Abstract
When the ferrites are cooled slowly from a high temperature, there are changes in the composition and formation of inhomogenious layers with the gain or loss of oxygen from or to the ambient atmosphere. Therefore, the magnetic properties are not merely determined by the proportion of initial ingredients. The permeability versus temperature curves of MnZn ferrites, before and after grinding the surface of specimens, were measured and ferrous ion contents on the internal and the surface layer were chemically analyzed. From these data, the relation between the distribution of ferrous ion content in MnZn ferrites and the oxygen per cent versus temperature during the cooling processes was discussed.
