Calculation of the temperature dependence of the thermal emf in amorphous alloys CaxAl1?x and AuxNi1?x

Abstract

The temperature dependence of the thermal emf of CaxAl1−x and AuxNi1−x for four different concentrations of the components of the alloys is calculated on the basis of the concept of dynamic concentrated excitations in amorphous metal systems. It is shown that increasing x from 0.15 to 0.50 in AuxNi1−x raises the thermal emf, and a further increase in the Au concentration from 0.50 to 0.80 lowers S(T). For CaxAl1−x the dependence S(T) is calculated in the interval of Ca concentrations from 0.55 to 0.75. In this concentration interval the thermal emf decreases as x is increased. It is shown that for both types of alloys the S(T) curve bends abruptly at a temperature near ≈10T0 (where T0 is the concentration-dependent characteristic temperature of amorphous alloys separating the ranges of strong and weak scattering of electrons by dynamic concentration excitations). The so-called S(T) “knee” shifts toward lower temperatures when the thermal emf increases with increasing x and toward higher temperatures when S(T) decreases with increasing x. The results agree with experimental data.