Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 33: Poster II

MA 33.18: Poster

Freitag, 26. März 2010, 11:00–14:00, Poster B1

Mangnetic domain patterns in Co2MnGe Heusler thin film microstructures — Katherine Gross, •Philipp Szary, Melanie Ewerlin, Frank Brüssing, Alexandra Schumann, Oleg Petracic, Kurt Westerholt, and Hartmut Zabel — Institut für Experimentalphysik IV, Ruhr-Universität Bochum, 44780 Bochum, Germany

Cubic Heusler alloys like Co2MnGe are soft feromagnetic materials with a weak cubic crystalline magnetic anisotropy. Thin films of Co2MnGe can be grown on sapphire a-plane with a dominating growth-induced uniaxial magnetic anisotropy, which originate from the miscut of the single crystalline substrate. This feature makes this Heusler alloy ideally suited for the study of magnetic domain structures resulting from the competition between an uniaxial growth-induced magnetic anisotropy and the shape anisotropy in magnetic microstructures. Using electron beam lithography we have prepared rectangular stripes of Co2MnGe with the length to width aspect ratios m = l/b from m=1 to m=20. The magnetic domains are observed by magnetic force microscopy in the remanent state as well as with an applied magnetic field up to 600 Oe. We find regular, highly symmetric domain patterns in the stripes, changing systematically with the aspect ratio and the applied magnetic field. When the uniaxial anisotropy is oriented perpendicular to the shape anisotropy, the domain width along the long axis of the stripes scales as 1/m. The essential features of the domain patterns we have observed could well be reproduced by OOMMF micromagnetic simulations.