Synthesis of Bi4.5Na0.5Ti4O15 by co-precipitation route and optimization of calcination and sintering temperatures

Present work reports the synthesis of four-layered Aurivillius compound Bi4.5Na0.5Ti4O15 by co-precipitation route at different calcination (500 degrees C, 600 degrees C and 700 degrees C) and sintering temperatures (900 degrees C and 1000 degrees C). The role of calcination temperature on phase formation and the influence of sintering temperature on ferroelectric and dielectric properties are investigated. The X-ray diffraction analysis reveals that 700 degrees C is the optimal calcination temperature at which pure phase Bi4.5Na0.5Ti4O15 is obtained. Ferroelectric and dielectric properties improve with an increase in sintering temperature due to the formation of higher density grains. The ceramic sintered at 1000 degrees C is found to show higher value of remanent polarization (2P(r)=0.38 mu C/cm(2)), dielectric constant (23.5 at 1 kHz) and low dielectric loss. However, leakage current is observed in these ceramics due to creation of bismuth vacancies at higher temperature.