Dielectric Properties of CaCu<sub>3</sub>Ti<sub>4</sub>O<sub>12</sub> Synthesized by Different Routes

Abstract

The perovskite CaCu3Ti4O12, with giant electric permittivity, was prepared by a soft chemistry route and by the solid state synthesis technique. The main purpose of this work is to verify the effects of the synthesis techniques on the powder characteristics, and the microstructure and dielectric properties of the sintered materials. The synthesized nanopowders were calcined, pressed into pellets and sintered using the same procedures as for the materials prepared by the conventional method. Phase analysis was performed by X-ray diffraction, microstructure observations were carried out by scanning electron microscopy, and the dielectric properties were studied by impedance spectroscopy. The electric permittivity ranged from 11,600 to 27,000 and from 5,000 to 9,000 for specimens prepared by the conventional and the soft chemistry techniques, respectively, and the dielectric losses varied between 0.1 and 1.3 (conventional) and 0.095 and 0.3 (soft chemistry) depending on the sintering temperature.