A study of dielectric relaxation properties of ZnFe_2-xBi_xO₄ nano Ferrites synthesized by sol-gel combustion method

Abstract

A series of bismuth doped zinc nano ferrite particles with the r formula ZnBixFe2-xO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20 & 0.25) were prepared by sol-gel combustion method; and these compositions were sintered at 600°C for 5 hrs. With the effect of bismuth doping, the structural properties of all prepared samples were characterized by X-ray diffraction (XRD). The X-ray diffraction spectra analyses confirm single phase cubic (FCC) spinal structure. The average crystallite size (D) of the samples found to be in the range 17-20 nm. The dielectric properties viz., dielectric constant (ε′), dielectric loss tangent (tan δ) and AC conductivity σAC) were measured at room temperature in the range 20Hz to 2MHz, which confirm the normal ferrite behavior. In the present research work, we are intended to extend dielectric relaxation studies of these samples with the help of Cole-Cole plots. The Cole-Cole plots of the bismuth doped zinc ferrites were drawn as a function of ε′ and ε″ (where, ε″=ε′ tan δ) and hence we have determined the spreading factor (β) for all the samples. It was observed that β decreases with the increase of the concentration of B2O3. It is noticed that the dielectric parameters ε′, tan δ and σAC have exhibited the similar trend. These samples may find suitable applications in electrolytic elements in battery technology.