Thermomagnetics of interacting magnetic particles

Thermomagnetics of a system of interacting particles with log normal distribution of particle size and anisotropy constant was studied self-consistently using a Monte Carlo calculation within the mean-field approximation. Characteristic hysteretic behavior and reversible transverse susceptibility (RTS) were investigated. The salient features are as follows: The hysteresis loops become sheared with increasing anisotropy distribution, σ_K, while their slopes steepen with the mean field strength α. For a homogeneous systems RTS peaks increase sharply with α, both at the anisotropy field H_K and coercive field H_c. For random systems, both peaks become shallower and blunted with increasing σ_K. Mean field strength α causes the peak positions of RTS at H_K to shift to lower values, while the shift at H_c depends subtly upon the interplay among α, σ_K and texture of the system. For random systems the shift is toward higher H _c values with increasing α. For systems with constant α, however, it shifts toward lower values with increasing σ _K