Ni-Mn-Ga Ferromagnetic Shape Memory Alloy (FSMA) has been prepared by melt casting
technique. The alloy was annealed at different temperatures. The samples are characterized in
prepared condition and after three different annealing treatments. Microstructure of the alloy has
been investigated using SEM at room temperature. Microstructure study reveals that the magnetic
domains run diagonally across the surface. Differential Scanning Calorimetry (DSC) result shows
the ferromagnetic transition temperature of the alloy is 105°C. In-situ study of structure during
heating has revealed that the martensite to austenite transformation takes place in the temperature
range of 28°C to 36°C. The present study focuses the effect of annealing on phase transformation
and magnetic transformation temperature of Ni-Mn-Ga alloy. It has been observed that the
thickness of the martensite plate increases as the alloy is annealed at 950°C for 30 hrs.
Observations of Magnetic Domains in a Ni51Fe22Ga27 Ferromagnetic Shape Memory Alloy by Electron Holography