Using aberration corrected STEM to study the atomic structure of incommensurate antiferroelectrics

使用像差校正 STEM 研究不相称反铁电体的原子结构

• 批准号: EP/I000879/1
• 负责人: Ian MacLaren
• 金额: $ 1.81万
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FI000879%2F1
• 关键词: Using; aberration; corrected; STEM; study

Some atomic structures are just not amenable to traditional diffraction-based solution using X-rays or neutrons. One example of this is irregular or disordered layered structures, where the disorder on the nanoscale makes any interpretation of diffraction data extremely difficult. This is exactly the situation in lanthanum-doped zirconium-rich lead zirconate titanate where the unit cells often appear to have a period in one direction which is not a simple multiple of the number of building blocks of simple cells that they are made of (i.e. the full cell is incommensurate with the primitive cell). It appears that this happens because different layered structures can be formed and they can be stacked together irregularly. In this situation, the only way to determine the local atomic structure is via an imaging based technique with atomic resolution.This project will use high resolution scanning transmission electron microscopy at the world-leading EPSRC-supported SuperSTEM facility, which can image features down to below 1 +. In particular, the samples will be imaged using the High Angle Annular Dark Field technique, which is especially sensitive to heavy elements and which will consequently be invaluable for locating Pb and Zr ions; this will provide a powerful complement to HRTEM investigations being performed separately (also funded by the EPSRC under Grant Reference EP/H028218/1) which is more sensitive to oxygen ion locations. Images from both techniques will then be analysed quantitatively to extract atom positions and using images from more than one direction, we will then determine the three dimensional atom positions in each stacking sequence. This will then enable us to understand how the polarisation is ordered within the different stacking in order to produce antiferroelectric structures. This will provide a powerful demonstration of the capabilities of aberration corrected STEM in conjunction with quantitative data analysis to analyse nanoscale structures with atomic resolution, and will also lay the groundwork for future work on electric field induced phase transformations and possible applications of antiferroelectric lead zirconate titanate compositions.

一些原子结构不适合使用X射线或中子的传统衍射解决方案。其中一个例子是不规则或无序的层状结构，其中纳米尺度上的无序使得衍射数据的任何解释都非常困难。这正是镧掺杂的富锆锆钛酸铅中的情况，其中单位电池通常看起来在一个方向上具有周期，该周期不是构成它们的简单电池的构建块的数量的简单倍数（即，全电池与原始电池不相称）。这似乎是因为可以形成不同的分层结构，并且它们可以不规则地堆叠在一起。在这种情况下，确定局部原子结构的唯一方法是通过具有原子分辨率的基于成像的技术。该项目将在世界领先的EPSRC支持的SuperSTEM设施中使用高分辨率扫描透射电子显微镜，其可以对低于1 +的特征进行成像。特别是，样品将使用高角度环形暗场技术成像，该技术对重元素特别敏感，因此对于定位Pb和Zr离子非常宝贵;这将为单独进行的HRTEM研究提供有力的补充（也由EPSRC在授权参考EP/H 028218/1下资助），该研究对氧离子位置更敏感。然后将对这两种技术的图像进行定量分析以提取原子位置，并使用来自多个方向的图像，然后我们将确定每个堆叠序列中的三维原子位置。这将使我们能够理解极化是如何在不同的堆叠中排列的，以产生反铁电结构。这将提供一个强有力的演示畸变校正干结合定量数据分析的能力，以分析纳米结构与原子分辨率，也将奠定基础，为未来的工作电场诱导相变和可能的应用反铁电锆钛酸铅组合物。

项目成果

Atomic scale structural and chemical quantification of non-stoichiometric defects in Ti and Nd doped BiFeO3

Ti 和 Nd 掺杂 BiFeO3 中非化学计量缺陷的原子尺度结构和化学定量

• 发表时间: 2011
• 作者: Bernhard Schaffer

Local stabilisation of polar order at charged antiphase boundaries in antiferroelectric (Bi0.85Nd0.15)(Ti0.1Fe0.9)O3

• DOI: 10.1063/1.4818002
• 发表时间: 2013-08
• 期刊: APL Materials
• 影响因子: 6.1
• 作者: I. MacLaren;Liqiu Wang;Owen P Morris;A. Craven;R. Stamps;B. Schaffer;Q. Ramasse;S. Miao;K. Kalantari;I. Sterianou;I. Reaney

The atomic structure and chemistry of Fe-rich steps on antiphase boundaries in Ti-doped Bi0.9Nd0.15FeO3

• DOI: 10.1063/1.4884684
• 发表时间: 2014-06
• 期刊: APL Materials
• 影响因子: 6.1
• 作者: I. MacLaren;Liqiu Wang;A. Craven;Q. Ramasse;B. Schaffer;K. Kalantari;I. Reaney

Novel Nanorod Precipitate Formation in Neodymium and Titanium Codoped Bismuth Ferrite

• DOI: 10.1002/adfm.201201835
• 发表时间: 2013-02-11
• 期刊: ADVANCED FUNCTIONAL MATERIALS
• 影响因子: 19
• 作者: MacLaren, Ian;Wang, Li Qiu;Reaney, Ian M.
• 通讯作者: Reaney, Ian M.

Defect chemistry of Ti-doped antiferroelectric Bi0.85Nd0.15FeO3

• DOI: 10.1063/1.4705431
• 发表时间: 2012-05
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: I. Reaney;I. MacLaren;Liqiu Wang;B. Schaffer;A. Craven;K. Kalantari;I. Sterianou;S. Miao;S. Karimi;D. Sinclair