Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 18: Poster I : Bio Magn. (1-2); Mag.Imgaging (3-9); Magn. Semiconductors (10-16); Half Metals & Oxides (17-20); Coupl.Phenomena (21-27); Magn. Mat. (28-41); Micro & Nanostr. Magn. Materials (42-61); Micro Magn. (62-64); Surface Magnetism (65-70); Transport Phenomena (71-85)

MA 18.70: Poster

Dienstag, 26. Februar 2008, 15:15–18:30, Poster E

Investigation of higher-order exchange interactions in magnetic nanostructures — •Samir Lounis, Peter H. Dederichs, and Stefan Blügel — IFF, Forschungszentrum Jülich, D-52425 Jülich, Germany

A realistic description of the complex magnetic phases in nanosystems on the basis of model Hamiltonians requires the exchange interactions beyond the standard Heisenberg term [1]. These are difficult to calculate by common DFT based first-principles methods. To calculate the biquadratic interactions by the Korringa-Kohn-Rostoker Green function (KKR-GF) method, a formula based on the magnetic force theorem is derived. Moreover, the full-potential KKR-GF method for non-collinear magnetism [2,3,4] has been used to investigate the complex magnetic structures of small Mn and Cr clusters of different sizes and shapes on the Cu(111) surface. Here, the importance of these additional interactions will be illustrated and discussed.

[1] Ph. Kurz, G. Bihlmayer, K. Hirai, S. Blügel, Phys. Rev. Lett. 86, 1106 (2001).

[2] S. Lounis, Ph. Mavropoulos, P. H. Dederichs, S. Blügel, Phys. Rev. B 72, 224437 (2005).

[3] S. Lounis, Ph. Mavropoulos, R. Zeller, P. H. Dederichs and S. Blügel, Phys. Rev. B 75, 174436 (2007).

[4] S. Lounis, M. Reif, Ph. Mavropoulos, L. Glaser, P. H. Dederichs, M. Martins, S. Blügel and W. Wurth, cond-mat/0608048.