First-principles study on electronic and mechanical properties of Ru₂XAl (X = Mn, Zr, Ti, Hf) alloys

The magnetic properties of Heusler alloys have been a hot research topic. However, the current understanding of the properties of Ru-based Heusler alloys is still very limited. The magnetic, electronic, and mechanical properties of four Ru-based Heusler alloys, Ru 2 XAl (X = Mn, Zr, Ti, and Hf) were calculated by the first-principles. This article studied the basic mechanical parameters of four types of Heusler alloys, such as bulk elastic modulus, Cauchy pressure, Pugh’s ratio, shear modulus, Kleinman parameter, Young’s modulus, Poisson’s ratio, and elastic constant. The calculated results of the elastic constant prove that all four alloys are mechanically stable. Ru 2 MnAl alloy exhibits brittleness, while the other three alloys exhibit excellent ductility based on Poisson’s ratio and Pugh’s ratio. The Kleinman parameter of the four alloys are all greater than 0.5, indicating that they have stronger stability in the tensile state. In addition, the spin magnetic moment of Ru 2 MnAl alloy is 2.113 μ B , which is consistent with the SP rule and other theoretical calculations.