Surface properties of ferromagnetic phase nuclei in the Fe₄₈Rh₅₂ alloy

Materials with a first-order magnetic phase transition demonstrate colossal changes in physical properties near the phase transition temperature. However, the mechanisms of phase transition occurrence are not fully understood. In this work, using the Fe₄₈Rh₅₂ alloy as an example, we study the near-surface magnetic and structural properties of the alloy near the phase transition temperature. Analysis of images obtained using the magneto-optic Kerr effect at different temperatures allowed us to separate the contributions from nucleation and growth of the ferromagnetic phase during the phase transition. Approximation of experimental data by the proposed model allowed us to estimate the surface energy of ferromagnetic clusters with different micromagnetic structures. The work also shows the influence of microscopic features on the formation of macroscopic properties of the alloy.