Structural characterization of half-metallic Heusler compound NiMnSb

High resolution X-ray diffraction (HRXRD) and Rutherford backscattering/channeling (RBS/c) techniques were used to characterize layers of NiMnSb grown by molecular beam epitaxy (MBE) on InP with a InxGa1-xAs buffer. Angular scans in the channeling mode reveal that the crystal structure of NiMnSb is tetragonally deformed with c/a=1.010±0.002, in agreement with HRXRD data. Although HRXRD demonstrates the good quality of the pseudomorphic NiMnSb layers the channeling studies show that about 20% of atoms in the layers do not occupy lattice sites in the [0 0 1] rows of NiMnSb. The possible mechanisms responsible for the observed disorder are discussed