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

We used a Monte Carlo simulation to analize the magnetic behavior of Ising model of mixed spins S i = ±3/2,±1/2 and σ j = ±5/2,±3/2,±1/2, on a square lattice. Were studied the possible critical phenomena that may emerge in the region around the multiphase point (D/|J1| = −3, J2/|J1| = 1) and the dependence of the phase diagrams with the intensities of the anisotropy field of single ion (D/|J1|) and the ferromagnetic coupling of exchange spin S i (J2/|J1|). The system displays first order phase transitions in a certain range of the parameters of the Hamiltonian, which depend on D/|J1| and |J2/|J1|. In the plane (D/|J1|, kBT/|J1|), the decrease of |D/|J1||, implies that the critical temperature, Tc, increases and the first order transition temperature, Tt, decreases. In the plane (J2/|J1|, kBT/|J1|), Tc increases with the increasing of J2/|J1|, while that Tt decreases.