Complex susceptibility of high-resistivity ferrites

A new method of presentation of the variation with frequency of the complex susceptibility of ferrites brings out clearly its behaviour at high frequencies. This method is applied to results of measurements made at very close frequency intervals on Mg¿Al and Ni¿Zn ferrites. The susceptibility of some of these ferrites presents several anomalies which appear on the curves as sinuosities or loops. The possible causes of these anomalies are discussed with the help of a comparison of results obtained on the same samples with and without superimposed d.c. magnetic fields. The influence of Al2O3 content on permeability and losses of Mg¿Al ferrites is also examined.