Magnetic properties of ferromagnetic shape memory alloys Ni50+xMn12.5Fe12.5Ga25−x

The magnetic measurements on Ni50+xMn12.5Fe12.5Ga25−x (0 ≤ x ≤ 5.5) ferromagnetic shape memory alloys are made in the temperature range between 4.5 and 490 K. A phase diagram of Ni50+xMn12.5Fe12.5Ga25−x (0 ≤ x ≤ 5.5) alloys is determined from the results of the temperature dependence of the initial permeability. The Curie temperature, TC, decreases gradually with the concentration x. The martensitic and reverse martensitic transformation temperatures, TM and TR, increase with x and show a saturation behavior for x ≥ 3.0. The TM and TR of the sample with x = 4.5 were found to be 363 and 371 K, respectively.