Dielectric and Ferroelectric Behavior of Bismuth-Doped Barium Titanate Ceramic Prepared by Microwave Sintering

Bismuth-doped barium titanate ceramics with the general formula Ba1−x Bi2x/3TiO3 (x = 0.0, 0.01, 0.025, 0.05) have been prepared by the solid state reaction technique. The phase formation and structural property of all compositions have been studied by x-ray diffraction (XRD) pattern and Rietveld refinement. XRD pattern reports the single phase tetragonal crystal system with space group of P4mm. All compositions have been sintered at 1100°C in a microwave furnace for 30 min. The variation of dielectric constant with respect to temperature and frequency was studied and it was found that the dielectric constant decreases whereas transition temperature increased with the increase in Bi content. The diffusivity parameter was calculated by the modified Curie–Weiss law and the diffusivity increased with the increase in Bi content. The ferroelectric property was studied by the P–E hysteresis loop and it was observed that the saturation polarization decreased, but the coercive field increased with Bi content. The optical band gap was calculated from UV–Visible spectroscopy and found to decrease with Bi content.