Spontaneous resistivity anisotropy in nickel-copper alloys

The longitudinal and transverse magnetoresistivity of pure nickel and its alloys containing 9.38, 18.77 and 28.32 at.% of copper were measured from room temperature to temperatures well above their Curie temperature in fields up to 10 kOe. A theory based on the well known two-current conduction model proved adequate to explain the temperature dependence observed for the spontaneous resistivity anisotropy Delta rho s / rho =( Delta rho /sub //s/(T)- Delta rho perpendicular to s (T))/ rho . Based on this theory, the temperature dependence of spin-up ( rho spin up i (T)) and spin-down ( rho spin down i (T)) resistivities was computed. The temperature dependence of resistivity for the two spin directions demonstrated that (i) both s-s and s-d scattering processes contribute to tau spin down i (T) as contrasted with rho spin up i (T) which arises solely from s-d scattering and (ii) contribution to rho spin down i (T) from s spin down-d spin down scattering dominates s spin down-s spin down scattering for temperatures in the immediate vicinity of room temperature, whereas the reverse situation arises for temperatures close to the Curie temperature.