First-Principles Study on the Half-Metallicity of Half-Heusler Alloys: XYZ (X = Mn, Ni; Y = Cr, Mn; Z = As, Sb)

The electronic structures, magnetism, and half-metallicity of half-Heusler alloys XYZ (X = Mn, Ni; Y = Cr, Mn; Z = As, Sb) are investigated by means of the full-potential linearized augmented plane wave method within the generalized gradient approximation. We consider three types of atomic ordering (i.e., α, β, and γ phases for all of the alloys) and find that the α phase is energetically the most stable. From the calculated density of states and the total magnetic moments, we find that NiMnZ (Z = As, Sb) and NiCrAs are half-metallic ferromagnets, MnCrAs is a half-metallic antiferromagnet, and NiCrSb (MnCrSb) is almost a half-metallic ferromagnet (antiferromagnet).