INTRINSIC AND EXTRINSIC SIZE EFFECTS IN FINE-GRAINED MORPHOTROPIC-PHASE-BOUNDARY LEAD-ZIRCONATE-TITANATE CERAMICS

The processing, electromechanical properties, and microstructure of le ad zirconate titanate (PZT) ceramics over the grain-size range of 0.1- 10 mu m were studied. Using measurements over a large temperature rang e (15-600 K), the relative role of extrinsic contribution (i.e., domai n-wall motion) was deduced to be influenced strongly by the grain size , particularly for donor-doped PZT, Analytical transmission electron m icroscopy studies were conducted to investigate the trend in domain co nfigurations with the reduction of grain size, The correlations betwee n domain density, domain variants, domain configurations (before and a fter poling), spontaneous deformation, and the elastodielectric proper ties were qualitatively discussed, leading to new insights into the in trinsic and extrinsic effects and relevant size effects in ferroelectr ic polycrystalline materials.