On switching field dependence of the thermally excited single domain particles

Analysis of the characteristic dependency of the switching field distribution of a system of noninteracting single domain particles was conducted based on the bi-state, nonequilibrium probabilistic approach. The analysis was carried out as a function of applied field orientations, transition energy barrier variation, and in combination with a given distribution of the particle size and anisotropy constant, under the influence of thermal relaxation. The concept of the blocking temperature that the energy barrier being approximately equal to ~25 k _BT was shown to be invalid unless the period of the field sweep is ~1 h