中国物理B ›› 2007, Vol. 16 ›› Issue (10): 3036-3041.doi: 10.1088/1009-1963/16/10/036

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A study on the microwave responses of YBCO and TBCCO thin films by coplanar resonator technique

王云飞1, 柯于洋1, 张国华1, 罗 胜1, 张雪强1, 史力斌2, 李春光3, 黎 红3, 何豫生3   

  1. (1)Department of Physics, University of Science and Technology Beijing, Beijing 100083, China; (2)Department of Physics, University of Science and Technology Beijing, Beijing 100083, China;Department of Physics, Bohai University, Jinzhou 121000, China; (3)Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
  • 收稿日期:2006-12-05 修回日期:2007-04-11 出版日期:2007-10-08 发布日期:2007-10-08
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 10474121).

A study on the microwave responses of YBCO and TBCCO thin films by coplanar resonator technique

Shi Li-Bin(史力斌)a)b), Wang Yun-Fei(王云飞)a), Ke Yu-Yang(柯于洋)a), Zhang Guo-Hua(张国华)a), Luo Sheng(罗胜)a)†, Zhang Xue-Qiang(张雪强)c), Li Chun-Guang(李春光)c), Li Hong(黎红)c), and He Yu-Sheng(何豫生) c)   

  1. a Department of Physics, University of Science and Technology Beijing, Beijing 100083, China; b Department of Physics, Bohai University, Jinzhou 121000, China; c Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China
  • Received:2006-12-05 Revised:2007-04-11 Online:2007-10-08 Published:2007-10-08
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 10474121).

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摘要： YBa2Cu3O7(YBCO) thin films have been prepared by thermal coevaporation on LaAlO3(LAO) substrates, and Tl2Ba2CaCu2O8(TBCCO) thin films are synthesized by magnetron sputtering method on LAO substrates. The transition temperature Tc is 90\,K for YBCO/LAO and 104\,K for TBCCO/LAO. Microwave responses of the films are studied systematically by coplanar resonator technique. Energy gaps of the films obtained are {\it\Delta}0=1.04kBTc for YBCO films and ${\it\Delta}_0=0.84kBTc for TBCCO films by analysing the temperature dependence of resonant frequencies of coplanar resonator. Penetration depth at 0\,K \lambda 0=198nm for YBCO films and \lambda0 =200nm for TBCCO films could also be obtained by using the weak coupling theory and two fluid theory. Results of penetration depth and energy gap confirm the weak coupling properties of the films. In addition, microwave surface resistances Rs of YBCO/LAO and TBCCO/LAO are also investigated by analysing the quality factor and insert loss of the coplanar resonator. Surface resistance of TBCCO/LAO is less than that of YBCO/LAO, so that TBCCO/LAO films may have more potential applications.

关键词: YBCO, TBCCO, superconducting films, coplanar resonator

Abstract: YBa2Cu3O7(YBCO) thin films have been prepared by thermal coevaporation on LaAlO3(LAO) substrates, and Tl2Ba2CaCu2O8(TBCCO) thin films are synthesized by magnetron sputtering method on LAO substrates. The transition temperature Tc is 90 K for YBCO/LAO and 104 K for TBCCO/LAO. Microwave responses of the films are studied systematically by coplanar resonator technique. Energy gaps of the films obtained are ${\it\Delta}_0=1.04k_{\rm B}T_{\rm c} $ for YBCO films and ${\it\Delta}_0=0.84k_{\rm B}T_{\rm c} $ for TBCCO films by analysing the temperature dependence of resonant frequencies of coplanar resonator. Penetration depth at 0 K $\lambda _0 =198$ nm for YBCO films and $\lambda _0 =200$ nm for TBCCO films could also be obtained by using the weak coupling theory and two fluid theory. Results of penetration depth and energy gap confirm the weak coupling properties of the films. In addition, microwave surface resistances Rs of YBCO/LAO and TBCCO/LAO are also investigated by analysing the quality factor and insert loss of the coplanar resonator. Surface resistance of TBCCO/LAO is less than that of YBCO/LAO, so that TBCCO/LAO films may have more potential applications.

Key words: YBCO, TBCCO, superconducting films, coplanar resonator

中图分类号: 

  • 74.25.Nf
74.25.Ha (Magnetic properties including vortex structures and related phenomena) 74.25.Jb (Electronic structure (photoemission, etc.))