The effect of the impurities on the magnetic, electronic and optical properties of Mn5Ge3

Earlier, we experimentally showed a significant effect of oxygen on the magnetic and structural properties of Mn₅Ge₃ due to the formation of a Nowotny phase of Mn₅Ge₃O_x. Here, in continuation of this study, we present a theoretical study of the magnetic and electronic properties of Mn₅Ge₃ and Mn₅Ge₃D_x (D = B, C, O). It was found that hexagonal Mn₅Ge₃ is a ferromagnetic metal with two nonequivalent manganese atoms in the structure. Our ab initio calculations also predict the existence of a spin-crossover in Mn₅Ge₃ under pressure. Impurities reduce saturation magnetization and electrical and thermal conductivity; however, the magnetic susceptibility and Curie temperature increase. Microscopic mechanisms of the effect of the impurities on the magnetic and electronic properties Mn₅Ge₃ are discussed.