Critical and compensation points of a mixed spin-2-spin-5/2 Ising ferrimagnetic system with crystal field and nearest and next-nearest neighbors interactions

摘要

We perform Monte Carlo simulations to analyze the magnetic properties of a mixed Ising model, where spins S that can take 5 values, 0, ± 1, ± 2, alternate on a square lattice with spins σ that can take 6 values, ±5/2, ± 3/2, ± 1/2. The Hamiltonian of the model includes an antiferromagnetic interaction between the S and σ spins, nearest-neighbors on the lattice, a ferromagnetic interaction between the S spins, next-nearest neighbors on the lattice, and a crystal field. We found that the system presents compensation temperatures in a wide range of the parameters. At the compensation temperature the total magnetization is zero but, contrary to what happens at the critical temperature, the system remains ordered. These temperatures have important technological applications, particularly in the field of thermo-magnetical recording. We calculate the finite-temperature phase diagram of the model. We found that the presence of the compensation temperature is strongly dependent on the next-nearest neighbor interaction term between the S spins, while its value can be calibrated by changing the crystal field.