Dresden 2026 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 13: Magnetic Heuslers and Semiconductors
MA 13.2: Vortrag
Montag, 9. März 2026, 15:15–15:30, POT/0361
Impact of disorder on magnetic and vibrational properties of Ni-Mn-Sn Heusler alloys — •Olga Miroshkina1, Benedikt Eggert1, Benedikt Beckmann2, Franziska Scheibel2, Katharina Ollefs1, Oliver Gutfleisch2, Heiko Wende1, and Markus E. Gruner1 — 1University of Duisburg-Essen, Duisburg, Germany — 2Technical University of Darmstadt, Darmstadt, Germany
Ni-Mn-Sn Heusler alloys are attractive candidates for multi-stimuli caloric cooling. They undergo a magneto-structural phase transition at temperature that can be tuned via chemical disorder. In this work, we investigate the austenitic and martensitic phases near the composition Ni50Mn35Sn15 by means of density functional theory complemented by magnetometry and nuclear resonant inelastic x-ray scattering (NRIXS). Bain-path calculations reveal strong competition between ferro-(FM) and ferrimagnetic (FiM) states in austenite and a clear FiM configuration in the L10 martensite. The FiM contribution in the cubic phase is confirmed by comparing the calculated Sn vibrational DOS with that extracted from NRIXS. In martensite, frustrated exchange introduced by Mn excess can prevail in the tetragonal FiM L10 phases and make nano-twinns competitive. We find that twins constructed according to the continuum theory of martensite are energetically even more favorable than L10. A striking outcome is that all Mn/Sn-disordered configurations are energetically more favorable than the ordered ones, with the FiM 4O and 10M phases remaining the most competitive structures. Financial support within the DFG Projects MI 3273/1 and CRC/TRR 270 is gratefully acknowledged.
Keywords: Heusler alloys; magnetic disorder; chemical disorder; vibrational DOS; martensitic transformation