Large piezoelectricity and high Curie temperature in novel bismuth ferrite-based ferroelectric ceramics

The requirement for ferroelectric ceramics with a high Curie temperature and a high piezoelectric coefficient remains an important research task for high-temperature sensors and actuators applications. (0.76-x)BiFeO 3- 0.24 PbTiO 3- x Ba(Sn 0.2 Ti 0.8 )O 3 (BF-PT-BST) piezoelectric ceramics were fabricated using the solid-state reaction method. XRD analysis indicated that the incorporation of large ionic radius Ba 2+ at A-site and nonferroelectric-active Sn 4+ at B-site generated a decrease in the tetragonality degree c/a. A wide multiphase coexistence region was formed with the content of BST ranging from 0.13 to 0.28. The enhanced piezoelectric coefficient ( d 33 ~ 200pC/N) was achieved while maintaining a high Curie temperature ( T C ~ 500°C) and a high depolarization temperature ( T d ~ 450°C) for the composition of 0.6BF-24PT-0.16BST. TEM patterns provided clear evidence for the presence of nanodomains (~2nm) would be the predominant source for the enhanced piezoelectricity for the composition x = 0.20. The designed BF-PT-BST ternary system provides great potential for high-temperature piezoelectric applications.