Berlin 2005 – scientific programme

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MA: Magnetismus

MA 24: Oberfl
ächenmagnetismus

MA 24.2: Talk

Tuesday, March 8, 2005, 10:45–11:00, TU A060

The effect of chemical disorder on the empty electronic states of NiMnSb — •Jürgen Braun¹, Hristo Kolev¹, Georgi Rangelov¹, Markus Donath¹, Sven Borneman², Jan Minar², and Hubert Ebert² — ¹Physikalisches Institut, Westfälische-Wilhelms-Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster — ²Institut für Physikalische Chemie, Ludwig-Maximilians-Universität München, Theresien Str. 37-41, 80333 München

The empty electronic states of the half-metallic semi Heusler alloy NiMnSb have been investigated by spin-resolved Appearance Potential Spectroscopy (SRAPS). Compared to fully relativistic SRAPS calculations our measurements reveal an unexpected low spin-polarization. To understand the physical origin of this discrepancy we performed a quantitative theoretical analysis of the influence of chemical disorder on the unoccupied density of states (DOS). Our theory describes the spectra as the self-convolution of the matrix-element weighted, orbitally-resolved unoccupied DOS, which was calculated by use of the ab-initio Coherent Potential Approximation (CPA) method.