Dresden 2003 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 11: Postersitzung II (Metall-Isolator-Überg
änge, Phasenüberg
änge in Quantensystemen, Theorie: Systeme korrelierter Elektronen)

TT 11.23: Poster

Dienstag, 25. März 2003, 14:30–19:00, P2c, P2d

Magnetism and electronic structure of Kondo-lattice films with finite band occupation — •Jochen Kienert and Wolfgang Nolting — Institut fuer Physik, Humboldt-Universitaet zu Berlin, Invalidenstrasse 110, 10115 Berlin

The magnetic and electronic properties of thin ferromagnetic films based on the Kondo-lattice model are investigated. We emphasize the role of finite conduction band occupation. In addition to the exchange mechanism in ferromagnetic semiconductors like EuO or EuS, which have been studied quite extensively in the past, the presence of mobile charge carriers leads to an RKKY-like coupling of the localized magnetic moments (as is realized, e. g., in Gd). Our approach takes account of electron correlation effects on this coupling. Several quantities of interest, like the charge excitation spectrum, the critical temperature, and interlayer exchange coupling are determined within a self-consistent scheme. We observe strong dependencies on temperature, film thickness, and band occupation. The interlayer exchange coupling between ferromagnetic layers separated by non-magnetic spacer layers exhibits oscillatory behavior. An outlook on the combination of local-moment and Hubbard films is given.