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

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, Tsub(c) and -(dHsub(c2)/dT)sub(Tc), and electrical properties, rhosub(n) and (1/rhoRT)(drho/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 Tsub(c), -(dHsub(c2)/dT)sub(Tc), rhosub(n) and (1/rhoRT)(drho/dT). The strong correlation between Tsub(c), rhosub(n) and (1/rhoRT)(drho/dT) was suggested to arise from the increase in N*(Esub(F)) and D which led to a decrease in rhosub(n) and increases in Tsub(c) and (1/rhoRT)(drho/dT) with decreasing silicon or germanium content. (author)