In this article, depolarization mechanisms under compressive stress were reported in ferroelectric materials. For this purpose, measurements were carried out at different scale (microscopic and macroscopic). The percentage of switched domains was calculated from x-ray diffraction diagrams for ceramics with rhombohedral symmetry and the polarization was simulated from these data. It has been underlined that depolarization is mainly caused by domain switching (i.e., extrinsic contribution) for both tetragonal and rhombohedral structures. A discussion on long range dipole-dipole is presented based on the assumptions made for polarization simulation. The main thermodynamic driving force for domain switching is thus shown to be only mechanical under compressive stress. As a consequence, tetragonal material is harder than rhombohedral one due to a larger domain switching induced strain.
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