中国物理B ›› 1999, Vol. 8 ›› Issue (9): 702-710.doi: 10.1088/1004-423X/8/9/010

• • 上一篇    

PHASE SEPARATION AND JOSEPHSON-COUPLING ORIGIN FOR THE ANOMALOUS Hc2 BEHAVIOR IN OVERDOPED Bi2Sr2-xLaxCuO6+δ CRYSTALS

杨万里, 闻海虎, 倪泳明, 赵忠贤   

  1. State Key Laboratory of Superconductivity, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China
  • 收稿日期:1999-04-04 出版日期:1999-09-15 发布日期:1999-09-20
  • 基金资助:
    Project supported by the National Natural Science Foundatoin of China (Grant No. 19825111).

PHASE SEPARATION AND JOSEPHSON-COUPLING ORIGIN FOR THE ANOMALOUS Hc2 BEHAVIOR IN OVERDOPED Bi2Sr2-xLaxCuO6+$\delta$ CRYSTALS

Yang Wan-li (杨万里), Wen Hai-hu (闻海虎), Ni Yong-ming (倪泳明), Zhao Zhong-xian (赵忠贤)   

  1. State Key Laboratory of Superconductivity, Institute of Physics and Center for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China
  • Received:1999-04-04 Online:1999-09-15 Published:1999-09-20
  • Supported by:
    Project supported by the National Natural Science Foundatoin of China (Grant No. 19825111).

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摘要： Hole-overdoped Bi2Sr2-xLaxCuO6+$\delta$ single crystals with two coexistent superconducting transitions have been intensively studied by measuring the dc magnetic susceptibility. It is found that the coexistence of these two phases cannot be attributed to any chemical or vortex dynamical effect but to some intrinsic driving force, such as the electronic-driven phase separation. Furthermore, the upper critical fields of the two phases behave in a rather different way; that is, one of them shows a "normal Hc2 behavior" which can be described by the critical fluctuation theory, while the other exhibits an "anomalous Hc2 behavior" and can be well explained by a recent theory based on an assumption of a Josephson-coupling origin, indicating a strong evidence of Josephson-coupling origin for the upward curvature of the so-called Hc2 in high Tc superconductors.

Abstract: Hole-overdoped Bi2Sr2-xLaxCuO6+$\delta$ single crystals with two coexistent superconducting transitions have been intensively studied by measuring the dc magnetic susceptibility. It is found that the coexistence of these two phases cannot be attributed to any chemical or vortex dynamical effect but to some intrinsic driving force, such as the electronic-driven phase separation. Furthermore, the upper critical fields of the two phases behave in a rather different way; that is, one of them shows a "normal Hc2 behavior" which can be described by the critical fluctuation theory, while the other exhibits an "anomalous Hc2 behavior" and can be well explained by a recent theory based on an assumption of a Josephson-coupling origin, indicating a strong evidence of Josephson-coupling origin for the upward curvature of the so-called Hc2 in high Tc superconductors.

中图分类号:  (Tunneling phenomena; Josephson effects)

  • 74.50.+r
75.30.Cr (Saturation moments and magnetic susceptibilities) 74.25.Ha (Magnetic properties including vortex structures and related phenomena) 74.25.Op (Mixed states, critical fields, and surface sheaths)