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2000 Fiscal Year Final Research Report Summary

PRECISE CRYSTAL STRUCURE DETERMINATION USING ELECTRON DIFRACTION PATTERNS RECORDED BY IMAGING PLATES

Research Project

Project/Area Number 11650035
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field 表面界面物性
Research InstitutionOKYAMA UNIVERSITY OF SCIENCE

Principal Investigator

YOKOTA Yasuhiro  OKAYAMA UNIV.OF SCI., NATURAL RESEARCH INSTI., PROFESSOR, 自然科学研究所, 教授 (50200902)

Project Period (FY) 1999 – 2000
Keywordselectron diffraction / imaging plate / chalogenide / phase transition / super structure / manganese oxides / tunnel structure / hydrothermal / resistivity
Research Abstract

The imaging plates (IP) were used for recording electron diffraction patterns of layered transition metal chalcogenides and manganeis oxides with tunnel structure. A ternary chalcogenide, α-BaCu_4S_3, shows a structural phase transition at 188-205K.The electron diffraction patterns were recorded both room temperature phase and low temperature phase. The crystallographic description of room temperature phase was orthorombic with the space group of Pnma. Upon cooling, the copper atoms in the channels start to modified. Electron diffraction studies revealed that the phase transition was accompanied by the formation of the superstructure with a wave vector of q = 1/5b^*. The observed superlattice electron diffraction patterns were analyzed on the basis of superstrucure model using multi-slice calculation method. The diffraction patterns were well explained by the simulation patterns.
Tunnel and layered manganese oxides constitute a large family of porous materials. Alk-Mn_<24>O_<48> (alk-RUB-7, alk=Rb, K) with 2 x 4 tunnel structure has been investigated using electron diffraction recorded with IP systems. Specimen manganese oxides were hydrothermally prepared. Temperature dependence of the resistivity of this material showed a small anomaly at 220K, indicating the presence of a phase transition. magnetic susceptibility obeyed a Curie-Weiss law above 77K.Also satellite spots were observed at ED patterns of the liquid nitrogen specimen temperature.
Further studies will be necessary to clarify fully the complex phase transition behavior of the present system.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] Q.Feng: "Synthesis of tunnel manganese oxides from layered manganese oxide by hydrothermal soft chemical process with Rb^+ as template."High Pressure Research. (印刷中). (2001)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Y.Okada: "Crystal structure of the low-temperature phase of Cu_<1.75>Se analyzed by electron diffraction"J.Electron Microsc.. 49. 25-29 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] T.Ohtani: "Charge Density Waves in Quasi-One-Dimensional Compound InxNb_3Te_4 (0<x<1.0) : Electron Diffraction Observations"Jpn.J.Appl.Phys.. 38. L142-L144 (1999)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 大谷槻男: "擬一次元カルコゲナイドの物性と相転移"金属. 70・7. 15-25 (2000)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] Q.Feng: "Synthesis of tunnel manganese oxides from layered manganese oxide by hydrothermal soft chemical process with Rb^+ as template"High Pressure Research. (in press). (2001)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y.Okada: "Crystal structure of the low-temperature phasre of βCu_<1.75>Se analysed by electron diffraction"J.Electron Microsc.. 49. 25-29 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Ohtani: "Charge Density Waves in Quasi-One-Dimensional Compound In_xNb_3Te_4 (0 < x < 1.0) : Electron Diffraction Observations"Jpn.J.Appl.Phys.. 38. L142-L144 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] T.Ohtani: "Physical properties and phase transition of pseudo-one-dimensional Chalogenides (Japanese)"Kinzoku. 70-7. 15-25 (2000)

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 2002-03-26  

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