›› 2014, Vol. 23 ›› Issue (9): 97401-097401.doi: 10.1088/1674-1056/23/9/097401

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Fabrication and properties of high performance YBa2Cu3O7-δ radio frequency SQUIDs with step-edge Josephson junctions

刘政豪, 魏玉科, 王达, 张琛, 马平, 王越   

  1. Applied Superconductivity Research Center, State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
  • 收稿日期:2013-12-25 修回日期:2014-04-08 出版日期:2014-09-15 发布日期:2014-09-15
  • 基金资助:
    Project supported by the National Basic Research Program of China (Grant No. 2011CBA00106), the National Natural Science Foundation of China (Grant No. 11074008), and the Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20100001120006).

Fabrication and properties of high performance YBa2Cu3O7-δ radio frequency SQUIDs with step-edge Josephson junctions

Liu Zheng-Hao (刘政豪), Wei Yu-Ke (魏玉科), Wang Da (王达), Zhang Chen (张琛), Ma Ping (马平), Wang Yue (王越)   

  1. Applied Superconductivity Research Center, State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
  • Received:2013-12-25 Revised:2014-04-08 Online:2014-09-15 Published:2014-09-15
  • Contact: Ma Ping E-mail:maping@pku.edu.cn
  • Supported by:
    Project supported by the National Basic Research Program of China (Grant No. 2011CBA00106), the National Natural Science Foundation of China (Grant No. 11074008), and the Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20100001120006).

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摘要： We describe the fabrication of high performance YBa2Cu3O7-δ (YBCO) radio frequency (RF) superconducting quantum interference devices (SQUIDs), which were prepared on 5 mm×5 mm LaAlO3 (LAO) substrates by employing step-edge junctions (SEJs) and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47° to 61°, which is steep enough to ensure the formation of grain boundaries (GBs) at the step edges. The YBCO film was deposited using the pulsed laser deposition (PLD) technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH. Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/Φ 0, a white flux noise of 29 μΦ 0/√Hz, and the magnetic field sensitivity as high as 80 fT/√Hz. These devices have been applied in magnetocardiography and geological surveys.

关键词: superconducting quantum interference device (SQUID), YBa2Cu3O7-δ (YBCO), step-edge junction, radio frequency

Abstract: We describe the fabrication of high performance YBa2Cu3O7-δ (YBCO) radio frequency (RF) superconducting quantum interference devices (SQUIDs), which were prepared on 5 mm×5 mm LaAlO3 (LAO) substrates by employing step-edge junctions (SEJs) and in flip-chip configuration with 12 mm×12 mm resonators. The step in the substrate was produced by Ar ion etching with step angles ranging from 47° to 61°, which is steep enough to ensure the formation of grain boundaries (GBs) at the step edges. The YBCO film was deposited using the pulsed laser deposition (PLD) technique with a film thickness half of the height of the substrate step. The inductance of the SQUID washer was designed to be about 157 pH. Under these circumstances, high performance YBCO RF SQUIDs were successfully fabricated with a typical flux-voltage transfer ratio of 83 mV/Φ 0, a white flux noise of 29 μΦ 0/√Hz, and the magnetic field sensitivity as high as 80 fT/√Hz. These devices have been applied in magnetocardiography and geological surveys.

Key words: superconducting quantum interference device (SQUID), YBa2Cu3O7-δ (YBCO), step-edge junction, radio frequency

中图分类号:  (Cuprate superconductors)

  • 74.72.-h
68.37.Ps (Atomic force microscopy (AFM)) 74.78.-w (Superconducting films and low-dimensional structures) 85.25.Dq (Superconducting quantum interference devices (SQUIDs))