Real‐Time Ferroelectric Domain Wall Dynamics During Electric Poling and Depoling

Electrical poling protocols, including alternating current poling (ACP), direct current poling (DCP), and electrical depoling (EDP), are widely used to optimize the electromechanical properties of relaxor-lead titanate (PT) ferroelectric single crystals. However, the microscopic mechanisms governing their distinct outcomes remain unresolved, largely due to the lack of direct, real-time, and in-situ experimental access to domain wall dynamics during poling. As a result, competing interpretations based on domain refinement, domain coarsening, or polarization switching have emerged from ex-situ imaging and bulk-averaged electromechanical measurements. Here, we track domain wall-related birefringence dynamics in [110]-oriented lead indium niobate-lead magnesium niobate-lead titanate single crystals during ACP, DCP, and EDP using instant polarized light microscopy π (IPOLπ). This single-shot, non-destructive technique enables continuous, real-time tracking of domain wall nucleation, motion, and reconfiguration throughout the poling/depoling process. We reveal distinct, field-dependent dynamic pathways for different electrical protocols, demonstrating pronounced path dependence and reversibility that are not evident from static domain configurations alone. These results identify domain wall dynamics as the dominant mechanism governing electrical poling and depoling in relaxor-PT ferroelectrics and provide a dynamic framework for rational domain wall engineering in high-performance electromechanical materials.