Half-metallicity in the Inverse Heusler compounds Sc2MnZ (Z = C, Si, Ge, and Sn)

Abstract

Half-metallic properties of new Heusler alloys Sc2MnZ (Z = C, Si, Ge, and Sn) have been studied by first-principles calculations based on the density functional theory (DFT) using the self-consistent full-potential linearized augmented plane wave (FPLAPW) method. The results showed that the Sc2MnZ (Z = C, Si, Ge, and Sn) compounds in AlCu2Mn-type structure and Sc2MnC in CuHg2Ti-type structure are conventional ferrimagnets. The Sc2MnZ (Z = Si, Ge, and Sn) compounds were half-metallic ferrimagnets in the CuHg2Ti-type structure. In the CuHg2Ti-type structure, the calculated majority spin band gaps were 0.50 eV, 0.41 eV, and 0.26 eV for Sc2MnSi, Sc2MnGe and Sc2MnSn, respectively. The obtained total magnetic moments of Sc2MnZ (Z = Si, Ge, and Sn) compounds in the CuHg2Ti-type structures were 1 μB per formula unit which were in agreement with Slater–Pauling rule (Mtot = 18 − Ztot). In addition, the reason for appearance of half-metallic band gap in the Sc2MnGe compound was also discussed. The Sc2MnSi, Sc2MnGe, and Sc2MnSn compounds in the CuHg2Ti-type structure showed half-metallic characteristics at lattice constants ranges of 6.12–6.65 Å, 6.07–6.63 Å, and 6.18–6.81 Å, respectively, which make them interesting materials in the spintronics field.