First-principles computation of structural, elastic and magnetic properties of Ni₂FeGa across the martensitic transformation

Author： Sahariah Munima B Ghosh Subhradip Singh Chabungbam S Gowtham S Pandey Ravindra

Publisher： IOP Publishing

ISSN： 0953-8984

Source： Journal of Physics: Condensed Matter, Vol.25, Iss.2, 2013-01, pp. : 25502-25508

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Abstract

The structural stabilities, elastic, electronic and magnetic properties of the Heusler-type shape memory alloy Ni₂FeGa are calculated using density functional theory. The volume conserving tetragonal distortion of the austenite Ni₂FeGa find an energy minimum at c/a = 1.33. Metastable behaviour of the high temperature cubic austenite phase is predicted due to elastic softening in the [110] direction. Calculations of the total and partial magnetic moments show a dominant contribution from Fe atoms of the alloy. The calculated density of states shows a depression in the minority spin channel of the cubic Ni₂FeGa just above the Fermi level which gets partially filled up in the tetragonal phase. In contrast to Ni₂MnGa, the transition metal spin-down states show partial hybridization in Ni₂FeGa and there is a relatively high electron density of states near the Fermi level in both phases.