Superconductor Science Research Articles

Stability of thermally bistable states and their switching in superconducting weak link

Superconducting weak link (WL), acting as a Josephson junction (JJ), is one of the widely used elements in superconductor science and quantum circuits. A hysteretic JJ with robust switching between its superconducting and resistive state is an excellent candidate for single-photon detection. However, the ubiquitous fluctuations in the junction strongly influence the stability of the states and, thus, the transition from one to the other. Here, we present an experimental study of switching statistics of critical and retrapping currents of a JJ based on niobium WL in its hysteretic regime. The mean lifetimes of the two metastable states, namely, the zero-voltage superconducting state and finite-voltage resistive state, are estimated from the distributions. Further, close to the hysteresis crossover temperature, observed telegraphic noise in the time domain due to random switching between the states provides their lifetimes directly. We present a thermal model introducing a double-well (bistable) feature with an intriguing quantity with respect to the devices’ temperature states. The effects of temperature fluctuations on the stability of the states are shown. We discuss our results toward further improvement of the efficiency of superconducting WL or nanowire single-photon detectors.

Preface

The 7th International Workshop on Numerical Modelling of High Temperature Superconductors (HTS 2020) was held online, hosted by Dr Kévin Berger (University of Lorraine, Nancy, France), on the 22nd and 23rd June 2021. In fact, the HTS 2020 workshop was expected to be held in Nancy in May 2020 but has been postponed due to COVID-19.The workshop received 95 abstracts submitted for presentation and was attended by 115 delegates from around the world. The conference programme covered the latest research and developments in modelling methods and tools to facilitate the accelerated development of superconducting science and technology – including modelling fundamentals, coupled and uncoupled multiphysics problems and applications – with an emphasis on high-temperature superconducting materials.Selected papers presented at HTS 2020 have been published separately in a Special Focus Issue of the journal Superconductor Science and Technology (SUST). This present volume in the Journal of Physics: Conference Series (JPCS) collects together the remainder of the (eight) contributed papers submitted to the HTS 2020 proceedings in JPCS.List of Editors, Scientific committees are available in the pdf

Preface

The 14th European Conference on Applied Superconductivity (EUCAS 2019) was held in Glasgow, UK from the 1st to the 5th September 2019. The conference was attended by over 1000 delegates from around the world, drawn from both academia and industry. The conference programme covered the latest research and industrial developments in all areas of applied superconductivity including superconducting electronics, large-scale applications and superconducting materials.Selected papers presented at EUCAS 2019 have been published separately in a Special Focus Issue of the journal Superconductor Science and Technology (SUST). This present volume in the Journal of Physics: Conference Series (JPCS) collects together the remainder of the contributed papers submitted to the EUCAS 2019 proceedings.Editors:Edward Romans (Editor-in-chief)Mark AinslieKévin BergerNikolay BykovskiyOscar KennedyAnna PalauColin PegrumLoïc QuévalGuilherme Gonçalves SoteloWescley Tiago Batista de SousaMin Zhang

2D SQIF arrays using 20 000 YBCO high Rn Josephson junctions, a viewpoint

This is a viewpoint on the letter by E E Mitchell et al (2016 Supercond. Sci. Technol. 29 06LT01).

9th International Workshop on Processing and Applications of Superconducting (RE)BCO Large Grain Materials (PASREG2015)

The 9th International Workshop on Processing and Applications of Superconducting (RE)BCO Large Grain Materials (PASREG 2015) was held at the University of Liege, Belgium on September 02- 04, 2015, as a satellite conference of the European Conference on Applied Superconductivity (EUCAS 2015). The Chairman was Philippe Vanderbemden; Benoît Vanderheyden, David Cardwell, and Herbert C. Freyhardt served as Co-Chairmen. PASREG 2015 was the ninth in a series of international workshops previously held in Cambridge, UK (1997), Morioka, Japan (1999), Seattle, USA (2001), Jena, Germany (2003), Tokyo, Japan (2005), Cambridge, UK (2007), Washington D.C., USA (2010), and Tainan, Taiwan (2012).PASREG 2015 covered novel and important processing aspects of bulk High Temperature Superconductors (HTS) as well as bulk MgB2. Besides processing, the workshop highlighted advanced material characterization technologies and activation techniques, which revealed the superior superconducting properties of bulk HTS and MgB2. Novel developments and innovative applications involving bulk superconductors complemented the discussion and exchange of information. The workshop was attended by 63 participants from 19 different countries. A total of 50 contributions were presented, of which 31 were presented in oral form and 19 were presented as posters.Together with a ‘Special Issue’ of Superconductor Science and Technology, these proceedings gather a selection of original research papers presented at the workshop (including both oral and poster presentations). We greatly acknowledge all the effort of the authors.Philippe VanderbemdenBenoît VanderheydenHerbert FreyhardtDavid Cardwell

Feasibility of HTS Magnet Option for Fusion Reactors

National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan 1)Department of Quantum Science and Energy Engineering, Tohoku University, 6-6-01-2 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579, Japan 2)The Graduate University for Advanced Studies, 322-6 Oroshi-cho, Toki, Gifu 509-5292, Japan 3)Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8568, Japan 4)Research Institute of Superconductor Science and Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan

The London penetration depth inBaFe2As2 superconductors at high electron doping level**This article was originally submitted for the special section ‘Focus on the electromagneticproperties of iron-based superconductors’, Superconductor Science and Technology, volume23, issue 5.

We compare the temperature dependences of the in-plane London penetration depth (Δλab(T)) forseveral Ba(Fe1 − xTMx)2As2 (TM = Co, Ni,Pd, Co + Cu) superconductors at high concentration of electrons,ne, added per Fe site. We show that regardless of the transition metal TM, forne ≥ 0.12, the penetration depth has a power-law temperature dependence , but with the exponent n≈1.65, thus significantly lower than the valuen ≥ 2 previously reported for lower electron concentrations. On doping with electronsfrom the 3d shells, the magnitude of the variation with temperature ofΔλL(T) is larger for Ni substitution than for Co substitution, and larger forCo + Cu co-doping than for Ni co-doping. However, comparing the effect of 3d and 4d electrons, forthe isovalent elements Ni and Pd respectively, we found that the rates of change inpenetration depth with temperature are nearly identical for the two compounds.

A MgB2 12.5 kVA superconductor transformer

A 12.5 kVA, MgB2 superconductor transformer was designed as five alternating stacked coils between the primary andthe secondary windings. Hyper Tech Research Inc. (Hyper Tech) manufactured multifilamentMgB2 superconductor wire by using a patented process called thecontinuous tube filling and forming (CTFF) process. The CTFFMgB2 conductor was insulated with yttrium-stabilized zirconia (YSZ) using the chemical solutioncoating process. An all-copper former was designed and fabricated with an OD of 71 mm,ID of 42 mm and heights of 12 mm and 8 mm for primary and secondary coils, respectively.Two primary and three secondary coils were fabricated using the sol–gel insulatedMgB2 wire using the W&R coil technology. One of the primary coils was tested at 4.2 K whichshowed better than 250 A engineering critical current. These five coils were then stacked asin the design in alternating fashion and connected and instrumented for testing. Thetransformer was cooled in He gas first then in liquid helium. The tests showed that theindividual coils, the primary and the secondary windings performed better than the designcurrents. Also the open-circuit tests of the transformer showed that 1:1 transfer wasachieved.This article was originally submitted for the special issue ‘Selected papers fromthe International Conference on Superconductivity and Magnetism (ICSM2008) (Side,Turkey, 25–29 August 2008)’, Superconductor Science and Technology, volume 22, issue 3.

OVERVIEW OF ORGANIC SUPERCONDUCTORS

Organic materials which are usually used for insulators, were shown to be an electrical conductor by H. Akamatsu, H. Inokuchi, and Y. Matsunaga in 1954. Moreover, J.P. Ferraris et al. showed that TTF [center dot] TCNQ was stably metallic down to around 60 K in 1973. Because of a low dimensionality of organic compound, however, a stabilization of an electronic state and a destabilization of a periodic lattice constructed a charge density wave which led a metal-insulator transition (a Peierls transition). After overcoming this low dimensionality, D. Jerome et al. discovered the first organic superconductor, (TMTSF)[sub 2] PF[sub 6] ([Tc] = 0.9 K (12kbar)) in 1980. Then with the resisting up of [Tc] constantly, the superconductor [kappa]-(BEDT-TTF)[sub 2](NCS)[sub 2] ([Tc] = 10.4 K) was found in 1987 and the [Tc] of [kappa]-(BEDT-TTF)[sub 2]Cu[N(CN)[sub 2]]Cl, 12.8 K at 0.3kbar, is the highest among the TTF family. Moreover, when the authors included the C[sub 60] system is included as molecular superconductor, the [Tc] = 33 K of Cs[sub 2]RbC[sub 60] reaches the starting point of oxide superconductors. In this paper, the history of organic conductors is described in Sec. 2. In Sec. 3, the author chooses the typical example of organic superconductor,more » [kappa]-(BEDT-TTF)[sub 2]Cu(NCS)[sub 2], and the preparation, crystal structure, chemical and physical properties are reviewed. In Sec. 4, the mechanism of organic superconductors is discussed and the future of organic superconductors is finally presented. 118 refs.« less

X-RAY AND PHOTOELECTRON-SPECTRA-BASED ANALYSIS OF ELECTRONIC STRUCTURE OF HIGH-Tc SUPERCONDUCTORS

International Journal of Modern Physics BVol. 05, No. 08, pp. 1097-1146 (1991) ReviewsNo AccessX-RAY AND PHOTOELECTRON-SPECTRA-BASED ANALYSIS OF ELECTRONIC STRUCTURE OF HIGH-Tc SUPERCONDUCTORSE. Z. KURMAEV and L. D. FINKELSTEINE. Z. KURMAEVInstitute of Metal Physics, USSR Academy of Sciences, Urals Division, Sverdlovsk, GSP-170, USSR and L. D. FINKELSTEINInstitute of Metal Physics, USSR Academy of Sciences, Urals Division, Sverdlovsk, GSP-170, USSRhttps://doi.org/10.1142/S0217979291000559Cited by:4 Next AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail You currently do not have access to the full text article. Recommend the journal to your library today! FiguresReferencesRelatedDetailsCited By 4Effect of extra oxygen intercalation on the modulation structure and electronic structure of the Bi2201 systemG Xu, Z Mao, H Yan, X Liu and C Xu et al.1 January 1999 | Superconductor Science and Technology, Vol. 11, No. 5Electronic spectrum of Bi2Sr2CaCu2O8 near the fermi level from results of numerical calculations and ultraviolet (8.43 eV) photoelectron spectroscopyA. M. Aprelev and A. A. Lisachenko1 Feb 1998 | Technical Physics Letters, Vol. 24, No. 2References1 Jan 1995Relation of the incommensurate modulation structure and normal-state properties of the Ba-doped Bi2Sr2CuO6+δ system Mao Zhiqiang, Tian Mingliang, Ji Mingrong, Zhu Jingsheng and Zuo Jian et al.1 April 1994 | Physical Review B, Vol. 49, No. 14 Recommended Vol. 05, No. 08 Metrics History Received 22 June 1990 PDF download

HIGH Tc SUPERCONDUCTIVITY OF Sr-La-Cu-O and Ba-Y-Cu-O THIN FILMS

International Journal of Modern Physics BVol. 01, No. 02, pp. 561-564 (1987) DEVICESNo AccessHIGH Tc SUPERCONDUCTIVITY OF Sr-La-Cu-O and Ba-Y-Cu-O THIN FILMSB.R. Zhao, L. Li, Y. Lu, H.S. Wang, Y.H. Shi, Y.Y. Zhao, C.W. Yuan, and J. GaoB.R. ZhaoThe Institute Of Physics, Academia Sinica, Beijing, China, L. LiThe Institute Of Physics, Academia Sinica, Beijing, China, Y. LuThe Institute Of Physics, Academia Sinica, Beijing, China, H.S. WangThe Institute Of Physics, Academia Sinica, Beijing, China, Y.H. ShiThe Institute Of Physics, Academia Sinica, Beijing, China, Y.Y. ZhaoThe Institute Of Physics, Academia Sinica, Beijing, China, C.W. YuanThe Institute Of Physics, Academia Sinica, Beijing, China, and J. GaoThe Institute Of Physics, Academia Sinica, Beijing, Chinahttps://doi.org/10.1142/S0217979287000876Cited by:7 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail You currently do not have access to the full text article. Recommend the journal to your library today! FiguresReferencesRelatedDetailsCited By 7Basic Properties and Parameters of SuperconductorsReinhold Kleiner15 July 2016Introduction26 September 2015FundamentalsReinhold Kleiner, Roland Hott, Thomas Wolf, Gertrud Zwicknagl and Mikhail Belogolovskii et al.30 January 2015Einleitung22 March 2013The AC Josephson and DC superconducting quantum interference device (SQUID) effects in YBCO large bridge devices at 77 KC X Fan and G G Siu1 January 1999 | Superconductor Science and Technology, Vol. 5, No. 1The Vibrational Spectra and Normal Coordinate Analysis of Semiconducting Y 2 BaCuO 5Y. M. Guo and R. A. Condrate23 September 2006 | Spectroscopy Letters, Vol. 24, No. 9Study of High Quality YBa2Cu3O7-y Thin FilmsB. R. Zhao, C. W. Yuan, J. Gao, Y. Z. Zhang and P. Out et al.1 Jan 1989 Recommended Vol. 01, No. 02 Metrics History PDF download