Regensburg 2022 – scientific programme

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MA: Fachverband Magnetismus

MA 32: Bulk Materials: Soft and Hard Permanent Magnets

MA 32.3: Talk

Thursday, September 8, 2022, 15:30–15:45, H43

Effects of disorder on the magnetic properties of L1₀-FeNi — Ankit Izardar and •Claude Ederer — ETH Zürich, Switzerland

L1₀-ordered FeNi is a promising candidate for cheap mid-range permanent magnets. However, since the synthesis of fully ordered samples is very challenging, it is important to understand how deviations from perfect chemical order affect the magnetic properties of FeNi, in particular the magneto-crystalline anisotropy and Curie temperature. We use DFT in combination with a sampling over different supercell configuration to address effects of chemical disorder in FeNi. Our results show that a decrease in chemical order of up to 25 % does not cause a significant reduction of the magneto-crystalline anisotropy, and that the anisotropy can even be increased for Fe-rich compositions. We also show that the dominant magnetic coupling is strongly dependent on the specific chemical environment and vary drastically in the partially disordered system. We discuss these results in relation to alternative approaches to disorder, such as, e.g., the coherent potential approximation.