Subcritical growth of repolarization nuclei in polycrystalline ferroelectric films

The problem of subcritical growth of repolarization nuclei in ferroelectric crystals is considered. Following the approach of Barenblatt to the theory of equilibrium brittle cracks, a concept of cohesive forces, acting on adjacent domain walls in a region near the domain tip, is introduced. These cohesive forces are intimately related to the gradient term in the Ginzburg-Landau energy and become substantial as the separation between the domain walls compares with their thickness δ. The condition of equilibrium for a ferroelectric domain is formulated by taking into account the internal field associated with the cohesive forces. Criteria for stable subcritical growth of nuclei in non-uniform electric fields are presented in terms of a gradient modulus, which is an extension of the cohesion modulus concept of Barenblatt.

The article was prepared based on the report presented at the Symposium "Micromechanics of Functional Materials" at the XIII All-Russian Congress on Theoretical and Applied Mechanics.