Properties of novel CaBi2Ta2O9-(Na0.5Bi0.5)Bi2Ta2O9 solid solution-based high Curie temperature piezoelectric ceramics

Abstract

Designing ferroelectrics with excellent electrical performance and high-temperature electrical resistivity (ρ) without severely sacrificing their high Curie temperature (TC) is a major issue in the development of Bismuth Layer-Structured Ferroelectrics (BLSFs). In this regard, a novel solid solution of CaBi2Ta2O9 and Na0.5Bi2.5Ta2O9 was synthesized by conventional electroceramic procedures in this study and was found to possess enhanced piezoelectric and ferroelectric properties together with a high Curie temperature (TC ∼ 925 °C). Further addition of (Li0.5Ce0.5)2+ not only elevated its piezoelectric constant (d33 ∼ 13.3 pC/N) and remnant polarization (Pr ∼ 7.2 μC/cm2) but also increased its high-temperature electrical resistivity (ρ > 108 Ω∙cm at 500 °C and ∼107 Ω∙cm at 600 °C) by more than one order of magnitude when compared with that of other BLSFs. Moreover, the CNBT-LC4 sample maintained 92% of its initial value after depoling at 900 °C and maintained its piezoelectric performance in the following annealing runs. These results demonstrate that Ca0.5(NaBi)0.25-x/2(LiCe)x/2Bi2Ta2O9 ceramics are promising candidates for future applications.