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C
Contentss:

Topics:ew in the Woorld of Supeerconductivityy- What’s Ne
Feature Arrticle: The 26
2 th Internattional Symp
posium on Supercondu
S
uctivity (ISSS2013)-SPL/PL Le
ectures-Physics an
nd Chemistryy (incl. Vortexx Physics)-Wires, Tap
pes and Cha
aracterizatio n-Films and Junctions/E
Electronic De
evices-Large-Sca
ale System Applications
A

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CE
httpp://ringring-keirin.jp

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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►Electronics

엘렉트로닉스

电子应用 [diànzǐyè yìngyòng]Superconducting Spintronics for Next-generation Computing
University of Cambridge (January 15, 2014)
Researchers at the University of Cambridge have announced a breakthrough in the field of spintronics—a
new technology that could become the basis for a future revolution in computing. The researchers haveprovided the first evidence suggesting that superconductors could be used as an energy-efficient source for“spin-based” devices, which have already begun to appear in microelectronics circuits. Previously,
superconductors and spintronics were thought to be incompatible. The new study, however, has shown thatthe natural spin of electrons can be manipulated—and detected—within the current flowing from a

April, 2014

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superconductor. To enable both superconductivity and the manipulation of electron spin simultaneously, theresearchers added an intervening magnetic layer composed of the rare earth holmium. Within this later, themagnetism rotates and forms a non-collinear interface with magnetic permalloy layers, which are used tomanipulate spin. As Cooper pairs pass through this rotating magnetic layer, the pairing is preserved despite
the fact that one electron is effectively “flipped” to create parallel-aligned spins. The researchers
successfully detected such parallel-spin Cooper pairs, confirming their existence. Dr. Niladri Banerjee of theMaterials Science Department commented, “What’s never been directly demonstrated until now is that
Cooper pairs can serve as transmitters of spin. That’s an important step forward since now it is clear thatsuperconductivity can play a key role in spintronics.” The study results could pave the way for the use of
superconductors in spintronics, making such devices much more energy-efficient. The group’s work has
been published in Nature Communications. As a next step, the group plans to create a prototype memory
element based on superconducting spin currents and to search for new material combinations capable ofincreasing the effectiveness of their method.
Source: “Superconducting spintronics pave way for next-generation computing”
University of Cambridge press release (January 15, 2014)
URL:
http://www.cam.ac.uk/research/news/superconducting-spintronics-pave-way-for-next-generation-computing(This work is licensed under a Creative Commons.)
Contact: Tom Kirk, tdk25@cam.ac.uk►Basics기초 基础[jīchǔ]Secrets of Superconductivity
Los Alamos National Laboratory (January 3, 2014)
Two separate studies involving researchers from the Los Alamos National Laboratory have produced new
findings regarding the relation between superconductivity and magnetism. Superconductivity andmagnetism are often considered as rivals, since the electrons in superconductors form freely moving pairsthat conduct electrical current with no resistance while magnetic electrons lock themselves into a rigid
arrangement that does not move. However, the two above-mentioned studies have shown that theelectrons in Cerium-Cobalt-Indium5 (CeCoIn5) are simultaneously both superconducting and magnetic. In
an experiment conducted at the Paul Scherrer Institute (PSI), researchers observed an entirely new form ofsuperconductivity in which electrons form pairs with clockwise and counterclockwise spins as well as pairs
with spins in the same direction. In the latter situation, the superconductivity only appeared when theelectrons were both superconducting and magnetic. Furthermore, the ordered arrangement of themagnetic electrons could be manipulated by modifying the direction of the applied magnetic field. Michel
Kenzelmann, the leader of the PSI research team, commented, ““The observed behavior of the material
was completely unexpected and is certainly not a purely magnetic effect. This is a clear indication that in thematerial the new superconducting state occurs together with the spin density wave.” These findings
suggest the possibility that the quantum state of electrons, which is linked to superconductivity, might be
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directly controllable, an ability that could have important implications for future quantum computers.
In the second study, small amounts of impurities were introduced into CeCoIn5; unexpectedly, these
impurities caused the superconducting electrons to form nano-droplets of magnetic order. When theamount of impurities was increased, the droplets grew and eventually overlapped, causing the entire
material to become magnetic. The application of pressure to the magnetic material globally reversed theeffect of the impurities, causing the material to become superconducting once again. Using a techniques
similar to magnetic resonance imaging, however, the researchers found that the nano-droplets of magnetic
order actually persisted but were hidden by the superconductivity.
Combined, these studies show that the electrons in CeCoIn5 are more adaptable than previously believed.
Joe Thompson, a collaborator in both studies, commented, “Superconductivity continues to give new
surprises. As its secrets are revealed, we learn more about the quantum world of electrons and can begin to
imagine new ways to use them for future technologies. Superconductivity in Cerium-Colbalt-Indium5,
discovered nearly a decade ago at Los Alamos, may be the Rosetta Stone that many of us have been
looking for.” Both of the studies were published in the same online issue of Nature Physics.
Source: “Secrets of Superconductivity Revealed”
Los Alamos National Laboratory press release (January 3, 2014)
URL: http://www.lanl.gov/newsroom/news-stories/2014/January/superconductivity-and-magnetism.php
Contact: Nancy Ambrosiano of Communications Office, nwa@lanl.gov

Quest for Better Superconducting Materials
Oak Ridge National Laboratory (January 27, 2014)
In a recent study published in Physical Review Letters, researchers at the Oak Ridge National Laboratory
examined the essential roles of chemical dopants in the creation of high-temperature superconductors.
Dopants introduce non-uniformity and disorder to the crystal structure of a material. By understanding how
chemical dopants alter the behaviors of pre-doped materials, scientists hope to become able to design
superconductors that function at higher temperatures. The lead author of the paper, Krzysztof Gofryk,commented, "Through this work, we have created a framework that allows us to understand the interplay ofsuperconductivity and inhomogeneity. Thus, for the first time, we have a clearer picture of the side effects of
dopants." The team leader, Athena Safa-Sefat, added, "Our bulk and atomic-scale measurements on aniron-based superconductor have revealed that strong superconductivity comes from highly doped regionsin the crystal where dopants are clustered. If we can design a crystal where such clusters join in an
organized manner, we can potentially produce a much higher performance superconductor."

Source: “ORNL study advances quest for better superconducting materials”
Oak Ridge National Laboratory press release (January 27, 2014)
URL:
http://www.ornl.gov/ornl/news/news-releases/2014/ornl-study-advances-quest-for-better-superconductingmaterials
Contact: wallira@ornl.gov
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tFeaturre Article
e: The 26th
Internaational Sy
ymposiumm on Sup
percondu
uctivity(ISS20013)-SPL/P
PL Lectures

Tanabe, Yutakka Yamada, Kota
K Katayam
maKeiichi T
ISTEC
3 hosted a sp
pecial plenarry lecture fromm each categgory of power equipment applications and MRI.
ISS 2013
The pleenary lecture
es comprised
d of Fe-bassed superco
onductors, SFQs,
S
Japann’s and US
SA’s wiredevelopm
ment sectors and an upda
ate on the currrent status off the cable deemonstration project in Jap
pan.
Special plenary lectture 1, Dr. B.P.
B Strauss, US Departm
ment of Enerrgy (DOE) “R
R&D FOR TH
HE NEXTGENERAATION OF SUPERCONDS
DUTING MAGGNETS”
Looking back at wire and coiling teechnology
developm
ments since the discovery
ry of superco
onductivity,
Dr. Strau
uss from the DOE,
D
throughh his long ten
nure at the
National Laboratoriess and the DO
OE, highlighted
d potential
ues that couldd arise in the future. He coommented
HTS issu
that althoough 95% off supercondu
ucting wires hhave been
employeed for magne
et applications, the develo
opment ofprincipal technologiess ceased during the 80s aand that nont progress has occurrred since tthen. For
significanexamplee, concerns associatedawitth ultra-thin fifilamentary
Dr. B.P. Strrauss (DOE)
wires, twwisting wire filaments annd stabilizatio
on issues
were raised. The US
SA recently published a report on high-fieldhsupperconductingg magnet ap
pplications
ed to be a ¥100billion¥
woorldwide market, inclusiv
ve of accelerrator applicattions). He weent on to(assumeemphasize that in ord
der for HTS too penetrate fu
urther in the marketmincorpoorating the abbove-mention
ned areas,
ecessary for cablecand wiree engineeringg standards in
ncluding “lenggth, homogenneity, strength, stability,
it was neloss, insu
ulating strenggth” to satisfy certain criteriia required byy users. It wass his opinion that the establishmentof these ffactors wouldd be desired tot realize regu
ular viable sa
ales.

Special plenary lectture 2, Dr. J.
J Clarke, Un
niversity ofCaliforniaa“ULTRA
RALOW
FIELD
F
MA
AGNETICRESONA
ANCE IMAGING”
employed forr clinical use, currently reeaching 30
MRI is e
thousandd-units worldw
wide in a ma
arket valued at around¥200milliion. Mainstre
eam systems have evo
olved from
1.5T to 3T. With th
he higher magneticmfield
ds offering
MRI sensitivitties, ultra-low
w field MRIs (ULFMRI)
greater M
Prof. J. Clarke (Univversity of Califo
ornia)
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employ a gradiometer utilizing a su
uperconductinng SQUID en
nabling 100 μT
μ applicationns.
sand future prospeccts of these innovative
Dr. Clarkke, a pioneerr of SQUID, lectured on tthe current status
ultra-low--field MRI technologies. Ultra-low-fieldU
d MRIs emplloys a gradio
ometer that uutilizes SQUID sensor
allowing nuclear mag
gnetic resona
ance imaging
g to be done
e at low magnetic fields eequivalent to terrestrial
owever, spatiial resolutions
s are currentlly inferior com
mpared tomagnetissm. This realizes compact systems, ho
high-fieldd MRI system
ms. Despite this, advantaageous attrib
butes remain including thee ability to distinguishdbetween cancerous cellscby deterrmining differe
ences in the longitudinal magneticmrelaaxation time (T( 1) of theging data froom different elementseof thet brain perrformed by measuringmcells. The lecture intrroduced imag
uture prospec
cts to improvve image-pro
ocessing timees, which arre currently significantsdifferencces in T1. Fu
issues, w
were also pressented. Also,, Dr. Clarke ccommented th
hat systems costsccould bbe significantly
y reduced
since hig
gh-field superc
rconducting coils would noot be utilized.

Plenary lecture 1,
1 Professo
or Kitaoka, Osaka
Universitty
ON“RECENNTTOPICSH
HIGH-TC
SUPERCCONDUCTIV
VITY IN CUPRATES AND
PNICTID
DES”
or Kitaoka fro
om Osaka Un
niversity, repo
orted onProfesso
the micrroscopic elecctron states of copper-ba
ased orFe-basedd high tem
mperature su
uperconducto
ors. He
Prrof. Kitaoka (OOsaka Univers
sity)clarified tthat for copp
per-oxide supperconductorss, the hole(electronn) density annd supercond
ductivity-antife
erromagnetissm (AFM) phhase diagram
m could be explainedusing a tt-J model, em
mphasizing spinsfluctuatio
ons as a promising candidate for the origin of the attractive
interactio
on of the Coo
oper pairs. For Fe-based superconduc
ctors the sha
ape of the Feermi surface holds the
key. Thee change inn shape of the Fermi ssurface stren
ngthens spin fluctuationss, which pro
oduce thesuperconnducting phasse. It was also reported th
hat the increas
se of Tc from 28 K to 50 K in the La1111-systemoccurredd due to changing nesting conditions tha
at led to Fermmi surface recconstructionss.

Plenary lecture 2, Drr. Izumi, ISTE
EC-SRL“ACHIEV
VEMENTS IN M-PACC
C PROJECT
T AND
FUTUREE PROSPECCTS ON R&D
R
OF C
COATEDCONDUCTORS”
mi from ISTEC
C-SRL, lectured on the reresearch
Dr. Izum
outcomees and future
e prospects ofo wire devellopment
undertakken as part of the NEDO project entitled“Technollogy
Deve
elopment
m-basedof
Yttrium
Dr. Izumi ( IISTEC-SRL)
Superconducting Pow
wer Equipment”, which cooncluded
ast year. The past five years has seen aan improvem
ment in the Ic characteristics
cs and lengths
s of wires.
March laIn particu
ular, improve
ements of in--field charactteristics, inclu
uding long wireswand demmonstrations involving
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multifilam
ment wires along with furrther reductio
ons in lossess are anticipa
ated to realizze an array of further
applicatio
ons. Also intrroduced was a 5-yr proje
ect launched last year entitled “Develoopment of HT
TS CoilingTechnoloogy”. The aims of the projectp
are too develop wire
w and coilling methodoologies for MRIs
M
andHeavy-Ioon Medical Acccelerators. A particular ta
arget of the project is the likelihood of rerealizing the fabricationfof a 200--m long wire at 600 A (65 K, 3 T), 1000
0 A (35 K, 10
0 T). It is antic
cipated that fu
future outcom
mes of thisproject w
will contributee to Japan’s and the wid
der internatio
onal commun
nities where ddemand for high-tech
medical-use equipme
ent are increa
asing in the fu
uture.

Plenary lecture 3, Dr. D.S. Holmes,H
Boooz Allen
Hamiltonn“SFQ COOMPUTING IN
I THE USA””
mes of Boozz Allen Hamilton, introducced theDr. Holm
current ddevelopmenttal status off SFQ (Singgle Flux
Quantumm) computing technolog
gy in USA. Powervolumes consumed at
a a new largge-scale dataa centerdly increasing. Computinng technologiies withare rapid
Dr. D..S. Holmes ( B
Booz Allen Ha
amilton)process capabilities exceedingeexxa-scales (exxa=1018)
be realized wiithout significcantly reducinng power con
nsumptions. SFQs
S
are pottential candid
dates ablecannot b
to addreess and solvve this issuee. A new ciircuit that ra
adically reduc
ces the pow
wer consume
ed at theconventio
onal SFQ ga
ate has beenn developed and progres
ssed in the USA.
U
A 3-yeaar IARPA prooject wasrecently llaunched withh SFQ computing memory
ry developme
ent as a top prriority.

Plenary lecture 4,
4 Professor Nakamuraa, TheUniversitty of Tokyo“PROGR
RESS
O
ONSUPERCONDUUCTINGQUANTUUM CIRCUIT
TS”
Professoor Nakamuraa from The UniversityU
off Tokyo,
lectured on the prog
gress made in superconnducting
m circuit tecchnology aiimed for q
quantumquantum
computinng. Specifically, the desig
gn improveme
ent of asuperconnducting qua
antum bit andacontrolling theProf. Nakamura (Thee University off Tokyo)
electrommagnetic mode by couplingg to a resona
ator wased. Materials engineering has remarka
ably prolonged
d the coheren
nce time, the greatest techhnologicalhighlighte
issue, fro
om initial 1 nss to 100 μsec,, producing lo
ow error rate gate operatio
ons.

Plenary lecture 5, Prrofessor V. Se
m, University
elvamanickam
y of Houston“STATUSS OF COATE
ED CONDUCCTOR AND HHTS DEVICEE PROJECTSS IN USA”

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2, Fax:+81-44-8850-1613

Professoor V. Selvam
manickam froom the Unive
ersity of
Houston reported reccent researchh findings of Y
Y-based
A. Wirecoated conductors developed in the USA
ment was orriginally spea
arheaded byy AMSC
developm
and SuuperPower, but now STIS
has join
ned in.
Applicatio
ons of intere
est presented
d at the sym
mposium
included Y-based hig
gh-field coilin
ng developedd by theaboratory in Florida,
National High Magnetic Field La
net developed by BN
NL andHTS 4--pole magn
Conducto
or-on-Round-Core (COR
RC) cables prroduced
by Adva
anced Condu
uctor Tech. LLC. CORC
C cableshave alre
ready demon
nstrated 6000
0 A at 4.2 K
K, 19 T,
which seeem promising for nuclear fusion appliccations.

Prof. V.Selva
vamanickam(University oof Houston)

Plenary lecture 6, Dr.
D Honjo, To
okyo Electricc Power
Companny“HIGH TEMPERATTURE SUPERCONDUUCTINGDEMONSTRRATION PROOJECT IN JAP
PAN”
CABLE D
Dr. Honnjo from To
okyo Electricc Power Co
ompanyreported on Bi-basedd superconducting cables that are
onstrated at thhe Yokohamma Asahi
currentlyy being demo
on. These tria
als are first off a kind in Jap
pan with
Substatio
the cable
e connected tot the actual grid, and theere haveDr. Honjo (Tokyo Elecctric Power Co
ompany)been no operational issues
i
assoc
ciated with coooling or
he track reco
ord so far deemonstrated thet remarkabble reliability for future
current ttransmission reported. Th
superconnductors ope
erating in pow
wer utility app
plications. It was
w clear fromm the argum
ments set out by Honjo
that curre
ent cables in Japan have already passsed 20-40 yeears since theeir installation, and a perio
od for theirreplacem
ment was imm
minent. If a su
uperconductiing cable cann be installed in existing ccable ducts withoutw
theneed for new location
ns and additio
onal land, thiis will be a great opportun
nity for the siignificant effe
ectivenesse realized.
afforded by superconductivity to beerconductivity
y Web21
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uctivity Technology Center
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Featurre Article: The 26th Internation
nal Symp
posium onn Superco
onductivityy(ISS20013)-Physiics and Ch
hemistry (incl.
(
Vorte
tex Physic
cs)
Atsutaka Maeda, Professsor
ent of Basic Scciences,
Departme
Graduatee School of Artss and Sciencess, The Universsity of Tokyo

Snapsshot of the session

S program committeecin charge off the physics and chem
mistry sectionns has orga
anized a
The ISS
dedicate
ed session on specific themest
for thhe past coupple of years, withw invited leecturers selected toaddress the themes. Their aim
ms at the IS S are to fac
cilitate fruitful discussioons on the progresspstry conduc
cted over thee past yearr within aof superrconductivitty research on physics and chemis
relativelly short 1.5 - 2 days. BelowB
is a b rief summarry of the Phy
ysics and Cheemistry sesssion at theISS20133.
ar’s themes focusedfon: 1) new supeerconducting materials; 2)2 the currennt status of thheoretical
This yea
researchh; 3) iron-cha
alcogenide su
uperconductoors, and 4) spectroscopiic experimennts (STM in particular).
p
Apart frrom these thhemes, on the first day of the symp
posium, a pleenary lecturee delivered byy Kitaoka(Osaka University), reported thee overall relaationship of antiferromag
gnetic fluctuaations, Fermmi surface
o coppernesting and structural parameters, focusing particularlly on the critical tempeerature Tc ofe-based supeerconductors
s. Regarding theme 1) ne
ew materials, Japan’s ressearch activities in thisoxide/Fearea weere prominen
nt as all five invited lectu
urers were frrom Japan despitedthis bbeing an inte
ernational
symposium. The coontents of th
he lectures in
ncluded: (Caa,La)Fe2As2 (Tc =45 K) by Kudo (OOkayamaK by Yajima (The Institu
ute for Solid State Physiccs, The University of
Universitty); BaTi2Bi2O (Tc=4.6 K)
Tokyo); BiS2-based supercondu
uctor (Tc=10
0.6 K) by Mizuguchi (Tokyo Metrropolitan Un
niversity);zero
HgBa2Caa2Cu3O8 (TTc=153 K)
K by Takeshita (AIST); Alkali meta
al intercalateed iron-chalcogenide
superconnductors (Tc=45= K) by Ha
atakeda (Tohhoku Univers
sity; selectedd from contrributed papers), andApril, 20114© ISTEC 20 14 All rights reeserved.

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the world’s first hole-doped superconductor with the so-called T’-structure copper-oxide superconductor
by Takamatsu (Tohoku University). Regarding theme 2) theoretical research, several theories basedon different standpoints were presented, which, however all failed to form any consensus –Casula (CNRS); Capone (CNR-IOM); Ku (Brookhaven). Concerning theme 3), Iron-chalcogenide
superconductors, have recently attracted considerable attention as potentially very high Tc
materials, since higher Tc’s have been consecutively reported in the 122-structure, intercalated
system, mono-layer film, etc. In fact, Xue (National Tsing Hua University), introduced their research on
mono-layer films during the last ISS. Also in ISS2013, the enhancement of Tc by theabove-mentioned intercalation research and the introduction of local strains induced in high quality
epitaxial thin films – Nabeshima (The University of Tokyo; selected from contributed papers), attracted
the attention of the audience. In the spectroscopy session, 4), high–quality data were presented by
Nishida (Tokyo Institute of Technology → Toyota Physical and Chemical Research Institute) and
Suderow (Autonomous University of Madrid), which accentuated the high quality STM researchundertaken worldwide. In particular, both groups have succeeded in observing vortex motion. Other
lecturers included, Eskildsen (University of Notre Dame) on small-angle neutron scattering experiments;
Roditchev (INSP) and Kato (Osaka Prefecture University), both presenting their theoretical research on
the vortex phase diagram and the vortex state of nano-sized superconductors.

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Feature Article: The 26th International Symposium on Superconductivity(ISS2013)-Wires, Tapes and Characterization
Teruo Izumi, Director
Masateru Yoshizumi, Associate Director
Division of Superconducting Tapes, Wires, and Power Application
ISTEC-SRL
The session comprised of 29 presentations and around 40 posters. This article summarizes several
selected presentations along with a synopsis of a related plenary lecture presentation.
The plenary lecture was held on the first day of the symposium, where Professor Selvamanickam from the
University of Houston highlighted Y-based wire development and related power device research ongoing in
the USA. Y-based wire development has realized the fabrication of 100m-long wires at 1m/450A at STI,
and is now being prepared to produce 1km-long wires. The University of Houston has focused onenhancing the in-field characteristics of MOCVD wires. The latest reported data confirms high in-fieldcharacteristics (2172A/12mm@30K,3T) with 25% Zr additions. The resulting characteristics are 6.4-times
greater than those targeted by the ARPA-E project, which were aimed at enhancing the characteristics by
4-times. In particular, the observation confirmed that the ab-surface was doped when the doping volume
increased above a certain value. For power device development, 15.7 T was confirmed using a 16 T demo
HTS magnet. Additionally, SMES (ARPA-E), smart grid (equipped with SFCL), cable for SMES, helium
gas-cooled cable and 1.5 T MRI utilizing BSCCO wires were also introduced.
At the wire session, held on the second day of the symposium, Dr. Miyatake (JASTEC) was the first
speaker of the day. NMR development was described, highlighting the essential factors required to realize
PC mode, which is a trade-off between superconducting connections and the degree of magnetization. It
was reported that these factors significantly benefited other essential field characteristics such as, fieldstrength, and n-value.
Professor Obradors introduced the research activities undertaken in Europe. Europe holds their highest Ic x
L value of 200m-250A, achieved by BRUKER, a record that has already been achieved by Japan and USA
more than five years ago. Although a variety of film deposition methods onto substrates have currently been
investigated, a firm decision has to be made sooner or later. It is the author’s perception that the only new
research studies reported from Europe pertained to low loss results for 120-filament short wires.
Dr. Oh (KERI) explained the developmental status in Korea. The following two projects have beenlaunched aimed at future materials development;
2013-20172013-2018

April, 2014

DC-Reactor, wire development
Materials development within KERI

1kA/cmAPC SmBCO© ISTEC 2014 All rights reserved.

$5M
$5M

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April 2014

Date of Issue
e: April 15

Supeercondductivvity Web21
W
1
Published by Internationa
al Supercondu
uctivity Technology Center
KSP, Ka
awasaki, Kanag
gawa 213-0012
2 Japan Tel:+81-44-850-1612
2, Fax:+81-44-8850-1613

It was reported that Dr.
D Moon at SuNAM led thee former proje
ect. Recent research topiccs presented by Korea
orming superc
rconducting connections.
cFurtherF
to thiss, the person in charge
Universitty included the results of fo
made a ffurther preseentation on the final day off the sympos
sium. Having etched the ssilver layer of the wires
made byy SuperPowe
er, a micro-ho
ole was punch
hed and layered face-to-fa
ace. This wennt through a short-timesheating p
process undeer low pressu
ure. After pro
ocessing, a 211 + Ba-Cu-O
O phase meelt was presen
nt. A long
period off heating in oxygenofollow
wed and produ
uced superco
onducting con
nnections witthout any detteriorationin its innitial characcteristics of 85 A. A ffinal transient processinng was deeemed necesssary forincongruent-system materialsmwhe
en fabricatingg connectionss utilizing a melt.
m Howeveer, their resullts did not
olved. The disclosuredof microstructu
ure of thedisclose the microstrructure and how this isssue was reso
g the E-J cha
aracteristics measuredmat lo
ow electric fieeld regions.
material is now expeccted, including
a from Fujikurra reported thheir recent deevelopments related to wirre fabrication.. Noteworthy was their
Dr. Iijima
successfful fabricationn of a 1km long wire ex
exhibiting rela
atively homog
geneous chaaracteristics. Tapestar
evaluatio
ons recorded approximate
ely 20% homoogeneity.
s
an impprovement off the in-field characteristic
cs necessaryy for the realization of
Recent yyears have seen
applicatioons for pracctical use. Th
he table sum
mmarizes the in-field da
ata characterristics reporte
ed at thesymposiu
um, realized by major ma
anufacturers and researc
ch institutions at the forefrront of wire fabricationfbased in Japan and USA.
U
In addittion to favora
able characteristics achiev
ved with shortrt-length wiress, data on
ength wires was
w only reporrted by Japan
n. This showss Japan’s supperior technollogical proweess.
longer-leComparison of measured in-field charaacteristics of Y-basedYcoatted conductorrs fabricated by major
Table Cw manufactures and resewire
earch institutiions in both JapanJ
and USSA

April, 20114© ISTEC 20 14 All rights reeserved.

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Date of Issue: April 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

An overall impression of the session proved Japan’s high level of technology developed under the M-PACC
project.

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April 2014

Date of Issue: April 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: The 26th International Symposium on Superconductivity(ISS2013)-Films and Junctions/Electronic Devices
Mutsuo Hidaka, Chief Senior Researcher
Nanoelectronics Research InstituteNational Institute of Advanced Industrial Science and Technology
The number of presentations at the Films, Junctions and Electronics Devices (FD) session was 59,
including both oral presentations and posters. Amongst these, 22 presentations were on films/junctions, 15
on SQUIDs, 12 on digital, 6 on detectors, 1 on quantum bits and 3 related to microwaves.
The Films and Junctions session was mainly focused on the fabrication methodology of Fe-based thin films.
Professor Naito from Tokyo University of Agriculture and Technology, highlighted two routes for F-doping
into SmFeAs(O,F) thin films. The first route involves a two-step process by first, depositing an SmF3 thin film
on SmFeAsO, followed by F diffusion into an SmFeAsO thin film, producing a Tcend = 56.4 K. The other is asingle-step route involving the supply of F from FeF2 during deposition, producing Tcend = 54.0 K. Professor
Holzapfel from IFW, Dresden, reported their successful deposition of high quality Fe-based Ba-112 and 11
heterostructure thin films.
The session related to SQUIDs was presented with an array of associated applications. Professor Clark
from UC Berkeley reported the developmental trends of ultra low-field MRIs utilizing SQUID detectors anddriven at 130 μT, which is at an equivalent level to terrestrial magnetism. The setup allows each component
to be resolved, for example, MRI-imaging of a human brain clearly resolved the cerebrospinal fluid andblood separately. Professor Enpuku from Kyushu University introduced a SQUID project undertaken under
JST’s S-Innovation program. One characteristic of this project was the SQUID, a common module
developed in joint collaborations and with each research institution employing the module for their own
application purposes. Professor Tanaka from Toyohashi University of Technology has developed a device
to detect foreign-metal bodies within lithium-ion batteries by utilizing high temperature superconducting
SQUID. He presented the potential detection of a foreign-metal body having 35 μm diameter, much smaller
than current technological limits of 100 μm diameter.
The session dedicated to digital applications amassed topics on low energy and multiplexing outputs fromdetection devices. Dr. S.Holmes, who leads the superconducting supercomputer project launched at the
beginning 2014 in USA, commented that there was a deadlock in reducing power consumption in CMOS
technology designed for 1 Exa-scale supercomputers, which exhibit 100-times the computation capabilities
of a K computer. It was established that only superconducting technology was able to realize lower power
consumptions and therefore the potential to break the deadlock. Dr. Yamashita, NICT, reported on
experiments undertaken to multiplex the output from superconducting single photon detectors (SSPD) by
utilizing SFQ circuits to bring out to room temperature with a line. The SFQ readout circuit integrates a
4-element SSPD array, producing the fundamental operation of a single output line. Further development of
this method showed potential to significantly reduce the number of output lines from a multi-pixel detector.

April, 2014

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Professor Yoshikawa from Yokohama National University presented a new type superconducting digital
circuit called an Adiabatic Quantum-Flux Parametron (A-QFP). A switching energy of 10 ZJ (1×10-20 J) was
confirmed by their experiments. This value is the world’s smallest logical element, three digits smaller
compared to that of a conventional single flux quantum (SFQ) circuit.
The trend is now towards multi-pixel detectors. Dr. Ukibe, AIST, introduced a materials analysis and mass
spectrometer systems that employed a 100-pixel superconducting tunnel junction (STJ). The material
analysis system successfully detected light element of N in SiC and effectively observed mass-separation
utilizing a signal with the same mass-to-charge ratio. Additionally, a significant reduction in measurement
time utilizing a 100-pixel STJ was confirmed. Professor Yamamoto from Nihon University reported on theexperimental study of Surface Plasmon Polaritons (SPPs) utilizing 50/50 beamsplitter. The Transition Edge
Sensor (TES) developed at AIST is the only device able to precisely count the number of SPP necessaryand has therefore been employed for this experiment.
Professor Nakamura from the University of Tokyo introduced recent progress in superconducting quantum
computers. One of the major issues with superconducting quantum bits is that the coherent times are too
short quantum calculations. Over the past ten years, investigations to disrupt the quantum states have been
performed, producing a 6-digit improvement in coherent time from an initial several-10 ps to several-10 μs.
The idea now in progress is to hybridize other types of quantum bits such as superconducting quantum bits
and spin by utilizing microwave and photonic interfaces.
At the microwave session, Dr. Du from CSIRO introduced microwave and terahertz applications employing
high temperature superconducting step-edge Josephson junctions. For microwave applications, a digitaldown-converter operating at 8~10 GHz incorporates an integrated Josephson mixer onto one chip. The
operation at a wide temperature range from 20~80 K was confirmed. Regarding terahertz applications, aterahertz imaging device operating at 600-GHz has demonstrated the clear observation of hidden materials,
which were not visible under light.

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April 2014

Date of Issue: April 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: The 26th International Symposium on Superconductivity(ISS2013)-Large-Scale System Applications
Yutaka Yamada, Senior Research Fellow
ISTEC-SRL
The session devoted to large-scale system applications had 31 presentations and 108 posters. Reports
were mainly based on YBCO coils with investigations pertaining to power applications such as cables andfault current limiters. With regards to cables, Furukawa Electric reported their results of current trials of acable in China whilst Fujikura reported their first findings of their cable demonstration test; (SA-1: STATUS
OF 275 kV REBCO HTS CABLE DEVELOPMENT IN THE NEDO PROJECT, S. Mukoyama, Furukawa
Electric, SA-3:DEVELOPMENT OF 66kV-5kA CLASS HTS POWER CABLE WITH IBAD/PLD REBCOTAPES, M. Daibo, Fujikura).
The symposium also addressed an exceptional issue from Okazaki, ISTEC, who was proposing wind-heat
power as potential a renewable energy source obtained by using superconducting heat generators. This
proposal does not generate power from conventional wind energy itself, but instead, the concept involves
the heat induced by revolutions of the wind turbine is stored, and subsequently the stored heat is used togenerate electricity using a steam turbine. Superconducting magnets generate induced current from therotary motion due to wind, producing the direct conversion of rotational energy to thermal energy andsubsequently storing the thermal energy. Power from wind can only be generated when it is windy, andtherefore the power generated is sporadic. The installation of more wind turbines requires greater control ofthe power output generated. In such cases, utilizing the stored energy for thermal power generation would
allow greater control of the power output. According to calculations made by Okazaki, this method looks
promising for the future allowing cheaper energy costs than compared to conventional battery-powered
applications.（SA-7:SUPERCONDUCTING HEAT GENERATOR FOR WIND HEAT POWER, T. Okazaki,
ISTEC）.
This year’s symposium had many presentations related to high temperature superconducting MRI and
NMR applications. Mine and his group at GE Global Research, reported their research results of an MRI
system employing MgB2 wires. A 10-inch bore coil at 3 T was fabricated and its initial n-value was small
between 3-4 and deemed impractical. This was modified to improve Ic homogeneity, which resulted in an
improvement of the n-value to around 20-26. The wire has a cross section of 0.7x3.1 mm, and has a
0.2mm-thick copper stabilizer layer. The 30cm-diamter coil applicable to MRI systems was fabricated.
Some 2 T (transmission current 300A) was generated at 14 K, therefore successfully causing excitation
without a large voltage. Although these demonstration trials were not performed in permanent-current mode,the only measured resistance of the coil voltage was (0.03 μΩ) generated due to the solder connection.
Investigations into superconducting connections were undertaken in parallel and a 10-11 ohm resistance
was recently recorded (the details was not published) (SA-10: DEVELOPMENT OF a 3 T-10-inch BORE
MgB2 MAGNET AT GE, S. Mine, GE Global Research).

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Yanagisawa from RIKEN introduced future prospects regarding high temperature superconducting NMR
originating from their recent research studies. Current NMR systems have been fabricated having amaximum 1GHz (23.5 T) by utilizing metal-based superconducting wires such as NbTi and Nb3Sn. Hightemperature superconducting REBCO, Bi2212, and Bi2223 wires demonstrated high critical current
densities even at high magnetic field of 20-40 T and at low temperatures of 4.2 K, potentially leading to
NMR systems with even greater magnetic fields between 2-3GHz. Additionally, it is possible at suchmagnetic fields that NMR system can be significantly reduced in size facilitating future ease of use. The
group at RIKEN actually fabricated and investigated a 500MH NMR (11.74 T) composed of low
temperature superconducting wires and REBCO wires. NMR systems conventionally require accuracies of
10-9/5mm (wire-width) for spatial homogeneity and 10-10/h precisions for temporal stabilization. (SA-11:
TOWARDS NEXT-GENERATION COMPACT HIGH FIELD NMR; THE WORLD’S FIRST LTS/REBCONMR MAGNET OPERATED AT 400 MHZ (9.4 T), Y. Yanagisawa, RIKEN) Many issues still remain forinvestigation in order to realize applications for practical use. There are therefore high expectations forJapan’s first project led by METI into investigation of high temperature superconducting medical equipment
applications.
Urayama from Kyoto University reported their current results from a 3 T MRI system (utilizing Bi-based coil)development. Soldering connections and a high-precision power source were employed in place ofsuperconducting connections. Realizing homogenous magnetic fields and stability at high levels of
precision in MRI systems have led to the acquisition of an actual human brain image. An important issue
reported during the presentation was coil burnout. A refrigerator cryocooled system experienced magnet
burnout during the third demagnetization process. It was when the cryo was opened that the burnout
between the coil turn terminals was confirmed. The reason behind the burnouts is currently underinvestigation and the results from these investigations are eagerly awaited since the majority of hightemperature superconducting applications utilize cryocoolers. The findings are thus important with regards
to future HTS applications. (SA-12: A CRYOGEN-FREE 3 T MRI SYSTEM FOR HUMAN BRAINRESEARCH USING Bi-2223 HIGH-TEMPERATURE SUPERCONDUCTING TAPES, S. Urayama, Kyoto
University)
There were a number of presentations from Korea reflecting their motivation in this area. For example,
Changwon University presented their investigations on wind power generator applications and reactors.
(SA-14: SUPERCONDUCTING POWER APPLICATION PROJECTS IN KOREA ESPECIALLYCONSIDERING THE RENEWABLE POWER ENERGY SOURCE, M. Park, Changwon University), as
well as recent studies on non-insulated HTS coils. （ SA-21: MECHANICAL AND ELECTRIC
CHARACTERISTICS OF VACUUM IMPREGNATED NO-INSULATION HTS COIL, S. Kim Changwon
University)
The presentations pertaining to the wire session were promising with regards to being applicable to both
MRI and NMR applications (connection resistance 10-17ohm, transmission current 26 A). The author
considered that combined with the results related to coiling, significant progress would be highly anticipatedfor industrial application of YBCO coils over the next couple of years.

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