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)CaCu 3 Ti 4 O 12 -(x)PbZr 0.48 Ti 0.52 O 3 (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.

Thermal behavior of Ni-doped CaCu3Ti4O12 ceramics

“…The main components of CCТО and Ni-doped CCTO IR spectra are reproduced with the data given in the literature. On spectra of all samples three absorption bands in the area of fingerprints at ≈410, 488 -490, 540 cm −1 , connected according to data [27,28] with valence oscillations TiOTi (410), Сu-O (≈489) and Ca-O bonds at 540 cm −1 in CCTO are clearly fixed. The authors of [29,30] connect the absorption bands at 540 and 489 cm −1 with the valence oscillations of TiO bond in the octahedron TiO 6 .…”

Spectroscopic study of Co-doped CaCu3Ti4O12

“…Three absorption bands in the fingerprint region at ≈408, 488, 539 cm −1 are clearly recorded on the spectra of CCTO samples, associated according to the data [33] with valence oscillations of TiOTi (410), Cu-O (≈489) and Ca-O bonds at 540 cm −1 in CCTO. The authors [34,35] connect the absorption bands at 540 and 489 cm −1 with the valence oscillations of TiO bond in the octahedron TiO 6 . The wide diffuse absorption band in the region of 600 -1200 cm −1 , typical for CCTO and Ni, Co-doped CCTO, observed earlier in works [36,37], attracts attention.…”