Critical and compensation temperatures for the mixed spin-3/2 and spin-5/2 Ising model

Abstract

We have studied the critical and compensation temperatures of a ferrimagnetic Ising system with mixed spins $S_{i}^{A}$= $\pm 3/2, \pm 1/2$ and\linebreak $\sigma_{j}^{B}$ = $\pm 5/2, \pm 3/2, \pm 1/2$, by using Monte Carlo simulations. The spins are alternated on a square lattice, such that nearest neighbor interactions occur between different spins ($S_{i}^{A}\leftrightarrow\sigma_{j}^{B}$) and next nearest neighbors interactions between spins of the same type ($S_{i}^{A}\leftrightarrow S_{j}^{A}$). We investigate the effects of crystal field $D$ and the $J_{2}$ ferromagnetic coupling of spins $S_{i}^{A}$ on the critical and compensation temperatures of the system, calculating the phase diagrams at finite temperature at the ($D/|J_{1}|, k_{B}T/|J_{1}|$) and ($J_{2}/|J_{1}|, k_{B}T/|J_{1}|$) planes. When the Hamiltonian includes antiferromagnetic couplings between spins $S_{i}^{A}$ and $\sigma_{j}^{B}$, ferromagnetic between spins $S_{i}^{A}$ and the term of single ion anisotropy $D$, the system presents compensation temperatures in a certain range of parameters, which depend on the intensity of the ferromagnetic interaction of spins $S_{i}^{A}$.