Chromium‐substituted bismuth titanate–niobate exhibiting superior piezoelectric performance for high‐temperature applications

Abstract High‐temperature piezoelectric ceramics with excellent piezoelectric properties are key materials for high‐temperature piezoelectric devices. In this context, bismuth titanate–niobate (Bi 3 TiNbO 9 ) is one of the most promising candidates, owing to its high Curie temperature ( T C ) > 900°C. However, the relatively low piezoelectric response of prototype Bi 3 TiNbO 9 does not satisfy the requirements of high‐precision and high‐sensitivity applications. Herein, chromium‐substituted Bi 3 TiNbO 9 with a nominal composition, Bi 3 Ti 1− x Cr x NbO 9 (BTN‐100 x Cr), was prepared using the solid‐state reaction method. Raman spectroscopy and X‐ray diffraction refinements revealed structural distortions induced by the substitution of chromium. Piezo‐response force microscopy and ferroelectric hysteresis loops showed facile polarization reversal and domain wall movement in chromium‐substituted Bi 3 TiNbO 9 . The resultant structural distortion and domain wall movement served as intrinsic and extrinsic contributions to the enhancement of the piezoelectric properties, respectively. Consequently, BTN‐1.5Cr exhibits a high piezoelectric constant ( d 33 ) of 17.7 pC/N, which is four times that of Bi 3 TiNbO 9 (4.2 pC/N), a high T C of 908°C, and an excellent thermal stability of piezoelectric and electromechanical coupling properties up to 500°C. These results indicate that chromium substitution enhances the high‐temperature piezoelectric properties of Bi 3 TiNbO 9 , and chromium‐substituted Bi 3 TiNbO 9 is a promising candidate for high‐temperature piezoelectric applications.