Strain-Gradient-Controlled Disorder Dynamics in Chemically Substituted Ferroelectrics

A strain gradient ∇S deeply influences the properties of a disordered ferroelectric, but the exact mechanism whereby ∇S controls the disorder dynamics, especially in bulk material, is still largely unknown. The authors create a macroscopic strain gradient in KTa_1-xNbₓO₃ single crystals by coupling a composition gradient and 180^∘{} domains, and field-dependent electro-optic effects reveal the ∇S-controlled disorder dynamics and local dipole behaviors. This work provides a basis for understanding and harnessing the potential of disordered ferroelectrics, and the ∇S design method is valuable for developing functional materials and devices.