Monte Carlo studies of critical phenomena in mixed spin-3/2 and spin-5/2 Ising model on square lattice

Abstract

We used a Monte Carlo simulation to analize the magnetic behavior of Ising model of mixed spins $S_{i}^{A}$= $\pm 3/2, \pm 1/2$ and \linebreak $\sigma_{j}^{B}$ = $\pm 5/2, \pm 3/2, \pm 1/2$, on a square lattice. Were studied the possible critical phenomena that may emerge in the region around the multiphase point $(D/|J_{1}|=-3, J_{2}/|J_{1}|=1)$ and the dependence of the phase diagrams with the intensities of the anisotropy field of single ion ($D/|J_{1}|$) and the ferromagnetic coupling of exchange spin $S_{i}^{A}$ ($J_{2}/|J_{1}|$). The system displays first order phase transitions in a certain range of the parameters of the Hamiltonian, which depend on $D/|J_{1}|$ and $|J_{2}/|J_{1}|$. In the plane ($D/|J_{1}|, k_{B}T/|J_{1}|$), the decrease of $|D/|J_{1}||$, implies that the critical temperature, $T_{c}$, increases and the first order transition temperature, $T_{t}$, decreases. In the plane ($J_{2}/|J_{1}|, k_{B}T/|J_{1}|$), $T_{c}$ increases with the increasing of $J_{2}/|J_{1}|$, while that $T_{t}$ decreases.