Inducing superior electrical performances in textured CaBi₂Ta₂O₉ based ceramics

Bismuth-layered structure ferroelectrics (BLSFs), exemplified by CaBi₂Ta₂O₉ (CBTa), exhibit exceptional thermal stability at high temperatures with a high Curie temperature. This attribute renders them highly promising candidates for piezoelectric sensors, transducers, non-volatile ferroelectric memory, etc. working in extreme environments. However, CBTa ceramic suffers from the following intrinsic limitations: spontaneous polarization confined within the ab-plane of the unit cell and a large coercive field, leading to severely suppressed piezoelectric activity (d₃₃ ≈ 5.4 pC N^-1). To address these challenges, a synergistic strategy integrating ion doping and hot forging is proposed to fabricate textured CBTa-based ceramics. Systematic characterization reveals that hot forging induces preferential grain orientation, effectively aligning polar domains while maintaining the layered perovskite structure. This optimization achieves significant enhancement in piezoelectric response (d₃₃ ∼ 21.8 pC N^-1) and direct-current resistivity (ρ > 1 × 10⁷ Ω cm at 600 °C) without compromising T_C (∼922 °C). Notably, the textured ceramics retain 95% of their initial piezoelectric performance after depoling at 900 °C for 2 h, underscoring their outstanding thermal stability. This work establishes a microstructure-engineering paradigm for tailoring electromechanical properties in BLSFs, bridging the gap between intrinsic material limitations and application-driven performance requirements.