Regensburg 2019 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 53: Magnetic Heuslers, half-metals and oxides

MA 53.2: Vortrag

Freitag, 5. April 2019, 09:45–10:00, H33

Designing rare-earth free permanent magnets with tetragonally distorted Heusler compounds by light interstitials — •Qiang Gao, Ingo Opahle, and HongBin Zhang — Institute of Materials Science, TU Darmstadt, 64287 Darmstadt, Germany

Permanent magnets are crucial materials for energy harvesting and conversion.[1] Rare-earth (RE) based magnets with good performance are subjected to criticality and environmental issues, resulting in great need for RE free magnets. To this goal, we explore the possibility of engineering permanent magnets based on Heusler compounds with transition metals. Starting from the known stoichiometric L2₁ Heusler compounds, we investigated the effect of light interstitial H, B, C, and N atoms. It is observed that the interstitials will occupy the octahedral holes, leading to effective tetragonal distortion and hence enhanced magnetocrystalline anisotropy. The uniaxial magnetic anisotropy energy can be as large as 1.43 MJ/m³ for Ni₂FeGa with N interstitial, of which the value is three times larger than that of the same tetragonal distortion for Ni₂FeGa without interstitials. Detailed analysis based on the Bruno’s model[2] reveals that the local distortions around the interstitials play an important role. [1] O. Gutfleisch, M.A. Willard, E. Bruck, C.H. Chen, S.G. Sankar, J.P. Liu, Adv. Mater. 23, 821 (2011). [2] P. Bruno, Phys. Rev. B 39, 865 (1989).