Exceptional physical properties of Ca, La and Nb co-substituted Sr2Bi4Ti5O18 ceramics
摘要
The solid-state method was employed to prepare the Sr2−xCaxBi4−xLaxTi5−xNbxO18 (SCBLTN-x) ceramic, and studied their changes occurred on structural and physical properties. The substitution and co- substitution ion concentration 10 mol% was observed through X-ray diffraction (XRD) analysis, after that it forming impurity phase. A plate-like shape morphology along with decreasing average grain with an increasing of substitution and co- substitution ion concentration was noticed via scanning electron microscope (SEM) analysis. A 5 mol% doping and co-doping ions on Sr2Bi4Ti5O18 (SBT5) ceramics showed a superior polarization 2Pr (11.35 µC/cm2) value along with lower leakage current density when compared to other concentration ion substitution on Sr2Bi4Ti5O18 ceramics. Room temperature measured at 1 MHz of the relative permittivity (εr) and dielectric loss tangent (tan δ) were 238 and 0.0116 correspondingly for 5 mol% substituted SBT5 ceramics, which are higher than other compositions in this study. The substitution and co-substitution ions are essential in reducing the electrostatic free energy barrier and reducing the leakage current of SBT5 ceramics, as evidenced by the reported improvement in electrical properties of 5 mol% substitution and co-substitution of SBT5 ceramics when matched with un-substitution SBT5. The improved dielectric properties and ferroelectric properties of substituted and co-substituted SBT5 ceramic could potential candidates for ferroelectric logic and memory devices like FeFETs and FeRAMs application.