Possible martensitic transformation and ferrimagnetic properties in Heusler alloy Mn2NiSn

• It is found that the phase transition from austenite to martensite may happen at low temperature for Mn2NiSn with the Hg2CuTi-type structure.
• Both austenitic and martensitic Mn2NiSn are ferrimagnets.
• Martensitic transformation decreases the magnetization.

The electronic structure and magnetic properties of Hg2CuTi-type Mn2NiSn have been studied by performing the first-principle calculations. It is found that the phase transformation from the cubic to the tetragonal structure reduces the total energy, indicating that the martensitic phase is more stable and the phase transition from austenite to martensite may happen at low temperature for Hg2CuTi-type Mn2NiSn. Concerning the magnetism of Hg2CuTi-type Mn2NiSn, both austenitic and martensitic phases are suggested to be ferrimagnets. Furthermore, martensitic transformation decreases the magnetic moment per formula unit compared with austenitic phase. The results are helpful to accelerate the use of Mn2NiSn alloys in the series for magnetic shape memory applications.