Berlin 2015 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 3: Magnetic Heuslers, Half-metals and Oxides (jointly with TT)

MA 3.8: Vortrag

Montag, 16. März 2015, 11:30–11:45, H 0112

Ab initio study of tetragonal Heusler alloys for magnetic applications with high anisotropies — •Heike C. Herper, Yaroslav O. Kvashnin, and Olle Eriksson — Department of Physics and Astronomy, Uppsala University, Sweden

Materials with high magnetic anisotropy (MAE) are of broad technological interest whereby typical magnets with high MAE are based on expensive materials such as Pt or Nd. Therefore, cheap and abundant replacements are demanded. Heusler alloys are of special interest because their magnetic and structural properties can be quite easily designed by composition. Here we present an ab initio study for a series of tetragonal Ni-based Heusler alloys Ni₂YZ with (Y = Mn, Fe, Co) and Z varying from B to Sn. Combined VASP and RSPt investigations reveal MAE values for L2₁ ordered Co containing alloys which are comparable to the Mn-Ga based alloys found in literature. However, for e/a values larger than 32 they tend to inverse order which is accompanied by a significant reduction of the MAE. Even though the MAE values for alloys with Y = Fe are found to be smaller compared to the Ni₂CoZ alloys, the maximum energy products are similar. In contrast to the L2₁ ordered Ni₂CoZ systems out of plane MAE has been observed for several Ni₂FeZ alloys.