Ordering in cobalt-ferrous ferrites
Various cobalt-ferrous ferrites show a constricted hysteresis loop. After magnetic annealing of the samples the loop becomes rectangular. It appears that the magnetic annealing creates in each crystal a uniaxial anisotropy in a direction which is not necessarily the direction of the applied magnetic field but a crystallographic direction nearest to it. It is suggested that directional ordering is the most probable origin of the anisotropy found.