Regensburg 2010 – scientific programme

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MA: Fachverband Magnetismus

MA 18: Magnetic Thin Films II

MA 18.11: Talk

Wednesday, March 24, 2010, 18:00–18:15, H3

Spin Reorientation Transition of Co/Au(111) induced by ion bombardment — •Moritz Bubek, Sabine Pütter, and Hans Peter Oepen — Angewandte Physik, Universität Hamburg, Jungiusstr 11, 20355 Hamburg, Germany

Due to surface contributions ultrathin Co/Au(111) films exhibit large magnetic anisotropies perpendicular to the surface. A thickness driven spin reorientation transition (SRT) can be observed by increasing the film thickness. In magnetic susceptibility measurements a pronounced peak was found during Co growth indicating the reorientation from out-of-plane to in-plane orientation of the magnetization [1].

In our experiment we studied the magnetic susceptibility during Co removal by sputtering with 800 eV Ar ions. Starting with films of 6 monolayers thickness and in-plane easy axis of magnetization we can again drive the system into a spin reorientation to end up with a perpendicular magnetization orientation.

This is surprising as ion bombardment modifies the surface morphology and causes surface roughness that in general decreases the surface anisotropy [2]. To control the impact of the ion bombardment on the surface structure we used low energy electron diffraction. We discuss the magnetic origin of the peak and compare the film thickness of the SRT for Co growth and removal.

[1] S. Pütter et al., Phys. Rev. B 64, 092409, (2001)

[2] P. Bruno, J. Phys. F 18, 1291, (1988)