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O: Fachverband Oberflächenphysik

O 16: Scanning probe methods I

O 16.6: Vortrag

Montag, 14. März 2011, 16:15–16:30, WIL C307

Magnetic Exchange Force Spectroscopy on antiferromagnetic Fe/W(001) — •Rene Schmidt¹, Cesar Lazo², Alexander Schwarz¹, Stefan Heinze², and Roland Wiesendanger¹ — ¹Institute of Applied Physics, University of Hamburg — ²Institute of Theoretical Physics and Astrophysics, University of Kiel

With the invention of magnetic exchange force microscopy (MExFM)[1] a new powerful tool to investigate atomic scale magnetic structures on all kinds of surfaces became available. Recently, we were able to resolve the antiferromagnetic structure of the Fe monolayer on W(001)[2]. Here, we demonstrate that it is possible to directly measure the distance dependence of the magnetic exchange interaction across a vacuum gap by applying a spectroscopic mode, i.e. magnetic exchange force spectroscopy (MExFS). Experimentally acquired data are compared with first-principles calculations accounting for magnetically different tips composed of Cr, Fe or mixtures of both. While sign and magnitude of the magnetic exchange energy are well reproduced, the majority of tips exhibit a stronger distance dependence than predicted for simple pyramidal tips and a more sudden onset of the interaction. More complex tip models will be discussed, which can explain this behavior.

[1] U.Kaiser et al., Nature 446, 522 (2007)

[2] R. Schmidt et al., Nano Lett. 9, 200 (2009)