Ultrahigh‐Temperature Piezoelectric Crystal YbBa₃(PO₄)₃ for Vibration Sensing Application

Abstract High‐temperature vibration sensors are of great importance for accurate monitoring of dynamic mechanical conditions in automotive, aerospace and energy‐generation‐related systems. Currently, piezoelectric crystals with ultrahigh operational temperature and good piezoelectric performance for high‐temperature sensing applications are attracting considerable attention. Herein, a novel piezoelectric crystal YbBa 3 (PO 4 ) 3 with cubic symmetry and a high melting point of ≈1850 °C is explored, and grown by using the Czochralski method. The temperature‐dependent behaviors of electro‐elastic constants and electrical resistivity are investigated ranging from 25 to 800 °C, where the dielectric loss of the YbBa 3 (PO 4 ) 3 crystal is found to be ≈15% at 800 °C. In addition, an optimal crystal cut with a pure thickness shear vibration mode is designed. The optimal crystal cut presents a good piezoelectric activity ( = 12.6 pC N −1 ) as well as good temperature stability. Furthermore, a high‐temperature accelerometer with shear piezoelectric mode is designed and fabricated using the YbBa 3 (PO 4 ) 3 crystal, and the sensing performance at elevated temperature are evaluated. The average sensitivity is found to be 1.16 pC g −1 , with a small temperature deviation (≈7.7%), exhibiting a good temperature stability. All these results indicate that YbBa 3 (PO 4 ) 3 piezoelectric crystal is a promising candidate for high‐temperature piezoelectric sensing applications.