Phase stability and magnetic-field-induced martensitic transformation in Mn-rich NiMnSn alloys

A series of Ni50-xMn41+xSn9 (x = 0–19) alloys from Ni-rich to Mn-rich composition were prepared, and the composition dependence of phase transitions and magnetic properties were investigated. No γ-phase can be observed until x = 17. Martensitic transformation from ferromagnetic austenite to weak-magnetic or ferromagnetic martensite was observed in alloys with Mn content between 52 and 58, and magnetic-field-induced transformation was confirmed. A large magnetization change of 44 Am2/kg across the martensitic transformation is observed in Ni37Mn54Sn9. Our results indicate that Mn-rich Ni-Mn-Sn alloys show promise as metamagnetic shape memory alloys.