Investigation of Dielectric, Ferroelectric and Conduction Behavior of Dy³⁺ Substituted SrBi₂Ta₂O₉ Bismuth Layer Structured Ceramics

Abstract

The present manuscript explores the impact of Dy doping in the Tantalum-based bismuth layer structured ferroelectrics with chemical composition of Sr(Bi1-xDyx)2Ta2O9 (where x= 0.00, 0.025, 0.05, 0.075 and 0.10) prepared by mixed oxide process. X-ray diffraction study of all the ceramics implement orthorhombic phase without any secondary phase. The polycrystalline nature and grain distribution in the materials is studied from scanning electron microscope study. The temperature dependent dielectric performance of Dy doped SBT ceramics at selected frequencies indicates diffuse order phase transitions with reduction in transition temperature (Tc) and relative permittivity with doping level. The residual polarization and coercive field reduce with doping. The conduction mechanism was analyzed using the frequency and temperature domain impedance spectroscopy for all composition. The electrical contribution from both grains and grain boundary in the doped ceramics in the reported temperatures is confirmed from the Nyquist plots and the non-Debye type of relaxation mechanism is manifested from the depressed semicircles in all of them. The ac conductivities variation with frequencies at the studied temperatures follow Jonscher’s power law and the fitting parameters suggests that the conduction mechanism obey the correlated barrier-hopping model.