Synergy Ascension of Piezoresponse and Curie Temperature in Bismuth-layered Ceramics via Defect Engineering

Calcium bismuth niobate (CBN) has emerged as a promising candidate for ultrahigh-temperature piezoelectric applications, exhibiting the highest Curie temperature (T_C) among bismuth layer-structured ferroelectrics (BLSFs). Despite the conventional trade-off between piezoelectric coefficients (d₃₃) and T_C, this study demonstrates a novel 2D defect engineering optimization strategy for CBN ceramics that concurrently achieves a superior d₃₃ (> 20 pC/N) and maintains ultra-high T_C (> 960°C), as well as high electrical resistivity (> 10⁷ Ω·cm at 600°C). Through multi-scale microstructural analysis, optimized in-plane insulating properties and A-site defect orientation distribution promote an increase in spontaneous polarization and the formation of high-density multi-domain states, resulting in excellent electrical performance. Moreover, enhancement of lattice distortions induced by dipoles and the accompanying local electric field improve the stability of the ferroelectric phase and significantly elevate the T_C. This work presents a novel collaborative optimization approach for achieving exceptional overall performance within the Aurivillius compounds in future endeavors.