Electro-elastic features of YBa3(PO4)3 and YbBa3(PO4)3 crystals with pure face-shear mode for acoustic wave sensor 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.