Possible Approach to the Low-Temperature Resistance Maximum in Dilute Alloys of Transition Metals in Noble Metals

Abstract

If a dilute alloy of a transition metal in a noble metal becomes ferromagnetic, the spin degeneracy of the ground state of the impurity atom is removed by the local field. Scattering of the conduction electrons by the impurity atoms can then take place by inelastic as well as elastic collisions. Assuming the scattering cross section for elastic scattering is larger for the lower lying nondegenerate states, one gets the following results: (1) There is a maximum in the temperature dependent resistivity. (2) The temperature at which the maximum occurs varies rapidly with concentration of the transition metal. (3) The magnetoresistance is negative up to some temperature higher than the temperature at which the maximum in resistivity occurs. The experimental observations of Gerritsen and Linde and of Gerritsen on the resistivity of these alloys are, for the most part, in qualitative agreement with these consequences. This model does not require the existence of localized electronic states with energy near the Fermi energy as does the model presented by Korringa and Gerritsen.