Electric-field-induced phase switching in the lead free piezoelectric potassium sodium bismuth titanate

High-energy synchrotron radiation has been used to demonstrate an electric-field-induced phase transformation in the ceramic xK1/2Bi1/2TiO3–(1−x)Na1/2Bi1/2TiO3, x=0.2. Application of an electric field ≥2 kV mm−1 leads to a transformation from single phase rhombohedral to a mixture of tetragonal and rhombohedral phases. The texturing of the tetragonal phase increases with field strength. The electric-field-induced transformation suggests an excursion into the morphotropic phase boundary in this system. The compositions x=0.1 and 0.3 reveal rhombohedral and tetragonal symmetry, respectively, both before and after the application of an electric field.