Domain wall contributions to piezoelectricity in relaxor-lead titanate single crystals
Domain wall contributions to piezoelectricity in relaxor-lead titanate single crystals
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DOI：
10.1016/j.actamat.2020.05.034
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发表时间：
2020-08-15
期刊：
影响因子：
9.4
通讯作者：
Li, Yang
中科院分区：
文献类型：
--
作者：
Bell, Andrew J.;Shepley, Philippa M.;Li, Yang
结果表明，畴壁对弛豫型PbTiO 3单晶准同型相界（MPB）附近的介电常数和压电系数的贡献可以增大. Landau-Ginzburg-Devonshire模型将极化和应变梯度通过畴壁，表明畴工程单晶中的壁贡献源于静态畴壁中的增强的场致极化旋转，不像陶瓷，其中压电性通过畴壁平移增强。对于0.7Pb（Mg_（1/3）Nb_（2/3））O_（3 - 0.3PbTiO_（3））中的71度畴壁，在壁中心处的压电电荷系数d（33）取决于壁宽度从5000到> 30，000 pCN_1。因此，足够高的畴壁密度可以解释与单畴模型相比实验观察到的测量特性的增加。畴壁的对称性解释了在MPB附近观察到的各种平均对称性，以及实验观察到的[001]取向晶体通过对称性不可能的M c相转变为四方相。对于菱面体基态的晶体，畴壁的存在将赋予单斜对称性，其优势随着畴壁密度的增加而增加。(C)2020 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
It is demonstrated that the dielectric permittivity and piezoelectric coefficients in relaxor-PbTiO3 single crystals close to the morphotropic phase boundary (MPB) can be augmented by contributions from domain walls. Landau-Ginzburg-Devonshire models, incorporating both polarization and strain gradients through the domain walls, show that wall contributions in domain engineered single crystals originate from enhanced, field-induced polarization rotation in static domain walls, unlike ceramics, in which piezoelectricity is enhanced by domain wall translation. For 71 degrees domain walls in 0.7 Pb(Mg1/3Nb2/3)O-3 - 0.3PbTiO(3) the piezoelectric charge coefficient d(33) at the center of the wall ranges from 5000 to >30,000 pC N (1) depending on the wall width. Thus, a sufficiently high domain wall density can account for the experimentally observed augmentation in the measured properties compared to single domain models. The symmetry of the domain walls explains both the variety of average symmetries observed close to the MPB and the experimentally observed switching of the [001]-oriented crystals into the tetragonal phase via a symmetry-improbable M c phase. For a crystal of rhombohedral ground state, the presence of domain walls will impart monoclinic symmetry, the predominance of which increases with increasing domain wall density. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.