Hysteresis jumps in magnetic systems with random anisotropy

Monte Carlo simulations on three-dimensional lattices have been performed considering a simple model of a ferromagnetic spin system in an external magnetic field and with a random local anisotropy. For some particular values of the ratio between the anisotropy strength and the exchange constant, we obtain hysteresis cycles exhibiting sharp jumps that disappear when increasing temperature, in agreement with experimental results for some cerium compounds.