INVESTIGATION OF STRUCTURAL, DIELECTRIC AND LECTRICAL PROPERTIES OF COPPER AND MAGNESIUM SUBSTITUTED ZINC FERRITE MATERIAL

Abstract

Magnetic spinel ferrites are important materials owing to their outstanding electrical and magnetic properties. Their distinctive qualities such as high electrical resistivity, high permeability and negligible eddy current losses for high-frequency electromagnetic wave propagation make them suitable for many technological applications. In this study, ZnFe2O4 and Zn0.9Cu0.05Mg0.05Fe2O4 nanoferrite materials were synthesized by sol-gel combustion method. The effect of Cu2+and Mg2+ for Zn2+ substitution on thermal structural, optical, electrical and dielectric properties of ZnFe2O4 were investigated using thermogravimetric analysis (TGA), differential thermal analysis (DTA), x-ray powder diffraction (XRD),Ultra violet visible (UV-Vis) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy and Impedance spectroscopy (IS). From TGA/DTA analysis, compound formation, temperatures as well as the weight loss regions were identified. The XRD results confirmed that all XRD peaks appeared from both ferrites were very sharp and well-defined, which indicates a high crystallinity of both compounds. The average crystal sizes were found to be 48.31nm and 48.65 nm for ZnFe2O4 and Zn0.9Cu0.05Mg0.05Fe2O4, respectively. This confirmed that the substitution of Cu and Mg cations into ZnFe2O4 causes an increase in crystal size. In FT-IR study, two strong absorption bands between metal-oxygen ions were identified in both compounds. These absorption bands revealed the formation of the cubic spinel structure, which is in agreement with XRD results of the compounds. The optical band gap values were found to be 2.78ev and 2.7eV for ZnFe2O4 and Zn0.9Cu0.05Mg0.05Fe2O4ferrites, respectively. At room temperature, the complex-plane impedance analysis and the effect of frequency on the impedance and dielectric properties were also investigated in this study. The real and imaginary impendence for both compounds were found to decrease with increase in frequency. It was also found that the dielectric constant decreases continuously with increasing frequency and becomes constant at higher frequency regions, which indicates that the major contribution to the polarization comes from orientation polarization.