Structural, Morphological and Electrical Studies of Co1-x Zn x Fe2O4 Ceramics

Abstract

The Zn-modified CoFe2O4 (CZFO) (Co1−x Zn x Fe2O4 (0.0 ≤ x ≤ 0.4)) is synthesised using the sol-gel auto-combustion method. The structural properties of CZFO at room temperature (RT) are studied using the X-ray diffraction technique. Rietveld refinement XRD data ratified the formation of single-phase cubic spinel with Fd-3m space group. The average crystallite size of CZFO ceramics is measured from the XRD data employing the Williamson-Hall method. The lattice constant is increased with an increase in Zn concentration (x). FESEM micrographs confirm the uniform distribution of grains and the presence of small amounts of pores throughout the sample microstructure. The EDX characterization of these samples confirms the phase purity of compounds. The electrical properties are explored as a function of temperature over wide frequencies. The value of the dielectric constant increases with an increasing Zn concentration. Complex impedance and complex modulus spectroscopic techniques reveal the existence of the non-Debye kind of dielectric relaxation behaviour. AC conductivity (σ ac ) increases with increase in frequency, while decreases with increase in Zn concentration. Temperature-dependent σ ac study suggests the presence of NTCR behaviour in Co1−x Zn x Fe2O4 ceramics. The estimated values of activation energy (E a ) increase with the substitution of Zn in cobalt ferrite.