中国物理B ›› 2008, Vol. 17 ›› Issue (4): 1425-1429.doi: 10.1088/1674-1056/17/4/046

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Effect of heat treatment on electronic phase in underdoped La2-xSrxCuO4 single crystal

申彩霞, 慎晓丽, 陆伟, 董晓莉, 李正才, 熊季午, 周放   

  1. National Laboratory for Superconductivity, Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China
  • 收稿日期:2007-11-16 修回日期:2007-12-18 出版日期:2008-04-20 发布日期:2008-04-20
  • 基金资助:
    Project supported by the Ministry of Science and Technology of China (973 project Grant No 2006CB0L0302), the National Natural Science Foundation of China (Grant No 10574149) and Chinese Academy of Sciences (Grant No KJCX2-SW-W18).

Effect of heat treatment on electronic phase in underdoped La2-xSrxCuO4 single crystal

Shen Cai-Xia(申彩霞), Shen Xiao-Li(慎晓丽), Lu Wei(陆伟), Dong Xiao-Li(董晓莉), Li Zheng-Cai(李正才), Xiong Ji-Wu(熊季午), and Zhou Fang(周放)†   

  1. National Laboratory for Superconductivity, Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, China
  • Received:2007-11-16 Revised:2007-12-18 Online:2008-04-20 Published:2008-04-20
  • Supported by:
    Project supported by the Ministry of Science and Technology of China (973 project Grant No 2006CB0L0302), the National Natural Science Foundation of China (Grant No 10574149) and Chinese Academy of Sciences (Grant No KJCX2-SW-W18).

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摘要： Superconducting La2-xSrxCuO4 crystals grown by the travelling-solvent floating-zone technique were thermally treated under various temperatures and oxygen pressures for moderately adjusting the oxygen content. The response of intrinsic electronic property of the crystals to the change of hole density in La2-xSrxCuO4 in the vicinity of the magic doping of x =1/16\ (=0.0625) is studied in detail by magnetic measurements under various fields up to 1\,T. It is found that when the superconducting critical temperature (T_{\rm C}) increases with the oxygen content, there appears also a new subtle electronic state that can be detected from the differential curves of diamagnetic susceptibility d$\chi$/d$T$ of the crystal sample. In contrast with the intrinsic state, the new subtle electronic state is very fragile under the magnetic fields. Our results indicate that a moderate change in oxygen doping does not significantly modify the intrinsic electronic state originally existing at the magic doping level.

关键词: La2-xSrxCuO4, single crystal, superconductive electronic phase

Abstract: Superconducting La2-xSrxCuO4 crystals grown by the travelling-solvent floating-zone technique were thermally treated under various temperatures and oxygen pressures for moderately adjusting the oxygen content. The response of intrinsic electronic property of the crystals to the change of hole density in La2-xSrxCuO4 in the vicinity of the magic doping of x =1/16  (=0.0625) is studied in detail by magnetic measurements under various fields up to 1 T. It is found that when the superconducting critical temperature ($T_{\rm C}$) increases with the oxygen content, there appears also a new subtle electronic state that can be detected from the differential curves of diamagnetic susceptibility d$\chi$/d$T$ of the crystal sample. In contrast with the intrinsic state, the new subtle electronic state is very fragile under the magnetic fields. Our results indicate that a moderate change in oxygen doping does not significantly modify the intrinsic electronic state originally existing at the magic doping level.

Key words: La2-xSrxCuO4, single crystal, superconductive electronic phase

中图分类号: 

  • 74.25.Fy
74.25.Ha (Magnetic properties including vortex structures and related phenomena) 74.25.Jb (Electronic structure (photoemission, etc.)) 74.62.Dh (Effects of crystal defects, doping and substitution)