Quantitative analysis of materials by new electron microscopy technique

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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.