Collective dynamics underpins Rayleigh behavior in disordered polycrystalline ferroelectrics
Collective dynamics underpins Rayleigh behavior in disordered polycrystalline ferroelectrics
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DOI：
10.1073/pnas.0913172107
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发表时间：
2010-04-20
影响因子：
11.1
通讯作者：
Kalinin, S. V.
中科院分区：
文献类型：
--
作者：
Bintachitt, P.;Jesse, S.;Kalinin, S. V.
纳米尺度和介观无序以及相关的局部滞后响应是自旋和团簇玻璃、相分离氧化物、多晶铁电体和铁磁体的独特性质的基础。尽管该领域有着丰富的历史，但滞后行为的统计描述符（如Preisach密度）与微观和纳米结构之间的关系仍然难以捉摸。通过使用多晶铁电电容器作为模型系统，我们现在报告了0.025-1 μ m(3)体积的定量非线性测量，比以前可能的小大约106倍。我们发现，随着厚度的增加，非线性行为的开始是由于嵌入在较弱非线性矩阵中的具有较大非线性响应的微米尺度区域的形成和面密度的增加。这一观察结果表明，与非相互作用壁的运动相反，大规模的集体畴壁动力学是无序铁电体中瑞利行为的基础。这些测量结果为铁电材料中畴雪崩的存在和程度提供了证据，迫使我们重新思考100年来的范式。
Nanoscale and mesoscopic disorder and associated local hysteretic responses underpin the unique properties of spin and cluster glasses, phase-separated oxides, polycrystalline ferroelectrics, and ferromagnets alike. Despite the rich history of the field, the relationship between the statistical descriptors of hysteresis behavior such as Preisach density, and micro and nanostructure has remained elusive. By using polycrystalline ferroelectric capacitors as a model system, we now report quantitative nonlinearity measurements in 0.025-1 mu m(3) volumes, approximately 106 times smaller than previously possible. We discover that the onset of nonlinear behavior with thickness proceeds through formation and increase of areal density of micron-scale regions with large nonlinear response embedded in a more weakly nonlinear matrix. This observation indicates that large-scale collective domain wall dynamics, as opposed to motion of noninteracting walls, underpins Rayleigh behavior in disordered ferroelectrics. The measurements provide evidence for the existence and extent of the domain avalanches in ferroelectric materials, forcing us to rethink 100-year old paradigms.