Direct observations of Ca ordering in Ca0.33 CoO2 thin films with different superstructures

Rong Huang, Teruyasu Mizoguchi, Kenji Sugiura, Hiromichi Ohta, Kunihito Koumoto, Tsukasa Hirayama, Yuichi Ikuhara

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    9 Citations (Scopus)


    Ca-ion superstructures such as 3a×3a (hexagonal) and 2a×3a (orthorhombic) in layered Ca0.33 CoO2 crystalline film, which were prepared by the reactive solid-phase epitaxy and the subsequent ion-exchange treatment, were directly distinguished by using spherical-aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The fluctuation of Ca intensities in the HAADF-STEM image indicates the existence of many Ca vacancies in the 2a×3a orthorhombic superstructure, which is consistent with the partial occupation of Ca (x=0.33) in the cation sites of x=0.5.

    Original languageEnglish
    Article number181907
    JournalApplied Physics Letters
    Issue number18
    Publication statusPublished - 2008

    ASJC Scopus subject areas

    • Physics and Astronomy (miscellaneous)

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