Defect Pinning and Oxygen Octahedral Tilting Drive the Antiferroelectric‐Like Response in Relaxor Ferroelectrics

ABSTRACT The pursuit of high performance dielectric capacitors necessitates a deep understanding of the atomic‐scale mechanism governing their polarization response. Entropy engineering is an effective strategy for tuning polarization properties. In particular, introducing specific elements into medium/high‐entropy systems can induce an antiferroelectric‐like polarization‐electric field ( P‐E ) hysteresis loop, which is highly desirable for high energy storage performance due to its high maximum polarization and low remnant polarization. However, their atomic‐scale origin remains unclear. Herein, atomic‐scale transmission electron microscopy (TEM) analyses reveal that this distinctive behavior originates from the synergistic effect of dislocation pinning and oxygen octahedral tilting mode transition. The pinning effect inhibits polarization switching, causing a non‐overlapping P‐E loop, while oxygen octahedral tilting directly contributes to the pinched loop. The a 0 a 0 c – oxygen octahedral tilting mode stabilizes a relaxor state with low remnant polarization. In situ TEM characterization under an electric field demonstrates an electric field‐induced transformation of the oxygen octahedral tilting mode from a 0 a 0 c – to a 0 a 0 a 0 , directly correlating structural evolution with antiferroelectric‐like behavior. These findings deliver atomic‐scale insights that defect pinning and oxygen octahedral tilting induce antiferroelectric‐like behavior, offering a novel strategy for designing energy storage ceramics.