First-principles exchange interactions between ferromagnetic and antiferromagnetic films: Co on NiMn, a case study

Heisenberg exchange parameters at the interface of antiferromagnetic NiMn with ferromagnetic Co are calculated from first principles. We use a layer version of the Korringa-Kohn-Rostocker multiple-scattering approach and an expression, which is based on the expansion of the band energy, to calculate the exchange parameters from the underlying electronic structure. For bulk systems, the parameter sets yield Curie temperatures that are in good agreement with experimental values. In the interface region, the interlayer interactions in NiMn change significantly compared to the bulk while the intralayer interactions are almost unchanged. (C) 1998 American Institute of Physics. [S0021-8979(98)48511-6].