Fully relativistic spin-polarized description of magnetic interface coupling: Fe multilayers in Au(100)

The spin-polarized fully relativistic screened Korringa-Kohn-Rostoker method is applied to calculate magnetic interface coupling energies (MICE's) for Fe multilayers in Au(100), separated by up to 16 spacer layers of Au. With respect to the antiparallel as well as to a perpendicular relative orientation of the magnetization in the Fe slabs the MICE's as calculated (a) in terms of total energies, (b) within the force theorem approximation, and (c) within the frozen potential approximation are discussed using the concept of layer-resolved quantities. In particular the comparison between the total energy and the force theorem approach is presented in some detail because of possible implications for an ab initio description of transport properties in multilayer systems.