ELECTRICAL RESISTIVITY OF DISORDERED CRYSTALLINE ALLOYS

Abstract

The Ziman-type theory of the electrical resistivity of liquid metals is extended to disordered crystalline alloys by means of a prescription given by Baym. The formulae for calculating the resistivity of these systems are presented and the temperature dependence of the resistivity in both low and high temperature range is discussed in some detail. By using the Debye model for lattice vibration, we can express the resisti-vity of a disordered system as ρ=ρ0+ρd(T/Θ)2+ρi(T/Θ)5 at temperatures well below Debye temperature,Θ , this behavior is compatible with experiments. On account of the Debye-Waller factor and multi-phonon effects, the resistivity approaches saturation at high temperature instead of the exhibiting a linear T-dependence predicted by onephonon approximation. A comparison between experimental data and a simple expression derived on the basis of the approximation of independent vibration of atom shows that the deviation from linearity of the high temperature resistivity similar to that of Nb can be understood with the present model.