Mesoscale Domain Evolution Mechanism during Alternating Current (AC) Poling of Relaxor Ferroelectrics

ABSTRACT

Ferroelectric domain variants that are energetically equivalent are expected to remain preserved during polarization reversal under a symmetry‐preserving electric field. However, recent experiments on relaxor–ferroelectric crystals have revealed irreversible elimination of inclined domain walls during AC poling, while the underlying mesoscale mechanism remains unclear. Here, we investigate domain‐wall motion during AC poling of rhombohedral Pb()– single crystals containing 71 and 109 domain walls within a quasi‐two‐dimensional laminated geometry using phase‐field simulations. Simulations reveal that domain‐wall behavior during polarization reversal depends on the spacing ratio between 71 and 109 domain walls. Closely spaced 71 domain walls undergo irreversible elimination, whereas widely separated walls are preserved. A threshold ratio for domain‐wall elimination is identified and found to depend on mechanical boundary conditions. By tracking domain‐wall trajectories, we attribute this behavior to unsynchronized motion of neighboring 71 domain walls arising from long‐range elastic interactions when walls become strongly coupled. This collective motion breaks the symmetry between domain variants and leads to irreversible domain‐wall elimination. These findings provide mechanistic insight into collective domain‐wall evolution during polarization reversal and suggest that proximity‐driven symmetry breaking may provide a mesoscale mechanism for domain engineering in ferroelectrics with high domain‐wall densities.