Stable antiferroelectricity with incompletely reversible phase transition and low volume-strain contribution in BaZrO3 and CaZrO3 substituted NaNbO3 ceramics
Stable antiferroelectricity with incompletely reversible phase transition and low volume-strain contribution in BaZrO3 and CaZrO3 substituted NaNbO3 ceramics
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BaZrO3 和 CaZrO3 取代的 NaNbO3 陶瓷具有稳定的反铁电性、不完全可逆相变和低体积应变贡献
DOI：
10.1016/j.actamat.2018.09.056
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发表时间：
2018
期刊：
影响因子：
9.4
通讯作者：
Qi He
中科院分区：
文献类型：
--
作者：
Zuo Ruzhong;Fu Jian;Qi He
在这项工作中，一个可重复的双极化对电场（P-E）磁滞回线清楚地揭示了在6 mol% bazro3和3 mol% CaZrO3掺杂的NaNbO3（NN）样品中存在室温稳定的反铁电性（AFE）。应变-场（S-E）曲线不一致，但在第一周期和非第一周期之间没有任何负应变，但表现出不完全可逆的场诱导afe -铁电（FE）相变。原位/非原位同步辐射x射线衍射结果表明，在电循环前后，不可恢复的AFE状态分别具有正交和单斜结构，产生不可逆的应变贡献，包括不可逆的体积（22%）和晶格（78%）应变。P/S-E曲线的频率相关测量结果表明，在固定频率下，任何循环的应变回路中都等效地存在着由场致FE回切到AFE的时间效应所产生的剩余应变。与未循环样品相比，循环后的样品表现出完全可逆的单斜FE-单斜FE相变，但极化应变相对较小。特别值得注意的是，在AFE nn基陶瓷中，体积应变对极化应变的贡献仅为20%，其中纵向应变为正，横向应变为负，同时观察到，这挑战了传统pb基AFE陶瓷中两个方向的应变都应为正的常识。实验结果为神经网络的AFE相稳定性提供了新的见解，并为未来利用基于神经网络的反铁电陶瓷用于大位移执行器提供了令人兴奋的可能性。
In this work a reproducible double polarization versus electric field (P-E) hysteresis loop clearly reveals a room-temperature stable antiferroelectricity (AFE) in virgin NaNbO3(NN) samples doped with 6 mol% BaZrO3and 3 mol% CaZrO3. Inconsistent but sprout-like strain versus field (S-E) curves without any negative strains between the first and non-first cycles yet display an incompletely reversible field induced AFE-ferroelectric (FE) phase transition. In/ex-situ synchrotron x-ray diffraction results suggest irrecoverable AFE states with orthorhombic and monoclinic structures before and after electric cycling, respectively, which generate an irreversible strain contribution including both irreversible volume (22%) and lattice (78%) strains. Frequency-dependent measurements of P/S-E curves demonstrate the rest of remanent strains from the time effect of back-switching from field induced FE to AFE equivalently existing in strain loops of any cycles at a fixed frequency. Compared with virgin samples, post-cycled samples exhibit a completely reversible monoclinic AFE-monoclinic FE phase transition but a relatively small poling strain. It is of particular note that the contribution of the volume strain to the poling strain is only 20% in AFE NN-based ceramics, in which a positive longitudinal strain and a negative transverse strain are concurrently observed, challenging a common knowledge that both strains in two directions should be positive for traditional Pb-based AFE ceramics. The experimental results provide new insights into the AFE phase stability of NN and an exciting possibility to take advantage of NN-based antiferroelectric ceramics for large-displacement actuators in future.