Effect of heating/cooling rate on martensitic transformation of NiMnGa-Co high temperature ferromagnetic shape memory alloys

Ni56Mn(25-x)Ga19Cox (x = 0, 2, 4 at.%) ferromagnetic shape memory alloys were fully annealed and then prepared according to different thermal routes. It was found that a quench process, together with a high heating rate, improves the thermal response and stabilizes the thermo-elastic transformation in Co-doped samples; in addition, it was observed that a low-rate thermal cycling is comparable to an austenitic aging.