A‐site engineered NaNbO₃ lead‐free antiferroelectrics toward well‐defined double hysteresis loop

Abstract NaNbO 3 ‐based lead‐free antiferroelectric (AFE) ceramics have long exhibited ferroelectric (FE)‐like polarization–electric field ( P – E ) hysteresis loops resulting from the irreversible transition of the AFEP‐phase to the FE Q‐phase. In this study, we demonstrated that the reversibility of the AFE–FE phase transition can be significantly enhanced via A‐site chemical substitution. Notably, the (Na 0.48 Ca 0.06 Ag 0.4 )NbO 3 ceramic exhibited well‐defined double P – E loops characterized by reduced hysteresis, low remnant polarization, and high electric field for the AFE–FE phase transition. The Ca 2+ and Ag + co‐modification was beneficial for stabilizing the AFE P‐phase, owing to the decrease in both the tolerance factor and the average electronegativity difference. Structural analysis revealed that A‐site cation displacement was substantially reduced via the A‐site ion modification. This study presents a new strategy for achieving reversible AFE‐to‐FE phase transitions with well‐defined double P – E loops in NaNbO 3 ‐based AFE materials, which can also be extended to discover a range of novel lead‐free AFEs.