Structural and electrical properties of lithium cobalt nanoferrites prepared by sol–gel method

Lithium cobalt nanoferrites having the compositional formula Li 0.5-x/2 Co x Fe 2.5-x/2 O 4 with x varying from 0.00 to 0.12 in steps of 0.03 were prepared by the chemical sol–gel method. Samples were heated at two different temperatures namely 300°C and 500°C for 4 h. Structural characterization of the samples was done using X-ray diffraction (XRD) technique and confirmed the formation of single phase with spinel structure in all the samples. From the XRD data, the lattice parameter was calculated and found to range from 82.87–83.35 nm while the crystallite size was found to be in the range 17–34 nm. Microstructural studies were carried out using the Scanning Electron Microscopy and revealed the microstructures with grain size ranging from 35–70 nm. Electrical properties like dielectric constant, dielectric loss and AC conductivity for these nanoferrites were investigated. The frequency variation of room temperature dielectric constant, dielectric loss and AC conductivity were studied in the frequency range 100 Hz–1 MHz, and a dispersive behavior was observed, which has been attributed to the Maxwell–Wagner type of interfacial polarization.