Effect of substitution of divalent ions on the electrical and magnetic properties of Ni-Zn-Me ferrites

The effect of Cu/sup 2+/, Cd/sup 2+/, Co/sup 2+/, Ca/sup 2+/, Mn/sup 2+/, and Mg/sup 2+/ ions on the physical properties of stoichiometric Ni/sub 0.5/Zn/sub 0.5/Fe/sub 2/O/sub 4/ ferrite is investigated. The specimen is prepared by the conventional manufacturing method without atmosphere control. The divalent ions replace one-half the Ni/sup 2+/ ion molar content. We found that the magnetic and electrical properties of Ni-Zn ferrite changes considerably with the substituent species. Copper ions play an important role in lowering the sintering temperature and increasing density. Manganese and cobalt ions increase electrical resistivity by about two orders of magnitude, while the Ca and Mn ions improve thermal stability of the initial permeability. We also discuss our investigation of the physical properties of the Ni-Zn-Me ferrites on the basis of site occupation of the cation species in the spinel structure.