On the magnetic properties of fine-milled barium and strontium ferrite

The temperature dependence of the specific saturation magnetization of barium and strontium ferrite powders after milling in an attrition mill has been investigated at temperatures between -195°C and the Curie temperature of the ferrites. The experimental results show that the specific saturation magnetization decreases with increasing milling time and that a second, presumably soft-magnetic phase occurs during milling which vanishes during annealing of the powders. The influence of lattice defects introduced by the milling process is discussed.