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A First‐Principles Investigation of the Compositional Dependent Properties of Magnetic Shape Memory Heusler Alloys
Author(s) -
Siewert Mario,
Gruner Markus E.,
Hucht Alfred,
Herper Heike C.,
Dannenberg Antje,
Chakrabarti Aparna,
Singh Navdeep,
Arróyave Raymundo,
Entel Peter
Publication year - 2012
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201200063
Subject(s) - tetragonal crystal system , materials science , austenite , valence (chemistry) , valence electron , condensed matter physics , martensite , ab initio , diffusionless transformation , shape memory alloy , magnetic shape memory alloy , total energy , ab initio quantum chemistry methods , crystallography , thermodynamics , electron , metallurgy , magnetic domain , magnetic field , crystal structure , microstructure , magnetization , chemistry , physics , molecule , psychology , organic chemistry , displacement (psychology) , quantum mechanics , psychotherapist
The interplay of structural and magnetic properties of magnetic shape memory alloys is closely related to their composition. In this study the influence of the valence electron concentration on the tetragonal transformation in Ni 2 Mn 1 + x Z 1 − x (Z = Ga, In, Sn, Sb) and Co 2 Ni 1 + x Ga 1 − x is investigated by means of ab initio calculations. While the type of magnetic interaction is different for the two series, the trends of the total energy changes under a tetragonal transformation are very similar. We find that tetragonal structures become energetically preferred with respect to the cubic one as the valence electron concentration e / a is increased regardless of the system under consideration. In particular, the energy difference between the austenite and martensite structures increases linearly with e / a , which is in part responsible for the linear increase of the matensite transformation temperature. The substitution of nickel by platinum increases even further the transformation temperature.