An experimental investigation of magnetization reversal in advanced metal particles

The basic processes of magnetization in metal particles for advanced recording technology, with high coercivity and saturation magnetization, are experimentally investigated. The study is carried out through the experimental analysis of the rotational hysteresis, the measurement of angular dependence of the coercive field, the evaluation of the magnetic anisotropy and of its distribution and the determination of the thermal activation volume, as deduced from the variation of the magnetization with time, in correlation with the results of the particle structure analysis. The analysis indicates that the magnetization reversal of the whole particle is incoherent, or not cooperative, but that coherent rotation can take plate in the crystallites composing the particle itself.