Berlin 2008 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 18: Poster Session I - MA 141/144 (Atomic Wires; Size-Selected Clusters; Nanostructures; Metal Substrates: Clean Surfaces+Adsorption of Organic / Bio Molecules+Solid-Liquid Interfaces+Adsorption of O and/or H; Surface or Interface Magnetism; Oxides and Insulators: Clean Surfaces)

O 18.46: Poster

Montag, 25. Februar 2008, 18:30–19:30, Poster F

Magnetic properties of thin Fe films grown on GaAs(110) in a two-step process — Lars Winking, Martin Wenderoth, •Swante Sievers, Jan Homoth, and Rainer G. Ulbrich — IV. Phys. Inst., Georg-August-Universität Göttingen

Thin Fe films grown on GaAs at room-temperature (RT) or above in general suffer from As outdiffusion and the formation of nonmagnetic compounds at the heterointerface [1]. To avoid such a interdiffused interface we deposited thin Fe films of up to 5 ML thickness on in-situ cleaved GaAs(110) at 130 K and subsequently annealed them within 2 hours to RT in the second step. At RT we studied the in-plane magnetic anisotropy (IPMA) of the Fe films in UHV by means of the Magneto-Optical Kerr Effect (MOKE). Most noticeable and in contrast to Fe films grown at RT or above is the presence of a clear hysteresis already at 3.5 ML film thickness as well as an IPMA in [001] [2]. Recent results on the LT growth of thin Fe films on GaAs(001) suggest that these properties are due to the suppression of As outdiffusion [1]. This is substantiated by the square hysteresis loops. The absence of gradual magnetization reversals indicates single domain Fe films nearly free of defects or precipitates [3]. From these experimental results we deduce that reactions at the heterointerface can be efficiently suppressed by the two-step growth process. This work was supported by the DFG-SFB 602 TP A7

[1] J.-M. Lee et al., PRB 76, 052406 (2007) [2] M. Gester et al., JAP 80, 347 (1996) [3] Y. Chye et al., APL 80, 449 (2002)