Isolation of a ferroelectric intermediate phase in antiferroelectric dense sodium niobate ceramics
Isolation of a ferroelectric intermediate phase in antiferroelectric dense sodium niobate ceramics
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DOI：
10.1016/j.actamat.2019.08.038
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发表时间：
2019-10-15
期刊：
影响因子：
9.4
通讯作者：
Abrahams, Isaac
中科院分区：
文献类型：
--
作者：
Zhang, Hangfeng;Yang, Bin;Abrahams, Isaac
可开关铁电/反铁电陶瓷在大功率储能领域具有重要的应用价值。这种开关的晶粒度控制是一种有趣的方法来控制极化，从而控制介电性能。然而，这种方法在技术上相关的陶瓷中的使用由于难以制造致密的小颗粒陶瓷而受到阻碍。本文采用放电等离子烧结的方法控制晶粒度，在致密的块体Nb_2O_3陶瓷中分离出中间极性铁电相(P2(1)mA)。我们的发现得到了X射线衍射、DSC、P-E(I-E)环和介电特性的支持，证明了在室温下，从300℃以上Pnmm空间群的反铁电(AFE)R相到Pbma空间群的AFE P相的相变总是涉及到极性中间P2(1)ma相，并且可以通过减小晶粒尺寸来抑制P2(1)ma-Gt；Pbma相变。(C)2019 Acta Materialia Inc.由Elsevier Ltd.出版。保留所有权利。
Switchable ferroelectric/antiferroelectric ceramics are of significant interest for high power energy storage applications. Grain size control of this switching is an interesting approach to controlling polarization and hence dielectric properties. However, the use of this approach in technologically relevant ceramics is hindered by difficulty in fabricating dense ceramics with small grain sizes. Here an intermediate polar ferroelectric phase (P2(1)ma) has been isolated in dense bulk sodium niobate ceramics by grain size control through spark plasma sintering methods. Our findings, supported by XRD, DSC, P-E (I-E) loops and dielectric characterization, provide evidence that the phase transition from the antiferroelectric (AFE) R-phase, in space group Pnmm, above 300 degrees C, to the AFE P-phase, in space group Pbma, at room temperature, always involves the polar intermediate P2(1)ma phase and that the P2(1)ma -> Pbma transition can be suppressed by reducing grain size. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.