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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/987654321/25236

    題名: Structural phase transitions and the effect on Pr anomalous ordering for the PrBa2−xLaxCu3O7+y system
    作者: Ku, H. C.;Luo, H. M.;Chi, Y. P.;Lin, B. N.;Hsu, Y. Y.;Lin, C. H.;Kao, H. -C. I.
    貢獻者: 淡江大學化學學系
    關鍵詞: p–f hybridization;Anomalous ordering;Structural phase transition
    日期: 2000-06
    上傳時間: 2013-07-09 15:27:31 (UTC+8)
    出版者: Amsterdam: Elsevier BV * North-Holland
    摘要: Complex crystal symmetry variation is observed for the oxygenated PrBa2−xLaxCu3O7+y system (0⩽x⩽1, −0.12⩽y⩽0.39). Powder X-ray Rietveld analysis indicates that the crystal structure changes from the PrBa2Cu3O7 or CuBa2PrCu2O7 1212C-type (C for chain) orthorhombic O(I)-phase (space group Pmmm) to 1212-type tetragonal T-phase (P4/mmm) around x=0.45, and then to a new 1212-type of orthorhombic O(II)-phase (Cmmm) around x=0.65. However, regardless of the structural change, anomalous Pr ordering temperature TN(Pr) decreases monotonically from 18 K for PrBa2Cu3O6.88 to 2.8 K for PrBa1.3La0.7Cu3O7.24. The increasing Pr–O bond length with decreasing TN indicates that Pr ordering is closely correlated with the wave function overlap between Pr–4f orbital and O–2pπ orbital in the CuO2 bi-layers.
    關聯: Physica B: Condensed Matter 281-282, pp.892-893
    DOI: 10.1016/S0921-4526(99)00784-X
    顯示於類別:[化學學系暨研究所] 期刊論文


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