THE EXTRINSIC NATURE OF NONLINEAR BEHAVIOR OBSERVED IN LEAD ZIRCONATE TITANATE FERROELECTRIC CERAMIC

The nonlinear electric and electromechanical responses of lead zirconate titanate Pb(Zr(x)Ti1-x)O3 ceramics to an external ac electric field have been measured under different driving levels. The onset of measurable nonlinearity is observed to be accompanied by the appearance of hysteresis loops. This lossy nature suggests that the nonlinearities in a ferroelectric ceramic are generated by the domain-wall motion. In addition, aging experiments and the bias field dependence of the threshold field (onset of nonlinearity) all indicate the extrinsic nature of the nonlinear behavior of ferroelectric ceramics. A phenomenological theory of Arlt, Dederichs, and Herbiet [Ferroelectrics 74, 34 (1987)] has been extended to include the nonlinear contributions. With only 90-degrees wall vibration being considered, the theory leads to some basic understanding of the experimental results.