Ultrasonic nonlinear properties of lead zirconate-titanate ceramics

Abstract

A systematic study of the nonlinear properties of lead zirconate-titanate (PZT) ceramics is presented. The velocity, attenuation, and nonlinearity parameter of PZT ceramics were measured from room temperature to temperatures above the Curie temperature. The velocity goes through a minimum near the Curie temperature. In spite of a maximum in attenuation near the Curie temperature, the nonlinearity parameter exhibits a maximum whose behavior is affected by polarization. Frequency dependence of the nonlinearity parameter at room temperature is reported for the first time. Large third harmonics of an initially sinusoidal ultrasonic wave at room temperature suggest that either the effect of the fourth-order elastic constants is anomalously large or that the nonlinear equation used to describe the behavior of single crystals is only approximately valid for description of PZT. Strain gradients are assumed to cause the frequency dependence of the nonlinearity parameter as well as the large third harmonic.