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Thermal expansion, permeability and magnetization measurements of the ferromagnetic shape memory alloys, Ni 2 MnGa 0.88 Cu 0.12 , were carried out across the martensitic transition temperature T M and the reverse martensitic transition temperature T R at atmospheric pressure. When cooling from the austenite phase, a steep decrease in the thermal expansion due to the martensitic transition was found. The permeability indicates a sharp peak around T M and ferromagnetism below T M . Considering the permeability and magnetization results of Ni 2 MnGa 0.88 Cu 0.12 , the region above T M or T R is the paramagnetic-austenite phase and the region below T M or T R is the ferromagnetic-martensite phase. Magnetic phase diagrams were constructed based on the results of the temperature dependence of thermal expansion. T M and T R increased gradually with increasing magnetic field. The shift of T M in magnetic fields (B) around zero magnetic fields was estimated as dT M /dB = 1.3 K T −1 . The shift of T M indicates that magnetization influences the martensitic transition, and the increase of T M with magnetic field is proportional to the difference in the magnetization between the austenite and martensite phases.

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Thermal expansion, permeability, and magnetization measurements of ferromagnetic shape memory alloys, Ni 52 Mn 12:5 Fe 12:5 Ga 23 and Ni 2 Mn 0:75 Cu 0:25 Ga, were performed across the martensitic transformation temperature T M and the reverse martensitic transformation temperature T R . When cooling from austenite phase, a steep decrease in the thermal expansion due to the martensitic transformation was found for both alloys. Considering the permeability and magnetization results of Ni 2 Mn 0:75 Cu 0:25 Ga, the region above T M or T R is the paramagneticaustenite (Para-A) phase and the region below T M or T R is the ferromagnetic-martensite (Ferro-M) phase. Magnetic phase diagrams were constructed based on the results of the temperature dependence of thermal expansion. T M and T R increased gradually with increasing magnetic field. For Ni 52 Mn 12:5 Fe 12:5 Ga 23 and Ni 2 Mn 0:75 Cu 0:25 Ga, the shifts of T M in magnetic fields (B) were estimated as dT M =dB % 0:5 K/T and 1.2 T/K, respectively. The shifts of T M indicate that the that magnetization influences martensitic transition and the increase of T M in accordance with the magnetic fields is proportional to the difference between the magnetization of austenite phase with that of martensitic phase.

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