In situ observation of correlations between domain switching and crack propagation in BaTiO3 single crystals under coupling of mechanical and electric loads

Domain switching and crack propagation in BaTiO3 single crystals under external mechanical and electric load are observed directly by polarized light microscopy. The results show that the driving force for crack propagation is the incompatible strain induced by 90° domain switching due to electric load only or the coupling of mechanical and electric loads. The sequence and path of the crack propagation are related to the initial domain structure and the characteristics of the external load.