Resumo

DE LA ESPRIELLA VELEZ, N.; MADERA YANCEZ, J.  e  PAEZ MESA, M. S.. Monte Carlo studies of critical phenomena in mixed spin-3/2 and spin-5/2 Ising model on square lattice. Rev. mex. fis. [online]. 2014, vol.60, n.6, pp.419-424. ISSN 0035-001X.

We used a Monte Carlo simulation to analize the magnetic behavior of Ising model of mixed spins S_i^A= ±3/2, ±1/2 and σ_j^B = ±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^A (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|,k_BT/|J₁|), the decrease of |D/|J₁||, implies that the critical temperature, T_c, increases and the first order transition temperature, T_t, decreases. In the plane (J₂/|J₁|, k_B T/|J₁|), T_c increases with the increasing of J₂/|J₁|, while that T_t decreases.

Palavras-chave : Ising system; single-ion anisotropy; Monte Carlo simulation; critical temperatures; first-order transitions.

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