Site preference and tetragonal distortion of Heusler alloy Mn-Ni-V

Abstract Site preference, tetragonal distortion and phase stability of all d -metal Heusler alloys Mn 2-x Ni 1.5+x V 0.5 (x = 0, 0.5, 1), Mn 2-x Ni 1+x V (x = 0, 0.25, 0.5, 0.75, 1) and Mn 2-x Ni 0.5+x V 1.5 (x = 0, 0.5, 1, 1.5) are investigated. It has been found that Ni 2 MnV is stable in Hg 2 CuTi-type Heusler structure, while Mn 2 NiV tends to crystallize into Cu 2 MnAl-type Heusler structure. Mn atoms in both Ni-rich and Mn-rich Mn-Ni-V alloys preferentially occupy A, C sites, suggesting that the site occupation in Mn-Ni-V ternary alloy is not following the conventional site preference rule. A potential tetragonal distortion is expected in cubic structure of Ni-rich alloys MnNi 2 V, Mn 1.25 Ni 1.75 V, MnNi 2.5 V 0.5 and Mn 0.5 Ni 2 V 1.5 . It is found that the tetragonal distortion is mainly attributed to the decrease of intensity for DOS at the Fermi level in the minority spin direction which is caused by the splitting of peaks. This study will guide us to design new tetragonal Heusler materials for spintronic devices.