FIRST PRINCIPLES CALCULATIONS OF INTERLAYER EXCHANGE COUPLING IN BCC FE CU/FE STRUCTURES/

We report on theoretical calculations of interlayer exchange coupling between two Fe layers separated by a modified Cu spacer. These calcula tions were motivated by experimental investigations of similar structu res by the SFU group. The multilayer structures of interest have the g eneral form: Fe/Cu(k)/Fe and Fe/Cu(m)/X(1)/Cu(n)/Fe where X indicates one AL (atomic layer) of foreign atoms X (Cr, Ag or Fe) and k, m, n re present the number of atomic layers of Cu. The purpose of the experime ntal and theoretical work was to determine the effect of modifying the pure Cu spacer by replacing the central Cu atomic layer with the atom ic layer of foreign atoms X. The first principles calculation were per formed using the Layer Korringa-Kohn-Rostoker (LKKR) method. The theor etical thickness dependence of the exchange coupling between two semi- infinite Fe layers was calculated for pure Cu Spacer thicknesses in th e range of 0<k<16. The effect of the foreign atoms X on the exchange c oupling was investigated using the structure with 9 AL Cu spacer as a reference sample. The calculated changes in the exchange coupling are in qualitative agreement with experiment.