Characterizing oxygen atoms in perovskite and pyrochlore oxides using ADF-STEM at a resolution of a few tens of picometers
Characterizing oxygen atoms in perovskite and pyrochlore oxides using ADF-STEM at a resolution of a few tens of picometers
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DOI：
10.1016/j.actamat.2021.116717
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发表时间：
2021-02
期刊：
影响因子：
9.4
通讯作者：
A. Mostaed;B. Walkley;M. Hatnean;G. Balakrishnan;M. Lees;R. Beanland;D. Sinclair;I. Reaney
中科院分区：
文献类型：
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作者：
A. Mostaed;B. Walkley;M. Hatnean;G. Balakrishnan;M. Lees;R. Beanland;D. Sinclair;I. Reaney
我们提出了一个像差校正扫描透射电子显微镜（ac-STEM）分析钙钛矿（LaFeO 3）和烧绿石（Yb 2 Ti 2 O 7和Pr 2 Zr 2 O 7）氧化物，并证明了在环形暗场（ADF）图像中可见原子柱的形状和对比度对附近低原子序数（如氧）原子的存在是敏感的。我们发现，点缺陷（如氧空位），这是不可见的-或难以观察到由于有限的灵敏度-在X射线和中子衍射测量，是复杂的磁基态的烧绿石氧化物的起源。此外，我们提出了一种方法，通过该方法可以在定量ADF-STEM图像中分辨轻原子。利用这种方法，我们解决了钙钛矿和烧绿石氧化物中的氧原子，并提出这种方法适用于其他材料包含轻和重元素。
We present an aberration corrected scanning transmission electron microscopy (ac-STEM) analysis of perovskite (LaFeO3) and pyrochlore (Yb2Ti2O7and Pr2Zr2O7) oxides and demonstrate that both the shape and contrast of visible atomic columns in annular dark-field (ADF) images are sensitive to the presence of nearby atoms of low atomic number (e.g. oxygen). We show that point defects (e.g. oxygen vacancies), which are invisible – or difficult to observe due to limited sensitivity – in x-ray and neutron diffraction measurements, are the origin of the complex magnetic ground state of pyrochlore oxides. In addition, we present a method by which light atoms can be resolved in the quantitative ADF-STEM images. Using this method, we resolved oxygen atoms in perovskite and pyrochlore oxides and propose this method to be suitable for other materials containing both light and heavy elements.