Crack tip 90° domain switching in tetragonal lanthanum-modified lead zirconate titanate under an electric field

Lanthanum-modified lead zirconate titanate ferroelectric ceramics (Pb0.96La0.04)(Zr0.04Ti0.06)(0.99)O-3 were synthesized by the conventional powder processing technique. X-ray diffraction experiments revealed that the samples belong to the tetragonal phase with a = b = 0.4055 nm, c = 0.4109 nm, and c/a = 1.013. After being poled, the samples were indented with a 5-kg, Vickers indenter, and lateral electric fields of 0.4 E-c, 0.5 E-c, and 0.6 E-c (E-c = 1100 V/mm) were applied, respectively. Field-emission scanning electron microscopy showed that 90 degrees domain switching appeared near the tip of the indentation crack under a lateral electric field of 0.6 E-c. A mechanism of 90 degrees domain switching near the crack tip under an electric field is discussed.