In-situ Raman Observation of Domain Switching near Crack Tip in PLZT Ferroelectric Ceramics

Lanthanum-doped lead zirconate titanate (PLZT) ferroelectric ceramics with average grain size of 5 mm and a tetragonal structure were prepared by the conventional solid state reaction method, and then were surface coated with silver and pre-polarized in tangential direction. Then a groove was etched in the silvered surface of the ceramics, sbsequently Vickers indentation was introduced on the groove surface and external electric field was applied along the pre-polarization direction. The domain switching at different positions near the indentation crack tips were in-situ observed by Raman spectroscopy. The variation of the peak intensity of Raman soft modes of E(2TO) and E(3TO+2LO)+B1 versus the observation point was analyzed. The results show that the electric induced strain and 90° domain switching occurred at crack tips under the external electric field. The peak intensity of Raman spectrum and soft modes of E(2TO) and E(3TO+2LO)+B1 decreased with the distance between observation point and crack tip increasing.