Why do soft ferrites have high electrical resistivity?

Soft ferrites achieve high electrical resistivity through their manufacturing process, which involves oxidizing the grain boundaries of the material. This oxidation creates resistive internal layers within the ceramic structure.1

By increasing electrical resistivity, soft ferrites effectively reduce the occurrence of eddy currents. These currents are typically induced by rapidly fluctuating magnetic fields and can lead to significant energy loss in the form of heat. Because of this property, soft ferrites are highly valued for use in transformers and telecommunications equipment, particularly in applications operating at higher frequencies where eddy current losses would otherwise be problematic.312