Regensburg 2010 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 4: Magnetic Coupling Phenomena/ Exchange Bias
MA 4.4: Vortrag
Montag, 22. März 2010, 11:45–12:00, H22
Influence of ferromagnetic–antiferromagnetic coupling on the antiferromagnetic ordering temperature in Ni/FexMn1−x bilayers — •Miriam Stampe, Paul Stoll, Tobias Homberg, Kilian Lenz, and Wolfgang Kuch — Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
We present a detailed study on epitaxial bilayers made up of ferromagnetic (FM) Ni and antiferromagnetic (AFM) FexMn1−x layers. The AFM ordering temperature (TAFM) and the coupling at the interface of FM and AFM layer are deduced from polar magneto-optical Kerr effect measurements at different temperatures. The enhancement of coercivity for samples with different FexMn1−x layer thickness, Fe concentration and FM–AFM interface roughness reveals that TAFM only depends on the layer thickness. The FM–AFM coupling strength is determined by the Fe concentration of the FexMn1−x layer and the interface roughness, but as the measurement series clearly show, these do not affect the ordering temperature. The different behaviour of our out-of-plane measurements compared to earlier results for in-plane magnetization [1,2] leads us to the assumption that the spin structure in FexMn1−x is distorted from the 3Q structure in bulk material, depending on the magnetization direction of the adjacent FM layer.
[1] F. Offi et al., Phys. Rev. B 66, 064419 (2002).
[2] K. Lenz et al., Phys. Rev. Lett. 98, 237201 (2007).
Financial support by the DFG (KU1115/9-1) is acknowledged.