Consequence of pH variation on the dielectric properties of Cr-doped lithium ferrite nanoparticles synthesized by the sol-gel method

Abstract

Nanocrystalline Cr-doped lithium ferrites have been synthesized at different pH values through sol-gel process. Dielectric properties of the synthesized samples were studied via impedance measurements in the frequency range of 100 Hz-7 MHz at room temperature. It was found that the dielectric properties strongly depended on the pH value, and the sample synthesized at pH 3.5 exhibited the highest dielectric constant, on the order of ∼107. In contrast, the sample synthesized at pH 11.5 exhibited the lowest dielectric constant. The occurrence of a peak in the dielectric loss spectra was found to be pH dependent, whereas the AC conductivity increased with frequency and was the highest in the sample synthesized at pH 3.5. The impedance spectroscopy and modulus formulism were also employed to investigate the charge transfer and relaxation dynamic properties. Consequently, dielectric properties of the samples were easily tuned by varying the pH during the synthesis process. © 2015 Elsevier Inc. All rights reserved.