Magnetic behavior of a mixed Ising ferrimagnetic model in an oscillating magnetic field

The magnetic behavior of a mixed Ising ferrimagnetic system on a square lat tice, in which the two interpenetrating square sublattices have spins sigma (+/- 1/2) and spins S (+/- 1,0). in the presence of an oscillating magneti c field. has been studied with Monte Carlo techniques. The model includes n earest- and next-nearest-neighbor interactions, a crystal field, and the os cillating external field. By studying the hysteretic response of this model to an oscillating field, we found that it qualitatively reproduces the inc reasing of the coercive field at the compensation temperature observed in r eal ferrimagnets, a crucial feature for magnets-optical applications. This behavior is basically independent of the frequency of the held and the size of the system. The magnetic response of the system is related to a dynamic al transition from a paramagnetic to a ferromagnetic phase and to the diffe rent temperature dependence of the relaxation times of both sublattices.