Summer, 2011

Date of Issue: July 15, 2011

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Published by International Superconductivity Technology Center
1-10-13 Shinonome Koto-ku, Tokyo 135-0062, Japan Tel:+81-3-3536-7283, Fax:+81-3-3536-7318

Contents:
Topics- What’s New in the World of Superconductivity (April & May, 2011)
Feature Article: Advancements in Superconducting Industrial Equipment Technology- Trends in Superconducting Industrial Equipment Technology- Advancements in Superconducting Magnetic Separation Systems- Development of Seismic Isolation Systems based on Superconducting Magnetic Levitation- Development of High-Temperature Superconducting (HTS) Bulk Actuator- Development of Conveyor System utilizing Superconducting Magnetic Levitation- Advancements in Superconducting Motor Technology for Ship Propulsion- Development of High Temperature Superconductor Induction/Synchronous Machine (HTS-ISM)
for Transportation Equipment Applications- Magnetic Billet Heater
Feature Article: Advancements in Superconducting Wires/Tapes Technology- REBCO Coated Conductors- Performance Enhancements of Bi-based Superconducting Wires- Process Advancements in MgB2 Wire Technology- Advancement of Iron-based Superconducting Materials

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Top of Superconductivity Web21: http://www.istec.or.jp/web21/web21-E.html
This work was subsidized by the Japan Keirin Association using
promotion funds from KEIRIN RACE
http://ringring-keirin.jp

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Date of Issue: July 15, 2011

Superconductivity Web21
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Tel: +81-3-3536-7283, Fax: +81-3-3536-7318

What’s New in the World of Superconductivity (April & May)
Akihiko Tsutai, Director
International Affairs Division, ISTECAwardSuperconductor Technologies Inc. (May 12, 2011)
Superconductor Technologies Inc. (STI) has received the MICO award in recognition of its potentiallydisruptive and market-changing intellectual property (IP). The MICO award was presented by MDB CapitalGroup at the second annual Bright Lights Conference in New York City. The Bright Lights conference
focuses on publicly traded companies with disruptive and market-changing IP, providing institutional
investors with the opportunity to discover companies with embedded IP values that have been l argely
unrecognized. Jeff Quiram, STI's president and chief executive officer, commented, “We are leveraging our
extensive IP portfolio and manufacturing expertise to develop second generation (2G) HTS wire for large
emerging power generation device and electricity distribution markets. We are honored to receive the MICO
award, which recognizes our significant IP portfolio and the progress we have made applying our industry
leading expertise in HTS materials and manufacturing for existing applications that include high powertransmission cables, superconducting fault current limiters, and superconducting motors and generators."
Source:“STI Received MICO Award at MDB Capitals Bright Lights Conference 2011”
Superconductor Technologies Inc. press release (May 12, 2011)
http://phx.corporate-ir.net/phoenix.zhtml?c=70847&p=irol-newsArticle&ID=1562955&highlightPower
Converteam (April 4, 2011)
Converteam presented a w ide range of products and s ervices at the Hanover Fair in Germany.
Included in this presentation was the Hydrogenie project. With financing from the European Union,
Converteam is developing and building the first HTS generator to operate with practically no losses in ahydroelectric plant. The generator is scheduled to begin operation in Germany later this year. The HTS
generator promises a quant um leap in efficiency as w ell as space and w eight savings of up t o 70 %,compared with conventional solutions. The new technology for hydroelectric power plants represents anincreasingly profitable, environmentally friendly source of power generation.
Source:“Converteam at the Hanover Fair – with environmentally-friendly drive solutions”
Converteam press release (April 4, 2011)
http://www.converteam.com/majic/pageServer/100400019a0000/en/20110404-2-HanoverFair-eco-friendlysol.html

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Summer, 2011

Date of Issue: July 15, 2011

Superconductivity Web21
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American Superconductor Corporation (April 5, 2011)
American Superconductor Corporation (AMSC) has i ssued an updat e regarding its anticipatedfinancial results for its fourth quarter and f iscal year ending March 31, 2011. The update was issued in
response to the refusal of Sinovel Wind Group Co., Ltd. to accept contracted shipments of 1.5-MW and
3-MW wind turbine core electrical components that AMSC was prepared to deliver. These delayed
shipments are the primary cause for the lower-than-anticipated financial results for AMSC’s fourth quarterand full-year fiscal 2010. AMSC now expects that its total revenues for the fourth quarter will be less than
US $42 million and that it will generate a net loss for the fourth quarter on both a GAAP and non-GAAP
basis. Consequently, AMSC’s full-year fiscal 2010 revenues are now expected to be less than $355 million,
compared with the previous forecast of $430 million – 440 million. AMSC’s cash balance was also
negatively impacted by its increased inventory level relate to the refusal of shipments by SInovel andSinovel’s failure to pay AMSC for some contracted shipments made in fiscal year 2010. Such events havealso caused AMSC to review the appropriateness of the timing of its revenue recognition on approximately$56 million in unpaid shipments made during the second, third, and fourth quarters of fiscal 2010. AMSC iscontinuing to have active discussions with Sinovel regarding when Sinovel will accept further shipments andwhen it will be able to pay for past shipments.
Source:“AMSC Issues Update Regarding its Anticipated Fourth Quarter and Fiscal Year 2010 Financial Results”
American Superconductor Corporation press release (April 5, 2010)
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=1547039&highlight
Zenergy Power plc (April 5, 2011)
Zenergy Power plc has received an order from Applied Superconductor Ltd. for an engineering study
to create a detailed design and t o model the network impact of a s aturated-core superconducting fault
current limiter (SFCL) for the 33-kV distribution grid in the United Kingdom. Applied Superconductor, in turn,
received an or der for a 33 -kV FCL from CE Electric UK under the Low Carbon Network Fund Tier 1
arrangement. Herbert Piereder, CEO of Applied Superconductor, commented, “We believe that strategicallyplaced SFCLs will facilitate the connection of both renewable and non r enewable distributed generation.
They help the electricity network to withstand the consequential increase in fault level without the need for
major network reinforcements. We are currently looking at larger scale applications which will lead to
improved security and quality of electrical supply at affordable price levels.”
Source:“Order for Design and Engineering of 33-kV FCL”
Zenergy Power plc press release (April 5, 2011)
http://www.zenergypower.com/images/press_releases/2011/2011-04-05-order-for-design%20and-engineeri
ng-of-33-kV-fcl.pdf
Superconductor Technologies Inc. (April 6, 2011)
Superconductor Technologies Inc. (STI) has announced that Southwire Company has completed
the testing of STI’s second-generation HTS wire samples, confirming that the samples met the company’s
initial requirements for HTS AC power cable applications. The Los Alamos National Lab also performed thesame measurements on the same wire samples and obtained matching results. Jeff Quiram, STI's
president and chief executive officer, commented, "STI's pioneering work using RCE-CDR to make HTS
wire is promising an effective low-cost alternative to current manufacturing processes for HTS wire.
Southwire's validation demonstrates that our world-class 2G HTS wire technology is on track to enable
innovative AC power applications. We are eager to continue our work with Southwire in these exciting

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Date of Issue: July 15, 2011

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programs and we look forward to developing a business relationship for that purpose."
Source: “Superconductor Technologies Inc. Meets 2G HTS Wire Customer Requirements for HTS AC Power
Cable Applications”
Superconductor Technologies Inc. press release (April 6, 2011)
http://phx.corporate-ir.net/phoenix.zhtml?c=70847&p=irol-newsArticle&ID=1547158&highlight
Zenergy Power plc (April 13, April 14, and May 24, 2011)
On February 11, 2011, the Board of Zenergy Power announced the completion of a review of theGroup’s business and strategic options and an assessment of the long-term viability of the Group’s overall
strategy. At that time, the Group concluded that Zenergy’s business could best be developed as part of alarger group possessing access to funding and the necessary commercial relationships. Accordingly, theBoard began the process of seeking a purchaser for the group. Subsequently, the Board was advised byrepresentatives of certain shareholders that these shareholders do not believe that selling the company
would be in their best interests and that if the Board were to continue pursuing the sale of the company, therepresentatives would put forward a resolution to remove the non-executive Directors (NEDs) from theBoard. After consideration, the NEDs concluded that in view of the level of support, it would not be in thebest interests of the Company and shareholders to enter into a public debate regarding the Company’s
strategy. Consequently, the Board has resolved to terminate the sale process. The NEDs have also
resigned from the board, and a new Executive Chairman, Simon Cleaver, and two new non-executive
Directors, David Whelan and Georg Oehm, have joined the Board.
Regarding Zenergy’s new business strategy, the new Executive Chairman Simon Cleaver
commented, “The changed Board firmly believes that to have sold the Company in its entirety at the current
time would not have maximized the potential value of Zenergy. High Temperature Superconductivity (HTS)
has the ability to provide a step change in efficiency levels for electronic power distribution networks (grids),
electrical metal heating and renewable power generation and Zenergy is almost certainly the global leader
in the field. Whilst we need to get our sleeves rolled up and conduct an immediate review of the Company
before we issue any detailed plans, our initial strategy is based on using the Company’s specialist IP andknowledge to form joint ventures and strategic alliances to help commercialize Zenergy’s products. We arepleased to have concluded these Board changes. The Board will now be focused on giving the business a
new and very clear strategic direction with the aim of restoring shareholder value and working with industry
partners to continue developing what the Board believes is a suite of market leading products.”
In a subsequent statement made at the company’s Annual General Meeting on May 24, 2011, Mr.
Cleaver elaborated, “The previous board’s decision to put the Company into an ‘Offer Period’, which has
now ended, and announce that the Company was for sale, both surprised and disappointed me. I havealways believed that the intellectual property and technologies developed by Zenergy are both significant
and valuable and, was therefore concerned that this approach was unlikely to maximize the value of theCompany. Both David Whelan and D r Georg Oehm who recently joined the Board and who represent
parties with significant interests in Zenergy, together with a subst antial number of other shareholders,
agreed with this assessment. We did not take this action lightly. We were aware of the limited time horizon
in which to enact a turnaround. We simply believed, and still do, that Zenergy Power is one of the leading
exponents of High Temperature Superconductivity in the world and that this valuable intellectual property
was at risk of being sold as a distressed asset.”
After a review of the business, the new Board has found that the cash and burn rates are aspreviously stated and with the exception of a few well-documented and previously announced delays, nofundamental problems or technical issues exist. Technology development is progressing, although further
time is needed to fully develop and commercialize these products. A cost base review to identify areas

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Date of Issue: July 15, 2011

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where savings may be possible is presently ongoing. Regarding the company’s commercialization strategy,
Mr. Cleaver commented, “To achieve full commercialization we need bot h commercial and strategic
partners. This is not a new observation, as the Company has always needed partners. Our products indevelopment are products for the global marketplace. Zenergy lacks the infrastructure and reach to sell andmaintain these products on a gl obal scale. We are encouraged by the strong level of interest we havereceived from numerous significant industrial companies in developing a relationship with Zenergy. Whilst
the process is at an early stage, we are engaging with these parties to determine levels and areas ofinterest.”
Source:“Change of Directorate, End of offer period”
Zenergy Power plc press release (April 13, 2011)
http://www.zenergypower.com/images/press_releases/2011/2011-04-13-directorate-change-and-end-of-off
er-period.pdf“New Directors & Strategy Update”
Zenergy Power plc press release (April 14, 2011)
http://www.zenergypower.com/images/press_releases/2011/2011-04-14-new-directors-and-strategy-update.pdf“AGM Statement”
Zenergy Power plc press release (May 24, 2011)
http://www.zenergypower.com/images/press_releases/2011/2011-05-24-agm-statement.pdf
Nexans (April 15, 2011)
Nexans and 13 European partners have reached a significant milestone in the progression of the
EC-funded ECCOFLOW project to develop an innovative and multi-purpose superconducting fault current
limiter (SFCL) suitable for a variety of utility applications. The group announced that the design anddevelopment phase of the four-year project has now been completed and that the manufacturing of the
SFCL will soon begin. The ECCOFLOW SFCL will be assembled at Nexans’ facility in Germany and will be
installed at an Endesa substation in Palma de Mallorca, Spain, for testing. The device will use
second-generation HTS tapes for the current limiting components and represents the first multi-purpose unit
suitable for applications at different locations in the European grid. Once testing in Mallorca has been
completed, a long-term test in the Vychodoslovenska Energetika a.s. power network in Košice (Slovakia)
will begin. The ECCOFLOW project is being coordinated by Nexans and involves partners from throughout
the European Union, including several electric utilities.
Source:“Nexans coordinates the ECCOFLOW project for superconducting fault current limiter (SFCL) with new
generation tapes”
Nexans press release (April 15, 2011)
http://www.nexans.com/eservice/Corporate-en/navigatepub_142482_-30414/Nexans_coordinates_the_EC
COFLOW_project_for_superc.html
American Superconductor Corporation (April 21, 2011)
American Superconductor Corporation (AMSC) has announced that its HTS wire is being used in anelectrical substation built by the Institute of Electrical Engineering, China Academy of Science (IEE CAS) in
Baiyin, China. The IEE CAS is a scientific research base focused on the high-tech research anddevelopment of new electrical engineering and energy technologies. Dr. Xiao Liye, head of the IEE CAS,
commented, “The Baiyin superconductor substation is one of the most ambitious superconductor projects

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Date of Issue: July 15, 2011

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undertaken to date anywhere in the world. This is a holistic project that demonstrates how superconductors
will be applied in substations throughout China in the years ahead. As China's electricity needs continue toincrease, these solutions will be essential to maintain a high level of efficiency and reliability for our homes
and businesses.” The substation began oper ation in February 2011 and i ncludes all of the following
systems utilizing AMSC’s HTS wire: a superconductor fault current limiter, a superconductor power cablesystem, a superconductor magnetic energy storage (SMES) system, and a s uperconductor transformer.
Greg Yurek, American Superconductor founder and Chief Executive Officer, commented, “China is moving
forward on multiple fronts to become a first large-scale, commercial adopter of superconductor power grid
solutions. We applaud IEE CAS for developing superconductor products and implementing them in the
Baiyin substation, and we look forward to supporting many more such implementations in China in theyears ahead."
Source:“American Superconductor Wire Serves in Superconductor Electrical Substation in China”
American Superconductor Corporation press release (April 21, 2010)
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=1553151&highlight
Superconductor Technologies Inc. (May 4, 2011)
Superconductor Technologies Inc. (STI) reported its financial results for its first fiscal quarter, ending
April 2, 2011. The company’s total net revenues amounted to US $1.6 million, compared with $3.4 million forthe same quarter in the previous fiscal year. The net loss for the quarter was $3.7 million, compared with
$2.5 million for the same quarter in the previous year. Jeff Quiram, president and chief executive officer of
STI, reported that significant progress had been m ade in the company’s second-generation HTS wire
initiative during the first quarter: “In early February, we produced and delivered wire samples for all three of
our target applications: HTS wind turbines, HTS power cables and superconducting fault current limiters(SFCL). Our wire samples have now been tested and validated by three entities: Southwire Company, one
of North America's largest wire and c able providers; Los Alamos National Laboratory; and an i ndustry
leading manufacturer of large turbines and motors. Having demonstrated that our proprietary HTS
manufacturing process is capable of producing wire that meets customer specifications, our next objective isto establish commercial relationships with customers that will incorporate STI wire into new HTS devices.
We are also on track with our plans to adapt our manufacturing process to produce 2G HTS wire in thelonger lengths required by our customers.” As of April 2, 2011, STI had $16.1 million in cash and cash
equivalents. During the quarter, the company received $12.4 million in net proceeds from a registered direct
offering of common stock. At the end of the quarter, STI had a backlog of $72,000, compared with $724,000
at the end of the same quarter in the previous fiscal year.
Source:“Superconductor Technologies Reports First Quarter 2011 Results”
Superconductor Technologies Inc. press release (May 4, 2011)
http://phx.corporate-ir.net/phoenix.zhtml?c=70847&p=irol-newsArticle&ID=1559144&highlight
IOP Publishing (May 15, 2011)
In its journal Superconductor Science and Technology, IOP Publishing has pu blished a s tudy inwhich researchers examining Bi2212 reported that the capabilities of this material are limited by theformation of bubbles during the fabrication process. Bi2212 is presently the only high-temperature
superconductor that can be fabricated into a flexible round wire for use in magnet construction. For magnet
applications, the wires must exhibit a high critical current density that can be sustained in the presence oflarge magnetic fields. Previous studies have shown that the critical current varies markedly according to theSummer, 2011

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wire length, leading researchers at the Applied Superconductivity Center and the National High Magnetic
Field Laboratory at Florida State University to conclude that this variability may be caused by theconnectivity of Bi2212 grains within the wires. Bi2212 wires are fabricated using the powder-in-tube (PIT)
method. To clarify the processes occurring between the critical melt and re-growth steps in this process, theresearchers rapidly cooled wire samples at different times during the melting process. Using scanningelectron microscopy and synchrotron X-ray microtomography, the researchers observed that the small
powder pores that are inherent to the PIT process agglomerate into large bubbles upon entering the melting
stage. This process results in the division of the Bi2212 filaments into discrete segments with excellent
connectivity that are blocked by the residual bubbles, impairing the long-range filament connectivity andsuppressing current flow. The results suggest that a key approach to improving the critical current density ofthis material may be t o make the material denser prior to the melting stage. Various means ofaccomplishing this densification process are now being examined.
Source:“Bubble formation with filaments of melt processed Bi2212 wires and its strongly negative effect on the critical current
density" (Superconductor Science & Technology 24 075009)
http://iopscience.iop.org/0953-2048/24/7/075009
http://www.iop.org/news/11/may/page_50926.html
American Superconductor Corporation (May 24, 2011)
American Superconductor Corporation (AMSC) has announced that Daniel P. McGahn, President
and Chief Operating Officer, has been appoi nted Chief Executive Officer and a m ember of the Board of
Directors, effective June 1, 2011. Mr. McGahn will succeed Gregory J. Yurek, who is retiring after founding
AMSC and serving the company for more than two decades. Dr. Yurek will continue to serve as Chairmanof the Board until AMSC’s annual meeting of stockholders in August and as a S enior Advisor to thecompany for the next two years. Dr. Yurek commented, "The past 24 years have been challenging,exhilarating and rewarding. Together with a gr eat team at AMSC, we have been a super conductor
technology pioneer and evolved into a dynamic power technologies company. Having worked with Dan fornearly five years, I am confident in his ability to lead the company through today's obstacles and i nto
another era of growth." Regarding the succession, John Vander Sande, Lead Director of AMSC's Board of
Directors, commented, “Dan has impressed all of us in his time at AMSC. He is the ideal person to lead
AMSC forward upon Greg's retirement. The Board has the utmost confidence in Dan's ability to achieve a
new level of success by accelerating AMSC's business diversification. We are indebted to Greg for thesignificant contributions he has made to AMSC during the past 24 years and are pleased that he has
agreed to serve as a Senior Advisor to smooth the transition process.”
Source:“AMSC Announces CEO Transition”
American Superconductor Corporation press release (May 24, 2010)
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=1567401&highlight
American Superconductor Corporation (May 31, 2011)
American Superconductor Corporation (AMSC) has announced that the reporting of its financial
results for the fiscal year ending March 31, 2011, will be delayed and has requested an extension of up to
15 days to file its Annual Report with the Securities and Exchange Commission. The company stated that
additional time is required to prepare and audit the company’s financial statements for fiscal 2010, including
a review of some revenues associated with shipments to customers in China during the second, third, andfourth fiscal quarters; this review will most likely result in the reversal of the recognition of a material amount

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of revenue that the company had included when estimating revenues of “less than $355 million” for the full
fiscal year in a press release dated April 5, 2011.
To align its spending with near-term revenues, AMSC has implemented a hiring freeze and has
significantly reduced travel and discretionary spending in addition to reducing its global head count by 10%.
In addition, AMSC is reviewing options to secure additional financing that would enable the company tocomplete its acquisition of The Switch, a power technologies company headquartered in Finland.
AMSC’s financial results were adversely impacted by the refusal of Sinovel Wind Group Co., Ltd. toaccept shipments at the end of March 2011 as well as their failure to pay AMSC for certain contracted
shipments completed in fiscal year 2010. AMSC is continuing regular executive-level discussion with
Sinovel and expects that it will continue to do business with this customer.
Source:“AMSC to Delay Reporting Fourth Quarter and Fiscal Year End Financial Results”
American Superconductor Corporation press release (May 31, 2010)
http://phx.corporate-ir.net/phoenix.zhtml?c=86422&p=irol-newsArticle_Print&ID=1569300&highlight

NMR
Bruker (April 11, 2011)
Bruker has extended its Ascend™ series of high performance, compact NMR magnets to now covera range from 400 MHz to 850 MHz. Ascend magnets feature advanced superconductors and proprietary
magnet technology, enabling smaller, lighter magnet coils that allow significant reductions in physical size,
weight, magnetic stray field, drift, and cryogen consumption. In particular, Bruker’s proprietary
superconducting joint technology enables the drift behavior to be reduced by 50 % of the level featured by
the previous generation of magnets, thereby optimizing magnetic field stability. Together, theabove-mentioned features make Ascend magnets easier to site, safer to run, and l ess expensive tooperate.
Source:“Bruker Expands its Ascend™ NMR Magnet Series for Higher Performance, Easier Siting, and More
Economic Operation”
Bruker press release (April 11, 2011)
http://www.bruker-biospin.com/pr110411-5.html
Bruker (April 11, 2011)
Bruker has announced the release of the CryoProbe™ Prodigy, a game-changing CryoProbe thatenables a tremendous boost in sensitivity at an affordable price. The broadband CryoProbe Prodigy uses
nitrogen-cooled RF coils and preamplifiers to enhance sensitivity by a factor of 2 – 3 times compared withroom-temperature probes. The CryoProbe Prodigy is compatible with the Avance III™ line of NMR
spectrometers.
Source:“Bruker Announces Game-Changing, Affordable CryoProbe™ Prodigy for 3-fole Sensitivity Boost and
10-fold Throughput Enhancement for Routine NMR”
Bruker press release (April 11, 2011)
http://www.bruker-biospin.com/pr110411-1.html

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Bruker (April 11, 2011)
Bruker has received two separate orders for 395-GHz Solid State DNP-NMR systems that utilize
Dynamic Nuclear Polarization to enhance the sensitivity of solid-state NMR experiments. This new
instrument augments the field strength choices for commercial, high-performance DNP-NMR equipment.
The 395-GHz Solid State DNP-NMR system is comprised of a 395 -GHz gyrotron as the high-power
microwave source, Bruker’s Ascend 600-MHz 89-mm widebore superconducting magnet, and ul tra-fast
Avance™ III electronics for NMR detection. The first 395-GHz system will be i nstalled at Bruker’s USapplication facility, where it will be available for continued development, applied research, and customer
demonstrations. The first commercial 395-GHz system will be del ivered to the University of Guelph(Canada), while a second order for a 395-GHz system has been placed by the Max Planck Institute forBiophysical Chemistry (Germany). Dr. Werner Maas, President of Bruker BioSpin, commented, “We are
extremely pleased with these first orders for our novel 395 GHz DNP-NMR systems. The unique researchthat is ongoing, enabled by the sensitivity breakthrough offered via the DNP enhancement, is creating aparadigm shift in solid state NMR. We are confident that the adoption of this technology by theseoutstanding researchers will lead to very exciting new science in biological systems.”
Source:“Bruker Announces Two Major Orders for Novel High-Field 395 GHz Solid State DNP-NMR Systems in
Canada and Germany”
Bruker press release (April 11, 2011)
http://www.bruker-biospin.com/pr110412.html

MedicalElekta AB (April 18, 2011)
The Swinburne University of Technology (Melbourne, Australia) has acquired an Elekta Neuromag
TRIUX magnetoencephalography (MEG) system for studying brain activity. The system, which is scheduled
to become operational in mid-2011, will be sited in a new Advanced Technology Center. The MEG system
will be used to study cognitive and visual processes, neurological diseases/disorders, and mental healthdisorders.
Source:“Australian Center Readies Brain Research Program for Addition of Elekta MEG System”
Elekta AB press release (April 18, 2011)
http://www.elekta.com/healthcare_international_press_release_20071249.php

Basic
Brookhaven National Laboratory (April 12, 2011)
Researchers at the U.S. Department of Energy’s Brookhaven National Laboratory, in collaboration
with the Paul Scherrer Institute and t he University of Zurich in Switzerland, have di scovered thatsandwiching a barrier layer between two superconductors can enable superconducting behavior atsignificantly higher temperatures. The research builds on observations of the ‘Giant Proximity Effect’ noted

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in cuprates, in which the supercurrent is able to flow through a thick barrier. As thick layers are relatively
easy to fabricate, utilizing the Giant Proximity Effect could simplify on-chip device uniformity – a requirementthat has been a major technical hurdle for the development of large-scale integrated superconducting
electronics. To further explore the Giant Proximity Effect, the research group engineered complex cuprates
using molecular beam epitaxy to synthesize samples of thin films containing layers of lanthanum-cuprate
superconductors doped with varying levels of strontium—thereby creating a series of superconductors withvarying transition temperatures. The samples were then studied using a novel technique called low-energy
muon spin rotation to detect the presence of superconductivity in the outer and inner layers of each sample.
By mapping the magnetic fields, the researchers successfully observed the Giant Proximity Effect andfound that a thick barrier of superconductor with a Tc of 5 K was capable of transmitting a supercurrent at atemperature four times higher when it was sandwiched between two superconductors with a Tc of 40 K.
The group’s observations also confirmed that the entire barrier layer is affected by the Giant Proximity Effect.
The group’s work was published online in Nature Communications.
Source:“Giant Proximity Effect Enhances High-temperature Superconductivity”
Brookhaven National Laboratory press release (April 12, 2011)
http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=1263
Brookhaven National Laboratory (April 27, 2011)
Researchers at the U.S. Department of Energy’s Brookhaven National Laboratory (BNL) are using aprecise atom-by-atom layering technique to fabricate an ul trathin transistor-like field effect device forstudying the conditions that turn insulating materials into high-temperature superconductors. This transition
can be studied by applying an external electric field to increase or decrease the level of ‘doping’—i.e., theconcentration of mobile electrons in the material—and observing how such changes affect the ability of thematerial to carry a current. To accomplish this using cuprates, however, extremely thin and perfectly uniform
films, as well as an electric field measuring more than 10 billion volts per meter, are needed. The BNL teamused molecular beam epitaxy to create perfect superconducting thin films one atomic layer at a time,
precisely controlling the thickness of each layer. This technique was then applied to the fabrication of an
ultrathin superconducting field effect device that enables the charge separation necessary for theabove-mentioned studies to be achieved. Using this device, the researchers have found that as the densityof mobile charge carriers is increased, a cuprate film transition from insulting to superconducting behavior
occurs when the film sheet resistance reaches 6.45 kilo-ohm (exactly equal to the Planck quantum constantdivided by twice the electron charge squared). The results also suggest that in addition to electrons pairingin the superconducting state, the electrons also seem to form localized and immobile pairs in the insulatingstate—a condition not known to occur in any other material. The technical breakthrough enabling the
fabrication of the superconducting field effect device has been described in Nature.
Source:“Exploring the superconducting transition in ultra thin films”
Brookhaven National Laboratory press release (April 27, 2011)
http://www.bnl.gov/bnlweb/pubaf/pr/PR_display.asp?prID=1268
Rice University (May 3, 2011)
Researchers at Rice University have offered a theoretical explanation of how two dissimilar types ofhigh-temperature superconductors behave in similar ways. Specifically, they explained how the magnetic
properties of electrons in two dissimilar families of pnictides might give rise to superconductivity. One of theparent families of pnictides is a metal that was discovered in 2008; the other is an insulator discovered in

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late 2010. Each material, if prepared in a particular way, can become a superconductor at roughly thesame temperature. Theoretical physicists have been attempting to determine what might account for thesimilar behavior between such different compounds. The Rice University researchers believe that the
explanation involves subtle differences in the way the iron atoms are arranged in each material. Pnictides
are laminates that contain layers of iron separated by layers of other compounds. Chinese scientists
recently found a way to selectively remove iron atoms, leaving an orderly pattern of “vacancies” behind.
Qimiao Si, the lead researcher for the present paper, suspected that the similarities between the old andnew compounds could be explained by the way that electrons behave collectively as they are cooled to thepoint of superconductivity. Co-author Rong Yu elaborated, “We found that ordered vacancies enhance thetendency of the electrons to lock themselves some distance away from their neighbors in a pattern thatphysicists call 'Mott localization,' which gives rise to an insulating state. This is an entirely new route toward
Mott localization.” Second co-author Jian-Xin Zhu, a scientist at the Los Alamos National Laboratory, added,“What we are learning by comparing the new materials with the older ones is that these quasi-localized
spins and the interactions among them are crucial for superconductivity, and that's a lesson that can bepotentially applied to tell experimentalists what is good for raising the transition temperature in new families
of compounds.” Si concluded, “The new superconductors are arguably the most important iron-basedmaterials that have been discovered since the initial discovery of iron pnictide high-temperature
superconductors in 2008. Our theoretical results provide a natural link between the new and old iron-based
superconductors, thereby suggesting a universal origin of the superconductivity in these materials.” The
group’s theories have been published online in Physical Review Letters.
Source:“Study helps explain behavior of latest high-temp superconductors”
Rice University press release (May 3, 2011)
http://www.media.rice.edu/media/NewsBot.asp?MODE=VIEW&ID=15727
Boston College (May 21, 2011)
Researchers from Boston College, in collaboration with the Chinese Academy of Sciences, theNational Institute of Standards and Technology, Oak Ridge National Laboratory, and the University ofTennessee, have used neutron scattering and s canning tunneling microscopy (STM) to examine theinterplay between antiferromagnetism (AFM) and superconductivity. Their observations have revealed that
AFM, which was previously thought to be a r ival phase of superconductivity, may instead coexist withsuperconductivity. Using a copper oxide doped with additional electrons, the group observed that AFM
activity persists as t he high-temperature superconductor becomes superconducting. Specifically, theneutron scattering and S TM experiments revealed that spin excitations exist during both AFM andsuperconductivity. While neutron scattering can directly probe spin excitations, STM can identify the
behavior of the electrons. Together, this evidence shows the spin excitations in the electronic spectrum,
signaling that electron coupling has occurred. The results provide further evidence of the importance of spin
excitations to superconductivity in addition to providing a deeper understanding of the interplay between
various phases. The group’s research has been reported in Nature Physics.
Source:“Once thought a rival phase, antiferromagnetism coexists with superconductivity”
Boston College press release (May 23, 2011)
http://www.bc.edu/offices/pubaf/news/2011/madhaven05252011.html(Published in a Japanese version in the April 2011 issue of Superconductivity Web 21)
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Feature Article: Advancements in Superconducting Industrial
Equipment Technology- Trends in Superconducting Industrial Equipment Technology
Hiroyuki Ohsaki, Professor
Graduate School of Frontier Sciences
The University of Tokyo
An example of the industrial application of superconducting technology is the metallic Niobium-titanium(NbTi) superconducting wire magnets that are commercially employed for a silicon single-crystal pulling
process. As the magnets require cryogenic cooling the additional energy burden adds to the cost ofindustrializing this process. Nevertheless, this commercial application of superconducting technology has
been achieved due to both the fabrication of high quality and high performance materials and the realizationof an efficient process, enabling this technology to be accepted and diffused into the mainstream market
place since the mid 1990s. However, as the realization of a low-cost high temperature superconducting wire
remains an issue, it is hoped that high-temperature superconducting magnet technology leads to practicalapplications due to the superiority in operational performance offered and the contribution to energy
savings.
The Magnetic Billet Heating (MBH) method generates heat by rotating billets in a high magnetic field. Thismethod has attracted a great deal of interest in recent years as an alternative-heating route for non-ferrous
metal billet extrusion such as aluminum and copper. Since 2004, both Zenergy Power and Bültmann haveundertaken research and development in MBH, and in 2008, resulted with the installation of a heating
system in the aluminum billet extrusion factory of WeserAlu. The system clearly proved and verified thesuperior characteristics of MBH by heating a 6-inch diameter aluminum billet. The system was later also
installed in other regions of Germany and I taly for heating aluminum and c opper. The limiting
inhomogeneous temperature distribution within the billet has realized an improvement of the process
speeds and pr oductivity, producing an ef ficient system by reducing both operational and maintenancecosts.
In Japan, research and development of a High Temperature Superconducting Synchronous Machine is aflourishing area, attracting a significant deal of attention for the future development of motors for ships andcars.
The knowledge that a bul k superconductor holds superior magnetic flux pinning characteristics has
instigated research and development for many years towards an appl ication utilizing this characteristic.
Even though nothing has been achieved in terms of practical applications, it is highly expected that ongoing
research and development endeavors aimed for various potential applications will prove fruitful.
In February 2010, the Minister of Land, Infrastructure, Transport and Tourism, informed the Transport
Policy Council to hold an enquiry regarding Chuo Shinkansen connecting Tokyo and Osaka, in which the
public have a great interest. The enquiry focused on the assignments of company bodies responsible in thebusiness operations, the construction and infrastructure decisions regarding the plan for the proposed Chuo
Shinkansen. The discussion took place at the Chuo Shinkansen subcommittee meeting and the interim
report was submitted in December 2010. The report took into consideration the expected volume of
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demand and the construction costs in determining the optimum route for the Chuo Shinkansen, with theoption of the South Alps loop connecting its shortest distance as a pos sible route. Central Japan Railway
Company was deemed suitable as t he main body responsible for the business operations and t heconstruction of the routes from Tokyo and Osaka, with consideration of combined management benefits
with Tokaido Shinkansen, as well as their development experience in superconducting maglev technologies.
The Chuo Shinkansen is highly regarded as possibly the first superconducting maglev. The development,
verification and des ign have progressed towards the realization of practical technologies and sy stems,
targeting its first operation between Tokyo and Nagoya in 2027. In parallel, technological development is
continuously progressing, focusing on i mprovements in areas like cost reduction, low-cost maintenanceand system safety. It is strongly desired that these areas will not prove too challenging and therefore lead toa possibly early launch of business operations extending further to Osaka. However, an i mportantdevelopment theme for superconducting magnets is dependent on the future realization of hightemperature superconducting wire applications.
With the large numbers of potential future industrial applications, of superconducting technology it isimportant to focus on t he research and dev elopment for industrial equipment targets, which meets the
specifications required for practical applications. Current developments for high temperature
superconducting wires have led to improved wire performance characteristics, low-costs, advancements in
refrigeration cooling technologies and improvements in superconducting coiling technologies. It is therefore
desired that further research and development will contribute to producing a forerunner technology, leading
to the realization of future practical applications utilizing high magnetic fields, large electromagnetic force,
establishing applications with a high degree of functionality.
(Published in a Japanese version in the March 2011 issue of Superconductivity Web 21)

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Feature Article: Advancements in Superconducting Industrial
Equipment Technology- Advancements in Superconducting Magnetic Separation Systems
Shigehiro Nishijima, Professor
Department of Sustainable Energy and Environmental Engineering
Graduate School of Engineering, Osaka University
Activities ranging from fundamental to application-specific research and development for industrial
equipment have been undertaken in this field. These activities have impacted positively on the practical useof industrial equipment. This article discusses two types of industrial applications; (1) superconducting
magnetic separation technology for soil and u nderground wastewater purification and (2) a systemdesigned to remove iron from coal.
Firstly, water purification technology developed specifically for soil and underground wastewater isdiscussed. Developed in collaboration with Kajima Corporation and MS Engineering, the system employs a
Superconducting High Gradient Magnetic Separation (HGMS) method to collect and r ecycle ironparticulates from discharged wastewater that are used as reducing agents in soil and underground
wastewater purification construction work. Successful collection and recycling of these valuable, functional
iron particulates using magnets significantly reduced construction costs. The economic benefits were also
far-reaching with this technology. Those benefits contributed to promote soil and underground wastewater
purification methods (the so-called Enviro Jet method), and established a potential new field of application
where superconducting magnet technology can be applied. Especially in Japan superconducting magnets
were employed at a civil engineering site for the first time. The initial outcomes were positive andestablished the potential application of utilizing superconducting magnetic technology at an industrial scale.
Volatile Organic Compounds (VOCs), such as trichloroethylene, are the main chemical substances thatcause soil and under ground water contamination. A Jet Mixing method is currently utilized for on-site
removal of VOCs, purifying the soil and underground wastewater on the spot and eliminating the need for
bespoke transportation requirements. The method mixes water with functional iron particulates forming a
reducing agent, which is then transported down to the treatment ground by water-jet. The water-jet
transports the iron particulates deep underground, exactly where they are required and is beneficial as thetreatment process is done on the spot. However, the process has its shortcomings, with approximately half
the iron particulates jetted to the treatment site being discharged along with the wastewater to the surface,
increasing operational costs. It was envisaged that operational costs would decrease if more ironparticulates from the discharged wastewater were collected and recycled. By combining the Jet Mixing
method with superconducting magnets to collect and then recycle the iron particulates, we believe, would
increase the acceptance of the Jet Mixing method as the preferred choice of an on-site purification tool,
propelling its functionality into the mainstream market. To efficiently and econ omically collect ironparticulates with diameters of around 100 μm, superior method using high performance magnets are
required - (no other methods offers both the economic viability and efficiency other than magnetism).
However the following issues require resolution: 1) treatment capacity – the volume of discharged
wastewater is around 400 L/min. The process therefore needs to highly efficiently segregate ironparticulates using magnetic force from this flow of wastewater 2) the removal of the soil attached to the ironparticulates collected after magnetic separation. Even though the iron particles are magnetically separated
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and collected, efficient removal of the soil attached and pure metallic filtering when recycling is a must for
quality control issues. 3) The collection efficiency of the iron particulates from the discharged wastewater –poor collection efficiency increases operational costs. The HGMS method utilizing a s uperconducting
magnet is seen as the optimum route to address these issues.
To address the above-mentioned topics, the following methods were employed. For issue 1), the HGMS
method combining a superconducting magnet and magnetic filter was employed. During working conditions
the effectiveness of the magnetic separation was demonstrated with discharged wastewater flowing up to a
maximum of 500 L/min. For issue 2), a process combining powerful magnetic filter was introduced which
continuously filtered and washed off the soil attached to the iron particulates by the powerful magnetic force,enabling successful collection of almost pure iron particulates). For issue 3), demonstration of this process
at a actual construction site showed an iron-particulate collection efficiency from the discharged wastewater
greater than 98%, proving the viability of this method as a route to reduce construction operational costs.
A system removing iron from coal is now introduced. Zian Zhu, from the Institute of High Energy Physics,
Chinese Academy of Science, set up and developed a system to remove iron from coal at the Rizhao port
in China. Experimental testing at the site began in 2009, lasting one year. The tests showed that the system
served its intended application and in June 2010 was put into industrial use. The plan now is to build afurther 10 similar systems in the future. Previously, systems for iron removal from coal traditionally employedelectromagnets. However, due to rapidly increasing demands for coal in China, the necessity to improve
operational performance led to the development of a separation system using a superconducting magnet.
In 2009, China became a net importer of coal with the import volume rapidly increasing and with demand
set to increase even further. The insatiable appetite for coal is influenced by the rapid rise and advancementof high-coal consuming industries such as electricity, steel-making, building materials and chemicalindustries.
In China, coalmining uses dynamite to extract coal. This process occasionally leaves behind some
unexploded ordinance, which gets shipped together with the coal. A report from Ehime prefecture, Japan,
found four such unexploded ordinances in a shipment of coal from China destined for boiler fuel. It wastherefore recognized that to remove iron-related contaminants such as, detonating caps, wires andtransportation pipes from the coal was imperative. This is where a superconducting magnet has proved
crucial in the efficient magnetic separation of iron from coal and t he research and development of thisseparation system has already started.
With a total capacity of 10 million tons of coal per annum, this system is able to remove iron from coal(approximately 500 mm thick coal bed), load the coal onto a conveyor belt running at 5 m/s, running the
distance of 550 mm from the end. The superconducting magnet produces a magnetic field strength of 0.4 T
at the conveyor belt, 3 T at the center coil, rising to a maximum of 5.6 T. The system employs NbTi-based
superconducting wires (Cu ratio 4), equipped with a re-condensing refrigerator utilizing liquid Helium dipping
shaped coil. The dimensions of the magnet are thus; 900 mm internal diameter, 1200 mm external diameter,
360 mm height, operating at 165 A and pr oducing 224H of inductance. The cryostat bore at room
temperature is 630 mm, external diameter 1800 mm, with a height of 2200 mm, taking ten days to cool thecryostat. It is the future intention of Zian Zhu to follow on from this success and attempt to build a system toseparate iron-related compounds from Kaoline.
(Published in a Japanese version in the March 2011 issue of Superconductivity Web 21)
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Feature Article: Advancements in Superconducting Industrial
Equipment Technology- Development of Seismic Isolation Systems based on Superconducting
Magnetic Levitation
Makoto Tsuda, Associate Professor
Department of Electrical and Communication Engineering
Graduate School of Engineering, Tohoku University
Japan presently holds a strong international competitive position with a 40 % share of the world’s
semiconductor manufacturing equipment industry. Together with Taiwan, Korea, China and other South
East Asian countries, they account for approximately 80 % of the annual sales turnover of semiconductor
manufacturing equipment. However, these regions are seismically active with a l arge probability of alarge-scale earthquake occurring. The Chuetsu earthquake in 2004, in Niigata prefecture, Japan, wasestimated to have caused damages costing 70 billion yen. Current Seismic monitoring systems installed atsemiconductor manufacturing plants minimize damage to equipment and add a l evel of personnel safety.
Despite their advantages, these monitoring systems result in production stoppages that are estimated tocost 1 billion yen per day. Therefore, having technology that reduces manufacturing plant downtime or eveneliminates the need to stop manufacturing during earthquakes would be most desirable. Hence, such“seismic isolation” technologies are immediately required by industry. Precision tools in semiconductor
manufacturing plants employ vibration isolators to attenuate everyday micro vibrations transmitted from anarray of sources. However, when used in conjunction with seismic isolation systems, the seismic systemaffects the operation of the vibration isolators. For that reason, seismic isolation systems operating in
conjunction with vibration isolators are considered difficult in principle. However, the design of a seismic
isolation system utilizing superconducting magnetic levitation is considered a possible solution to overcome
this issue. This system is able to remove all horizontal vibrations from everyday fine vibrations toearthquake-related vibrations, regardless of vibration frequency or the amplitude transmitted. The seismic
isolation system therefore ensures the safety and relief of workers, eliminating production downtimes during
a large-scale earthquake.
Figure 1 show s a s chematic diagram of the
proposed seismic isolation system. It is composed ofthree layers – the permanent magnetic rail (thebottom/first layer), a bulk superconductor andpermanent magnetic rail (the middle/second layer),
and a top (third layer), bulk superconductor1). Figure
2 shows the principle of operation of the proposedsystem during a vibration test. The lowest layer isvibrated at an oblique angle to the horizontal (45degrees), with the middle layer constrained to movein one direction only (either left or right), with thein-plane movement removed between the lower andmiddle layers. The top layer of the seismic isolation
system remains stationary with the movement in theSummer, 2011

Fig.1 The seismic isolation system based onsuperconducting magnetic levitation.

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left or right directions suppressed between the middle and top layer. In order for the seismic isolation system
to suppress vibrations it is important that the magnetic field distribution is homogeneous in the longitudinal
direction of the permanent magnet. As the magnetic field gradient determines the levitation force on the
HTS bulk, in the longitudinal direction of the permanent magnet this magnetic field gradient does not exist.
Therefore the levitation force generated is dependent on the magnetic field gradient along the width of therail of the permanent magnet. In order to increase the levitation force further, research and development on
a hybrid system combining only permanent magnets (PM-PM system), with a HTS bulk and permanent
magnet (HTS-PM system) is currently under investigation. Permanent magnets arranged in a Hallbach
array are another ongoing research activity2-3). Results from this system design do indeed remove thehorizontal vibrations transmitted to the top layer, with transmissions due to micro vibrations measuring lessthan 1 % - equal to or better isolation efficiency than systems currently available. Research anddevelopment is still advancing with the aims of maintaining levitation stability when stationary and designingtechnology to suppress vertical vibrations.

Fig. 2 Employing the principle of superconducting magnetic levitation, a movie of the seismic
isolation system shows its operational effectiveness.

References:1) M. Tsuda, et al.: “Vibration Characteristics in Magnetic Levitation Type Seismic Isolation Device
Composed of Multiple HTS Bulks and Permanent Magnets”, IEEE Trans. on Applied Superconductivity 17(2007) 2059-2062
2) M. Tsuda, et al.: “Improvement of Levitation Force Characteristics in Magnetic Levitation Type Seismic
Isolation Device Composed of HTS Bulk and Permanent Magnet”, Journal of Physics 97-012104 (2008)
1-63) S. Sasaki, et al.: “Suitable Shape and Arrangement of HTS Bulk and Permanent Magnet for Improving
Levitation Force in a Magnetic Levitation Type Superconducting Seismic Isolation Device”, IEEE Trans. on
Applied Superconductivity 20 (2010) 985-988(Published in a Japanese version in the March 2011 issue of Superconductivity Web 21)

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Feature Article: Advancements in Superconducting Industrial
Equipment Technology- Development of High-Temperature Superconducting (HTS) Bulk Actuator
Seokbeom Kim, Associate Professor
Graduate School of Natural Science and Technology
Okayama University
1. The concept of HTS bulk actuator
Progress in HTS bulk research and development has led to greater critical current densities along withimproved mechanical strength, offering superior performance characteristics for highly expected
applications ranging from magnetic bearings, flywheels, conveyor systems and motors. Experimental
testing and numerical analysis on HTS bulk actuators that would allow remote operations in spatiallyseparated environments have been undertaken in our laboratory1-3). Figure 1 shows the development
concept of our superconducting actuator. It consists of 2-D arranged electromagnets, which form the stator,
the HTS bulk forming the rotor and a control system. The Field Cooling Method traps the HTS bulk actuatorand the drive current applied to the stators generates the 3-D magnetic field distribution giving the actuatorthe capability to move and rotate in both horizontal and vertical directions.

Fig. 1 A 3-D schematic of the superconducting actuator

2. Designs of the electromagnets
In order to establish stable levitation andoperational characteristics of the proposed
superconducting actuator, the magnetic field
distribution of the stator electromagnets aswell as controlling their strength are allimportant parameters. Initially two types ofelectromagnets were investigated. The left
hand side of figure 2 shows one portion of acylindrical electromagnet made to investigate
the operational characteristics. In order tohave finer control of movement and rotationof the actuator, 8-pole electromagnets wereSummer, 2011

92mm

iron core

92mm

wire windings

Fig. 2 Cylindrical shaped electromagnet (left hand side) and
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バルク体の捕捉磁場
The trappedmagnetic field (T)of HTS bulk

電磁石の発生磁場(T)
The magnetic
field of electromagnet(T)

constructed, which are shown on the right hand side of figure 2. The left-hand-side contour map in figure 3
shows the magnetic flux distribution generated on top of an energized 8-pole electromagnet arranged in a
NSNSNSNS pattern. The right-hand-side contour map in figure 3 shows the measured trapped magnetic
flux distribution of the HTS bulk.

Fig. 3 Magnetic flux distribution generated by 8-polar electromagnet at NSNSNSNS magnetization pattern (leftdrawing) and the trapped magnetic flux distribution of HTS bulk (right drawing)

電磁石の発生磁場(T) (T)
The magnetic
field of electromagnet

To improve the magnetic flux distribution and strength of the electromagnets, arranging the electromagnets
in a quadrangle shape, along with optimizing the design of the shape, the size of the iron core and thethickness of coil were undertaken. Measuring the characteristics of the electromagnetic fields by NumericalElectromagnetic Field Analysis when 10A DC is applied, measured diagonally (as indicated by the dottedline on top of electromagnets), of both the cylindrical (iron core diameter 28mmm) and quadrangle-shaped(iron core one side 28mm) electromagnets is shown in figure 4. The findings show that the magnetic flux
distribution is greater towards the inner side of the electromagnet, with a greater improvement in magnetic
field strengths of the quadrangular-shaped magnets. Further investigations comparing the characteristics ofthe cylindrical and quadrangular shaped electromagnets were undertaken. The levitation force applied to
the HTS bulk was measured as a function of the actual iron-core diameter under the same conditions foreach shape of electromagnet. The results show superior levitation characteristics of the quadrangularshaped electromagnet compared with the cylindrical electromagnet.
0.8
Quadrangular shaped electromagnet
四角柱電磁石

0.6
0.4

N

S

0.2

N

S

100

120

0.0

円柱電磁石

Cylindrical electromagnet

-0.2
-0.4

N

S

-0.6

N

S

-0.8
0

20

40

60

80

The diagonal length of top of the electromagnet (T)電磁石上部の長さ (T)Fig. 4 Magnetic field distribution characteristics of cylindrical and quadrangular-shaped electromagnet
geometries as measured by numerical electromagnetic field analysis
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3. Investigations of DC/AC drive current control methods
Figure 5 shows the schematic of the electromagnet assembly for the DC control system. Horizontaltransport occurs by switching either ON or OFF the DC current to each individual electromagnet. Figure 6
shows the measurement results of the levitation force applied to HTS bulk as a function of drive current
required. The findings show that different pole-pattern assemblies give rise to varying degrees ofrelationship between drive current and levitation force. At low drive currents, compared to NNSS patternarrangement, the NSNS pattern arrangement shows the magnetic saturation of the icon core assembly.
Although the DC control system is a simple technique providing drive currents to the individual
electromagnets by either switching ON or OFF, it does suffer drawbacks associated with HTS bulk
overshooting and having no speed control in its design. In order to address these issues, research isunderway into utilizing an AC control system to realize the smooth transport of actuator and speed control.
Figure 7 shows the electromagnets incorporating an AC control system, with figure 8 showing a contour
map of the pole patterns including the bulk superconductor. Numerical Electromagnetic Field Analysis isconducted on basis of Finite Element Analysis to determine the AC waveform utilized for AC control system.
Multiple bipolar power switches are used to investigate the dependency of frequency as well as thedependency of the magnetization gap4-5).
40

浮上力(N) (N)
Levitation
force

着磁電流
Magnetization
current
Iron cores

Coils

5A
10A
15A

30

20

10

N

S

S

N

z
y

0
0

x

15

20

Fig. 6 Measurements of the levitation force by DC control
Coil 1

Coils
N

S

z
x

10

Drive
current
(A)
駆動電流
(A)

Fig. 5 Schematic of the DC-controlled electromagnet

y5

Coil 3
N

N

N

N

S

S

S

Coil 2S

Coil 4

Coil 5

Coil 7

Coil 9

N

N

N

S

S

S

Coil 6

Coil 8

Coil 10Iron coresFig. 7 Schematic of the AC-controlled electromagnet

Fig. 8 Top view of the AC-controlled electromagnet
along with its corresponding pole pattern

References:
1) S.B. Kim, T. Inoue, A. Shimizu, S. Murase, “Development of 3-D superconducting actuator using HTS
bulks based on 8 poles electromagnets”, Physica C, Vol.463-465, pp. 1346-1351, 2007
2) J.H. Joo, S.B. Kim , T. Inoue, A. Shimizu, S. Murase, “Cap core design for high levitation force in 3-D

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superconducting actuator with HTS bulk”, Physica C, Vol.463-465, pp. 420-425,2007
3) S.B. Kim, T. Inoue, A. Shimizu, J.H. Joo, S. Murase, " Characteristics of a on 3-D HTS actuator withvarious shaped electromagnets", IEEE Trans. on Applied Superconductivity, Vol. 17, No. 2, pp. 2327-2330,
20074) S.B. Kim, D. Inoue, J.H. Joo, and Y. Uwani, " The dynamic characteristics of the HTS bulk
superconducting actuator driven with AC electromagnets ", IEEE Trans. on Applied Superconductivity, inpress5) S.B. Kim , Y. Uwani, J.H. Joo, Y.S. Jo, “The decay properties of the trapped magnetic field in HTS bulk
superconducting actuator by AC controlled magnetic field”, Physica C, in press(Published in a Japanese version in the March 2011 issue of Superconductivity Web 21)

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Feature Article: Advancements in Superconducting Industrial
Equipment Technology- Development of Conveyor System utilizing Superconducting Magnetic
Levitation
Mochimitsu Komori, Professor
Faculty of Engineering, Department of Applied Science for Integrated System Engineering
Kyushu Institute of Technology
Recent technological advances in superconducting magnetic levitation have instigated an increase in thenecessity of conveyor system applications. Utilizing the pinning force in a superconductor, efforts arefocused on the development of a stable levitation conveyer system without the need for complex control
systems and which consume no electricity for its levitation. A levitation conveyer system that employs
pulse-field magnetization (PFM) to overcome the inability to modify the levitation characteristics ofsuperconductors is currently under development.
Electromagnet utilized
for magnetization

Propulsion switch Propulsion magnet

Levitating
objectSuperconductor

Magnet power supplyＰ

Fig.1 The system overview

The overview of the system employed in this development work is shown in figure 1. A linear-induction
motor propulsion system is utilized in this study, consisting of a pulsed power supply to drive the magnets
and an AC-powered, three-layer switch required for propulsion. The superconductors, (dia 20 mm), arepositioned at the four corners of the container, fixed and then cooled by liquid nitrogen. Based on theanalysis of magnetic fields, we fabricated a magnetic rail shown by the schematic in figure 2. Permanent
magnets with their poles facing each other are arranged to concentrate the magnetic flux in the yoke of themagnetic rails. The magnetic yoke equalizes the magnetic field distribution along the magnetic rail. The
PFM (1) magnetization method combines the electromagnet into one section of the lower part of themagnetic rail. The magnetic field distribution generated by the PFM at the electromagnet is set in the samemagnetic field direction as the permanent magnet and designed to prevent the trapped magnetic field
distribution anomaly usually associated with a superconductor. The PFM (2) employs the electromagnets
described in the schematic shown in figure 1. The mechanism to magnetize from above enables the designof bigger electromagnets. The arm assembly shown in the figure moves in the direction indicated by thearrow and magnetically attaches to the conveyer. A decline in the magnetic distribution on the part of theelectromagnet used for PFM (1) results in a decrease in levitation height, however, the PFM (2) systemdesign improves this situation.

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鉄心Iron coreCoil

磁束密度[mT]
Magnetic
flux density [mT]Iron core

Permanent magnet

Permanent magnet

CoilElectromagnetic steel plate

500.0
400.0
300.0
200.0
100.0
0.0
-100.0-200.0-300.00 6 12 18

24 30 36 42

Y-axis [mm]361848 54 60

66

0X-axis [mm]Fig. 3 The measured magnetic flux densityof the magnetic rail

Fig. 2 The magnetic rail system

Figure 3 shows the results of the measured magnetic flux density in the Z direction, 1 mm above themagnetic rail. The magnetic flux density in the Y direction, located around 0 mm, is almost negligible eventhough the iron core of the linear propulsion motor is located there. The magnetic flux density of themagnetic rail shows very little change in the X direction. These results prove that stable levitation is possible.

Propulsion
force [N]
推進力[N]

Figure 4 shows the propulsion force when the levitation gap is increased to 3 mm. Aluminum coolingincreases the electrical conductivity leading to the measured propulsion force being seven times greaterthan at room temperature. Compared to the cooled aluminum itself and the aluminum combined withelectromagnetic steel plate, the magnetic flux concentrates onto the plate resulting in the measured
propulsion force being three times greater.
Aluminum (Room temp.)

1.5

Aluminum (Cooled)1

Copper (Cooled)
Electromagnet+ Aluminum(Cooled)

0.5
0
0

2

4

6

8

10

12

AC [A]

Figure 5 shows the relationship between thechanges in the levitation characteristics with the
maximum magnetic flux density, before andafter using PFM method (1). The initial levitation
gap was 5 mm, with applied voltages of 200 V
and 250 V for PFM method (1) and (2),respectively. For method (1), and maximum
magnetic flux density exceeding 0.2 T, thelevitation
characteristic
variesalmostproportionally to the magnetic flux density.

Summer, 2011

Changes in levitation
height [mm]
変位[mm]

Fig. 4 Propulsion force

0.4
reverse0.2

forward

0
-0.2
-0.4
-0.6
-0.4

-0.2

0

0.2

Maximum magnetic flux density [T]Fig. 5 Changes in levitation height for PFM method (1)© ISTEC 2011 All rights reserved.

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After utilizing method (2), the dispersion of magnetic flux density trapped in the superconductor wasmeasured 1 mm above the surface of the superconductors. Figure 6 shows the trapped magnetic flux
density generated in the forward direction, when the pulse-field is applied in the same direction as thepermanent magnets. Figure 7 shows the trapped magnetic flux generated in the reverse direction, or when
the pulse-field is applied in the opposite direction to the permanent magnets. The findings reveal thatchanges in the trapped magnetic field by the PFM method was confirmed on the surface. However, when
operated in the reverse direction subsurface changes in the magnetic field were small. The results
demonstrate that PFM can be employed to change the levitation height as it is largely related to the trappedmagnetic field generated at the subsurface compared to the surface.

100.0

80.0 -100.0
60.0 -80.0
40.0 -60.0
20.0 -40.0
0.0 -20.0-20.0 -0.0

80.0
60.0
40.0
20.0
0.0

4

-20.0
0

4 8
12

Y direction [mm]

14
16 20

24

100.0
60.0
40.0
20.0
0.0
-20.0

X direction [mm]2480.0 -100.0
60.0 -80.0
40.0 -60.0
20.0 -40.0
0.0 -20.0-20.0 -0.0

80.0

4
0

4 8
12 16

Y direction [mm]Fig. 6 Trapped magnetic field distribution
in the forward direction

14
20 24

24

X direction [mm]Fig. 7 Trapped magnetic field distribution
in the reverse direction

Reference:
1) R. Maruo et al., “Study on magnetically levitated conveying system using hybrid-magnetized high Tc
superconductors,” IEEE Trans. on Applied Superconductivity, 18, 820, 2008.
(Published in a Japanese version in the March 2011 issue of Superconductivity Web 21)

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Feature Article: Advancements in Superconducting Industrial
Equipment Technology- Advancements in Superconducting Motor Technology for Ship
Propulsion
Toshiyuki Yanamoto, Director
R&D Division of Machine Systems
Technology Research Laboratory, Kawasaki Heavy Industries, Ltd.
Steep rises in oil prices, global warming prevention and tougher international regulations of exhaustemissions, has forced the marine industry on reducing fuel consumptions and cutting carbon emissions
even further. Technology is being developed to replace the conventional diesel ship propulsion systems withelectric propulsion systems operated using a superconducting motor. The superconducting motor
consumes less electric power and is more compact allowing it to fit into restricted spaces on board a ship,enabling a ship hull design to become more streamlined with less water resistance. Another benefit is to
reduce energy loss since the motor drives the ship’s propellers directly without the reduction gear. Together,
these advantages of superconducting technology can significantly reduce the fuel consumption.
It is a recent memory that in the USA a 36.5 MW power-output superconducting motor for ship propulsion
was recently developed, successfully completing full-load tests1). In Europe as well as in Korea, megawatt
power-output superconducting motors for ship propulsion have been under developing2). In Japan,
superconducting motors have been developed utilizing a bulk superconductor in a rotating magnet
pole-filed3) as well as axially arranged iron-core coils made from Bi-based wires4). A recent development of
megawatt-class superconducting motor5) has been rapidly advancing with join efforts form Kawasaki Heavy
Industries, Ltd, Tokyo University of Marine Science and Technology, National Maritime Research Institute,Japanese Super-conductivity Organization Co., Ltd, and Sumitomo Electric Industries, LTD. The research
efforts of this group have led to the development of a prototype system (shown below), with a designed
power output of 1MW. Just last year, the group has demonstrated that when two out of six superconducting
coils were installed on each pole the motor’s output reached 450kW, an outstanding efficiency rate of 98% the highest record in Japan. The results from these tests imply that the motor’s power output will reach
1MW when all superconducting coils are installed. With support from NEDO, the group is continuously
carrying out research and development activities to realize a 3MW power-output superconducting motor by
2012.

Megawatt-class superconducting motor
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The challenges remaining include, testing the long-term operation and the endurance with varying
external loads of the superconducting motor. Additionally, the developments of a highly efficient coolingsystem enable to withstand ship motions in stormy sea states, performance enhancements of hightemperature superconducting wires and further cost reduction are necessary for the potential futureapplications for superconducting motors in the maritime industry. It is highly expected that research anddevelopment advances further towards the realization of these applications at industrial level in the near
future.
References:1) http://www.amsc.com/products/motorsgenerators/shipPropulsion.html2)http://www.siemens.com/innovation/en/news_events/ct_pressreleases/e_research_news/2011/e_22_res
news_1109_2.htm
http://www.doosan.com/doosanheavybiz/en/services/green_energy/superconducting.page3) http://www2.kaiyodai.ac.jp/~izumi/pressrelease/PRESSRELEASE060701HP.pdf
4) http://www.ihi.co.jp/ihi/press/2007/2007-9-03/index.html
5) http://www.khi.co.jp/news/detail/20101101_1.html(Published in a Japanese version in the March 2011 issue of Superconductivity Web 21)

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Feature Article: Advancements in Superconducting Industrial
Equipment Technology- Development of High Temperature Superconductor
Induction/Synchronous Machine (HTS-ISM) for Transportation
Equipment Applications
Taketsune Nakamura, Associate Professor
Department of Electrical Engineering, Graduate School of Engineering
Kyoto University
Utilizing high temperature superconductor windings in a squirrel-cage design, the group’s research anddevelopment aims are the High Temperature Superconductor Induction/Synchronous Machine (HTS-ISM)
for transportation equipment applications1). This project was launched as the “2009 Energy Conservation
Technology Development Project (Second Public Offering)”, commissioned by NEDO (New Energy andIndustrial Technology Development Organization). Over the short interval of one year and three months anddue to the efforts of project members at the forefront in this industry, as well as strong backup provided by
NEDO, the following outcomes have been achieved.
Initial research steps involve experimental study on fully-superconducting HTS-ISM installed in several
small, kW-class machines. Investigations proceeded cautiously as there have been no successful reports ofa fully-HTS with high-speed synchronous rotation modes exceeding 1000 rpm in radial-gap shaped
synchronous machines. Initial investigations thus focused on the stator windings with particular effort
dedicated to employing a racetrack double pancake coil and searching for optimum coil assembly andcooling methods. The hard work resulted in successful synchronous rotation at 300 rpm2) followed shortly
by successful continuous synchronous rotation at 1800 rpm3). By taking advantage of the nonlinear current
transport characteristics of the HTS windings in a squirrel-cage design, we experimentally confirmed the slip
rotational mode as fail safe, developed analysis code for transient characteristics4) based upon voltage
equations and tested the characteristics of stable rotation control5).
Following on from the success of above-mentioned small machine, a 20KW-class prototype machine
was developed with the understanding that the limiting characteristics such as, critical currents
characteristics in the iron core3) and allowable bending radius6), be those characteristics currently offered bycommercially available HTS tapes. The design aim of this prototype machine has been to minimize thestator size by investigating factors such as electromagnetic field analysis, coil magnetomotive force and the
HTS coil shape geometry. A prototype coil was thus fabricated from HTS tape that met the agreed
characteristics. Detailed measurement tests were undertaken to determine the DC and AC transportcharacteristics3), current transport characteristics within the iron core7) as well as certain reproducibility.
Furthermore, considering that the iron core is placed in a cryogenic temperature environment, several
candidate materials were evaluated by standard measurement methods for their brittleness8) and iron loss
characteristics9) at cryogenic temperatures. Based on the measurement results, a silicon steel sheet was
selected as the offering the best characteristics and therefore employed to fabricate a prototype stator aswell as rotor core. Various trials were undertaken to optimize the fabrication process and technology
necessary to produce the windings for both the HTS stator as well as the rotor. The 20KW-class machine
was finally completed after an optimum construction process to produce the HTS windings required for thisSummer, 2011

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core was achieved. Although a great deal of time and effort was required to reach this stage, importantknowhow and knowledge was gained.
A small-sized cryostat developed for the 20kW-class prototype machine was designed to minimize
thermal invasion and developed a cooling mechanism to reduce thermal stresses. Furthermore, various
elaborate shaft designs were also prepared. Integrating the 20kW-class prototype machine with the cryostat
was finally accomplished producing the drive motor system. The machine is currently undergoing various
tests and the results from those tests will be forthcoming.
In parallel, a compact and highly efficient cryocooler for transportation equipment was fabricated using a
Stirling-type cryocooler developed over time by Aisin Seiki Co. Repeated detailed investigations on thecompressor performance yielded a COP of 0.07510) at 77K – close to a world record. We anticipate
achieving a COP of 0.1 soon.
This report highlights the ongoing research and development efforts at our research group aimed at
HTS-ISM applications for transportation equipments such as, hybrid cars, trains and ships. For example,
the development of hybrid cars utilizing applications of superconducting technology is still a large hurdle toclimb, however we see the possible realization in future applications for cars exceeding M-size, but
excluding large, MPVs or vans. Of course the realization of applying this technology to other forms oftransportation is potentially viable and therefore our research and development endeavors will continue withthe aim of bringing HTS-ISM technology into the mainstream in the not too distant future.
References:
1) Taketsune Nakamura, Feature Article: Advancement in Superconducting Industrial Equipment
Technology “Advancement in Superconducting Motor Technology for Electric Car”, Superconductivity
Web21, 5 (March 2010).
2) “A Successful Synchronous Test of Fully Superconducting Induction/Synchronous Machine! – Momentum
towards Research and Development for HTS Drive Motor System applied for Car!” Kyoto University, Imura
Materials Research Laboratories, Research Institute of Applied Science, Niigata University,
Superconductivity Communications (SUPERCOM), vol.19, no.3 (June 2010).
3) Taketsune Nakamura et al., in preparation.
4) Kazuhiro Matsumura, Taketsune Nakamura, Toshiharu Nishimura, Rikiya Asai, Daisuke Sekiguchi
Naoyuki Amemiya, “Evaluation of HTS-ISM Power Load Characteristics measured by Analysis Model” at
2009 Autumn Meeting of Cryogenic and Superconductivity Society of Japan held at Okayama University,
Okayama city, 1B-p07, (Nov 2010)5) Hiroki Kitano Taketsune Nakamura, Daisuke Sekiguchi, Shintaro Misawa, Yusaku Kawanishi, Naoyuki
Amemiya “Investigation of HTS-ISM Stability Behavior”, The Institute of Electrical Engineers of Japan (IEEJ)National Conference 2011 held at Osaka University, Osaka city (March 2011), Submitted6) Kozo Osamura, Taketsune Nakamura, Yoshitaka Ito, Masaaki Yoshikawa, Toshihisa Terazawa, “Critical
Current Characteristics of DI-BSCCO Tapes during Bending at Low Temperatures”, 2010 Autumn Meetingof Cryogenic and Superconductivity Society of Japan, held at Kagoshima Public Access Center, Kagoshima
city, 2A-A04, (Dec 2010)
7) Tatsumori Futakuchi, Tatsuya Maekawa, Jun Ogawa, Satoshi Fukui, Tetsuo Oka, Takao Sato, Taketsune
Nakamura, Kozo Osamura, “Iron Core AC Loss Characteristics of HTS wires”, 2010 Autumn Meeting of
Cryogenic and Superconductivity Society of Japan, held at Kagoshima Public Access Center, Kagoshima

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city, pp1-26, (Dec 2010).
8) Kozo Osamura et al., Not yet published
9) Masaki Miyamoto, Tetsuji Matsuo and Taketsune Nakamura, A Measurement of Vector Hysteretic
Property of Silicon Steel Sheet at Liquid Nitrogen Temperature, 11th International Workshop on 1 & 2
Dimensional Magnetic Measurement and Testing, Oita, Japan (2010.11)
10) Not yet published(Published in a Japanese version in the March 2011 issue of Superconductivity Web 21)

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Feature Article: Advancements in Superconducting Industrial
Equipment Technology- Magnetic Billet Heater
Yukio Ogawa, Advisor
Kyokuto Boeki Kaisha, Ltd.
1. AC induction heating and its limitations
Since the 1920s1) AC induction heating has been used in the metal processing industry. The metallic
billets for extrusion are placed inside a copper magnetic coil through which an AC current is applied
generating an alternating magnetic field. The alternating magnetic field induces eddy currents within themetal billets, and based upon Joule’s law, generates heat by the electrical resistance of the materials. The
coil is usually made from water-cooled copper tube to prevent it from melting. For the AC induction process it
is the copper coil heating that causes the biggest energy loss. In the case of aluminum heating the energy
efficiency of this process is typically 40 to 50 %.
Thus there is room for improvement in the heating process itself. Conventional induction heating employs
AC frequency with 50/60 Hz producing eddy currents mainly at the surface of the billet, which take time toheat the entire billet uniformly. Process adjustments are always necessary for AC induction heating as theheating efficiency is dependent upon a number of factors such as, the dimensions of the billet, the alloy
composition and the power source employed.
2. A new approach involving DC magnetic heating
Metal induction heating system utilizing DC power source was studied during the 1950s. However, it wasmore than 30 years later that this was actually realized, in 19902), when an inventor in the USA published amethod for DC induction heating with powerful magnets. This method was understood to offer a number ofadvantages over conventional AC induction heating, however the required technology for DC induction
heating to become a reality was not economically viable at that time. Today, however, with industriallymanufactured superconducting wires and advanced solid-state drive motors have enabled the realization of
DC-powered magnetic heaters for commercial applications3-6). The process of magnetic heating is simple intechnological terms offering far greater energy efficiencies than currently offered by AC induction heating.
Additionally, billets are heated up with uniform temperature and faster, thereby preventing damage causedby surface over-heating effects.
July 2008 saw the first commercial operation of a DC-powered magnetic heater. The coil operated with apower input of 10W, with zero-resistance electricity flow through a superconductor, is able to generate astrong enough magnetic field necessary to induce heating. As the magnetic field of the DC-powered coildoes not vary with time, the billet rotates within the magnetic field inducing eddy currents. However, eddy
currents in the material oppose rotational motion forming powerful braking torques, which can only beovercome using electric motors of a size of 100-500 kW. Thus, it is the highly efficient motors that are
responsible for billet heating rather than inefficient AC induction coils. Within the rotating billet the energy
consumed by the motor is transformed to heat. A schematic of the magnetic induction heater shown on theleft-hand-side of figure 1 converts more than 80% of the energy consumed by the motor into heating within
the billet.

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Fig. 1 Energy Loss of HTS magnetic induction heating (left figure) and AC induction heating (right figure).

The effects of utilizing “mechanical” rather than “electrical” frequency resulted in heat energies generated
by DC-powered magnetic heating penetrating three times deeper than using AC induction heating process,with no surface effects, providing a more uniform heating profile. Furthermore, the faster heating process
removes the risk of local-meltdown of the material and reduces the soaking time for the billets to achieve a
uniform temperature profile. Experiments to investigate the temperature profile of aluminum billet, measured
by the thermocouple and tap hole, recorded a temperature difference from one end to the other of thealuminum billet, as well as from the centre to the surface of the aluminum billet of ±6°C, compared to ±15°C
for an AC induction heating.
3. Simple technical design

Fig. 2 Schematic drawings of the magnet billet heater

As shown in figure 2, the main system of the magnetic heater is the superconducting magnet. The
refrigeration system to keep the magnet at its operational temperature is composed of off-the-shelfcomponents that are commercially available in refrigeration technology. The magnetic field generated by thesuperconducting magnet passes through two thermally insulated heating chambers that house the rotating

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billets. Electric motors placed in each chamber provide the rotational energy required for induction energy.
The motor is able to slide to receive billets with different lengths, with the hydraulic system supplying theclamping pressure to the motors to stabilize the billet. All the heat generated goes into heating the rotating
billets. Compared with conventional gas heaters and AC induction heater, DC magnetic heater is not
subjected to significant temperature increases, vibrations or any other mechanical stress factors.
4. Experiences gained from the installation and the operation
The machine is designed to be set-up easily and quickly at site. The compact footprint of the machine
ensured that it is easily integrated into the existing production layout. The target temperature of aluminum
billet due to homogeneous temperature could be 30 °C lower than that for conventional process. The lower
billet temperature made possible the extrusion of aluminum with more complicated and detailed shapes.
Moreover, the quality of the surface finishes is improved. The magnetic billet heater increased the
productivity by an average of 25 %, with the heating cost of aluminum billets reduced by approximately 50 %when compared with conventional AC induction heating.
1) Tudbury, C.A., Basics of Induction Heating, John F. Rider, Inc., New Rochelle, NY, 1960.
2) Mohr, G.R., Industrial Heating Magazine, May, 1990, p. 24.
3) Masur, L.J., J. Kellers, S. Kalsi, C. Thieme, and E. Harley, ”Industrial HTS Conductors: Status andApplications,” 2004 Institute of Physics Conference Series, 2004, pp. 181, 219.
4) Runde, M. & N. Magnusson, IEEE Transactions on Applied Superconductivity, 2003, 13 1612.
5) Magnusson, N., European Patent 1582091 B1.
6) Magnusson, N. and M. Runde, ”A 200 kW MgB2 Induction Heater Project,” Journal of Physics:
Conference Series 43, 2006, pp. 1019–1022.
(Published in a Japanese version in the March 2011 issue of Superconductivity Web 21)

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Feature Article: Advancements in Superconducting Wires/Tapes
Technology- REBCO Coated Conductors
Teruo Izumi, Director
R&D Division of Superconducting Tapes and Wires, SRL/ISTEC
Considering the numerous benefits of cost, in-field characteristics, mechanical strength and ac loss in
REBCO coated conductors, development of REBCO coated conductors have made remarkable progressin the national projects mainly in Japan and USA over the past 10 years. The past 10 years has seen thebenchmarking characteristic value of Ic（critical current) x L（length) being fiercely contested by researchers
world-wide, in particular in both Japan and USA who were always competing to ensure the top spot. In
August 2009, SuperPower reported an IcL = 300 kAm（Ic =282 A/cm width, L=1062 m). After a brief research
update interval, in autumn 2010, Fujikura reported results with IcL = 375 kAm (Ic =609 A/cm width, L=615m)
with IBAD-PLD tapes. Furthermore, this year Fujikura improved on the previous value by reporting an IcL =467 kAm (Ic = 572 A/cm width, L=816m).
The rapid technological advances of REBCO coated conductors have led to recent developments ofapplication devices using them. However, the timing of some applications with their specifications required
implies that certain characteristics are not mature and still requires development, e.g. improvement in tapecharacteristics such as, the in-field strength Ic characteristics, and ability of mass production with high speed
and low cost. Additionally, requirements from the applications vary and the specifications currently required
exceed what is presently available today. Thus, recent research and development trends for REBCO
coated conductors have focused on component technology in order to meet the specifications required
from the applications.
Fundamental research for improvement of in-field characteristics has initially focused on short-tapedevelopments for motor and SMES applications that utilize magnetic fields for their operation. Deposition
with BZO nanorods using Pulsed Laser Deposition (PLD) and BZO nanodots using Metal Organic
Deposition (MOD) have been taken place by many researcher activities to disperse artificial pinning centers.
However, these deposition methods have not as yet extended to develop longer tapes, as there are only a
few reported examples of research undertaken with longer tapes. The market leaders in this field areSuperPower, and together with Houston University, reported the introduction of BZO nanorods to the
YGdBCO superconducting tapes using MOCVD. The stability of the material in a magnetic field wasinvestigated with the addition of Zr, Y and Gd, achieving a current density of ～100 A/cm width @1 T, ～20
A/cm width @3 T at 75 K. With a view to keep processing costs down a high-rate fabrication process was
adopted by ISTEC in Japan, which deposited a thick, high current density (Jc) film of GdBCO by PLD. With
50 m wires, we achieved tape characteristics 1.5 times greater than those already reported by SuperPower,with characteristics of 33A/cm width @3 T at 77 K.
Japan leads the way in the development of thinner, low AC-loss tapes aimed for power generation
applications such as, cable and transformer applications. In recent findings, IBAD-MOD deposited tapes in
addition to IBAD-PLD tapes, showed that for a 50 m length of tape scribed into five-parts along its width, theAC loss was limited to 20 %. A bespoke tape winding technique for coiling was also confirmed responsible
for the reduction in ac loss. Even though SuperPower has demonstrated a reduction in ac loss for short
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lengths tape, there are currently no published reports attributing the effectiveness of coil design in reducing
loss. As more recent topics in this field, ISTEC and Kyushu University has discovered a new phenomenonof drastically small levels of hysteresis loss for REBCO coated conductors with a highly textured tstructure.
Research is still at an early stage and thus further experiments will be required to confirm the phenomenon,
however the implications of this research are significant possibly leading to an array of future applications.
Whilst Japan leads the world in developing individual component technology targeted for specificapplications, the USA still remains one step ahead, with mass production potential. In Japan, technologicaldevelopment in this field has been mainly supported under the national projects, with business sponsorshipjust recently beginning to emerge. In the USA, AMSC and SuperPower have built up mass production
capabilities with AMSC for example, having already over 700 km of annual production capabilities. It is mybelief that further technological realizations of applications are around the corner with numerous research
reports regarding the price of superconducting tapes are recently emerging. By 2015, SuperPower isaiming to produce tapes priced at around $50/kAm, and Fujikura is targeting to supply 500 A wires at 3000
yen/m (6 yen/Am) by 2015. A South Korean company, SuNAM, have recently aroused worldwide attention
by joining the tape production and sales arena, publically declared their long-term vision to supply tapes
priced at $80/kAm by 2015, and $25/kAm by 2023.
The recent developments in Japan and abroad of REBCO coated conductor technologies have been
discussed. Research and development tape characteristics based solely on Ic L benchmarks are no longer
reliable measures of performance. Recent technological developments are focused on application-specificrequirements, with additional characteristics such as in-field characteristics and low AC-loss becoming
important benchmarks to determine tape performance. It is considered that these trends in tapedevelopment will trigger further technological advancements aimed more towards the establishment ofmass production and low cost manufacturing and further accelerate the development of tapes for practicalapplications.

(Published in a Japanese version in the April 2011 issue of Superconductivity Web 21)

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Summer, 2011

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Feature Article: Advancements in Superconducting Wires/Tapes
Technology- Performance Enhancements of Bi-based Superconducting Wires
Kazuhiko Hayashi, General Manager
Application Development Department, Superconductivity & Energy Technology Division
Sumitomo Electric Industries, LTD.
1. The process of critical current improvement
Sumitomo Electric Industries, LTD. is producing high-temperature superconducting wires made from
(Bi,Pb)2Sr2Ca2Cu3Oy（Bi2223) under the trade name of DI-BSCCO. They are fabricated by sintering the
combined raw materials in a metal tube by the PIT (Powder In Tube) method. The wires are formed into a
4.3 mm wide tape with a thickness of approximately 0.23 mm. The superconducting tape is embedded in asilver matrix and has a multi-filamentary architecture to provide thermal stability and robustness.

Critical Current Ic 77 k, Self magnetic field (A)400

Short length wire sample of m orderLong length wire of Km orderHighly energy-saving
equipment level(actual equipment level)

300

250A
200
Mass production
level

Pressure
sintering

100

0Long lengthof km order1990 1995

Prototype demonstrationequipment level

Principle verificationequipment level2000

2005 2010

Wire fabrication technology(development is entrusted to JST)
Development of pressure
sintering technology
Discovery of Bi-based high temperature （CT-OP DI-BSCCO)

2015

2020

Year

superconducting material (Maeda, et al.)Fig. 1 Sequence of events showing the improvements of Bi-based high temperature superconducting wires

Figure 1 shows the sequence of events that improved critical current capabilities of Bi-based wires. The
initial stages of the development and up until 1995, the PIT method with silver became established as
fundamental process producing 1 km-class prototype wires. During this time the manufacturing process
improved gradually enhancing the critical current characteristics, for a given size of wire achieving 100A at
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liquid nitrogen temperatures under a self magnetic field. However, it was the development of the pressure
sintering method that greatly enhanced wires characteristics. The method reduced local defects thatconsequently led to improvements in production yields and contributed in improving critical current
capabilities as well as increasing mechanical strengths, allowing the Bi-based material system to achieve astatus usually reserved for industrial goods. After this, improvements at every manufacturing process stepalong with the optimization of process parameters for various wire samples, resulted in wires achieving
critical currents (77.3 K, under self magnetic field) of 250 A – 233 A for 15 m sample and 200 A for km-classlong wire samples, respectively. Presently, a long wire capable of carrying 160-180 A is available for supply
at an industrial level. A wire with a high Ic is presently in the middle of mass production process development
and a long wire capable of carrying 200 A is estimated to be available at industrial level in the foreseeable
future.
2. Others
Without requiring large capital investments the production capacity is estimated to double from current
levels of 500 km per annum to 1,000 km per annum in the near future. If demands increase further, it isconsidered to increase production capacity to meet the demand.
With the variety of applications envisaged for superconducting wires, the characteristics of the criticalcurrent are benchmarked according to their liquid nitrogen temperatures and the self magnetic fields. Thus,
for applications such as electric cables, it is possible to directly compare the characteristics under the low
magnetic field in liquid nitrogen. For magnet applications at 20-30 K, magnetic fields of several T are appliedvertically against the wires. Figure 2 shows the magnetic field characteristics at low temperatures of
DI-BSCCO wires produced using a standard manufacturing process. High temperature superconducting
pinning characteristics at low temperature have been understood to be dependent upon carrier density. By
adjusting the carrier density in the same sample, occasionally leads to greater improvements in themagnetic field characteristics at low temperatures than that represented in figure 2. Currently, this data is
being collected and summarized along with further investigations into supplying optimized
application-specific superconducting wires for the future.

77 K, s.f.
Ic(trial sample)
241 A
182 A
Ic(standard Type H)

30 K, 3 T
277 A
205 A

20 K, 3 T
423 A
320 A

Fig. 2 Magnetic field characteristics at low temperatures(Published in a Japanese version in the April 2011 issue of Superconductivity Web 21)
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Feature Article: Advancements in Superconducting Wires/Tapes
Technology- Process Advancements in MgB2 Wire Technology
Hiroaki Kumakura, Managing Director
Tsukuba Magnet Laboratory
National Institute for Materials Science
MgB2 has a higher Tc than conventional metallic superconductors along with strong inter-grain coupling
occurring without the need for additional orientation processing. Together with the low cost of Mg and B raw
materials these attributes are advantageous for practical applications for MgB2 wires. Companies havealready started manufacturing MgB2 wires in excess of 1 km. A research group in Italy has demonstrated an
open-type MRI system based on MgB2 wires cooled by a cryogenic refrigeration system. Hospital
experimental testing of the MRI system has been undertaken with further research and development
geared towards future applications.
The so-called PIT method is the mainstream technique currently employed to fabricate MgB2 wires. The
in-situ PIT method starts off with constituent Mg and B powders, experimentally adding various impurity
materials into the powder mix in an attempt to improve the superconducting characteristics. The addition ofnano SiC into the powder mix is well documented, however the additions of carbon nanotubes andfullerenes have contributed to large improvements of Jc, especially in high magnetic fields. It is understoodthat C substitution on the B site is behind both the improvements of Jc and Hc2. The addition of organic
materials such as hydrocarbon (C9H12) and carbonhydrate (C4H6O5), all have been reported to result in
improvements of Jc. Compared to the addition of nano SiC, the findings confirm remarkable improvements
in Jc with lesser C substitution on the B site. However, the mechanism by which this occurs is still not wellunderstood.
In general, the in-situ fabrication methods of MgB2 wires results in a very low filling factor of around 50 %because of the volume shrinkage occurring when Mg and B powders are heat-treated to form the MgB2
compound. Numerous efforts to improve the filling factors have been attempted. One such method is the
Hot Press or Hot Isostatic Press (HIP) method delivering an improvement in Jc, two or three times greatercompared to ordinary heating treatment. However, fabricating long wires is proving difficult via this method
and still needs to be addressed. On the contrary, Cold Isostatic Pressing method is considered a suitableprocess to fabricate longer wires. In fact, flat wires produced by simultaneously subjecting all four sides of
the wire to pressures of 1.5 GPa followed by an ordinary heat treatment have a filling factor closer to 60 %,with a Jc twice as large at 4.2 K, increasing to approximately eight times as large at 20 K and 7 T.
Reports show that mechanical alloying is an appropriate mixing and reaction technique that improves thefilling factor, yielding homogeneous nanocrystalline MgB2 superconductors. It is the formation of thesepartial MgB2 nanoparticles that act as the core seeds promoting the formation of the MgB2 layer. Thesefindings enable researchers to reduce heat treatment temperatures even further and to improve upon thegrain boundary pinning characteristics.
Additional processing routes to obtain high-density MgB2 layers involve diffusion reacting a pure Mg rod
with boron powders. A metal sheath tube with a coaxial internal pure Mg rod is filled with amorphous boron
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powder packed densely into the space between the Mg rod and the metal sheath tube. This composite iscold worked to a wire. During heat treatment the Mg diffuses into the boron layer leading to the formation of
MgB2.
Recent findings from wires produced using this method have shown remarkably high Jc values thanpreviously. From measurements at 20 K and 3T, Jc values in excess of 100 kA/cm2 have been recorded.
However, as Jc shows rapid decline with increasing a magnetic field, further improvements in wire
characteristics are crucial for practical applications utilizing stronger magnetic fields. Additionally, Je(calculated for the total wire cross-sectional area) is still too low and it is necessary to improve Je to evenhigher values by means of advanced microstructure control and cross sectional geometries.

(Published in a Japanese version in the April 2011 issue of Superconductivity Web 21)

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Date of Issue: July 15, 2011

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Feature Article: Advancements in Superconducting Wires/Tapes
Technology- Advancement of Iron-based Superconducting Materials
Keiichi Tanabe, Deputy Director General
SRL/ISTEC
It has been three years since the research group directed by Professor Hosono, of Tokyo Institute ofTechnology, discovered iron-based superconducting materials. Followed by copper-oxide based
superconductors, iron-based superconductors form a second group of high temperature superconducting
materials. Professor Hosono’s group first published on their discovery of LaFeAs (O,F) with a Tc of 26 K in
February 2008. This led to a flurry of activity with many groups from both Japan and abroad focusing theirresearch efforts on this new breed of superconducting materials. Just two months after the initial findings it
was reported that by substituting La with Sm increased the Tc to 55K. The iron-based systems have many
compositional permutations available, each offering the potential of discovering materials exhibiting evenhigher Tc’s. As with the copper-oxide superconducting material systems, the peculiar physicalcharacteristics of the iron-based material system are totally different from metallic superconductor systems.
Despite concerted fundamental research efforts at the national level, projects launched in Japan, Germany
and China have not yet yielded a Tc higher than 55 K. Nevertheless, together with some 30 types of newiron-based materials discovered to date, the research has led to a better understanding of the physicalcharacteristics. Additionally, the progress development on applications involving wires and electronic
devices has been gradually made. The aim of this article is to briefly introduce recent researchadvancements mainly relating to applications.
The iron-based superconducting materials discovered to date all have a layered structure similar tocopper-oxide and from the point of layer structure can be categorized into four major classes as shown bytable 1. Charge carrying in superconductors occurs via the tetrahedral networks composed of iron,pnictogen (As and P) or chalcogen (S, Se, Te). The first system discovered consisted of an iron-containing
layer, alternately stacked with the tetrahedral layers of RE-O (rare-earth oxides), and now often referred toas 1111 system. The addition of alkali-earth metals (Ca, Sr, Ba) and alkali metals (Li, Na etc) alternately
layered in the iron structure produced the 122 and 111 systems, respectively. A simple iron-based layered
structure incorporating chalcogens became known as the 11 system. Other than those four categories,
many other material systems having a perovskite-like block layer structure have been found. Among thesefour major classes, the 1111 and the 122 systems with a maximum Tc of 38 K have an upper criticalmagnetic field Bc2, equally as high as the Y-based copper-oxide system. Also, anisotropy is an importantparameter for wire applications. The 1111 system has an anisotropy of 5 and is close to the Y-based
copper-oxide system. However the 122 system has an anisotropy ranging from 1.5 to 2, as small in size asthat measured in MgB2.
A group based at the Chinese Academy of Science has from the initial stages investigated the fabricationof iron-based superconducting wires using the Powder In Tube (PIT) method, aiming their research anddevelopment for potential future applications for wire technology. The group reported that with Fe sheathwires, (superconducting materials (Ba,K)-122, Ag as additions and Ag for internal sheath), they achieved
results showing a maximum self-field Ic of 37.5 A (Jc> 3750 A/cm2), at a temperature of 4.2 K. However, Ic
drops rapidly in a magnetic field, indicating that inter-grain coupling is weak. In Japan, the National Institute
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of Materials Science (NIMS) is making efforts to fabricate wires of the 11, 122 and 1111 material systems
using the PIT method. Prototype multi-core wires containing 7 cores based on the 11 system have been
fabricated. For the 122 system Ag sheath wires, NIMS has recently reported a self-field Ic of 60 A, with large
improvement of Jc of 104 A/cm2. In the presence of a magnetic field, Jc initially drops rapidly but in a highmagnetic field of around 18 T, the Jc remained around 103 A/cm2. Thus, these findings suggest that it ispossible to fabricate wires for use in strong magnetic fields at low temperatures.
Table 1. Categorization and characteristics of the iron-based superconducting material system
Material system

1111 system

122 system

111 system

11 system

Material
composition

ZrCuSiAs

ThCr2Si2

PbFCl

PbO

Materials
and TcLaFeAs(O,F) 28 K
La(Fe,Co)AsO 14 K
NdFeAsO1-y 55 K
SmFeAs(O,F) 55 K
Ca(Fe,Co)AsF 22 K
LaNiBiO
4K(Ba,K)Fe2As2 38 K
(Sr,K)Fe2As2 38 K
Ba(Fe,Co)2As2 23 K
BaFe2(As,P)2 30 K
BaNi2P2
3K
KxFe2-ySe2 32 K

Anisotropy γ

5

1.5 - 2

LiFeAsNaFeAs

18K
15K

FeSe
8K
FeSe(*1) 27 K
Fe(Se,Te) 15 K
Fe(Se,Te) (*2)21K

1-2(*1) Under Pressure, (*2)Thin Film

The fabrication of high quality epitaxial films is vital to gain an understanding of the grain boundary
characteristics essential for wire applications and to investigate the potential device applications. The 122
material system (Tc of 20-25K) carrier-doped by Co substitution is relatively easy to fabricate as a thin film.
Reports from University of Wisconsin, Tokyo Institute of Technology and IFW Dresden in Germany, alldemonstrate the fabrication of a high quality thin film based on the 122 material system. Within theframework of Funding Program of World-Leading Innovative R&D on Science and Technology sponsoredby Japan Society for the Promotion of Science, Professor Hosono’s group at the Tokyo Institute ofTechnology and ISTEC jointly fabricated a high quality thin film on a bicrystal substrate to investigate the Jc
dependency on misorientation angle and grain boundary characteristics. The findings showed that whilst
there was no significant drop in Jc when the misorientation angle was less than 9°, there was however an
exponential drop in Jc when the misorientation angle was greater than 9°, demonstrating that the grainboundaries were weakly coupled. The critical misorientation angle where there is an obvious weakinter-grain coupling is in fact twice larger than that compared to the Y-based copper-oxide system and theslope of Jc at high angles is not as well pronounced. The characteristics of both the copper-oxide and theiron-based superconductors are similar as it is the carrier doping which induces superconductivity. However,the differences in grain boundary characteristics appear due to differences in the carrier-depleted parent
materials for the copper-oxide and iron-based material systems, which exhibit insulating and metallic
behavior, respectively. This implies that the deposition of a high Jc superconducting thin film on a metal
substrate with a textured buffer layer is carried out relatively easily. In fact, this method is currently used tofabricate Y-based copper-oxide tapes. The IFW Dresden group has recently reported their attempts of a
122 thin film deposited on a metal substrate using a textured IBAD buffer layer. On the other hand, the grainboundary formed at a misorientation angle of more than 30° forms an ideal Superconductor-Normal
metal-Superconductor (SNS) type Josephson junction, and has been employed in a SQUID, jointly tested
at the Tokyo Institute of Technology and ISTEC. The fabrication of a higher Tc 1111-based high quality
superconducting thin film was delayed as the carrier doping by F replacement proved difficult. However, aSummer, 2011

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research group in Nagoya University, using MBE, successfully realized a Tc greater than 50 K by diffusing F
from an Nd-O-F thin film stacked on top of a Nd-1111 thin film. Using a similar deposition approach, a
research group based at Tokyo University of Agriculture and Technology recently achieved a thin film with azero Tc at 53 K. Further evaluation trials on the superconducting characteristics such as the Jc in a magnetic
field are ongoing.
As introduced above, the current iron based superconducting material system presently offers thepotential for applications operating mainly at low temperatures and in high magnetic fields. It is expectedthat discoveries of new materials with even higher Tc and smaller anisotropies are forthcoming. A majority ofthe materials with high Tc’s that have been discovered up to now contain poisonous arsenic. I would like topoint out as a conclusion that it was only last year that a material system (KxFe2-ySe2), containing no arsenic,
with a Tc of 32 K was discovered.
(Published in a Japanese version in the April 2011 issue of Superconductivity Web 21)

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