Dynamic measurement of nonlinear constants of PZT ceramics

The dynamic measurement technique of adiabatic nonlinear constants in piezoelectric materials used in elastic devices is discussed. The present technique deals with the FM wave whose frequency varies corresponding to a physical quantity which changes sinusoidally. Using this method, measurements of a change in velocity and dielectric constant due to an applied ac electric field and also of a change in dielectric constant due to sinusoidally applied stress are made. In this method one can measure physical quantities depending on their orders responding to an applied field separately and can obtain constants of the orders (third of fourth order). Also, this technique can distinguish a change in velocity and dielectric constant due to temperature variation from those resulting from a nonlinear effect. Using this unique feature, measurements of velocity and dielectric constants with electric field at various temperatures were made. The temperature dependence of linear and nonlinear constants of the third and fourth order in PZT ceramics was discussed.