CPM Seminar

Domain switching and its applications in ferroelectric perovskites

Kaushik Bhattacharya

Caltech

Ferroelectric materials are spontaneously electrically polarized crystalline solids. They are widely used for their piezoelectric properties as actuators and sensors. Symmetry breaking at the Curie temperature results in multiple spontaneously electrically polarized and mechanically distorted states in a ferroelectric perovskite. These states coexist in characteristic domain patterns, and can switch from one state to another depending on the applied electrical and mechanical boundary conditions. Interestingly, domain switching forms the basis of important nonlinear properties. This talk will describe an effort that explicitly exploits domain switching in ferroelectric perovskites to create materials capable of large electrostriction against significant forces. We will describe the theoretical background and the experimental validation in bulk materials. We will then describe how this approach can be adopted to thin films in geometries that can be obtained by standard micromachining tools, issues related to materials integration and the experimental validation. We conclude by discussing polycrystalline ceramics and new ideas for exploiting domain switching in photonic devices.