Phase stability and magnetic properties of Ni_50-xCu_xMn₃₁Ga₁₉ alloys

The phase stability and magnetic properties were studied in Ni_50-xCu_xMn₃₁Ga₁₉ (x = 0-4) alloys where Ni atoms were partially substituted by the non-ferromagnetic Cu atoms. The martensitic transformation temperatures decreased with the increasing Cu content. The stability of the austenite was well favored by the substitution of Cu for Ni. More interestingly, the ferromagnetic ordering temperature T_C was increased by the substitution of the non-ferromagnetic Cu atoms for the ferromagnetic Ni atoms. Simultaneously, the ferromagnetism of both the austenite and martensite was enhanced by Cu addition.