Electrical properties of copper and titanium-codoped zinc ferrites

In this study, the effects of Cu and Ti substitution on the sintering behavior, substitution mechanism, resistivity and dielectric properties of (Zn)(Cu_x Ti_x Fe_1.98-2x)O_3.97 were investigated using X-ray diffractometer, scanning electron microscopy, and dilatometer. The results indicate that codoped Cu²⁺ and Ti⁴⁺ can effectively promote zinc ferrite densification. For the samples with x = 0-0.05, Cu²⁺ and Ti⁴⁺ ions dissolved into the spinel structure and mainly occupied the octahedral sites, which resulted in an increase in resistivity. For the specimen with x = 0.1 and 0.2, the Cu-rich and Zn-rich precipitates occurred at the grain boundary, leading to a decrease in resistivity. The variations in dielectric constant for samples with various x values as a function of frequency can be explained using the space charge polarization arising from the differences between the conductivity of the various phases present.