Improvement in dielectric and ferroelectric property of dysprosium doped barium bismuth titanate ceramic

The dysprosium doped barium bismuth titanate ceramic with general formula BaBi_4−xDy_xTi₄O₁₅ (BBDT) were prepared by solid-state reaction process. The effect Dy³⁺ on Bi³⁺ sites on the structural, microstructure, dielectric, conductivity and ferroelectric behaviour of BaBi₄Ti₄O₁₅ ceramics were investigated. X-ray diffraction and Raman analysis confirmed the above compositions to be monophasic with orthorhombic structure and belonged to the m = 4 member of the Aurivillius family of oxides. The SEM micrographs show well define grains in all ceramics. From the dielectric behavior as a function of temperature it was observed that the maximum dielectric constant decreases and transition temperature increases with an increase in Dy content. The diffuse nature of the dielectric behavior of BBDT ceramics obtained from the modified Curie–Weiss law and it was attributed to the A site cationic disorder. The frequency dependence AC conductivity obeys the power law and the DC conductivity shows a thermally activated process. Ativation energies were obtained from the Arrhenius law and it is observed that oxygen vacancy (\({\text{V}}_{\text{O}}^{ \cdot \cdot }\)) are mainly responsible for the conduction mechanism in the systems. The ferroelectric properties were studied by P–E hysteresis loop and it observed that the remnant polarization increases with Dy doping.