Large-scale computer investigations of finite-temperature nucleation and growth phenomena in magnetization reversal and hysteresis (invited)

An overview of some of the results obtained from long-time dynamic simulations of models of magnetic nanoparticles and thin magnetic films is presented. The simulation methods include dynamic Monte Carlo simulations and micromagnetic simulations. The effects of nucleation and growth due to the finite temperature display similar behaviors for various models of magnetic materials and computational approaches. These behaviors can only be seen computationally with the use of advanced algorithms and massively parallel computers. Several different modes of reversal are seen at finite temperature, and crossovers from one mode of reversal to another for the same system can be seen as the temperature or applied field is changed. Statistical interpretations of both field-reversal experiments and hysteresis experiments are shown to be necessary to understand the finite-temperature behavior of magnetic nanoparticles and thin magnetic films. (C) 2002 American Institute of Physics.