Electronic Structure and Half-Metallicity in the Zr2RuZ (Z = Ga, In, Tl, Ge, Sn, and Pb) Heusler Alloys

The electronic structures, magnetic properties and half-metallicity in Zr2RuZ (Z = Ga, In, Tl, Ge, Sn, and Pb) alloys with AlCu2Mn- and CuHg2Ti-type structures were investigated using first-principles density functional theory (DFT) calculations. The calculations showed that Zr2RuIn, Zr2RuTl, Zr2RuSn, and Zr2RuPb compounds with CuHg2Ti-type structures were half-metallic ferromagnets with half-metallic band gaps of 0.18, 0.24, 0.22, and 0.27 eV, respectively. The half-metallicity originated from d-d and covalent hybridizations between the transition metals Zr and Ru. The total magnetic moments of the Zr2RuZ (Z = In, Tl, Sn, and Pb) compounds with CuHg2Ti-type structures were integer values of 1μB and 2μB, which is in agreement with Slater-Pauling rule (Mtot = Ztot − 18). Among these compounds, Zr2RuIn and Zr2RuTl were half-metals over relatively wide regions of the lattice constants, indicating that these two new Heusler alloys are ideal candidates for use in spintronic devices.