Institute of Multidisciplinary Research for Advanced Materials, Tohoku University


LAST UPDATE 2021/05/06

  • 研究者氏名
    Researcher Name

    森川大輔 Daisuke MORIKAWA
    助教 Assistant Professor
  • 所属
    Professional Affiliation

    Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

    計測研究部門 電子回析・分光計測研究分野
    Division of Measurements, Electron-Crystallography and-Spectroscopy
  • 研究キーワード
    Research Keywords

    Transmission electron microscopy
    Convergent-beam electron diffraction
    Crystal structure analysis
Research Subject
Crystal and magnetic structure analysis using electron diffraction

研究の背景 Background


Transmission electron microscopy (TEM) is a powerful tool for an analysis in nano-scale specimen areas. Electron diffraction using a TEM is not almost affected by aberrations come from lens system. Thus, it is possible to achieve higher resolution than conventional imaging techniques. Especially, convergent-beam electron diffraction (CBED) can determine almost all crystal space group uniquely using dynamical scattering effect. CBED can be also used for a determination of electrostatic potential which is sensitive for slight deviation on electron density and bonding state at valence electrons.

研究の目標 Outcome


By using a combination with microscopy in TEM, we develop an accurate crystal structure analysis method for nano-scale specimen area. This may be a very powerful and useful technique for analysis in interfaces of crystal and grain boundaries. We also try a 2 dimensional mapping of crystal information with using machine-learning and simultaneous analysis on magnetic structures.

研究図Research Figure

Fig.1. Electrostatic potential determined by convergent-beam electron diffraction. (a) 4 e/Å3 isosurface of FeO4 tetrahedron of room-temperature cubic phase colored with electrostatic potential and (b) that of low-temperature tetragonal phase. (c) Schematic and (d) 4 e/Å3 isosurface of hypothetical Fe 3z2−r2 orbital-ordered model. [1] Fig.2. Convergent-beam electron diffraction (CBED) patterns of SmBa2O6 at 190 K (a) [001] incidence, (b) [100] incidence. The whole pattern symmetries are (a) m and (b) 2mm, respectively. From the symmetries of CBED patterns, the space group can be determined. [2]

文献 / Publications

[1] K. Tsuda, D. Morikawa et al, Phys. Rev. B 81, 180102(R) (2010). [2] D. Morikawa et al, J. Phys. Soc. Jpn. 81, 093602 (2012).