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 (Bi₃TiNbO₉) 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 Bi₃TiNbO₉ does not satisfy the requirements of high-precision and high-sensitivity applications. Herein, chromium-substituted Bi₃TiNbO₉ with a nominal composition, Bi₃Ti_1−xCr_xNbO₉ (BTN-100xCr), 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 Bi₃TiNbO₉. 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 (d₃₃) of 17.7 pC/N, which is four times that of Bi₃TiNbO₉ (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 Bi₃TiNbO₉, and chromium-substituted Bi₃TiNbO₉ is a promising candidate for high-temperature piezoelectric applications.