Cobalt oxide addition effects on the microstructure and electronic properties of CuZn ferrites

The effects of cobalt oxide addition on the microstructure and electrical properties of CuZn ferrites were investigated. CuZn ferrites with compositions of (CuO)_0.2(ZnO)_0.8(Co₃O₄)_x/3 (Fe₂O₃)_0.986-2x; x = 0, 0.02, 0.04, 0.08, 0.1 were synthesized using a solid state reaction. It was observed that the addition of cobalt will change the amounts and distribution of Cu²⁺, Cu⁺, Fe²⁺, and Fe³⁺ in the grain and grain boundary. The segregation of copper ions at the grain boundary was observed as the substitution of cobalt was increased. Moreover, as the x value was increased above 0.04, second phases of CuO and ZnO were found. The different amounts and distribution of Cu²⁺, Cu⁺, Fe²⁺, and Fe³⁺ in the bulk and grain boundary for samples added with different amounts of cobalt changed the conductivity activation energies of the bulk and grain boundary, and hence affected the space polarization and dielectric properties.