Berlin 2012 – scientific programme

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MA: Fachverband Magnetismus

MA 33: Magnetic Coupling Phenomena/ Exchange Bias

MA 33.8: Talk

Wednesday, March 28, 2012, 17:15–17:30, EB 202

Exchange coupled Sm-Co/Fe thin films — •Martin Kopte, Simon Sawatzki, Christine Mickel, Darius Pohl, Alexander Surrey, Bernd Rellinghaus, Ludwig Schultz, and Volker Neu — Institut für Festkörper- und Werkstoffforschung Dresden

We present hard/soft magnetic tri- and fivelayered thin film stacks grown epitaxially by pulsed laser depostion (PLD), where the Fe layers are sandwiched in between highly uniaxial anisotropic Sm-Co layers [1]. With the total thickness of the Sm-Co layers remaining constant the exchange coupling effect in the fivelayered system is enhanced due to the larger number of Sm-Co/Fe interfaces, i.e. the maximum of the energy density product is shifted to larger Fe contents. Microstructural analysis by TEM/EELS confirms the intended film architecture, but also shows rough and diffused Sm-Co/Fe interfaces. The overall behaviour in the reversible part of the demagnetization can be simulated very well by a simple one-dimensional micromagnetic model [2]. The characteristic behaviour of the polarization, nucleation field and energy density product with varying Fe content is reproduced for both tri- and fivelayers. However, the irreversible switching field remains overestimated. An attempt to account for lateral domain processes in the model, which reduce this field, is made by introducing a defect with a pinning potential assigned to that occuring in single SmCo₅ layers.
[1] Sawatzki et al., Journal of Applied Physics 109, 123922 (2011)

[2] Kopte et al., IEEE Trans. Mag. 47, 3736 (2011)