Structural, optical and dielectric studies of NixZn1-xFe2O4 prepared by auto combustion route

NixZn1-xFe2O4 (0 <= x <= 1) powders were synthesised by the auto combustion method. The derived samples show well defined peaks of cubic spinal structure with space group Fd3m. The lattice parameter calculated increased from 0.8372 nm to 0.8429 nm with raise of Zn content. The average crystallite sizes were determined by using Debye-Scherer method and found to be in the range of 18-23 nm. Microstructural analyses show the regular and uniform grain morphology. Raman analyses demonstrated that the peaks have symmetric and asymmetric stretching as well as symmetric bending. Fourier transform infrared spectroscopy was used to investigate the structure and shows the changes in the tetrahedral and octahedral bond stretching. Photoluminescence measurements indicated intense emission in the wavelength range lie in blue-green region. The composition with x=0.2 showed highest intensity and explained on the basis of disordered cluster model. Dielectric analyses showed frequency sensitive behaviour in the low frequency region and frequency independent characteristics at high frequency side. The composition with x=0.2 showed highest dielectric constant and lowest dielectric loss in the studied frequency range. The ac conductivity showed a power law behaviour and conduction is explained on the basis of hoping mechanism. (c) 2011 Elsevier B.V. All rights reserved.