Kimoto Koji, Ishizuka Kazuo, Mizoguchi Teruyasu, Tanaka Isao, Matsui Yoshio
Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan.
J Electron Microsc (Tokyo). 2003;52(3):299-303. doi: 10.1093/jmicro/52.3.299.
Resolution-enhancement software and first-principles calculation for electron energy-loss spectroscopy (EELS) were applied for the study of aluminium (Al) coordination in alumina. Al-L23 energy-loss near-edge structures (ELNES) of alpha- and gamma-aluminas were observed using a field-emission transmission electron microscope and advanced software for EELS. The inherent energy resolution of a cold field-emission gun (FEG) of approximately 0.3 eV was realized using drift-correction software. The energy spread of the cold FEG was deconvoluted by means of maximum-entropy or Richardson-Lucy algorithms and the energy resolution of the deconvoluted spectrum became comparable with that obtained using a monochromator, whose energy resolution was < 0.2 eV. Fine structures in Al L23-edge were observed, such as 0.5 eV splitting between L3 and L2 peaks in alpha-alumina (i.e. spin-orbit splitting). The difference in Al coordination was clearly observed in Al-L23 ELNES and the major structures near the threshold were assigned using first-principles calculations.
用于电子能量损失谱（EELS）的分辨率增强软件和第一性原理计算被应用于研究氧化铝中铝（Al）的配位情况。使用场发射透射电子显微镜和先进的EELS软件观察了α-氧化铝和γ-氧化铝的Al-L23能量损失近边结构（ELNES）。通过漂移校正软件实现了冷场发射枪（FEG）约0.3 eV的固有能量分辨率。利用最大熵或理查森-露西算法对冷FEG的能量展宽进行去卷积，去卷积谱的能量分辨率变得与使用能量分辨率<0.2 eV的单色仪获得的分辨率相当。观察到Al L23边的精细结构，如α-氧化铝中L3和L2峰之间0.5 eV的分裂（即自旋轨道分裂）。在Al-L23 ELNES中清楚地观察到Al配位的差异，并使用第一性原理计算确定了阈值附近的主要结构。
