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MA: Fachverband Magnetismus

MA 42: Magnetic Heuslers, Half-Metals and Oxides (jointly with TT)

MA 42.2: Talk

Thursday, March 10, 2016, 09:45–10:00, H34

Influence of extended crystal defects on magnetic moments and magnetocrystalline anisotropy in the Heusler phase Fe₂CoGa — •Georg Krugel, Wolfgang Körner, Daniel F. Urban und Christian Elsässer — Fraunhofer Institute for Mechanics of Materials IWM, Wöhlerstr. 11, 79108 Freiburg, Germany

In the search for new and cheap rare-earth-free hard-magnetic materials, Heusler phases are promising candidates. Depending on their chemical composition, high Curie temperatures and high magnetizations without rare earth elements can be achieved. By using a computational screening approach, Gillesen et al. [1] identified several Heusler phases with high magnetic moments like Fe₂CoGa or Fe₂CoAl.

However, in order to have a good hard-magnetic material with a defined easy axis a substantial intrinsic crystalline anisotropy is needed. Unfortunately, the Heusler phases with high magnetic moment generally crystallize in the regular or inverse cubic structure with zero anisotropy. Nevertheless, extended crystal defects like stacking faults or grain boundaries may lead to preferred crystal orientations and provide a way for optimizing the magnetic anisotropy through microstructure engineering.

We present a density functional theory study on extended defects in Fe₂CoGa which illustrates how much magnetocrystalline anisotropy can be achieved. Furthermore, the impact of the extended defects on the local magnetic moments and the total magnetization is analyzed.

[1] M. Gillessen and R. Dronskowski, J. Comput. Chem. 30, 1290 (2009)