LAUSR

Abstract The structural, magnetic, and bulk mechanical properties of the full-Heusler alloys Pt2YZ (Y = Cr, Mn, Fe, and Co; Z = Ga, In, Ge, and Sn) were studied using first-principles calculations to explore new ferromagnetic shape memory alloys. All the alloys in the austenite phases have a ferromagnetic ground state, and among the alloys, the Pt2MnZ (Z = Ga, In, Ge, and Sn) has the largest total magnetic moment of almost 4.3 μB/f.u.. All the Pt2YZ compounds were found to be prone to undergo the martensitic phase transitions by analyzing the total energy difference Δ E between the austenite and martensite phases as well as the elastic constants of the austenite phases. The absolute values of the Δ E for these alloys are larger compared to the Ni2-based alloys, which implies that excess Pt can stabilize the martensite phase. Furthermore, the Pt2-based alloys have higher martensitic transition temperatures and better ductility than the Ni2-based alloys. Interestingly, four series Pt2YGa, Pt2YIn, Pt2YGe, and Pt2YSn exhibit the similar variation trends of the total moments, martensitic transition temperatures, and bulk mechanical properties with Y atom varying from Cr to Co.