Dresden 2006 – scientific programme

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MA: Magnetismus

MA 35: Magnetic Thin Films V

MA 35.5: Talk

Friday, March 31, 2006, 11:45–12:00, HSZ 03

The effect of oxygen adsorption on the magnetization of Fe monolayers on (4×6) GaAs(001) — •Th. Kebe, Kh. Zakeri, J. Lindner, and M. Farle — Universität Duisburg-Essen

The absolute remanent magnetization of uncapped Fe monolayers grown on GaAs(100) [1] which have been exposed to oxygen doses up to 25000 Langmuir (pressures between 1×10⁻⁸ to 1×10⁻⁵ mbar) at RT were measured by in situ scanning SQUID magnetometry in UHV. The magnetization and the effect of the oxygen exposure could be monitored with sub monolayer sensitivity. The Fe films exhibit a thickness dependent surface roughness due to a Volmer-Weber growth which is largest for thinner layers. We find that 8 ML Fe still exhibit a ferromagnetic signal after 25000 Langmuir dosage, while the remanent magnetization disappears in a 5 ML Fe film at about 400 Langmuir already. The Fe oxide phase has been identified as Fe₂0₃ using Auger spectroscopy. Low temperature (T=40K) oxygen adsorption showed that the oxide formation of a 8 ML Fe film could be totally suppressed after chemisorption of a surface oxygen layer. Supported by DFG, Sfb 491.

[1] Kh. Zakeri et al., J. Magn. Magn. Mater. in press