物理化学学报 >> 1995, Vol. 11 >> Issue (03): 228-233.doi: 10.3866/PKU.WHXB19950309

研究论文 上一篇    下一篇

n型T'-214相超导体的结构和性质

张玉芬, 林勤   

  1. 北京大学化学系|物理系|北京 100871
  • 收稿日期:1994-02-23 修回日期:1994-05-16 发布日期:1995-03-15
  • 通讯作者: 张玉芬

Structure and Properties on n-Type T'-214 Phase Superconductors

Zhang Yu-Fen, Lin Qin   

  1. Department of Chemsitry,Peking University,Beijing 100871|Department of Physics,Peking University
  • Received:1994-02-23 Revised:1994-05-16 Published:1995-03-15
  • Contact: Zhang Yu-Fen

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摘要：

T＇－214相化合物R2-xCexCuO4（R为稀土离子）成为超导体决定于R3+的离子半径大小、Ce4+的取代量和化合物的热处理时的稳定性．从Raman光谱实验结果提出热处理过程中发生电荷转移．Ce4+的取代引起TN（Cu）下降，当TN（Cu）降到0时，超导性出现。不同的稀土离子TN（Cu）不同，稀土离子的反铁磁性（AFM）与超导性（SC）共存。热电势的测量结果可以用双通道模型解释，n型超导体中电子与空穴共存．

关键词: 电子型超导体, 磁有序, 比热, 热电势, 拉曼光谱

Abstract:

Electron-doped T’-R2CuO4 type superconductors have been studied by X-ray diffraction, neutron diffraction, Raman, XPS, FT-IR, XAS, inelastic neutron sacttering, AC and DC magnetic measurement, resistivity measurement, specific heat and TEP measurement. A model was proposed from these experements. When R3+ was substituted with Ce4+ in the parent insulator R2CuO4, a part of doped electrons entered into CuO2 plane, but the other part was localized in the vicinity of Nd (Ce) ions. AFM ordering temperature of Cu disappeares as the dopant concentration approaches that required for superconductivity (Ce=0.15). After annealing treatment in N2 atmosphere, the localized electrons in the vicinity of Nd (Ce) ions transfered to the CuO2 plane and became free elections, the concentration of charge carriers was large enough to create SC. Some questions are still not clear at the present. It is necessary to perform more experements.

Key words: Electron-doped Superconductors, Magnetic order, Specific heat, Thermoelectric power, Raman spectra