Magnetic Properties, Possible Martensitic Transformation, and Elastic Properties of Heusler Alloy Fe 2 NiSb from First-Principles Calculations

The first-principles plane-wave pseudopotential method has been used to investigate the structural, magnetic, electronic and elastic properties of the Heusler alloy Fe 2 NiSb. It is found that the tetragonal phase of Fe 2 NiSb is more stable compared with the cubic phase from the energetic point of view. The martensitic transformation from a cubic to a tetragonal structure may happen with decreasing temperature. This phase transition is nearly volume-conserving, suggesting that this alloy is predicted to be a superior shape memory alloy. Fe 2 NiSb is found to be a ferromagnet. The saturation magnetization is 5.08 and 4.88 μ B/f.u. in the cubic and tetragonal phases, respectively. It is confirmed that Fe 2 NiSb displays an excellent ductile behavior by analyzing the ratio of bulk modulus to shear modulus. The calculated densities of states show that the peak splitting at the Fermi level decreases the total energy and is related to the stabilization of the tetragonal phase.