Textured CaBi4Ti4O15 ceramics with large piezoelectricity, excellent thermal stability and high resistivity

The bismuth layer-structured ferroelectrics (BLSF) are promising high-temperature piezoelectric materials, in which large piezoelectricity, good thermal stability and high electrical resistivity are desired. Here highly textured CaBi4Ti4O15 BLSF ceramics with orientation factor of 82% have been fabricated by spark plasma sintering technique. The piezoelectric coefficient d33 is significantly enhanced by 250%, from 7.2 pC/N for the texture-less sample to 25.3 pC/N for the textured one, accompanied by a high Curie temperature TC= 788 °C. The variation of d33 is below 5% in the temperature range of 25–500 °C, showing excellent thermal stability. The textured sample exhibits high electrical resistivity ρ = 2.1 × 1011 Ω·cm, an order of magnitude larger than that of the texture-less sample. At the temperature as high as 500 °C, the textured sample still maintains excellent electrical properties of d33 = 24.2 pC/N, tanδ = 9.9% and ρ = 2.7 × 106 Ω·cm, suggesting that the textured CaBi4Ti4O15 ceramics could be a potential candidate for high-temperature piezoelectric sensor or detector applications.