Martensitic transformation in Heusler alloys Mn2YIn (Y=Ni, Pd and Pt): Theoretical and experimental investigation

The martensitic transformation and electronic structure of Heusler alloys Mn2YIn (Y=Ni, Pd, Pt) have been investigated by both first-principles calculation and experimental investigation. Theoretical calculation reveals that, the energy difference ΔE between the tetragonal martensitic phase and cubic austenitic phase increases with Y varying from Ni to Pt in Mn2YIn. Thus a structural transition from cubic to tetragonal is most likely to happen in Heusler alloy Mn2PtIn. A single Heusler phase can be obtained in both Mn2PtIn and Mn2PdIn. A martensitic transformation temperature of 615 K has been identified in Mn2PtIn. And in Mn2PdIn, the austenitic phase is stable and no martensitic transformation is observed till 5 K. This indicates there may exist a positive relation between ΔE and martensitic transformation temperature. Calculated results show that Mn2YIn are all ferrimagnets in both austenitic and martensitic phases. The magnetic properties are mainly determined by the antiparallel aligned Mn spin moments. These findings can help to develop new FSMAs with novel properties.