Ferroelectric properties are governed by domain structures and domain wall motions, so it is of significance to understand domain evolution processes under mechanical stress. In the present study, in situ piezoresponse force microscopy (PFM) observation under compressive stress was carried out for a near-morphotropic PZT. Both 180° and non-180° domain structures were observed from PFM images, and their habit planes were identified using electron backscatter diffraction in conjunction with PFM data. By externally applied mechanical stress, needle-like non-180° domain patterns were broadened via domain wall motions. This was interpreted via phenomenological approach such that the total energy minimization can be achieved by domain wall motion rather than domain nucleation mainly due to the local gradient energy. Meanwhile, no motion was observed from curvy 180° domain walls under the mechanical stress, validating that 180° domain walls are not directly influenced by mechanical stress.

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