Reversible control of magnetism in FeRh thin films

The multilayer of approximate structure MgO(100)/[ⁿFe₅₁Rh₄₉(63 Å)/⁵⁷Fe₅₁Rh₄₉(46 Å)]₁₀ deposited at 200 °C is primarily of paramagnetic A1 phase and is fully converted to the magnetic B2 phase by annealing at 300 °C for 60 min. Subsequent irradiation by 120 keV Ne⁺ ions turns the thin film completely to the paramagnetic A1 phase. Repeated annealing at 300 °C for 60 min results in 100% magnetic B2 phase, i.e. a process that appears to be reversible at least twice. The A1 → B2 transformation takes place without any plane-perpendicular diffusion while Ne⁺ irradiation results in significant interlayer mixing.