# Critical fields and flux-flow resistances in strongly disordered ultra-thin superconducting films

Gupta, Das K and Soman, Swati S and Chandrasekhar, N (2003) Critical fields and flux-flow resistances in strongly disordered ultra-thin superconducting films. In: 23rd International Conference on Low Temperature Physics (LT23), 20-27 August 2002, Hiroshima, Japan, pp. 771-772.

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## Abstract

Strongly disordered ultra-thin films of Bi and $Sn(<100\AA)$ produced by quench-condensation, are well known systems that show insulator to superconductor transition. Some aspects of the transition and the nature of the superconducting state are weakly dependent on the material and substrate, but we find that the critical field $(B_c_2)$ of Bi and Sn films of comparable resistance show different temperature dependences. For Sn the mean field $B_c_2$ is seen to vary with temperature as $B_c_2(T)=B_c_2(0)(1-(T/T_c))^2$ whereas for Bi it is found to be $B_c_2(T)=B_c_2(0)(1-(T/T_c))^\alpha$ with $\alpha \approx 1.14.$ In films with low sheet resistance we find a dissipationless vortex-solid regime. The flux-flow resistance calculated from the I–V traces taken in several magnetic fields show a much faster field dependence than existing theories predict.

Item Type: Conference Paper Elsevier Copyright of this article belongs to Elsevier. Flux-flow;Critical field;Vortex-solid;Disorder;Quench-condensed Division of Physical & Mathematical Sciences > Physics 13 Aug 2007 19 Sep 2010 04:37 http://eprints.iisc.ac.in/id/eprint/10658