Abstract

This talk will describe recent theoretical and experimental investigations of domain switching in ferroelectric perovskites. The motivation for this work is actuator, sensor and optical applications. We begin with a theoretical model of single crystal materials, and use it to motivate an approach to large strain electrostriction under combined electro-mechanical loads. We describe the experimental set up and results that demonstrate this large strain electrostriction. We generalize the model to recognize the fact that ferroelectric materials are wide-band-gap semiconductors, and discuss its consequences on depletion layers, domain walls and defect diffusion. We then turn to ceramics or polycrystals. We present a theoretical analysis that shows that intergranular constraints against 90 degree domain switching depend on the symmetry of the material. This provides a new insight into the important of compositions in lead titanate zirconate. We close with some new ideas towards constructing tunable photonic devices using ferroelectric perovskites.