drive 1. It is
situated in the
vicinity of the Yusof
Ishak Hall, Raffles
Hall and Faculty of
Engineering
Wing 2.
DSI ANNUAL REPORT 06/07
0
02
director’s
report
04
scientific
advisory board
05
calendar
of events &
Highlights
FY2006/2007
13
75
99
industry
relations
research
community
technical
milestones
publications
corporate
members
students
research and
development
technical
profiles
intellectual
capital
patents
101
visiting professors
faculty collaborators
key research projects
136
organisation
chart
location map
0
DIRECTOR’S REPORT
DIRECTOR’S REPORT
FY 2006 has been another fruitful year for DSI as we strengthened our
interactions with the industry. We signed two significant licensing
agreements. One was signed with Symmatrix Pte Ltd to launch a new
product based on DSI’s Internet SCSI (iSCSI) Target Software Module.
DSI’s “All-In-One” (AIO) spindle motor tester was the other licensed to
Shenton Enterprise Company to manufacture and market in Singapore
and regionally. These collaborations reflect our commitment in helping
promising local companies to grow and globalize.
Aside from these collaborations, we initiated 19 R&D projects during the
past year. I am also pleased to report that a total of 437 service related
projects were carried out with the industry. Our Integrative Science
and Engineering Division contributed significantly, serving the industry
through our various R&D resources. Researchers at DSI were also given the
opportunity to lend their expertise to local enterprises through A*STAR’s
T-Up Scheme. We successfully seconded 5 staff to local enterprises
under this scheme. To engage the industry further, a total of 39 talks and
workshops were organized for local engineers. As at end of FY06, we have
33 members on the DSI’s Corporate Membership Scheme.
On the intellectual capital front, the growth continues as we evaluate
and align our R&D focus with the industrial trends and technological
advancement. I am pleased to report that DSI has filed 32 patents and was
granted 13 patents in the past year. A total of 264 papers were published at
key international conferences and prestigious journals. The past year also
laid the foundation for research collaborations with local universities and
other research institutes.
FY 2006 has seen several key technical achievements in both magnetic and
optical storage technologies. Our researchers have found that by using a
new intermediate layer, FePt films with coercivity higher than 12 kOe were
achieved at low temperature of 350 ºC. In the research of perpendicular
recording technologies, we have proposed hybrid soft magnetic
underlayers for perpendicular recording media to resolve the problem of
intermediate layer thickness, thereby improving the writability and also
reduce the T50.
In the area of servo control technology for supporting disk drives in mobile
applications, an advanced adaptive controller which is able to compensate
the shifting problem of resonance mode has been developed. Together
with the intelligent algorithm with neural network to compensate those
uncertain nonlinearilities in HDD, it forms a smart HDD servo system that is
more rigid to achieve a more robust and more accurate tracking.
In the field of high precision measurement for HDD, our spindle motor
team has successfully developed an accurate sensorless technology to
DIRECTOR’S REPORT
0
“Our research achievements would not
have been possible without human capital;
our staff and students. The DSI continues to
place emphasis on the expertise profile of our
research talents.
”
detect the rotor position of the spindle motor.
This sensorless detecting technology when
put together with a laser displacement sensor
is capable of measuring the BFH at a 10 nm
resolution and a 30 nm accuracy.
Seven PhD students and three Masters students
graduated last year. I am pleased to report
that five of these joined the local industry and
research organizations as researchers and
engineers.
Our continuous efforts to explore intelligent
storage solutions for OSD systems resulted in the
development of a new metadata management
strategy. This strategy can partition the metadata
based on the weight of each MDS, using a variant
B+-tree data structure and universal hashing
functions.
Our university linkages remain healthy. We
have altogether 13 staff holding either joint or
adjunct positions with the National University
of Singapore and the Nanyang Technological
University. Our good linkages are also reflected
in having four faculty members and associates
working with our staff on joint projects and
initiatives.
DSI has also step onto the research bandwagon
for consumer electronics. We are focusing our
work on home digital devices interoperability
and DLNA protocol implementation for AV
browsing and streaming. A home media server
that converges functions such as automated
discovery of Wireless HDD, streaming of audio/
HD-Video from wirelessly to HD-TV through the
server, and even allowing PDA to Browse AVContent of wireless HDD using DLNA protocol is
in development stage.
Our research achievements would not have been
possible without human capital; our staff and
students. The DSI continues to place emphasis
on the expertise profile of our research talents.
81% of our technical staff members have at least
a Masters degree, out of which 64% of these are
Ph.D holders. DSI is pleased to note that many
staff members remain in the industry when they
leave. As at end FY06, we have at least 21 staff
members who have left the Institute to take up
technical and research positions in the private
sector.
Students are an invaluable part of the DSI
research community. We have 40 graduate
students in our midst, and hosted some 293
undergraduate, JC and polytechnic students.
The latter group is attached to DSI through
programmes such as final year projects,
industrial attachments and internships.
Last but certainly not the least, I am pleased
to report that DSI clinched the 2006 National
Technology Award for the third year running.
The 2006 Award was recognition of our work in
advanced micro motor technologies used in hard
disk drive and miniaturized mechatronic systems.
We were also awarded the 2006 IES Prestigious
Engineering Achievement Award for our
innovation in providing precision measurement
of the nanometer spacing between head
and media. Both achievements showcased
technologies that are crucial for the HDD
industry as the recording density approaches
one Terabytes-per-square-inch (1 Tb/in2).
DSI continues to be a credible global player in
the field of data storage technologies. It is our
on-going mission to develop capabilities and
talents through a spectrum of research activities,
staying relevant and effective in transferring
technology and manpower to the industry.
DSI is ready for the challenges in the coming year
and will continue to push the limits of storage
technology research.
Professor Chong Tow Chong
Executive Director
0
SCIENTIFIC ADVISORY BOARD
SCIENTIFIC ADVISORY BOARD
Appointed by the
Agency for Science,
Technology and
Research (A*STAR),
the Scientific Advisory
Board (SAB) members
review, help develop
DSI’s technology
roadmaps, and identify
relevant research
programmes and
activities, to achieve
DSI’s research goals.
The SAB also assesses
the impact of DSI’s
scientific activities
in both local and
international R&D
scenes. Each SAB
member undertakes a
two-year tenure.
Chairperson
Dr Mark H Kryder
Member
Dr Alexopoulos Pantelis
Term of office:
1 February 2002 – present
Chairmanship:
1 February 2004 - present
Term of office:
Professor, Dept of ECE
Carnegie Mellon University, USA
Member
Dr John Best
Chief Technologist,
Hitachi Global Storage
Technologies Inc, USA
Term of office:
Member
Prof Tetsuya Osaka
Professor, Faculty of Science
and Engineering, Waseda
University, Japan
Term of office:
Member
Mr Paolo Cappelletti
Group Vice President,
Non-Volatile Memory
Technology Development,
STMicroelectronics, Italy
Term of office:
Vice President and General
Manager (Head Business),
Hitachi Global Storage
Technologies
Member
Mr Hubert Yoshida
Vice President,
Chief Technologist Officer,
Hitachi Data Systems
Corporation, USA
Term of office:
Member
Dr Shigeo R Kubota
Professor,
Tokyo University
Term of office:
0
CALENDAR OF EVENTS &
HIGHLIGHTS
calendar of events & highlights
0
calendar of
events & highlights
FY2006 was a fruitful year for DSI.
Our researchers clinched the National
Technology Award 2006 and the IES
Prestigious Engineering Achievement
Award 2006. Our other highlights of
the year were successful licensing of
Internet SCSI (iSCSI) Target Software
Module and the “All-In-One” (AIO)
spindle motor tester for market
development. We were also pleased
to have hosted Asia-Pacific Magnetic
Recording Conference 2006 and
Laser Doppler Vibrometers (LDV)
Conference, two regional conferences
successfully.
2006
April
n DSI played host to Mr Frank Levinson, Founder & Chairman,
Finisar Corp, USA
n DSI organized two seminars where invited speakers Prof
Yosi Shacham, Department of Physical Electronics, Tel-Aviv
University, Israel, and Dr Emad Girgis, National Research
Centre (NRC), Cairo, Egypt spoke on “Recent Advances in
NAND Flash Memory” and “Half Metallic Compounds for
Spintronics Devices” respectively.
May
n DSI and IDEMA kicked off the 1st DSI-IDEMA Corporate
Member Evening for FY06 with Mr Jim Chirico, Executive
Vice President, Global Disc Stoarge Operations, Seagate
Technologies, presenting an update on hard disk drive (HDD)
developments.
n DSI played host to ten distinguished visitors. They
were:
- Dr Hitofumi Taniguchi, GM of Tsukuba Research
Laboratory, Tokuyama Corporation, Japan.
- Mr Richie Tjong, MD of Symmatrix Pte Ltd,
Singapore.
- Ms Christine Chan, Director, Marketing A/P
McData, USA.
- Dr Gianguido Rizzotto, VP of STMicroelectronics,
Italy.
- Dr Noureddine Bouadma, Project Manager and
Dr Manuel Moreira, Technical Manager from
Telecom, France.
- Mr Kensuke Oka, Deputy Managing Director,
Hitachi Asia Ltd, Singapore .
- Mr Alex Shumay, Director of Business
Development and Strategy and Mr Felipe
Rodriguez, Program Director of Business
Development and Strategy from Hitachi Global
Storage Technologies, Singapore.
- Mr Hirata, Senior VP of Personnel & R&D, Seiko
Instruments Inc, Japan.
June
n DSI hosted the Telescience Storage Security
seminar where invited speakers include Dr Singa
Suparman, DSI, Mr Bill Lozoff, NeoScale Systems
Inc, USA, and Mr Jeff Nguyen, Finisar Corporation,
USA. Dr Lai Yicheng, Research Fellow in Aston
University, UK, was invited to speak on “Fibre
devices based on femtosecond laser inscription
technique for communication, biomedical and
sensing applications” in another seminar.
n DSI licensed its Internet SCSI (iSCSI) Target
Software Module to Symmatrix Pte Ltd to launch
a new product using this technology.
n DSI’s Office of Graduate Student Affairs organized
a Nanoscience Workshop at Victoria Junior
Colleage where researchers shared on the basics
of nanotechnology to 26 teachers from 11 JCs
and MOE.
n DSI played host to eight distinguished visitors.
They were:
- Mr Kuroda, Marubeni, Singapore.
- Mr Robert P. Oates, SVP & GM, Process Equipment
Group Veeco Instruments Inc, USA.
- Dr Jun Naruse, Corporate Chief Scientist, Hitachi
Ltd, Japan.
- Mr Mitsuhisa Sekino, Storage Product Group SVP,
Fujitsu Ltd, Japan.
- Mr Phil Maher, Board of Directors & Mr Koji
Kuroda, General manager, Marubeni & Thot
Technologies, Singapore & USA.
- Mr Katsuyuki Masuno, Associate Director,
Tokuyama Corporation, Japan.
- Dr Martin Winter, Project Manager, Clariant
Huningue, France.
0
0
July
- Dr Yoshito Tsunoda, President, CEO and Director
of Hitachi Maxell Ltd, Japan.
n DSI organized a seminar on “Magnetic Read Head
- Mr Kaiser Syed Karim, Executive Director,
Firmware Development Engineering, Seagate,
Singapore.
Perspectives & Challenges” and four workshops
on “Physics and Theoretical studies of magnetic
and spin-based devices”, “Application of Modern
Analytical Techniques on Failure Analysis”, “Fibre
Channel Essentials” and “Introduction to Network
Storage”.
an “Authentic Conversation” where Research
Scientist Dr S.N. Piramanayagam gave a talk on
magnetic media and storage media history and
trends to 40 secondary four students from Raffles
Institution.
n DSI played host to eleven distinguished visitors.
They were:
- Mr Martin Lynch, Executive Vice President, Mr
John Schaecher, Director of NPI, and Mr Andrew
Burdick, Manufacturing Operation” from Cornice,
USA.
- Mr Heng Vincent, Business Development
Manager and Mr Leow HS, Mechanical Design
Manager, ATS Automation, Singapore.
- Dr Guo Lin, Vice President of Product Integration
Engineering, SAE Magnetics (H.K) Ltd, China.
- Dr Hisahiko Iwamoto, Senior Research Scientist
and Mr Tomonori Matsunaga, Tokuyama
Corporation, Japan.
- Mr Richard Zippel, VP of Technology, Sun
Microsystem, USA.
August
n DSI hosted the following seminars and
workshops:
- Seminar on “Nano-imprint lithography” by Dr
Rachid Sbiaa, Senior Research Engineer, DSI.
- Seminar on “Introduction to Nanophotonic
Devices” by Prof Ho Seng-Tiong, Professor,
Engineering & Computer Science and Director,
Nanophotonics & Quantum Electronics Research
Lab, Northwestern University.
- Seminar on “High Frequency Inductance
Measurements and Performance Projections
made for Cusp-field Single Pole Heads” by a series
of speakers from the Department of Electrical
and Computer Engineering, St. Cloud State
University, Minnesota, USA, and Akita Research
Institute of Advanced Technology, Japan.
- Seminar on “Spin Transport in Magnetic NanoStructures” by Hao Meng from the Center for
Micromagnetics and Information Technologies
(MINT) & Department of Electrical & Computer
Engineering, University of Minnesota.
- Mr Liu Cheng, VP of Technology, Finisar
Corporation, USA.
- Seminar on “A Powerful FDTD Electromagnetic
Simulator for Current-Injection & All-Optical
Nanophotonic Semiconductor Devices using a
Multi-Level Multi-Electron Quantum Medium
Model” by Prof Ho Seng-Tiong, Professor,
Engineering & Computer Science and Director,
Nanophotonics & Quantum Electronics Research
Lab, Northwestern University.
- Mr S Iswaran, Minister of State (T&I), Ministry
Trade of Industry, Singapore.
- Training/Workshop on IP Storage by Debbie Lisa
George, Research Officer, DSI.
- Mr Lim Boon Huat, MD, Rhode & Schwarz
Singapore/Germary.
n DSI hosted SNIA WW Delegates Event, a
• Dr Toshihiko Omote, Officer, Core Technology
Center, Nitto Denko Corporation, Japan. networking event with SNIA WW and local
vendors.
n DSI played host to twelve distinguished visitors.
They were:
- Mr Christopher Lee, Applications Engineer,
Corning Tropel Corporation, USA.
- Mr Lou Kordus, Vice President of Technology &
Operations, Cswitch Corp, USA.
- Dr Nobufuji Kaji, Deputy General Manager,
Nidec Corporation Motor Engineering Research
Laboratory, Japan.
- Mr Yoshinobu Hirata, Senior Vice President
Seiko Instruments Inc, Japan.
- Mr John Wilkes, HP Lab Fellow, Hewlatt-Packard
Laboratories, USA.
- Dr Harald Pielartzik, Head of University and Dr
Gerhard Langstein, Head of New Technologies
Bayer Material Science, Germany.
- Mr Randall Choo, CEO, iTransAct Technologies,
Singapore & Malaysia.
September
n DSI hosted four seminars on microscopic theory
of current-driven domain wall motion, percolated
perpendicular media for HDDs applications,
addressing servo challenges for HDDs in Mobile
Applications, Mechatronics and Recording
Channel and a workshop on applied storage
systems.
n DSI hosted second DSI-IDEMA Corporate Member
Evening.
n DSI participated in Xperiment’06, an annual
science exhibition event.
0
10
They were:
- Mr Vinson Chua, MD, Asaiki Technology Pte Ltd,
Singapore.
- Mr Ron Goh, President of South Asia, EMC, USA.
- Mr Stan Kassela, Senior Director Equipment
Engineering, Seagate (Woodlands), Singapore.
- Dr Gianguido Rizzotto, VP, STMicroelectronics,
Italy.
- Mr Leong Amos, Hartec, Singapore.
- Dr Shinji Honma, Chief Engineer of Hard Disk
Department, Hitachi High Technologies, Japan.
- Mr Werner Goettel, Product Manager Materials,
Business Unit Materials, Schott Lithotec, Germany.
- Mr Terutoshi Komatsu, Executing Operating
Officer, GM, Business Promotion Department,
Ferrotec Corporation, Japan.
October
n DSI’s breakthrough innovation that provides
precision measurement of the nanometer
spacing between head and media won the IES
Prestigious Engineering Achievement Award
2006. The winning team comprises Dr Yuan
Zhimin, Dr Leong Siang Huei and Mr Ng Kawei.
n DSI’s research in spindle motor technologies
enable motors to be small, fast, silent, high in
power density, and reliable in uncontrolled
environments. For their outstanding
contributions to advanced micro motor
technologies used in hard disk drive and
miniaturized mechatronic systems, Dr Bi Chao,
Dr Jiang Quan and Dr Lin song received the
National Technology Award 2006.
a “Meet The Scientist Talk” at Singapore Science
Centre. Research Scientist Dr S.N. Piramanayagam
gave a talk on “Data Storage using NanoMagnets” to secondary school students.
n A Scientific Advisory Board (SAB) meeting was
organized to assess DSI’s scientific activities and
to review the technology roadmap.
n DSI hosted three seminars on turbulent model
and measurement techniques of airflow of
HDD, Spintronics, Nanomagnetism & Advanced
Magnetic Storage and mechatronics and
recording channel.
They were:
- Mr David Mosley, VP of Product Development,
Seagate, Singapore.
- Mr Chris Malakapalli, Senior Director of Emerging
Markets, Seagate, Singapore.
- Mr Hitoshi Matsushima, SVP of Storage Systems
Unit, Fujitsu Limited, Japan.
- Mr Covurn Loh, CEO, Hartec Asia, Singapore.
- Mr Joe Bunya, VP for Thailand operation, Mr Don
Blake, VP for Malaysia operation and Mr Dave
Rauch, VP for Magnetic Head operation , Western
Digital, US.
- Dr Geoff Archenhold, Director of Business
Development, Aston Science Park, UK.
November
n DSI hosted APMRC 2006 that attracted more
than 140 participants from over seven countries.
There were 33 invited speakers and 76 digests for
poster presentation on topics such as head-disk
interface, perpendicular recording media, servo
track writer and HDD spindle motors.
n DSI organized two seminars on beyond the limits
of magnetic recording and head-disk Interface
technology for ultra-high density magnetic
recording. There was also a workshop on
Enterprise Storage Management.
n DSI played host to four distinguished visitors.
They were:
- Dr Vei-Han Chan, Director of Technology, Cswitch
Corporation, US.
- Mr Mock Pak Lum, MD, Mediacorp Technologies,
Singapore.
- Mr Trevor Schick, VP of Global Supply Chain
Management, EMC, US.
- Dr Nicko Van Someren, CTO, nCipher, US.
December
n DSI hosted the LDV Conference together with
Thot Technologeis and Marubeni.
n DSI organized three seminars on magnetic
nanoparticles, holography data storage, 3D
Display and Other Optoelectronic Applications
and state, trend and future of non volatile solid
state memory. There were also two workshops on
plasmonics and applications in nanotechnologies
and the MCDATA-HDS SAN Workshop.
They were:
- Mr Guo Lin, VP, SAE Magnetics (H.K) Ltd, HK.
- Dr Junzo Kawakami, Vice President and Executive
Officer, Hitachi Ltd, Research & Development
Group, Japan.
- Mr Yoshifumi Mizoshita, Chief Technologist,
Fujitsu Limited, Japan.
- Dr El Mostafa Zindine, Director, FCI, Corporate
Research Center, France.
- Mr Farzin Forooz, Director, Sarir International (S)
Pte Ltd, Singapore.
- Mr Haruo Takeda, GM, Hitachi R&D Strategy, R&D
Group, Japan.
- Mr Teo Y Hin, President (CEO), Fulita International
Enterprises Pte Ltd, Singapore.
- Mr Joel Schwartz, SVP, EMC Corporation, USA.
11
12
2007
January
n DSI’s “All-In-One” (AIO) spindle motor tester which
was licensed to Shenton Enterprise Company
to manufacture and market the equipment in
Singapore and regionally.
n DSI organized a seminar on coding, signal
processing and waveform generation towards
1Tb/in² channels.
n DSI played host to two distinguished visitors.
They were:
- Mr Kuk Hyun Sunwoo, Samsung Advanced
Institute of Technology, Korea.
March
n DSI hosted the networking session at DISKCON
Asia-Pacific 2007. The AIO spindle motor tester
which was licensed to Shenton Enterprise
Company was also showcased at DISKCON 2007.
n DSI hosted four seminars on reshaping
technologies for tomorrow’s minature motors,
laser precision engineering from microfabrication
to nanoprocessing, near field optical recording
and heat assisted magnetic recording.
They were:
February
- Mr Sun Yu, Director of Integration Engineering
and Mr Takashi Honda, Senior Manager,
Component Technology Development, SAE
Magnetics (H.K) Ltd, Hong Kong.
n DSI played host to five distinguished visitors. They
- Dr Jimmy Zhu, Dr Fred Higgs and Dr Michael
McHenry, CMU, USA.
- Mr Tomiyasu Hiroshi, Fujielectric, Japan.
were:
- Mr Gerry Ong Teck Seng, Managing Director, VGS
Technology Pte Ltd, Singapore.
- Mr Takahiro (Tom) Asano, Sumitomo Corp,
Singapore.
- Mr Nobuyuki Takahashi and Mr Tomiyasu Hiroshi,
Fuji Electric, Singapore.
- Dr Beng Ong, Xerox Research Centre /
Programme Director of Polymer Electronics, IMRE,
Canada / Singapore.
- Dr John Chapman, University of Glasgow,
Glasgow, UK.
- Prof Vladislav Khomich, Russian foundation of
Basic Research, Russia.
- Mr Lim Chuan Poh, A*STAR Chairman.
DIRECTORS REPORT
RESEARCH &
DEVELOPMENT
technical milestones
technical profiles
013
14
research & development
The DSI continued
to make significant
advancements in both
magnetic, optical storage
and network storage
technologies. The key
research projects and
milestones achieved are
featured in this section.
Technical Milestones
Interactive Science and Engineering:
nEstablished capability for making uniform lubricant films for magnetic
hard disks and MEMs devices.
Mechatronics & Recording Channel Division:
n Software read channel - a comprehensive platform for evaluation of
channel algorithms provided by international researchers and for the
demonstration of 1Tb/in2.
n Low profile, high power density spindle motor design - miniature
yet powerful spindle motors for next generation HDDs and other
consumer products.
n High precision vision measurement system - for non-contact,
nanometer level precision measurement of spindle motor RRO/NRRO,
spindle motor fly height and spinning machine tools vibration
n 460kTPI on spin stand - nonlinear servo algorithms to demonstrate
ultra-high tracking accuracy.
n Accelerated shock and heat transfer analysis - Mathematically
rigorous model order reduction techniques that speed up HDD shock
resistance and heat transfer analyses significantly compared with
conventional finite element methods.
n Advanced turbulence models for airflow simulation - for predicting
the complex flow field of high spindle speed HDDs.
n Particle trajectory modelling and analysis - for predicting the
trajectories of contaminants in HDDs so as to propose strategic
locations for air filters in the HDDs.
Network Storage Technology Division:
nStorage security program and intrusion detection system build up.
nTechnology of OSD based storage system architecture for large scale
storage applications.
nLicensing of storage data transport protocol iSCSI to industry partner.
nLicensing of OSNPrep training course to
SNIA and 500 industry engineers have been
Spintronics, Media & Interface
Division:
trained to date.
nNew version of ABS design and air bearing
simulation program (ABSolution 2.0) was
Optical Materials & Systems
Division:
nProposed a theory of anomalous light
scattering in nanostructures with localized
completed. The new version is based on
Finite Element method with high efficiency
algorithm. It provides static and dynamic
analysis functions of air bearing sliders,
and is able to work with Ansys for more
plasmons.
comprehensive simulations. It also provides
nDeveloped new laser thermal lithography
many functions to solve the specific
technology.
nIntegrated the whole set of MDML optical
data storage platform and fulfilled the
writing and reading functions for both
problems in nanometer-spaced head-disk
interface. In addition, ABSolution features a
user-friendly Graphic User Interface (GUI) to
provide powerful pre- and post-processors.
reflective multi-level recording and
nUsing a new intermediate layer, FePt films
polarization multi-level recording.
with coercivity higher than 12 kOe were
nDeveloped a dynamical method to measure
achieved at low temperature of 350 ºC.
magnetic coercivity and remanence of hard
nBy control of the interface and element
disk with magneto-optical Kerr effect, and
doping, FePtX film with columnar grain and
built an experimental setup to demonstrate
grain size around 8 nm were achieved.
the feasibility of the method.
nDeveloped a laser nano-imprinting for large
nA new method to reduce the grain size by
inserting a “synthetic nucleation layer” was
area, fast speed, non-contact and maskless
proposed and patented. Grain sizes below 6
nanostructures fabrication.
nm pitch, with a distribution narrower than
nSynthesized phase change magnet materials
that demonstrate different optical, electrical
13% could be obtained using this method.
nA guided SAF MRAM has been developed
and magnetic properties at amorphous
that has advantages of no writing
and crystalline states by introducing spin
interference and directly writing. The GSAF
into phase change materials and realized
MRAM significantly increased the writing
reversible phase change.
nFabricated nano PCRAM cell down to 45nm
reliability and writing speed.
nFast media mechanical and magnetic
and found the correlation between phase
defects mapping technology was
transition speed and cell size.
developed.
15
technical profiles
16
Technical Profiles
Interactive Science and Engineering
The Integrative Science and Engineering
(ISE) division is involved in DSI projects and
solutions which are of an integrative science
and engineering nature. The division houses
projects that cut across various divisions and
is equipped with many high spatial resolution,
high surface chemical sensitive analytical
tools that have myriad of capabilities, such
as material outgas analysis, environmental
measurement, particle induced disk-drive
damage characterization methodology
and lubricant thin film deposition and
development. The ISE division works very
closely with industry partners on root cause
findings of contamination and defect on
media and slider, surface and interface
cleanliness examination, process monitoring
and investigation, and aims to provide
a one-stop advanced failure technology
support resource to the data storage
industry and related partners. The division
has since developed highly sensitive and
accurate methods for ultra-trace amounts of
chemical contaminants and low nano-particle
density determination. It has also developed
advanced lubricant thin film deposition
techniques and is currently exploring novel
lubricants for future applications including
Heat Assisted Magnetic Recording (HAMR) .
characterization, HDD reliability testing and
hard disk related environmental simulation
and analysis. We have experience in providing
a one-stop value-added technical support
and consultancy for failure analysis and
reliabilities/contamination analysis to our
industrial partners and R & D groups in DSI.
To gain a leading edge in the failure analysis
market, we are standardizing our analytical
services against ISO standard. Our industry
partners will benefit from it through a more
established failure analysis service.
Our lubricant research group has established
capability for making nanothin uniform
lubricant films for magnetic hard disks
and MEMs devices. The recently disclosed
nanothin lubricant film deposition technology
has attracted HDD and MEMs industrial
companies for patented applications. This
technology has the advantages in film
uniformity control particularly removal of
lube-lines and other deposition defects. In
addition, newly developed lubricant film
shows excellent performances in reducing
friction, anti-corrosion and significant high
thermal stability.
Areas of Focus
n Advanced failure analysis and technical
consultancy to data storage and related
industries.
n Ultra-sensitive high resolution surface
Milestones
Our Failure Analysis (FA) group has built
systematic project management policies,
enriched industrial failure analysis case study
database, internal R & D supporting case study
database, self-built library and technique
procedure database. The research in FA
group covers the development of analytical
metrology for failure analysis, ultra thin film
and interface chemical analysis, chemical
imaging and ultra-thin multi-layer
metrology for micro-contamination and
defect control.
n Advanced lubrication technology and
materials for current and future magnetic
recording hard disks.
n Tribology and tribochemistry study in hard
disk drive.
technical profiles
n Determination and control of ultra-trace
level accuracy, this division researches into
vibration reduction and containment through
in-depth studies and detailed analyses of
air flow, flow-structure interaction, wide
bandwidth mechanical system, MEMs
actuator and sensor, and low vibration
spindle motors and spindle driver design,
among other things. To further enhance
positioning accuracy, the division also works
on multi-sensing and multi-actuator active
control designs and intelligent sensor signal
processing algorithms.
contaminants in the environment.
n Reliability and chemical integration issues
in HDD such as micro-corrosion and
tribochemical failures.
n Filtration and control of particles in data
storage systems.
Capabilities
n Failure analysis and reliability testing.
n High spatial resolution surface chemical
analysis and imaging.
n Ultra-thin film characterization.
n Nanothin lubricant film technology.
n Tribological testing.
n Reliability test of magnetic recording media.
n Environmental and micro-corrosion testing.
n Solution protective materials and
technology for HDD related components
such as recording media, fasteners, etc.
n Contamination analysis and control
- dynamic headspace analysis for VOCs, cleanroom and disk drive air quality.
- ultra-fine particle dispersion and analysis.
n Nanoparticles testing.
In the area of signal processing, the division
looks at flex circuit and driver circuit designs to
achieve ultra-high speed signal transmission
with minimal electromagnetic interference.
Additionally, signal processing algorithms
are formulated to decipher recorded data
contaminated with noise from the recording
media and head. The division also works on
micromagnetic modeling to study the physics
of signal generation for ultra-high density,
next generation magnetic recording systems.
Areas of Focus
n Coding and signal processing.
n Electro-magnetic system design and
simulation.
Mechatronics & Recording Channel
Division
The Mechatronics and Recording Channel
(MRC) division focuses on enhancing linear
density and track density as well as the
robustness of recording systems through
control and signal processing algorithms,
novel digital and analog electronics, active
and passive vibration and heat transfer
management, and shock resistance
improvement.
With the objective of positioning the reader
and writer in recording systems at nanometer-
n Mechanics, heat transfer and fluid
mechanics.
n Advanced motor technologies.
n Advanced servo.
n Servo writing for recording systems.
Capabilities
n Recording channel modeling and analysis.
n Channel algorithm formulation [including
partial response, error correction code (ECC)
and reduced complexity iterative detection,
joint detection and timing recovery,
17
technical profiles
18
RS code, LPDC code], optimization and
implementation.
n Micromagnetic modeling.
n Electro-magnetic system design (including
spindle motor, voice coil motor and frontend signal transmission), analysis and
optimization.
n Servo algorithm formulation.
n Servo track writing.
n Mechanical design, simulation and analysis
of recording systems.
n System level, interdisciplinary simulation
and analysis.
Network Storage Technology Division
The Network Storage Technology (NST)
division is on the top of information
technology and storage industry value chain.
The division was established in July 2000
and it is focusing on the research of storage
system architecture, storage security and data
protection, system simulation, and consumer
storage application. It aspires to create
and develop innovative technologies and
solutions for network storage players. This in
turn facilitates the creation and development
of local industry through the transfer of
technology expertise and capabilities.
In 2002, the NST division also established
the first vendor-neutral Network Storage
Laboratory (NSL) in Asia which serves as a
premier centre to promote research and
deployment of inter-operable storage
networking technologies. The heterogeneous
laboratory also offers comprehensive training
and certification programs to develop skilled
manpower in network storage.
The consumer electronics storage group
was also formed in May of 2006 to address
the ever growing demand of storage for
home users. With this effort, NST division
aims to quickly build up the capability on CE
related technology and embedded system
development.
Areas of Focus
n Storage security.
n Intelligent object-based storage systems.
n Network storage modeling and simulation.
n On demand storage provisioning.
n Consumer electronics storage research.
n Network storage system benchmarking,
development and deployment for high
performance applications.
Capabilities
n Storage algorithms research and
development.
n Object-based storage technology.
n Storage transport protocols analysis and
design.
n Simulation of storage systems and storage
networks.
n Embedded system development for storage
applications.
n Digital home networking research and
development.
n File system, kernel and device drivers design
and implementation.
n Storage system and technology
performance analysis, testing,
benchmarking and evaluation of network
storage systems.
n Network storage technology training and
certifications.
Optical Materials & Systems Division
The Optical Materials and Systems (OMS)
division is on the leading edge of developing
the fundamental research of the science and
innovative solutions in the areas of optical
storage technology, solid state memory and
optical engineering.
technical profiles
In the pursuit for storage technologies with
high density, high data transfer rate, low
cost, and high reliability, the division has
cultivated expertise in optical recording
media , optical data storage system, nonvolatile phase change random access memory
(PCRAM), laser micro/nano-processing and
optical imaging. Research activities have
been emphasized on the development of
advanced Blu-ray discs, 4th generation optical
recording, nano-scale PCRAM with new phase
change materials and also its application in
reconfigurable devices.
Development of non-volatile, non-rotation,
high density, fast, and super performance
phase change random access memory
(PCRAM) and application on reconfigurable
devices.
n Micro modeling, simulation and mechanism
study of PCRAM.
n Memory and switch cell design.
n Nano PCRAM cell and array fabrication.
n Ultra fast PCRAM tester development.
n Memory and switch cell characteristics.
Optical engineering
n Laser technology and macro/nano-
The OMS division will continue to develop
core competencies in optical storage, solid
state memory and optical engineering,
buildup intellectual properties portfolio,
enhance the industry cooperation, and
strengthen its manpower training capability.
More efforts will be put on to explore new
technologies and provide innovative solutions
for future generations of storage including
cognitive technologies.
processing for data storage applications.
n Ultra short pulsed laser.
n Optical bio imaging.
n Laser nano patterning.
n Tester instrumentation.
n Laser thinning.
Capabilities
n Modeling, simulation and software
development for optical system and media.
n Thin-film deposition and characterisation
Areas of Focus
Investigation on 4th generation optical
recording
n 4th generation optical storage solution.
n Development of test platform.
n Heat assisted magnetic recording (HAMR)
(optical pick-up).
n Ultra fast optical reaction testing system for
optical and magnetic media.
n Volumetric optical recording technology
and materials.
n Nano ultra fast phase change.
n Ultra fast phase change.
n Laser thermallithography.
n Two-color nonvolatile and high-speed
recording technology.
n Surface plasmon optics.
technology.
n Optical media design.
n Manufacturing technology for CD-RW, DVD
recordable, DVD re-writable and Blu-ray
disks.
n Optical pick-up unit design and
development.
n Testing technology and platform
development for optical pick-up and optical
media.
n Device design, modeling and software
development for PCRAM.
n Fabrication technologies for PCRAM and
switch.
n Characterisation technology and tester
development for PCRAM and switch.
n Laser micro-nano processing and
characterisation technologies for data
storage media.
19
technical profiles
20
n Nano patterning and fabrication.
n Optical system design and fabrication.
n New material syntheses.
Spintronics, Media & Interface Division
The Spintronics, Media and Interface (SMI)
division focuses its activities in relentless
development and exploration of enabling
technologies for future extremely high
density magnetic recording and novel solid
state memory devices and technologies.
Its main research activities in 2006
include nano-magnetics and advanced
recording media, spintronics and sensor
technology, nanotribology and low flying
height technology, nanometrology and
instrumentation, recording physics, and
exploration of new information storage
mechanisms and systems.
FY2006 has been a rewarding year for the
researchers in SMI division. The recording
system and instrumentation team won the
Prestigious Engineering Achievement Award,
Institute of Engineers Singapore.
FY2006 was also a productive, fruitful and
pleasant year for SMI researchers in terms
of developing and transfer of technologies
to the data storage industry. Researchers
participated in the organization of various
international conferences, including, the
Joint MMM-Intermag conference, and the
Asia-Pacific Magnetic Recording Conference,
among others. In all, our researchers
generated more than 70 papers and delivered
7 invited talks in top level international
conferences. In addition, more than 90
students were trained in 2006.
processes, advanced testing and evaluation
technology, low flying height head-slider
technology, novel reading head sensor
technology, and new magnetic memory
concept and devices.
Areas of Focus
The following are the specific directions in the
various areas of focus:
Nanomagnetics and media technology
n CoCrPt-X media technology and processes
towards 500 Gb/sq-in areal density.
n Small grain size and narrow grain size
distribution.
n Novel intermediate layer technology for
perpendicular magnetic recording.
n Novel overcoat technology.
n Enabling media magnetics and structures
towards 1000 Gb/sq-in areal density and
beyond.
n FePt media, low temperature processes and
technology.
n Media post-processing technology.
n Nano-cluster sputtering technology and
processes.
Spintronics and devices
n Half metallic CPP for 2 Tb/sq-in and beyond
area density.
n Low RA MTJ using new barrier materials.
n Noise characterization of TMR heads for
future high density magnetic recording.
n Toggle reader and RA reduction scheme.
n Spin torque and spin transfer switching.
n Spintronic device based on spin Hall effects.
n Spin gauge field and Berry phase theory in
spintronics.
n CPP head, new structures and new materials
towards Tb/sq-in area density.
The researchers also worked fruitfully
with their industry partners in all the
division’s major areas of focus including
new perpendicular media technology and
n TMR head and technologies.
n MgO MTJ and low RA MTJ sensor
technology.
technical profiles
n Sensor fabrication process.
n Novel head structure design and new
n Micromagnetic modeling.
material development.
n Flux guide and side shielding reading head.
n Spintronic device design.
n Writing head design and modeling
n Green function modeling of spin transport.
for advanced perpendicular magnetic
recording.
n MRAM technology and new structures.
n Design concept exploration and
demonstration of new magnetic memory
devices.
n Spintronic Physics.
n Magnetic semiconductors.
Head-disk systems
n Modeling & simulation tool development for
Nanomagnetics and magnetic media
n Media sputter deposition and post-process
capabilities.
n Characterization technologies for
perpendicular recording media (ranging
from macro-magnetics to nano-structures).
n Thin film technology, magnetron
development, vacuum technologies.
n Nano-cluster deposition for fine grains and
narrow grain size distribution.
head disk interface.
n Dynamics of air bearing-slider-suspension
system.
n Extremely low flying height technology.
n Exploration of novel optical flying height
testing technology.
n Slider fabrication process and optimization.
n Design tool development for slider-disk
interface.
n Actuated sliders and technology.
n Slider-lube interaction analysis and
characterization.
n Gliding and burnishing slider technology.
Recording systems and nanoinstrumentation
n Recording physics and micromagnetic
modeling.
n New assisted writing technology.
n Recording performance testing technology
and magnetic integration.
Nano-mechanics, nanotribology and headdisk interface
n Nano-aerodynamics, air-bearing technology
and low flying height slider design and
fabrication capability.
n Nano-actuator and advanced suspension
technology.
n Modeling technology for disk, air-bearing,
slider and suspension systems.
n Advanced testing technology for nanometer
spaced head-disk systems.
n Overcoat and lubrication process and
technology.
Recording physics and nanoinstrumentation
n Recording physics and micromagnetic
simulation tools.
n Recording performance characterization
and magnetic integration.
n Nano-metrology and instrumentation.
n Nano-metrology and instrumentation.
n In-situ and optical FH testing technology.
n Media mechanical and magnetic defects
Capabilities
Spintronics, RW Head and MRAM
n Fabrication and characterization of CPP spin
valve and TMR read head.
mapping technology at tens nm lateral
resolution.
n High repeatability low FH testing
technology and flying dynamic
characterization.
21
22
integrative science
and engineering
1. Advanced Failure Analysis Methods
and Technique Development
Failure analysis and prevention are important
to all engineering disciplines, especially in the
production of high precision devices. To keep
pace with the ever-increasing requirements
on the metrology service, we are pushing
ourselves to reach the detection limits of the
current available analytical tools, to develop
and upgrade new testing capabilities, and to
explore new procedures to solve challenging
failure cases.
(a) Focus Ion Beam (FIB) and Auger Electron Spectroscopy (AES) technique
on buried contamination
Defects are often not detected immediately
after its occurrence but after subsequent
processing of the media. Usually, it is
detected during the certified test after sputter
deposition of the different layers. For defects
that are located on the surface, AES can be
utilized to analyze it. AES as a surface analysis
RIGHT
Figure 1. AES elemental
map on the cross
sectional surface of the
buried defect.
technique with an analysis depth of 5 to
50 Å can analyze the very surface of a sample.
For buried defects or defects that are buried
under layers of coating, it can be exposed by
ion milling or FIB cross sectioning. However,
the former would take a lot of time before
the buried defect is exposed. Furthermore,
sputtering artifacts can develop which may
hinder the characterization of the buried
defect. The characterization of a buried defect
by a combination of FIB with AES elemental
mapping is illustrated in Figure 1.
From the elemental map overlay, the nature
of the buried defect can be determined and
classified as a C contaminant. The combination
of FIB with AES is a powerful tool to quickly
expose a buried defect for analysis. Moreover,
FIB can be utilized to investigate the interior
of the buried defect. This technique proves
to be useful in both HDD and semiconductor
industries.
Figure 1.
(a) SEM image after FIB cross section
Ni1
C1
Pt4
(b) AES elemental map of Ni, C and Pt
(c) Elemental map overlay
(b) Non-destructive approach towards oxide thickness measurement
Where,
θ : detection angle with respect to the
sample surface
λm : Inelastic Mean Free Path (IMFP) of
photoelectrons propagating through the
metal
In the data storage related industry, the
determination of thin film thickness is a
frequently requested analysis. Very often, the
non-destructive method of determining the
thickness is preferred over the destructive test.
Reasons for the selection include preferential
sputter effects, shorter analysis time and
minimal damage to the sample surface
permitting the same sample to be used for
subsequent tests.
In this report, the relative thicknesses of tin
oxide layers on three solder balls, that have
undergone different annealing processes,
were determined using both the destructive
and non-destructive methods. The order
of relative thickness between the samples
analyzed with each method was also
compared.
In the destructive depth profile method, the
tin oxide thickness was estimated using the
full width half maximum (FWHM) of the O
profile. The result showed that the relative
thickness of the tin oxide layer, in decrease
order, was as follows:
Sample 3 > Sample 1 > Sample 2
In the non-destructive method, the relative
thickness of tin oxide film on the solder ball
was determined using following equation:
23
λo : IMFP of photoelectrons propagating
through the oxide
Cm : Volume densities of metal atoms in metal
Co : Volume densities of metal atomic in oxide
Io : Photoelectron intensity of the oxide film
Im : Photoelectron intensity of the metal substrate
The detection angle of 45º was constant
throughout the analysis. For all three samples,
Cm and λm were the same as they are all tin
solder balls and Co and λo were constant
assuming the type of oxide on the samples is
the same. This suggests that for comparison
purposes, a higher ln(Io/Im) will indicate a
thicker tin oxide layer is present. The Io and
Im value is the product of the total area of
the Sn3d5 narrow scan spectra and the %
area fraction of the oxide and metal peak,
respectively. Hence, Io/Im can be calculated
by taking the ratio of % area fraction of oxide
to metal peak in the Sn3d5 narrow spectra,
which are shown in Figure 2. The ln(Io/Im)
values are summarized in Table 1.
% Area Fraction
Solder Ball
Io
Im
ln(Io/Im)
Sample 1
84.78
15.22
5.570
Sample 2
73.95
26.05
2.839
Sample 3
91.62
8.38
10.933
LEFT
Table 1. ln(I0/Im) values
of the three samples.
24
integrative science and engineering
As detailed in Table 1, it was observed that
Sample 3 has the highest ln(Io/Im) value among
the three solder balls analyzed implying the
thickest tin oxide layer, while Sample 2 has the
lowest ln(Io/Im) value.
Although both methods use different
approaches to determine the relative film
thickness, the order deduced was identical.
Thus, the use of the non-destructive method,
which has the advantage of minimizing
surface damage, can be used to reliably assess
relative film thicknesses.
2. Ultra-Uniform Nanothin Lubricant Film
Technology
The uniformity of the lubricant thin film on
hard disk surface is important as it affects the
slider-disk flying stability and the hard disk
recording performance. In the worst case
RIGHT
Figure 2. Narrow scan
spectra on Sn3d5 peak
of tin solder ball (a)
Sample 1, (b) Sample 2,
and (c) Sample 3.
scenario, it can cause head/disk interface
failure. Ultra-uniform nanothin lubricant film
is necessary for ultra-stable flyability which is
required by high data storage technology.
During the lubricant dip-coating process,
lubricant lines can be generated due to
environmental vibration and surface wave
dissipation. Our invention allows precise and
accurate positioning and hence removal of
the lubricant lines at any position on the
disk. Figure 3 shows our dip-coating machine
and the uniformity of the lubricant thin
film. The advantages of our lubricant dipcoating process also include (1) convenient
removal/refill of lubricants & cleaning, (2) no
tubing contamination, (3) scale up for mass
production and (4) shorter operation time as
compare to draining lubrication process.
Figure 2.
Figure 3. (a) Our
dip-coating setup. (b)
Typical lubricant layer
after dip coating. (c)
Environmental vibration
caused lubricant lines.
(d) Middle line caused
by surface tension. (e)
Lubricant film deposited
by our technology.
(a)
(b)
Figure 3.
(a)
(b)
(c)
(d)
(e)
3. High Temperature Lubrication and Its
Application to HAMR
resistant abilities of the lubricant films
and the lubricant evaporation, desorption
or decomposition properties under laser
shinning.
Heat Assisted Magnetic Recording (HAMR)
is a very promising technology to achieve
Tbs/in2 areal density. In this technology,
the magnetic recording media needs to be
heated close to the media courier temperature
within a few nanoseconds by a beam of
laser. The heated spot is as small as the
written bit. During HAMR writing, not only
the magnetic layers are heated, the carbon
overcoat and lubricant layer are also affected.
Lubricant thermal stability therefore becomes
critical under extremely high temperature.
Currently commonly used lubricant has been
proven to be unsuitable for this application.
Therefore our research group is working
towards developing new lubricants for HAMR
applications.
By jointly working with our sister institute
IMRE, we have developed a new lubricant and
its nanothin lubricant films on the magnetic
hard disks. This new lubricant is stable under
328 ºC in N2 environment. The frictional
coefficient and the water contact angle of the
new lubricant thin film can achieve 0.06 and
830, respectively. The corrosion resistance
of the new lubricant thin film is better than
commercial lubricants such as Z-DOL and
A20H. The mobility of the new lubricant thin
film is between Z-DOL and A20H thin films.
Our other efforts in this project include the
development of an even higher thermal
stable lubricant thin film and a noval hard
disk multilayer design to avoid lubricant
layer damage under laser shinning. Figure 4
shows another recent developed lubricant
is thermally stable under 408 ºC in N2
environments and the magnetic recording
media with a heat sink layer enables the
lubricant to remain unchanged under laser
shinning condition.
To develop new lubricants for HAMR
applications, both the thermal stability and
the slider-disk tribological properties need to
be considered. Factors affecting the slider-disk
tribological properties include the bonding
properties between the lubricant thin film and
the carbon overcoat, the lubricant transfer
between the slider and the disk, the corrosion
Figure 4.
Percentage Mass
LEFT
Figure 4. (a) TGA results
showing the lubricant
stability at 404 ºC in N2
and (b) The effect of
heat sink layer under
laser shinning.
(a)
20min 9min 7min 5min 3min Z-dol film on
normal media
25
Z-dol film on media
with heat sink layer
(b)
Lube1 film on
Normal media
Lube1 film on media
with heat sink layer
26
mechatronics & recording
channel division
RIGHT
Figure 1. Runout
measurement based
on Laser Doppler
Vibrometer.
Measuring Spindle Motor Runout and
Bearing Floating Height
With Nanometer Resolution
(a) Runout measurement dased on
precise rotor position index
and laser doppler vibrometer
The spindle motor runout and bearing floating
height have a great effect on the achievable
track density of the hard disk drive (HDD).
To meet the high resolution measurement
requirement, the MRC researchers have
successfully developed two unique solutions
in 2006. These solutions have enriched DSI’s
non-contacting motor testing technology
and the functions of AIO spindle motor tester,
an invention of DSI which has been widely
adopted by the HDD industry worldwide.
DSI has developed an accurate sensorless
technology to detect the rotor position of
the spindle motor. The rotor signal, together
with the Laser Doppler Vibrometer, can be
used in the implementation of precision
measurement of spindle motor runout in
both axial and radial directions. The resolution
of the method developed is better than 1
nm and the accuracy can reach 0.2% of the
measured values. These are much better than
the conventional methods adopted by the
HDD industry.
Figure 1.
Figure 2. Axial runout
measurement.
Figure 2.
(b) Absolute laser displacement sensor based on precise rotor position index and bearing floating measurement
and quality control. The BFH varies while the
motor is in the starting phase, and it needs 2-3
minutes to enter the stable state. Therefore,
absolute displacement sensors must be used
to detect the BFH.
Nowadays all HDD spindle motors use fluid
dynamic bearings (FDB) to reduce the non
repeatable runout and acoustic noise. For
FDB, the rotor position of the motor in the
axial direction varies as the motor spins. The
bearing floating height (BFH) is in the range
of 20 µm while the spindle motor spins up
from rest to the rated spin speed. Knowing the
BFH accurately is important for HDD design
Figure 3.
27
MRC researchers have proposed using a laser
displacement sensor with their unique rotor
position sensorless detecting technology
to measure the BFH. The proposed method
can achieve a 10 nm resolution and a 30 nm
accuracy.
LEFT
Figure 3. Bearing
floating height
measurement based
on laser displacement
sensor.
Figure 4. Bearing
floating height
measurement.
Figure 4.
28
mechatronics & recording channel division
Servo Algorithms for High Density & High
Robustness Hard Disk Drives
Hard disk drives are expected to be used
in many different applications with very
stringent requirements. They are not only
expected to offer high storage density, but
high robustness as well. The demand for
high robustness is understandable as more
hard disk drives find their way into consumer
electronics which are subjected to harsh and
highly unpredictable environment.
(a) Advanced intelligent servo control for disk drives in mobile application
Next generation hard disk drives are to be
used in an environment that comes with high
external vibrations and wide temperature and
humidity range. The greatest challenge to
servo is that the servo needs more robustness
and more accurate tracking accuracy.
Traditionally, HDD servos are designed
using linear control theory. Current disk
drives utilize typical linear closed-loop
digital control systems, based on position
information that is encoded onto the disks
during the manufacturing process. PID type
controllers were used initially, and these
are subsequently augmented with notch
filters that suppress mechanical resonance
RIGHT
Figure 1. Smart servo
for HDD.
Figure 1.
modes, thus increasing the bandwidth. Loop
shaping methods are utilized for some of
these higher order servos. However, all these
methods suffer from the well-known Bode
Integral Theorem, which states that for a
Linear Time Invariant (LTI) control system with
an open loop transfer function of relative
degree 2 (which is the case for all physical
systems), the integral of the amplitude of the
sensitivity function in logarithm scale is zero.
As a consequence of this theory, if the servo
sensitivity transfer function is designed to
reject more vibrations in some frequencies, it
will amplify vibrations at other frequencies,
which is also known as the “water bed effect”.
With the use of intelligent control methods,
the control system is no longer LTI, but
nonlinear and time-varying. As a result, closed
loop performance based on the nonlinear
plant model under intelligent control is not
conclusively limited by the Bode Integral
Theorem as in the case for LTI systems.
In view of the challenges in the application
of HDD in mobile environments and the
limitations of LTI, we performed rigorous and
extensive investigations, including modeling
and prediction of tracking error induced by
excessive external vibrations and developed
fast intelligent disturbance observer for
const
Adaptive tuning
Nonlinear Inner Loop
^
f(x)
Feedforward Tracking Loop
xd
e
KT
r
Yd
Comp. const
disturbance
Outer Tracking Loop
NN1 - Model
Error comp
u
KV
Robust Control
Term
Jump fn NN2
Friction comp.
vc(t)
x
HDD System
compensation of the significant disturbances.
We developed an advanced adaptive
controller which is able to compensate the
shifting problem of resonance mode. We
are also developing intelligent algorithm
with neural network to compensate those
uncertain nonlinearilities in HDD. With
combination of these intelligent algorithms,
we are developing a smart HDD servo system,
as shown Figure 1. With application of the
intelligent algorithms in inner loops, the HDD
system will be more rigid and more allocated
and it can achieve a more robust and accurate
tracking.
Figure 1 shows us the universal HDD
experimental setup. At the begin, we will use
an enclosed HDA from commercial HDD and
design a read/write channel board and DSP
board and implement with DSI firmware.
The DSI servo firmware can communicate
with preamplifier and read back the servo
pattern, and pass though the appropriate
demodulation scheme where we can get out
the position error signal.
To enable us to use HDD as an equipment
such that to investigate the real issues for HDD
in application of mobile environment, we are
building a universal HDD experimental setup
very close to real hard disk drive, (Figure 2)
with a very flexi and reconfigurable read/write
servo channel, (Figure 3).
Figure 2.
Voice coil motor
(VCM)
(b) Soft intelligent sensors and its applications for magnetic data storage systems
The objectives of this study are: (1) to
propose an effective way to enhance
vibration rejection capability of a precision
motion control system; (2) to understand
and study optimal way to design nonlinear
observers for predicting vibrations; (3) design
intelligent disturbance sensors (observers)
without additional sensors; and (4) verify the
Pivot bearing
Spindle motor
Disk
Baseplate
Flexible printed circuit
Arm Suspension
(FPC)
(E-block)
Slider/Head
Figure 3.
PC
DSI Servo Firmware
R/W Channel with PES demodulator
VCM + Spindle driver
DSP Board
JTAG
29
LEFT
Figure 2. DSI Servo
Firmware
Figure 3. Universal read
write channel.
30
intelligent disturbance sensors in hard disk
drives servo systems and demonstrate the
effectiveness of the sensors and the vibration
rejection method.
The topic is innovative in that it looks outside
the existing linear feedback control design
methods, and attempts to establish a design
frame work for sensing the disturbance in
a precision motion control system using all
the information we have from the plant and
the process. The application of the design
methods to hard disk drive servo system is
expected to significantly improve the tracking
accuracy, and thus support the increase areal
density in magnetic recording systems.
RIGHT
Figure 4. Control
structure of a plan
P(z) with Youla
Parameterization
approach and
adaptive nonlinear
compensation.
A typical achievement can be seen as follows.
Figure 4 shows the utilized control structure,
which involves the linear controller C(z)
designed on the basis of KYP Lemma, and the
adaptive nonlinear compensator. The error
rejection function z/w is plotted in Figure 5,
which means the nonlinear control produces
a better rejection to disturbances of low
frequencies, and without any sacrifice to high
frequency disturbance rejection. The power
spectrum of PES NRRO is shown in Fig. 6. It
is observed that the error is much lowered
by 80% before 400 Hz, and no cost in higher
frequency range is paid. Overall the 3σ of true
PES NRRO is improved from 6.0 nm with uL to
5.5 nm with uL+uN.
Figure 4.
w
z
n
C(z)
y
uL
K(z)
uq
Q(z)
d
g
u
P(z)
uN= –g~
eq
Figure 5. Comparison of
error rejection functions.
Nonlinear
compensator
Figure 5.
Figure 6.
10
1
0
0.9
-10
0.8
NRRO magnitude(µm)
Magnitude(dB)
Figure 6. PES NRRO
power spectrum with
linear control designed
via KYP Lemma and
nonlinear disturbance
compensation.
-20
-30
-40
-50
-60
-70
-3
KYP
KYP with nonlinear estimation
0.7
0.6
0.5
0.4
400Hz
0.3
0.2
-80
-90 1
10
x10
KYP with nonlinear estimation
KYP
10
2
3
10
Frequency (Hz)
10
4
0.1
0
0
1000
2000
3000
4000
5000
Frequency (Hz)
6000
7000
8000
9000
Signal Generation and Processing
for Ultra-high Density Perpendicular
Recording
(a) On signal generation
poles. The results obtained from this write
field model, are compared with finite element
simulations. The model is expected to be
useful for building recording channel models.
Computer modeling using FEM is on-going,
computational results are obtained for various
designs of write heads and are compared with
analytical predictions.
The research in the area of physics based
modeling of signal generation processes in
ultra-high density perpendicular recording
(more specifically for a density level up to 1
Tb/in2) has attracted great attention in recent
years as at such high density the effects
due to three dimensional nature of the read
head field and the medium field become
more pronounced. As the recording density
increases the interference between the
recorded magnetization transitions and/or
the neighboring tracks and the write field
also demands more attentions. A strong
interest in using the patterned media for
ultra-high density recording also requires
a better theoretical understanding of the
signal generation processes considering
the interaction between the medium fields
generated by the recording medium islands
in both the down-track and the cross-track
directions. Our research effort focuses on the
following areas:
(i) Modeling of the signal recording
processes
Theoretical studies of the effects of
nonlinear transition shift in perpendicular
recording process are being carried out
using both analytical method, and numerical
simulations using finite element methods
(FEM). An analytical method which can be
used to analyze the problem quantitatively
is introduced. In analyses of the effect of
recorded transitions, the demagnetization
field due to written patterns on the recording
medium is taken into consideration in the
field solution for a writer head with shield
(ii) Micromagnetic model of recording medium response and analysis of medium fields
We have successfully built up capability in
physics based model and simulations of
magnetic recording media for the purpose
of studying signal generation processes. This
is essential for the theoretical understanding
of such processes and for the effort to push
the technologies in recording channels and
servo control towards a density level of 1
Tb/in2. The set of modeling procedures to
analyze the PRM process for signal generation
involves the micromagnetic simulation of
the medium transitions based on which the
micro-track parameters are extracted to build
the statistical model for signal generation.
The micromagnetic simulation can be carried
out using either commercial software tool
or a software based on micromagnetic FEM
that is accelerated with FFTM. The numerical
technique developed in-house is useful
for the application of the finite element
micromagnetic modeling in ultra-high density
magnetic recording.
(iii) Modeling of the signal reproducing processes
A 3D model has been developed to
obtain the solution of magnetic fields in
perpendicular read heads, which is in turn
useful for predicting the playback waveforms
31
32
in perpendicular magnetic systems. The 2D
solution can be used to study the effects
of non-symmetric read head structure and
the finite permeability of the soft-magnetic
underlayer. The results obtained from the
analytical solution are verified by numerical
simulations using finite element methods.
An extension of the method to solving the 3D
read head field problem is also discussed in
the paper. From the 3D solution the spectral
response function is given in the form of 2D
Fourier transform which can be useful for
analysis of the cross-track effects due to the
Figure 1.
1.2
d = 5nm, – s = 1000
d = 5nm, – s = 10
d = 25nm, – s = 1000
d = 25nm, – s = 100
1
0.8
ABS potential
RIGHT
Figure 1. Effects of SUL
permeability (results
computed for two
different values of the
ABS-to-medium gap,
d=5 nm and d=25 nm).
three-dimensional nature of the recorded
transitions on magnetic media. The model is
useful also for studying the signal reproducing
processes in PMR systems using patterned
media. Figure 1 shows the influence of the
permeability of the soft-underlayer (SUL)
on the read head potential distribution. In
Figure 2, the distribution of the flux density
component in the y-direction (perpendicular
to recording medium plane) is shown.
With the 3D solution of the read head field
available, we are able to calculate the spectral
response function in the form of 2D Fourier
transform, as shown in Figure 3.
Figure 2. Distribution of
flux density component
in y-directions.
Figure 3. Spectral
response function of
read head in a form of
2D Fourier transform.
0.6
0.4
0.2
0
-0.5
-0.25
0
0.25
Sensor thickness/shield - shield distance
Figure 2.
Figure 3.
0.5
(b) On signal processing
perpendicular magnetic recording. An
analytical two-dimensional single pole head
developed by DSI is used in the simulation.
The recording medium is modeled as threedimensional random Voronoi grains with 15%
diameter variation. This construction based on
pseudo Voronoi algorithm has been validated
as it is known to approximate well the media
topology created from sputtering. We further
introduced a small exchange coupling to the
media to balance the reduction in energy
caused by self-demagnetization of isolated
grains. To model the thin film media more
precisely, the perpendicular media anisotropy
axis is assumed with 3 degrees of deviation.
Most previous work on channel design for
future perpendicular recording systems
assumes a simple arc tangent model to
approximate magnetic transition, where
Taylor expansion is usually used to simulate a
channel corrupted with transition jitters.
These simplifications are acceptable only for
lower recording densities and smaller jitter
amount as compared to a single bit length.
With the recent recording density boosts, it
makes the simplified model less accurate as
approaching Tbit/in2 era.
In this report, we present a fast, geometricdependent approach to model random
readback pulses. The noises from zig-zag
boundary of magnetic transitions are
captured using the microtrack model. In
contrast to previous works that assumes
known microtrack parameters, we propose
a systematic approach to derive geometricdependent parameters, namely transition
probability density function (pdf ), cross-track
correlation and partial erasure (PE) threshold,
based on micromagnetic simulation results.
To demonstrate the feasibility of the proposed
model, we present BER performance of
high-rate low-density parity-check (LDPC)
codes transmitted over the channel detected
by a turbo equalizer based on the noisepredictive (NP) BCJR algorithm. The software
recording channel (SWRC), which is a modular
simulation platform developed at DSI that
enables researchers in various areas to
integrate their work and perform BER testing
using real channel data, is also introduced.
(i) Readback pulses modeling
We first used micromagnetic simulation to
model the read/write process for 1 Tb/in2
Next, we derived the microtrack parameters
from micromagnetic simulation results, i.e,
pdf of transition jitter, cross-track correlation
and partial-erasure threshold. These basic
parameters are affected severely by the head/
media geometry and grain construct.
Both the pdf of transition jitter and the crosstrack correlation are derived from single pulse
simulation. An isolated transition is written on
the Voronoi media at nominal center (x = 0),
to produce a two-dimensional magnetization
m(x,z). The derivative of the averaging
magnetization m(x), normalized in unit area,
leads to the pdf of transition jitter. Cross-track
correlation was obtained by the integral of the
auto-correlation function from magnetization
m(0, z) in crosstrack direction, where x = 0
denotes the magnetization near transition
center.
Amplitude loss of read-back pulses due to
partial erasure reveals the probability of
partial erasure occurrence for closely placed
transitions. Evaluating the partial erasure
33
34
threshold is equivalent to estimating the
probability of partial erasure between
adjacent transitions. We first derived an
analytical approach to estimate the remaining
magnetization after partial erasure occurs.
We further used micromagnetic simulation
to model two closely placed transitions and
observe the magnetization after partial
erasure. Ideally, these magnetization values (at
x=d/2) found from micromagnetic simulation
should be equivalent with the one derived
based on our analytical expression. Figure 1
shows that the estimated partial erasure (PE)
threshold for the proposed 1 Tb/in2 design is
around 2.5 nm.
to single bit length. At the receiving side,
an iterative receiver (i.e., turbo equalizer) is
employed, which consists of a noise-predictive
(NP) BCJR-based channel detector and an
outer LDPC decoder. The NP BCJR detector
employs tentative hard estimates retrieved
from survivor paths in the channel trellis to
predict noise elements. Since LDPC decoding
itself is an iterative process, the number of
local iterations within the LDPC decoder per
overall iteration is set to 5; while all simulation
results in Figure 2 represent BER results
obtained at the 10th overall iteration. The
signal-to-noise ratio (SNR) is defined as,
(ii) Read channel simulation
Figure 2 depicts the simulated BER results of
a high-rate LDPC code transmitted over the
microtrack modeled 1 Tb/in2 perpendicular
recording channel. The channel density is
1.2 and a 5-tap generalized partial response
(GPR) target is designed based on the
modeled readback pulses, which is given by
{1.0, 0.87293, 0.36193, 0.093539, -0.017825}.
The number of microtracks is 6 with crosstrack correlation measured as 5.18 nm in the
micromagnetic simulation. The LDPC code is
based on a random parity-check matrix with
column weight 3 and codeword length 4096.
The transition jitter is J=12% as compared
RIGHT
Figure 1. Estimation
of partial erasure
threshold L.
Figure 2. BER
performance of
turbo equalizers over
microtrack modeled 1
Tb/In2 perpendicular
recording channels.
Figure 1.
where Vop is the base-to-peak value of isolated
transition response and
L=4 is the oversampling rate,
is the
noise variance in the user bandwidth, and
R=8/9 is the code rate. It is shown that the
turbo equalizer with the number of NP filter
taps Q=1 performs slightly better than the
conventional BCJR detector. However, by
increasing the value of Q to Q=2, the NP turbo
equalizer achieves a performance gain of 2
dB at BER of 10-5 while maintaining the same
Figure 2.
trellis size. Hence, the NP turbo equalizer is
shown to be a viable approach for tackling
with jitter and partial-erasure in 1 Tb/In2
perpendicular recording systems.
on micromagnetic and electromagnetic
simulation will be integrated into the SWRC
platform.
(iii) Software recording channel
To facilitate BER testing on practical magnetic
recording systems, we have developed a
software recording channel (SWRC) at DSI,
which is a modular simulation platform with
a series of “boxes”, or “categories” into which
researchers in different areas of the channel
can insert their modules to be tested. The
six categories of modules within the SWRC
are: encoder modules, channel modules,
preprocessor modules, equalizer/timing
recovery modules, detector modules and
decoder modules, as shown in Figure 3.
The software channel serves as the backbone
platform in DSI into which our research in
different areas of signal generation and
processing can be deposited, stored, and
tested. The outcomes from the in-house
projects on read channel design and
magnetic recording signal generation based
35
The SWRC platform can run on “distributed
computing nodes”, where the computational
nodes are distributed across a local area
network (LAN). At DSI we are developing our
computing hardware infrastructure to increase
the power of our platform and reduce the time
to generate the results. Another benefit of
distributed computing is that simulations can
run to lower BER checking for the existence of
error-floors that might be lurking below our
field of view, if single nodes are used.
The SWRC platform is also connected through
the LAN to the spin-stand in our cleanroom.
Our algorithms can thus be tested on real
wave-forms. This also combines the channels
work more closely with the work in heads
and media and allows channels to be more
quickly and easily tested when the newest
head and media become available. This also
helps to minimize the human presence in the
cleanroom and increases the life-span of our
heads.
Figure 3.
LEFT
Figure 3. Block diagram
of the generic software
recording channel. The
green boxes detail some
previous and ongoing
research in different
areas in DSI.
36
network storage
technology division
A Dynamic Disk-based Tape Emulated on
Demand Backup Storage Service Using
ONFIG II Testbed
Storage can be seen as a commodity
needed by modern small, medium and
large enterprises, with increasing demand
due to exponential growth in volume of
corporate data. One common practice of most
enterprises is purchasing storage with large
capacity at the beginning. When storage is to
be used up, another large storage is added
to fulfill the requirements. Such practice has
two drawbacks. Firstly, manual involvement
is necessary to monitor the usage of storage
resources. Secondly, storage is largely
underutilized when it is initially purchased.
To reduce the manual involvement and
storage waste in enterprises, a new model
of storage provision is desirous. On-demand
storage is a good candidature to offer
storage as a commodity according to users’
requirement. It allows customers to buy
RIGHT
Figure 1. Architecture
for on-demand storage
solution with URM.
Figure 1.
storage based on current needs rather than
building out for maximum storage capacity.
Storage resources will be made available on an
as needed basis, and billed accordingly. With
on-demand storage service, the customer
only needs to pay for what he uses, instead of
wasting money by retaining poorly utilized
systems.
This project proposes to deliver an on-demand
data backup and recovery service with diskbased tape emulated storage in distributed
environment. High performance data
backup and recovery are always attractive to
customers as it can better support disaster
recovery and business continuance. By taking
advantage of fast disk storage system and
high speed optical network, users will have
the means to attain high performance and
have flexible configuration at an affordable
cost based on a pay-per-use model as shown
in Figure 1.
In a comprehensive network environment,
multiple resources (storage capacity, network
bandwidth, etc.) are separately managed in
different domains. Service providers have to
maintain separate management modules
and put separate efforts to monitor, control
and administrate these resources, leading to
management complexity and redundancy.
An ideal management model should cover
different domains and manage the unified
resources simultaneously, thus brings
about the necessity for a Unified Resource
Management (URM).
for optical network bandwidth setup and
control via Gigabit Ethernet over ONFIG II
testbed.
In this project we designed and developed
a centralized resource management module
(Figure 2) to control, monitor and allocate
storage and network resources dynamically, a
virtual tape server cluster with the integration
of storage networking protocols mechanism
Further work into this project will be carried
out together with ONFIG II testbed team in
order to facilitate deployment in the real
environment. Local telecom service providers
and storage system manufacturers will be
engaged for collaborative work.
Figure 2.
37
The outcome of this project can be well
applied to network service and storage utility
service providers in the market. As there is
a push for Singapore to be the hub for data
backup and recovery service for other parts
of the world, this project is the platform
by which capability may be demonstrated
through leveraging on testbedding facilities in
Fusionopolis.
LEFT
Figure 2. Modules for
On-demand Storage
Services.
38
network storage technology division
Consumer Electronics Research @ DSI
The ever-evolving digital world with the
proliferation of broadband and wireless hub
has accelerated the pace of technological
innovation in consumer electronics.
The emerging consumer electronics trends
include home entertainment interoperability
with high quality multimedia digital
experience, seamless connectivity and
integration of consumer electronics devices
and the convergence of media and data, as
shown in Figure 1.
These trends indicate that the consumer
electronics market is in a rapid evolution
phase with high level of competition to roll
RIGHT
Figure1. New
convergence in
consumer electronics.
Figure 1.
out unique and differentiated products that
support emerging technologies.
DSI has taken the initial step onto the research
bandwagon on consumer electronics, backed
by the immense expertise in data storage
research.
The key research areas are focusing on
home digital devices interoperability, DLNA
protocol implementation for AV browsing and
streaming, integration between disparate CE
devices, and employment of background IP
in WSTP (wireless storage transport protocol)
for video streaming via WiDrive as shown in
Figure 2.
DSI is currently developing a home media
server which is essentially an advanced
Set-Top-Box with broadband connectivity,
Hard Disk Drive (HDD) based storage that
acts as a content aggregator and is capable
of subsequently redistributing the digitized
media (digital photos, audio, home movies,
broadcast TV) within the home network to
other clients or media adapters.
to Browse AV-Content of WiDrive using DLNA
protocol, playing slide-show, AV-content from
WiDrive to PDA, and surveillance system using
wireless digital camera.
The home media server architecture
featured in the development is capable of
implementing functions such as automated
discovery of Wireless HDD (WiDrive),
streaming of audio/HD-Video from WiDrive
to HD-TV through the server, allowing PDA
39
Audio/Video content from various sources can
be streamed to other clients (media players,
PC, PDA) around the home for real-time, time
shifted or on-demand playback. The home
media server platform can also function as a
wired or wireless broadband router to provide
broadband connectivity to other clients.
Unlike the PC, the home media server is a
consumer friendly platform where the user
can access all the functions through a simple
remote control.
Figure 2.
LEFT
Figure 2. DSI home
media server.
40
optical materials &
systems division
Development of High Density Phase
Change Random Access Memory
(PCRAM)
(a) Thickness dependent nano-
crystallization in Ge2Sb2Te5 films and
its effect on PCRAM
Phase change random access memory
(PCRAM) is considered as the best candidate
for the new generation of non-volatile
memory (NVM). PCRAM uses the reversible
structural phase change in chalcogenide
phase change materials, which in turn
changes the electrical resistivity of the
material as the data storage mechanism.
Besides its high-performance NVM natures,
the most important advantage of PCRAM
over other NVMs is its high scaling potential.
Currently, the working unit area of PCRAM is
in the order of nano-scale. On the nano-scale,
extreme dimensional and nano-structural
constraints and the large proportion of
interfaces will cause the deviation of the phase
change behavior from that of the bulk. Hence
an in-depth understanding of nano phase
change and the related issues has become
more important. This work investigates the
nano-crystallization mechanisms in ultra-thin
Ge2Sb2Te5 phase change material by in-situ
resistance measurement and studies their
impact on PCRAM devices.
The in-situ resistance measurement is
an effective method to investigate the
crystallization process of phase change
material. In our experiment, the sample was
uniformly heated by a thermal chuck system.
Thin Ge2Sb2Te5 films with different thickness
and sandwiched by 50 nm ZnS-SiO2 films
were prepared by sputtering. For resistance
measurement, two electrodes were patterned
and deposited with 100 nm TiW.
The heating rate in PCRAM cells is as high as
109 ºC/s and fcc is the only state which can be
achieved in such a high speed, the dominant
crystalline state in PCRAM cells is believed to
be fcc state. The crystallization temperature
(Tc) to fcc state is lower than 200 ºC,
therefore, the exothermal measurement
(ETTM) was therefore carried from 21 ºC to
220 ºC at different heating rate. Figures 1 (a)
and (b) show the resistivity dependence on
temperature for the samples with 5 nm and
30nm Ge2Sb2Te5 films, respectively.
The heating rate was changed from
0.5 ºC/min, 1 ºC/min, 3 ºC/min, 10 ºC/min to
20 ºC/min, respectively. Since the
crystallization process can be characterized
by the steep resistivity change, it is obvious
that the crystallization slope in 30 nm thin
film is much steeper than that of 5nm thin
film at the same heating rate. It indicates that
a slower crystallization speed was happened
in thinner phase change films. Furthermore, it
can be noticed that the crystallization process
is delayed when the heating rate increases,
which means the crystallization temperature
increases with the increasing of the heating
rate in the films with the same thickness.
However the delay of crystallization between
0.5 ºC/min and 20 ºC/min in 5 nm film is much
less than that in 30 nm film as shown in
Figure 1.
In isothermal resistance measurement (ITTM),
100 nm to 3.5 nm thick Ge2Sb2Te5 samples
were isothermally heated at 143.5 ºC.
The resistivity verses time for different films is
shown in Figure 2. A characterized parameter
in isothermal measurement is the incubation
time (τ), which is determined by the time
before sharp transition. It can be seen that τ
has increased from 102s at 100 nm to 103s at
10nm and finally to about 104s at 3.5 nm. It is
obvious that τ is much larger for samples with
Ge2Sb2Te5 films thinner than 20 nm, which is
in good agreement with the value measured
by ETTM. In addition, the transition time from
the highest to lowest resistivity is increased
from 500 s to longer than 105s as the thickness
decreases from 100 nm to 3.5 nm. It indicates
that the crystallization speed decreases when
the film thickness is decreased.
Activation energy for crystallization can be
derived by Kissinger plot based on formula:
where, R is the heating rate, Tx is the
To better understand the crystallization
process, Tc of Ge2Sb2Te5 with different
thickness and different heating rates were
systematically studied. Ge2Sb2Te5 thin
films with thickness of 5nm to 30nm were
fabricated. They were annealed at different
heating rates. Tc, which is determined by the
minimum in the first derivative obtained by
(dR / dT), are listed in Table 1. It can be seen
that, for the films less than 20 nm thick, Tc
increases when the film thickness is reduced.
It can be seen as well that Tc increases with the
increasing heating rate.
Table 1.
R (ºC/
min)
5
nm
10
nm
15
nm
20
nm
30
nm
0.5
157
149
141
138
138
1
159
153
147
142
142
3
164
157
152
148
148
10
166
160
155
154
154
20
170
164
160
157
157
Figure 1.
1.0E+00
41
1.0E+00
30 nm
5 nm
0.5 deg/min
1 deg/min
1.0E-01
3 deg/min
R (ohm/cm)
R (ohm/cm)
1.0E-01
1.0E-02
0.5 deg/min
1 deg/min
1.0E-03
10 deg/min
20 deg/min
1.0E-02
3 deg/min
10 deg/min
20 deg/min
1.0E-04
120
LEFT
Table 1. Crystallization
Temperature (º C) by
ETTM
1.0E-03
130
140
150
160
T (C)
170
180
190
120
130
140
150
160
T (C)
170
180
190
LEFT
Figure 1. ETTM of
Ge2Sb2Te5 thin films at
different heating rates,
(a) 5 nm, (b) 30 nm.
42
optical materials & systems division
crystallization temperature at heating rate
R, and KB is the Boltzmann’s constant. Based
on the Tx determined previously, Kissinger
plot for each sample is plotted in Figure 3.
The slope of each line corresponds to the
activation energy Ea and a good relationship
is obtained between Ln(R/Tx2) and (R/Tx). The
Ea estimated from the slopes of the Kissinger
plots increased from ~ 2.86 eV in 20nm film,
3.11eV in 15 nm film and 4.05 eV in 10nm film
to 4.66 eV in films of 5nm. A linear relationship
was found between Ln (Tx) and thickness d as
plotted in Figure 4.
Since the crystallization Ea is directly related
to Tc, it can be used to explain the increasing
Tc in ultra-thin films. A model, which includes
a specific interfacial energy, proposed by
Zacharias can be used to explain this thickness
dependent Ea and Tc. The key point of the
model is to introduce an effective interface
energy that interpolates between the true
oxide/crystalline interface energy and the true
amorphous/crystalline interface energy using
an order parameter varying continuously with
interface spacing. The dependence between
interface energy and spacing is due to an
additional spacing l which corresponds to
The relationship between l and nucleation
barrier is realized by taking into account of
different interface energies and materials.
According to the model, the phenomenon
that an exponential increase of the
crystallization temperature with decreasing
layer thickness has been derived14):
where γac, γoc, and γoa are defined as the
interfacial free energies per unit area between
amorphous (a) and crystalline (c) phases (a/c),
between oxide material o and crystalline (c)
semiconductor phase (o/c), and between
oxide material o and amorphous (a) phase
(o/a), respectively, lo is an average screening
or bonding length related to the range of
interatomic forces typical for materials o and c.
Figure 3.
26
26.5
27
27.5
28
28.5
-8
1.0E+00
R/Tx
-9
1.0E-01
-10
+
ln(R/(Tx -Tx))
Figure 3. ETTM Kissinger
plots of thin Ge2Sb2Te5
films.
Figure 2.
R (ohm/cm)
RIGHT
Figure 2. Resistivity
verses. Time for
Ge2Sb2Te5 heated at
143.5 ºC.
a finite separation of the nucleus from the
oxide boundaries. When the film thickness
is very large, l can be ignored and the classic
nucleation theory is applicable. However,
when the thickness is close to 20 nm, the
effect of l is more obvious which increases the
nucleation barrier.
1.0E-02
1.0E-03
1.0E-04
100
3.5nm
5nm
10nm
20nm
30nm
100nm
1000
10000
t (s)
-11
-12
-13
15nm
30nm
100000
-14
20nm
15nm
10nm
5nm
The exponential relationship between Tx and
film thickness in Eq. 2 is in good agreement
with the measured Tc and film thickness as
shown in Figure 4.
where, t is time, n is the Avrami coefficient, k
is an effective rate constant. v is the frequency
factor, EA is activation energy, T is the absolute
temperature, and KB is the boltzmann
constant.
Other possible reasons for the increasing Tx
and Ea may be the inhomogeneous strain
which may increase with decreasing layer
thickness because of (i) increase of surface/
volume ratio with decreasing nano-crystal
size, (ii) difference in thermal expansion
coefficient of Ge2Sb2Te5 and dielectric, (iii)
volume shrinkage associated with the
transformation of amorphous into more dense
crystalline material.
In JMA (Johnson-Mehl-Avrami) model, a 3D
nucleation and growth process was proposed.
The volume fraction of the transformed
materials x(t) can be described by JMA
equation:
Figure 4.
Figure 5 shows the plots of ln(-ln(1-x)) against
ln t for each sample. A good linear relationship
was obtained in each case. The slopes of these
plots shown in Figure 5 are corresponded
to Avrami coefficients and indicate different
crystallization mechanisms. Normally, when
n > 2.5, during the crystallization, all shapes
grow from small dimensions with increasing
nucleation rate; while 1.5 < n < 2.5 means
all shapes grow from small dimensions with
decreasing nucleation rate; if 1 < n < 1.5, it
means growth of particles of appreciable
initial volume; n < 1 corresponds to growth
process like a needles and plates of finite long
dimensions during crystallization.
Figure 5.
6.09
3
6.08
2
LEFT
Figure 4. Crystallization
temperature verses
Ge2Sb2Te5 thickness at a
heating rate of 3 ºC/min.
1
ln(-ln(1-x))
6.07
Ln(Tx)
43
6.06
Figure 5. Avarami plots
of ultra-thin Ge2Sb2Te5
films.
0
-1
30nm
6.05
-2
20nm
15nm
6.04
-3
6.03
10nm
5nm
-4
0
5
10
15
thickness (nm)
20
25
4
5
6
7
Int
8
9
44
Figure 6 shows Avrami coefficient (n) verses
film thickness in thin Ge2Sb2Te5 films. It can
be seen that above 20 nm, n for Ge2Sb2Te5
films are larger than 1.5. It means that in
these crystallization processes, grain growth
occurs with nucleation. Its nucleation rate
decreases with the grain growth. When the
film was reduced to around 10 nm, the grain
only grows in parallel dimension and the
thickening of long cylinders (needles) happen.
When the thickness is reduced to 5 nm,
thickening of very large plates (e.g., after
complete edge impingement) happens.
Recently, a line-type PCRAM has attracted
great interests. This device has an ultrathin
line of phase-change material surrounded
by dielectric. Since the thin phase change
was surrounded by dielectric which has
lower thermal conductivity, line-type
PCRAM dissipates little power. Furthermore,
crystallization occurs from the edge of the
amorphous volume inwards, its performance
improves when the line length is reduced. It
can be noticed that besides the line length,
the film thickness of the phase change line
is also critical to the device performance.
When phase change line becomes very thin,
Figure 6.
Figure 7. Schematic
diagrams of
different PCRAM cell
configurations (a) Type I,
and (b) Type II.
(b) Study of geometric effect on PCRAM
Engineering PCRAM device structure is
one of the efficient approaches to reduce
programming current. In this work, we
compared PCRAM memory devices with two
different geometrical configurations. The
geometry effect on device functionalities in
terms of thermal and electrical properties was
analyzed by simulation. A 128 bits PCRAM
array integrating with CMOS transistor and
above mentioned two different devices were
fabricated and characterized, respectively.
Figures 7(a) and (b) show the schematic
diagrams of the two different PCRAM cell
configurations studied. It can be seen that
Figure 7.
1.8
n > 1.5
1.6
Avrami coefficient
RIGHT
Figure 6. Avrami
coefficient (n) verses
film thickness for thin
Ge2Sb2Te5 films.
e.g., less than 20 nm, the above mentioned
film thickness dependent crystallization will
significantly affect the device performance.
Not limited to line-type PCRAM, this thickness
dependent nano-crystallization effect will
also significantly affect any other PCRAM
devices’ performance when phase change film
thickness is reduced to 20 nm below. Hence,
the studies in this work will provide useful
guidance for the design of PCRAM devices in
these conditions.
(a)
1.4
1 < n < 1.5
1.2
1
n<1
(b)
0.8
0
10
20
Thickness (nm)
30
40
device Type I in Figure 7(a), the amount of
phase change material above the contact
area is surrounded by dielectric layer while
it is not for device Type II in Figure 7(b). The
contact interfaces are between the phase
change materials and the bottom electrode
was designed with the same size of 0.35 µm
in diameter. Ge2Sb2Te5 was used as the phase
change material, ZnS-SiO2 as the isolation and
TiW as the electrode.
Figure 8 shows the cross-sectional
temperature distribution profile after applying
same electrical pulses in the two devices with
different cell configurations, respectively. The
devices were first applied with an electrical
pulse of 0.65 V bias for 50 ns before cooling it
for the next 50ns. A thermal boundary of 27 ºC
was applied at both the top and bottom of the
structure. Ge2Sb2Te5 was initially at crystalline
state. From the temperature profiles, it can be
found that heat was confined mainly in the
phase change materials. The peak temperature
achieved in these devices can be obtained. It
showed that the peak temperature for Type I
cell was much lower than that in Type II which
was around 669 ºC. It suggests that, with the
same voltage pulse, the heat generated in
the phase change materials more efficiently
for Type II than the Type I device. For Type II
device, electrical pulse with lower voltage is
needed to melt the phase change material
above its melting temperature. The result is
in agreement with those previously reported.
In that report, constant current pulses were
applied. It was claimed that Type I device
required less current to melt phase change
than Type II device.
In the simulation, finite element method and
standard heat conduction equation were
used. The thermal properties of the device
materials were assumed to be independent
of temperature. It was also assumed that the
electrical properties of the materials in the
structure were isotropically homogeneous
and independent of temperature. Latent
heat was not considered because it is much
smaller than that of Joule heating. Simulation
studies were carried out by applying
electrical pulse with a constant voltage. Both
voltage and pulse width were varied. The
temperature distribution, the achievable
highest temperature and the location of
highest temperature point were simulated
and analysis for the two PCRAM devices,
respectively.
45
Figure 8.
LEFT
Figure 8. Temperature
distribution in PCRAM
cells with structure of
(a) Type I, and (b) Type II,
respectively.
46
When applying pulses with constant voltage,
the heating power can be defined by the
equation:
,where, P is the power, V is
the voltage across the structure and R is the
resistance of the structure. Applying pulses
with constant current, the heating power can
be defined by the equation:
,where,
P is the power, I is the current across the
structure and R is the resistance of the
structure. Due to the different layout, the
resistance R for Type I is higher than the Type
II device. Hence in the case of applying same
constant voltage pulse, the heating power
applied on Type I is lower than on Type II.
While in the case of applying same constant
current pulse, the heating power applied
on Type I is actually higher than on Type II.
As voltage power source is used in device
operation, simulation with constant voltage is
more reasonable.
Figure 10. Schematic
diagrams of PCRAM
device with structure
of (a) Type I, (b) Type II
integration with CMOS.
Figure 9 indicates the temperature history
during the electrical pulse inside the phase
change layer. It can be noticed that when
applying the same 0.65 V electrical pulse,
Type I device heated up to a lower peak
In this work, based on 0.35 µm technology,
128bits PCRAM arrays were fabricated. CMOS
transistor was integrated with PCRAM cell
as the addressing element. The PCRAM
arrays had full periphery circuit functions.
The above mentioned two different PCRAM
cell structures were implemented in the
arrays as shown in Figure 10 respectively.
The operation and characteristics of PCRAM
unit device, e.g., current-voltage (I-V) curves
and resistance-current (R-I) curves were
Figure 9.
Figure 10.
800
700
600
Temperature (C)
RIGHT
history during electrical
pulse inside the phase
change layer.
temperature due to a slower heating rate
it had compared to Type II device. If Type I
device heated up to the similar temperature
as Type II, pulse with a higher voltage value
~0.77 V was needed. The results showed that
both the bottom electrode and phase change
layer geometry and the size of the interface
between the phase change material and
the bottom electrode were the determinant
factors to the temperature profile and heat
distribution. It showed that during operation,
the bottom electrode acted as the heat sink.
Compare to Type I cell, Type II cell has a smaller
heat sink and hence a faster heating rate.
Type I 0.65V
Type II 0.65V
Type I 0.77V
(a)
70
(b)
500
400
300
200
100
0
0
10
20
30
40 50 60
Time (ns)
80
90 100
measured by a self-build testing system. The
schematic description of the experimental
setup is shown in Figure 11. In the circuit, an
electrical pulse was generated and delivered
to the PCRAM cell through a load resistor
Rload. The 50 Ω termination resistor was used
to minimize the reflections back to the pulse
generator. From Figure 11, the applied voltage
and the voltage drop on the load resistor were
measured by oscilloscope through active
probes. Hence the dynamic voltage drop
and the current passing though the PCRAM
device were observed and estimated from
oscilloscope. In Figure 11, V1 is the applied
voltage, V2 is the voltage drop on load resistor,
V1-V2 is the voltage drop on PCRAM cell.
After each programming pulse, the low field
resistance of the PCRAM device was measured
with a 0.2 V reading voltage.
varied with 5 ns, 10 ns and 20 ns, respectively.
The R-I curves showed that both of the two
cells could be RESET at short pulse as short
as 5 ns. Both figures also demonstrated that
lower RESET current was required when
the pulse width increased. It can be seen
that the RESET state resistance of Type I was
much higher than that of Type II, which was
consistent and confirmed with the simulation
result in the earlier part.
Figure 12 exhibits the R-I curve for the two
types of PCRAM devices. The starting states of
the cells were crystalline state. During RESET/
SET, the write pulse voltage was applied from
zero to a higher value. The pulse widths were
Figure 11.
47
To compare RESET currents for these two
devices, Figure 13 shows the comparison of
the two R-I curves at 5 ns pulse width. The
RESET resistances were normalized. It can be
seen that with a low programming current
of about 0.3 mA, Type II PCRAM cell started
the resistance change from low to high, while
Type I PCRAM cell started its resistance change
with a higher current of about 0.5 mA. The
experimental result is consistent with the
previous simulation result. Although Type
II cell required lower current to start phase
change, it needed a higher current to switch
from SET state to fully RESET state than the
LEFT
Figure 11. Schematic
description of the
experimental setup.
48
device with the Type I structure. The results
suggested that Type II device spanned a wider
current range to switch from crystalline state
to fully amorphous state.
To explain this phenomenon, a possible
model is proposed. The amorphous phase
distribution inside phase change layer is
schematically plotted in Figure 14 for the two
devices, respectively. The starting phase state
of PCL was in crystalline state. In Figure 14,
it is assumed that the total resistance value
of PCRAM cell is the sum of the crystalline
state resistance Rc and amorphous state
resistance Ra in series. Since the heat was
mostly confined within the PCL channel by
the dielectric layer in Type I device, the phase
change material inside the PCL channel was
heated up and reached first above its melting
temperature and became amorphous state as
RIGHT
Figure 12. R-I curves for
PCRAM with (a) Type I
and (b) Type II.
Figure 12.
shown in Figure 14 (a). The horizontal length
of the amorphous phase change area was
similar to the width of the channel. Hence,
the Ra in Type I device was mostly determined
by the thickness of the phase change media
in amorphous state inside the channel. The
variation of the amorphous phase change
film thickness inside the channel is not big.
It exhibited that Type I device required less
current range to change from SET state to fully
RESET state.
In Type II device, the phase change film on top
of the interface between bottom electrode
was heat up fast and first reached its melting
temperature to become amorphous state.
However, there was no heat confinement
structure sandwiched the phase change
layer as in Type I device. The heat generated
in the phase change layer would be spread
to the side on top of the interface between
electrode and PCL. Hence, the diameter of the
sphere shape of amorphous phase change
media could be much larger than the channel
width. Therefore the Ra in Type II device was
not only determined by the thickness of
the amorphous phase change media, but
also the diameter of the amorphous sphere.
From Figure 14(b), it can be noted that the
variation of the amorphous phase change film
thickness on top of the interface of electrode
and PCL varies significantly. The thickness
of the amorphous phase change film was
smaller at the edge of the interface between
electrode and PCL than that on top of the
center interface. Hence, the total resistance
value at the edge was Rc2 + Ra2, which was
lower than that on top of the center interface
Rc1 + Ra2. Therefore, Type II device had a slower
slope from SET state to fully RESET state, and it
covered a larger current range to change from
SET state to fully RESET state.
Figure 13.
49
LEFT
Figure 13. Comparison
of R-I curves for PCRAM
with two structures at
5ns pulse width.
Figure 14. Schematic of
the possible amorphous
phase distribution
in PCL for PCRAM
with (a) Type I and (b)
Type II (shaded area is
amorphous state).
Figure 14.
(a)
(b)
50
Research on Heat Assisted Magnetic
Recording
Heat assisted magnetic recording (HAMR)
or hybrid recording which is a promising
technique, can assist the magnetic head
to increase the writability on the higher
coercivity media. Though many short-term
alternatives such as perpendicular media,
patterned media, were proposed to push
the limitation further, all these alternatives,
however, will ultimately have to resort to
HAMR to achieve appropriate writability.
DSI has built up considerable amounts of
capability in HAMR technology. A far-field
HAMR platform based on the commercialized
spin-stand has been successfully set up. In
addtion, a series of HAMR experiments and
researches have been carried out with this
platform. Currently, two key components for
HAMR: high temperature lubricant and nearfield optical head are the focus.
RIGHT
Figure1. (a) Schematic of
optical path for HAMR
platform. (b) Photo of
HAMR platform
Figure 1(a).
Figure 1(b).
HAMR
The proposal of the HAMR technology is to
store the data with recording density beyond
1 Tb/in2. In this system, the heated area size
should be less than 40 nm, which can be
obtained by using near-field optics only.
However, for some fundamental researches
and functional demonstration, a HAMR
platform with far-field optics is a useful tool.
Far field HAMR platform consists of magnetic
recording spinstand and far-field optical
energy delivery system (optical heater), and
both magnetic write head and optical system
are set on the oppose sides of the media. The
schematic of the optical system and the photo
of the HAMR platform built in our laboratory
is shown in Figure 1(a). The optical system is
composed of 5 main optical paths to fulfill the
functions of laser delivery, illumination of the
magnetic head, coarse alignment, and fine
alignment of laser spot with magnetic head
and focusing error signal path for servo.
The optical system is put on a 2D translation
stage with tens of nanometers resolution
so as to precisely align the optical spot with
magnetic head. Additionally, the objective
lens functioned as focusing laser on the media
and imaging laser spot and magnetic head,
is mounted on the pizeo-actuated stage with
nano-meter resolution to achieve precise
focusing on the rotating disc. The picture of
the platform is shown in Figure 1(b).
Figure 2 shows the captured pictures of
dynamic alignments between the optical spot
and magnetic writing head (60 Gb/in2) with
the rotation speed of 2000 rpm.
of newly-synthesized high temperature
lubricant for HAMR applications; (iv) thermal
performance validation of the media.
This HAMR platform has the following
functions: (i) generic HAMR function
demonstrations, track thermal profile
mapping and track cross-talk with laser
shining; (ii) head disk interface researches
including slider fly stability, slider deformation
and head protrusion etc.; (iii) evaluation
51
HAMR Function Demonstration
The most obvious symbol of the HAMR
is that the data can be stored with lower
writing current assisted by a laser beam.
With the platform and longitudinal magnetic
media [Galss/CrMo(10 nm)/CoCr(3 nm)/
CoCrPtB(20 nm)/C(4 nm), which is just served
for demonstration and far from thermally
optimized in structure for HAMR], the readout
signals from recorded disk with/without laser
assistance are shown in Figure 2. It is very clear
that the laser has caused the reduction of the
media’s coercivity.
It is desirable to depict the actual spatial
thermal distribution for further researches.
Unfortunately, such localized thermal field
(less than 1 um) is still immeasurable directly
Figure 2.
LEFT
Figure 2. Captured
dynamic alignment of
laser spot with writing
pole of magnetic head
Figure 3. Readout
signals with/without
laser. Writing current: 9
mA; Laser power: 9 mw;
Rotation speed: 2000
pm; Writing speed: 30
MHz.
Figure 3.
52
by the state-of-art IR camera. However, we
have another option to acquire the locally
averaged temperature by combining the write
current saturation curve at certain laser power
and the media magnetic-thermal dependence,
and then deduce the temperature at this
certain laser power. By repeating this process,
the relationship between the track average
temperature and the applied laser power
can be reconstructed. It’s noted that the
temperature achieved by this way is actually
result of averaged effect manifested by the
media properties. The temperature value
is an estimated value, but it can be a good
reference.
To validate the platform functions and
understand the difference between HAMR
recording and conventional recording, series
of experiments are implemented. Several
typical parameters, e.g., writing current
RIGHT
Figure 4. Dependences
of coercivity (Hc) and
remanent magnetization
(Mr) on the temperature.
Figure 4.
Figure 5. Write current
saturation curves with
different laser power.
Figure 5.
saturation curve, track profile and signal
to noise ratio (SNR) are selected to make a
comparison between normal and heated
recording environment.
The media coercivity at room temperature
is around 2800 Oe, and its dependence on
the temperature is measured with vibrating
sample magnetometer (VSM) as shown in
Figure 4. Figure 5 shows the measurement
results of the write current saturation curves
with laser power varying from 7.1 mW under
the rotation speed of 2000 rpm (the vertical
axis of the Figure 5 is track average amplitude
(TAA)]. The gradual shift of the saturation
current with increase of the laser power
results from the coercivity reduction of the
media which stemming from the localized
net temperature rising of absorption of laser
power.
Just as abovementioned, by combining the
temperature dependence of media coercivity
and the net shift of the saturation curve, the
net temperature increase can be estimated.
Figure 6 is the dependence of the media
coercivity and achievable temperature on the
laser power. The maximum temperature rising
in this experiment is 140 °C. The track profiles
at different laser powers and fixed write
current of 10 mA are shown in Figure 7.
One of interesting phenomena is TAA reaches
the maximum at laser power of 9.5 mW.
Further increase of the laser power does
not lead to further increase of TAA.
On the contrary, slight decrease is witnessed.
Qualitatively, this is attributed to two factors:
one is that 9.5 mW laser power has pushed the
media to the saturation, so further increase
cannot bring further increase of the TAA;
second is that higher laser power causes
Figure 6.
53
LEFT
Figure 6. Dependence of
the media coercivity and
achievable temperature
on the laser power.
Figure 7. Track profiles
at different laser powers
with write current of
10 mA.
Figure 7.
54
the higher temperature change, due to unoptimized media thermal structure, some
written grains in the transition area may flip
over during the duration of cooling down,
which can be further verified from the readout
signal with longer transition length (the tilt
shoulder at the trailing edge of the readout
signal in Figure 8 shows the longer transition
length).
Another important parameter evaluation
demonstrated here is the effect of laser
power on SNR. The test results of the SNR for
the situations when writing with the same
RIGHT
Figure 8. Response
readout signal at
laser power of 9.5 mW.
rotation speed but at different laser powers
and different writing currents are shown in
Figure 9 and Figure 10. For fixed write current
and writing speed, the SNR increases with
the laser power, but there is optimal power at
which the SNR reaches the maximum value.
For fixed laser power, however, SNR increases
with the writing current until 10 mA. Beyond
that, the increase of SNR is not so obvious in
the tested write current range. It implies that
the match among the laser power, rotation
speed, and writing current are necessary to
have optimal performance.
Figure 8.
Figure 9. SNR with
different laser power at
writing current of 10mA.
Figure 10. SNR with
different writing current
at laser powers of
9.5 mW. The spindle
rotation speed is
2000 rpm.
Figure 9.
Figure 10.
10mA, with laser
9.5mw
12mw
7mw
11mA, with laser
12mA, with laser
9mA, with laser
8mA, with laser
0mw
10mA, with laser
Laser power:
9.5mw
Rotation speed:
2000rpm
Lubricant Study for HAMR Media
is not permanent. TOF-SIMS image shows
clearly that the laser irradiation has caused
the lubricant situation changed. This further
verifies the importance of the synthesis of new
high-temperature lubricant and optimization
of thermal structure of the media, since
the optimal design may obtain the fast
cooling speed but still keep the reasonable
temperature rise speed and reduce the burden
for desire of high-temperature lubricant.
The platform can play a good role in lubricant
study for HAMR application as well since
it provides a spatial and temporal high
temperature environment. As an example, the
thermal performance of the normal Z-DOL
lubricant is preliminarily evaluated with the
platform by irradiation of the laser. After this
dynamic irradiation process, the imaging and
the component analysis at irradiated zone are
conducted by optical surface analyzer (OSA)
immediately, as shown in Figure 11(a), and
time of flight secondary ion mass spectrometer
(TOF-SIMS), as shown in Figure 11(b).
The observation results show that the
irradiated parts have changed gradually as
the laser power increase. Nevertheless, the
change can only be observed at irradiated part
with power of 16.5 mw after two days. This
implies that at low temperature, the change
55
Evaluation of the Thermal Effect of the
Heated Media on Slider
When media rotates at high speed, it is
impossible to map the thermal distributions
of the media and slider directly in HAMR
environment. Instead, the average
temperature changes of the media and slider
are adopted to evaluate the thermal effects.
Firstly, the reader sensor can be calibrated to
Mark made before laser irradiation
Figure 11(a).
16.5mw
14.1mw
11.8mw
9.4mw
Mark made before laser irradiation
Figure 11(b).
LEFT
Figure 11. (a) OSA image
and (b) TOP-SIMS image
of the Z-DOL lubricant
after laser irradiation
with the platform.
56
obtain the dependence of sensor resistance
on slider temperature; secondly, with HAMR
platform, the slider is shined with laser
that passing through a glass substrate to
investigate the impacts of laser on the head
by varying the laser power and rotation speed;
thirdly, the glass substrate is replaced with a
single side glass magnetic disk to study the
thermal effect of the locally heated media on
the head at heat assisted recording state.
Due to that the read sensor is used as
temperature sensor, the slider temperature
change measured in this study is the read
head area temperature. In our experiment, the
reader sensor is calibrated by resting the slider
closely against a big thermal electric cell (TEC)
with temperature control resolution of 0.01 ºC.
The same batch of GMR magnetic head with
60 Gb/in2 is used in the experiments. The
slider fly height of around 11 nm is tested
under the experimental conditions by flying
height tester.
RIGHT
Figure 12. Dependences
of the reader sensor’s
resistance on the
temperature.
Figure 12.
Figure 13. Relationships
between slider
temperature and laser
power at different
rotation speeds.
Figure 13.
With careful calibration, the dependences of
the three reader sensor’s resistances on the
temperatures are shown in Figure 12.
The linear relationships are verified within the
interested measurement range for all tested
reader sensors, and the average slope of the
curves is around 0.044 Ω/ºC.
The investigation of the laser absorption
effect on the slider is carried out by focusing
the laser on the magnetic write head gap
through a glass substrate in the platform
and monitoring the reader sensor resistance
change at different rotation speeds. Figure 13
shows the relationships between the slider
temperature and the laser power at rotation
speed of 0 rpm (slider rests on the glass disk),
2000 rpm and 3000 rpm respectively. In the
case of slider resting on the glass disk, the
maximum slider temperature change of
28.5 ºC is obtained at the laser power of
16 mW. At the rotation speeds of 2000 rpm
and 3000 rpm, the temperature changes
are almost the same and the maximum
temperature change is around 15 ºC at the
same laser power. It is obvious that the air
flow has carried some heat away and the
slider temperature net rise gets reduced. It
proves that the cooling effects at both rotation
speeds are almost the same. At stationary
status, the slider contacts the glass substrate
directly. As the result of the poor thermal
conductivity of the glass and static air layer
surround the slider, the thermal energy
of the slider is not readily dissipated into
surrounding environment. While at high speed
rotation states, the slider is flying over the
substrate, and the high speed air flow carries
considerable amount of thermal energy
away from the slider. Therefore, the slider
temperature rise at high speed rotation state
is much less than that at stationary status.
Figure 14 shows the temperature changes of
locally heated magnetic disk and slider with
the incident laser powers at different rotation
speeds. The disk temperature increases with
the increase of laser power, but reduces
with the increase of rotation speed at same
laser power. Higher rotation speed implies
short laser radiation time, and thus lower net
temperature increase is expected. The slider
temperature changes have the same trend
with that of the disk. The maximum slider
temperature change of 3.5 ºC is obtained at
the disk temperature change of 85 ºC (2000
rpm) in our experiment condition. Due to
the existence of the finite light transmission
of the media which is less than 3% at used
wavelength of 405 nm, and with consideration
of the results in Figure 12, the maximum laser
power passed through the disk can only cause
Figure 14(a).
Figure 14(b).
57
LEFT
changes of (a) magnetic
disk and (b) slider with
different laser powers at
different rotation speeds
(the lowest curve is the
temperature change
caused by transmitted
laser).
58
around 0.3 ºC slider temperature rise for the
maximum incident laser power. Therefore
most of temperature increase of the slider is
contributed by the thermal radiation of the
locally heated media (magnetic recording
layer). The experimental results at
2000 rpm and 3000 rpm also show that the
slider temperature rise is about 3~4.5% of
the disk temperature rise. If it holds true
and if the disk is heated to 400 ºC, the slider
temperature rise should be less than 20 ºC.
However, if the much smaller laser spot size
in actual near field configuration than that
in this experiment is taken into account, the
actual temperature rise caused by heated disk
radiation should be much less than 20 ºC.
To prove that the slider net temperature rise is
the result of the radiation of the locally heated
media, a simulation model is built.
RIGHT
Figure 15. Cross track
temperature distribution
of the media
Figure 15.
Figure 16. Read sensor
temperature change.
Figure 16.
By assuming the measured thermal
distribution of the heated media as shown in
Figure 15 (indirectly measured results) as the
heat source, and the height for this simulation
is the set as the experimental value, 10 nm,
the resulting net temperature rise on the slider
based on this model are shown in Figure16.
There is very good agreement between
simulation results and the experimental
results.
Due to the temperature change in the
interface area, the slider flying height will be
affected. In order to study the thermal effect
on the stability of slider flight and lubricant
interaction at the head/disk interface in HAMR
environment, a modulated laser is deflected
to radiate the rotating magnetic media and a
laser doppler vibratometer (LDV) is attached
to the platform to monitor the slider vibration
as schematically shown in Figure 17. The slider
responses in frequency domain at different
laser modulation frequencies are shown in
Figure 18. At lower frequency, the response
amplitude is larger. Under this experiment
condition, around 100 ºC of the locally heated
media temperature change is estimated based
on the abovementioned techniques.
The maximum vibration amplitude of
0.19 nm is obtained at modulation frequency
of 130 kHz based on the LDV sensitivity of
50 nm/V. Figure 19 shows the slider responses
at different laser power for 170 kHz laser
modulation frequency. As the laser power
increases, the response amplitudes increase.
In order to verify that the vibration is caused
by locally heated media, a glass substrate
without recording material is used in same
experiment, but there is no vibration response
detected.
59
The effect of laser irradiation on lubricant
transfer using different lubricants was studied
on this setup. By using the lubricated media
without bonded components, the lubricant
transfer was detected and identified under
slider flying conditions with and without
laser irradiation. Lubricant interaction with
slider and media surfaces was identified with
LDV. Specifically, two peaks of resonance
LEFT
Figure17. Schematic
for lubricant pick-up
experiments.
Figure 17.
Figure 18. LDV
responses at different
laser modulation
frequencies (laser
power: 35 mw).
Figure 19. LDV
responses at different
laser powers.
Figure 18.
Figure 19.
60
frequencies in the LDV spectrum were found
to correlate with the lubricant interaction
at the head-disk interface, (as shown in
Figure 20). A simple model indicated that
mobile lubricant molecules undergo three
types of interactions with slider and media
surfaces. The experimental results reveal
that the localized flash heating by a focused
laser beam does not accelerate the lubricant
transfer to slider. The mobility of lubricant
molecules also affects lubricant transfer to
slider surface but not directly corresponding
to lubricant transfer.
For HAMR media, lubricant is required to
withstand an intermitted temperature
changes from room temperature to the range
of 400 ~ 650 °C in a few nanoseconds which
will cause the desorption and decomposition
for normally used lubricant moleclues.
Unfortunately, available commercial lubricant
is not suitable for working at temperature
beyond 300 ºC, although lubricant additives,
e.g., X-1P1, have been used to provide good
head disk interface protection in conjunction
RIGHT
Figure 20. LDV spectra
of a slider flying on-track
on 1.2nm Lube-1 at
different rotating speed.
Figure 20.
with Z-type PFPE lubricants for current
generation of the hard disk recording media.
Not only HAMR media but also near-contactor contact-recording has put more stress
on the thermal stability and durability of
the lubricants. Thermal stability studies on
lubricants that currently used in hard disks
have been done by many people. It was
found that decomposition occurs when the
temperature is over 327 ºC and decomposition
kinetics on the a-CHx surface are insensitive
to lubricant end groups, lubricant molecular
weight, and lubricant thickness. Typical liquid
lubricants can be completely removed in less
than 1000 laser shots. The lubricant loss is
due to evaporation for low molecular weight
Z-dols and is initiated by thermal oxidative
decomposition for high molecular weight
Z-dols.
As an attempt to achieve improved thermal
stability, a novel lubricant Lube-1 was
developed in our lab to allow for application to
HAMR media. Appropriate molecular weight
and functional end groups were considered
for lubricant molecular design and synthesis in
our work. The uniformity of lubricant film on
the magnetic media is important and affected
by the initial uniformity of as-deposited film,
which controls bonding ratio and uniformity
for bonding sites. Figure 21 shows the OSA
images for commercial lubricant and Lube-1.
The film thickness for both Z-dol and Lube-1
is about 1.2 nm. All the films were deposited
under same conditions. It is obvious that
the uniformity for Lube-1 film is better than
commercial lubricant.
deposited on the magnetic media. The spot
size of laser beam is about 550 nm. Media
rotating speed is 2000 rpm. The focused laser
beam with different output laser power (10
mW, 13 mW, 16.6 mW, 20 mW and 23.3 mW)
is applied to the sample surface for 1min at
the tracks of 27500 μm, 28500 μm, 29500 μm,
30500 μm and 31500 μm respectively.
Figure 22 shows TGA results for Lube-1+ which
is the improved Lube-1 lubricant. A significant
improvement in thermal stability of lubricant
molecules has been achieved as high as
403 ºC. Our results showed that the evaporate
rate for Lube-1 is slower than that for
commercial lubricant such as AM3001.
To test the thermal stability of the lubricant
films under laser irradiation, we use HAMR
platform to focus the laser to lubricant film
Figure 21.
61
A light line in OSA image was observed when
the output power is larger than 25 mW for
Z-dol film and 30 mW for AM3001 film. Such
light line represents the lubricant depletion or
complete removal from media surface.
For the sample with Lube-1 film, the light
line was not observed under same condition.
We therefore fix the output power as 20 mW
which is estimated as 125 mW/μm2 of laser
intensity at the exposed site averagely without
consideration of Gaussian spatial distribution
and irradiate for different time span for 1min,
3min, 5min and 7min. The OSA results are
shown in Figure 23.
Figure 22.
LEFT
Figure 21. As-deposited
lubricant film uniformity
observed by OSA for
the Lube-1 (left) and
commercial lubricant
(right).
Figure 22. TGA result
for newly developed
lubricant (Lube1+).
Figure 23.
Figure 23. Lubricant film
morphology after laser
irradiation for AM3001
(left) and Lube-1 (right)
observed using OSA.
62
Compared to commercial lubricants, Lube-1
film has good initial uniformity and excellent
thermal stability under laser irradiation. This
novel lubricant film also presents better
lubricity and corrosion resistance for magnetic
head disks comparing to commercial
lubricants as shown in Figures 24 and 25.
In the HAMR technology, one of the key
challenges is to integrate the magnetic
head with optical head with tiny laser spot
output and high transmission efficiency. The
requirement for spot size of optical head
varies with desired recording density. Shown
in Figure 27 are the dependences of the
density on the track widths with bit aspect
ratio, the ratio of track pitch to bit length,
as parameter. If the aspect ratio is set to 4,
recording with the track width of 43 nm can
achieve density of 1 Tb/in2. This means that
the FWHM laser spot size should be around
RIGHT
Figure 24. Water contact
angles of lube 1 as well
as Zdol 2000, and A20H
were measured. The
lube1 show the highest
water contact angle
compared to Zdol and
A20H.
Figure 25. Corrosion
results for the media
lubricated with lube-1
and commercial
lubricant Z-dol and
A20H measured
by optical surface
analyzer (left) and TOFSIMS(right).
Figure 26. Frictional
properties of Lube1
compare to Z-dol and
A20H.
Figure 24.
Figure 26.
40 nm in the case of the track width decided
by the laser beam spot size. The higher the
recording density is required, the smaller the
laser spot size is needed.
With conventional focusing approach, an
ideally achievable smallest light spot due to
the diffraction limit will be determined by the
equation,
where d is the
diameter of a focal spot, λ is the working
wavelength and is the numerical aperture of
a focal lens. Within visible range, the smallest
ideal spot size can be achieved is around λ/2,
or several hundreds of nanometers with the
consideration of the fact that NA is normally
less than one. Even if a solid immersion lens
is used, its NA maybe up to 2~3, and the spot
size of at most 130nm can be obtained even
the working wavelength is set to 400 nm.
Apparently, it is still far from the desire of
applications, e.g., HAMR technology.
Figure 25.
The near field of nano-aperture on an opaque
plate is another possible solution to obtain
small light spot since it is the aperture size
rather than diffraction limitation which
determines the near filed spot size. However,
the efficiency is too low for any practical
applications. As theoretic prediction, the
efficiency (light intensity density) of an
opaque aperture with size of d is proportional
to (d/λ)4. So for an aperture with diameter of
λ/10, the efficiency can only reach the order
of 10-4. Due to low efficiency of near field
optics, some enhancement techniques have
to be adopted for any pragmatic applications.
Surface plasmon effect based on some noble
metals such Ag, Au, etc., comes into the sight
of scientists and engineers in this area since
after conversion from visible light, the surface
plasmon is believed to be able to concentrate
and channel through sub-wavelength
structures due to its higher momentum.
The resulting local field is also greatly
enhanced. These are exactly the most desired
features for many applications.
Figure 27.
63
On the other hand, a properly-designed
conventional optical waveguide can achieve
high transmission efficiency. Nevertheless,
it is almost impossible to obtain nanosize light spot. However, if the design of a
waveguide combines a structure to excite
surface plasmon, both high efficiency and
small spot size can be met. Figure 28(a)
shows the intensity distribution of one of
DSI’s HAMR optical head design along the
light propagation direction. The cross-section
intensity distribution of light field at 5 nm
away from the exit is shown in Figure 28 (b).
The peak intensity can reach around 50, and
the size of light spot is only around 20 by
28 nm2.
Figure 28. (a)
LEFT
Figure 27. Magnetic
recording density with
track width.
Figure 28. (a) Light
intensity distribution
along the propagation
direction. (b) Intensity
distribution on the
cross-section at 5 nm
away from exit.
Figure 28. (b)
64
spintronics, media and
interface division
1. Nanomagnetics and Media Technology
(a) Reduction of grain size & distribution
using synthetic nucleation layer
Reduction of grain size and grain size
distribution is a major task for media
researchers. For 400-500 Gb/in2 recording
media, grain pitch (center-to-center distance
between the grains) has to be about
5.7 nm with a distribution less than 15%.
Traditional methods for grain size reduction,
such as doping may not help in achieving a
narrow distribution. This is because, in the
conventional deposition techniques, the
nucleation sites are generated randomly
by the species of atoms that arrive at the
substrate first. Therefore, the resultant film will
have a larger distribution, as the nucleation
sites may not be controlled very well. On the
other hand, if a synthetic nucleation layer
can be designed to have well-controlled
nucleation sites with dense and almost precise
spacing, the grain size and distribution can be
RIGHT
Figure 1. TEM images
of intermediate layers
deposited (a) without
and (b) with synthetic
N-layers.
reduced. With this view in mind, experiments
were carried out by introducing a synthetic
nucleation (SN) layer in the recording media
design.
Figure 1 shows the TEM images of
intermediate layers deposited (a) without
and (b) with SN layers. Figure 2 also shows
the grain pitch distribution. It can be noticed
that the mean grain pitch is reduced from
about 7 nm to less than 6 nm, when SN layer
is used. It can also be noticed that the grain
pitch distribution is reduced when SN layers
were used. With most of the techniques used
for grain size reduction, controlling of C-axis
dispersion could be a challenge. However,
we observed that with the SN layer method,
no significant compromises were made in
the magnetic properties or in the C-axis
orientation. These results indicate that the
introduction of SN layer is an useful technique
to reduce the grain size.
Figure 1.
(a) No N-layer
(b) With N-layer
(b) Hybrid soft magnetic underlayers for
perpendicular recording media
for the recording layer. If the template layers
for the crystalline SUL are thin enough (in
our current designs, it is about 7 nm but
we target at 1-2 nm), then improvement in
writability will be observed. With ring heads,
improvements were observed even at 7
nm of template layers. Current results show
that optimized properties between C-axis
orientation and roughness could be obtained
when the ratio of amorphous to crystalline
SUL thickness is about 3. Figure 3 shows the
trend of average roughness (Ra), and C-axis
dispersion (Δθ50) as measured from the
rocking curves. In addition to improving the
recording performance, the Hy-SUL design
is also a potential way to overcome the
problem of increased cost and scarcity of Ru
intermediate layer target.
In order to improve the writability and reduce
the T50, it is essential to reduce the spacing
between the SUL and the writer pole. One of
the major factors to contribute to this spacing
is the intermediate layer thickness, which is
currently ranging from 15 to 20 nm. Reduction
of intermediate layer thickness has been a
key focus of our research in the past. We have
proposed media with magnetic intermediate
layers, media with fcc-FeCo intermediate
layers as ways to solve this problem. Recently,
we have been investigating hybrid soft
magnetic underlayers to solve the problem
of intermediate layer thickness. In hybrid soft
underlayer design, an amorphous layer is used
in the bottom and a crystalline SUL is grown
on top to provide epitaxial growth conditions
Figure 2.
65
Figure 3.
LEFT
Figure 2. Grain Size
distribution of IL
deposited with and
without synthetic
N-layers.
Grain Size Distribution in the Intermediate Layer
No N-Layer
N-layer (0.08 nm)
N-layer (0.18 nm)
70
Δθ50 of Co (degrees)
No. of Grains
80
N-layer (0.24 nm)
60
50
40
30
20
10
0
4
5
6
7
8
Grain Size(nm)
9
10
11
6
5.5
5
4.5
4
3.5
3
2.5
0.3
0.2
0.1
0
0
1
2
3
Thickness ration of a-SUL vs C-SUL
4
Roughness (nm)
90
Figure 3. Δθ50 and
average roughness of
media deposited on
hybrid SUL, as a function
of thickness ratio of
a-SUL and the crystalline
SUL.
66
spintronics, media and interface division
RIGHT
Figure 4. Out-of-plane
and in-plane hysteresis
loops of samples with
various MgO layer
thickness. (a) 1 nm; (b) 2
nm; (c) 4 nm.
(c) High anisotropy FePt perpendicular
media for 1 Tbits/in2
i. Reduction of the fabrication temperature
by new intermediate layer
The superparamagnetic limit of Co alloy
media will be reached at an areal density of
about 600-800 Gbits/in2. So it is desirable to
use some new materials with high anisotropy
constant for 1 Tbits/in2. Chemically ordered
FePt with L1o (CuAu-I) structure (face centered
tetragonal- fct) possess very high magnetic
anisotropy constant (7×107 erg/cm3) which
allows them to have very small magnetically
stable grains (2.6 nm) which can support the
areal density beyond 10 Tbits/in2. However,
the high temperature (above 500 ºC) required
for the formation of L1o phase and reduction
in the grain size are the main challenges
for the application of FePt for high density
magnetic recording media. The team in DSI
has been developing methods to fabricate
the L1o FePt (001) texture at low temperature
of below 350 ºC. During last year, we have
worked on methods to reduce the grain
size and maintain other properties such as
magnetic and crystallographic properties.
These efforts are described in the following
sections.
Although highly chemically ordered FePt films
with perpendicular anisotropy were obtained
by some methods below 400 °C, the coercivity
was less than 8 kOe. For 1 Tbits/in2, the
required lowest coercivity is12 kOe.
In these methods, the use of MgO single
crystal or random orientation of FePt films or
complex thin film deposition technology are
not suitable for industrial applications. We
demonstrate that FePt films with coercivity
higher than 12 kOe were be fabricated on
glass substrate with MgO(200) intermediate
layer and CrRu(200) underlayer at 350 ºC by
conventional magnetron sputtering.
The out-of-plane and in-plane hysteresis
loops of samples with different MgO thickness
measured by VSM are shown in Figure 4 (a)-(c).
The in-plane coercivity increased with MgO
layer thickness, due to the increase of L1o
FePt (200) phase in the film (XRD data). The
out-of-plane coercivity of FePt films increased
from 5.0 to 9.1 kOe when MgO increased from
Figure 4.
(a)
(b)
(c)
1 nm to 2 nm. Further increase of MgO layer
thickness caused the decrease of out-of-plane
coercivity (5.8 kOe). The Ku of FePt layer grown
on MgO (1,2 nm)/CrRu was 1.8-2.0×107 erg/cc,
estimated by Ku=Ms×Hk/2, where Ms and Hk
were saturated magnetization and anisotropy
field, respectively. When MgO thickness
increased to 4 nm, the Ku decreased to 1.2
×107 erg/cc. The higher Ku of FePt layer on
MgO (1, 2 nm)/CrRu than that of MgO
(4 nm)/CrRu was therefore caused by higher
chemical ordering of FePt layers due to
optimized lattice mismatch. Cross-sectional
TEM images of the samples with 1 and 4 nm
MgO layer are shown in Figure 5. For 4 nm
MgO layer thickness, the lattice spacing of
MgO layer along [001] axis was 0.211 nm,
which was consistent with bulk MgO. While for
the sample with 1 nm MgO layer, the lattice
spacing of MgO layer (d200=0.226 nm) along
[001] axis expanded by 7.1 % with respect to
bulk MgO (d200=0.211 nm).
Figure 5.
67
In order to reduce the effect of magnetization
reversal on the coercivity, 4 nm FePt layers
were deposited on the MgO/CrRu underlayer.
AFM and TEM investigation the 4 nm FePt is
isolated islands and thus S-W rotation will be
dominated. The out-of-plane hysteresis of the
samples are shown in Figure 6. The coercivity
of FePt film grown on MgO(1 nm)/CrRu was as
high as 12 kOe.
LEFT
Figure 5. Cross-section
TEM images of FePt/
MgO/CrRu/galss with
the MgO layer thickness
of (a) 1 nm; (b) 4 nm.
The insets are the iFFT
image of MgO layers.
Figure 6. Out-of-plane
hysteresis loops of 4 nm
FePt films with 1 nm and
4 nm MgO layers.
Figure 6.
68
ii. Reduction of grain size by carbon
element doping and new intermediate
layer
Normally, the grain size of magnetic recording
media is controlled by the sputtering
conditions and underlayers with small grain
size and element doping. These methods
have made a significant success in reduction
of grain size in currently used Co alloy
perpendicular media which are deposited at
room temperature. However, at the elevated
temperature the contribution of some of
these methods become lower. Here the team
in DSI proposed a method of the reduction
of grain size in which a intermediate layer
with low surface energy and high interface
interaction was combined with element
doping. The surface energy of MgO was
RIGHT
Figure 7. Plan-view
and cross-section TEM
images of FePt-C films.
Figure 7.
(a)
(b)
1.1 J/m2 and FePt was ~2.9 J/m2 it is therefore
expected that island growth (Vomer-Weber
growth) occurred. By further combining
element doping, the diffusion of Fe/Pt atoms
will be restricted and thus small columnar
FePt grains will be formed. FePt:C films with
the structure of glass/ Cr90Ru10 (30 nm)/MgO
(2 nm)/FePt:C (~12 nm) were prepared by
co-sputtering an Fe50Pt50 alloy target and a C
target. Figure 7(a) and (b) show the plan-view
and cross-section TEM images of the FePt:C
films with 15vol.% C, respectively. From the
TEM images, It is obvious the FePt grains are
columnar and grain size is around 8-10 nm.
Corresponding magnetic property does not
show any deterioration and coercivity is larger
than 12 kOe with maximum measuring field
20 kOe.
2. Spintronics and Devices
(a) Theoretical studies of intrinsic spin Hall
effects based on the quantum and
gauge field theory
and the SU(2) spin gauge to realize a spin Hall
modulation which distinguishes the intrinsic
from the exterinsic effect. This device also has
other advantages in terms of stability. Below
is the schematic illustration of the forces in
opposite transverse directions with proper
setting of the applied Bz fields. Spin Hall
can be modulated/ reversed by tuning and
reversing the Ez field.
The detection of spin Hall remains elusive as
the intrinsic effect is weak and its detection
could be confused with the extrinsic effect.
We proposed a device which utilizes electron
trajectory induced by both the topological
Landau / Coulomb gauge
Topological gauge
SU (2) spin gauge
69
LEFT
This cartoon summarizes
the various Hall effects
from the perspective
of gauge theory. Spin
Hall is presently keenly
studied by spintronic
research groups in the
US and Japan.
Spin Hall can potentially
be used for devices eg.
memory and magnetic
sensor.
Courtesy of Inoue et al. Science Magazine 23 Sept. 2005
Z (lab)
BU(1)z Bz(applied)
Bz(applied)
Spin- dependent force due
to the SU(2)spin angle
x (lab)
-y (lab)
Ez
BSU(2)z
2DEG
Spin dependent force due to the
topological gauge or Berry
phase solid angle
R
Magnetic nonopole
LEFT
Numerical evaluation
of the two forces in
opposite directions, for
three values of the field
angle (deg).
At a critical E field value,
the two forces cancel
one another completely,
switching off the spinHall effect.
Spin Hall cancellation
70
(b) Magnetic head technology towards
1Tb/in2 and beyond
i. A read sensor working in the toggle
mode is proposed.
As shown in Figure 1, the free layer comprises
a balanced synthetic—antiferromagnetic
(SAF) multilayer. The magnetization of the free
SAF layer is perpendicular to the air-bearing
surface (ABS) when bias field is applied in
the direction of the ABS. The magnetization
of the reference layer is fixed to be parallel
to the ABS instead of perpendicular as is the
conventional case. As shown in Figure 2, the
sensitivity of the toggle read sensor (for small
track width) improves significantly compared
to the conventional abutted junction bias
type. For a toggle sensor with long height
structure, performance in both the sensitivity
and linearity has also been improved because
increased sensor height can be used for the
lower bias field. The lower bias field is also
compatible with the small gap structure of an
in-stack bias scheme. Simulation results also
show that the thermal magnetic noise in the
RIGHT
Figure 1. The read
structure : conventional
in-stack biased reader
(a) and toggle mode
reader (b).
Figure 1.
Figure 2. Transfer curves.
Circles: conventional
bias, Square: toggle
mode.
Figure 3. The amplitude
and frequency of the
two FMR peaks. Square:
FMR of free layer.
Circles: FMR of RL/PL.
Figure 3.
(a)
(b)
toggle sensor is much smaller than that in
the conventional biased sensor. Experimental
results for both the current-in-plane (CIP) and
tunneling-magneto-resistive (TMR) sensors
with toggle mode are consistent with our
calculation results.
ii. High-frequency noise in TMR heads
A systematical study on the mag-noise of TMR
heads has been performed. For some small
sensors, an “abnormal” FMR peak is observed.
This additional FMR peak appears only at the
anitparallel magnetization configuration of
the free layer and the reference layer and its
amplitude increases monotonically with
increase of magnetic field, which is much
higher than that of the free layer. After
examining the spin transfer effect and hard
bias influence, it found that this abnormal FMR
is from the magnetization fluctuations of the
composite reference/pinned (RL/PL)layers,
showing the importance in the control of
RL/PL magnetic stability for small sensors.
Figure 2.
(c) Spin transfer (ST) MRAM
The smaller cell size, the smaller switching
current is required. As the cell size scale down,
the current induced field effect is very small.
Figure 1 shows SEM image of a cell with
size of about 100 nmx200 nm. Higher spin
polarization, higher spin transfer efficiency
is. Higher MR of the MTJ is preferred for ST
MRAM. We developed high MR ratio MTJ with
MgO barrier. Figure 2 shows the R-H curve
of the cell. Figure 3 shows a current driven
switching of another ST MTJ MRAM. The
switching current density is only 6 mA/μm2. If
a cell process of 90 nm is adapted, the writing
current required is less than 50 μA. Ultra-low
power dissipation can be achieved using the
ST MRAM structure. The low power dissipation
ST MRAM is promising in the application of the
passive radio frequency identification (RFID)
tag and the other portable consumer devices.
As the cell size scales down, the switching field
increases in order to maintain the thermal
stability. Large switching current in the field
switching MRAM may cause large electromigration in the word line and bit line in
high density MRAM. Slonczewski and Berger
pointed out that an electronic current that
flows perpendicularly through a magnetic
multilayer could exert a torque on the
magnetic moments of the hetero-structure.
The transfer of spin angular momentum
from a spin-polarized current to a nanometer
scale ferromagnet can reversibly switch the
orientation of the FM’s moment in a CPP
cell. The switching current density is only
dependent on the magnetic properties of the
cell. It is independent on the cell size. Thus, the
ST MRAM can be scaled down.
Figure 1.
71
LEFT
Figure 1. SEM image of
the ST MRAM cell.
Figure 2. MR-H curve of
the MgO MTJ.
Figure 3. Current driven
switching of a ST.
Figure 2.
Figure 3.
72
n It provides static and dynamic analysis of air
3. Head-Disk Systems
(a) Modeling & simulation tool
development for head disk interface
bearing sliders. (Figure 2).
DSI has been actively involved in developing
the simulation platform for simulation of head
disk interface and ABS design in the past years.
ABSolution 2.0 is DSI developed air bearing
simulator for ABS design & simulations. Its
main features include:
n It is based on Finite Element Method (FEM)
and high efficiency algorithm. It has excellent
convergence property, high accuracy and fast
speed in simulations.
n The simulation platform consists of air
bearing model, contact/friction model, short
range force models, and slider and suspension
models, etc.
n It has a very user-friendly Graphic User
Interface (GUI) with powerful pre- and proprocessors for ABS design and simulation &
results plotting (Figure 1).
RIGHT
Figure 1. GUI of
ABSolution 2.0.
n It can work well with Ansys software so
that it can be used for more comprehensive
simulations such as dynamics of the whole
HDI system, thermal FH control slider and PZT
active slider, etc.
(b) Dynamics of air bearing-slider suspension system
Based on the simulation platform developed
by DSI, the dynamic motion of read/write
head in both flying-height (FH) and off-track
directions, even on-track direction, can
be obtained (See Figure 3). It is helpful to
characterize dynamics of head positioning in
3D directions and understand the interactions
among the air bearing, slider, disk and
suspension (Figure 4). In addition, conduct
induced and waviness induced off-track
vibrations of slider-suspension system are also
investigated.
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 2. Dynamic
results of simulation.
Figure 3. Dynamics of
head positioning.
Figure 4. Various
dynamic results of
air bearing-slidersuspension system.
(c) Thermal flying height control (TFC)
slider
minimize the FHM caused by the disk
waviness. A series of work has been done on
investigating the effects of air bearings on the
thermal actuation efficiency and the capability
in following disk waviness of the TFC sliders,
and explores their inherent relations as shown
in Figure 6. ABS design strategies and new TFC
slider structure and ABS designs have been
proposed for improving thermal actuation
efficiency and enhance the capability in
following disk waviness.
A simulation platform is developed for the TFC
sliders in DSI which consists of the FE model
of TFC slider, the air bearing model and the
heat transfer model. A coupled-field analysis
scheme is used to solve the interactions
among the aerodynamic, thermal and
structural fields, as shown in Figure 5.
One important criterion for TFC slider design
is its thermal actuation efficiency. The high
actuation efficiency, i.e., large FH reduction
with small applied power, is desirable so that
the TFC slider has a large enough stroke
for FH adjustment. Another crucial criterion is
that the TFC slider must have enough
capability in following disk waviness so as to
73
(d) The physics behind lubricant transfer
from disk to slider
Slider-disk spacing has been reduced to less
than 10 nm to increase recording density.
The behavior of a molecular thin lubricant on
disk surface in such a narrow spacing plays
Figure 5.
LEFT
Figure 5. Simulation of
TFC slider.
Figure 6. Thermal
actuation efficiency of
TFC sliders.
FH (nm)
Ptotrusion (nm)
Figure 6.
74
a key role in building a stable slider-disk
interface and has been studied extensively.
However, the process of lubricant transfer
from disk to slider through evaporation and
condensation is still less studied. The lubricant
transfer can cause the problems of flying
stiction and lubricant depletion on the disk
surface. The thickness of lubricant transferred
to the slider surface is also important for a
further reduction in slider-disk spacing.
The physics behind the process of lubricant
transfer and lubricant accumulation on slider
is explained in a paper recently published at
Applied Physics Letters [90(2007) 143516]. The
parameters, such as lubricant bonding ratios
on slider and disk, area density of lubricant
adsorption sites on slider surface, etc. are
involved in the explanation. The effect of slider
air bearing pressure on the lubricant transfer
is also discussed. Then, effects of several
important parameters, such as lubricant
molecular weight, lubricant thickness and
bonding ratio on disk surface on the lubricant
It is found that the lubricant transfer is
not affected by slider air bearing pressure.
Lubricant molecular weight plays a dominant
role in the lubricant transfer and accumulation
(Figure 7). For a low molecular weight
lubricant, the slider pad is in a “flooded”
condition. Lubricant thickness on the pad is
comparable with that on the disk. The rate
of lubricant flowing away from the pad is
also very high. With the increase in lubricant
molecular weight, the slider pad quickly
changes to a “starved” regime. Lubricant
thickness on the pad becomes negligible and
the lubricant flow rate also decreases sharply.
The lubricant transfer and accumulation
also strongly depend on lubricant thickness
and bonding ratio on disk surface. A thinner
lubricant and higher bonding ratio of lubricant
on disk surface reduce the lubricant transfer
and accumulation obviously.
Figure 7.
(a)
(b)
9
6
Inner leading edge pad
8
Lubricant Flow Rate, micron^3/s
Lubricant Thickness, Angstrom
RIGHT
Figure 7. (a) Thickness
of lubricant transferred
from disk on each of the
three pads of the slider
and (b) the amount
of lubricant removed
from each of the three
pads in one second as
a function of lubricant
molecular weight.
Lubricant thickness on
disk surface is 1.2 nm
and temperature at
35 ºC. Inner leading
edge pad means the
leading edge pad at
inner radius.
transfer and accumulation are studied based
on a commercial slider.
Outer leading edge pad
7
Trailing edge pad
6
5
4
3
2
1
Inner leading edge pad
5
Outer leading edge pad
Trailing edge pad
4
3
2
1
0
0
1.5
1.8
2.1
2.4
Lubricant Molecular Weight, kDolton
2.7
3
1.5
1.8
2.1
2.4
Lubricant Molecular Weight, kDolton
2.7
3
75
INTELLECTUAL CAPITAL
publications
patents
PUBLICATIONS
76
intellectual capital
publications
Publications constitute
a major integral part of
DSI’s intellectual capital.
We continued to produce
outstanding papers of
research published at key
international conferences
and prestigious journals.
A total of 20 papers were
invited at international
conferences of which one
was a keynote address.
Integrative Science And
Engineering Division
1. Zhang Jun, Ji Rong, J.W. Xu, B.X. Xu, S.B. Hu, H.X. Yuan,
S.N. Piramanayagam, “Lubrication for heat assisted magnetic
recording media”, Intermag 2006, USA.
2. Tan Seng Ghee, M B A Jalil, Bala Kumar AL Sundaram
Pillay, K L Teo, Thomas Liew Yun Fook, “Utilization of
magnetoelectric potential in ballistic nanodevices”, Journal of
applied physics, Vol. 99, No. 8, pp 084305-1 to 084305-6, 2006.
3. Ji Rong, Thomas Liew Yun Fook and Chong Tow Chong,
“Effect of acrylic acid vapor on the head disk interface”, Journal
of applied physics, Vol. 99, No. 8, pp 08N110-1 to 08N110-3,
2006.
4. Ji Rong, Thomas Liew Yun Fook and Chong Tow Chong,
“Effect of acrylic acid vapor on lubricated recording hard-disk
media surfaces”, Applied surface science, Vol. 252, No. 19,
pp6683-6685, 2006.
5. Zhang Jun, S M Hsu, Thomas Liew Yun Fook,
“Nanolubrication: patterned lubricating films using ultraviolet
(UV) irradiation on hard disks”, Journal of nanotechnology, Vol.
7, No. 2, pp. 286-292, 2006.
6. M.B.A Jalil, Tan Seng Ghee, A.O. Adeveve, “Magnetic
properties of patterned ferromagnetic nanowires”, Journal of
computational and theoretical nanoscience, Vol. 4, No. 2, pp
270-274, 2006.
PUBLICATIONS
Mechatronics And Recording Channel Division
1.
Zhang Qide, Guo Guoxiao, Bi Chao, “Air bearing spindle motor for hard disk drives”,
Tribology & lubrication technology, pp36-42, 2006
2.
Huang Jichang, Bi Chao, Jiang Quan, Tan Choon Keng, Lim Choon Pio,
“Performance analysis of the vision measuring machine for spindle motor”, 2006 IEEE
Instrumentation and Measurement Technology Conference (IMTC2006), pp568-572,
2006
3.
Branislav Hredzak, G X Guo, “Adjustable balancer with electromagnetic release of
balancing members”, IEEE transactions on magnetics, Vol 42 # 5, pp1591-1596, 2006
4.
Tan Kok Heng, Wong Wai Ee, Ye Weichun, Zou Xiaoxin, Du Chunling, “Rapid
Microtrack modelling with vibrations for servo perpendicular recording in hard disk
drives”, IEEE International Magnetics Conference (INTERMAG 2006), pp603, 2006
5.
Du Chunling, Guo Guoxiao, Zhang Jingliang, “Quantizer model and performance
analysis for hard disk drives”, IEEE International Magnetics Conference (INTERMAG
2006), pp602, 2006
6.
Yip Teck Hong, Tan Choon Keng, Kuan Yoke Kong, “The behavior of spiral flow
structures along the trailing edges of E-block arms under increasing airflow velocities”,
IEEE International Magnetics Conference (INTERMAG 2006), pp607, 2006
7.
MR Elidrissi, George Mathew, “Weakly-Constrained Coding with parity-check
for perpendicular recording channels”, IEEE International Magnetics Conference
(INTERMAG 2006), pp787, 2006
8.
X C Shan, Zhang Qide, Sun Yaofeng, Wang Zhenfeng, “Design, fabrication and
characterization of an air-driven micro turbine device”, International MEMS Conference
2006 (iMEMS2006), 2006
9.
X C Shan, Zhang Qide, Sun Yaofeng, Wang Zhenfeng, “Design, fabrication and
characterization of an air-driven micro turbine device”, Journal of physics: conference
series 34, Vol. 34, pp316-321, 2006
10. Zhang Qide, X C Shan, “Numerical and experimental investigations of micro air
bearings for micro systems”, International MEMS Conference 2006 (iMEMS2006), 2006
11. Zhang Qide, X C Shan, “Numerical and experimental investigations of micro air
bearings for micro systems”, Journal of physics : conference series 34, Vol. 34, pp310315, 2006
12. Qin Zhiliang, “Decision-feedback turbo equalization for coded intersymbol
interference channels”, 1st IEEE Conference on Industrial Electronics and Applications
(ICIEA 2006), pp1483-1487, 2006
13. Du Chunling, Xie Lihua, Guo Guoxiao, Teoh Jul Nee, Li Qing, Branislav Hredzak,
Zhang Jingliang, “A generalized KYP Lemma based control design and application for
425 kTPI servo track writing”, American Control Conference 2006, pp1303-1308, 2006
77
PUBLICATIONS
78
14. Zheng Jinchuan, Du Chunling, Guo Guoxiao, Wang Youyi, Zhang Jingliang, Li
Qing, Branislav Hredzak, “Phase lead peak filter method to high TPI servo track writer
with microactuators”, American Control Conference 2006, pp1309-1314, 2006
15. Guido Hermann, Branislav Hredzak, Matthew C Turner, Ian Postlethwaite, Guo
Guoxiao, “Improvement of a novel dual-stage large-span track-seeking and trackfollowing method using anti-windup compensation”, American Control Conference
2006, pp1190-1997, 2006
16. Thum Chin Kwan, Guo Guoxiao, Ben M Chen, Tan Kim Piew, “Fast settling peak
filter for narrow-band NRRO rejection”, 2006 ASME/JSME Joint conference on
Micromechatronics for Information and Precision Equipment, pp3 pages, 2006
17. Yang Jiaping, Mou Jianqiang, Chong Nyok Boon, Lu Yi, Zhu Hong, Jiang Quang,
Kim Whye Ghee, Chen Jian, Guo Guoxiao, Ong Eng Hong, “Probe recording
technology using novel MEMS devices”, 2006 ASME/JSME Joint Conference on
Micromechatronics for Information and Precision Equipment, pp3 pages, 2006
18. Zhang Qide, Shan Xue Chuan, “Dynamic Characteristics of Micro Air Bearings
for Micro Systems”, 3rd Asia-Pacific Conference of Transducers and Micro-Nano
Technology (APCOT 2006), pp1-4, 2006
19. Long Haohui, T Liu, H L Li, Liu Zhejie, E P Li, Wu Yihong, A O Adeyeye,
“Micromagnetic simulations of magnetic nanowires with constrictions by FIB”, Journal
of magnetism and magnetic materials, Vol. 303 # 2, ppe299-e303, 2006
20. Lin Song, Bi Chao, Jiang Quan, Hla Nu Phyu, “Analysis of three synchoronous drive
modes for the starting performance of spindle motor”, Asia-Pacific Magnetic Recording
Conference (APMRC ‘06), ppBB-04-01 to BB-04-02, 2006
21. Kannan Sundaravadivelu, Zhang Qide, “Numerical simulation of turbulent air flow in
hard disk drives”, Asia-Pacific Magnetic Recording Conference (APMRC ‘06), ppBQ-0101 to BQ-01-02, 2006
22. Hla Nu Phyu, Bi Chao, Lin Song, “Numerical modeling and performance analysis of
a disk drive spindle motor using circuit-field coupled systems”, Asia-Pacific Magnetic
Recording Conference (APMRC ‘06), ppBP-01-01, 2006
23. Tan Kim Piew, Kannan Sundaravadivelu, Zhang Qide, Ong Eng Hong, Ong Eng
Teo, Thum Chin Kwan, “Flow structural interaction of the actuator arm in hard disk
drive”, Asia-Pacific Magnetic Recording Conference (APMRC ‘06), ppBQ-03-01 to BQ-0302, 2006
24. Soh Cheng Su, Bi Chao, Chua Kian Chong, “Direct PID tuning for spindle motor
systems”, Asia-Pacific Magnetic Recording Conference (APMRC ‘06), ppBP-06-01 to B06-02, 2006
25. Tan Chok Shiong, Albert, Maria Anastasia Suriadi, Zhang Qide, “Studies on air
flow induced vibration in a simplified hard disk drive using LES”, Asia-Pacific Magnetic
Recording Conference (APMRC ‘06), ppBQ-07-01 to BQ-07-02, 2006
Invited
PUBLICATIONS
26. Huang Jichang, Bi Chao, “A method for high precision spindle motor eccentricity
measurement”, Asia-Pacific Magnetic Recording Conference (APMRC ‘06), ppBP-03-01
to BP-03-03, 2006
27. Zhang Qide, Xu Baoxi, Maria Anastasia Suriadi, Ong Eng Hong, Yip Teck Hong,
“Temperature distribution of magnetic head in HAMR system”, Asia-Pacific Magnetic
Recording Conference (APMRC ‘06), ppBQ-05-01 to BQ-05-02, 2006
28. Bi Chao, Nay Lin Htun Aung, Hla Nu Phyu, Jiang Quan, Lin Song, “Influence of
drive current to unbalanced-magnetic-pull in spindle motor”, Asia-Pacific Magnetic
Recording Conference (APMRC ‘06), ppBP-08-01 to BP-08-02, 2006
29. Du Chunling, Zhang Jingliang, Ong Eng Hong, “Timing jitter modeling and
minimization for a servo track writer”, Asia-Pacific Magnetic Recording Conference
(APMRC ‘06), ppDB-03-01 to DB-03-02, 2006
30. Jiang Quan, Bi Chao, Lin Song, “Drag torque measurement of hard disk drive spindle
motors”, Asia-Pacific Magnetic Recording Conference (APMRC ‘06), ppBP-05-01 to BP05-02, 2006
31. Chai Kao Siang, Liu Zhejie, Li Jiangtao, Long Haohui, “3D analysis of medium
field with consideration of perpendicular head-medium combinations”, Asia-Pacific
Magnetic Recording Conference (APMRC ‘06), ppDQ-07-01, 2006
32. Zhang Songhua, Wong Wai Ee, “Evaluation of servo patterns for perpendicular
recording”, Asia-Pacific Magnetic Recording Conference (APMRC ‘06), ppBQ-13-01 to
BQ-13-02, 2006
33. Z M He, H T Loh, M Xie, “A two-dimensional probability model for evaluating reliability
of piezoelectric micro-actuators”, International journal of fatigue, Vol. 29 # 2, pp245253, 2007
34. Z J Liu, J T Li, H H Long, E T Ong, E P Li, “Dynamic simulation of high-density
perpendicular recording head and media combination”, IEEE transactions on
magnetics, Vol. 42 # 4, pp 943-946, 2006
35. Jiang Quan, Bi Chao, Lin Song, “An effective method to measure back EMFs and their
harmonics of permanent magnet AC motors”, Journal of applied physics, Vol 99, # 8,
pp08S309-1 to 08S309-3, 2006
36. Liu Zhejie, Long Haohui, E T Ong, E P Li, “A fast fourier transform on multipole
algorithm for micro magnetic modeling of perpendicular recording media”, Journal of
applied physics, Vol 99, # 8, pp08B903-1 to 08B903-3, 2006
37. X C Shan, Zhang Qide, Sun Yaofeng, R Maeda, “A micro turbine device with
enhanced micro air bearings”, 2006
38. C L Du, G X Guo, J L Zhang, L H Xie, “Interaction rejection of multiple microactuators
in dual-stage servos for hard disk drives”, IEEE transactions on control systems
technology, Vol. 14 # 3, pp493-500, 2006
79
80
PUBLICATIONS
39. Q D Zhang, X C Shan, G X Guo, Wong, Stephen, “Performance analysis of air bearing
in a micro system”, Material science and engineering A, Vol. 423 # 1-2, pp225-229, 2006
40. Li Qing, Zhang Jingliang, Branislav Hredzak, Guo Guoxiao, “Use of command input
shaping method to compensate clock/seed timing track closure in phase lock loop”,
1st IEEE Conference on Industrial Electronics and Applications (ICIEA 2006), pp85-89,
2006
41. Branislav Hredzak, Guido Herrmann, Guo Guoxiao, “A proximate-time-optimalcontrol design and its application to a hard disk drive dual-stage actuator system”, IEEE
transactions on magnetics, Vol. 42 # 6, pp1708-1715, 2006
42. Pang Chee Khiang, Guo Guoxiao, Ben M Chen, T H Lee, “Self-sensing actuation
for nanopositioning and active mode damping in dual-stage HDDs”, IEEE/ASME
transactions on mechatronics, Vvol. 11 # 3, pp328-338, 2006
43. Mou Jianqiang, Yang Jiaping, H.W. Ee, “Design evaluation of electrostatic actuated
AFM cantilever for probe data storage”, 3rd Asia-Pacific Conference of Transducers and
Micro-Nano Technology (APCOT 2006), pp1-4, 2006
44. Liu Xiangjun, Yang Jiaping, Y W Wang, C K Soh, “Study of heated AFM tip surface
using molecular dynamics simulation for thermomechanical data storage”, Asia-Pacific
Conference of Transducers and Micro-Nano Technology (APCOT 2006), pp1-4, 2006
45. Cai Kui, K A S Immink, “On the number of encoder states of a type of RLL codes”, IEEE
transactions on information theory, Vol. 52 # 7, pp3313-3319, 2006
46. Maria Anastasia Suriadi, Tan Chok Shiong, Albert, Zhang Qide, Yip Teck Hong,
Sundaravadivelu Kannan, “Numerical investigation of airflow inside a 1-inch hard
disk drive”, Journal of magnetism and magnetic materials, Vol. 303 #2, pp124-127, 2006
47. Long Haohui, T Liu, H L Li, Liu Zhejie, E P Li, Wu Yihong, A O Adeyeye,
“Micromagnetic simulations of magnetic nanowires with constrictions by FIB”, Journal
of magnetism and magnetic materials, Vol. 303 # 2, ppe299-e303, 2006
48. He Zhimin, Guo Guoxiao, L Feng, Wong Wai Ee, H T Loh, “Microactuation
mechanism with piezoelectric element for magnetic recording head positioning for
spin stand”,Proceedings of Institute of Mechanical Engineering. Part C, Journal of
mechanical engineering science, Vol. 220 # 9, pp1455-1461, 2006
49. Yip Teck Hong, Tan Choon Keng, Kuan Yoke Kong, “Behavior of spiral flow structures
along the trailing edges of E-block arms under increasing airflow velocities”, IEEE
Transactions on Magnetics, Vol. 42 # 10, pp2591-2593, 2006
50. Zheng Jinchuan, Guo Guoxiao, Wang Youyi, Wong Wai Ee, “Optimal narrow-band
disturbance filter for PZT-actuated head positioning control on a spinstand”, IEEE
transactions on magnetics, Vol. 42 # 11, pp3745-3751, 2006
PUBLICATIONS
51. Bi Chao, Nay Lin Htun Aung, Jiang Quan, Lin Song, “Influence of rotor eccentricity
to unbalanced-magnetic-pull in PM synchronous motor”, International Conference on
Electrical Machines and Systems (ICEMS 2006), 6 pages, 2006
52. Chua Kian Ti, Arief Yudhanto, Ong Eng Hong, Mou Jianqiang, “Investigation of
soft failure of small form factor HDD under forced vibration”, Asia-Pacific Magnetic
Recording Conference (APMRC ‘06), ppDQ-14-01 to DQ-14-02, 2006
53. Du Chunling, Xie Lihua, Teoh Jul Nee, Zhang Jingliang, Guo Guoxiao, “Twodimensional control of self-servo track writing for hard disk drives”, 9th International
Conference on Control, Automation, Robotics and Vision (ICARCV 2006), pp1247-1252,
2006
54. Yang Jiaping, “MEMS-based probe recording technology”, Journal of nanoscience and
nanotechnology, Vol. 7 # 2, pp181-292, 2006
55. Du Chunling, Xie Lihua, Teoh Jul Nee, Zhang Jingliang, Guo Guoxiao, “Twodimensional control of self-servo track writing for hard disk drives”, 9th International
Conference on Control, Automation, Robotics and Vision (ICARCV 2006), pp1247-1252,
2006
56. Branislav Hredzak, Guido Herrmann, Du Chunling, “Enhancement of short-span
seeking in a dual-stage seek-track following control using variable saturation”, 9th
International Conference on Control, Automation, Robotics and Vision (ICARCV 2006),
pp234-239, 2006
57. Liu Zhejie, Li Jiangtao, Chai Kao Siang, “An analytical solution of read sensor
response for perpendicular recording”, 10th Joint MMM/Intermag Conference (MMM
2007), pp427, 2007
58. Qin Zhiliang, Cai Kui, Zou Xiaoxin, “A reduced-complexity iterative receiver based on
simulated annealing for coded partial-response channels”, 10th Joint MMM/Intermag
Conference (MMM), pp52, 2007
59. Li Jiangtao, Liu Zhejie, Nay Lin Htun Aung, “Effect of radial magnetic forces in
permanent magnet motors with rotor eccentricity”, 10th Joint MMM/Intermag
Conference (MMM 2007), pp420, 2007
Network Storage Technology Division
1.
Invited
Renuga Kanagavelu, Yong Khai Leong, “ A bit-window based algorithm for balanced
and efficient object placement and lookup in large-scale object based storage cluster
” 15-May-06, 14th NASA Goddard/ 23rd IEEE Conference on Mass Storage Systems and
Technologies (MSST 2006).
81
PUBLICATIONS
82
2.
For Wei Khing, Xi Weiya, “Adaptive extents-based file system for object-based storage
devices” 15-May-06, 14th NASA Goddard/ 23rd IEEE Conference on Mass Storage
Systems and Technologies (MSST 2006).
3.
Wei Qingsong, Lin Wujuan, Yong Khai Leong, “Adaptive Replica Management for
Large-scale Object-based Storage Devices”, 15-May-06, 14th NASA Goddard/ 23rd IEEE
Conference on Mass Storage Systems and Technologies (MSST 2006).
4.
Xi Weiya, For Wei Khing, Wang Donghong, Goh Wai Kit, Renuga Kanagavelu,
“OSDSim - a simulation and design platform of an object-based storage device” 15May-06, 14th NASA Goddard/ 23rd IEEE Conference on Mass Storage Systems and
Technologies (MSST 2006).
5.
Wang Yonghong, Yeo Heng Ngi, Zhu Yao Long, Chong Tow Chong, T Y Chai, L Y
Zhou, Jit Bitwas, “Design and development of ethernet-based storage area network
protocol” 31-May-06, Computer communications .
6.
Lin Wujuan, Law Sie Yong, Yong Khai Leong, “A novel interval caching strategy
for video-on-demand systems” 13-Sep-06, 14th IEEE International Conference on
Networks (ICON2006).
7.
Lin Wujuan, Law Sie Yong, Yong Khai Leong, “A client-assisted interval caching
strategy for video-on-demand systems” 28-Nov-06, Computer communications.
Optical Materials And Systems Division
1.
L. P. Shi and T. C. Chong, “Nano phase change for data storage application”, Journal of
Nanoscience and Nanotechnology, Vol. 7, No. 1, 65 (2007).
2.
Y. Lin, M. H. Hong, C. S. Lim, G. X. Chen, L. S. Tan, Z. B. Wang, L. P. Shi, and T. C.
Chong, “Ultrafast laser induced parallel phase change nanolithography”, Applied
Physics Letters, Vol. 89, 041108, (2006).
3.
Selin H. G. Teo, A. Q. liu, J. B. Zhang and M. H. Hong, “Induced free carriers
modulation of photonic crustal intersection via localized optical absorption effect”,
Applied Physics Letters, Vol. 89, 091910, (2006).
4.
C. S. Lim, M. H. Hong, Y. Lin, Q. Xie, B. S. Luk’yanchuk, A. Senthil, and M. Rahman,
“Microlens array fabrication by laser interference lithography for super-resolution
surface nanopattering”, Applied Physics Letters, Vol. 89, 191125, (2006).
5.
Y. Z. Peng, T. Liew, T. C. Chong, C. W. An, and W. D. Song, “Anomalous Hall effect
and origin of magnetism in Zn1-xCoxO thin films at low Co content”, Applied Physics
Letters, 88, 192110 (2006).
PUBLICATIONS
6.
W. D. Song, L. P. Shi, X. S. Miao and T. C. Chong, “Laser synthesis of Sn-Ge-Sb-Te
phase change materials”, Mat. Res. Soc. Symp. Proc. Vol. 918, H08-03 (2006).
7.
X. S. Miao, L. P. Shi, H. K. Lee, J. M. Li, R. Zhao, P. K.Tan, K. G. Lim, H. X. Yang and T.
C. Chong, “Temperature dependence of phase-change random access memory cell”,
Japanese Journal of Applied Physics, Vol. 45, No. 5A, 3955-3958, (2006).
8.
B. X. Xu, S. B. Hu, H. X. Yuan, J. Zhang, Y. J. Chen, R. Ji, X. S. Miao, J. S. Chen and
T. C. Chong, “ Thermal effects of heated magnetic disks on the slider in heat assisted
magnetic recording”, Journal of Applied Physics, Vol. 99, No. 8, 08N102, (2006).
9.
B. X. Xu, H. X. Yuan, S. B. Hu, R. Ji, Y. J. Chen, J. Zhang, X. S. Miao, J. S. Chen and T.C.
Chong ,” Thermal effect on recording mark quality in heat assisted recording”, Journal
of Magnetism and Magnetic Materials, Vol. 303, e34-38, (2006).
10. H. F. Wang, L. P. Shi, G. Q. Yuan, X. S. Miao, W. L. Tan and T. C. Chong,
“Subwavelength and super-resolution nondiffraction beam,” Applied Physics Letters,
89, 17 1102, (2006).
11. H. X. Yuan, B. X. Xu and T. C. Chong, “Propagation properties of surface plasmon
along metal nano-aperture and nano-wire”, ODS2006 Proceedings of SPIE, Vol. 6282,
62821R-1 (2006).
12. L. P. Shi, T. C. Chong, X. Hu, J. M. Li, X. S. Miao, H. X. Yang and K. G. Lim, “Blue-ray
type super resolution near field optical disk with Sb2Te3 mask layers and a Tthermal
shield layer in front of the mask layer”, ODS2006 Proceedings of SPIE, Vol. 6282, 62821U
(2006).
13. B. S. Luk`yanchuk, W. D. Song, Z. B. Wang, Y. Zhou, M. H. Hong, T. C. Chong, J. Graf,
M. Mosbacher, and P. Leiderer, “New methods for laser cleaning of nanoparticles”
Chapter 3 in “Laser Ablation and its Applications”, Ed. by C. Phipps (Springer-Verlag,
Berlin, Heidelberg 2006, Springer Series in Optical Sciences, Vol. 129), pp. 37-67, (2006).
14. W. D. Song , L. P. Shi, X. S. Miao and T. C. Chong, “Phase change behaviors of Sndoped Ge-Sb-Te material”, Applied Physics Letters, Vol. 90, p091904-1 to 091904-3,
2007.
15. P. B. Phua, W. J. Lai, K. S. Tiaw, B. C. Lim, H. H. Teo, Y. L. Lim, M. H. Hong “Mimicking
optical activity for generating radially polarized light”, Optics Letters, Vol. 32, 376-378
(2007).
16. B. S. Luk`yanchuk , M. I. Tribelsky, V. Ternovsky, “Light scattering at nanoparticles
close to plasmon resonance frequencies”, Journal of Optical Technology, vol. 73, No 6,
pp. 371-377 (2006).
17. B. S. Luk`yanchuk, V. Ternovsky, “Light scattering by thin wire with surface plasmon
resonance: bifurcations of the Poynting vector field”, Physical Review. B, vol. 73, 235432
(2006) (DSI Best Paper Award).
83
PUBLICATIONS
84
18. M. I. Tribelsky, B. S. Luk’yanchuk, “Anomalous light scattering by small particles”,
Physical Review Letters, vol. 97, LP10283 (2006).
19. J. M. Li, L. P. Shi, H. X. Yang, K. G. Lim, X. S. Miao, H. K. Lee and T. C. Chong “
Integrated analysis and design of phase change random access memory (PCRAM) cell”,
7th Annual Non-Volatile Memory Technology Symposium, San Mateo, California, US,
November 5-8, (2006).
20. B. X. Xu, H. X. Yuan, X. S. Miao, J. Zhang, R. Ji and T. C. Chong, “ Thermal distribution
along cross track direction in heat assisted magnetic recording”, IEEE International
Magnetics Conference (InterMAG 2006), FB-10, San Diego, California, USA, (2006).
21. T. C. Chong, L. P. Shi, X. S. Miao, P. K. Tan, X. Hu and J. M. Li, “Multi-speed Blu-ray
disc with superlattice-like structure”, The 22nd Optical Data Storage Topical Meeting
(ODS’06), MP 12, Montreal, Canada (2006).
22. L. P. Shi, T. C. Chong, X. Hu, J. M. Li, K. C. Zhao, H. X. Yang and X. S. Miao, “Blu-ray
type super resolution near field optical disk with Sb70Te30 and Sb2Te3 mask layer”,
The 22nd Optical Data Storage Topical Meeting (ODS’06), MP 9, Montreal, Canada,
(2006).
23. M. H. Hong, Y.Lin, C. S. Lim, G. X. Chen, K. S. Tiaw, L. S. Tan, L. P. Shi and T. C.
Chong, “Parallel sub-micron surface processing with laser irradiation through a
microlens array”, International Congress on Laser Advanced Materials Processing, (May
2006, Kyoto, Japan), #06-43.
24. Q. Xie, M. H. Hong, B. C. Lim, K. S. Tiaw, L. P. Shi and T. C. Chong, “Open circuit
repairing by laser-induced plasma-assisted ablation on transparent material”,
International Congress on Laser Advanced Materials Processing, (May 2006, Kyoto,
Japan), #06-131.
25. B. C. Lim, M. H. Hong, A. Kaur, L. P. Shi and T. C. Chong, “Laser cleaning of
contaminations with the aid of freezer”, International Congress on Laser Advanced
Materials Processing, (May 2006, Kyoto, Japan), #06-80.
26. X. Hu, L. P. Shi, E. K. Chua, W. W. Wang, X. S. Miao and T. C. Chong, “Dual-speed 25GB
inorganic write-once disk with low-to-high polarity”, Digest of ISOM 2006, 118, (2006).
27. J. M. Li, L. P. Shi, H. X. Yuan, K. G. Lim, X. S. Miao and T. C. Chong, “Local Thermal
Expansion in Super Resolution Near Field Structure”, Digest of ISOM 2006, 180, (2006).
28. L. P. Shi, T. C. Chong, X. S. Miao, X. Hu, G. Q. Yuan, H. F. Yuan, L. H. Ting, J. M. Li, L.
T. Ng and W. L. Tan, “ Multi-dimensional Multi-level Optical Recording”, Digest of ISOM
2006, 226, (2006).
29. T. C. Chong, R. Zhao, L. P. Shi, H. X. Yang, H. K. Lee and K. G. Lim, “Superlattice-like
phase change random access memory”, Digest of E*PCOS 2006, France, Grenoble,
(2006).
Invited
PUBLICATIONS
30. R. Zhao, L. P. Shi, E. G. Yeo, K. G. Lim, H. K. Lee, W. J. Wang, H. X. Yang, and T.C.
Chong, “Nano-phase change random access memory (PCRAM) fabrication by a hybrid
of e-beam and optical lithography”, MRS Meeting Fall 2006, (2006).
31. B. S. Luk`yanchuk, Z. B. Wang, M. H. Hong, L. P. Shi, and T. C. Chong, “Processing
with lasers beyond the diffraction limit: theoretical aspects”, Abstracts of E-MRS Spring
Meeting, Nice, France, May 29-June 2, 2006, p. H-2 (2006).
32. B. S. Luk`yanchuk, W. D. Song, Z. B. Wang, M. H. Hong, T. C. Chong, J. Graf, M.
Mosbacher, P. Leiderer, “New methods for laser cleaning of nanoparticles”, Abstracts
of Workshop on Laser Interface Interactions and Laser Cleaning, LIILAC 2006, Konstanz,
Germany, June 4-7, (2006).
33. B. S. Luk`yanchuk, Z. B. Wang, M. H. Hong, L. P. Shi, T. C. Chong, “Processing with
lasers beyond the diffraction limit: theoretical aspects”, Abstracts of International
Conference “Advanced Laser Technologies” (ALT`06), September 8-12, 2006, Brasov,
Romania.
34. B. X. Xu, H. X. Yuan, Q. D. Zhang, J. Zhang, R. Ji and T. C. Chong, “Interface thermal
issue study in heat assisted magnetic recording (Invited talk)”, MORIS’2006 Workshop
on Thermal & Optical Magnetic Materials and Devices, 6-8 June, 2006, Chiba, Japan.
35. L.P. Shi and T.C. Chong, 8 th International TBOC Workshop, “Research status of nano
material and nano particle for storage in DSI” July 27, Seoul, Korea (2006).
36. D. Eversole, G. Xun, B. S. Luk`yanchuk B. S., A. Ben-Yakar, “Femtosecond laser
plasmonic ablation by gold nanoparticles”, Abstract of SPIE Photonics West
Conference, January 20–25, 2007, San-Jose, California USA, Invited Lecture.
37. L. P. Shi, T. C. Chong, X. S. Miao, J. M. Li, H. F. Wang, B. S. Luk`yanchuk, M. H.
Hong, “Surface plasmon in super resolution near field optical recording”, Abstracts of
International Workshop “Plasmonics and applications in nanotechnologies”, December
5-7, 2006, Singapore, p. 40.
38. H. X. Yuan, B. X. Xu, B. S. Luk’yanchuk, T. C. Chong, “Nano-scale surface plasmonbased optical transducer for HAMR optical head”, Abstracts of International Workshop
“Plasmonics and applications in nanotechnologies”, December 5-7, 2006, Singapore, p.
80.
39. H. F. Wang, B. X. Xu, B. S. Luk’yanchuk, T. C. Chong, “Polarization response of metal
nano-spheres”, Abstracts of International Workshop “Plasmonics and applications in
nanotechnologies”, December 5-7, 2006, Singapore, p. 83.
40. W. C. H. Ong, M. Fang, C. H. Liu, Z. Yi, M. H. Hong, B. S. Luk’yanchuk,
“Thermal annealing effects on the surface-enhanced Raman spectra of Ni81Fe19
nanoparticles”, Abstracts of International Workshop “Plasmonics and applications in
nanotechnologies”, December 5-7, 2006, Singapore, p. 84.
Invited
85
PUBLICATIONS
86
41. B. S. Luk`yanchuk, M. Tribelsky, V. Ternovsky, Z. B. Wang, Y. Zhou, M. H. Hong, L.
P. Shi, T. C. Chong, “Localized plasmons in weakly dissipating materials”, Abstracts of
International Workshop “Plasmonics and applications in nanotechnologies”, December
5-7, 2006, Singapore, p. 92.
42. B. S. Luk`yanchuk, M. I. Tribelsky, V. Ternovsky, Z. B. Wang, M. H. Hong, L. P. Shi,
T. C. Chong, “Peculiarities of light scattering by nanoparticles and nanowires near
plasmon resonance frequencies in weakly dissipating materials”, Abstracts of the 1st
European Topical Meeting on Nanophotonics and Metamaterials, January 8-11, 2007,
Seefeld, Tirol, Austria.
43. Chong Tow Chong, Shi Luping, Zhao Rong, “Engineering phase change materials by
superlattice-like structure and its applications”, Workshop on Super-RENS, Plasmons,
and Surface Recording Science & Technology (ISPS2007).
44. Loh Huan Qian, “Atoms in a cavity: a source of narrowband photon pairs”, APS March
Meeting 2007.
45. Xu Baoxi, Hu Shengbin, Yuan Hongxing, Zhang Jun, Chen Yunjie, Ji Rong, Miao
Xiangshui, Chen Jingsheng, Chong Tow Chong, “Thermal effects of heated magnetic
disk on the slider in heat assisted magnetic recording”, Journal of applied physics, Vol.
00 # 8, pp08N102-1 to 08N102-3, 2006.
46. Shi Luping, Chong Tow Chong, Hu Xiang, Li Jianming, K.C. Zhao, Yang Hongxin,
Miao Xiangshui, “Blu Ray Type Super Resolution Near Field Optical Disk with Sb70Te30
or Sb2Te3 Mask Layer”, Optical Data Storage Topical Meeting (ODS’06), pp70-72, 2006.
47. Shi Luping, Chong Tow Chong, Hu Xiang, Li Jianming, Miao Xiangshui, Yang
Hongxin, Lim Kian Guan, K C Zhao, G Y Li, “Blu Ray Type Super Resolution Near Field
Optical Disk with Sb2Te3 Mask Layers and a thermal shield layer in front of the mask
layer”, SPIE proceedings, Vol. 6282, pp62821U-1 to 62821U-8, 2006.
48. Xu Baoxi, Yuan Hongxing, Zhang Qide, Zhang Jun, Ji Rong, Chong Tow Chong,
“Interface thermal issue study in heat assisted magnetic recording”, Workshop on
Thermal & Optical Magnetic Materials and Devices (MORIS 2006), 2006.
49. X S Miao, L P Shi, P K Tan, J M Li, K G Lim, X Hu, T C Chong, “Initialization-free
multispeed blue laser optical disc”, Japanese journal of applied physics, Vol. 45 # 8A,
pp6337-6339, 2006.
50. Yuan Hongxing, Xu Baoxi, Wang Haifeng, Chong Tow Chong, “Roles and
contributions of surface plasmons, evanescent modes and propagation modes for
near-field enhancement of nano-slit”, Japanese journal of applied physics, Vol. 45 # 9A,
pp6974-6980, 2006.
51. Shi Luping, Chong Tow Chong, “Nanophase change for data storage application”,
Journal of nanoscience and nanotechnology, Vol. 7 # 2, pp65-93, 2007.
Invited
PUBLICATIONS
Spintronics, Media And Interface Division
1.
Jalil.M.B.A, S.G.Tan, B.K.A.S.Pillay, S.Bae, “Spin drift diffusion studies of
magnetoresistance effects in current-perpendicular-to-plane spin-valves with halfmetallic insertions”, Physical review B, Vol.73, No.13, Apr 2006.
2.
S.Bae, S.G.Tan, Jalil.M.B.A, B.KA.S.Pillay, K.L.Teo. Z.Y.Leong, Thomas.Y.F.Liew,
“Magnetoresistive behavior of current-perpendicular-to-plane trilayer with half-metal
insertions”, Journal of Applied Physics, Vol.99, No.8, Apr 2006.
3.
Viloane.K, M.G.Sreenivasan, Y.F.Liew, T.C.Chong, “Molecular-beam epitazy growth
and magnetic properties of BeTe with Cr doping”, Journal of applied physics, Vol.99,
No.8, Apr 2006.
4.
G.Han, Y.H.Wu, Y.K.Zheng, “Quadrupole magnetic force microscopy tip and its
imaging performance”, 2006 MRS Spring Meeting, 2006.
5.
J.J.Qiu, G.C.Han, K.B.Li, Z.Y.Liu, B.Y.Zong, Y.H.Wu, “The influence of nano-oxide layer
on magnetostriction of sensing layer in bottom spin valves”, Journal of applied physics,
Vol.99, No.9, May 2006.
6.
G.Han, Y.H.Wu, Y.K.Zheng, “A multilayer magnetic force microscopy tip and
comparison of its imaging performance with conventional tips”, IEEE International
Magnetics Conference (INTERMAG 2006), 2006.
7.
Maureen.Tay, “Cobalt-doped zinc oxide : dilute magnetic semiconductor or
inhomogeneous ferromagnet?”, IEEE International Magnetics Conference (INTERMAG
2006), 2006.
8.
Y.K.Zheng, J.J.Qiu, K.B.Li, G.C.Han, Z.B.Guo, P.Luo, L.H.An, Z.Y.Liu, Y.H.Wu,
B.Liu, “Spin-flop switching of the guided synthetic anti-ferromagnet MRAM”, IEEE
International Magnetics Conference (INTERMAG 2006), 2006.
9.
Z.Y.Liu, G.C.Han, Y.K.Zheng, “A heat interaction investigation in thermally assisted
MRAM”, IEEE International Magnetics Conference (INTERMAG 2006), 2006.
10. J.F.Hu, J.S.Chen, B.C.Lim, T.J.Zhou, “(002) oriented FeCo films as a soft magnetic
underlayer for L10 ordered FePt perpendicular media”, IEEE International Magnetics
Conference (INTERMAG 2006), 2006.
11. B.K.Tan, B.Liu, Y.S.Ma, S.F.Ling, “Effect of slider trailing pad size on lubricant transfer”,
IEEE International Magnetics Conference (INTERMAG 2006), 2006.
12. S.G.Tan, Jalil.M.B.A, B.K.A.S.Pillay, K.L.Teo, Y.K.Zheng, Thomas.Y.F.Liew, “Electrical
control of ballistic spin-dependent conductance through magneto-electric barriers in
the 2D-electron gas of GaAs heterostructure”, IEEE International Magnetics Conference
(INTERMAG 2006), 2006.
87
88
PUBLICATIONS
13. B.K.A.S.Pillay, Jalil.M.B.A, S.G.Tan, K.L.Teo, “MR enhancemet in CPP spin valve by
insertion of a ferromagnetic layer within the spacer layer”, IEEE International Magnetics
14. B.K.A.S.Pillay, Jalil.M.B.A, S.G.Tan, Rachel.Ng, “The effect of spreading resistance on
the magnetoresistance of current-perpendicular-to-plane spin valves with patterned
spacer layers”, IEEE International Magnetics Conference (INTERMAG 2006), 2006.
15. J.Z.Shi, S.N.Piramanayagam, S.Y.Chow, J.M.Zhao, C.S.Mah, “CoCrPt SiO2
perpendicular recording media with a crystalline soft underlayer”, IEEE International
16. J.S.Chen, Y.F.Ding, B.C.Lim, “Nanogranular L10 FePt:C Composite films for
perpendicular recording”, IEEE International Magnetics Conference (INTERMAG 2006),
2006.
17. H.B.Zhao, J.F.Hu, J.S.Chen, “Composition and temperature dependence of
magnetic and structural properties of nanocrystalline FeTaC soft magnetic films”, IEEE
18. Y.K.Zheng, G.C.Han, K.B.Li, Z.B.Guo, J.J.Qiu, S.G.Tan, Z.Y.Liu, B.Liu, Y.H.Wu,
“Side-shielded TGMR reader with track width reduction scheme”, IEEE International
19. H.K.Lee, Z.M.Yuan, “Enhancement of Recording using Magnetic Resonance”, IEEE
20. K.W.Ng, Z.M.Yuan, B.Liu, T.C.Chong, “Reduction of crown sensitivity on disk shape
induced flying height variation through ABS design”, IEEE International Magnetics
21. B.Y.Zong, G.C.Han, Y.K.Zheng, K.B.Li, Z.B.Guo, J.J.Qiu, Z.Y.Liu, L.H.An, P.Luo, L.H.Li,
B.Liu, “Ultra-soft and high magnetic moment NiFe films prepared via electrodeposition
from A Cu2+ contained solution”, IEEE International Magnetics Conference (INTERMAG
2006), 2006.
22. B.C.Lim, J.F.Hu, J.S.Chen, S.Y.Chow, G.M.Chow, “Interface effect of MgO intermediate
layer on the perpendicular anisotrophy of L10FePt films and the initial growth layer”,
IEEE International Magnetics Conference (INTERMAG 2006), 2006.
23. S.N.Piramanayagam, J.Z.Shi, C.S.Mah, J.Zhang, “A novel perpendicular recording
medium with a magnetic intermediate layer”, IEEE International Magnetics Conference
(INTERMAG 2006), 2006.
24. S.H.Leong, Z.M.Yuan, K.W.Ng, B.Liu, “On-spot (n, k) compensation by CCD for
precision optical flying height measurement”, IEEE International Magnetics Conference
(INTERMAG 2006), 2006.
PUBLICATIONS
25. G.C.Han, K.B.Li, Y.K.Zheng, J.J.Qiu, P.Luo, L.H.An, Z.B.Guo, Z.Y.Liu, Y.H.Wu,
“Fabrication of sub-50nm current-perpendicular-to-the plane spin valve sensors”, Thin
solid films, Vol.505, No.1-2, pp41-44, May 2006.
26. G.C.Han, P.Luo, S.J.Wang, M.Tay, Z.B.Guo, Y.H.Wu, F.U.Nahar, “Co-doped TiO2
epitaxial thin films grown by sputtering”, Thin solid films, Vol.505, No.1-2, pp137-140,
May 2006.
27. B.C.Lim, J.S.Chen, J.H.Yin, “Reduction of exchange coupling and enhancement of
coercivity of L10 FePt (001) films by Cu toping layer diffusion”, Thin solid films, Vol.505,
No.1-2, pp81-84, May 2006.
28. S.G.Tan, Jalil.M.B.A, V.Kumar, Thomas.Y.F.Liew, K.L.Teo, T.C.Chong, “Transistor
device for multi-bit non-volatile storage”, Thin solid films, Vol.505, No.1-2, pp60-63, May
2006.
29. J,Liu, M.S.Zhang, B.Liu, J.P.Yang, “Active slider for flying height adjustment”, 3rd
Asia-Pacific Conference of Transducers and Micro-Nano Technology (APCOT 2006), Jun
2006.
30. W.Hua, B.Liu, “Mechanism studies of the multiple flying states of the air bearing
slider”, Tribology international, Vol.39, No.7, pp649-656, Jul 2006.
31. Y.S.Ma, B.Liu, W.J.Wang, K.D.Ye, “Slider-bump contact and flying height calibration”,
Tribology letters, Vol.23, No.1, pp83-91, Jul 2006.
32. C.Y.Tan, J.S.Chen, B.H.Liu, G.M.Chow, “Microstructure of FePt nanoparticles
produced by nanocluster beam”, Journal of crystal growth, Vol.293, No.1, pp175-185,
Jul 2006.
33. H.M.Wang, Y.H.Wu, K.S.Choong, J.Zhang, K.L.Teo, Z.H.Ni, Z.X.Shen, “Disorder
induced bands in first order Raman spectra of carbon nanowalls”, IEEE-Nano2006, Jul
2006.
34. V.Ko, K.L.Teo, T.Y.F.Liew, T.C.Chong, “Ferromagnetic ordering and extraordinary hall
effect in epitaxial Co-doped germanium”, 28th International Conference on the Physics
of Semiconductors, 2006.
35. V.Ko, K.L.Teo, Thomas.Y.F.Liew, T.C.Chong, “Ferromagnetic and anomalous hall effect
in CoxGe1-x”, Applied physics letters, Vol.89, No.4, Jul 2006.
36. Y.S.Ma, B.K.Tan, B.Liu, “Lubricant transfer and slider-lubricant interaction at ultra-low
flying height”, Journal of magnetism and magnetic materials, Vol.303, No.2, ppe110114, Aug 2006.
37. S.G.Tan, Jalil.M.B.A, Thomas.Y.F.Liew, K.L.Teo, “Green’s function approach to
calculate spin injection in quantum dot”, Journal of magnetism and magnetic
materials, Vol.303, No.2, ppe322-e324, Aug 2006.
89
PUBLICATIONS
90
38. Jalil.M.B.A, S.G.Tan, “Theoretical model of spin transfer torque in multilayers”, Journal
of magnetism and magnetic materials, Vol.303, No.2, pp333-337. Aug 2006.
39. Z.B.Guo, Y.K.Zheng, K.B.Li, G.C.Han, Z.Y.Liu, J.J.Qiu, P.Luo, L.H.An, Y.H.Wu,
“Saturation field direction dependence of domain structures in NiFe elements”, Solid
state communications, Vol.139, No.8, Aug 2006.
40. Y.F.Ding, J.S.Chen, E.Liu, L.Li, “L10 FePt films epitaxially grown on MgO substrates
with or without Cr underlayer”, Journal of magnetism and magnetic materials, Vol.303,
No.2, ppe238-e242, Aug 2006.
41. J.S.Chen, B.C.Lim, Y.F.Ding, G.M.Chow, “Low temperature deposition of L10 FePt
films for ultra high density magnetic recording”, Journal of magnetism and magnetic
materials, Vol.303, No.2, pp309-317, Aug 2006.
42. H.L.Li, H.T.Lin, Y.H.Wu, T.Liu, Z.L.Zhao, G.C.Han, T.C.Chong, “Magnetic and electrical
transport properties of delta-doped amorphous Ge:Mn magnetic semiconductors”,
Journal of magnetism and magnetic materials, Vol.303, No.2, ppe318-e321, Aug 2006.
43. L.Wang, G.C.Han, Y.K.Zheng, “Anatomy of field effects on magnetization dynamics
and spin transfer noise”, Journal of magnetism and magnetic materials, Vol.303, No.2,
ppe172-e175, Aug 2006.
44. S.N.Piramanyagam, Z.J.Shi, C.K.Pock, C.S.Mah, J.M.Zhao, J.Zhang, Y.S.Kay, L.Lu,
C.Y.Chun, “Novel intermediate layers for high density CoCrPT:oxide perpendicular
recording media”, 17th Magnetic Recording Conference (TMRC 2006) (International
Conference on Perpendicular Magnetic Recording), 2006.
45. Y.K.Zheng, G.C.Han, K.B.Li, J.J.Qiu, Z.B.Guo, P.Luo, L.H.An, S.G.Tan, Z.Y.Liu,
“Scalable toggle read head towards Tbits/in2”, 17th Magnetic Recording Conference
(TMRC 2006) (International Conference on Perpendicular Magnetic Recording), 2006.
46. B.Liu, H.Li, J.Liu, L.Gonzaga, Y.S.Ma, S.K.Yu, M.S.Zhang, Y.J.Man, T.C.Chong,
“Criteria and design strategy towards highly stable head-disk interface at ultra-low
flying height”, 17th Annual Magnetic Recording Conference (TMRC 2006), 2006.
47. M.Tay, Y.H.Wu, G.C.Han, Y.K.Zheng, T.C.Chong, Y.B.Chen, X.Q.Pan, “Characterization
of inhomogeneous cobalt doped zinc oxide films”, 17th International Conference on
Magnetism (ICM 2006), 2006.
48. Z.Y.Leong, S.G.Tan, Jalil.M.B.A, B.K.A.S.Pillay, G.C.Han, “Suppressed
magnetoresistance in CPP spin valve with insertion of interfacial resistance”, 17th
International Conference on Magnetism (ICM 2006), 2006.
49. Jalil.M.B.A, S.G.Tan, B.K.A.S.Pillay, Z.Y.Leong, “Spin accumulation and
magnetoresistance in multilayers with non-collinear magnetization”, 17th International
Conference on Magnetism (ICM 2006), 2006.
Invited
PUBLICATIONS
50. Y.Z.Law, S.Bae, Y.B.Choi, T.C.Chong, “Perpendicular anisotropy and giant
magnetoresistance in sputtered Co/Cu superlattices”, 17th International Conference on
Magnetism (ICM 2006), 2006.
51. G.C.Han, Eileen Tan, B.Y.Zong, K.B.Li, B.Liu, Y.H.Wu, “Temperature dependence of
thermally activated ferromagnetic resonance in tunneling magnetoresistive heads”,
Asia-Pacific Data Storage Conference (APDSC ‘06), 2006.
52. J.Z.Shi, S.N.Piramanyagam, J.M.Zhao, C.S.Mah, B.Liu, “High writability
perpendicular recording media with low noise crystalline soft underlayer”, Asia-Pacific
Data Storage Conference (APDSC ‘06), 2006.
53. S.G.Tan, Jalil.M.B.A, B.K.A.S.Pillay, G.C.Han, Y.K.Zheng, “Layer thickness effect on
the magnetoresistance of a current-perpendicular-to-plane spin valve”, Journal of
applied physics, Vol.100, No.6, 2006.
54. G.C.Han, T.C.Chong, Y.K.Zheng, S.J.Wang, Y.B.Chen, X.Q.Pan, “Ferromagnetism in
inhomogeneous Zn1-xCoxO thin films”, Journal of applied physics, Vol.100, 2006.
55. G.C.Han, Y.K.Zheng, Z.Y.Liu, B.Liu, S.N.Mao, “Field dependence of high frequency
magnetic noise in tunneling magnetoresistive heads”, Journal of applied physics,
Vol.100, No.6, 2006.
56. S.H.Leong, Z.M.Yuan, K.W.Ng, B.Liu, “On-spot (n, k) compensation by CCD for
precision optical flying height measurement”, IEEE Transactions on Magnetics, Vol.42,
No.10, 2006.
57. S.G.Tan, Jalil.M.B.A, B.K,A.S.Pillay, K.L.Teo, Y.K.Zheng, Y.F.Liew, “Electrical control
of ballistic spin-dependent conductance through the 2D-electron gas of GaAs
heterostructure”, IEEE transactions on magnetics, Vol.42, No.10, 2006.
58. B.K.A.S.Pillay, S.G.Tan, Jalil.M.B.A, K.L.Teo, “MR enhancement in current
perpendicular-to-plane spin-valve by insertion of a ferromagnetic layer within the
spacer layer”, IEEE transactions on magnetics, Vol.42, No.10, pp2459-2461, 2006.
59. J.S.Chen, Y.F.Ding, B.C.Lim, E.J.Liu, “Nanogranular L10 FePt:C composite films for
perpendicular recording”, IEEE transactions on magnetics, Vol.42, No.10, pp2363-2365,
2006.
60. B.Y.Zong, G.C.Han, Y.K.Zheng, Z.B.Guo, K.B.Li, L.Wang, J.J.Qiu, Z.Y.Liu, L.H.An,
P.Luo, H.L.Li, B.Liu, “Ultrasoft and high magnetic moment NiFe film electrodeposited
from a Cu2+ contained solution”, IEEE transactions on magnetics, Vol.42, No.10,
pp2775-2777, 2006.
61. B.C.Lim, J.S.Chen, G.M.Chow, “Interfacial effects of MgO buffer layer on
perpendicular anisotrophy of L10 FePt films”, IEEE transactions on magnetics, Vol.42,
No.10, pp3017-3019, 2006.
91
PUBLICATIONS
92
62. S.N.Piramanyagam, C.K.Pock, L.Lu, C.Y.Ong, J.Z.Shi, C.S.Mah, “Grain size reduction
in CoCrPt:SiO² perpendicular recording media with oxide-based intermediate layers”,
Applied physics letters, Vol.89, No.16, 2006.
63. Y.K.Zheng, K.B.Li, J.J.Qiu, Z.B.Guo, G.C.Han, P.Luo, L.H.An, S.G.Tan, Z.Y.Liu,
L.Wang, B.Y.Zong, B.Liu, “High density flash-like cross-point MRAM”, 8th International
Conference on Solid-State and Integrated-Circuit Technology (ICSICT-2006), 2006.
64. B.K.A.S.Pillay, Jalil.M.B.A, S.G.Tan, Z.Y.Leong, “Magnetoresistance effects arising
from interfacial resistance in a current-perpendicular-to-plane spin-valve trilayer”,
Physical review B, Vol.74, No.18, 2006.
65. B.K.A.S.Pillay, Jalil.M.B.A, S.G.Tan, R.Ng, Y.F.Liew, “The effect of spreading resistance
on the magnetoresistance of current-perpendicular-to-plane spin valves with
patterned layers”, IEEE transactions on magnetics, IEEE transactions on magnetics,
Vol.42, No.1, pp3788-3790, 2006.
66. B.Liu, M.S.Zhang, S.K.Yu, Y.J.Man, L.Gonzaga, “Low flying height technology
for ultra high density data storage”, 8th Asian Symposium on Information Storage
Technology (ASIST-8), Vol.106, No.335, pp19-20, 2006.
67. H.L.Li, Y.H.Wu, Z.B.Guo, P.Luo, S.J.Wang, “Magnetic and electrical transport
properties of Ge1-xMnx thin films”, Journal of applied physics, Vol.100, No.10, 2006.
68. L.Gonzaga, B.Liu, “Altitude-insensitive femto slider design”, Asia-Pacific Magnetic
Recording Conference (APMRC ‘06), 2006.
69. M.S.Zhang, C.H.Wong, S.K.Yu, B.Liu, “Flying stability of a thermal actuated slider”,
Asia-Pacific Magnetic Recording Conference (APMRC ‘06), 2006.
70. Y.S.Ma, B.Liu, “Lubricant transfer from disk to slider”, Asia-Pacific Magnetic Recording
Conference (APMRC ‘06), 2006.
71. B.Liu, M.S.Zhang, Y.J.Man, S.K.Yu, L.Gonzaga, Y.S.Ma, F.Tjiptoharsono, “Air-bearing
design towards super stable head-disk interface”, Asia-Pacific Magnetic Recording
Conference (APMRC ‘06), 2006.
72. J.M.Zhao, S.N.Piramanayagam, J.Z.Shi, J.Zhang, Y.S.Kay, “Parametric optimization
of tape-burnish process for perpendicular recording media of hard disk drive”, AsiaPacific Magnetic Recording Conference (APMRC ‘06), 2006.
73. W.Hua, B.Liu, S.K.Yu, W.D.Zhou, “Simulation of nanometer spaced air bearing slider
with complex rail shape”, Asia-Pacific Magnetic Recording Conference (APMRC ‘06),
2006.
74. W.D.Zhou, B.Liu, S.K.Yu, W.Hua, “Simulation of air bearing pressure on discrete track
recording media”, Asia-Pacific Magnetic Recording Conference (APMRC ‘06), 2006.
Invited
PUBLICATIONS
75. S.K.Yu, B.Liu, W.Hua, W.D.Zhou, “Roughness contact and dynamic stability of
read/write head positioning in both flying-height and off-track directions”, Asia-Pacific
Magnetic Recording Conference (APMRC ‘06), 2006.
76. Y.S.Ma, B.Liu, “Consideration and compensation for precision optical flying height
measurement”, Tribology letters, Vol.25, No.1, pp79-85, 2007.
77. R.Sbiaa, S.N.Piramanayagam, “Patterned media towards nano-bit magnetic
recording : fabrication & challenges”, Recent patents on nanotechnology, Vol.1, No.1,
pp29-40, 2007.
L.Wang, B.Y.Zong, B.Liu, “Scalable toggle read head towards Tbits/in2”, IEEE
transactions on magnetics, Vol.43, No.2, pp657-662, 2007.
79. Y.K.Zheng, Y.H.Wu, K.B.Li, J.J.Qiu, G.C.Han, Z.B.Guo, P.Luo, L.H.An, Z.Y.Liu,
L.Wang, S.G.Tan, B.Y.Zong, B.Liu, “Magnetic random access memory (MCRAM)”,
Journal of nanoscience and nanotechnology, Vol.7, No.2, pp117-137, 2007.
80. Jalil.M.B.A, S.G.Tan, X.Z.Cheng, “Advanced modeling techniques for micromagnetic
systems beyond the standard model”, Journal of nanoscience and nanotechnology,
Vol.7, No.2, pp46-64, 2007.
81. J.S.Chen, B.C.Lim, J.F.Huang, Y.K.Lim, B.Liu, G.M.Chow, “High coercivity L10
FePt films with perpendicular anisotropy deposited on glass substrate reduced
temperature”, Applied physics letters, Vol.90, No.4, 2007.
82. Z.Y.Liu, G.C.Han, Y.K.Zheng, “A heat interaction investigation in thermally assisted
MRAM”, IEEE transactions on magnetics, Vol.42, No.10, pp2715-2717, 2006.
83. Sunny.Y.H.Lua, Y.H.Wu, K.L.Teo, T.C.Chong, “Transport study of domain walls
induced by an exchange tab in magnetic nanowires”, 2006 MRS Fall Meeting, 2006.
84. J.Z.Shi, S.N.Piramanayagam, J.M.Zhao, C.S.Mah, C.Ong, “Low-noise crystalline soft
underlayer for CoCrPt:SiO2 perpendicular recording media”, 10th Joint MMM/Intermag
Conference (MMM 2007), 2007.
85. J.Z.Shi, L.Q.Qiu, S.N.Piramanayagam, J.M.Zhao, C.S.Mah, C.Ong, J.S.Chen, J.Ding,
“Exchange coupled composite media with soft layer below the hard layer for CoCrPt:
SiO2 perpendicular recording media”, 10th Joint MMM/Intermag Conference (MMM
2007), 2007.
L.Wang, B.Y.Zong, B.Liu, “Highly sensitive long-height reader with toggle mode”, 10th
Joint MMM/Intermag Conference (MMM 2007), 2007.
87. Y.K.Zheng, J.J.Qiu, P.Luo, L.H.An, k.B.Li, G.C.Han, Z.B.Guo, S.G.Tan, Z.Y.Liu, B.Liu,
“Thermal stability and writing margin of the multi-layer GSAF MRAM”, 10th Joint
MMM/Intermag Conference (MMM 2007), 2007.
Invited
93
PUBLICATIONS
94
88. J.Zhang, R.Ji, J.W.Xu, J.K.P.Ng, B.X.Xu, H.X.Yuan, S.N.Piramanyagam, Y.F.Liew,
“Study of lubricant pickup at the head-disk interface under laser irradiation”, 10th Joint
MMM/Intermag Conference (MMM 2007), 2007.
89. L.Wang, G.C.Han, Y.K.Zheng, B.Liu, “Simulation and stability analysis of current and
transverse field effects on spin transfer noise”, 10th Joint MMM/Intermag Conference
(MMM 2007), 2007.
90. M.S.Zhang, B.Liu, Y.J.Man, “High selectivity etching for texture fabrication on air
bearing surface”, 10th Joint MMM/Intermag Conference (MMM 2007), 2007.
91. B.Liu, S.K.Yu, M.S.Zhang, L.Gonzaga, “Mean-plane spacing limit and slider
technology for fully stable head-disk interface under various working condition”, 10th
Joint MMM/Intermag Conference (MMM 2007), 2007.
92. S.N.Piramanayagam, J.Z.Shi, K.Srinivasan, R.Sbiaa, C.S.Mah, C.Y.Ong,
J.M.Zhao, Y.S.Kay, J.Zhang, “Novel approaches towards high density CoCrPt-oxide
perpendicular recording media”, 10th Joint MMM/Intermag Conference (MMM 2007),
2007.
93. B.K.Tan, B.Liu, Y.S.Ma, M.S.Zhang, S.F.Ling, “Effect of electrostatic force on sliderlubricant interaction”, 10th Joint MMM/Intermag Conference (MMM 2007), 2007.
94. S.K.Yu, B.Liu, W.Hua, W.D.Zhou, “Contact induced off-track vibrations of air bearingslider-suspension system in hard disk drives”, STLE/ASME International Joint Tribology
Conference, 2006.
95. L.Wang, G.C.Han, Y.H.Wu, “Thickness dependence of giant magnetoresistance in spin
valves : influence of interface and bulk scattering”, IEEE transactions on magnetics,
Vol.43, No.2, pp506-509, 2007.
96. P.Y.Xiao, Z.M.Yuan, H.K.Lee, G.X.Guo, “Bit-array alignment effect of perpendicular
SOMA media”, Journal of magnetism and magnetic materials, Vol.303, No.2, 2006.
97. Y.J.Man, S.K.Yu, B.Liu, “Characterization and formation mechanism understanding
of asperities to be burnished”, Journal of magnetism and magnetic materials, Vol.303,
No.2, 2006.
98. Y.P.Zhou, B.Liu, L.W.Li, “Evaluation of gap length fluctuation with harmonic analysis
method”, Journal of magnetism and magnetic materials, Vol.303, No.2, 2006.
99. S.N.Piramanayagam, J.Z.Shi, H.B.Zhao, C.K.Pock, C.S.Mah, C.Y.Ong, J.M.Zhao,
J.Zhang, Y.S.Kay, L.Lu, “Magnetic and microstructural properties of CoCrPt: oxide
perpendicular recording media with novel intermediate layers”, IEEE transactions on
magnetics, Vol.43, No.2, 2007.
100. J.Z.Shi, S.N.Piramanayagam, J.M.Zhao, C.S.Mah, B.Liu, “High writability
perpendicular recording media with low noise crystalline soft underlayer”, IEEE
transactions on magnetics, Vol.43, No.2, pp873-875, 2007.
Invited
PUBLICATIONS
101. W.C.Poh, S.N.Piramanayagam, J.R.Shi, Y.F.Liew, “Novel hybrid facing targets
sputtered amorphous carbon overcoat for ultra-high density hard disk media”,
Diamonds and related materials, Vol.16, No.2, pp379-387, 2007.
102. H.K.Lee, Z.M.Yuan, “Studies of the magnetization reversal process driven by an
oscillating field”, Journal of applied physics, Vol.101, No.3, 2007.
103. S.G.Tan, Jalil.M.B.A, B.K.A.S.Pillay, “Influence of spin relaxation on
magnetoresistance”, Journal of applied physics, Vol.101, No.4, 2007.
95
patents
96
intellectual capital
patents
Filing of patents remain
an important strategy for
DSI as we develop and
innovate. The transfer of
technology is facilitated via
Exploit Technologies, the
Commercialisation/Licensing
arm of A*STAR. The complete
listing of our patent portfolio
is as follows.
Republic of Singapore
Filed
Malaysia
Granted
Filed
07 10 01
Thailand
Taiwan
Filed
01
Filed
Japan Korea
Filed
04
Filed
Patent Corporation Treaty
United States of America
Filed
Filed
04
Granted
02 01
01
Granted
12 02
patents
Patents Filed
An Artificial Planar Medium Structure
Voice Coil Motor
A High Performance Voice Coil Motor Structure Used in Hard Disk Drive
Perpendicular Magnetic Recording Media
A Method to Reduce Grain Size in Double-Layered Perpendicular Magnetic Recording
Medium)
Double-layered Perpendicular Magnetic Recording Media
(Noise Reduction in Crystalline Soft underlayer for Perpendicular Magnetic Recording
Media)
Scalable transducer
(Scalable transducer with a synthetic anti-ferromagnet free layer in toggle mode)
Low temperature deposition of chemically ordered FePt perpendicular recording media
A File System For A Storage Device, Methods OF Allocating Storage, Searching Data And
Optimising Performance Of A Storage Device File System
(Adaptive Data Allocation and Management Algorithm in a Storage Device)
Method and Apparatus for forming a uniform lubricant film on magnetic hard disk
High Density Optical Data Storage System
A Low Profile Spindle Motor
(A Low Profile Permanent Magnet Synchronous Motor)
A Method and Apparatus for cleaning Solid Surfaces
Electrically Writeable and Erasable Memory Medium
Novel Phase Change Magnetic Material
A Method And System for Obtaining n and k Map for Measuring Fly-height
High Repetition Rate Laser Module
Transportation Protocol
Method And Tester For Optical Flying Height Measurement
Memory Cells And Devices Having Magnetoresistive Tunnel Junction With Guided
Magnetic Moment Switching And Method
Tilted Media for Hard Disk Drive
Balancing Apparatus and Method
Magnetic Memory Device
97
patents
98
Nano-Contacted Magnetic Memory Device
Magneto-electric Field Effect Transistor for Spintronic Applications
A Recording Medium
Patents Granted
Method of Laser Marking and Apparatus Therefor
(Old Title:Crack Free and Color Laser Printing of Transparent Hard Materials)
A Method and Apparatus for Patterning a Substrate
Method and apparatus for cutting a multi-layer substrate by dual laser irradiation
Oblique Deposition Apparatus
Method of Magnetically Patterning a Thin Film by Mask-Controlled Local Phase Transition
Method and Apparatus for Decapping Integrated Circuit Packages
(Decapping of IC Devices with a Pulsed Laser Irradiation for Failure Analysis)
Method and Apparatus for Deflashing of Integrated Circuit Packages
Magnetic Tunnel Junction Magnetic Random Access Memory Arrays
Multi-State Per Cell Magneto-Resistive Random Access Memory
A Method and Apparatus for cleaning Solid Surfaces
Titled Media For Hard Disk Drive
(Laminated Tilted Media for Hard Disk)
A Data Processing Apparatus and Method for D=2 Optical Channels
Method and Apparatus for Decapping Integrated Circuit Packages
99
INDUSTRY RELATIONS
corporate members
100
INDUSTRY RELATIONS
corporate members
corporate members
DSI’s corporate
membership scheme
facilitates close ties
between the Institute
and our industry
partners comprise
technology principals,
component suppliers
and manufacturers.
101
RESEARCH COMMUNITY
students
visiting professors
102
RESEARCH COMMUNITY
RESEARCH COMMUNITY
students
The DSI maintains close
links with our research
community which comprises
of the industry, academia and
other research institutions
as it stays true to its vision
to be a vital node in a global
generation and innovation.
Students
As DSI plays its role in nurturing research talents, our researchers
took under their wings students through industrial attachment
programmes, internships and final year projects (FYP).
Graduate – Ph.D
1.
Ashwin Kumar, Department of Electrical & Computer Engineering,
Faculty of Engineering, National University of Singapore, “Signal
detection for high-density multi-level optical recording systems”
2.
Bala Kumar A/L Sundaram Pillay, Department of Electrical &
Computer Engineering, Faculty of Engineering, National University
of Singapore, “Spintronics”
3.
Cheong Jhun Yew, School of Electrical and Electronic Engineering,
College of Engineering, Nanyang Technological University,
“Nanocluster deposition system”
4.
Fang Weiwei Lina, Department of Electrical & Computer
Engineering, Faculty of Engineering, National University
of Singapore, “Nanoscale device engineering for memory
applications”
5.
Foo Siang Meng, Department of Electrical & Computer
Engineering, Faculty of Engineering, National University of
Singapore, “Error-control coding for storage”
6.
Han Gang, Department of Electrical & Computer Engineering,
Faculty of Engineering, National University of Singapore,
“Development of high-resolution MFM tips and related
applications in magnetic imaging”
7.
Ko Viloane, A*STAR Scholars, NUS Graduate School for Integrative
Sciences & Engineering, “The MBE characterization of magnetic
semiconductor nanostructures for spintronic applications”
RESEARCH COMMUNITY
8.
Lai Chow Yin, NUS Graduate School for Integrative Sciences & Engineering, “Advanced
control technologies for future data storage systems”
9.
Law Yaozhang Dean Randall, A*STAR Scholars, NUS Graduate School for Integrative
Sciences & Engineering, “Nanofabrication of spintronic devices for high density data
storage”
10. Li Hongliang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Fabrication and characterization of nanostructured halfmetals and magnetic semiconductors”
11. Li Hui, School of Electrical and Electronic Engineering, College of Engineering, Nanyang
Technological University, “Soft intelligent sensors and its applications in magnetic data
storage systems”
12. Li Qiang, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Topology optimization of slider air bearing”
13. Lim Chin Seong, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Laser assisted fabrication of micro/nano lens arrays”
14. Liu Qing, School of Materials Science and Engineering, College of Engineering, Nanyang
Technological University, “Application of DMS material in spintronic devices”
15. Liu Xiangjun, School of Civil and Environmental Engineering, College of Engineering,
Nanyang Technological University, “Molecular dynamics and continuum mechanics based
multi-scale simulation for AFM data storage”
16. Lua Yan Hwee Sunny, A*STAR Scholars, NUS Graduate School for Integrative Sciences &
Engineering, “Fabrication and characterization of nanometer-scale magnetic structures for
data storage applications”
17. Ma Fang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Laser nanopatterning in near field”
18. Mahshid Farzinfar, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Image analysis & segmentation of 3-D confocal laser
scanned bio-objects”
103
104
RESEARCH COMMUNITY
students
19. Mambakkam Govindan Sreenivasan, Department of Electrical & Computer Engineering,
Faculty of Engineering, National University of Singapore, “MBE growth and characterization
of zinc blende half metals and diluted magnetic semiconductors”
20. Naganivetha Thiyagarajah, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Applied spintronic Devices”
21. Ng Keh Ting Doris, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Synthesis of superhydrophobic, transparent
and conductive gallium nitride nanowire networks by pulsed laser ablation”
22. Pandey Koashal Kishor Mani, Department of Materials Science, Faculty of Science,
National University of Singapore, “Structure and magnetic properties of cobalt-based binary
alloys for perpendicular recording”
23. Poh Wei Choong Allen, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Investigation of novel overcoat for ultra-high
density recording media” (Winner of 2005/2006 DSI Outstanding Student Awards)
24. Saidur Rahman Bakaul, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Spintronic devices”
25. Takashi Fujita, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Spintronics”
26. Tay Maureen, A*STAR Scholars, Department of Electrical & Computer Engineering, Faculty
of Engineering, National University of Singapore, “Growth and characterization of cobalt
doped zinc oxide films”
27. Teoh Jul Nee, A*STAR Scholars, School of Electrical and Electronic Engineering, College of
Engineering, Nanyang Technological University, “Nonlinear least-squares optimization of
sensitivity function for disturbance attentuation”
28. Thum Chin Kwan, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Advanced control technologies for future
storage systems”
RESEARCH COMMUNITY
29. Wang Haomin, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Growth and characterization of two dimensional carbon
nanostructures”
30. Wei Xiaoqian, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “High density, low power consumption, phase change
random access memory” - ( 3rd Place for APRU Enterprise Business Plan Competition – Extra
Chapter Challenge)
31. Whang Sung Jin, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Semiconductor nanowire device”
32. Zhou Yi, Department of Mechanical Engineering, Faculty of Engineering, National University
of Singapore, “Nanopatterning based-on plasmonic effect”
Graduate – Masters
1.
Chelliah Shankaran, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Technologies for 400-500 Gb/inch2
perpendicular media”
2.
Choong Kai Shin Catherine, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Selective patterning of Carbon nanowalls
and properties”
3.
Chung Nyuk Leong, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Microscopic studies of spin transfer
switching”
4.
Huang Zhiqiang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Laser mircoprocessing”
5.
Iman Mosavat, A*STAR Scholars, Department of Electrical & Computer Engineering, Faculty
of Engineering, National University of Singapore, “Detection and modeling for holographic
data storage”
105
RESEARCH COMMUNITY
106
students
6.
Lu Meihua, Department of Materials Science, Faculty of Science, National University
of Singapore, “Synthesis and characterization of FePt nanoparticles and FePt - ZnO
nanoparticle composites”
7.
Tan Boon Kee, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Interface stability study towards ultra-high density
magnetic data storage”
8.
Tan Li Sirh, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Laser nano-imprinting for 450nm and beyond”
Undergraduate - Final Year Project
1.
Aiman Bin Hussain, School of Materials Science and Engineering, College of Engineering,
Nanyang Technological University, “Research on the interaction between overcoat and
lubricant for the magnetic disk”
2.
Ang Wee Meng, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Investigation on new phase change random access
memory structure” (Merit Award for 21st Faculty of Engineering Innovation and Research
Award)
3.
Boey Yun Teng Angelina, Department of Mechanical Engineering, Faculty of Engineering,
National University of Singapore, “Dynamic thermal response of nano thin film”
4.
Bui Mao Jin Alvin, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “High anisotropy FePt-Cu thin film for ultra-high density
recording”
5.
Chan Zigeng, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Laser assisted nanostructure fabrication on shape
memory polymer”
6.
Chen Huayong Kelvin, School of Mechanical and Aerospace Engineering, College of
Engineering, Nanyang Technological University, “Identification of various vibration modes of
glide hit signal for ultra-low glide height disk”
RESEARCH COMMUNITY
7.
Chen Kaiqian, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Fabrication of carbon nanostructured materials: Growth
of carbon nanotubes”
8.
Chen Xiaokai, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Ultra-short semiconductor blue laser pulse generation”
9.
Cheong Yi-wei Alvin, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Nano-metrology and instrumentation:
Software development”
10. Cheung Pei Qiong, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Simulation of magnetic tunnel junction
devices”
11. Ching Charles Lester Lua, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Dilute magnetic semiconductors”
12. Chiong Song Ning, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Investigation on wafer thinning process
using laser ablation”
13. Chu Mingshun, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “Data security storage and transfer in internet-PC environment”
14. Chua Kian Chong, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Spindle motor system”
15. Danish Ahmed Khan, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Nano-metrology and instrumentation:
Electronics development”
16. Dao Nguyen Phu Cuong, School of Materials Science and Engineering, College of
Engineering, Nanyang Technological University, “Preparation of metal catalysts for carbon
nanotubes synthesis”
107
108
RESEARCH COMMUNITY
students
17. Do Tran Binh Minh, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Laser precision fabrication of transparent
substrate”
18. Duong Hoang Nam, School of Materials Science and Engineering, College of Engineering,
Nanyang Technological University, “Shock response analysis and novel damper
development for SFF hard disk drives”
19. Eng Weijie, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Investigation of new phase change random access
memory cell structures” (Merit Award for 21st Faculty of Engineering Innovation and
Research Award)
20. Fransiscus Jonas Salim, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Studies of tunneling behaviour in multilayer
devices”
21. Goh Chin Thing, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Hard magnetic layer for high-density perpendicular
recording media”
22. Ho Wen Yang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Auto-tuning of the head positioning servo controller of
hard disk drive”
23. Huang Chi-Chang, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Steam assisted laser ablation for surface
precision engineering”
24. Huang Jiancheng, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Investigation on nano phase change
random access memory”
25. Huang Zhaoteng Alwyn, School of Mechanical and Aerospace Engineering, College of
Engineering, Nanyang Technological University, “Dynamic and friction testing of miniature
computer hard disk drives”
RESEARCH COMMUNITY
26. Hui Wei Qiang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Performance characterization of perpendicular recording”
27. Intan Ayu Perwitasari, School of Materials Science and Engineering, College of
Engineering, Nanyang Technological University, “Investigation on nano phase change on
PCRAM cell”
28. K Khine Win, School of Materials Science and Engineering, College of Engineering, Nanyang
Technological University, “Metallic glass as recording layer for Super-RENS”
29. Ke Zhenzhou, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Dilute magnetic semiconductor for spintronic
applications”
30. Khadijah Bte Saidi, School of Materials Science and Engineering, College of Engineering,
Nanyang Technological University, “Diamond-like-carbon overcoat for magnetic disk of
computer hard disk drive”
31. Koh Di Sheng Alwyn, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Modeling of current across magnetic
multilayers”
32. Koh Yong Chuan, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Performance characterization of perpendicular recording”
33. Kua Khuan Tiong, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Energy-based control ofrResonances in hard
disk drive servo systems”
34. Lai Wanfeng, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Simulation of electromagnetic field distribution for laser
nanoimprint photolithography”
35. Lam Kok Wai, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Modeling and simulation of micro-actuation mechanism for the
head flying height adjustment in magnetic recording”
109
110
RESEARCH COMMUNITY
students
36. Lau Hui Fen, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Fast laser micro-processing of biodegradable polymers”
37. Leo Kim Ming, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Magneto tunneling channel effect”
38. Leong Yuan Shuo, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Design of regenerative power supply for
self-contained devices”
39. Li Shiqiang, Department of Materials Science & Engineering, Faculty of Engineering,
National University of Singapore, “Fabrication and Microstructure and Magnetic properties
of nanostructured magnetic films”
40. Li Yaxing, School of Electrical and Electronic Engineering, College of Engineering, Nanyang
Technological University, “Design and simulation of photonics bandgap switch”
41. Lian Yanru, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Turbo equalization based on genetic algorithms for
coded Iitersymbol interference channels”
42. Liang Soon Fong, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Crystalline soft-underlayer for high-density
perpendicular recording media”
43. Lim Kah Guan, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Analyzing the mechanism responses of a hard-disk drive
using multi-criteria decision methodologies”
44. Lim Wee Han Ronald, School of Materials Science and Engineering, College of Engineering,
Nanyang Technological University, “4th generation optica media”
45. Lim Xiuzheng, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “Data storage security in PC environment”
46. Lim Xu En, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Transparent mask fabrication for laser nano-imprinting”
RESEARCH COMMUNITY
47. Lin Hongbo, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Nano-metrology and instrumentation: Electronics
development”
48. Lin Jiahao Alvin, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Advanced signal processing for micro motor performance
diagnosis”
49. Lin Weijie, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Measurement of flow-induced vibration of hard disk drives”
50. Liu Huaqing, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Metal nanostructures for plasmonics”
51. Loh Guan Chee Jarvis, School of Electrical and Electronic Engineering, College of
Engineering, Nanyang Technological University, “Ultra high magnetic recording naterials”
52. Mou Junyuan Jack, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Modelling of ballistic spin transport”
53. Neo Chern Leng, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Characterisation of carbon nanostructured materials”
54. Ng Hui Ling, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Patterning of magnetic nano-structures”
55. Ng Keh Ying Mavis, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Solid substrate laser ablation in different
temperature environments”
56. Ng Seo Phei, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Ferroelectric property of ferroelectric thin film deposited via dual
laser beam deposition”
57. Nian Jialiang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Nano-metrology and instrumentation: Electronics
development”
111
112
RESEARCH COMMUNITY
students
58. Ong Jun Jie Alvin, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Characterization of perpendicular recording
media”
59. Pan Qi, Department of Electrical & Computer Engineering, Faculty of Engineering, National
University of Singapore, “Study of dispersion compensation device”
60. Peh Chester, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Iterative receivers for multiusers spacetime mimo
systems”
61. Phuah Kian Boon, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Measurement of nanosurface roughness and defects of hard disk”
62. Poh Wei Da, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Tip reconstruction for scanning probe microscope”
63. Prashant Sarkar, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Digital signal processing for holographic storage system”
64. Quek Xieyuan Andrew, School of Electrical and Electronic Engineering, College of
Engineering, Nanyang Technological University, “Thin film technology for magnetic read
heads used in Hard Disk Drive”
65. Reena Devi D/O Arjun Singh, School of Materials Science and Engineering, College of
Engineering, Nanyang Technological University, “Research on the matching of disk overcoat
with disk lubricant for magnetic disk”
66. Sathyan Menon, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Laser nano-imprinting to fabricate sub-micron and nanostructures”
67. Saw Wei Xiong, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Fabrication of ultra-shallow junctions by laser annealing”
RESEARCH COMMUNITY
68. Ser Guang Juin Kain, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “On the measurement of air gaps for laser
nanoimprinting”
69. Shaw Ray, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Design of regenerative power supply for self-contained
devices”
70. Sim Cheow Hin, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Growth and characterization of half-metallic Heusier
alloys”
71. Sim Heng Lip, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “High anisotropy FePt-Cu thin film for ultra-high density
recording”
72. Sim Lim Ai, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Theoretical modeling of plasmonic propagating”
73. Srikrishna Jagannathan, Department of Electrical & Computer Engineering, Faculty
of Engineering, National University of Singapore, “Transport properties in magnetic
semiconductors”
74. Syed Hafidz Khairuddin Bin Othman A, Department of Electrical & Computer Engineering,
Faculty of Engineering, National University of Singapore, “Enhancing the resolution of
magnetic force microscopy through modeling of the MFM tip”
75. Tan Chin Lee, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Thin film technology for magnetic read heads used in
hard disk drive”
76. Tan Chun Chia, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Investigation on advanced phase change random access
memory” ( Winner of Micron Innovation Award, 2nd in IEEE Region 10 student paper contest
2007 and Merit Award for 21st Faculty of Engineering Innovation and Research Award)
113
114
RESEARCH COMMUNITY
students
77. Tan Eu Jin, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “Reconfigurable accelerator for DSP algorithm verification”
78. Tan Fang Kwang, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Tip reconstruction for scanning probe microscope”
79. Tan Gui Xiang, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Investigation of heat flux relating to hard disk read/write
head”
80. Tan Sok Sang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Study of nano phase change on phase change random
access memory”
81. Tan Sze Teng, School of Materials Science and Engineering, College of Engineering,
Nanyang Technological University, “Shock response analysis and novel damper
development for SFF hard disk drives”
82. Tan Teck Beng, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Fabrication of carbon nanostructured materials: Studies
on the deposition of catalyst”
83. Tang Siwei, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “High repetition rate and ultra-short pulse laser
application in bio-imaging”
84. Tay Han Woon Alvin, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “128bits nano-PCRAM chip” (21st Faculty of
Engineering Innovation - Certificate of Recognition)
85. Tay Kathy, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Dynamic behaviour of magnetic head disk interface of
computer hard disk drive subjected to electrostatic force”
86. Teo Weizhi Michelle, School of Electrical and Electronic Engineering, College of
Engineering, Nanyang Technological University, “Message security study of data storage and
email system”
RESEARCH COMMUNITY
87. Thia Yew Kwan, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Nanoparticle tribology and damage evaluation on hard
disk drive”
88. Tia Siew Chern, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Investigations on perpendicular recording media”
89. Tian Yutian, School of Materials Science and Engineering, College of Engineering, Nanyang
Technological University, “Property study of phase change materials for optical media”
90. Toh Kwok Hoong Jerry, School of Materials Science and Engineering, College of
Engineering, Nanyang Technological University, “Ultra-thin overcoat for magnetic head of
computer hard disk drive”
91. Tung Sze Hwee, School of Materials Science and Engineering, College of Engineering,
Nanyang Technological University, “Patterning technology development using phase
change materials”
92. Wang Pinyi, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Modeling of current across magnetic multilayers”
93. Wee Ngai Shen , School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Stability analysis of air bearing system in micro/MEMS
devices”
94. Woo Yingming, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Material engineering of phase change random access
memory cells”
95. Wu Li Kevin, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “Data storage security in PC environment”
96. Wu Wei Meng Jason, School of Electrical and Electronic Engineering, College of
Engineering, Nanyang Technological University, “Controller and interface study in small form
factor drive”
115
116
RESEARCH COMMUNITY
students
97. Wu Zhantao, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Identification of “hit” signal for ultra-low glide height disks
in perpendicular recording media”
98. Yan Lin Aung , School of Computer Engineering, College of Engineering, Nanyang
Technological University, “Accelerating system performance using the APU controller and
FCMs”
99. Yang Fang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Spindle motor with FPGA implementation”
100. Yang Qi, School of Electrical and Electronic Engineering, College of Engineering, Nanyang
Technological University, “Lab-on-a- chip for biology cell sorting and detection”
101. Yeo Yixiong Ansley, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “Fast autofocus for automated microscopes”
102. Yip Kai Meng Ragner, School of Electrical and Electronic Engineering, College of
Engineering, Nanyang Technological University, “Controller and interface study in small form
factor drive”
103. Yong Ching Fatt, School of Mechanical and Aerospace Engineering, College of Engineering,
Nanyang Technological University, “Experimental and numerical studies of air bearing
sliders”
104. Zeng Liyan, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Security study of data storage in internet-PC
environment”
105. Zer Che Su Su Thwin, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Compensation of disk flutter disturbances in
hard disk drive servo through nonlinear reset-integrator”
106. Zhang Jian, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Nano-phase change and its application on phase
change random access memory”
RESEARCH COMMUNITY
107. Zheng Pengyuan, Department of Materials Science & Engineering, Faculty of Engineering,
National University of Singapore, “Curie Temperature and magnetic anisotropy of
nanostructured magnetic films”
108. Zhuang Yaoyang, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Fabrication of new materials for
perpendicular recording”
Industry Attachment/Internship – A*STAR BS-PhD Pre-Attachment
Programme
1.
Leong Zhidong, “Nanoscience research”
2.
Lee Silvanus, “Spintronics and nanotechnology”
Industry Attachment/Internship – A*STAR Summer Attachment
Programme
1.
Chee Ru-Ern, UC Berkeley, “Barrier interaction time in tunneling”
2.
Chua Huiyi Jay, UC Berkeley, “Barrier interaction time in tunneling”
3.
Leong Qixiang, UC Berkeley, “Thin film growth and characterisation for magnetic
nanostructures”
Industry Attachment/Internship – A*STAR Young Research Attachment
Programme
1.
Nguyen Manh Huy, NUS High School, “Post-processing and glide testing for magnetic
recording media of hard disk drive”
2.
Vuong Hoang Kim, NUS High School, “Post-processing and glide testing for magnetic
recording media of hard disk drive”
117
RESEARCH COMMUNITY
118
students
3.
Du Hai Ha, Methodist Girls’ School, “Visualization of heat”
4.
Nguyen Duc Chinh, National Junior College, “Visualization of heat”
5.
Nguyen Duy Tin, Raffles Institution, “Fe-based nanoparticles doped Cu/Zn nanowires”
6.
Nguyen Duy Tri, Raffles Institution, “Fe-based nanoparticles doped Cu/Zn nanowires”
7.
Nguyen Han Minh, National Junior College, “Visualization of heat”
8.
Tran Ba Khoi Nguyen, Saint Joseph’s Institution, “Visualization of heat”
Industry Attachment/Internship – A*STAR–MOE Student Attachment
Programme
1.
Abdul Hanif B Zaini, Meridian Junior College, “MEMS technology and applications”
2.
Darrel Ang Tzer Hong, Anderson Junior College, “Beam-shaped laser diode”
3.
Eugene Lau Yu Jun, Pioneer Junior College, “Beam-shaped laser diode”
4.
Lee Kuan Hui, Anglo-Chinese Junior College, “Technologies for 400-500 Gb/inch2 for
perpendicular magnetic Rrcording”
5.
Liang Yuanruo, Anglo Chinese School, “Technologies for 400-500 Gb/inch2 for
perpendicular magnetic recording”
6.
Caremelita Jade Ng, Tampines Junior College, “Hard disk drive servo systems”
7.
Catherine Ng Xiuwen, Anderson Junior College, “Analytical solutions of the Navier Stokes
equations representing steady rotationally symmetric flow”
8.
Merlisa Pung Yan Ron, Pioneer Junior College, “Analytical solutions of the Navier Stokes
9.
Ravinder Singh Yadav, St Andrew’s Junior College, “Analytical solutions of the Navier
Stokes equations representing steady rotationally symmetric flow”
RESEARCH COMMUNITY
10. Tammy Tan Yan Jun, Jurong Junior College, “Beam-shaped laser diode”
11. Teo Mei Ping, Anglo-Chinese Junior College, “Magnetic and electrical testing methods for
hard disk media”
12. Ian Yeo Enyong, Jurong Junior College, “Magnetic and electrical testing methods for hard
disk media”
13. Chia Rui Ming Daryl, Temasek Junior College, “Analytical solutions of the Navier Stokes
14. Gladia Chork Hotan, Temasek Junior College, “Analytical solutions of the Navier Stokes
15. Chen Liling, Temasek Junior College, “Analytical solutions of the Navier Stokes equations
representing steady rotationally symmetric flow”
Industry Attachment/Internship – Polytechnic
1.
Ajay Kumar Rai, Division of Electronic & Computer Engineering, School of Engineering,
Ngee Ann Polytechnic, “Development of a low-cost maskless photolithography system”
2.
Alwin Teo Jie Sheng, Division of Mechnical Engineering, School of Engineering, Ngee Ann
Polytechnic, “Flow induced vibrations on HDD actuator study”
3.
Ang Boon Qian, School of Electrical & Electronic Engineering, Singapore Polytechnic, “Built
in vision for laser precision microfabrication”
4.
Aung Kywa Zwa, Division of Electronic & Computer Engineering, School of Engineering,
Ngee Ann Polytechnic, “Nano-phase change and its application on phase change random
access memory”
5.
Chan Jiawei Marvin, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Applications in laser precision mircofabrication”
119
RESEARCH COMMUNITY
120
students
6.
Chan Shu-E Kimberly, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Investigation of hard disk media surface with different carbon overcoat layers”
7.
Chan Woei Lih, Division of Multidiscipline Engineering, School of Engineering, Ngee Ann
Polytechnic, “Signal processing of spin transfer noise in nanomagnets”
8.
Chang Yong Shen, School of Information Technology, Nanyang Polytechnic, “Development
of advanced metrology tool for surface inspection”
9.
Chew Jin Hong Daryl, School of InfoComm Technology, Ngee Ann Polytechnic, “Network
storage simulation”
10. Chua Hui Peng, Division of Multidiscipline Engineering, School of Engineering, Ngee Ann
Polytechnic, “Post-processing of hard disk for hard disk drive”
11. Dina Christiani Joewono, School of Engineering, Nanyang Polytechnic, “Simulation of short
range interaction in head-disk interface”
12. Gan Ka He, Division of Mechnical Engineering, School of Engineering, Ngee Ann
Polytechnic, “Flow Induced Vibrations in Hard Disk Drives”
13. Go Qing Hao, Division of Electronic & Computer Engineering, School of Engineering, Ngee
Ann Polytechnic, “Data storage security technology by using USB drive”
14. Goh Jun Teck, Division of Electronic & Computer Engineering, School of Engineering, Ngee
Ann Polytechnic, “Nano patterning process development”
15. Goh Xiang Fei, Division of Electronic & Computer Engineering, School of Engineering, Ngee
Ann Polytechnic, “Nano patterning process development”
16. Goh Ying Yi Alvin, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Investigation of corrosion sensor to determine micro-corrosion”
17. Han Myint Zaw, Division of Electronic & Computer Engineering, School of Engineering,
Ngee Ann Polytechnic, “Develop new E-beam nanopattern resist”
RESEARCH COMMUNITY
18. Heng Fuwen Victor, School of InfoComm Technology, Ngee Ann Polytechnic,
“Development of software modules for on-demand storage backup service over optical
network”
19. Khine Khant Nay Myo, Division of Electronic & Computer Engineering, School of
Engineering, Ngee Ann Polytechnic, “Develop new E-beam nanopattern resist”
20. Kuah Qiu Ling Dianne, School of InfoComm Technology, Ngee Ann Polytechnic, “Animation
of images for explaining data storage concepts”
21. Lee Seok Leng Christine, School of InfoComm Technology, Ngee Ann Polytechnic,
“Animation of images for explaining data storage concepts”
22. Lee Shu Xian, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Calculation of X1-P amount from Z-DOL and X1-P mixture lubricant”
23. Leo Yunn Leei, School of Mechanical & Manufacturing Engineering, Singapore Polytechnic,
“Applications of Laser Microprocessing”
24. Leong Siang Liang, Division of Electronic & Computer Engineering, School of Engineering,
Ngee Ann Polytechnic, “Fabrication and characterization of the nano-metallic lens”
25. Leong Yew Chee, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Post-processing and glide test of magnetic recording media for hard disk drive”
26. Li Geng Zhen, Division of Electronic & Computer Engineering, School of Engineering, Ngee
Ann Polytechnic, “Generation of Nano-sized light spot”
27. Li Xiang, Division of Electronic & Computer Engineering, School of Engineering, Ngee Ann
Polytechnic, “New E-beam resists for fine nanopatterns used in data storage”
28. Liew Jia Wei, Division of Multidiscipline Engineering, School of Engineering, Ngee Ann
Polytechnic, “Application of design of experiments in tape-burnish/wiping process of hard
disk in hard disk hrive”
29. Lim Kok Kiong Andrew, School of Engineering, Nanyang Polytechnic, “Applications of Laser
Micro-Processing”
121
122
RESEARCH COMMUNITY
students
30. Lim Sok Yum, Division of Electronic & Computer Engineering, School of Engineering, Ngee
Ann Polytechnic, “Nano fabrication process development and characterization”
31. Lin Fuchun, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Investigation of the lubricant effect on hard disk corrosion”
32. Low Jianwei Ian, School of Electrical & Electronic Engineering, Singapore Polytechnic, “Postprocessing and glide test of magnetic recording media for hard disk drive”
33. Muhammad Ridhwan Bin Sarkinin, School of Mechanical & Manufacturing Engineering,
Singapore Polytechnic, “Sputtering process in thin-film technology”
34. Nang Mo, School of Engineering, Nanyang Polytechnic, “Development of kernel modules
and application software for embedded linux system”
35. Neo Yi Ming, School of Engineering, Nanyang Polytechnic, “Development of advanced
metrology tool for surface inspection”
36. Ng Su Shan, School of Mechanical & Manufacturing Engineering, Singapore Polytechnic,
“Applications in laser precision mircofabrication”
37. Ng Wei Long, School of InfoComm Technology, Ngee Ann Polytechnic, “Storage based
Intrusion Detection for Network Storage”
38. Ng Wei Qiang Benjamin, Division of Mechnical Engineering, School of Engineering, Ngee
Ann Polytechnic, “Flow induced vibration in hard disk drives & other airflow related issue”
39. Ong Chuon Lian, Division of Mechnical Engineering, School of Engineering, Ngee Ann
Polytechnic, “Post-processing of hard disk for hard disk drive”
40. Pan Jing, Division of Electronic & Computer Engineering, School of Engineering, Ngee Ann
Polytechnic, “Nano-structure fabrication and characterization”
41. Peh Cai Yun, Division of Multidiscipline Engineering, School of Engineering, Ngee Ann
Polytechnic, “Application of design of experiments in tape-burnish/wiping process of hard
disk in hard disk drive”
RESEARCH COMMUNITY
42. Phang Jian Kai, Division of Electronic & Computer Engineering, School of Engineering,
Ngee Ann Polytechnic, “To achieve fine nanopatterns (< 50 nm) for ultra-high density read
heads”
43. Phone Zaw Phyo, Division of Mechnical Engineering, School of Engineering, Ngee Ann
Polytechnic, “Laser structuring on quartz substrates for photonic applications”
44. Quek Chin Kuan Davin, School of Mechanical & Manufacturing Engineering, Singapore
Polytechnic, “Applications of laser microprocessing”
45. Rabe’ah Bte Kamarudin, Division of Electronic & Computer Engineering, School of
Engineering, Ngee Ann Polytechnic, “Fabrication and characterisation of microlens Array”
46. Shezhiyan, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Applications in Laser Precision mircofabrication”
47. Shiau Li Lynn, Division of Mechnical Engineering, School of Engineering, Ngee Ann
Polytechnic, “Magnetic media performance characterization”
48. Soon Jiaqing Victor, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Built in vision (BIV) for laser precision microfabrication”
49. Tan Bingyi, Division of Electronic & Computer Engineering, School of Engineering, Ngee
Ann Polytechnic, “3D photonic crystal structure and its application in optical data storage”
50. Tan James, School of Electrical & Electronic Engineering, Singapore Polytechnic, “Study of
Z-DOL and X1-P hard disk media lubricant”
51. Tan Kah Yong, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Sputtering process in thin-film technology”
52. Tan Ming Fen Esther, Division of Multidiscipline Engineering, School of Engineering, Ngee
Ann Polytechnic, “DOE application in media post-processing”
53. Tan Wei Kiang, School of Electrical & Electronic Engineering, Singapore Polytechnic, “Hard
123
RESEARCH COMMUNITY
124
students
54. Tan Yan Qin, School of InfoComm Technology, Ngee Ann Polytechnic, “Network storage
simulation”
55. Wong Mun Wei, School of Electrical & Electronic Engineering, Singapore Polytechnic, “Hard
56. Wong Yoke Ying, School of Electrical & Electronic Engineering, Singapore Polytechnic, “Hard
57. Yang Bo, School of Electrical & Electronic Engineering, Singapore Polytechnic, “Corrosion
study of magnetic sliders”
58. Ye Aung, Division of Mechnical Engineering, School of Engineering, Ngee Ann Polytechnic,
“Nano-structure fabrication and characterization”
59. Yeoh Wei Ling Lena, Division of Electronic & Computer Engineering, School of Engineering,
Ngee Ann Polytechnic, “3D photonic crystal structure and its application in optical data
storage”
60. Yu Jie, Division of Mechnical Engineering, School of Engineering, Ngee Ann Polytechnic,
“Magnetic media performance characterization”
61. Zheng Qingyu, School of Electrical & Electronic Engineering, Singapore Polytechnic,
“Electronics design of experimental setup for Advanced intelligent control for hard disk
drive in mobile applications”
62. Zune Min Latt, Division of Electronic & Computer Engineering, School of Engineering, Ngee
Ann Polytechnic, “Nano-phase change and its application on phase change random access
memory”
Industry Attachment/Internship – University
1.
Aaron Hah Fei Lik, Department of Industrial & Systems Engineering, Faculty of Engineering,
National University of Singapore, “Application of DoE methods in media post-processing”
2.
Abd-Ur-Rehman Mustafa, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Automation development and control of
nano-instrumentation”
RESEARCH COMMUNITY
3.
Albert Tanudjaya, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Experimental study on contact induced vibration of
glide head”
4.
An Jia, School of Chemical and Biomedical Engineering, College of Engineering, Nanyang
Technological University, “Auto-focus microscope by laser inspection”
5.
Ang Ching Mei, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “System optimization for laser wet-etching of quartz for photonic
applications”
6.
Ang Wee Meng, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Material investigation for phase change random access
memory”
7.
Arpan Roy, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Optical design and testing”
8.
Auw Rui Xuan Maisie, School of Chemical and Biomedical Engineering, College
of Engineering, Nanyang Technological University, “Nano-structure fabrication and
characterization”
9.
Chan Chia Sern, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Electron beam lithography for the fabrication of
nanoscale MRAM”
10. Chen Junhao, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Design of HAMR servo and photodetector PCB board”
11. Chen Junxiong, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Data collection and analysis for storage security”
12. Chen Li Han , School of Chemical and Biomedical Engineering, College of Engineering,
Nanyang Technological University, “Experimental study and design of anti-bouncing headsuspension assembly for hard disk drives”
125
126
RESEARCH COMMUNITY
students
13. Cher Jingting, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Development of memory nanocell for high density
information storage”
14. Cher Kiat Min Kelvin, Department of Materials Science & Engineering, Faculty of
Engineering, National University of Singapore, “Extremely–high density perpendicular
recording media”
15. Choo Ban Hwa, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Study of heat transfer and thermal effect on HAMR head”
16. Chua Zin Yan, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “RTOS and FPGA-based RISC processor embedded system”
17. Du Weichao, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “SAN storage simulation for object-based storage device”
18. Eng Weijie, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “High performance phase change random access memory
cells”
19. Ho Jian Wei, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Identification of glide hit signal for hard disk drives”
20. Ho Jun Jie Terence, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Magnetic read Head for ultrohigh density recording”
21. Hu Nan, Department of Electrical & Computer Engineering, Faculty of Engineering, National
University of Singapore, “Thermal-imaging analysis”
22. Huang Lisen, Department of Materials Science & Engineering, Faculty of Engineering,
National University of Singapore, “Magnetic granular thin films for perpendicular recording”
23. Huang Yu Qian Jason, School of Chemical and Biomedical Engineering, College of
Engineering, Nanyang Technological University, “Built in vision for laser micromachining
- Mechanical and Optical Design”
RESEARCH COMMUNITY
24. Huang Yue, Department of Chemical Engineering, Faculty of Engineering, National
University of Singapore, “Investigation of corrosion sensor to determine micro-corrosion”
25. Jessica Henry, School of Materials Science and Engineering, College of Engineering,
Nanyang Technological University, “ICP etch and sputtering process development for read
sensor fabrication”
26. Ko Li Ling, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “User interface programming of the PCRAM cell design
software”
27. Koh Sek Lin Adelene, School of Chemical and Biomedical Engineering, College of
Engineering, Nanyang Technological University, “Bio-compatible magnetic nanoparticle”
28. Koh Yong Chuan, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Optimizing electrodeposition parameters to achieve
ultra-low Hc and ultra-high Bs CoFe Film”
29. Koppa Vijetha, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Development of software modules for on-demand
backup storage service over optical network”
30. Ku Wei Chiet, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “Wireless media storage system”
31. Kwek Joon Keng, School of Chemical and Biomedical Engineering, College of Engineering,
Nanyang Technological University, “Integrative research and development of nanoinstrumentation”
32. Lau Ching Man, School of Materials Science and Engineering, College of Engineering,
Nanyang Technological University, “Lithography Process development for nanoscale
magnetic sensor fabrication”
33. Lau Koon Tuck Vincent, School of Materials Science and Engineering, College of
Engineering, Nanyang Technological University, “Development of E-book”
127
128
RESEARCH COMMUNITY
students
34. Law Heng Kai Felix, Department of Materials Science & Engineering, Faculty of
Engineering, National University of Singapore, “Extremely–high density perpendicular
recording media”
35. Lee Yixian, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Tiny area thermal-imaging analysis”
36. Ler Guang Qin Jasper, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “System optimization for laser wet-etching of
quartz for photonic applications”
37. Li Bingrui Joel, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Fabrication of optical waveguide for HAMR optical head”
38. Li Bingxuan, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Distributed RAID iSCSI initiator”
39. Li Ming, School of Electrical and Electronic Engineering, College of Engineering, Nanyang
Technological University, “Laser synthesis of new phase change materials”
40. Liang Jieyong, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Fabrication of magnetic random access memory device”
41. Lin Hongbo, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Data acquisition and software development for media
characterization”
42. Liu Sisi, Department of Materials Science & Engineering, Faculty of Engineering, National
University of Singapore, “An investigation for heat transfer in nano-wires”
43. Loke Kok Leong Desmond, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Development of memory nanocell for high
density information storage”
44. Lua Yali Angela, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Mechanical design for laser diode module”
RESEARCH COMMUNITY
45. Lydia Makmur, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Head disk interface technology for 2.5nm flying height”
46. Malavika Rewari, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Material investigation for phase change
47. Nah Wenbin, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Head disk interface technology for 2.5nm flying height”
48. Ng Han Leong, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Development of memory nanocell for high density
information storage”
49. Ng Keh Ying Mavis, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Hybrid assisted laser precision engineering”
50. Ng Kian Chee Alan, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Storage based Intrusion detection for
network storage”
51. Ng Yihang, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “The length scale problem in disk drive flows”
52. Norlizawati Binte Juahil, School of Chemical and Biomedical Engineering, College of
Engineering, Nanyang Technological University, “Numerical simulation and experimental
study of air bearing sliders”
53. Pan Xiaoshu, Department of Industrial & Systems Engineering, Faculty of Engineering,
National University of Singapore, “Post-processing and glide testing of magnetic recording
media for hard disk drive”
54. Phan Buu Minh, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Modification of a versatile of a 3-D laser scanning
microscopic imaging system”
129
130
RESEARCH COMMUNITY
students
55. Phyu Phyu Tin, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Data acquisition and software development for
magnetic disk performance characterization”
56. Rezuan Bin Kassim, School of Chemical and Biomedical Engineering, College of
Engineering, Nanyang Technological University, “Integrative research and development of
nano-instrumentation”
57. Sathyan Menon, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Applications of laser microprocessing”
58. Song Wei Li, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “PCRAM measurement PCB board and IC socket design”
59. Sylvia Rizkinta Tarigan, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “Development of software modules for on-demand backup
storage service over optical network”
60. Tan Kang Hao, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Modification and integration of laser modulation and
power supply circuits into an independent unit”
61. Tan Pei Xin Nikki, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Design and fabrication of mechanical fixtures”
62. Tan Sok Sang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Material investigation for phase change random access
memory”
63. Tan Wing Hoe, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Automation development and control of nano-instrumentation”
64. Tan Woei Ming, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Exploration and refinement of the versatile nano
resolution 3-D imaging system”
RESEARCH COMMUNITY
65. Tan Zhi Xuan, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Design and assembly of electronic circuit setup”
66. Tao Shanjun, Department of Electrical & Computer Engineering, Faculty of Engineering,
67. Tay Han Woon Alvin, Department of Electrical & Computer Engineering, Faculty of
68. Teo Chang Sheng, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Embedded system testing and firmware
development on portable devices”
69. Teo Cheng Tat Frederick, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Distributed RAID iSCSI initiator”
70. Toh Freddy, Department of Mechanical Engineering, Faculty of Engineering, National
University of Singapore, “Applications of laser microprocessing”
71. Toh Minglin, School of Chemical and Biomedical Engineering, College of Engineering,
Nanyang Technological University, “Computer aided structure design of PCRAM cells”
72. Toh Yinghui, School of Chemical and Biomedical Engineering, College of Engineering,
Nanyang Technological University, “Surface plasmons components and potential
applications”
73. Truong Minh Nhat, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “FPGA-based RISC processor embedded system”
74. Vu Quang Vinh, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “ICP etch and sputtering process development for read
sensor fabrication”
75. Wang Li, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Investigation of hard disk media and heads corrosion in
the operating system”
131
132
RESEARCH COMMUNITY
students
76. Wang Wei, Department of Electrical & Computer Engineering, Faculty of Engineering,
77. Wong Wei Yang Brian, School of Electrical and Electronic Engineering, College of
Engineering, Nanyang Technological University, “Fabrication of ultra-soft & high Bs FeCo(Ni)
Nano-/Micro-films via electrodeposition-characterization & analysis of FeCo(Ni) films”
78. Woo Choon Hoong, Department of Electrical & Computer Engineering, Faculty of
Engineering, National University of Singapore, “Study of heat transfer and thermal effect on
HAMR head”
79. Woo Yingming, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “High performance phase change random access memory
cells”
80. Wu Zhantao, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Analysis and processing of glide hit signal for hard disk
drives”
81. Xia Shuangjun, Department of Industrial & Systems Engineering, Faculty of Engineering,
National University of Singapore, “User interface programming of the PCRAM cell design
software”
82. Xia Yang, School of Computer Engineering, College of Engineering, Nanyang Technological
University, “Development of software modules for on-demand backup storage service over
optical network”
83. Xiao Li, Department of Electrical & Computer Engineering, Faculty of Engineering, National
University of Singapore, “Development of MEMS XY-Stage for probe data storage”
84. Xiao Lizhi, School of Electrical and Electronic Engineering, College of Engineering, Nanyang
85. Xue Xiang, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Optical constants database creation and testing & fitting
for thin film materials”
RESEARCH COMMUNITY
86. Yan Lin Aung, School of Computer Engineering, College of Engineering, Nanyang
87. Yang Geng, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “System optimization for laser wet-etching of quartz for
photonic applications”
88. Yi Jinzhou, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Fabrication of optical waveguide for HAMR optical head”
89. Zhang Guofan, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “Characterization of optical waveguide for HAMR optical
head”
90. Zhang Kuan, School of Computer Engineering, College of Engineering, Nanyang
Technological University, “Kernel module and block device driver development”
91. Zhang Xue Yi, School of Electrical and Electronic Engineering, College of Engineering,
Nanyang Technological University, “Autofocus microscope by laser inspection”
92. Zhang Yifeng, Department of Electrical & Computer Engineering, Faculty of Engineering,
National University of Singapore, “C programming for Texas Instrument microcontroller”
93. Zheng Qingxiang, Department of Electrical & Computer Engineering, Faculty of
94. Zhong Wenxin, School of Chemical and Biomedical Engineering, College of Engineering,
Nanyang Technological University, “Thermal property study of laser heating storage
material”
95. Zhou Zhengzhong, Department of Chemical Engineering, Faculty of Engineering, National
University of Singapore, “Fabrication of ultra-soft & High Bs FeCo(Ni) Nano-/Micro-films via
electrodeposition-optimization of electroplating parameters & additives”
133
134
RESEARCH COMMUNITY
RESEARCH COMMUNITY
visiting professors
We remain
connected to
the research
community
by inviting
distinguished
scientists on a
regular basis.
Proactive
interaction
has facilitated
the exchange
of research
ideas. These
interactions have
also significantly
strengthen ties
between our
researchers and our
visiting scientists.
9 - 16 March 07
Prof Ho Seng Tiong
Professor of Electronical and
Computer Engineering at
Northwestern University, USA
14 August - 11 September 06
Prof Frank L. Lewis
Associate Director for Research,
Automation & Robotics Research
Institute, University of Texas at
Arlington, USA
15 December 06 - 6 February 07
Prof Kees A. Schouhamer Immink
President and founder of Turing
Machines Inc. & Adjunct Professor
at the Institute for
Experimental Mathematics,
University of Essen, Germany
24 July - 1 September 06
Prof Peter George
Professor of Electrical &
Computer Engineering,
Saint Cloud State University,
Saint Cloud, Minnesota
21 - 27 November 06
Dr Hsia Yiao Tee
Director, Mechanical Integration &
Tribology Research Group,
Seagate Technology
Research Center
19 June - 11 July 06
Dr Alekandar Kavcic
Associate Professor, Engineering
& Applied Science,
Harvard University, USA
20 - 24 November 06 /
28 August - 1 September 06
Prof Gen Tatara
Associate Professor, Tokyo
Metropolitan University,
Department of Physics,
Graduate School of Science
31 March - 6 May 2006
Dr Emad Azmy Sultan Girgis
Institute For Thin Film and
Ion Technology, Germany
18 - 20 October 06
Prof Kemal Hanjalic
Professor and Head of
Thermofluids section,
Faculty of Applied Sciences,
Delft University of Technology
27 March - 26 September 06
Prof Andrey Trofimov
Associate professor, Information
Systems Department,
St.Petersburg State University
of Aerospace Instrumentation
(SUAI), Russia
18 - 20 September 06
Prof Jimmy Zhu
Director at Data Storage
Systems Center and Professor
of Electrical and
Computer Engineering at
Carnegie Mellon University
RESEARCH COMMUNITY
RESEARCH COMMUNITY
Our university
bilateral linkages
remain strong
with DSI’s staff
holding adjunct
positions with the
National University
of Singapore and
the Nanyang
Technological
University. DSI also
actively engage
faculty members
and associates to
work with our staff
on joint projects and
initiatives.
NATIONAL UNIVERSITY OF SINGAPORE
Prof Ong Chong Kim, Physics Department
A/Prof A Al-Mamun, Electrical and Computer Engineering Department
A/Prof Cheng Hon Huan, Physics Department
A/Prof Chow Gan Moog, Materials Science and Engineering Department
A/ Prof Ding Jun, Materials Science and Engineering Department
A/Prof Feng Yuan Ping, Physics Department
A/Prof Ge Shuzhi, Sam, Electrical and Computer Engineering Department
A/ Prof Li Lewei, Electrical and Computer Engineering Department
A/Prof Lim Siak Piang, Mechanical Engineering Department
A/Prof Lu Li, Mechanical Engineering Department
A/Prof Shen Zexiang, Physics Department
A/ Prof Wu Yihong, Electrical and Computer Engineering Department
A/Prof Xiang Yang Liu, Physics Department
A/Prof Xu Yong Ping, Electrical and Computer Engineering Department
A/Prof Yi Li, Materials Science and Engineering Department
Dr Adekunle Olusola Adeyeye, Electrical and Computer Engineering Department
Dr George Mathew, Electrical and Computer Engineering Department
Dr Hao Gong, Materials Science and Engineering Department
Dr Mansoor Bin Abdul Jalil, Electrical and Computer Engineering Department
Dr Teo Kie Leong, Electrical and Computer Engineering Department
Dr Vivian Ng, Electrical and Computer Engineering Department
NANYANG TECHNOLOGICAL UNIVERSITY
Prof Ling Shih-Fu, Mechanical and Production Engineering
A/ Prof Du Hejun, Mechanical and Production Engineering
A/ Prof Yap Fook Fah, School of Mechanical and Aerospace Engineering
A/ Prof Huang Xiaoyang, Mechanical and Aerospace Engineering
A/ Prof Liu Erjia, Mechanical and Production Engineering
A/Prof Wang Shao, School of Mechanical and Aerospace Engineering
A/ Prof Tso Chingping, Mechanical and Production Engineering
A/Prof Wang Youyi, Electrical and Electronic Engineering
Prof Xie Lihua, School of Electrical and Electronic Engineering
OVERSEAS UNIVERSITY
Dr Matthew C. Turner, Engineering, University of Leicester, UK
Prof Frank L. Lewis, University of Texas at Arlington, USA
135
organisation chart
136
ORGANISATION CHART
management team
We believe that
a flat hierarchy
enables DSI in
retaining flexibility
and adaptability
to changes in
the needs of the
industry and to
technological
trends.
Executive Director
Prof Chong Tow Chong
Research
Industry Development
Administration
Dr Chang Kuan Teck
Deputy Director
(Industry)
Chrystine Woon
Deputy Director
Spintronics, Media, &
Interface
Business Development
Corporate Services
Dr Liu Bo
Dr Yeo You Huan
Tan Cheng Ann
Chrystine Woon
Pang Shoo Hoon
Mechatronics &
Recording Channel
Technology
Management
Tang Sweet Kook
Dr Liew Yun Fook
Deputy Director (Research)
Dr Ong Eng Hong
Zhang Jingliang
Optical Materials &
Systems
Dr Shi Luping
Network Storage
Technology
Dr Wang Yonghong
Teo Meng Thiam Willam
Integrative Science &
Engineering
Dr Liew Yun Fook
Dr Chang Kuan Teck
Director’s Office
Prof Chong Tow Chong
Executive Director
Dr Liew Yun Fook
Deputy Director (Research)
Finance
Human Resource
Reeco Cha
Network Computing
Systems, Services and
Support
Jason Yong
Facilities
William Ng
Chong Joon Fatt
Office of Graduate
Student Affairs
Soh Swee Hock
location map
VISION
To be a vital node in global
generation and innovation,
nurturing research talents and
capabilities for world class R&D in
next generation technologies.
MISSION
To establish Singapore as an
R&D centre of excellence in data
storage technologies.
Data Storage
Institute (DSI)
is conveniently
located within
the campus of the
National University
of Singapore (NUS)
at Engineering
Drive 1. It is
situated in the
vicinity of the Yusof
Ishak Hall, Raffles
Hall and Faculty of
Engineering
Wing 2.
DATA
STORAGE
INSTITUTE
DATA STORAGE INSTITUTE
DSI BUILDING
5 ENGINEERING DRIVE 1 (OFF KENT RIDGE CRESCENT, NUS)
SINGAPORE 117608
TEL: (65) 6874 6600
FAX: (65) 6776 6527
A N N UA L
06/07
DATA STORAGE INSTITUTE ANNUAL REPORT 06/07
w w w. d s i . a - st a r. e du.sg
R E P O RT

DSI Journal 2006

Transcription

Similar documents

waiver guidelines jakarta incident

HIKVISION ARG-77xxseries

UNIVERSAL LASER BORE SIGHTER–DELUXE KIT

South Asians - Institute of South Asian Studies

Dr. Daniel Y. Fung Dermal Laser Centre Yaletown, West Vancouver

4:00pm - Ultrazone

TGS_ADTS_CENTURION_v2:Layout 1.qxd

Resolution help from the experts

22 to .50 caliber laser bore sighter .22 to .50 caliber laser bore sighter

Synthesis, structural, magnetic and ferroelectric characterization of