Structural and dielectric properties of substituted barium titanate ceramics for capacitor applications

Abstract Iron doped barium calcium titanate (BCT) ceramics with compositions Ba 0.90 Ca 0.10 Ti 1−3 x /4 Fe x O 3 were prepared by a solid state reaction method. Pure perovskite tetragonal structure was confirmed by X-ray diffraction (XRD) analysis which is in coherence with the results obtained by Rietveld refinement. Relative density has been found above 90 percent. Tetragonality has been observed to decrease with Fe 3+ ion substitution for Ti 4+ .The dielectric properties of all the ceramic samples investigated as a function of temperature and frequency reveal that the transition temperature ( T c ) decreases on doping of iron content from 396 K to 349 K and an appreciable decrease in dielectric loss is observed on addition of Fe 3+ ions to BCT ceramics. The fitting of experimental data of dielectric constant ( e ′) with Curie Weiss Law and Power Law confirms the presence of first order transitions and diffusive behavior of the studied compositions. With increase in Iron content, the room temperature e ′ is observed to increase from 1450 to 2199 whereas, room temperature tan  δ decreases from 0.024 to 0.009.The temperature coefficient ( T cc ) has also been calculated for all the samples. These studies suggest the application of prepared ceramic compositions for capacitor applications at room temperature and actuators.