Discommensurate Structure in [(Ca_<0.90>Sr_<0.10>)_2CoO_3]_<0.61>CoO_2(Condensed matter: structure and mechanical and thermal properties)

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著者

    • Yubuta Kunio YUBUTA Kunio
    • Institute for Materials Research, Tohoku University:Core Research for Evolutional Science and Technology, Japan Science and Technology Agency
    • Huang Xiangyang HUANG Xiangyang
    • Core Research for Evolutional Science and Technology, Japan Science and Technology Agency:Department of Applied Physics, Graduate School of Engineering, Tohoku University
    • Miyazaki Yuzuru [他] MIYAZAKI Yuzuru
    • Core Research for Evolutional Science and Technology, Japan Science and Technology Agency:Department of Applied Physics, Graduate School of Engineering, Tohoku University
    • KAJITANI Tsuyoshi
    • Core Research for Evolutional Science and Technology, Japan Science and Technology Agency:Department of Applied Physics, Graduate School of Engineering, Tohoku University

抄録

The crystal structure of partly Sr-substituted Co-121, i.e., "Ca_3Co_4Co_9", single crystal is studied by means of the electron diffraction measurements and high-resolution transmission electron microscopy (HREM). The crystal structure consists of two interpenetrating subsystems of a CoC_2 sheet and a distorted three-layered (Ca,Sr)_2CoO_3 rock-salt (RS)-type block layers, which belong to a triclinic system. Both subsystems have common a-, c-axes and α-, β-, γ-angle with a=4.8267(1)Å, c=10.9214(3)Å, α=90.916(2)°, β=98.291(5)°, and γ=89.957(3)°. On the other hand, the crystal structure is modulated parallel to the b-axis, along which the CoO_2 sheet has b_1=2.8346(1)Å and the (Ca,Sr)_2CoO_3 RS-type block layer has b_2=4.6391(2)Å, respectively. On the basis of the b_1/b_2 ratio and analyzed chemical compositions, the structure analogue is formulated as [(Ca_<0.90>Sr_<0.10>)_2CoO_3]_<0.61>CoO_2. In electron diffraction patterns, there are many new satellite reflections, namely 0101^^-, 0202^^-, 02^^-04, and 01^^-03, which are not present in the end member Co-121, i.e., (Ca_2CoO_3)_<0.620>CoO_2. Because of the new superlattice reflections, the crystal structure of the Sr-doped compound is different from the end member. HREM images were taken with the incident electron beam parallel to the [0010] and [1000] directions. The basic crystal structure of the present system consists of 5-CoO_2 and 3-RS subcells with b=14Å being connected discommensuratedly parallel to the a- and b-axes. Systematic introduction of stacking faults parallel to the a-b plane is also noticed.

収録刊行物

  • Journal of the Physical Society of Japan   [巻号一覧]

    Journal of the Physical Society of Japan 77(6), "064604-1"-"064604-5", 2008-06-15  [この号の目次]

    一般社団法人日本物理学会

参考文献:  23件

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各種コード

  • NII論文ID(NAID)
    10021030187
  • NII書誌ID(NCID)
    AA00704814
  • 本文言語コード
    ENG
  • 資料種別
    ART
  • ISSN
    00319015
  • NDL 記事登録ID
    9534267
  • NDL 雑誌分類
    ZM35(科学技術--物理学)
  • NDL 請求記号
    Z53-A404
  • データ提供元
    CJP書誌  NDL  NII-ELS  JPS 
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