Texture development and dielectric properties of SrBi₂ Ta₂O₉ ceramics processed by templated grain growth

SrBi₂Ta₂O₉ (SBT) textured ceramics were produced by templated grain growth (TGG) using anisometric templates grown by self-flux solution method. SBT templates (5 wt.%) with the dimensions ∼40 μm × 40 μm × 8 μm were embedded in a fine-grained matrix of SBT powder containing a 3 wt.% of Bi₂O₃ excess and partially aligned by conventional uniaxial pressing. Textured SBT ceramics characterized by a Lotgering factor f ≈ 0.4 could then be obtained after sintering at 1250 °C for 2 h. The influence of the pressing and sintering conditions on texture development was evaluated using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Significant improvement of the dielectric and ferroelectric properties was observed when measurements are performed perpendicularly to the pressing direction. This improvement was attested to the apparent alignment of the templates, dielectric anisotropy of SBT and texturing effect due to TGG.