Micromechanics of domain switching in rhombohedral PZT ceramics

The lattice strain epsilon{2 0 0} and diffraction peak intensity ratio R{1 1 1} have been determined in soft rhombobedral PZT ceramics during the application of an electric field up to 2.5 MV m(-1) and as a function of the grain orientation psi, using high energy synchtron X-ray diffraction. The magnitude of both epsilon {2 0 0} and R{1 1 1} increased sharply beyond a field level of 1 MV m(-1) due to the onset of ferroelectric domain switching. epsilon {2 0 0} exhibited a near linear dependence on cos(2) psi, in agreement with previous studies of the remanent-poled state. In contrast, the R{1 1 1}-cos(2) psi plot showed evidence of saturation in ferroelectric domain switching, particularly for psi > 60 degrees. The development of lattice strain during poling is discussed in terms of contributions from the intrinsic piezoelectric effect and from residual stress caused by differences in the poling strain of a grain, and the piezoelectric strain of a grain relative to its surroundings. (C) 2007 Elsevier Ltd and Techna Group S.r.l. All rights reserved.