Structural, electronic, elastic and mechanical properties of novel ZrMnAs half-Heusler alloy from first principles

Omosede Osafile, Federal University of Petroleum Resources, Effurun, Warri, Nigeria
Judith Azi, Federal University of Petroleum Resources, Effurun, Warri, Nigeria

The search for 100% spin polarized alloys for applications in spintronic devices is far from saturated, seeing the influence of other properties of the materials under investigation such as the generalized Slater-Pauling behavior, half metallic behavior, and the effect of crystalline ordering and more, renders many half Heusler (HH) alloys inefficient for application in spintronics.

We report the effect of Slater-Pauling behavior, half metallicity and crystalline ordering on the properties of three distinct phases of HH ZrMnAs (VEC = 16) alloy which are - [As (0, 0, 0), Mn (0.5, 0.5, 0.5), Zr (0.25, 0.25, 0.25)] phase, - [Mn (0, 0, 0), Zr (0.5, 0.5, 0.5), As (0.25, 0.25, 0.25)] phase and - [As (0, 0, 0), Zr (0.5, 0.5, 0.5), Mn (0.25, 0.25, 0.25)] phase. With emphasis on effect of the interaction of magnetic-rich Mn at all possible Wyckoff positions, the most stable phase in the face of the three properties checked is the - phase with Mn at the 0.25 tetrahedral site as a cation. However, the - phase shows a stable half metallic behavior even when subjected to a hydrostatic pressure of + or - 0.5 a.u. and has a magnetization of 2 µβ in line with the Slater-Pauling rule for half metallic materials with a half metallic band gap of 1.4eV. The electronic structure calculation reveals a semiconducting band gap in the majority band and a metallic behavior in the minority band of the alloy. Confirming a half metallic character in the - phase of the alloy hence, presenting it as a good candidate for spintronic devices. The - and - phases have B/G ratios of 4.364 and 4.518 respectively as against the critical value of 1.75 showing they are ductile materials.

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