Theoretical studies of the field-cooled and zero-field cooled magnetization of interacting fine particles

We have applied a Monte-Carlo model of the properties of an interacting fin e particle system to calculations of the field-cooled (FC) and zero-field c ooled (ZFC) magnetization. The variation of T-g, the temperature peak, in t he ZFC is also calculated. For an interacting system the effective energy b arrier distribution is dependent on the packing density, and this is reflec ted in the T-g vs H curve. An important result is the demonstration that ma gnetostatic interactions between the particles can give rise to a peak in t he FC magnetization. This is in agreement with experiments and is a result of the magnetic order introduced by the magnetostatic interactions. [S0021- 8979(99)51308-X].