Dresden 2011 – scientific programme

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MA: Fachverband Magnetismus

MA 63: Poster II (Surface Magnetism/ Magnetic Imaging/ Topological Insulators/ Spin Structures and Magnetic Phase Transitions/ Graphene/ Magnetic Thin Films/ Magnetic Semiconductors/ Magnetic Half-metals and Oxides/ Spin-dependent Transport/ Spin Excitations and Spin Torque/ Spin Injection and Spin Currents in Heterostructures/ Spintronics/ Magnetic Storage and Applications)

MA 63.6: Poster

Friday, March 18, 2011, 11:00–14:00, P2

Modulation of magnetic anisotropy due to the quantization of Bloch states in ferromagnetic films on vicinal surfaces — Uwe Bauer, •Maciej Dabrowski, Marek Przybylski, and Jürgen Kirschner — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany

Oscillatory magnetic anisotropy is attributed to the quantization of Bloch states along the growth direction and the resulting formation of quantum well states (QWS). With varying film thickness, QWS lead to periodic changes in the electronic structure and therefore can modulate magnetic anisotropy.

To determine magnetic anisotropy by magneto-optic Kerr effect (MOKE), Fe thin films were grown on vicinal surfaces of Ag(001) and Au(001). The mono-atomic steps on the substrates induce an in-plane uniaxial anisotropy which determines the easy magnetization axis. Moreover, the magnetization can be tilted out of the film plane and result in an additional polar component to the Kerr signal which can result in hysteresis loops with a very complex shape. We provide a model, verified by experimental studies of Fe on Au(1,1,13), which explains why even small uncertainties in the experimental MOKE geometry can have a significant influence on the measured hysteresis loops.

The largest oscillation amplitude of Hs we obtained for Fe films grown on Ag(1,1,6). This shows that the larger the distorted fraction of the film volume (i.e. the larger the step density), the larger the amplitude of the anisotropy oscillations.