Temperature induced A1 to B2 structural and magnetic transition in FeRh thin film

The Fe-Rh system offers a diverse range of magnetic phases, making it promising for energy-efficient magnetic devices. A periodic, chemically homogeneous, isotope-periodic ⁿFeRh/⁵⁷FeRh multilayer system was deposited on a MgO(100) substrate via molecular beam epitaxy, and annealed at various temperatures and durations. To gain deeper insights into the A1 to B2 structural and magnetic transitions, non-destructive techniques such as x-ray diffraction, conversion electron Mössbauer spectroscopy, and neutron reflectometry were employed. The qualitative and quantitative analysis revealed insights into the underlying mechanisms of the transformation from the A1 phase to the B2 phase were described, including the variation of the lattice parameters, grain sizes and hyperfine parameters. Neutron reflectometry revealed no significant long-range diffusion during the phase transition, suggesting a local interchange of neighbouring atoms.