Interaction of Ferroelectric Domain Walls and Shape of Equilibrium Repolarization Nuclei

The growth of a repolarization nucleus in an electric field is hindered by cohesive forces acting near its tips on the adjacent domain walls. They can take large values when the distance between domain walls becomes comparable to their thickness. It is shown that the cohesive forces are expressed via the coefficients of the Ginzburg–Landau energy expansion, which includes a gradient contribution. For a uniaxial ferroelectric, the maximum internal field associated with the gradient interaction of the domain walls has been estimated. It is related to the internal coercive field E_c0 of the Ginzburg–Landau theory as \({{E}_{{{\text{max}}}}}{\text{*}}\)/E_c0 = 3√3/8 ≈ 0.65.