Comparison of ferroelectric domain assemblages in Pb(Zr,Ti)O3 thin films and bulk ceramics

Ferroelectric domain assemblages of bulk and thin film Pb(Zr,Ti)O-3 (PZT) ceramics are characterized as a function of grain size. Specifically, domain morphologies of chemically prepared, bulk PZT 95/5 (rhombohedral symmetry) ceramics are compared to tetragonally distorted perovskite PZT thin films of composition ranging from PZT 20/80 to PZT 53/47. Transmission electron microscopy (TEM), electron channel contrast imaging (ECCI) and backscattered electron Kikuchi patterns (BEKP) are the primary means of structural characterization. Domain morphologies in TEM foils, which have minimal mechanical constraints, are to first order very similar to domain morphologies determined by ECCI of PZT thin films mechanically constrained to substrates and to those of bulk ceramics exhibiting internal stress. While quasistatic 90 degrees type domain patterns as a function of grain size are similar for both bulk and thin film ferroelectrics, 90 degrees domain dynamics are substantially different for PZT thin film and bulk materials. 90 degrees type domains are readily mobile under an applied electric field in large grain, bulk ceramics, but movement of these 90 degrees type domains is shown to be severely limited in PZT thin films.