Berlin 2008 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 13: Surface Magnetism
MA 13.5: Vortrag
Dienstag, 26. Februar 2008, 11:30–11:45, EB 301
Ab-initio simulation of magnetic exchange force microscopy of antiferromagnetic Fe/W(001) — •Cesar Lazo1, Vasile Caciuc2, Hendrik Hölscher3, and Stefan Heinze1 — 1Institute of Applied Physics, University of Hamburg, Hamburg, Germany — 2Institute of Physics, University of Münster, Germany — 3Center for Nanotechnology, University of Münster, Germany
Magnetic exchange force microscopy (MExFM) is a promising new technique to perform magnetic imaging with atomic resolution by measuring the magnetic exchange force between a magnetically coated tip and a magnetic sample [1]. Here, we apply density functional theory using the full-potential linearized augmented plane wave (FP-LAPW) method to investigate the exchange forces on the antiferromagnetic monolayer Fe on W(001) [2]. We use an Fe cluster as a tip model and include relaxations of the cluster and the surface. Interestingly, relaxation effects of tip and sample depend sensitively on the local magnetic configuration. Therefore, relaxations play a crucial role for the magnetic signal. In particular, the onset of the exchange forces is shifted to larger distances, which facilitates their experimental observation. Based on the calculated force-distance curves we simulate MExFM images which display a competition of chemical and magnetic forces.
[1] U. Kaiser et al., Nature 446, 522 (2007).
[2] A. Kubetzka et al., Phys. Rev. Lett. 94, 087204 (2005).