Ferromagnetic phase nucleation and its growth evolution in FeRh thin films

• The relaxation of magnetization in thin FeRh films has been studied during phase transition. • A phenomenological model that describes the evolution of the phase transition in thin-film FeRh systems has been constructed. • Phase transition dependence on the initial state of the system is demonstrated. • A new approach to the interpretation of TFORC diagrams is proposed. The process of the nucleation and evolution of the ferromagnetic phase in the thin Fe 49 Rh 51 film on a MgO substrate near the phase transition from the antiferromagnetic (AFM) to the ferromagnetic (FM) state was comprehensively characterized by means of measurements of the temperature, time and magnetic field dependences of the magnetization. The observed relaxation processes of magnetization indicate the nucleation of the FM phase on the film surface and its further growth towards the film-substrate interface upon heating or applying the external magnetic field. The confirmation and verification of the FM phase growth evolution were carried out by the methods of vibrational magnetometry and magnetic force microscopy. A phenomenological model described the evolution of the FM phase growth in thin films based on the Bean-Rodbell and Kolmogorov-Johnson-Mehl-Avrami (KJMA) models is proposed. The article presents a new approach for interpreting Temperature First Order Reversal Curve (TFORC) diagrams based on comparative analysis of the coercivity and squareness coefficient temperature dependences and the peak position on the diagram.