Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 67: Poster 4

MA 67.28: Poster

Freitag, 24. März 2017, 09:30–13:00, P2-OG3

First Principles Calculations towards the Magnetic Phase Diagram of Quaternary Heusler Alloys — •Marianne Schröter, Anna Grünebohm, and Peter Entel — Universität Duisburg-Essen, Germany

Recently magnetic Heusler alloys have become of interest because of their giant inverse magnetocaloric effect and its desirous relevance for magnetic refrigeration[1]. Adding elements to the ternary Heusler alloys can tune the effect[2].

We investigate the influence of Cr and Co as quarternary elements on the magnetic phase diagram of NiMnGa. On the basis of DFT supercell calculations we look at the energy landscapes of theses alloys for different magnetic phases. KKR-CPA calculations together with subsequential Monte Carlo simulations highlight the degree of magnetic frustration in these systems. In the case of Cr for Ni substitution we see that energetically favoured are those states where the magnetic moments of Mn moments are ferromagnetically aligned. On the other hand the total magnetization is reduced by the antiferromagnetic alignment of Cr.

[1] K. A. Gschneidner et al., Rep. Prog. Phys. 68, 1479 (2005)

[2] V. V. Sokolovskiy et al., Phys. Rev. B 91, 220409(R) (2015)