Diffuse phase transition and dielectric study in Ba0.95Ca0.05TiO3 ceramic

Temperature and frequency dependent dielectric permittivity of Ba0.95Ca0.05TiO3 ceramic has been studied in the temperature range of 40-250 degrees C at the frequencies, 1, 10, 100 kHz and 1 MHz. Diffuse phase transition and frequency dispersion are observed in the permittivity vs. temperature plots. This has been attributed to the occurrence of relaxor ferroelectric behavior. The observed relaxor behavior has been quantitatively characterized based on the phenomenological parameters. The value of the dielectric constant at higher frequencies markedly dropped. Such a marked drop in the value of the dielectric constant at higher frequencies can be explained in terms of interfacial polarization. The buildup of charges at the grain-grain boundary interface is responsible for large polarization, therefore, the high dielectric constant at lower frequencies. (C) 2010 Elsevier B.V. All rights reserved.