ELECTRONIC STATES AND MAGNETORESISTANCE IN MULTILAYERS

The microscopic origin of the giant magnetoresistance in metallic multilayers is ascribed to a spin dependent random exchange potential caused by roughness of the interfaces. The random exchange potential is self-consistently determined by calculating the density of states near the interfaces and the material dependence of the magnetoresistance is systematically studied for Fe/NM, Co/NM and FM/Cu multilayers where NM and FM denote nonmagnetic and ferromagnetic transition metal elements, respectively. The theoretical results are compared with the experimental ones. An expression of the thermoelectric power is derived and its relation to the magnetoresistance is clarified. Dependence of the thermal conductivity on the magnetic field is also discussed.