Department of Materials, Physics and Energy Engineering, Nagoya University, Chikusa, Nagoya, Aichi Pref. 464-8603, Japan.
Microsc Microanal. 2013 Dec;19(6):1586-94. doi: 10.1017/S1431927613013214. Epub 2013 Aug 29.
Electron energy-loss spectroscopy (EELS) attached to current transmission electron microscopes can probe not only element-selective chemical information, but also site-selective information that depends on the position that a specific element occupies in a crystal lattice. The latter information is exploited by utilizing the Bloch waves symmetry in the crystal, which changes with its orientation with respect to the incident electron wave (electron channeling). We demonstrate the orientation dependence of the cross-section of the electron energy-loss near-edge structure for particular crystalline sites of spinel ferrites, by quantitatively taking into account the dynamical diffraction effects with a large number of the diffracted beams. The theoretical results are consistent with a set of experiments in which the transition metal sites in spinel crystal structures are selectively excited. A new measurement scheme for site-selective EELS using a two-dimensional position-sensitive detector is proposed and validated by theoretical predictions and trial experiments.
电子能量损失谱（EELS）与电流传输电子显微镜相结合，不仅可以探测元素选择性的化学信息，还可以探测取决于特定元素在晶格中占据位置的位置选择性信息。后者的信息是通过利用晶体中的布洛赫波对称性来利用的，这种对称性随其相对于入射电子波的取向（电子通道）而变化。我们通过定量考虑大量衍射束的动力学衍射效应，证明了尖晶石铁氧体中特定晶体位置的电子能量损失近边结构截面的取向依赖性。理论结果与一组实验一致，其中尖晶石晶体结构中的过渡金属位置被选择性激发。提出了一种使用二维位置灵敏探测器进行位置选择性 EELS 的新测量方案，并通过理论预测和试验进行了验证。
