中国物理B ›› 2004, Vol. 13 ›› Issue (8): 1226-1229.doi: 10.1088/1009-1963/13/8/008

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Basic properties of an rf SQUID involving two Josephson junctions connected in series

毛博, 谭忠魁, 孟树超, 戴远东, 王福仁   

  1. State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
  • 收稿日期:2004-01-31 修回日期:2004-02-27 出版日期:2004-06-21 发布日期:2005-06-21
  • 基金资助:
    Project supported by the National Hi-Tech Development Programme of China (Grant No 2002AA306412) and the State Key Development Programme for Basic Research of China (Grant No G1999064609).

Basic properties of an rf SQUID involving two Josephson junctions connected in series

Mao Bo (毛博), Tan Zhong-Kui (谭忠魁), Meng Shu-Chao (孟树超), Dai Yuan-Dong (戴远东), Wang Fu-Ren (王福仁)   

  1. State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
  • Received:2004-01-31 Revised:2004-02-27 Online:2004-06-21 Published:2005-06-21
  • Supported by:
    Project supported by the National Hi-Tech Development Programme of China (Grant No 2002AA306412) and the State Key Development Programme for Basic Research of China (Grant No G1999064609).

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摘要： We have studied the basic characteristics of a radio frequency superconducting quantum interference device (rf SQUID) involving two Josephson junctions connected in series, the case for the widely used grain boundary junction (GBJ) rf SQUID. It is found that the SQUID properties are determined mainly by the weaker junction when the critical current of the weaker junction is much lower than that of the other junction. Otherwise, the effect of the other junction is not negligible. We also find that only when the hysteresis parameter β is less than 1-α, where α is the critical current ratio of the two junctions, will the SQUID operate in the nonhysteretic mode.

关键词: rf SQUID, grain boundary junction, hysteretic and nonhysteretic modes

Abstract: We have studied the basic characteristics of a radio frequency superconducting quantum interference device (rf SQUID) involving two Josephson junctions connected in series, the case for the widely used grain boundary junction (GBJ) rf SQUID. It is found that the SQUID properties are determined mainly by the weaker junction when the critical current of the weaker junction is much lower than that of the other junction. Otherwise, the effect of the other junction is not negligible. We also find that only when the hysteresis parameter $\beta$ is less than $1-\alpha$, where $\alpha$ is the critical current ratio of the two junctions, will the SQUID operate in the nonhysteretic mode.

Key words: rf SQUID, grain boundary junction, hysteretic and nonhysteretic modes

中图分类号:  (Superconducting quantum interference devices (SQUIDs))

  • 85.25.Dq
85.25.Cp (Josephson devices) 74.50.+r (Tunneling phenomena; Josephson effects) 74.25.Sv (Critical currents)