Fatigue-induced evolution of domain structure in ferroelectric lead zirconate titanate ceramics investigated by piezoresponse force microscopy

The evolution of the domain structure in lead zirconate titanate ceramics in the course of polarization fatigue is investigated by piezoresponse force microscopy. It is found that fatigue results in a strong modification of the domain structure. The domain patterns initially consisting of mainly 180° domains split into fine ferroelastic domains to relieve the mechanical stresses arising due to the continuous polarization switching. The observed distorted domain walls (or "wavy" domain patterns) are attributed to clamping by defect agglomerates. The biggest concentration of clamped domains is found in grains close to the electrode interface signifying that these are most damaged by fatigue. Furthermore, a preferred polarization orientation is observed near the electrodes. Postannealing of fatigued samples promotes the partial recovery of the initial domain structure. The results indicate the importance of nearby electrode grains in the polarization switching in polycrystalline materials.