Vortex dynamics and upper critical fields in ultrathin Bi films

Sambandamurthy, G and Chandrasekhar, N and Gupta, Das K (2001) Vortex dynamics and upper critical fields in ultrathin Bi films. In: Physical Review B, 63 (21). p. 214519.

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Abstract

Current-voltage (I-V) characteristics of quench condensed, superconducting, ultrathin Bi films in a magnetic field are reported. These I-V's show hysteresis for all films, grown both with and without thin Ge underlayers. Films on Ge underlayers, close to superconductor-insulator transition, show a peak in the critical current, indicating a structural transformation of the vortex solid. These underlayers, used to make the films more homogeneous, are found to be more effective in pinning the vortices. The upper critical fields (B-c2) of these films are determined from the resistive transitions in perpendicular magnetic field. The temperature dependence of the upper critical field is found to differ significantly from Ginzburg-Landau theory, after modifications for disorder.

Item Type:	Journal Article
Publication:	Physical Review B
Publisher:	The American Physical Society
Additional Information:	Copyright of this article belongs to The American Physical Society.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	09 Nov 2011 05:58
Last Modified:	09 Nov 2011 05:58
URI:	http://eprints.iisc.ac.in/id/eprint/40385

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