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    請使用永久網址來引用或連結此文件: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/25124

    題名: Oxygen nonstoichiometry, structural phase transitions and anomalous Pr ordering for PrBa2-xLaxCu3Oz solid solution
    作者: Luo, H. M.;Ding, S. Y.;Lu, G. X.;Lin, B. N.;Ku, H. C.;Lin, C. H.;高惠春;Kao, H. C. I.;Ho, J. C.
    貢獻者: 淡江大學化學學系
    日期: 2001-06
    上傳時間: 2009-12-01
    出版者: Institute of Physics (IOP)
    摘要: The oxygen nonstoichiometry, structure, magnetic and calorimetric data for La doped Ba-site PrBa2-xLaxCu3Oz systems (0≤x≤1 and 6.881≤z≤ 7392) are reported. The x-dependence of the oxygen content increases monotonically and two structural phase transitions are observed, confirmed by powder x-ray Rietveld analysis, from the orthorhombic 1212C-phase (space group: Pmmm) to tetragonal 1212 (P4/mmm) at x = 0.45, and then to another orthorhombic (Cmmm) phase around x = 0.7. Magnetic susceptibility and heat capacity measurements show that the anomalous Néel temperature TN(Pr) decreases monotonically from 18 K for x = 0 to 2.8 K for PrBa1.3La0.7Cu3O7.236 and to below 2 K for x≥0.8 for samples prepared under the same conditions, while TN(Pr) increases with an increase of oxygen content for the same compound. The increasing Pr-O bond length observed with decreasing TN(Pr) indicates that this unusual Pr magnetic ordering is closely related to the wave-function overlap between the Pr-4f orbital and eight O-2pπ orbital in the CuO2 bi-layer. No superconductivity has been detected for these insulating cuprates.
    關聯: Superconductor Science and Technology 14(6), pp.320-325
    DOI: 10.1088/0953-2048/14/6/305
    顯示於類別:[化學學系暨研究所] 期刊論文


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