Enhanced in-plane ferroelectric polarizations with low in-plane leakage currents in Ca-doped SrBi₂Ta₂O₉ textured ceramics

The Aurivillius-phase layered material SrBi₂Ta₂O₉ possesses an extremely low leakage current (~10⁻⁹ A·cm⁻²) along the out-of-plane direction with in-plane ferroelectricity, which brings difficulties in achieving high ferroelectric performance and low leakage current simultaneously in randomly oriented ceramics. Here, highly textured SrBi₂Ta₂O₉ ceramics with a texture degree of f = 0.985 are prepared using templated grain growth (TGG) technology with a tape-casting method. The in-plane remnant polarization achieves 15.83 μC·cm⁻², which is increased by 197% compared with that of the SrBi₂Ta₂O₉ randomly oriented ceramic. Doping Ca is found to reduce the in-plane leakage current density to J = 5.924×10⁻⁷ A·cm⁻², which is attributed to the increased electronic band gap. This research presents an effective route for developing high-performance SrBi₂Ta₂O₉-based ferroelectric devices.