Effects of the lapped surface layer and surface stress on the dielectric properties on PLZT ceramics

This paper reports the effects of surface layer and surface stress on the dielectric properties of PLZT ferroelectric ceramics studied. The specimens with surfaces prepared by grinding and polishing showed anomalous dielectric properties, i.e. smaller dielectric constant, lower dielectric loss below Curie temperature and smaller polarization than those of the specimens whose lapped surface layers were removed by chemical etching. After annealing at 650 degrees C for 1 hr, the dielectric properties showed improved values; the behavior may be attributed to the existence of surface layers produced during grinding and polishing which seem to be nonferroelectric in nature while under 2-D tensile stress, and having large capacitance of the order of 0.1 - 1.0 μF/cm2