DYNAMIC METHOD FOR MEASURING THE VELOCITY VARIATION OF ULTRASOUND IN PIEZOELECTRIC CERAMICS WITH AN ALTERNATING ELECTRIC-FIELD

The development and application of a new dynamic measuring method of velocity variation of piezoelectric materials, especially of lead zirconate titanate (PZT) ceramics, with an alternating electric field is presented. This method has the following advantages over the conventional static method. (1) The velocity variation due to nonlinear effect is separable from the velocity variation due to temperature change. (2) The adiabatic nonlinear coefficients are obtainable. (3) In spite of the dynamic nature of the method, it fixes the sign of the nonlinear coefficient. (4) Separating the orders of the velocity variation as a function of the applied electric field, each order of coefficients is determinable.