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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 YbBa3(PO4)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 YbBa3(PO4)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 (d26∗ = 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 YbBa3(PO4)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 YbBa3(PO4)3 piezoelectric crystal is a promising candidate for high‐temperature piezoelectric sensing applications.

The fundamental shear horizontal (SH0) waves have been proved to be a very useful method for non-destructive testing due to their non-dispersive characteristics. Currently, although several methods have been proposed to generate SH0 waves, it is still a challenge to obtain pure SH0 wave mode efficiently. Herein, in this study, non-centrosymmetric YBa3(PO4)3 (YBP) and YbBa3(PO4)3 (YbBP) crystals with pure face-shear mode were grown via the traditional Czochralski pulling method at temperatures above 1800 °C. High resolution X-ray diffraction was carried out to evaluate the crystalline quality. Results showed that the YBP and YbBP crystals were of good quality, with the full width at half-maxima being on the order of 42.5″ and 52.3″, respectively. Moreover, the full set of electro-elastic constants for the YBP and YbBP crystals were determined and collated using a combination of impedance and pulse-echo methods. The piezoelectric coefficient (d14) of the YBP and YbBP crystals were determined to be 10.6 pC/N and 11.4 pC/N, respectively, corresponding to the electromechanical coupling coefficient (k14) equal to 15.4% and 15.9%, exhibiting large and pure face-shear vibration mode. Collectively, these results indicate that the YBP and YbBP crystals are promising for acoustic wave sensing application.

Piezoelectric materials are widely used in vibration sensors, pressure sensors and ultrasonic piezoelectric transducers etc. It is of great significance to explore novel piezoelectric crystal materials for using in special piezoelectric sensor devices. Herein, a novel non-centrosymmetric barium ytterbium phosphate (YbBa3(PO4)3,YbBP) piezoelectric crystal with high melting point (~1 800 ℃) was grown by traditional Czochralski method. The single crystal X-ray diffraction shows that this crystal belongs to the cubic symmetry with the space group of I43d and lattice parameters of a = b = c = 1. 043 5 nm. It is found that the YbBP single crystal is easier to grow along the direction perpendicular to the (013) facet. High resolution X-ray diffraction was carried out to evaluate the crystalline quality. The full width at half-maximum of rocking curves is 60. 6″, indicating that the grown YbBP single crystal shows good quality. Moreover, the dielectric permittivity and piezoele ctric constant were evaluated by using the LCR bridge method, impedance and ultrasonic methods. The relative dielectric permittivity (ε11) and piezoelectric strain constant (d14) of YbBP crystal are 15.3 and 11. 4 pC/N, respectively. The YbBP crystal not only possesses large piezoelectric performance but also has pure face-shear vibration mode, indicating the potentials of this crystal for piezoelectric sensing application. [ABSTRACT FROM AUTHOR]