Regensburg 2007 – scientific programme

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O: Fachverband Oberflächenphysik

O 30: Nanostructures at Surfaces III (Dots, Particles, Clusters)

O 30.1: Talk

Tuesday, March 27, 2007, 15:45–16:00, H36

Co on Pt(111): from monolayer islands to single atoms — •Focko Meier, Kirsten von Bergmann, Paolo Ferriani, Jens Wiebe, Matthias Bode, Katsushi Hashimoto, Stefan Heinze, and Roland Wiesendanger — Institute of Applied Physics, Hamburg University, D-20355 Hamburg, Germany

We used spin-resolved scanning tunneling spectroscopy (STS) to study the electronic and magnetic properties of Co monolayer islands and single atoms on the Pt(111) surface.

Within the Co monolayer islands the local stacking changes at the scale of only a few Å. This results in a highly inhomogeneous electronic structure due to the strong stacking dependence of the d-like surface resonance with respect to the Pt(111) substrate.[1] A similar stacking dependence of the electronic structure has been found on the single atoms where spectroscopic differences are related to the two possible adsorption sites of the Co atoms on the Pt(111) substrate.

Despite the electronic inhomogeneity, the magnetic domains and domain walls are clearly observed by spin-resolved STS. New insights into the anisotropy K of the Co were found by analyzing the width of the domain walls. Based on our analysis we propose an out-of-plane anisotropy of +0.08 meV/atom -- +0.17 meV/atom for atoms within the islands which are out-of-plane magnetized, independently of their size.

[1] F. Meier et al. Phys. Rev. B 74, 195411 (2006)