Electrical properties of ZnO:ZnAlO nanoparticle matrix composites

Abstract In this communication, we report the results of the investigations on the structural and electrical properties of ZnO:Zn 0.95 Al 0.05 O (ZnO:ZAO) nanoparticles matrix composites, prepared with ZnO nanoparticles as fillers and ZAO as a matrix using sol–gel and solid state reaction method, respectively. In order to study the structural properties, θ–2θ X–ray diffraction (XRD) measurement was performed at room temperature using CuK α radiation. The crystallite size was calculated using Scherer's formula. Frequency dependent dielectric, ac conductivity and impedance have been carried out using high precision LCR meter in the frequency range of 20 Hz to 2 MHz. Dielectric constant was also recorded for higher frequency range up to 3 GHz for all the samples and comparison based discussion has been represented for the possible relaxation processes at lower and higher frequency ranges. Relaxation mechanism and universal dielectric relaxation (UDR) model have been fitted to dielectric behavior of the samples understudy throughout the frequency range (both, lower and higher). Frequency dependent variation in ac conductivity has been discussed on the basis of correlated barrier hopping (CBH) mechanism for presently studied samples. Role of ZnO fillers content in the composites has also been discussed for the observed variations in impedance with frequency. Also, temperature (25–200 °C) dependent dielectric, conductivity and impedance were studied for all the samples understudy. Variations in estimated activation energy (E a ) with ZnO fillers content and frequency have been discussed in detail.