Structural and electrical properties of Bi/Na-modified BaTiO3

Studies of preliminary structural and detailed frequency-temperature dependence of electrical (dielectric, impedance, polarization, and conductivity) properties of Bi/Na-modified barium titanate compound have been performed in this work. The proposed compound has been synthesized by a conventional solid-state sintering route with a composition of (Ba0.8Bi0.1Na0.1)TiO3. The prepared sample has been pre-heated (calcined) at 1050 degrees C. Preliminary structural analysis using X-ray diffraction method of the calcined powder confirms the phase purity of the prepared barium titanate compound with tetragonal symmetry. The pellet of this compound has been sintered at 1100 degrees C. Study of the surface morphology of the pellet by scanning electron microscope (SEM) reveals the homogeneous distribution of grains throughout the sample surface. The dielectric study in the temperature range of 25-500 degrees C at different frequencies (1 kHz to 1 MHz) shows a high dielectric constant and low tangent loss in a wide temperature range. The temperature response of AC conductivity with impedance spectrum confirms the semiconducting nature of the material at high temperatures. The Nyquist plots reflect the grain and grain boundary contributions to the conduction mechanism of this modified BaTiO3 compound. The existence of ferroelectricity at room temperature of the above sample is confirmed by polarization versus electric field (P-E hysteresis loop) measurements. The J versus E characteristic suggests the Ohmic conduction mechanism of the Bi/Na-modified barium titanate compound. All the studied properties conclude that this composition has potential for device application in the electronic industry.