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

Bismuth 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 d(33) 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 (T-C) of 788 degrees C. In addition, a low dielectric loss (tan delta = 0.4%) and relatively high resistivity (rho = 1.1 x 10(12) Omega<middle dot>cm) were achieved simultaneously at room temperature. The significant enhancement of d(33) in textured CBT ceramic origins from its strong piezoelectric anisotropy. The large d(33,T perpendicular to) is due to the nature of polarization switching in CBT (the spontaneous polarization P-S of CBT is along a-axis direction, and the switching of P-S is restricted within the a-b plane). Furthermore, the variation of d(33,T perpendicular to) remained below 10% across the temperature range of 25-700 degrees 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.