Inhomogeneous domain switching near an electrode edge in orthorhombic K_0.5Na_0.5NbO₃ piezoceramic

To characterize the inhomogeneous field distributions and their effect on ferroelectric/ferroelastic domain switching in potassium sodium niobate-based piezoceramics, a partially electroded orthorhombic phase K_0.5Na_0.5NbO₃ ceramic sample containing a distinct edge was investigated using micro-beam, high-energy XRD with applied fields. Under the field application, the partial-electrode sample exhibits orientation-dependent and position-sensitive domain switching. The experimental measurements of micro-scale domain texture correlate reasonably with simulated electric fields calculated from a finite element analysis. Both experimental and simulated results reveal that the domain switching is induced inhomogeneously up to the millimeter-scale across the sample and that the electric field is significantly concentrated near the electrode edge. Integrating the experimental results with the model demonstrates that the local electric field directions and amplitudes drive the local orientation dependence of domain switching and, conversely, the direction of the local electric field can be inferred from the direction in which the maximum domain switching is measured.