Mechanical, electronic structure, magnetic properties, and strain effects of quaternary Heusler alloy FeMnZnZ (Z = Si, Ge, Sn, Pb)

In this study, the electronic structure and mechanical and magnetic properties of quaternary Heusler alloy FeMnZnZ (Z = Si, Ge, Sn, Pb) were analyzed through first-principles calculations. The electronic band and density of the state of FeMnZnSi and FeMnZnGe indicated that they are half-metallic with an indirect and direct band gap of 0.329 and 0.342 eV, respectively. The magnetic moments derived from magnetic calculations suggested that both alloys satisfied the Slater–Pauling rule of M_t = Z_t - 28 with a total magnetic moment of 3 µB. Moreover, the effects of the uniform strain of the lattice constant on the half-metallicity of alloys were analyzed. The lattice constants of FeMnZnSi and FeMnZnGe exhibited half-metallic properties ranging from − 5 to 21% and − 13 to 14%, respectively. Furthermore, after using Si as the lattice constant, FeMnZnZ (Z = Sn, Pb) exhibited a magnetic moment of 3 µB, which satisfied the Slater–Pauling rule of M_t = Z_t - 28, and demonstrated half-metallic properties. Finally, the relationship between the changes in the total magnetic moment, atomic magnetic moment, half-metallic band gap, and lattice constant of this series of half-metallic alloys was examined. (author)