放射光を利用した正方晶系チタン酸バリウムのサブミクロン結晶の軸率c/aの決定

概要

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The tetragonality of submicrometer sized crystals of barium titanate, BaTiO_3, has been investigated by the ultramicro single crystal X ray diffraction technique using synchrotron radiation. The c/a ratios have been determined using the splitting of Laue spots due to twinning to be 1.0072 (2) and 1.0106(6) for crystals with conversion diameters of 0.56μm and 10μm respectively. The c/a ratio of the 10μm crystal is approximately the same as that of the bulk crystal, while it is significantly small for the 0.56 μm crystal, indicating that the size effect on the tetragonal to cubic phase transition is remarkable in the Submicrometer region. No clear splitting due to tetragonal twinning was observed for the crystal with a conversion diameter of 0.25 μm, suggesting that the critical size for the transition is close to this size.
社団法人日本セラミックス協会の論文
1994-02-01