Site preference and electronic structure of Mn₂RhZ (Z = Al, Ga, In, Si, Ge, Sn, Sb): a theoretical study

The electronic structure and magnetism of Mn₂RhZ (Z = Al, Ga, In, Si, Ge, Sn, Sb) Heusler alloys have been studied by using first-principles calculations. Three half-metallic ferromagnets, namely, Mn₂RhAl, Mn₂RhGe and Mn₂RhSb have been considered. The calculated equilibrium lattice constant increases with increasing atomic number of Z atoms lying in same column of periodic table. The calculated total magnetic moments M_tot are 2 µ_B/f.u. for Mn₂RhAl and Mn₂RhGa, 3 µ_B/f.u. for Mn₂RhSi, Mn₂RhGe and Mn₂RhSn, and 4 µ_B/f.u. for Mn₂RhSb, which agrees with the Slater-Pauling curve quite well. In all these compounds, except for Mn₂RhSb, the moments of Mn (A) and Mn (B) are antiparallel to each other. The total magnetic moments of the three considered half-metals assume integral values in a wide range of equilibrium lattice parameters.