Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 20: Magnetic Thin Films II
MA 20.8: Vortrag
Mittwoch, 28. März 2007, 17:00–17:15, H5
Magnetic orbital moment and uniaxial anisotropy in tetragonally distorted Fe1−xCox films — Fikret Yildiz, •Marek Przybylski, Feng Luo, Carsten Tieg, Radu Abrudan, and Jurgen Kirschner — Max-Planck-Institut fur Mikrostrukturphysik, Halle, Germany
The quenching of the orbital moment, which occurs in high lattice symmetries, can be removed by a symmetry reduction. The unquenched orbital magnetization is accompanied by a significant anisotropy of the orbital moment itself, which in turn induces a strong magnetic anisotropy owing to spin-orbit coupling. Previously we have shown that the Fe1−xCox alloy films of the composition around x=0.5−0.6 show a clear out-of-plane easy axis of magnetization when their fcc lattice is tetragonally distorted. Rectangular polar magneto-optical Kerr loops were measured up to a thickness dc, which was found to depend strongly on the film composition. Here we report on the magnetic circular dichroism in soft x-ray absorption measurements of the same Fe1−xCox tetragonally distorted films, which were carried out at the UE56/2-PGM2 beamline at BESSY in Berlin. In contrast to fcc-crystals of cubic symmetry where the orbital moment is almost completely quenched, a strong enhancement of the Co orbital moment is found - depending on composition - with a maximum value at x=0.6. This dependence of the orbital moment coincides well with the composition dependence of the dc, which is a measure of the volume magnetocrystalline anisotropy.