Possibility of martensite transition in Pt-Y-Ga (Y=Cr, Mn, and Fe) system: An ab-initio calculation of the bulk mechanical, electronic and magnetic properties

Using first principles calculations based on density functional theory we have studied the effects of Fe and Cr doping at the Mn site on mechanical, electronic, and magnetic properties of Pt₂MnGa and Ni₂MnGa. We predict on the basis of formation energy that all the substituted X₂Mn_1-xY_xGa alloys (x=0.00, 0.25, 0.75, 1.00; X=Pt, Ni; Y=Fe and Cr) are stable materials. Further, all the substituted materials which we have studied here are likely to undergo martensite transition. In this work, we have reported how the stability of the austenite and martensite phase varies with the extent of substitution by Fe as well as Cr at the Mn site. Further, we study the bulk mechanical properties of the austenite and martensite phases of the stoichiometric systems only. We observe that Pt-based systems are inherently much less brittle in comparison to the Ni-based systems studied here. We also study the magnetic properties. Interestingly, contrary to the unsubstituted case as well as the case when Mn is substituted by Fe, the substitution by Cr at the Mn site leads to lowering of energy in case of an intra-sublattice anti-ferromagnetic configuration compared to the ferromagnetic configuration.