MAGNETIC CLUSTERING PHENOMENA IN A CRYSTALLINE MIXED FERRIC FLUORIDE - FE0.67CR0.33F3

Static magnetization measurements were performed on a mixed ferric cry stalline fluoride: Fe0.67Cr0.33F3. The evolution of the shape of the h ysteresis loops reveals drastic changes as a function of temperature, whereas the coercive field and the magnetization exhibit singularities . These data are interpreted from a :phenomenological model based on t he existence of two uncompensated weak ferromagnetic sublattices rando mly located on a cubic network. By including a spin relaxation process , such a mechanism explains well the presence of magnetic clustering p henomena, in agreement with Mossbauer data.