中国物理B ›› 2005, Vol. 14 ›› Issue (2): 301-305.doi: 10.1088/1009-1963/14/2/014

• GENERAL • 上一篇    下一篇

Intrinsic flux noise level of an rf SQUID involving two Josephson junctions connected in series

毛博, 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:2004-07-12 修回日期:2004-08-09 出版日期:2005-03-02 发布日期:2005-03-02
  • 基金资助:
    Project supported by the Hi-Tech Research and Development Programme of China (Grant No 2002AA306412) and the Key Basic Research and Development Programme of China (Grant No G1999064609).

Intrinsic flux noise level of an rf SQUID involving two Josephson junctions connected in series

Mao Bo (毛博), 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:2004-07-12 Revised:2004-08-09 Online:2005-03-02 Published:2005-03-02
  • Supported by:
    Project supported by the Hi-Tech Research and Development Programme of China (Grant No 2002AA306412) and the Key Basic Research and Development Programme of China (Grant No G1999064609).

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摘要： The time-dependent characteristics of a radio frequency superconducting quantum interference device (rf SQUID) involving two Josephson junctions connected in series are studied. First the dynamics of the total flux is given. Then the intrinsic flux noises in both nonhysteretic and hysteretic modes are investigated. The result shows that it is necessary to properly reduce the critical current ratio of the two junctions for low intrinsic noise level. When the critical current ratio is properly reduced, the intrinsic flux noise level of a two-junction rf SQUID is generally close to or slightly larger than that of a single junction rf SQUID, but no more than one order-of-magnitude.

Abstract: The time-dependent characteristics of a radio frequency superconducting quantum interference device (rf SQUID) involving two Josephson junctions connected in series are studied. First the dynamics of the total flux is given. Then the intrinsic flux noises in both nonhysteretic and hysteretic modes are investigated. The result shows that it is necessary to properly reduce the critical current ratio of the two junctions for low intrinsic noise level. When the critical current ratio is properly reduced, the intrinsic flux noise level of a two-junction rf SQUID is generally close to or slightly larger than that of a single junction rf SQUID, but no more than one order-of-magnitude.

Key words: rf SQUID, RCSJ model, intrinsic flux noise, hysteretic and nonhysteretic modes

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

  • 85.25.Dq
74.25.Sv (Critical currents)