Strong piezoelectric anisotropy in CaBi4Ti4O15 textured ceramics prepared by templated grain growth method

Abstract

AbstractBismuth layer‐structured ferroelectrics (BLSF) show great potential as piezoelectric materials for high‐temperature applications. In this study, c‐axis/[001]‐textured CaBi4Ti4O15 (CBT) ceramic was synthesized through templated grain growth (TGG) method. A high Lotgering factor (f) of 96% was achieved in textured CBT ceramic using 20 wt% CBT homogeneous template. The piezoelectric coefficient d33 has significantly increased from 7.8 pC/N for random ceramic to 24.3 pC/N for textured ceramic (poled perpendicular to the c‐axis/[001] texture direction), representing an impressive 300% enhancement while maintaining an ultra‐high Curie temperature (TC) of 788°C. In addition, a low dielectric loss (tanδ = 0.4%) and relatively high resistivity (ρ = 1.1 × 1012 Ω·cm) were achieved simultaneously at room temperature. The significant enhancement of d33 in textured CBT ceramic origins from its strong piezoelectric anisotropy. The large d33,T⊥ is due to the nature of polarization switching in CBT (the spontaneous polarization PS of CBT is along a‐axis direction, and the switching of PS is restricted within the a–b plane). Furthermore, the variation of d33,T⊥ remained below 10% across the temperature range of 25–700°C, highlighting the excellent thermal stability of the textured CBT ceramics. These findings suggest that textured CBT ceramic is a promising piezoelectric material for high‐temperature sensor applications.