Thickness-dependent domain wall reorientation in 70/30 lead magnesium niobate- lead titanate thin films
Thickness-dependent domain wall reorientation in 70/30 lead magnesium niobate- lead titanate thin films
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DOI：
10.1111/jace.14927
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发表时间：
2017-09-01
影响因子：
3.9
通讯作者：
Trolier-McKinstry, Susan
中科院分区：
文献类型：
--
作者：
Keech, Ryan;Morandi, Carl;Trolier-McKinstry, Susan
与许多基于铁电膜的技术相关的长度尺度的持续减小取决于随着膜厚度减小而保持功能性质。在100- 350 nm的厚度范围内研究了外延和多晶铅镁石-钛酸铅（70 PMN-30 PT）薄膜的界面和晶界低介电常数层对性能厚度依赖性的相对贡献。在SrRuO 3/（001）SrTiO 3衬底上生长了PMN-PT外延薄膜，在Pt/TiO 2/SiO2/Si衬底上用化学溶液沉积法生长了{001}-Lotgering因子>0.96的PMN-PT多晶薄膜。两种膜类型在高场下在具有高度结晶的电极/电介质界面的所有测量厚度下均表现出类似于300的类似相对介电常数。这些结果，与直流偏置和温度依赖性的介电特性，表明不可逆的畴壁迁移率是整体介电响应和其厚度依赖性的主要贡献者。在外延薄膜中，当厚度从350 nm减小到100 nm时，不可逆瑞利系数降低了85%。观察到的相对介电常数的峰值的温度是唯一测得的小信号量，这是更多的厚度依赖于多晶比外延膜。这归因于存在于膜中的弛豫性质，可能通过缺陷浓度和/或化学不均匀性来稳定。最后，有效的界面层被发现有助于测得的纵向压电系数的厚度依赖性。
Continued reduction in length scales associated with many ferroelectric film-based technologies is contingent on retaining the functional properties as the film thickness is reduced. Epitaxial and polycrystalline lead magnesium niobate-lead titanate (70PMN-30PT) thin films were studied over the thickness range of 100-350nm for the relative contributions to property thickness dependence from interfacial and grain-boundary low permittivity layers. Epitaxial PMN-PT films were grown on SrRuO3/(001)SrTiO3, while polycrystalline films with {001}-Lotgering factors >0.96 were grown on Pt/TiO2/SiO2/Si substrates via chemical solution deposition. Both film types exhibited similar relative permittivities of similar to 300 at high fields at all measured thicknesses with highly crystalline electrode/dielectric interfaces. These results, with the DC-biased and temperature-dependent dielectric characterization, suggest irreversible domain wall mobility is the major contributor to the overall dielectric response and its thickness dependence. In epitaxial films, the irreversible Rayleigh coefficients reduced 85% upon decreasing thickness from 350 to 100nm. The temperature at which a peak in the relative permittivity is observed was the only measured small signal quantity which was more thickness-dependent in polycrystalline than epitaxial films. This is attributed to the relaxor nature present in the films, potentially stabilized by defect concentrations, and/or chemical inhomogeneity. Finally, the effective interfacial layers are found to contribute to the measured thickness dependence in the longitudinal piezoelectric coefficient.