Dresden 2009 – scientific programme

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MA: Fachverband Magnetismus

MA 9: Surface Magnetism II

MA 9.4: Talk

Monday, March 23, 2009, 16:00–16:15, HSZ 403

fcc Co/Cu(001): Influence of the morphology on spin-dependent surface states and magnetic switching — •Tobias Allmers and Markus Donath — Physikalisches Institut, Universität Münster, 48149 Münster

The electronic structure and the magnetic properties of fcc Co films on Cu(001) are influenced by the morphology of the film. In our contribution we focus on surface states studied with spin-resolved direct and inverse photoemission and the magnetic reversal behavior studied with magneto-optical Kerr effect. The film morphology was controlled by the substrate temperature during film growth and subsequent annealing at various temperatures. The resulting differences in the film properties were additionally characterized with scanning tunneling microscopy. We found that the intensity of the occupied minority surface state with a binding energy of 0.4 eV [1] depends on the roughness of the surface. The spectral feature is very sharp and pronounced for a flat surface. The exchange-split unoccupied surface state at X-point is even more sensitive to the roughness of the surface. In addition, we observed that the film morphology influences the shape of the hysteresis curve. While a square-like hysteresis curve was observed for films with a smooth topography, the hysteresis curve for a rough Co surface reflects a more complex switching behavior of the magnetization.

[1] Schmidt et al., J. Phys. D 41 (2008) 164003