Dielectric Properties of Intergrowth Ferroelectrics in the System Bi2.5Nam-1.5NbmO3m+3 (m= 2, 3 & 4)

Abstract

The Aurivillius phases are bismuth layer structure ferroelectric compounds [BLSF]. These compounds received increase interest due to their properties which are suitable for varieties of technical devices like ferroelectric memories, high temperature piezoelectric, catalyst application etc. In this thesis, BLSF compound in the system Bi2.5Nam-1.5NbmO3m+3(m= 2, 3 & 4) were successfully synthesised through solid oxide reaction route, through analysing their decomposition behaviour using DSC-TG instrument. Pure phases of individual compound and their intergrowths were formed after calcination at 800oC. The powders were sintered to more than 90% of their theoretical density. The powder and sintered ceramics were characterize for their phase formation by XRD analysis, lattice parameter determination, bulk density of sintered product by Archimedes principle, microstructural analysis using scanning electron microscope. For dielectric and ferroelectric properties measurement, silver electrodes were applied in the specimen and the properties were measure using LCR meter in the frequency range 1 kHz -1 MHz The ferroelectric polarisation behaviour with applied electric field of these compounds was evaluated using ferroelectric loop tracer. The intergrowth compounds show higher dielectric and ferroelectric properties compare to their individual compounds. So the intergrowth compounds may be suitable for high frequency dielectric application.