Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

IEICE Transactions on Electronics

Evaluation of High-Tc Superconducting Quantum Interference Device with Alternating Current Bias DOIT and Additional Positive Feedback

Akira Adachi

Published Oct 25, 1997• 0 citations
OpenAlex

Related papers

High-T_c Superconducting Quantum Interference Device with Additional Positive Feedback

Akira Adachi, Kenichi Okajima, Youichi Takada +4 more

IEICE Transactions on Electronics•May 25, 1995•1 citation

An ac Bias Readout Scheme for High Tc dc-Superconducting Quantum Interference Devices

Shinya Kuriki Shinya Kuriki, Daisuke Suzuki Daisuke Suzuki

We propose a readout scheme for high-T c dc-SQUIDs (superconducting quantum interference devices) with alternating current bias and synchronized offset flux. By use of this scheme, low-frequency noise due to critical current fluctuations, which exist in grain boundary junctions, can be canceled. The readout electronics are simple and operation parameters requiring adjustment are minimized. The ac bias scheme has been applied to YBCO step-junction SQUIDs, where partial reduction of the equivalent flux noise below 100 Hz is observed.

Japanese Journal of Applied Physics•Aug 1, 1993•5 citations

Simplified analysis of direct SQUID readout schemes

D. Drung

A simple approach to understanding and analyzing direct readout schemes for superconducting quantum interference devices (SQUIDs) is presented. It is shown that the existing methods for suppression of room temperature amplifier noise are based on voltage feedback and current feedback in the SQUID, that were introduced in the original schemes of additional positive feedback and bias current feedback. It is also shown that the way the SQUID is biased (at constant current or voltage) does not affect the noise suppression.

Superconductor Science and Technology•Apr 21, 2010•25 citations

Superconducting Quantum Interference Devices: An Operational Guide for Rf-Biased Systems

Donald B. Sullivan

•Oct 28, 2017•20 citations

Superconducting quantum interference devices with different damped junctions operated in directly coupled current- and voltage-bias modes

Jia Zeng, Yi Zhang, Yang Qiu +4 more

We investigate niobium thin film superconducting quantum interference devices (SQUIDs) with different Steward—McCumber parameters βc operated in both current- and voltage-bias modes. We experimentally prove that there is no difference between the two bias modes with respect to the SQUID intrinsic noise and the noise contribution from the preamplifier. Furthermore, the relationships of the SQUID dynamic parameters, (Rd)current bias ≈ (Rd)voltage bias and (∂V/∂Φ)current bias ≈ [(∂i/∂Φ)Rd]voltage bias, are always satisfied. For a strongly damped SQUID with βc ≈ 0.25, additional positive feedback (APF) and noise cancellation (NC) were employed to enhance ∂V/∂Φ, the former showing a degradation in the linear flux range but otherwise the same with NC. For a weakly damped SQUID with βc ≈ 3, it is directly connected to the preamplifier without APF or NC, and a low SQUID system noise of about 4 μΦ0/√Hz is measured, which is close to its intrinsic noise.

Chinese Physics B•Nov 1, 2014•2 citations

Superconducting Quantum Interference Devices for Low Frequency Measurements

John L. Clarke

Springer eBooks•Jan 1, 1977•57 citations
We propose a readout scheme for high-T c dc-SQUIDs (superconducting quantum interference devices) with alternating current bias and synchronized offset flux. By use of this scheme, low-frequency noise due to critical current fluctuations, which exist in grain boundary junctions, can be canceled. The readout electronics are simple and operation parameters requiring adjustment are minimized. The ac bias scheme has been applied to YBCO step-junction SQUIDs, where partial reduction of the equivalent flux noise below 100 Hz is observed.
A simple approach to understanding and analyzing direct readout schemes for superconducting quantum interference devices (SQUIDs) is presented. It is shown that the existing methods for suppression of room temperature amplifier noise are based on voltage feedback and current feedback in the SQUID, that were introduced in the original schemes of additional positive feedback and bias current feedback. It is also shown that the way the SQUID is biased (at constant current or voltage) does not affect the noise suppression.
We investigate niobium thin film superconducting quantum interference devices (SQUIDs) with different Steward—McCumber parameters βc operated in both current- and voltage-bias modes. We experimentally prove that there is no difference between the two bias modes with respect to the SQUID intrinsic noise and the noise contribution from the preamplifier. Furthermore, the relationships of the SQUID dynamic parameters, (Rd)current bias ≈ (Rd)voltage bias and (∂V/∂Φ)current bias ≈ [(∂i/∂Φ)Rd]voltage bias, are always satisfied. For a strongly damped SQUID with βc ≈ 0.25, additional positive feedback (APF) and noise cancellation (NC) were employed to enhance ∂V/∂Φ, the former showing a degradation in the linear flux range but otherwise the same with NC. For a weakly damped SQUID with βc ≈ 3, it is directly connected to the preamplifier without APF or NC, and a low SQUID system noise of about 4 μΦ0/√Hz is measured, which is close to its intrinsic noise.