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MA: Magnetismus

MA 26: Mikro- und nanostrukturierte Materialien

MA 26.12: Vortrag

Donnerstag, 11. März 2004, 18:00–18:15, H10

Domain wall orientation in magnetic nanowires: Anisotropy of the exchange interaction — •André Kubetzka, Elena Vedmedenko, Kirsten von Bergmann, Oswald Pietzsch, Matthias Bode, and Roland Wiesendanger — Institute of Applied Physics, University of Hamburg, Jungiusstrasse 11, D-20355 Hamburg, Germany

Scanning tunneling microscopy reveals that domain walls in two atomic layers thick Fe nanowires on W(110) are oriented along the [110] crystallographic direction, regardless of the orientation of the wires. Micromagnetic continuum theory with an isotropic exchange stiffness, however, predicts the walls to be oriented perpendicular to the wire axis. We demonstrate by MC simulations on a discrete lattice that the wall orientation is determined by the atomic lattice structure and the strength of an anisotropic Heisenberg-like exchange interaction. The magnetic anisotropy and the magnetostatic energy which can govern wall directions in bulk material do not play any role in the ultrathin film limit.