Recrystallization and Magnetic Transition in FeRh Thin Films.

The recrystallization process in Fe51.2Rh48.8 thin films was studied to clarify the relationship between the film microstructure and the magnetic transition. It was found that high-temperature annealing results in grain growth and a plate-like structure. The transition temperature and the thermal hysteresis width decrease from 70 to 10°C and from 140 to 3°C, respectively, as the annealing temperature increases from 600 to 1200°C. The film annealed at 1200°C exhibits complete ferromagnetic-to-antiferromagnetic transition as bulk FeRh alloy does. The thin plate-like structure and the lattice distortion strongly affect the thermal hysteresis. It was found that the stress release mechanism is closely related to the thin plate martensitic transformation.