Ultrasonic investigation of nonlinear properties of PZT ceramics

The authors give an analysis of the nonlinear properties of lead zirconate titanate (PZT) ceramics and their relationship with the piezoelectric terms. Two different types of poled PZT ceramics were studied by propagating ultrasonic waves parallel to and perpendicular to the polarization direction. The propagation of such waves is nonlinear because of the structure of the medium, which can be described through the introduction of higher-order material constants. The nonlinear terms must be taken into account because their effect on the solution is amplitude dependent, and real waves have a finite amplitude. Similar measurements were made in unpolarized samples. The amplitudes of both the fundamental and the second harmonic of an initially sinusoidal ultrasonic wave were measured in order to estimate the effect of piezoelectricity on the effective third-order elastic constants of PZT ceramics