Strain-Gradient-Controlled Disorder Dynamics in Chemically Substituted Ferroelectrics

Abstract

A strain gradient $\ensuremath{\nabla}S$ deeply influences the properties of a disordered ferroelectric, but the exact mechanism whereby $\ensuremath{\nabla}S$ controls the disorder dynamics, especially in bulk material, is still largely unknown. The authors create a macroscopic strain gradient in KTa${}_{1\ensuremath{-}x}$Nb${}_{x}$O${}_{3}$ single crystals by coupling a composition gradient and 180\ifmmode^\circ\else\textdegree\fi{} domains, and field-dependent electro-optic effects reveal the $\ensuremath{\nabla}S$-controlled disorder dynamics and local dipole behaviors. This work provides a basis for understanding and harnessing the potential of disordered ferroelectrics, and the $\ensuremath{\nabla}S$ design method is valuable for developing functional materials and devices.