Elucidation of microstructures produced in Ni₅₁Fe ₂₂Ga₂₇ ferromagnetic shape memory alloy

Both the magnetic and crystallographic microstructures in the ferromagnetic shape memory alloy Ni₅₁Fe₂₂Ga₂₇ were extensively studied by electron holography, electron diffraction, dark-field image observations, and the phenomenological crystallographic theory of martensitic transformations. This study elucidated anomalies that were observed in the magnetic flux pattern before the onset of the martensitic transformation. Furthermore, the observations clarified the relationship between the magnetization vectors and the shape strain directions in the martensite variants that formed a self-accommodation group.