Flux Flow of Pure and Dirty Superconductors

Abstract

Transport properties in the flux-flow regime such as flux-flow resistance, the Hall effect, and the Ettingshausen effect are very interesting because they give valuable information on the dynamic behavior of the superconducting order parameter. Pure Nb and V metals and NbMo and NbTa alloys were used as pure and dirty samples, respectively. Results on pure Nb, the NbMo alloy system, and the Nb₈₀Ta₂₀ alloy were reported earlier.^1,2 Emphasis in these reports was placed on the quantitative comparison of various experimental transport phenomena in higher fields near H _c2 with microscopic theories based on the time-dependent Ginzburg—Landau equation. As described in Ref. 2, while the results of the Ettingshausen effect experiments can be well accounted for in accordance with Maki’s microscopic theory, observations of the flux-flow resistance, the Hall angle, and the thermal conductivity are in quantitative disagreement with theory. In this paper we describe our study of the flux-flow resistance of pure V and the NbTa alloy system. While the experimental behavior of the flux-flow resistance has not yet been established, theoretical work has shown considerable progress since the report in Ref. 2.