Study of dielectric, AC-impedance, modulus properties of 0.5Bi0.5Na0.5TiO3 • 0.5CaCu3Ti4O12 nano-composite synthesized by a modified solid state method

In the present research paper 0.5Bi(0.5)Na(0.5)TiO(3) center dot 0.5CaCu(3)Ti(4)O(12) nano-composite has been successfully synthesized by a simple, fast, and modified solid state method and shows improvement in both the dielectric constant (epsilon(r) similar to 7007) and dielectric loss (tan delta similar to 0.2) at 1 kHz, at room temperature. X-ray diffraction analysis showed the existence of Bi0.5Na0.5TiO3 as a minor phase alongside the major phase of CaCu3Ti4O12. Average crystallite size calculated by XRD and particle size observed by transmission electron microscopy analysis were in good agreement. Energy dispersive X-ray analyses showed the presence of Ca, Cu, Bi, Na, Ti, O and demonstrated the purity and stoichiometry of the composite. The low frequency performance of the composite was estimated by measuring the frequency dispersion of the dielectric constant, dielectric loss, and AC electrical conductivity. The AC conductivity spectrum obeyed the Jonscher power law. Complex impedance spectroscopic studies reveal that the electrical relaxation process was temperature dependent and non-Debye type. The temperature dependence of the relaxation time was found to obey the Arrhenius law. The activation energy value (E-a similar to 0.84 eV) and relaxation nature of the modulus spectroscopic curve has been governed by the thermal motion and hopping mechanism of oxygen ion vacancies for electrical transport processes. (C) 2014 Elsevier Ltd. All rights reserved.