Phase Stabilities and Magnetic Properties of Mn-Deficient and Ge-Substituted Mn3Ga With D022Structure

Abstract

We have investigated phase stabilities and magnetic properties of the tetragonal D022 phase in Mn-deficient Mn3– x Ga and Ge-substituted Mn3Ga1– y Ge y . A transition from the D022 to L10 phase is observed in the composition range of $x = 0.5$ –0.8 in Mn3– x Ga. On the other hand, the D022 phase is confirmed in the overall composition of Mn3Ga1– y Ge y . The thermal stability of the D022 phase strongly depends on the Ge content compared with the Mn deficiency. Magnetization of Mn3– x Ga is increased by introducing the Mn deficiency, whereas that of Mn3Ga1– y Ge y decreases with increasing Ge content despite a constant number of Mn atoms. This result suggests that the magnitude of magnetic moment of Mn atom in Mn3Ga1– y Ge y is influenced by variations of valence electron and structural properties caused by the Ge substitution.