First-principles study of half-metallic properties for the Heusler alloys Sc2CrZ (Z = C, Si, Ge, Sn)

Abstract

First-principles calculations based on the density functional theory (DFT) for new Heusler compounds Sc2CrZ (Z=C, Si, Ge, Sn) were performed using the self-consistent full-potential linearized augmented plane wave (FPLAPW) method. It was predicted that the Sc2CrC compound in AlCu2Mn type structure is a non-magnetic metal, while it is a conventional ferromagnet in the CuHg2Ti structure. The Sc2CrZ (Z=Si, Ge, Sn) compounds were half-metallic ferrimagnets and conventional ferromagnets in the CuHg2Ti and AlCu2Mn type structures, respectively. The total magnetic moments of Sc2CrZ (Z=Si, Ge, Sn) compounds in the CuHg2Ti type structures were obtained 2μB per formula unit which were in agreement with Slater–Pauling rule (Mtot=18-Ztot). The majority spin gaps were calculated 0.72eV, 0.54eV and 0.52eV for Sc2CrSi, Sc2CrGe and Sc2CrSn in the CuHg2Ti type structure, respectively. In addition, the band structures and density of states (DOSs) were studied and the reason for appearance of majority band gaps in different compounds was also discussed. The Sc2CrSi, Sc2CrGe, and Sc2CrSn compounds in the CuHg2Ti type structure maintained their half-metallic characters for lattice constants range of 5.99–6.94Å, 5.89–6.71Å and 6.01–7.27Å, respectively, making them interesting materials in the spintronics field.