Indirect exchange interaction in thin ferromagnet—nonmagnetic structures: the influence of size quantization

• Published in: Journal of magnetism and magnetic materials 1995, Vol.139 (1), p.179-188
• Main Authors: Genkin, G.M., Sapozhnikov, M.V.
• Format: Article
• Language: English
• ISSN: 0304-8853
• DOI: 10.1016/0304-8853(95)90045-4

The properties of the indirect exchange interaction between the ferromagnetic layers placed in a nonmagnetic metallic film are calculated. The influence of dimensional quantization is investigated. We consider models with a parabolic energy spectrum of electrons and both infinite and finite potential barriers on the film boundaries. The electron spin density distribution in the film, aroused by the δ-layer of magnetic moments, is calculated. The indirect interaction between two such magnetic δ-layers versus their position in the film of nonmagnetic metals is investigated. It is shown that (contrary to thicker films) in sufficiently thin films the change of sign of the exchange interaction takes place only once: being ferromagnetic for distances less than ≈ k −1 f and antiferromagnetic for larger distances. As it turns out, the height of the barriers does not qualitatively affects the results, if E f lies below the edge of the barriers. Besides, the obtained value of the antiferromagnetic indirect exchange interaction is significantly higher in the case of thin films, than the ordinary RKKY interaction in the bulk metal. The properties of the indirect interaction between two magnetic δ-layers, situated in the semi-infinite space of a nonmagnetic metal, and the influence of the boundary with the vacuum are investigated, too.