Measurements of face shear properties in relaxor-PbTiO₃ single crystals

The face (contour) shear piezoelectric properties of Pb(Mg _1/3Nb_2/3)O_3-PbTiO₃ (PMNT) single crystals were experimentally determined by the impedance method. Zt ± 45 cut samples with various aspect ratios were investigated based on Bechmann's zero-order approximate solution. Square plates were found to exhibit a clean face shear vibration mode and the experimental data were in good agreement with the rotated matrix calculations and finite element method simulations. The piezoelectric coefficients d₃₆ were determined to be in the range of 1600-2800 pC/N, depending on the compositional variations, with an ultralow frequency constant N₃₆, in the range of 490-630 Hz.m. In contrast to conventional thickness shear modes, the mechanical quality factors of face shear vibrations are relatively high, with Q values being on the order of ∼100-450, demonstrate promising for low frequency transducer applications.