Critical phenomena in a two-dimensional ferrimagnetic system: Monte Carlo and Mean-Field Analysis.

The critical, first order, and spin compensation behaviors of a ferrimagnetic Ising system, consisting of spins S = 3 ∕ 2 and Q = 5 ∕ 2 alternating on a square lattice, have been studied by Monte Carlo (MC) simulations and Mean-Field Theory (MF). The system is defined by a Hamiltonian (H) that contains ferromagnetic next-nearest-neighbors interactions between S spins (J 2 ′) and Q spins (J 3 ′), as well as external magnetic field (h ′) and anisotropy (D 1 ′ , D 2 ′) interactions. The effects of D 1 ′ crystal and h ′ magnetic fields on the critical, double first order transition, and compensation phenomena are analyzed in detail. We found that the existence of a double first order phase transition depends on the temperature and the strength of h ′. • We calculate the finite temperatura diagrams of the magnetization of the model. • The system exhibits compensation temperatures and first order transitions. • We analyze the relation between critical, compensation and first order temperatures. • The compensation temperatures and first order transitions depends of h' and D ' 1. [ABSTRACT FROM AUTHOR]