Study of the properties of SBT ceramics doped with different concentrations of Ca

Abstract This study investigated how Ca doping affects the electrical properties of Sr 2 Bi 4 Ti 5 O 18 (SBT) ceramics. Among the samples tested, a sample with a substitution level of 0.15 showed the highest a -axis orientation and the largest lattice distortion. Through XPS analysis, it was found that the formation of oxygen vacancies is suppressed by Ca substitution in SBT. A large remnant polarization (2 Pr ) of 17.7 μC/cm 2 and small coercive field (2 Ec ) of 91 kV/cm was observed for the Ca 0.15 Sr 1.85 Bi 4 Ti 5 O 18 (CSBT-0.15) ceramic, which indicated that this sample possessed the best ferroelectric properties. As the substitution level increased, the variation of the leakage current density first decreased and then increased, and the sample with the substitution level of 0.15 showed the smallest leakage current density of J = 1.1 × 10 −6 A/cm 2 at ~80 kV/cm. For the investigated Ca x Sr 2-x Bi 4 Ti 5 O 18 (CSBT) ceramic samples, space-charge-limited conduction (SCLC) was determined to be the main conduction mechanism.