Berlin 2024 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 16: Poster Ia

MM 16.4: Poster

Monday, March 18, 2024, 18:30–20:30, Poster E

Ab initio study of phase stability of YMn2 with different magnetic orderings — •Pavel Papež, Martin Friák, and Ilja Turek — Institute of Physics of Materials, Czech Academy of Sciences, Žižkova 22, Brno, 616 00, Czech Republic

Our work is focused on the intermetallic compound YMn2 which exhibits an anomalous thermal expansion. The origin of this phenomenon is belived to be magnetism-related but it is not completely understood yet. A puzzling aspect is e.g. a 5% volume change at the Neél temperature of 100 K. We have employed quantum-mechanical calculations to examine the thermodynamic stability of different magnetic states. Our calculations included non-collinear magnetic states which were defined employing the spin-orbit coupling. The computational cell was that of the C15 Laves phase and contained 24 atoms. The 7 different magnetic configurations were set up along the [0 0 1] direction. Our results show the most stable configuration is an antiferomagnetic (AFM) state which is followed closely by two experimentally reported configurations with the same AFM nearest neighbour configurations but pointing along different directions. Interestingly, these two magnetic configurations exhibit very similar energies. Importantly, the resulting magnetic moments on Mn atoms and lattice parameters show very good agreement with the values reported in previous experimental studies.

Keywords: ab-initio; VASP; Magnetic configurations; YMn2; Energy-volume curves