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The critical current density of grain boundary channels in polycrystalline HTS and LTS superconductors in magnetic fields

Sunwong, P.; Higgins, J.S.; Tsui, Y.; Raine, M.J.; Hampshire, D.P.

The critical current density of grain boundary channels in polycrystalline HTS and LTS superconductors in magnetic fields Thumbnail


Authors

P. Sunwong

J.S. Higgins

Y. Tsui



Abstract

We provide evidence that a single mechanism—flux flow along channels—can explain the functional form of the critical current density (Jc) in the low-temperature superconductor Nb3Sn and in the high-temperature superconductors (HTS) YBa2Cu3O7−δ (YBCO) and (Bi,Pb)2Sr2Can−1CunOx (BiSCCO) in low and high magnetic fields. In this paper, we show that standard flux pinning theories, used for the past four decades to describe Jc in low-temperature superconductors (LTS), cannot explain the strain dependence of Jc in YBCO because Jc is a function of strain but the average superconducting properties are not. We conclude that in the polycrystalline samples presented here, the channels are grain boundaries that are narrow and metallic in Nb3Sn and YBCO but wide and semiconducting in BiSCCO. In Nb3Sn, strain alters Jc by changing the superconducting properties of the grains, whereas in YBCO, strain alters Jc by changing the properties of the grain boundaries.

Journal Article Type Article
Publication Date Sep 1, 2013
Deposit Date Sep 17, 2013
Publicly Available Date Dec 16, 2014
Journal Superconductor Science and Technology
Print ISSN 0953-2048
Electronic ISSN 1361-6668
Publisher IOP Publishing
Peer Reviewed Peer Reviewed
Volume 26
Issue 9
Article Number 095006
DOI https://doi.org/10.1088/0953-2048/26/9/095006
Public URL https://durham-repository.worktribe.com/output/1447196

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Copyright Statement
© 2013 IOP Publishing Ltd. This is an author-created, un-copyedited version of an article accepted for publication in Superconductor science and technology. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0953-2048/26/9/095006.






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