Modeling the effect of interactions in granular magnetic films

The effect of interactions on the blocking temperature of granular magnetic films is modeled using a variable time step Monte Carlo method. Both magne tostatic and exchange interactions are considered in the calculation of fie ld cooled magnetization curves. Cubic grains with 28 Angstrom side lengths are randomly packed within a larger cubic volume. Each grain has a random c rystalline easy axis. For the parameters simulated, magnetostatic interacti ons do not have an effect on the blocking temperature, and exchange interac tions cause average blocking temperatures to increase. (C) 2001 American In stitute of Physics.