  We propose a nonequilibrium Monte Carlo (MC) approach to explore
nonequilibrium dynamical ferromagnetism of interacting single molecule magnets
(SMMs). Both quantum spin tunneling and thermally activated spin reversal are
successfully implemented in the same MC simulation framework. Applied to a
typical example, this simulation method satisfactorily reproduces experimental
magnetization curves with experimental parameters. Our results show that both
quantum and classical effects are essential to determine the hysteresis
behaviors. This method is effective and reliable to gain deep insights into
SMMs.
