Magnetic properties of impurities and impurity pairs in magnetic multilayers

Spin-dependent scattering is considered to be the origin of giant magnetoresistance in magnetic multilayers, although the role of bulk or interface defects is still under discussion. We present calculations of spin-dependent impurity scattering potentials as a function of the impurity position in a Co/Cu-multilayer. The calculations are performed within spin density functional theory using a Green function method (the tight binding Korringa-Kohn-Rostoker method). It is shown that the impurity potential depends strongly on the impurity position, which is reflected in local densities of states and local impurity moments. Furthermore, calculations of magnetic properties of impurity pairs at the interface are presented and compared with results for single impurities.