Microstructure and electrical properties of Bi2O3 excess Bi3.25La0.75Ti3O12 ferroelectric ceramics

Bi3.25La0.75Ti3O12 (BLT) ceramic samples derived from different amount of initial Bi2O3 excess were prepared by conventional solid-state method. The microstructures and electrical properties of BLT ceramic samples are strongly dependent on the initial Bi2O3 excess content, as examined by XRD, SEM, Raman spectra, P-E hysteresis loops and dielectric, etc. Appropriate initial Bi2O3 excess reduces the leakage current and loss tangent and therefore improves polarization of BLT ceramics, while too much initial Bi2O3 excess leads to a reduction in polarization and an increase in coercive field. The best polarization behavior was observed for the BLT ceramic sample derived from 8 mol% initial Bi2O3 excess, where a remnant polarization (2Pr) of 20.4 μC cm−2 and coercive field (Ec) of 38 KV cm−1 were shown. A similar change in dielectric constant with the increase of initial Bi2O3 excess content was also observed and the highest dielectric constant of 142.9 was obtained for the BLT ceramic derived from 8 mol% initial Bi2O3 excess.