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Transport Jc in Bulk Superconductors: A Practical Approach?


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Authors

Rush, JP 
May-Miller, CJ 
Palmer, KGB 
Rutter, NA 
Dennis, AR 

Abstract

The characterisation of the critical current density of bulk high temperature superconductors is typically performed using magnetometry, which involves numerous assumptions including, significantly, that Jc within the sample is uniform. Unfortunately, magnetometry is particularly challenging to apply where a local measurement of Jc across a feature, such as a grain boundary, is desired. Although transport measurements appear to be an attractive alternative to magnetization, it is extremely challenging to reduce the cross-sectional area of a bulk sample sufficiently to achieve a sufficiently low critical current that can be generated by a practical current source. In the work described here, we present a technique that enables transport measurements to be performed on sections of bulk superconductors. Metallographic techniques and resin reinforcement were used to create an I-shaped sample of bulk superconductor from a section of Gd-Ba-Cu-O containing 15 wt % Ag2O. The resulting superconducting track had a cross-sectional area of 0.44 mm2. The sample was found to support a critical current of 110 A using a field criterion in the narrowed track region of 1 μV cm-1. We conclude, therefore, that it is possible to measure critical current densities in excess of 2.5 x 108 A m-2 in sections of a bulk superconductor.

Description

Keywords

Critical current density, current transport measurements, high temperature superconductors, rare-earth barium copper oxide

Journal Title

IEEE Transactions on Applied Superconductivity

Conference Name

Journal ISSN

1051-8223
1558-2515

Volume Title

Publisher

Institute of Electrical and Electronics Engineers (IEEE)
Sponsorship
Engineering and Physical Sciences Research Council (EP/P00962X/1)
Engineering and Physical Sciences Research Council (EP/K02910X/1)
Engineering and Physical Sciences Research Council (EP/L504920/1)
This work was supported by the Engineering and Physical Sciences Research Council, via a Doctoral Training Award (grant number is EP/L504920/1) and funding from grant number EP/K02910X/1. This work was also supported by the Boeing Company. All data are provided in full in the results section of this paper.