An in depth characterization of (NbTa)&amp;lt;inf&amp;gt;3&amp;lt;/inf&amp;gt;Sn filamentary superconductor

Supercond. Sci. Technol.

2002

The engineering critical current density (J E ) and the index of transition, N (where E = αJ N ), of a Nb 3 Al multifilamentary strand, mass-produced as a part of the Fusion programme, have been characterized as a function of field (B), temperature (T ) and strain (ε) in the ranges B 15 T, 4.2 K T 16 K and −1.79% ε +0.67%. Complementary resistivity measurements were taken to determine the upper critical field (B C2 (T , ε)) and the critical temperature (T C (ε)) directly. The upper critical field defined at 5%ρ N , 50%ρ N or 95%ρ N , is described by the empirical relation B ρ N C2 (T , ε) = B ρ N C2 (0, ε) 1 − T T ρ N C (ε) ν . The upper critical field at zero 0953-2048/02/070991+20$30.00 © 2002 IOP Publishing Ltd Printed in the UK b 1 2where the Ginzburg-Landau (GL) parameter κ is given by the relation, γ is the Sommerfeld constant and t = T/T C (ε). At an applied field equal to the upper critical field found from fitting the Kramer dependence (i.e. at B C2 (T , ε)), the critical current is non-zero and we suggest that the current flow is percolative. The functional form of F P implies that in high fields the grain boundary pinning does not limit J E , this is consistent with J E -microstructure correlations in other superconducting materials.

Section: Discussionmentioning

confidence: 62%

“…Average values of p and q as a function of temperature for the Nb 3 Al strand from the fits to the data in the strain range −1.79% ε 0.67% where B C2 is constrained by resistivity measurement. (T , ε), an empirical relation for κ has been found of the form [35,69]…”

Section: A Single Scaling Lawmentioning

confidence: 99%

The strain and temperature scaling law for the critical current density of a jelly-roll Nb3Al strand in high magnetic fields

Keys

Koizumi

Supercond. Sci. Technol.

2002

“…The materials with the lowest c / DSc are polycrystalline materials, including MgB2 [81] and A15 materials [66,67,82,83]. Although removing high angle grain boundaries from technological polycrystalline materials is the favoured route to increase c , so far, this approach has proven very expensive.…”

Section: Resultsmentioning

confidence: 99%

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

Wang

Raine

Supercond. Sci. Technol.

2018

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“…13 The main contribution of Kramer's original theoretical work was to explain how the universal scaling of F P , which had been well established experimentally at that time, could arise. However, the details of the theory are not reliable since Kramer used an incorrect FLL shear modulus ͑C 66 ͒, which when corrected gives the wrong field dependence 14 for J C . For simplicity, he also considered a two-dimensional ͑2D͒ system and assumed that the fluxons that sheared past stationary ͑pinned͒ fluxons were in a perfectly ordered hexagonal FLL.…”

mentioning

confidence: 99%

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

Carty

2008

Phys. Rev. B

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.