An analytical axisymmetric model for the poling-history dependent behavior of ferroelectric ceramics

摘要

The poling-history dependent behavior of ferroelectric ceramics has been investigated by experimental tests. A suddenly poled ferroelectric ceramic was found to have significantly larger remnant polarization and strain than the corresponding values of a gradually poled one. To explain this phenomenon, a new domain-switching criterion for ferroelectric ceramics is proposed, in which each 180degrees switching is divided into two successive 90degrees switchings. In a suddenly poled ceramic, the strong intergranular interaction after the first 90degrees switching is favorable for accomplishing the second 90degrees switching. The effects of poling-dependent effects are then taken into account by evaluating different levels of energy dissipation after the first 90degrees switching. The domain orientation distribution function (ODF) as well as the macroscopic polarization and strain are analytically derived under cyclic electric loading. In the non-dissipation case, the macroscopic polarization of a ferroelectric ceramic can be ideally saturated as long as the magnitude of the applied electric field exceeds root2-E-C (E-C is the coercive field), while in the full dissipation case, the maximum macroscopic polarization is related to the magnitude of the applied electric field. The hysteresis loops for the non-dissipation case are almost identical to the corresponding loops of a suddenly poled ceramic, and the hysteresis loops for the full dissipation case are very close to those of a gradually poled ceramic. The good agreement between the analytical and experimental results indicates the validity of the proposed model in describing the poling-history dependent effects in ferroelectric ceramics.