COMPARISON OF THE EFFECTS OF TIO2-GEO2 AND R2O3 SUBSTITUTIONS IN A HIGH-FREQUENCY NICKEL ZINC FERRITE

The present work describes the effects of two types of substitutions T iO2-GeO2 and R2O3 on the magnetic and transport properties of a high f requency nickel-zinc ferrite prepared by a conventional ceramic proced ure. By substituting the iron in Ni0.7Zn0.3Fe2O4 with Ti or/and Ge the one hand, and with rare earth ions (R = Yb, Er, Dy, Tb, Gd, Sm, Ce) o n the other hand, a set of twelve compounds was obtained. We found tha t the saturation magnetization permeability. Curie temperature, resist ivity, porosity, and thermal stability are all affected by the substit ution. The best results from the point of view of magnetic and electri cal characteristics acceptable for high frequency were obtained for th e mixed Ge-Ti substitution with equimolar quantities of Ge and Ti and for Gd ion with the stable valence of 3+. For these substitutions, a g ood compromise between the properties was obtained.