Preparation and Structural Characterization of CaCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> Doped with Nickel, Ferrite, Manganese and Cobalt

Abstract

Transition metal oxide-doped CCTO (CaCu3Ti4O12) ceramics were prepared by a conventional solgel synthesis method and the effects of pure CCTO and CCTO doped with Mn, Fe, Co, Ni to the crystal structure, microstructures and dielectrical properties of samples were investigated. The phase composition and microstructure were studied by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis reveals that all samples exhibited multiphases with the pseudo-perovskite cubic CCTO phase with space group Im-3 as the main phase in undoped and doped CCTO samples. Peaks of monoclinic CuO and peroveskite CaTiO3 could also be seen in all samples which indicate that solid solution of CuO in CaTiO3 lattice was incomplete.SEM results show that doping effectively enhanced densification. SEM micrographs also suggested that the morphologies of doped CCTO ceramics had showed a matrix consisting of large grains wherein the small grains were embedded between the larger grains. Dielectric properties of pure and doped CCTO were investigated in a broad frequency range of the dielectric constant reached a value as high as εr = 29.4 at room temperature for CCTO doped with Ni at frequency (1000 Hz). Besides the sintering conditions, the microstructure and the dielectric properties of the CCTO are strongly influenced by type of doping elements.