Progress in High Tc Superconducting Quantum Interference Device (SQUID) Magnetometer

Keiji ENPUKU  Tadashi MINOTANI  

IEICE TRANSACTIONS on Electronics   Vol.E83-C   No.1   pp.34-43
Publication Date: 2000/01/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: INVITED PAPER (Special Issue on Superconductive Devices and Systems)
Category: SQUIDs
high Tc SQUID,  magnetometer,  gradiometer,  noise,  bicrystal junction,  

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Recent progresses in high Tc superconducting quantum interference device (SQUID) magnetometers are discussed. First, intrinsic sensitivity of the SQUID at T=77 K is discussed. For this purpose, transport and noise properties of the bicrystal junction are clarified, and optimization of junction parameters is shown. We also discuss the quality of the SQUID from a comprehensive comparison between experiment and simulation of the SQUID characteristics. Next, we discuss issues to guarantee correct operation of the SQUID magnetometer in noisy environment, such as a method to avoid flux trapping due to earth magnetic field, high-bandwidth electronics and gradiometer. Finally, we briefly describe application fields of the high Tc magnetometer.