DIELECTRIC-PROPERTIES OF SINGLE GRAIN IN PLZT FERROELECTRIC CERAMICS

The hot pressed and grain-grown transparent ceramics with maximum grai n size 80 similar to 100 mu m provides the possibility of investigatin g the dielectric properties of single grain from ceramic specimens. Th e ion milling technique was employed to separate the grains. The diele ctric permittivities of single grain of PLZT have been measured. It is found that the range of dielectric constant of single grains in unpol ed state is larger than that of the bulk ceramic. Poling in both singl e grains and bulk ceramics reduces the dielectric constant in the poli ng direction, and increases it in the direction perpendicular to the p oling field. The anisotropy of dielectric permittivity for PLZT 8/65/3 5 is calculated from the single grain data.