Calculation of Oscillatory Exchange in bcc-Fe/Cu Multilayers
S. Krompiewski
Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland

J. Pirnay, U. Krey and F. Süss
Institute of Physics III, University of Regensburg, Germany
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Within a tight-binding LMTO approach in the atomic sphere approximation we calculate the exchange interaction, J, between magnetic Fe slabs in a periodic multilayer arrangement m Fe/n Cu/ .... We concentrate on cases, where Cu adapts to the bcc structure of Fe. For the "open" (100)-interface our results suggest that a minimal number of m = 13 Fe monolayers per Fe slab is necessary to get antiferromagnetic coupling. For m = 16 we find antiferromagnetic coupling for 8 ≤ n ≤ 14, i.e. a long period of ca. 11 and a short period of 2 Cu monolayers. In contrast, for the (110)-interfaces, only a long period of 14 monolayers is found, i.e. the coupling is antiferromagnetic for 7 ≤ n ≤ 14 already for small values of m. We then model the roughness by mutual interchange of 50% of the Fe and Cu atoms, respectively, in the interface layers and find that, due to the interchange, the coupling constant J, as a function of the Cu-spacer thickness n, roughly shifts by half a mono-layer to the right. In the (100)-case, the short period gets washed out by the roughness.
DOI: 10.12693/APhysPolA.85.475
PACS numbers: 75.70.Ak