Enhanced piezoelectric properties and high electrical resistivity in (Li_0.5Pr_0.5) co-substituted bismuth calcium tantalate (CaBi₂Ta₂O₉) ceramics

Bismuth calcium tantalate (CaBi₂Ta₂O₉) ferroelectric ceramic has not been studied adequately though it shows potential applications in high-temperature piezoelectric devices due to its ultrahigh Curie temperature (T_C~929 °C). In this paper, (Li_0.5Pr_0.5) co-substitution at A site was proposed to increase piezoelectricity activity (d₃₃) and electrical resistivity (ρ) of CaBi₂Ta₂O₉-based ceramics and thereby a study of effect of the co-substitution on their structure and electrical properties was conducted. The composition Ca_1-x(Li_0.5Pr_0.5)_xBi₂Ta₂O_9+δ for x= 0.04 shows the highest d₃₃ of 15.1 pC/N which is about twice than that of CaBi₂Ta₂O₉. At 700 °C, ρ of this composition reaches up to 1.5 MΩ cm and hence the dielectric loss (tanδ) is lower than 3%. These results combined with high T_C (~925 °C) and stable d₃₃ (up to 800 °C), suggest that it is a very promising material for high-temperature piezoelectric applications at 700 °C or higher.