Fluctuation conductivity of tin films below the superconducting transition temperature

Abstract

Measurements have been carried out of the temperature dependence of the fluctuation-induced excess electrical conductivity of thin (thickness much less than the Ginzburg-Landau coherence length) superconducting films of tin below the transition temperature. Two types of specimen were investigated: (a) films deposited on a glass substrate held at 300 K and (b) films deposited on a glass substrate at 300 K and then covered by a protective layer of germanium. Special care was taken to ensure sample homogeneity. Analysis of the results shows that the fluctuation parameter, ec, is not affected by the germanium layer. Its value is, however, much larger than that predicted by the theory of Kajimura, Micoshiba, and Yamaji.