Well-defined double hysteresis loop in NaNbO3 antiferroelectrics
Nengneng Luo, Li Ma, Gengguang Luo, Chao Xu, Lixiang Rao, Zhengu Chen, Zhenyong Cen, Qin Feng, Xiyong Chen, Toyohisa Fujita, Ye Zhu, Jiawang Hong, Jing‐Feng Li, Shujun Zhang
Abstract
Abstract Antiferroelectrics (AFEs) are promising candidates in energy-storage capacitors, electrocaloric solid-cooling, and displacement transducers. As an actively studied lead-free antiferroelectric (AFE) material, NaNbO 3 has long suffered from its ferroelectric (FE)-like polarization-electric field ( P - E ) hysteresis loops with high remnant polarization and large hysteresis. Guided by theoretical calculations, a new strategy of reducing the oxygen octahedral tilting angle is proposed to stabilize the AFE P phase (Space group Pbma) of NaNbO 3 . To validate this, we judiciously introduced CaHfO 3 with a low Goldschmidt tolerance factor and AgNbO 3 with a low electronegativity difference into NaNbO 3 , the decreased cation displacements and [BO 6 ] octahedral tilting angles were confirmed by Synchrotron X-ray powder diffraction and aberration-corrected scanning transmission electron microscopy. Of particular importance is that the 0.75NaNbO 3 −0.20AgNbO 3 −0.05CaHfO 3 ceramic exhibits highly reversible phase transition between the AFE and FE states, showing well-defined double P - E loops and sprout-shaped strain-electric field curves with reduced hysteresis, low remnant polarization, high AFE-FE phase transition field, and zero negative strain. Our work provides a new strategy for designing NaNbO 3 -based AFE material with well-defined double P - E loops, which can also be extended to discover a variety of new lead-free AFEs.