Study of the dielectric, optical and microstructure properties of CaCu3Ti4O12-PbZr0.48Ti0.52O3 ceramic system with different compositions

Abstract

In this paper, composite ceramics (1-x)CaCu3Ti4O12–(x)PbZr0.48Ti0.52O3 (with x =0.00, 0.50 and 1.00), denoted CCTO-PZT, were prepared by a three-stages modified method, in order to achieve high dielectric constant and low loss. Structural investigations carried out by X-ray diffraction (XRD), and FT-IR spectroscopy showed the formation of pure cubic and tetragonal phases for x = 0.00 and x=1.00 compositions, respectively. XRD showed the coexistence of both phases in the CCTO-PZT composite. The morphology of the ceramics was examined by scanning electron micrograph (SEM), results reveal a homogeneous microstructure with two types of grains corresponding to PZT (smaller grains) and CCTO (large grains). Dielectric measurements carried out by an impedance analyzer; show that the dielectric constant of the CCTO-PZT composite is higher than the pure samples (CCTO and PZT) one. The temperature dependence of the ac conductivity indicated that the conduction follows the Arrhenius law and the conduction process is due to the single and the doubly ionized. The optical band gap of the PZT is 2.25 eV, and the band gap decreased in the CCTO/PZT composite.