Regensburg 2007 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 26: Exchange Bias

MA 26.2: Vortrag

Donnerstag, 29. März 2007, 15:30–15:45, H10

Interlayer exchange interaction in local-moment systems: doping-induced switching of the coupling — •Jochen Kienert and Wolfgang Nolting — Festkörpertheorie, Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany

We present an RKKY study of the interlayer exchange coupling (IEC) between localized magnetic moments for layered structures of finite thickness. Whereas the main focus in the work on IEC has been put on the oscillatory spatial dependence using bulk-like spacers and considering large spacer thickness [1-3], we investigate the influence of reduced dimensionality, small separations of the magnetic layers, and charge carrier density. The interplay between the localized perturbing potential and confinement effects leads to a strong dependence of the interlayer interaction on the charge carrier density/doping. Most drastically, we observe a switching of the IEC tunable by interlayer hopping and band filling, and there is a complete magnetic interlayer decoupling for certain band occupations. The inclusion of correlations beyond perturbation theory in the Kondo lattice (or sd-, sf-, double exchange) model and their consequences for IEC are discussed.The dependence of the interlayer coupling on the charge carrier density is of current interest in diluted magnetic semiconductor heterostructures and in manganite bilayer systems.

[1] P. Bruno, J. Phys.: Condens. Matter 11, 9403 (1999)

[2] M.D. Stiles, in: Ultrathin Magnetic Structures III, Springer 2005

[3] Y. Yafet, Phys. Rev. B. 36, 3948 (1987)