Contribution of quantum corrections and superconducting fluctuations to the magnetic field and temperature dependence of the conductivity in amorphous CuTi and CuZr alloys

Abstract

We report conductivity measurements on Cu x Ti100−x and Cu x Zr100−x glasses as a function of magnetic field (0≦B≦6T) and temperature (1.5<T<60K). Samples were prepared by rapid quenching from the melt and in some cases by dc magnetron sputtering. The magnetoconductivity Δσ was determined below 20K with a relative error of 10−5. At low temperatures the measured conductivityσ(T,B)=σ 0+δσ(T)+Δσ(B,T) is compared quantitatively with the predictions of diagrammatic perturbation theories including quantum interference effects, spin-orbit scattering and electron-electron interaction. We obtain a set of characteristic fields for inelastic and spin orbit scattering from both the magnetic field and the temperature dependence of the measured σ(T, B). Below about 4K the Coulomb interaction determines δσ(T) in consistence with the Hall effect, whereas quantum interference processes and spin-orbit scattering dominate the magnetic field dependence. In case of Cu x Zr100−x , Δσ(B, T) can be explained by taking into account superconducting fluctuations (Maki-Thompson and Aslamasov-Larkin parts) in addition. Superconducting fluctuations dominate the temperature dependence as well. For high magnetic fields and lower temperatures (B/T>1T/K) we find discrepancies between experiment and calculations from perturbation theory.