中国物理B ›› 1993, Vol. 2 ›› Issue (9): 678-687.doi: 10.1088/1004-423X/2/9/006

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INFLUENCE OF OXYGEN UPON THE SUPERCONDUCTIVITY OF THE Pb-DOPED 2223 SUPERCONDUCTOR

陈廷国, 沈忠哲, 谢晓明, 陈源   

  1. Shanghai Institute of Metallurgy, Academia Sinica, Shanghai 200050, China
  • 收稿日期:1992-11-24 出版日期:1993-09-20 发布日期:1993-09-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China and the Chinese Center for Research and Development on Superconductivity.

INFLUENCE OF OXYGEN UPON THE SUPERCONDUCTIVITY OF THE Pb-DOPED 2223 SUPERCONDUCTOR

CHEN TING-GUO (陈廷国), SHEN ZNONG-ZHE (沈忠哲), XIE XIAO-MING (谢晓明), CHEN YUAN (陈源)   

  1. Shanghai Institute of Metallurgy, Academia Sinica, Shanghai 200050, China
  • Received:1992-11-24 Online:1993-09-20 Published:1993-09-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China and the Chinese Center for Research and Development on Superconductivity.

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摘要： The influences of oxygen content (by quenching from different temperatures in air or oxygen) and its re-distribution (by annealing in nitrogen at 200℃) on Tc and room temperature resistivity were studied. It was found that Tc as a function of oxygen content or charge carrier concentration exhibits a maximum. Upon oxygen re-distribution, the room temperature resistivity would always inclose but Tc would change in a complicated way. Tc increases for the oxygen-rich state and decreases for the oxygen-deficient state Internal friction measurements showed that there are two kinds of oxygen defects in the Bi2-O2 layers. One is the isolated oxygen interstitials and the other is oxygen vacancies on the excess oxygen chains. It is proposed that the isolated interstitial oxygen will produce a set of impurity states near the Fermi level, and will create holes on the Cu3d-O2p band through charge transfer from the Cu3d-O2p band to the impurity states. The content of the isolated oxygen interstitial is believed to be the major factor for determining the charge carrier concentration. Variation of Tc and room temperature resistivity with oxygen re-distribution is sat-isfactorily explained as to be induced by combination of oxygen interstitials with oxygen vacancies on the excess oxygen-chains.

Abstract: The influences of oxygen content (by quenching from different temperatures in air or oxygen) and its re-distribution (by annealing in nitrogen at 200℃) on Tc and room temperature resistivity were studied. It was found that Tc as a function of oxygen content or charge carrier concentration exhibits a maximum. Upon oxygen re-distribution, the room temperature resistivity would always inclose but Tc would change in a complicated way. Tc increases for the oxygen-rich state and decreases for the oxygen-deficient state Internal friction measurements showed that there are two kinds of oxygen defects in the Bi2-O2 layers. One is the isolated oxygen interstitials and the other is oxygen vacancies on the excess oxygen chains. It is proposed that the isolated interstitial oxygen will produce a set of impurity states near the Fermi level, and will create holes on the Cu3d-O2p band through charge transfer from the Cu3d-O2p band to the impurity states. The content of the isolated oxygen interstitial is believed to be the major factor for determining the charge carrier concentration. Variation of Tc and room temperature resistivity with oxygen re-distribution is sat-isfactorily explained as to be induced by combination of oxygen interstitials with oxygen vacancies on the excess oxygen-chains.

中图分类号:  (Effects of crystal defects, doping and substitution)

  • 74.62.Dh
74.25.Ld (Mechanical and acoustical properties, elasticity, and ultrasonic Attenuation) 71.55.Ht (Other nonmetals)