First-principle prediction of half-metallic properties for the Heusler alloys V2YSb (Y = Cr, Mn, Fe, Co)

The first-principle calculation within density functional theory is used to investigate the electronic structure and magnetism of the V2YSb (Y = Cr, Mn, Fe, Co) Heusler alloys with CuHg2Ti-type structure. Two half-metallic ferrimagnets (HMFs), namely, V2MnSb and V2FeSb, are predicted. The energy gap lies in the majority spin band for both V2MnSb and V2FeSb. The calculated total spin magnetic moments are −2μB per unit cell for V2MnSb, −1μB per unit cell for V2FeSb and zero for V2CoSb, which are in good agreement with the Slater–Pauling rule. For these alloys we studied, the magnetic moments of Y and V(A) are antiparallel to that of V(B) and all of these moments decrease with increasing atomic number of Y. We also found that the half-metallic properties of V2MnSb and V2FeSb are insensitive to the lattice distortion and a >90% spin polarization can be obtained within the wide range of 5.95–6.35 Å for V2MnSb, 5.8–6.25 Å for V2FeSb, respectively.