Dresden 2017 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 17: Magnetic Heuslers, Half-Metals and Oxides (joint session MA, TT, organized by MA)

TT 17.7: Vortrag

Montag, 20. März 2017, 16:45–17:00, HSZ 403

Influence of grain boundaries on cohesive and magnetic properties in the inverse Heusler phase Fe₂CoGa
— •Georg Krugel, Daniel Urban, Wolfgang Körner, and Christian Elsässer — Fraunhofer Institute for Mechanics of Materials IWM, Wöhlerstraße 11, 79108 Freiburg, Germany

Heusler phases are promising candidates in the search for a rare-earth free hard-magnetic compound allowing high Curie temperatures. Experimentally, they are often found to be brittle and the effect of their microstructure on the material properties is not yet understood in detail.
Using DFT calculations we investigate the effect of grain boundaries (GB) on the mechanical and magnetic properties of the inverse Heusler phase Fe₂CoGa as a case study. Four different GBs are studied and several different translation states taken into account for each of them to sample the gamma surface. The GB excess volume, the formation energy of the GB and the cohesion energies of the grains are calculated and compared in order to shed more light onto the influence of GB on the mechanical properties of Heusler phases. For an understanding of the behaviour of magnetism at the GB the local atomic configurations are analysed together with the atomic magnetic moments. Moreover, we calculate the magnetic anisotropy energies for the energetically most favorable configurations. Our results support experimental efforts to determine tailored synthesis routes.