Regensburg 2010 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 31: Surface Magnetism / Magnetic Imaging II

MA 31.9: Vortrag

Donnerstag, 25. März 2010, 17:15–17:30, H23

Magnetic properties of Fe films on flat and vicinal Au(111): Consequences of the different growth behavior — •Tobias Allmers and Markus Donath — Physikalisches Institut, University of Münster, Germany

The epitaxial growth of Fe on flat Au(111) differs from Fe on vicinal Au(111). One consequence is a higher critical Fe overlayer thickness at which a phase transition from fcc(111) to bcc(110) takes place for Fe on vicinal Au(111) in comparison to flat Au(111) [1]. Accompanied with the structural phase transition is a spin-reorientation transition (SRT) of the easy magnetization direction from out-of-plane to in-plane. In agreement with the impeded phase transition an impeded SRT on vicinal Au(111) was observed. The SRT, however, proceeds in a narrow coverage range while the structural phase transition occurs gradually over a larger thickness range. A further consequence of the different growth behavior is a different topography for thicknesses beyond the phase transition. Fe on flat Au(111) exhibits a six-fold symmetry, Fe on vicinal Au(111) only a two-fold symmetry. The different symmetries influence the magnetic properties: While for bcc Fe(110) on flat Au(111) no easy magnetization direction could be determined, a preferred direction for Fe on vicinal Au(111) was identified which is perpendicular to the step edges. The two-fold symmetry causes an uniaxial magnetic behavior. This knowledge of the magnetization behavior is essential for correctly analyzing spin-resolved measurements of the electronic structure as demonstrated by photoemission measurements. [1] T. Allmers and M. Donath, New J. of Physics 11 (2009) 103049.