Dresden 2006 – scientific programme

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O: Oberflächenphysik

O 10: Semiconductor surfaces and interfaces

O 10.1: Talk

Monday, March 27, 2006, 15:00–15:15, PHY C213

Investigation of geometrical properties of NiMnSb-Half-Heusler thin films by X-ray reflectivity measurements. — •Andreas Stahl, Christian Kumpf, and Eberhard Umbach — Experimentelle Physik II, Universität Würzburg

The Half-Heusler alloy NiMnSb is an important material which may be utilized for the fabrication of spintronic devices due to it’s unusual half-metallic properties. 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].

We present a series of x-ray reflectivity measurements on MBE-grown NiMnSb thin films from 10nm to 200nm thickness. Some of the samples were capped with an amorphous Au/Ti layer in order to avoid oxidation in air. The reflectivity scans were performed at the six-circle-diffractometer at BW2, HASYLAB, Hamburg. We discuss important parameters like the layer thicknesses, the roughnesses of the interfaces and the electron densities of the Half-Heusler layers [2].

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

[2] A. Stahl et el.: to be published.