Phase transformation of Heusler type Ni2+xMn1−xGa (x=0∼0.19)

Stoichiometric Ni2MnGa has a ferromagnetic and thermo-elastic martensitic transformation. Stoichiometric and non-stoichiometric Ni2+xMn1−xGa (x=0∼0.19) were made by the arc melting method and the martensitic and inverse martenistic transformation temperatues, Ms, Mf, As and Af, were measured by a differential scanning calorimeter. The phase transformation temperature, Tm, and the Curie temperature, Tc, were determined by the low field magnetic susceptibility vs. temperature curves. The Curie temperatures, Tc, decrease and the transformation temperatures, Ms, Mf, As and Tm (As), increase with an increase of Ni composition.