Cation distribution and Curie temperature in ferrites

The influence of the cation distribution on the tetrahedral and octahedral sites upon the Curie temperature in some ferrites is studied. The modification of the Curie temperature is provoked by the valency change of the metallic ions and their passage from some crystallographic positions to others.The migration of ions between the two crystallographic positions is proved by saturation magnetization measurements.The cation distribution is modified by a different cooling mode or by a later thermal treatment.