ON THE RELAXATION OF SIMPLE MAGNETIC SYSTEMS

The relaxation at constant applied field and temperature of a simple magnetic system is evaluated in the framework of the micromagnetic approximation and using a Monte Carlo algorithm. Our results, and particularly, those corresponding to the time evolution of the probability of magnetic moment reversal, evidence remarkable differences with the classical Arrehnius–Neel predictions. These differences are linked to the fact that relaxation proceeds through the formation of structures involving a large number of degrees of freedom.