A Calculation of the Electrostatic Interactions in Fine-Grained Perovskite Ferroelectric Ceramics.

摘要

The dielectric constants and spontaneous polarization of fine-grained pervoskite ferroelectric ceramics are calculated in terms of the dielectric constants and spontaneous polarization of the constituent crystallites. The latter set of constants are assumed to be those of a single crystal subjected to the same elastic stresses and electric field which a crystallite in a ceramic experiences. In this report,the electric field in a typical crystallite is also calculated,but the elastic stresses are treated in a companion report by Paul L. Smith and Jules de Launay. The values of the dielectric constants and spontaneous polarization of the ceramic also depend on the configuration of the c-axes of the crystallites. Consequently,the calculations are made for when the c-axes are randomly oriented,the c-axes are aligned as nearly as possible along the ceramic symmetry axis,the c-axes are randomly oriented except that no orientations of the second state mentioned above are occupied,and when the c-axes are aligned as nearly as possible to orientations parallel to the equatorial plane of the ceramic. (Author)