Effect of the Overdeposition of Gold on the Fluctuation-Induced Conductivity of Superconducting Aluminum Films

Abstract

Fluctuation-induced conductivity (FIC) above the superconducting transition temperature was investigated for aluminum films with respect to the effect of gold overdeposition. Thicknesses of gold were 0, 1/2, l and 3/2 atomic layer. The measured FIC was well explained by the traditional superconducting fluctuation theory. The values of the pair-breaking parameter δ increased with the increase of gold thickness. An experimental relation between the pair-breaking parameter δ and the normal sheet resistance \(R_{\text{n}}^{\Box}\), \(\delta = a+bR_{\text{n}}^{\Box}\), holds for the samples with 1 atomic layer of gold as for the unoverdeposited samples. The constant term a for the overdeposited samples is, however, larger than that for the unoverdeposited samples. This is considered to be due to the spin-orbit scattering effect owing to the existence of gold.