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

Abstract

The structural stabilities, elastic, electronic and magnetic properties of the Heusler-type shape memory alloy Ni(2)FeGa are calculated using density functional theory. The volume conserving tetragonal distortion of the austenite Ni(2)FeGa 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 Ni(2)FeGa just above the Fermi level which gets partially filled up in the tetragonal phase. In contrast to Ni(2)MnGa, the transition metal spin-down states show partial hybridization in Ni(2)FeGa and there is a relatively high electron density of states near the Fermi level in both phases.

Correlation between phonon anomaly along [211] and the Fermi surface nesting features with associated electron-phonon interactions in Ni2FeGa: A first principles study

“…This can be expected as we do not see any phonon anomaly in our above calculations on phonon spectrum in the martensite phase. Moreover, this point is further supported by our previous calculations on electronic structure where we find the density of states (DOS) in the austenite phase to be much larger than the DOS in the martensite phase at the Fermi level [24]. As it is observed in our previous calculations that the downspin electrons are responsible for destabilizing the austenite phase, we cut the 3D Fermi surface of the austenite-downspin bands to get the 2D cross sections.…”

“…Optimized structural parameters from our previous work on Ni 2 FeGa have been used for both austenite and martensite phase calculations [24]. Fig.…”

“…All the calculations are done using the Quantum Espresso package [22,23]. The computational parameters are taken similar to our previous works on Ni 2 FeGa [24,25]. The Perdew-Burke-Ernzerhof (PBE) functionals [26] are used to address exchangeecorrelation interactions.…”

First-principle investigation of electronic structure, magnetism and phase stability of Heusler-type Pt2−Mn1+Ga alloys

“…Up to now, many investigations on the materials with the martensitic transformation have been done based on the first-principles calculations. The martensitic transformation and magnetic properties obtained based on these calculations are in good agreement with the experimental results [6][7][8][9][10][11][12][13]. Thus, the first-principles calculations have become an effective method to search for new-type FSMAs.…”

“…The driving force of Pt 1.5 Mn 1.5 Ga ( À 48.44 meV/atom) is the smallest. This value is considerably larger than the calculated driving force of Ni 2 MnGa [11], Mn 2 NiGa [13] and Ni 2 FeGa [11]. In addition, as listed in Table 1, for all the series, the c/a ratios are in the vicinity of 1.30.…”