Comparative study of magnetic properties of a mixed spin-7/2 and spin-2 Ising system: Monte Carlo simulations vs mean-field theory

Abstract

The magnetic properties of the mixed-spin (7/2, 2) ferrimagnetic Ising System are systematically investigated using two complementary theoretical approaches: Monte Carlo simulations and mean-field theory. The system is composed of two interpenetrating face-centered cubic sublattices, hosting spin values of 7/2 and 2, respectively, coupled via ferrimagnetic exchange interactions. This study explores phase transitions, critical temperatures, and compensation points, with particular attention to the interplay between first- and second-nearest neighbor exchange interactions. A detailed comparative analysis reveals qualitative agreement between the two methods in predicting key features, such as the existence of compensation temperature and the second-order phase transition. However, notable quantitative discrepancies are observed in the predicted values of critical temperatures and the location of the compensation points, which are attributed to the inherent approximations of mean-field theory. We find that the compensation temperature T_comp emerges and remains constant once the next-nearest-neighbor interaction $J_3^{\prime }$ of the spin-S sublattice reaches a threshold value of 2.0. These findings not only underline the strengths and limitations of the employed methods, but also provides valuable insights into the complex magnetic behavior of mixed-spin systems.