Effect of thermal history on structural, microstructural properties and J - E characteristics of CaCu3Ti4O12 polycrystalline ceramic

We report, the effect of heat treatments slow cooling, rapid thermal cooling (quenching) and microwave-assisted heating, on structural, microstructural and J - E characteristics of CaCu3Ti4O12 polycrystalline ceramic. Rietveld refinement of X-ray data confirms the emergence of the mono-phasic cubic perovskite structure, diffraction line broadening and change in the relative intensity of diffraction peaks while scanning electron microscopy revealed completely different grain morphology. The observed modifications have been discussed in detail. The strong nonlinear J - E characteristics over the wide temperature range (300-823 K) indicated the existence of a Schottky-type electrostatic potential barrier at the grain boundaries. The parameters, nonlinear coefficient, threshold electric field, potential barrier height suggest suitability of the materials for low voltage varistor applications.