Cation distribution and curie temperature in some ferrites containing copper and manganese

For some ferrites, containing copper and manganese an investigation was made of the influence of the modification of the cation distribution on the Curie point and the anomaly of the temperature variation of the resistivity in this point. The cation distribution was modified by oxygen treatment and was proved by saturation magnetization measurements. It is established that after oxygen treatment the Curie point, for all samples, is shifted to higher temperatures due to the oxidation of Cu1+ ions which migrate from tetrahedral to octahedral sites. For the ferrites which contain also manganese ions, the Curie point shift after oxygen treatment is less pronounced because of migration of manganese ions from octahedral to tetrahedral sites, which results in a shift of the Curie points to lower temperatures.