Ferrites with constricted loops and thermal magnetic treatment

After comparing the different types of magnetic hysteresis loop of metallic ferromagnets and non-metallic ferrites, the existence of constricted loops in ferrites containing cobalt oxide is pointed out. The necessary prerequisites in achieving loops of this type are presented, and their field and temperature dependence are demonstrated. In full analogy with metallic ferromagnets of the Perminvar type, these ferrites are susceptible to heat treatment in a magnetic field. The influence of the field strength as well as the temperature dependence of the treating process is shown.