Acoustic anisotropy of piezoelectric PbB[sub 4]O[sub 7] crystals

The crystals of borate series are new nonlinear optical and piezoelectric crystals which have an extensive application prospect. In this paper, the acoustic anisotropic properties of PbB4O7 crystals are investigated and discussed. In the theory, the piezoelectric coupling between electromagnetic and acoustic uniform waves are completely negligible, i.e., the quasistatic approximation is used to solute piezoelectric waves propagation equations. The acoustic velocity and slowness curves of three bulk waves and surface wave in X-, Y- and Z-cut crystal planes are numerically calculated. Meanwhile, the theoretical results of the slowness curves are compared with that of the experimental measurement by laser ultrasonic technique. Both are in agreement with each other. On the other hand, the efficiencies of piezoelectric excitation of surface acoustic wave in different propagation directions of X-, Y-, Z- and 45° Y-cut crystal surfaces are theoretically evaluated. The results can be used for selecting the crysta...