TY - JOUR
T1 - Low noise operation of a DC squid in a large β regime and its application to the design of a high TC squid
AU - Enpuku, K.
AU - Kohjiro, S.
AU - Yoshida, K.
N1 - Copyright:
Copyright 2015 Elsevier B.V., All rights reserved.
PY - 1989/3
Y1 - 1989/3
N2 - Noise characteristics of a large-β dc SQUID have been studied experimentally in the case when a SQUID inductance is resistively shunted. Here, ß=2LIo/¢o is a modulation parameter, L is a SQUID inductance, Io is a critical current and ¢o is the flux quantum. Energy resolutions of the SQUIDs, ε, have been measured for various β values up to β=19. It is shown experimentally that energy resolutions of the present large-β SQUIDs are as small as that of the conventional SQUID with β=1. For example, energy resolution ε=25h was obtained even for β=12(L=340pH and Io=37µA), where his the Planck constant. The obtained experimental results agree quantitatively with theoretical ones. It is also shown that the present resistively-shunted-inductance scheme is very useful in developing SQUIDs operating at T=77k with high-Tc superconductors, where the value of β will become necessarily large in order to avoid noise effects. Numerical simulations on the performance of the high-Tc SQUID are presented.
AB - Noise characteristics of a large-β dc SQUID have been studied experimentally in the case when a SQUID inductance is resistively shunted. Here, ß=2LIo/¢o is a modulation parameter, L is a SQUID inductance, Io is a critical current and ¢o is the flux quantum. Energy resolutions of the SQUIDs, ε, have been measured for various β values up to β=19. It is shown experimentally that energy resolutions of the present large-β SQUIDs are as small as that of the conventional SQUID with β=1. For example, energy resolution ε=25h was obtained even for β=12(L=340pH and Io=37µA), where his the Planck constant. The obtained experimental results agree quantitatively with theoretical ones. It is also shown that the present resistively-shunted-inductance scheme is very useful in developing SQUIDs operating at T=77k with high-Tc superconductors, where the value of β will become necessarily large in order to avoid noise effects. Numerical simulations on the performance of the high-Tc SQUID are presented.
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U2 - 10.1109/20.92494
DO - 10.1109/20.92494
M3 - Article
AN - SCOPUS:0024628276
SN - 0018-9464
VL - 25
SP - 1154
EP - 1157
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
IS - 2
ER -