Visualizing the mechanism that determines the critical current density in polycrystalline superconductors using time-dependent Ginzburg-Landau theory

Abstract

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

Probes for investigating the effect of magnetic field, field orientation, temperature and strain on the critical current density of anisotropic high-temperature superconducting tapes in a split-pair 15 T horizontal magnet

“…1,22 Access to variable-temperature and variable-strain measurements (in one probe) on a single sample enabled a resolution of the apparent contradiction between strain scaling (found at fixed temperature) 18 and temperature scaling (at fixed strain). [23][24][25][26] This led to a general scaling law 23,24,27 for LTS materials which includes a 1/κ 2 term 28 (κ: GinzburgLandau constant) that gives best fits to the data for Nb 3 Sn 23,29 and Nb 3 Al 30 and is consistent with computational data 31 and general analytic forms. 32,33 An excellent bending beam apparatus was also developed at the University of Twente for short samples of LTS wires.…”

The cause of ‘weak-link’ grain boundary behaviour in polycrystalline Bi2Sr2CaCu2O8and Bi2Sr2Ca2Cu3O10superconductors

“…In polycrystalline low temperature superconductors (LTS), such large forces were often achieved by reducing the grain size. This increased the force necessary to drive fluxons along the grain boundaries, from one side of the sample to the other, by increasing the density of grain boundary triple points and the distortions of the fluxons required for them to move [2,3]. In high temperature superconductors (HTS), the pinning force has often been increased by adding inclusions that pin each fluxon [4].…”

The critical current density of an SNS Josephson-junction in high magnetic fields

“…Although high-field solutions for SNS J-Js are available 16,18 (36) and (37) in (9) and (10) to solve for c 1 …”

“…We have long known that although characterizing grain boundary pinning using just the size of the grains is useful for describing similar superconducting materials with different grain sizes 35 , it is very simplistic. Visualisation of solutions to the TDGL equations 14 for polycrystalline materials has shown that fluxons cross the superconductor by flowing along the grain boundaries 36 37,38 .…”