Quantitative analysis of materials by new electron microscopy technique

开发了一种用于分析从成像板获得的海量数据的图像处理系统。该系统利用网络系统(ATES)，将东北大学材料加工研究所的计算机终端与东北大学计算机中心的超级计算机相连。利用该系统开发了考虑动态衍射效应的高分辨电子显微镜图像和电子衍射图分析软件，并将其应用于先进材料的高分辨电子显微镜图像分析。为了提高高分辨电子显微镜图像的计算机模拟精度，引入了氧化物薄膜的观测图像和模拟图像之间的剩余指数(R&lt；HREM&gt；)，并对其进行了评估。定量图像分析表明，可以定量地评价金属原子的部分占位情况，还可以检测到缺氧原子的位置。在电子衍射谱的分析中，开发了等离子体激发和声子激发的背景扣除软件，并将其应用于激光材料的结构分析。从电子衍射图的定量分析中发现，激光材料的晶体中有微小的原子位移。用电子能量损失谱研究了各种铜基化合物的电子结构，特别是费米能级附近的空态密度。

An image processing system for the analysis of huge data obtained from the imaging plate was developed. In the system, the network system (TAINS) was utilized and a computer terminal in Institute for Admanced Materials Processing was connected with a supercomputer in Computer Center, Tohoku University. With this system, the software of the analysis of high-resolution electron microscope (HREM) images and electron diffraction patterns was developed taking into account the dynamical diffraction effect and applied to HREM images of advanced materials. In order to obtain higher accuracy of computer simulation of HREM images, a residual index (R_<HREM>) between observed images and simulated images was introduced and evaluated for oxide thin films. From the quantitative image analysis, it was shown that partial occupancy of metal atoms could be quantitatively evaluated and deficient oxygen atom positions could be also detected. In the analysis of electron diffraction patterns, the software for subtracting the background, which was contributed from the plasmon excitation and phonon excitation, was developed and applied to the structure analysis of laser materials. From the quantitative analysis of the electron diffraction patterns, small atomic displacements in the crystal of the laser materials were detectd. Electron energy loss spectroscopy was also carried out to make clear the electronic structure, especially the unoccupied density of state near the Fermi level in various Cu based compounda.