Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 64: Poster 1

MA 64.24: Poster

Freitag, 24. März 2017, 09:30–13:00, P2-EG

Spin disorder effect on the electronic properties of NiMnSb — •Roman Kováčik, Phivos Mavropoulos, and Stefan Blügel — Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, 52425 Jülich, Germany

An important contribution to the spin-caloric transport properties in magnetic materials at elevated temperatures is the formation of a spin-disordered state due to the local moment fluctuations. We investigate how the spin disordered state affects the spectral function, self energy and transport properties of NiMnSb, a prototypical half-metallic ferromagnet. The electronic structure of NiMnSb is calculated within the full-potential Korringa-Kohn-Rostoker (KKR) Green function framework [1]. The Monte-Carlo methodology is used to simulate the effect of temperature induced spin disorder and the set of spin-disordered configurations is fed back in the KKR method to obtain statistical average of the relevant material properties [2]. As an example, we find qualitative differences between the spectral function projected on Ni and Mn sites around the Curie temperature. In comparison to the T=0 K state, the majority spin spectral function only broadens at Ni site whereas it acquires rather rich landscape at Mn site. In the minority spin, the most interesting outcome is the shift of the prominent peak away from the Γ-point at Ni site and to higher energy across the Fermi level at Mn site. Support from the DFG (SPP 1538) and JARA-HPC (jara0051) is gratefully acknowledged. [1] N. Papanikolaou et al., J. Phys. Condens. Matter 14, 2799 (2002), also see: www.kkr-gf.org. [2] R. Kováčik et al., Phys. Rev. B 91, 014421, (2015).