Observation of local crystal structure change in (CaxLa1-x)(Ba1.75-xLa0.25+x) Cu3O7+δ tetragonal superconductor using Raman scattering

被引:0
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作者
Sato, Yasushi [1 ]
Yoshioka, Kohtaro [1 ]
Petrykin, Valery [1 ]
Kakihana, Masato [1 ]
Tanaka, Yoshito [1 ]
Yamaguchi, Ai [1 ]
Katsumata, Takahiro [1 ]
Yasuoka, Hiroshi [1 ]
机构
[1] Materials and Structures Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta Midori-ku, Yokohama 226-8503, Japan
关键词
Crystal defects - Crystal structure - Crystal symmetry - High temperature superconductors - Mathematical models - Molecular vibrations - Polycrystalline materials - Raman scattering - Yttrium barium copper oxides;
D O I
10.2497/jjspm.49.372
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摘要
Polycrystalline samples of (CaxLa1-x)(Ba1.75-xLa0.25+x)Cu3 O7+δ (CLBCO) tetragonal superconductor for x from 0.0 to 0.6 were studied by Raman scattering technique, which is sensitive to oxygen site symmetry in the high-Tc superconductors. On the Raman spectra, five extra modes at 200, 320, 400, 565 and 610 cm-1, which did not appear on Raman spectra of tetragonal YBa2Cu3O6, were observed. Based on the model that apical oxygen O(4) is displaced by La3+ on Ba site and the result of group theoretical analysis for this model, the 565 cm-1 mode which possessed the strongest intensity among these extra modes could be assigned to another O(4) vibration. This indicates that O(4) is strongly attracted by La3+ on Ba site, resulting in a change of local structure.
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页码:372 / 376
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