A quantum mechanical study of pressure induced changes of magnetism in austenitic \nstoichiometric Ni2MnSn

0552306 - ÚFM 2022 RIV DE eng A - Abstract
Friák, Martin - Mazalová, Martina - Turek, Ilja - Zemanová, Adéla - Kaštil, Jiří - Kamarád, Jiří - Míšek, Martin - Arnold, Zdeněk - Schneeweiss, Oldřich - Všianská, Monika - Zelený, M. - Kroupa, Aleš - Pavlů, J. - Šob, Mojmír
A quantum mechanical study of pressure induced changes of magnetism in austenitic
stoichiometric Ni2MnSn.
Programme and abstracts Intermetallics 2021. Magdeburg: Otto von Guericke Universität Magdeburg, 2021. s. 133-134. ISBN 978-3-948023-17-1.
[Internacional Conference Intermetallics 2021. 04.10.2021-08.10.2021, Kloster banz]
R&D Projects: GA MŠMT(CZ) LQ1601; GA MŠMT(CZ) LM2018096; GA ČR(CZ) GA20-16130S
Institutional support: RVO:68081723 ; RVO:68378271
Keywords : Ni2MnSn * quantum-mechanical * swaps * pressure * magnetism
OECD category: Condensed matter physics (including formerly solid state physics, supercond.); Condensed matter physics (including formerly solid state physics, supercond.) (FZU-D)

The Heusler alloys are one of the most prominent family of compounds currently studied due the presence of an extraordinary magneto-structural transition in their phase diagrams because this non-diffusive martensitic transition is accompanied nearly always by very pronounced changes of physical properties of the alloys. We have performed an ab initio study of a series of stoichiometric Ni2MnSn states with austenitic (full Heusler type) structure using 16-atom computational supercells. We have studied the effect of Mn-Ni, Mn-Sn and Ni-Sn swaps in the stoichiometric Ni2MnSn and we also compared states with both ferromagnetic (FM) and anti-ferromagnetic (AFM) coupling between (i) the swapped Mn atoms and (ii) the Mn atoms on the Mn sublattice for most of these atomic configurations (for some atomic configurations we were not able to stabilize them in our calculations). By analyzing the magnetic moments of states with swaps we show their complexity and significant influence on materials properties. In particular, they can lead to total magnetic moments twice smaller than those in the defect-free Ni2MnSn and pressure-induced changes in the total magnetic moment can be nearly three times larger but also smaller depending on the type of defects and the coupling of Mn atoms. Importantly, we find both qualitative and quantitative differences also in the pressure-induced changes of magnetic moments of individual atoms even for the same global magnetic state. Lastly, the FM-coupled and AFM-coupled states with very different magnetic properties have sometimes formation energies different only by a few meV per atom.
Permanent Link: http://hdl.handle.net/11104/0327466