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MA: Fachverband Magnetismus

MA 52: Magnetic Thin Films III

MA 52.6: Vortrag

Donnerstag, 17. März 2011, 12:15–12:30, HSZ 403

Magnetic domain patterns in Co2MnGe-Heusler nanostripes — •Katherine Gross, Philipp Szary, Oleg Petracic, Kurt Westerholt, and Harmut Zabel — Festkörperphysik, Ruhr Universität Bochum, D-44780 Bochum, Germany

We have investigated the magnetic domain patterns of Co2MnGe-Heusler microstructures resulting from the interplay between the magneto-crystalline, growth induced uniaxial, and shape anisotropies. Before patterning, thin films of ferromagnetic Co2MnGe Heusler alloys grown on Al2O3 a-plane substrates exhibit, besides a small cubic anisotropy, a dominant in-plane uniaxial anisotropy parallel to the Al2O3 -c-axis. On submicron wide slabs prepared by electron beam lithography we analyzed the influence of the slab geometry (width,length and thickness) on the magnetic domain configurations by magnetic force microscopy (MFM) and SQUID Magnetometry. In the remanent state with the uniaxial anisotropy axis perpendicular to the long axis of the slabs we observed perfectly regular multidomain patterns with the magnetization direction perpendicular to the slab axis and the domain width varying approximately as the square root of the slab width. For an oblique orientation between the slab axis and the uniaxial anisotropy axis (0°<α<90°) the magnetization switches from a multidomain configuration to a single domain dipole state below a critical angle αC, which depends on the width of the stripes. The essential features of the domain patterns that we have imaged by MFM could well be reproduced by OOMMF micromagnetic simulations.