Regensburg 2007 – scientific programme

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DS: Fachverband Dünne Schichten

DS 15: Poster Session

DS 15.20: Poster

Tuesday, March 27, 2007, 15:00–17:00, Poster B

Relaxation effects in NiMnSb-Half-Heusler thin films — •Andreas Stahl, Christian Kumpf, and Eberhard Umbach — Universität Würzburg, Experimentelle Physik II

Due to its unusual half-metallic properties the Half-Heusler alloy NiMnSb is an important material which may be utilized for the fabrication of spintronic devices. It can be grown in high crystalline quality on InGaAs/InP substrates, however, as for all heteroepitaxial systems mechanical stress is an important factor which influences crystalline quality, film growth, and magnetic properties. One example is a magnetic anisotropy which depends on the thickness of the Half-Heusler layer [1].

It turned out that the properties of the NiMnSb layers are strongly influenced by air. Therefore we present results from two series of samples, one with, the other without an amorphous Au/Ti cap layer. Reciprocal space mapping and x-ray reflectivity measurements were performed at the six-circle-diffractometer at BW2, HASYLAB, Hamburg. Structural properties like the critical thickness for pseudomorphic growth, relaxation, interface roughnesses, and the influence of the capping on these parameters are discussed.

[1] A. Koveshnikov et al.: J. Appl. Phys. 97, 073906 (2005).