Factors influencing the coupling between non-180° domain switching and lattice strain in perovskite piezoceramics

Abstract

Domain switching and lattice strain are known to be important processes contributing to the large electromechanical response observed in perovskite-based piezoelectrics. However, there is a lack of clarity regarding the coupling between the two phenomena, and the factors which influence this coupling. Here, we report a systematic investigation to understand the factors influencing the coupling between domain switching and lattice strain in perovskite piezoelectrics by x-ray diffraction in situ with electric field. In a slight departure from the conventional approach, we employ a strategy which enables x-ray diffraction study in situ with electric field on randomly oriented piezoelectric grains in their unclamped (free) state. Experiments were carried out on two different systems (1−x) PbTiO₃−(x) BiScO₃ and (1−x)PbTiO₃−(x) PbZrO₃ in their rhombohedral phase. We found that lattice strain along the nonpolar ⟨ 100 ⟩ R rhombohedral direction varies linearly with the non-180° domain switching fraction ( η 111 ) . We introduce a parameter β to characterize the strength of coupling between the two phenomena and show that the coupling is enhanced when the system approaches the morphotropic phase boundary. We also demonstrate that the grain-to-grain interaction nearly doubles this coupling in a dense piezoelectric ceramic.