LAUSR

Abstract Crystal structure, magnetism, martensitic transition, electronic structure and mechanical properties of Heusler compounds Mg2YZ (Y = Sc, Ti, V, Z = Al, Ga, In) were studied by carrying out first-principles calculations based on density functional theory. All compounds in the cubic phase have an inverse Heusler structure with Hg2CuTi as the prototype. Mg2ScZ is paramagnetic and does not undergo a martensitic transition, while Mg2Ti(or V)Z undergoes a martensitic transition and shows ferromagnetism, which is basically unchanged (or smaller) with the phase transition. Y and Z atoms play major and minor roles, respectively, in the electronic structure, which directly affects the magnetism of the two phases. The calculated mechanical properties indicate that Mg2TiZ is ductile in the cubic phase and brittle in the tetragonal phase, while Mg2VZ has a similar brittleness in both the cubic and tetragonal phases. It is predicted that Mg2TiZ and Mg2VAl (or Ga) are prone to tetragonal distortion.