DIELECTRIC-PROPERTIES OF SINGLE GRAIN IN PLZT FERROELECTRIC CERAMICS

The hot pressed and grain-grown transparent ceramics with maximum grain size 80 similar to 100 mu m provides the possibility of investigating the dielectric properties of single grain from ceramic specimens. The ion milling technique was employed to separate the grains. The dielectric permittivities of single grain of PLZT have been measured. It is found that the range of dielectric constant of single grains in unpoled state is larger than that of the bulk ceramic. Poling in both single grains and bulk ceramics reduces the dielectric constant in the poling direction, and increases it in the direction perpendicular to the poling field. The anisotropy of dielectric permittivity for PLZT 8/65/35 is calculated from the single grain data.