Longitudinal critical current in type II superconductors. II. Helical vortex instability near the surface
The calculation of the critical current for helical instability of the flux-line lattice, performed in a previous paper for a bulk superconductor, is extended to include the effect of a planar surface. The extension is of interest since an applied longitudinal current in general flows near the surface before the helical instability of flux-line lattice triggers the transition to the flux-flow state. The magnetic stray field of the surface increases the critical current by a factor 1.41 (1.34) for weak (moderate) pinning, and it modifies the axis ratio of the helices. The pitch length and the extension of the helical mode into the specimen are decreased from their bulk values by surface pinning, but they are slightly increased if bulk pinning dominates.
- Research Organization:
- Max-Planck-Instut fuer Metallforschung, Institut fuer Physik, Stuttgart, Germany
- OSTI ID:
- 6264444
- Journal Information:
- J. Low Temp. Phys.; (United States), Journal Name: J. Low Temp. Phys.; (United States) Vol. 44:1; ISSN JLTPA
- Country of Publication:
- United States
- Language:
- English
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