Near stoichiometric lithium niobate crystal with dramatically enhanced piezoelectric performance for high temperature acceleration sensing

Abstract

Lithium niobate (LN) is a multifunctional crystal with excellent piezoelectric properties, making it a potential candidate for piezoelectric sensing applications. In this study, the mechanism of the discrepancies of piezoelectric properties between near stoichiometric lithium niobate (NSLN) and congruent lithium niobate (CLN) were probed using Raman spectrum, first principle calculations and single crystal X-ray diffraction (XRD), where the 〖V Li -〗 defect demonstrated a significant impact on the distortion of the NbO6 octahedron, which in turn affected the piezoelectric properties of the LN crystal. Among them, NSLN crystal was found to exhibit strong piezoelectric performance. It was confirmed that the NSLN crystal exhibited strong piezoelectric coefficients d15 and d22 on the orders of 77.6 pC N-1 and 22.8 pC N-1, respectively, showing improvements of 17.4% and 18.1% over the CLN crystal, highlighting its enhanced piezoelectric characteristics. Finally, temperature dependent behaviours of the electro-elastic constants for the NSLN and CLN crystals were discussed. And the high temperature piezoelectric performance of NSLN crystal was evaluated utilizing a prototype of shear-mode acceleration sensor, demonstrating remarkable sensing performance up to 650 °C with good temperature stability (sensitivity variation <5%).