Influence of Co addition on martensitic and magnetic transitions in Ni-Fe-Ga β based shape memory alloys

Abstract

The effect of Co addition on the martensitic transition and magnetic properties of the Ni-Fe-Ga β alloys is investigated. The values of both the Curie temperature T c and martensitic transition starting temperature M s increase, while the saturation magnetization I s decreases with increasing Co content in the series of Ni 51Fe 22-XCo XGa 27 alloys. On the other hand, the values of both T c and I s increase and M s decrease with increasing Co content in the series of Ni 54-XFe 19Co XGa 27 alloys. T c and I s show a strong dependence on the average magnetic valence number Zm. Consequently, Co is an effective element to control both the martensitic and the magnetic transition temperatures. ©2005 The Japan Institute of Metals.