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    Please use this identifier to cite or link to this item: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/25273

    Title: Superconductivity in the triple-perovskite La-Ca-Ba-Cu-O system
    Other Titles: 具三層鈦酸鈣結構的La-Ca-Ba-Cu-O系統的超導性
    Authors: Yang, Y. F.;Wu, D. S.;Kao, H. C. I.;高惠春;Wang, C. M.;王啓銘
    Contributors: 淡江大學化學學系
    Date: 1995-12-01
    Issue Date: 2009-12-01
    Publisher: Institute of Physics (IOP)
    Abstract: Three series of single-phase La-Ca-Ba-Cu-O compounds with tetragonal triple-perovskite structure and respective nominal compositions of La4-xCaxBa3Cu7Oy (LC series, 0.50<or=x<or=1.15), La3CaxBa4-xCu7Oy (CB series, 0<or=x<or=1.25) and La3.5-0.5xCaxBa3.5-0.5xCu7Oy (LCB series, 0<or=x<or=1.25) were prepared by either a solid state reaction method or a polymeric citrate precursor method. All the single-phase materials were superconducting except for samples containing small x in the LCB series. Unit-cell parameters, such as a axes, c axes and cell volume, decreased with increasing Ca substitution. In general, the Tc and hole concentration (p) increased with increasing x from x=0 to x=1.00. In other words, evidence of hole doping was observed during Ca substitution that was the main reason for the increase of the Tc from 0 to 80 K. The optimal Tc was observed in a region close to the formula of La3CaBa3Cu7Oy which had a formula per unit celt of La1.29Ca0.43Ba1.29Cu3Oz where z=7.104, p=0.308, a axis =0.3879 nm and Tc(zero)=80 K.
    Relation: Superconductor Science and Technology 8(12), pp.874-878
    DOI: 10.1088/0953-2048/8/12/004
    Appears in Collections:[化學工程與材料工程學系暨研究所] 期刊論文
    [化學學系暨研究所] 期刊論文

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