October, 2014

Date of Issue: October 15, 2014

Superconductivity Web21
Published by International Superconductivity Technology Center
KSP, Kawasaki, Kanagawa 213-0012 Japan Tel:+81-44-850-1612, Fax:+81-44-850-1613

Contents:

Topics:- What’s New in the World of Superconductivity
Feature Article: ’SQUID Forum on Superconductivity Technology Trends 2014’-2- High-temperature SQUID Application to Natural Resources Development and Non-destructive
Testing- Application of High-temperature SQUID Magnetometers for Measuring Magnetic Variations
Associated with Earthquakes- Superconducting Sensor Applications for Astronomical Observations – ALMA International Project- Exploring Novel Superconducting Materials- High Field Magnets- Overview of Projects Undertaken Worldwide

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http://www.istec.or.jp/web21/web21-E.html
This work was subsidized by JKA using promotion funds from KEIRIN RACE
http://ringring-keirin.jp
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October 2014

Date of Issue: October 15

Superconductivity Web21
Published by International Superconductivity Technology Center
KSP, Kawasaki, Kanagawa 213-0012 Japan Tel:+81-44-850-1612, Fax:+81-44-850-1613

What’s New in the World of Superconductivity초전도 뉴스 –세계의 동향超导新闻-世界的动向-chāo dǎo xīnwén

- shìjiè de dòngxiàng-

Yutaka Yamada, Principal Research Fellow
Superconductivity Research Laboratory, ISTEC★ News sources and related areas in this issue►Power Application
Nexans, LS Cable, RWE Deutschland AG and STI Jointly Exhibit Solutions at
CIGRE 2014
STI, Nexans, LS Cable, RWE Deutschland AG (25 Aug, 2014)
Superconductor Technologies Inc. ("STI"), together with Nexans, LS Cable and RWE Deutschland AG,
showcased the attributes of superconducting fault current limiters (SFCLs) and high power superconducting
cables (HPSCs) at STI's CIGRE.

October, 2014

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October 2014

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The joint goal is to leverage the collective expertise of the companies and share the value proposition of
SFCLs and HPSCs with companies poised to develop the infrastructure, electricity transmission anddistribution industries. This aims to support decision makers with critical planning network, broadening themarket appeal of future infrastructure to optimize existing power systems and improve the stability andreliability of the grid.
Adam Shelton, STI’s VP on Marketing and Product Line Management, said “Superconducting wire is a key
component of the overall solutions. In conjunction with our plan to begin producing our Conductus® wire incommercial volumes later this year, we are working closely with our SFCL and HPSC customers to
optimize performance and improve capacity to meet industry demands.”
Source: “Nexans, LS Cable, RWE Deutschland AG and STI Jointly Exhibit Solutions at CIGRE 2014”
STI Press Release (25 August, 2014)
http://phx.corporate-ir.net/phoenix.zhtml?c=70847&p=irol-newsArticle_Print&ID=1960572&highlight
Contact: Cathy Mattison invest@suptech.com►Wire
750km/year Throughput of the 100mm wide and 1km long Wire
STI (7 August, 2014)
Superconductor Technologies Inc. (STI), reported their results for the second quarter ending June 28, 2014.
STI's net revenues for second quarter 2014 were $75,000 compared to $389,000 in the first quarter of 2014
and $555,000 in the second quarter of 2013, mainly from legacy wireless products. Over this period, STI
recognized a one-time gain of $3.5 million from its investment in Resonant Inc. For the six-month period
ending June 28, 2014, total net revenues were $464,000, compared to $1.3 million for the first half of 2013.
In the second and third quarter, the company shipped 11 orders; six for Stage 1 customers conducting
performance evaluation and five for Stage 2 customers testing simulated devices for commercial
deployment. Their customers are employing Conductus wire for multiple applications such as
superconducting fault current limiters, high performance magnets, power cables and nuclear magnetic
resonance equipment. Five of the 11 shipments were to new customers. Also, during the same period, thecompany received five new orders and project commitments. STI reports the shipping of 20 Conductus wireorders over the past year.
STI's president and chief executive officer, Jeff Quiram, stated, “The company has completed theinstallation and calibration of characterization equipment that allows STI to test their Conductus wire thathas reported performance attributes of up to 1,000 Amps on 1 km lengths.” The company aims thetransition from pilot plant equipment to 1km production equipment that is designed to produce 750
kilometers of Conductus wire at widths of 100mm annually. After delay of their original plan, commercial
volume production is still expected in the fourth quarter and the ramp to full capacity to being early 2015.
Source: “STI Reports 2014 2Q Results”
October, 2014

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October 2014

Date of Issue: October 15

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STI Press Release (7 August, 2014)
http://phx.corporate-ir.net/phoenix.zhtml?c=70847&p=irol-newsArticle_Print&ID=1956390&highlight
Contact: Cathy Mattison invest@suptech.com►NMR
Portable NMR
Harvard School of Engineering and Applied Sciences (4 August, 2014)
A research team led by Donhee Ham, Gordon McKay Professor of Electrical Engineering and Applied
Physics and his student Dongwan Ha, based at the Harvard School of Engineering and Applied Sciences(SEAS), together with the Schlumberger-Doll Research Center in Cambridge, Mass., and the University ofTexas, Austin, have created a portable nuclear magnetic resonance (NMR) spectroscopy device. The
research team successfully managed to shrink the electronic spectrometer components onto a silicon chip.
By combining this with a compact permanent magnet, the spectrometer is the smallest device currently
able to perform multidimensional NMR spectroscopy, as Ham states, “one of the most powerful analytical
tools to determine molecular structures at atomic resolution.”
Current state-of-art NMR systems employ large superconducting magnets for interrogating the structure ofcomplex molecules. However, Ham says, “In many circumstances-for example, many experiments inbiochemistry or organic chemistry, quality control in production lines, or chemical reaction monitoring –you’re doing NMR on smaller molecules, and for those applications the big superconducting magnets may
be avoided.” Permanent magnets are weaker than superconducting magnets, but still perform satisfactorily
to resolve small-to-medium size hydrocarbons, drug compounds, and biomolecules. Stability concerns
associated with permanent magnets due to thermal effects have been overcome by calibrating using
statistical distance minimization and entropy minimization to estimate the magnetic field drift.
Ham and Ha also see other potential portable applications combining this tiny spectrometer chip with alarger superconducting magnet to speed-up the analysis of complex molecules by performing many NMR
spectroscopy experiments simultaneously. Ham says, “Using a hundred of these cheap and small
spectrometer chips in parallel within a superconducting magnet bore could counter the intrinsic slowness of
NMR spectroscopy, enabling a high-throughout paradigm for pharmaceutical screening and structural
biology. One year of testing could be completed in a few days. We have already started investigating thisangle.” The research team has filed for a provisional patent on the miniature NMR spectrometer. Together
with Harvard’s Office of Technology Development (OTD), they are currently exploring potential avenues forcommercialization with pharmaceutical companies involved in drug discovery, as well as from companies
poised to deliver next-generation equipment for spectroscopy applications.
A research paper highlighting the NMR system comprising a compact permanent magnet was published in
the Proceedings of the National Academy of Sciences (PNAS).
Source: “Minuscule chips for NMR spectroscopy promise portability, parallelization”
October, 2014

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October 2014

Date of Issue: October 15

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STI Press Release (4 August, 2014)
http://www.seas.harvard.edu/news/2014/08/minuscule-chips-for-nmr-spectroscopy-promise-portability-parallelization
Contact: Caroline Perry►Basics
Large Grant of $1.9 million for the HTS mechanism
Brookhaven National Laboratory (12 August, 2014)
Ivan Bozovic, a Brookhaven physicist and an Adjunct Professor at Yale University has been awarded a
grant of $1.9 million over five years by the Gordon and Betty Moore Foundation as part of the foundation’s
Emerging Phenomena in Quantum Systems (EPiQS) initiative. The grant is aimed at unlocking the secretsof high-temperature superconductivity, particularly investigating the fabrication and manipulation ofsuperconducting thin films and exploring factors that lead to the ability of certain materials to carry electricity
with no energy loss.
Bozovic quoted, “I am very grateful for this grant, which recognizes the importance of methodical work thatslowly but steadily improves materials synthesis techniques and sample quality.”
A bespoke molecular-beam epitaxy (MBE) machine has been built by Bozovic, allowing the fabrication ofenhanced superconducting thin films, an atomic layer at a time. More than 2,000 thin film samples havebeen fabricated, together with hundreds of scientific experiments conducted. The atomic-layer-by-layer
synthesis technique enabled Bozovic to make a series of discoveries that bring interface superconductivity
to the forefront of research in condensed matter physics. The findings have demonstrated that a superfluid
can be confined to a single atomic layer at the interface of two materials, neither of which issuperconducting. Additionally, it was ascertained that electron pairs exist on both sides of thesuperconductor-to-insulator transition, which provide an important insight to the high-temperature
superconductivity phenomenon.
Source: “New Grant to Aid Search for the Secrets of Superconductivity”
BNL Media & Communications Office (12 August, 2014)
http://www.bnl.gov/newsroom/news.php?a=25024
Contact: Karen McNulty WalshRole of Magnetism in Iron-based Superconductors
ORNL (21 August, 2014)
Researchers based at the Department of Energy’s Oak Ridge National Laboratory and Vanderbilt
University are challenging the current knowledge of superconductivity and magnetism in iron-based
superconductors. Previous thinking was that magnetism and superconductivity could not coexist since
October, 2014

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October 2014

Date of Issue: October 15

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superconductors conventionally repel magnetic fields. Experimental evidence using a combination of
scanning transmission electron microscopy and electron energy loss spectroscopy to characterize themagnetic properties of individual atoms shows that rapid fluctuations of local magnetic moments iscorrelated with a high critical temperature, and can influence the performance of iron-based
superconductors.
The team undertook a comprehensive four-year study that analyzed several families of iron-based
superconductors, revealing universal trends among the compounds. They determined the total number anddistribution of electrons in atomic energy levels that determine the local magnetic moments, concluding thatthe number of electrons doesn’t change, but what changes are the positions and distribution of electrons indifferent levels and thus why the magnetic moments differs across families.
This research was conducted in part at the Center for Nanophase Materials Sciences, a DOE Office of
Science User Facility. The research at ORNL was supported by the DOE’s Office of Science. Idrobo andZhou based at Vanderbilt University were supported by the National Science Foundation. The research is
published as “Orbital occupancy and charge doping in iron-based superconductors” in Advanced Materials.
Source: “ORNL scientists uncover clues to role of magnetism in iron-based superconductors”
ORNL News Release (21 August, 2014)
http://www.ornl.gov/ornl/news/news-releases/2014/ornl-scientists-uncover-clues-to-role-of-magnetism-in-iro
n-based-superconductorsContact: Morgan McCorkle

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October 2014

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Feature Article: Forum on Superconductivity Technology Trends 2014
- High-temperature SQUID Application to Natural Resources
Development and Non-destructive Testing
Keiichi Tanabe, Director General
SRL/ISTEC
A magnetic sensor utilizing a superconducting quantum interference device (SQUID) exhibits high magnetic
field sensitivity in the femtotesla range (fT = 10-15T), leading to the commercialization of clinical equipment
including magneto-encephalogram and magneto-cardiogram having more than 50-100 channels of
so-called low-temperature SQUID sensors fabricated from niobium thin films. Such equipment can perform
high precision measurements with a magnetically shielded enclosure that completely shields it from theeffects of geo-magnetism. High-temperature SQUID sensors on the other hand, comprising of RE123
high-temperature superconducting thin films, have the additional advantage of being easily cooled using
liquid nitrogen, which is readily available around the world. Demonstrations with such sensors undertaken inrecent years have shown their effectiveness in practical field applications, without the need for magnetic
shielding e.g. in natural resource exploration, and therefore has broadened their appeal for an array of
applications. The progress in sensor technology has been realized by undertaking advanced mounttechnology, including efficient cooling and external noise suppression, in addition to the improved sensitivity
performance and magnetic field tolerance characteristics of high-temperature SQUID sensors.
The International Superconductivity Technology Center (ISTEC), has developed a high-temperature
SQUID magnetometer for the next-generation transient electro-magnetic system (SQUITEM 3), aimed at
the exploration of metal resources, andcommissioned by the Japan Oil, Gas andMetals National Corporation from 2010 to 2012.
The system induces an eddy current deep
underground from a coil located at the groundsurface. The magnetic field attenuation of theinduced current is measured and analyzed by a
SQUID magnetometer installed at the center ofthe coil, enabling depth profiles and the
distribution of specific resistance variations inunderground to be determined. The SQUID
magnetometer is very compact as shown in
Figure 1, and allows a day’s exploration to be
performed with only 1ℓ of liquid nitrogen. The
SQUID
sensorisfabricatedfromFig. 1 SQUITEM 3 developed by JOGMEC’s
ISTEC-developed multilayer thin film technology,
commissioned development projects. The cylinder on
attaining both the high magnetic field sensitivity
the left is the ISTEC-developed magnetometer; right isand flux-trap tolerance characteristics required
the receiver developed by Mitsui Mineral
Development Engineering Co., Ltd.
for such an application. SQUITEM 3 canOctober, 2014

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respond to rapid field variation with the application of a coil current an order of magnitude larger compared
to a conventional system. Performance attributes of SQUITEM 3 are not only due to the enhanced sensor
performance, but also contributed by electromagnetic shielding housing the magnetometer, which
effectively shields unwanted noise frequencies of more than 100 kHz during measurements.1),2)
Demonstration field trials of this system have been undertaken at a mining district in Australia, allowing theverification of its superior exploration depth capabilities compared to electromagnetic exploration systems
utilizing conventional sensors such as flux gate and induction coils. From 2013 onwards, the system was
employed for actual exploration in South America and other areas.
ISTEC has been developing SQUID sensor technology
aimed for monitoring CO2, which was injected into the oillayer for enhanced oil recovery (EOR), commissioned by
the Oil & Gas Upstream Technology Unit, JOGMEC
since 2012. Here, utilizing differences in specificresistivity of CO2 and water-repellent oil layers, thedistribution of specific underground resistivity in thehorizontal direction is evaluated by similar methods
usually undertaken by electro-magnetic systems formetal resources exploration.3) However, since the oillayer is located 2000-3000m below the surface it isnecessary to operate each magnetometer and coil in theborehole drilled. This means that it is required that the
SQUID sensor operate and withstand the extreme
environments found inside a borehole, which cantypically include pressures of 30-70 MPa andtemperatures of around 200°C, as well as operate in
restricted space. Additionally, the steel pipe casing that is
also inserted during borehole drilling rapidly attenuates
Fig. 2 Injection of the SQUID magnetometerhigh frequency magnetic signals. Thus, the highinto a trial borehole containing a steel pipesensitivity characteristics of SQUID sensors even at low
casingfrequencies are seen as an advantage. Under the“Technical Solutions Project 2013” conducted by JOGMEC, ISTEC was responsible for the development of
the SQUID magnetometer component technology. A pressure and thermal tolerant plastic enclosure having
a small external diameter of about 80mm has been fabricated, offering less impact on electro-magnetic
measurements compared to metals. A demonstration trial confirmed its pressure and thermal tolerant
characteristics. As shown in Figure 2, the magnetometer was injected into water and placed 50m deep into
a trial borehole containing a steel pipe casing that was drilled into the Kashiwazaki test field of JOGMEC.
The low-noise operational characteristics of the SQUID sensor and receipt of a coil signal from more than
100m has been successfully realized. Over the next couple of years, the research team aims to establish
fundamental technology that will enable the SQUID magnetometer to operate safely and reliably inborehole depths of more than 1000m. This technology is also anticipated for the exploitation of otherresources, including geothermal prospecting and submarine resource exploration in the future.
Similarly, for non-destructive testing applications the high sensitivity performance characteristics of theOctober, 2014

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SQUID sensors at low frequencies can prove to be advantageous. For example, when a SQUID isemployed in an eddy current test (ECT), a method typically employed to detect surface defects in metals
components, detection will be made possible at much greater material depths, such as detecting defects on
the rear section of a pipe. Fundamental experiments demonstrating such capabilities have been
undertaken in aluminum and Inconel multilayer samples, confirming a certain level of performance
attributes to detect deep-level defects.4) Furthermore, other applications anticipated include areas withpotentially significant needs in maintaining industrial infrastructure such as chemical and power generation
plants, where corrosion and thinning of heat insulating pipes can occur. The current issues with regards tonon-destructive testing are requiring a clear view of the target and also to demonstrate the significant
superiority afforded by a SQUID sensor over conventional methods. Typically, non-destructive testing
locations experience greater noise sources and testing accessibility is often limited. This overturns theconventional wisdom and wide held view concerning conventional SQUID sensors. However, the author
considers that the utilization of assembly component technology developed during studies for resource
applications will pave the way for their practical use.
Research introduced in this forum, was partially undertaken under the JOGMEC’s commissioned
development projects including “Technical Solution Project 2013” and the “Development of Next Generation
SQUITEM Equipment and SQUID Magnetometer 2010-2011”. We would like to express our gratitude topersons concerned in JOGMEC.
Reference:
1) JOGMEC NEWS, vol. 34, p. 8, Sept. 2013.
2) T. Hato, A. Tsukamoto, S. Adachi, Y. Oshikubo, H Watanabe, H. Ishikawa, M. Sugisaki, E. Arai, and K.
Tanabe, Supercond. Sci. Technol., vol. 26, p. 115003, Nov. 2013.
3) JOGMEC, Annual report of Oil Engineering Development, p.110 , 2012.
4) J. Kawano, T. Hato, S. Adachi, Y. Oshikubo, A. Tsukamoto, and K. Tanabe, IEEE Trans. Appl.
Supercond., vol. 21, p. 428, June 2011.

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Feature Article: Forum on Superconductivity Technology Trends 2014
- Application of High-temperature SQUID Magnetometers for Measuring
Magnetic Variations Associated with Earthquakes
Kan Okubo, Associate Professor
Information Communication Systems, Faculty of System Design
Graduate School of System Design, Tokyo Metropolitan University
The author and his research group have relentlessly conducted field studies investigating the Earth’s
magnetic field. Amongst the observations include the direct and dynamic magnetic signals emanating fromearthquake rupturing, measured successfully for the first time in Japan/abroad when the Iwate-Miyagi
Nairiku Earthquake struck on 14 June, 2008.1) The observations revealed a gradual but clear magnetic
variation from the onset of the earthquake.

Fig. 1 Seismic waves detected at the Hosokura Observation site (HSK) in Miyagi prefecture, at the onset of
the Iwate-Miyagi Nairiku Earthquake (A) Acceleration, (B): Magnetic field in the vertical direction

Magnetic variations were observed prior to the seismic wave reaching the observation site, and thus, theassumption is that the magnetic field begins to change in the epicentral area simultaneously with the onsetof earthquake rupturing.
Magnetic variations can be transmitted to the observation site at almost the speed of light. Therefore, it is
proposed that direct magnetic signals variations from earthquake rupturing enables the prompt detection ofearthquakes, potentially offering the development of a new system providing “ultra” early warning of
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destructive earthquakes with the combined magnetic and seismic measurements.
However, to realize this system an outstanding issue remains to be solved, i.e. the sensor sensitivity used inmagnetic field observations. The degree of magnetic variations observed during the Iwate-Miyagi Nairiku
Earthquake was around several 100 pT, measured at the Hosokura observation site, situated at a distanceof 26km from the epicenter of the earthquake. In fact, the levels of magnetic signals vary according togeographic influences including distance, angle, and depth from the epicenter. Thus, in some cases, this
implies that the degree of magnetic variations measured could be much smaller, and therefore suggeststhat ultra-high sensitive magnetometer technology are inevitable to continuously undertake observational
studies towards the realization of practical system in the future. In other words, pico-tesla class highly
sensitive magnetometers are required to clearly observe the degree of magnetic signals associated withearthquake rupturing.
The author and his research group have progressed the development of a high-temperature SQUID(HTS-SQUID) magnetometer system specifically aimed for studying the Earth’s magnetic field. The
characteristics of an HTS-SQUID magnetometer are considered advantageous because; (1) threecomponents of magnetic fields can be measured with greater sensitively; (2) extremely good temperature
characteristics, and; (3) operating costs are minimal since superconductivity can be sustained using liquid
nitrogen. In particular, long-term observation of terrestrial magnetism is required. Sustaining
superconductivity utilizing liquid nitrogen is therefore advantageous from the viewpoint ofmulti-observational sites required in the future. Thus, this offers greater promise in realizing practicalsystems.
The author and research group has established the Iwaki observation site (IWK) at Iwaki City, (Fukushima
prefecture), to enable continuous observation of the Earth’s magnetic fields using a HTS-SQUID
magnetometer. Constant observation is now ongoing (Figure 2, Figure 3). Currently, the system operation isstable and has acquired some magnetic variations associated with earthquakes. Further data accumulation
studies is planned to determine the future feasibility of this system for practical use.

(a)

44ºN

40ºN

36ºN

HSK
KAK

M9.0 Tohoku EQIWKAftershock Area

140ºE

144ºE

Fig. 2 Observational sites and the map of Japan

October, 2014

Fig. 3 HTS-SQUID magnetometer for
terrestrial magnetism observation studies© ISTEC 2014 All rights reserved.

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Reference:
1) K. Okubo, et al., "Direct magnetic signals from earthquake rupturing: Iwate-Miyagi earthquake of M 7.2,
Japan, EPSL 305, 1, pp. 65, 2011.

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Feature Article: Forum on Superconductivity Technology Trends 2014
- Superconducting Sensor Applications for Astronomical Observations –ALMA International Project
Yoshinori Uzawa, Director
Terahertz Collaborative Research Center
Terahertz Technology Research Center
National Institute of Information and Communications Technology

Fig.1 ALMA telescope constructed in the Atacama Desert, 5,000m above sea level (photo of mountaintop facility)

The Atacama Large Millimeter/submillimeter Array (ALMA) located in the Atacama Desert, 5,000m above
sea level, in north region of Chile, South America, is the largest ground-based radio-astronomical telescope
jointly constructed in a project involving East Asia, North America and Europe (Figure 1 shows the “AOS”
mountaintop facility). Amongst the millimeter and submillimeter wavelengths heterodyne receivers to beinstalled in all of the 66-unit parabolic antennas that make up the telescope, the National Astronomical
Observatory of Japan has been developing and manufacturing superconducting receivers designed forBand-4 (125-163 GHz), Band-8 (385-500 GHz), and Band-10 (787-950 GHz). The development of theBand-10 receiver covering the highest frequency ranges of those receivers at ALMA was launched in 2005,
with manufacturing/testing for all the receivers completed in 2013. This article presents the summary
outcomes from the viewpoint of the author based at the National Astronomical Observatory, who was incharge as leader of development of the Band-10 receiver.
The most challenging performance specifications required by the ALMA project was the receiver noise
temperature, (which had to be less than five times the quantum noise). Band-10 exceeds the gap
frequency of niobium (Nb), which has been conventionally utilized in such applications. The author and his
development team have therefore developed a new niobium titanium nitride (NbTiN) superconducting
material that has led to the successful demonstration of a SIS-mixer, exhibiting the world’s lowest noise
performance characteristics. All 73-unit receivers (including spares) that were shipped to Chile, havesatisfactory demonstrated the challenging specifications required by ALMA. Figure 2 shows the minimum
noise at each frequency measured by those receivers, which measured around three times the quantum
noise, thereby virtually attaining the performance characteristics equivalent to conventional Nb receivers
operating at lower frequencies. Furthermore, AOS has seen the world’s first successful terahertz
interferometer test using 2-unit antennas, each of which is equipped with a Band-10 receiver (Figure 3). The
superior receiving performance attributes have been verified.1)
Reference:1) http://alma.mtk.nao.ac.jp/j/
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Receiver受
信 機 noise
雑 音temperature
温 度 (K) (K)

1200
1000
800

National
Astronomical
Observatory, Japan（Nb)
国立天文台
(Nb)
National
Radio
Astronomy
米国国立電波天文台 (Nb) Observatory, USA（Nb)
Instituteof Radio Astronomy at(Nb)Millimeter（Nb)
仏国ミリ波電波天文学研究所
Wavelengths,
France（Nb)オランダ宇宙研究所(Nb)
Netherlands
Institute(NbTiN)
for Space Research（NbTiN)
オランダ宇宙研究所
California
Institute of Technology
カリフォルニア工科大(NbTiN) （NbTiN)
Schottkydiode mixer（NbTiN)
国立天文台/情通機構(NbTiN)

600
400

ショットキー
ダイオード
ミキサー

200
0
0

Band 10バンド10

934 5 6

200

7

8

400

3hf/kB

600

800

1000

LO
frequency (GHz)
LO周波数
(GHz)
Fig. 2 ALMA noise specifications (blue line) and its actual performance demonstrated (red circle)

Credit: ALMA (ESO/NAOJ/NRAO)

Fig. 3 Spectrum (above) and phase (below) captured from Orion KL

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Feature Article: Forum on Superconductivity Technology Trends 2014
- Exploring Novel Superconducting Materials
Junichi Shimoyama, Associate Professor
Department of Applied Chemistry
School of Engineering, The University of TokyoA desire to explore novel superconducting materials has always been at the forefront of the research
agenda throughout the more than 100-year history of superconductivity, which began with mercury. The
trend continues into today, passing through several periods of research fevers. World records of criticaltemperatures (Tc) have been continually broken, first by elements followed by metal carbides, nitrides,
alloys, intermetallic compounds, and finally copper oxides. Currently, at atmospheric pressure the highest Tc
is 138K, while a zero resistance measured at a maximum of 153K has been realized under higher
pressures. Figure 1 shows the transition of critical temperature of superconductors. Initial studies focusedon whether superconductivity could be realized by cooling existing elements and alloys. Attempts graduallyshifted towards intentionally fabricating materials exhibiting similar structures and compositions, i.e. newmaterials were fabricated in order to explore novel superconductors.
A report by Hardy and Hulm
published in 1953 1), listed 30 typesof silicon and germanium alloys thatwere fabricated. Amongst these,eight compounds demonstrated
superconductivity,
reportingamaximum Tc of 17 K achieved in
V3Si, a record at that time. However,soon after an A15-type V3Si crystal
structure gathered attention, wherea measured Tc=18 K was observedin Nb3Sn 2). Thus, superconductor
research fever entered a phaseinvestigating A15-type intermetallic
compounds. A series of copperoxide-based superconductors werediscovered consecutively from 1986
Fig. 1 The transition of critical temperature (Tc) of superconductors
onwards. Here, all materials
exhibited new chemical compositions and crystal structures apart from La2CuO4 doped with alkaline earth
metals. Figure 1 shows that a rapid increase in world-breaking Tc’s coincided with the research fever ofcopper oxide superconductors. In particular, the Tc record was enhanced more than 50 K by YBa2Cu3Oy,
and its Tc value 92 K exceeded the boiling point of liquid nitrogen (77 K). It was during this period that theterm “high-temperature superconductivity” was established. This remarkable increase in Tc exceeded thepredictions of many researches at that time and was questionable soon after the initial press releases.
However, within one month, a 90K-class high Tc emerged worldwide and this led to consecutive discoveries
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Superconductivity Web21
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of superconductors in related material systems.
Superconductivity in MgB2 was realized in 2001, which was an already known and commercially available
material. Since 2008, many new breeds of iron-based superconductors were consecutively discovered.
Even now, discoveries of new superconductors are being reported. Although Tc’s of 39 K and 55 K for MgB2
and in iron-based superconductors, respectively are not very high, these superconductors are anticipatedas potential superconducting materials without requiring liquid He for cooling.
Although superconductivity has such a long history, there is no royal load to discoveries of novel
superconducting materials. A very large number of fabricated material systems unintended forsuperconductivity and unexpected material choices have unpredictably demonstrated superconductivity. It
is assumed that the theory behind the superconductivity phenomenon was almost been established.
However, it was barely utilized for exploring novel superconducting materials. Thus, currently, we cannot
make even low-level predictions as to whether novel material selections will demonstrate superconductivity
or not, and what the measured Tc will be. In other words, in a similar fashion to the exploration of novel
superconducting materials undertaken 100 years ago, an element of joy (dream) like “we don't know
anything until we try!” still remains today. Of course, nothing is strange if room temperature superconductors(superconductor exhibiting Tc at around room temperature) is coincidentally discovered somewhere in theworld today. Even if room temperature superconductors were to be discovered, this will probably not be asuperconducting material that can be practically used at room temperature. A superconductor available atroom temperature is truly a high temperature superconductor.
Reference:
1) G.F. Hardy and J.K. Hulm, Phys. Rev. 89 (1953) 884.
2) B.T. Matthias, T.H. Geballe, S. Geller, and E. Corenzwit, Phys. Rev. 95 (1954) 1435.

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Date of Issue: October 15

Superconductivity Web21
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KSP, Kawasaki, Kanagawa 213-0012 Japan Tel:+81-44-850-1612, Fax:+81-44-850-1613

Feature Article: Forum on Superconductivity Technology Trends 2014
- High Field Magnets
Satoshi Awaji, Associate Professor
High Field Laboratory for Superconducting Materials
Institute for Materials Research, Tohoku University
The commercialization of high temperature superconducting wires has led to the worldwide development
and progression of superconducting device applications utilizing such wires. Specifically, rare earth hightemperature superconducting, REBa2Cu3Oy (RE123) coated conductors exhibit superior mechanical andhigh in-field critical current density characteristics. Since its conception, an expectation towards high fieldmagnet applications has remained high on the research agenda. Currently, the National High Magnetic
Field Laboratory (NHMFL) in the USA is progressively developing a 32 T-superconducting magnet, and isbeing followed by worldwide developments of high field superconducting magnets 1). On the other hand,challenges associated with tape-shaped high temperature superconducting materials with high criticaltemperature characteristics have been raised, having issues that were not apparent in conventional
materials. Problems included burnout caused by hotspots, and degradation attributed to the delamination ofRE123 multilayers. Several methods designed to resolve these issues have been proposed and therealization of high temperature superconducting high field magnets is anticipated. In this article the author
highlights several major developments of high temperature superconducting high-field magnets, inparticular the development of cryogen-free, 25 T superconducting magnets and the proposed 50 T hybrid
magnet, which have also been led by the Institute for Materials Research, Tohoku University.
Figure 1 shows the magnetic field generated by liquid helium cooled superconducting magnets (SM) andcryogen-free superconducting magnets (CSM) which have been developed since 1990. The material
names as shown in the Figure are for the innermost coil. Since 2000 onwards, a change ofsuperconducting materials from metalic superconductors to high temperature superconductors is clearlyobserved. As of 2014, the maximum magnetic fields generated by superconducting magnets stand at 24 T
and 20 T for helium cooling and cryogen-free, respectively. The symbols in the brackets of the figure relate
to the test results using compact coils, performed in a water-cooled copper magnet back-up field (19 T or 31
T) at NHMFL. A maximum magnetic field of 35 T has been successfully realized in these tests. It has beenreported that the high performance characteristics of high temperature superconducting materials has
finally been demonstrated, although they are not a whole superconducting magnet. High temperature
superconducting materials therefore have to be capable of generating magnetic fields greater than 35 T. A
25 T cryogen-free superconducting magnet developed at the Institute for Materials Research, Tohoku
University, and a 32 T superconducting magnet developed at the NHMFL consist of outer NbTi and Nb3Sn
superconducting magnets and RE123 inner magnets. Both magnets are designed with a strong
electromagnetic stress of around 450MPa, using the advantage of the superior mechanical properties ofRE123.

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Superconductivity Web21
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KSP, Kawasaki, Kanagawa 213-0012 Japan Tel:+81-44-850-1612, Fax:+81-44-850-1613

Fig. 1 The transition in the magnetic fields generated by liquid helium cooled magnets and cryogen-freesuperconducting magnets. White triangles indicate results from High Field Laboratory, Institute for Materials
Research, and the white circles relate to the results obtained by NIMS

Reference:
1) D. Markievicz et al., IEEE TAS 22 (2012) 4300704.
2) S. Awaji et al., IEEE TAS 24 (2014) 4302005.

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October 2014

Date of Issue: October 15

Superconductivity Web21
Published by International Superconductivity Technology Center
KSP, Kawasaki, Kanagawa 213-0012 Japan Tel:+81-44-850-1612, Fax:+81-44-850-1613

Feature Article: Forum on Superconductivity Technology Trends 2014
- Overview of Projects Undertaken Worldwide
Yutaka Yamada, Principal Research Fellow
SRL/ISTEC
The research and development field has accelerated with globalization and it has become vital tounderstand worldwide trends and the efforts of each county. Every year, ISTEC hosts the International
Symposium on Superconductivity and actively supports the International Superconductivity Industry
Summit. Leading researchers form around the world working in the superconductivity field provided an
overview of country trends, which were published last year in ISTEC’s on-line journal “Superconductivity
Web21”. Additional information allowed the editing office to publish “Current worldwide projects” in an easy
to understand table format 1) (table below). Each member corporate, institution and other researchers haveeffectively utilized this information for their R&D activities as well as preparing their project-planning drafts.
In this article, the author introduces major worldwide projects. The projects conducted in Japan were
excluded on this occasion since these were introduced in other lectures.
The following provides an overview of the major projects conducted by each country:
EU: EUROTAPES-Pj (wire development) was launched involving many research institutions. However,wire characteristics such as length and Ic are not comparable to past records set by Japan and USA. On
the other hand, the world’s longest 1km-class high-temperature superconducting cable (AmpaCity-Pj:
Essen, Germany) has entered the final stage (final year 2016). There are four ongoing research studies
focusing on wind power applications (amongst these, only Hydornenie Pj of GE has completed. Others asshown in the table), Suprapower Pj employs low cost MgB2 wires. Columbus Superconductors, a leading
superconducting wire venture based in Italy, has a significant presence.
USA: Similar to Europe, investigations focusing on wind power applications have increased. MgB2 can beeasily fabricated into long wires, and investigations of potential equipment applications utilizing these wires
have begun. Coiling development for high-field applications have launched in Florida. The author considers
that this could be the first large-scale coil employing YBCO coated conductors, similar to a coil developedby Tohoku University. The investigations have been aiming for the design of a practical system, able to copewith electromagnetic forces as well as having quench protection. Further information is expected for the
future development of large-scale coils.
Korea: Whilst conventional wire development Pj (DAPAS) has concluded, demonstration projects (AD, DC
cables) for renewable energy applications, including wind power and photovoltaic power generation are
now being advanced under JEJU-Pj.
Russia: Superconductivity development has intensified recently. Demonstrations of the world’s longest
2.5km cables have taken place in St. Petersburg, as well as wire development projects advancing under
the Superconducting Industry Project, together with other developments undertaken at other institutions.
October, 2014

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October 2014

Date of Issue: October 15

Superconductivity Web21
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KSP, Kawasaki, Kanagawa 213-0012 Japan Tel:+81-44-850-1612, Fax:+81-44-850-1613

ROSATOM and the Federal Grid Company have led the trials. Russia has a strong interest in energy froma national characteristic viewpoint.
China did not participate at ISIS2013, and thus latest information is not available. Using 2012 data
published in Web21, the author selectively highlights the topics.
Reference:1) http://www.istec.or.jp/web21/pdf/14_03/all.pdf （ISTEC Web21 March, 2014 issue）

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Note:

EU

Country

Current Limiter

ECCOFLOW Pj

Wind Generator

Wind Generator

Wind Generator

DC Cable

Suprapower Pj

INNWIND.EU Pj

HTS-Geno Pj

DC Cable Pj*

Institutes involved

9kV/15.6

in designing of 10MWmachine（Weightover 10MW HTS Generator without

tecnalia, Acciona, Columbus, Oerlikon-

RES, a2a Reti Elettriche

Nexans, KIT, Siemens

Nexans

9 countries ）tested at 1.5-15kA, 150-500kV

R&D

kA-class cable

Winding technique for large Coil and othersystemーYBCO large field winding and test

off-shore windmill

10-20MW machine, high efficiency, for

Nexans

KIT, Siemens

Institutes

Siemens、Suzlon、Gamesa、DTUほか27

Gear system, MgB2, Cooling R&D (KIT) 30%reduction, efficiency more than 95%) Leybold, Univ. of Southampton, KIT

Success of 2-year Operation (Bi).

UpgradeOperation started in Essen (2014)12 kV/4.6 MVA, 2-year Operation and

1km 3 phase cable (Bi)

10kV/2.3kA class FCL (Y), 10kV/2.3kA-

24kV/1kA class FCL completed in 2012

FCL in a real grid planned (2013)
End. Now for preparing(2012) Resistive FCL set in substation.

16.5kV/1kA class、24kV/1KA class, Y-

12kV/800A class (2011)、12kV/1kA class

200m-250A（BRUKER）

National Institute, 1 Technical Center inothers

Theva….(8 companies, 6 Universities, 5

20 Institutes such as Bruker, Nexans,

Contents

cost of 100€/kAm, round wire andStarted in 2012

Status (- unknown)

and Processes: length of 500m, theABAD, RABiTS Substrates, YBCO Wire

Summary of Target

Here only posted the EU part while you can see other area's projects in Aian, US, Korea and China.

Current Limiter

Italian RSE/a2a Pj*

LimiterCable, Current

Wire (Y)EUROTAPES Pj

AmpaCity Pj

Devices, Wire

official name)

Project (Pj) Name (*notWorld Project at a Glance (as of 2014 August)ー€4M, 2011-2014€ 13.8M, 2012-2017

2012Dec-2016

2012-2014+2011-2015

ー€20M, since 2012.9 with 54 month

Budget, Term, other data (- unknown)

ISIS201３

ISIS201３

ISIS201３

ISIS2013

2013 Milan

ASC2014, Exco

ISIS2013

ASC2014,

ISIS2013

s.eu/

http://eurotape

ISS2013references/origin

October 2014
Date of Issue: October 15

Superconductivity Web21

Published by International Superconductivity Technology Center
KSP, Kawasaki, Kanagawa 213-0012 Japan Tel:+81-44-850-1612, Fax:+81-44-850-1613-20-