Piezoelectricity in excess of 30 pC N−1 with a high Curie temperature of 950 °C in strongly textured CaBi2Nb2O9 ceramics

Abstract

CaBi₂Nb₂O₉ is a highly promising candidate for high-temperature piezoelectric devices due to its ultrahigh Curie temperature and excellent insulation properties. However, poor piezoelectric properties remain the primary reason for its limited application. In this work, the improved template grain growth method combined with a Na/Sm co-doping strategy was employed to enhance the piezoelectric properties of CaBi₂Nb₂O₉ ceramics. And the Na/Sm co-doped CaBi₂Nb₂O₉ textured ceramics with a high texture degree of 95–98% were successfully prepared, achieving the highest piezoelectric coefficient (d₃₃ > 30 pC N⁻¹) in the CaBi₂Nb₂O₉ ceramic systems, while maintaining a high DC electrical resistivity (>10⁷ Ω cm until 500 °C) as well as a high Curie temperature (T_C ∼ 950 °C). The dramatic improvement in d₃₃ is attributed to the great increase in remnant polarization, benefitting from the highly oriented arrangement of grains and the evolution of nanodomain configurations. This work achieves a breakthrough in the piezoelectric properties of CaBi₂Nb₂O₉-based ceramics and offers potential for their practical applications.