The dynamics of a mixed spin Ising model with a crystal field on the square lattice are investigated by using the damage spreading technique and Metropolis sampling method. The simulation results reveal that the damage (Hamming distance) shows a very similar temperature dependence to that of the magnetization. The Hamming distance decreases with temperature and there is a critical temperature, beyond which the phase space trajectories of two systems with different initial configurations consist with each other. The critical temperature increases when the strength of the crystal field decreases, and the mixed spin Ising model will degenerate to a standard Ising model under a considerable weak crystal field. The critical temperature decreases to zero continuously as the strength of the crystal filed increases. There is not any first order phase transition observed in the above process and thus no tricritical point exists in this system.

damage spreading; mixed spin Ising model; phase transition