Correlation between superconducting characteristics and normal electrical resistivity for Zr-Si and Zr-Ge alloys in metastable BCC and amorphous phases

Abstract

The superconducting properties and normal electrical resistivity were investigated for series of Zr-Si and Zr-Ge alloys in metastable BCC and amorphous phases, produced by the melt-spinning technique. The formation of each metastable phase was limited to the composition ranges: 8-11 at.% Si or 9-12 at.% Ge for the BCC phase and 12-24 at.% Si or 13-21 at.% Ge for the amorphous phase. Two significant features were observed. Firstly, both the superconducting properties, Tc and -(dHc2/dT)Tc, and electrical properties, rho n and (1/ rho RT)(d rho /dT) varied monotonically with silicon or germanium content without any drastic discontinuity at the BCC and amorphous phase boundaries. Secondly, a strong correlation existed between Tc, -(dHc2/dT)Tc, rho n and (1/ rho RT)(d rho /dT). The strong correlation between Tc, rho n and (1/ rho RT)(d rho /dT) was suggested to arise from the increase in N*(EF) and D which led to a decrease in rho n and increases in Tc and (1/ rho RT)(d rho /dT) with decreasing silicon or germanium content.