APPLICABILITY OF THE 2-CURRENT MODEL FOR SYSTEMS WITH STRONGLY SPIN-DEPENDENT DISORDER

The resistivities of the ferromagnetic alloy systems Fe-Ni and Co-Ni w ere studied in detail by application of first-principles techniques. F or that purpose the Kubo-Greenwood formalism was applied on the basis of electronic structure data obtained using the spin-polarized Korring a-Kohn-Rostoker coherent potential approximation method of band-struct ure calculation for randomly disordered ferromagnetic alloys. One set of calculations was carried out fully relativistically, while for a se cond one the well-known and often applied two-current model was used. We compare the results of the two approaches as well as the difference between the calculated two-current resistivities and the resistivitie s obtained experimentally by the usual decomposition based on the two- current model. We discuss the validity of the two-current model for th e systems investigated and the reason for the apparent success of this model. [S0163-1829(97)09140-6].