In situobservation of electric-field-induced domain switching near a crack tip in poled 0.62PbMg1∕3Nb2∕3O3–0.38PbTiO3 single crystal

An in situ polarized light microscopy observation of electric-field-induced domain switching near a crack tip in poled 0.62PbMg1∕3Nb2∕3O3–0.38PbTiO3 single crystal is reported. In-plane 90° domain switching is found to concentrate near the crack tip and the size of switching zone increases with the electric field. The polarization directions of switched domains, the positions, and width of 90° switching zones accord well with theoretical results based on the domain switching model by Hwang et al. [Acta Metall. Mater. 43, 2073 (1995)]. However, contradicting with this model, no explicit 180° domain switching ahead of the crack tip is observed.