Mössbauer study of the martensitic transformation in a Ni–Fe–Ga shape memory alloy

We present the results of an extensive Mössbauer study of the magnetic and martensitic transformation at room temperature of a polycrystalline alloy with a Ni55Fe19Ga26 nominal composition. From calorimetric measurements, we have determined the martensitic transformation temperature of TM ≈ 240 K, in good agreement with the one obtained by magnetic characterization. This sample has a Curie temperature of TC ≈ 287 K. Additional Curie temperatures, belonging to a γ phase, have been also detected. Mössbauer spectroscopy performed at different temperatures monitored all these transformations and the fitting of the obtained spectrum at the highest temperature allow us to give percentages of the different phases in the sample.