Effect of electron localization in theoretical design of Ni-Mn-Ga based magnetic shape memory alloys
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Date
2021-06-19
Authors
Zelený, Martin
Sedlák, Petr
Heczko, Oleg
Seiner, Hanuš
Veřtát, Petr
Obata, Masao
Kotani, Takao
Oda, Tatsuki
Straka, Ladislav
ORCID
0000-0001-6715-4088Advisor
Referee
Mark
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
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Abstract
The precise determination of the stability of different martensitic phases is an essential task in the successful design of (magnetic) shape memory alloys. We evaluate the effect of electron delocalization correction on the predictive power of density functional theory for Ni-Mn-Ga, the prototype magnetic shape memory compound. Using the corrected Hubbard-model-based generalized gradient approximation (GGA+U), we varied the Coulomb repulsion parameter U from 0 eV to 3 eV to reveal the evolution of predicted material parameters. The increasing localization on Mn sites results in the increasing stabilization of 10M modulated structure in stoichiometric Ni2MnGa in agreement with experiment whereas uncorrected GGA and meta-GGA functional provide the lowest energy for 4O modulated structure and nonmodulated structure, respectively. GGA+U calculations indicate that 10M structure is more stable than other martensitic structures for U > 1.2 eV. The key features of density of states (DOS) responsible for the stabilization or destabilization of particular martensitic phases calculated with GGA+U are found also in DOS calculated with advanced quasi-particle self-consistent GW (QSGW) method. It supports the physical background of Hubbard correction. Moreover, the calculations with U = 1.8 eV provide the best agreement with experimental data for lattice parameters of stoichiometric and off-stoichiometric alloys. (C) 2021 The Authors. Published by Elsevier Ltd.
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Citation
Materials & Design. 2021, vol. 209, issue 1, p. 109917--.
https://www.sciencedirect.com/science/article/pii/S0264127521004706
https://www.sciencedirect.com/science/article/pii/S0264127521004706
Document type
Peer-reviewed
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Published version
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en