Dresden 2006 – wissenschaftliches Programm
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MA: Magnetismus
MA 29: Magnetic Thin Films IV
MA 29.11: Vortrag
Donnerstag, 30. März 2006, 17:45–18:00, HSZ 03
Magnetic domains and spin structure in single-crystalline NiMn/Co bilayers on Cu(001) — •Carsten Tieg1, Radu Abrudan1,2, Matthias Bernien2, Wolfgang Kuch2, and Jürgen Kirschner1 — 1Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle — 2Freie Universität Berlin, Institut für Experimentalphysik, Arnimallee 14, 14195 Berlin
The magnetic domain structure in epitaxial single-crystalline bilayers of antiferromagnetic NiMn and ferromagnetic Co on Cu(001) was studied by photoelectron emission microscopy using the element selective x-ray magnetic circular dichroism as a contrast mechanism. We observed that the Co domain structure changes from a large domain configuration into a small domain configuration as the thickness of the NiMn layer exceeds a critical thickness of 8–10 monolayer (ML) at T=300 K. The occurrence of small domains in the Co layer is attributed to the magnetic phase transition in the NiMn layer from para- to antiferromagnetic (AFM). The spin structure of NiMn deposited on magnetically saturated Co was investigated by x-ray magnetic linear dichroism (XMLD) spectroscopy. A non-vanishing XMLD signal was found at the Mn L3 absorption edge obtained from a 20 ML NiMn/6 ML Co/Cu(001) sample. This indicates a certain degree of collinearity of the Mn moments in the NiMn layer. The angular dependence of the XMLD signal suggests a non-bulk-like AFM spin structure of NiMn. The XMLD spectra can be explained by a small twist of the bulk AFM spin axes towards the Co magnetisation direction.