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

Applied Physics Letters

Use of super Schottky diodes in a cryogenic radio frequency superconducting quantum interference device readout

Michael Mück, Th. Becker, Christoph Heiden

Published Jan 16, 1995• 2 citations
Publisher

Abstract

We describe the fabrication and characterization of super Schottky diodes which are used in the cryogenic part of a 3 GHz radio frequency superconducting quantum interference device (rf SQUID) readout electronics. The diodes were prepared on silicon wafers with an n-doping level of 5×1024 m−3. They exhibited sensitivities of 1500 V−1 at 4.2 K, and a noise equivalent power of 2×10−15 W/√Hz was measured at 2.1 GHz. Using planar niobium 3 GHz rf SQUIDs and a cooled rf amplifier, experiments have been performed to investigate the feasibility of these super Schottky diodes for demodulation of the SQUID rf signal voltage. A simple cryogenic rf SQUID readout, employing two transistors and one super Schottky diode is described and investigated. Flux noise measurements in an open loop have been performed using this readout.

DOI
10.1063/1.114218

Related papers

Investigation of silicon field-effect transistors in cryogenic amplifiers for radio frequency superconducting quantum interference devices

T. Becker, Michael Mück, Christoph Heiden

We have prepared n-channel silicon field-effect transistors, which are capable of working at liquid helium temperatures (4.2 K) and used them in cooled preamplifiers for rf superconducting quantum interference device (SQUID) readout electronics. All metallizations of these transistors were made of niobium, to study the possibility of a further integration of a SQUID and FET on the same chip. Using the FETs in a cooled preamplifier together with a rf SQUID gradiometer, the flux noise of the system could be reduced by a factor of 3 compared to a room temperature low noise preamplifier. We have also performed calculations of a possible increase of the substrate temperature due to the power dissipation of the FET and have measured the cross talk between FET and SQUID.

Review of Scientific Instruments•May 1, 1995•0 citations

Investigation and reduction of excess low-frequency noise in rf superconducting quantum interference devices

Michael Mück, Christoph Heiden, John L. Clarke

A detailed study has been made of the low-frequency excess noise of rf superconducting quantum interference devices (SQUIDs), fabricated from thin niobium films and operated at 4.2 K, with rf bias frequencies of 0.15, 1.7, and 3 GHz. When the SQUIDs were operated in an open-loop configuration in the absence of low-frequency flux modulation, the demodulated rf voltage exhibited a substantial level 1/f noise, which was essentially independent of the rf bias frequency. As the rf bias frequency was increased, the crossover frequency at which the 1/f noise power was equal to the white noise power moved to higher frequencies, because of the reduction in white noise. On the other hand, when the SQUID was flux modulated at 50 kHz and operated in a flux locked loop, no 1/f noise was observed at frequencies above 0.5 Hz. A detailed description of how the combination of rf bias and flux modulation removes 1/f noise due to critical current fluctuations is given. Thus, the results demonstrate that the 1/f noise observed in these SQUIDs is generated by critical current fluctuations, rather than by the hopping of flux vortices in the niobium films.

Journal of Applied Physics•May 1, 1994•26 citations

Improved sensitivity of planar microwave based RF-SQUIDs using a cryogenic HEMT preamplifier

Giorgio Fontana, R. Mezzena, Stefano Vitale +4 more

The design and performance of a planar microwave RF-SQUID (superconducting quantum interference device) read out by a cryogenic high-electron-mobility-transistor (HEMT) preamplifier are described. The SQUID sensor consists of a planar half-wavelength microstrip resonator, into which the SQUID loop is integrated. The SQUID is operated at a pump frequency of 1.7 GHz. The cryogenic preamplifier uses a microwave HEMT, located close to the SQUID sensor. Measurements of the flux noise and the fractional step rise parameter were carried out in the temperature range between 4.2 K and 1.5 K. In an open loop, a flux noise of 2*10/sup -6/ Phi /sub 0// square root Hz was measured at 4.2 K, resulting in an energy resolution of about 100 h. The design of a 3-GHz magnetometer is also described, and the preliminary results of the measurements are reported.>

IEEE Transactions on Applied Superconductivity•Mar 1, 1993•5 citations

High-TC rf superconducting quantum interference device readout with a cryogenic preamplifier

Dongfeng He, M. Tachiki, Hideo Itozaki

A high-TC rf superconducting quantum interference device (SQUID) readout with a cryogenic preamplifier was developed. The noise figure of the preamplifier at 350MHz was about 0.92dB at room temperature and 0.35dB at 77K. For a high-TC yttrium barium copper oxide rf SQUID coupled with a lumped element tank circuit with a resonant frequency of about 360MHz, the white flux noise was about 25μΦ0∕√Hz and 22μΦ0∕√Hz when the preamplifier was at room temperature and at 77K, respectively. The flux noise was only reduced by about 12% using the cryogenic preamplifier. As the thermal noise of the SQUID and the noise generated by the tank circuit are already higher than the preamplifier noise, cooling the preamplifier has only a small effect of the system noise, when the SQUID is operated at 77K. Lower operating temperatures, e.g., when using a SQUID made from MgB2, might justify the use of a cooled preamplifier.

Review of Scientific Instruments•Jun 1, 2006•0 citations

Review of low-noise radio-frequency amplifiers based on superconducting quantum interference device

Y.H. Lee, Yonuk Chong, Yannis Kyriakos Semertzidis

Superconducting quantum interference device (SQUID) is a sensitive detector of magnetic flux signals. Up to now, the main application of SQUIDs has been measurements of magnetic flux signals in the frequency range from near DC to several MHz. Recently, cryogenic low-noise radio-frequency (RF) amplifiers based on DC SQUID are under development aiming to detect RF signals with sensitivity approaching quantum limit. In this paper, we review the recent progress of cryogenic low-noise RF amplifiers based on SQUID technology.

Progress in Superconductivity and Cryogenics•Dec 31, 2014•0 citations

Cryogenic direct current superconducting quantum interference device readout circuit

Michael Mück, Matthias Korn, Chas Mugford +1 more

We have designed and tested a superconducting quantum interference device (SQUID) readout circuit, which can be operated at liquid helium temperatures. Although room-temperature SQUID electronics perform well, it is sometimes desirable to keep the wires between SQUID, readout electronics, and feedback coil as short as possible to minimize phase shifts and time delays. Cooling the readout circuit to low temperatures can also decrease its thermal noise. Our readout circuit uses conventional ac-flux modulation, which significantly reduces low frequency excess noise and drift in the preamplifier. In this case, simple complementary metal–oxide–semiconductor circuits with low power dissipation can be used as amplifier, phase-sensitive detector and integrator. The power dissipation of the complete readout is less than 15mW at 5V supply voltage.

Review of Scientific Instruments•Jun 27, 2005•4 citations
We describe the fabrication and characterization of super Schottky diodes which are used in the cryogenic part of a 3 GHz radio frequency superconducting quantum interference device (rf SQUID) readout electronics. The diodes were prepared on silicon wafers with an n-doping level of 5×1024 m−3. They exhibited sensitivities of 1500 V−1 at 4.2 K, and a noise equivalent power of 2×10−15 W/√Hz was measured at 2.1 GHz. Using planar niobium 3 GHz rf SQUIDs and a cooled rf amplifier, experiments have been performed to investigate the feasibility of these super Schottky diodes for demodulation of the SQUID rf signal voltage. A simple cryogenic rf SQUID readout, employing two transistors and one super Schottky diode is described and investigated. Flux noise measurements in an open loop have been performed using this readout.
We have prepared n-channel silicon field-effect transistors, which are capable of working at liquid helium temperatures (4.2 K) and used them in cooled preamplifiers for rf superconducting quantum interference device (SQUID) readout electronics. All metallizations of these transistors were made of niobium, to study the possibility of a further integration of a SQUID and FET on the same chip. Using the FETs in a cooled preamplifier together with a rf SQUID gradiometer, the flux noise of the system could be reduced by a factor of 3 compared to a room temperature low noise preamplifier. We have also performed calculations of a possible increase of the substrate temperature due to the power dissipation of the FET and have measured the cross talk between FET and SQUID.
A detailed study has been made of the low-frequency excess noise of rf superconducting quantum interference devices (SQUIDs), fabricated from thin niobium films and operated at 4.2 K, with rf bias frequencies of 0.15, 1.7, and 3 GHz. When the SQUIDs were operated in an open-loop configuration in the absence of low-frequency flux modulation, the demodulated rf voltage exhibited a substantial level 1/f noise, which was essentially independent of the rf bias frequency. As the rf bias frequency was increased, the crossover frequency at which the 1/f noise power was equal to the white noise power moved to higher frequencies, because of the reduction in white noise. On the other hand, when the SQUID was flux modulated at 50 kHz and operated in a flux locked loop, no 1/f noise was observed at frequencies above 0.5 Hz. A detailed description of how the combination of rf bias and flux modulation removes 1/f noise due to critical current fluctuations is given. Thus, the results demonstrate that the 1/f noise observed in these SQUIDs is generated by critical current fluctuations, rather than by the hopping of flux vortices in the niobium films.
The design and performance of a planar microwave RF-SQUID (superconducting quantum interference device) read out by a cryogenic high-electron-mobility-transistor (HEMT) preamplifier are described. The SQUID sensor consists of a planar half-wavelength microstrip resonator, into which the SQUID loop is integrated. The SQUID is operated at a pump frequency of 1.7 GHz. The cryogenic preamplifier uses a microwave HEMT, located close to the SQUID sensor. Measurements of the flux noise and the fractional step rise parameter were carried out in the temperature range between 4.2 K and 1.5 K. In an open loop, a flux noise of 2*10/sup -6/ Phi /sub 0// square root Hz was measured at 4.2 K, resulting in an energy resolution of about 100 h. The design of a 3-GHz magnetometer is also described, and the preliminary results of the measurements are reported.>
A high-TC rf superconducting quantum interference device (SQUID) readout with a cryogenic preamplifier was developed. The noise figure of the preamplifier at 350MHz was about 0.92dB at room temperature and 0.35dB at 77K. For a high-TC yttrium barium copper oxide rf SQUID coupled with a lumped element tank circuit with a resonant frequency of about 360MHz, the white flux noise was about 25μΦ0∕√Hz and 22μΦ0∕√Hz when the preamplifier was at room temperature and at 77K, respectively. The flux noise was only reduced by about 12% using the cryogenic preamplifier. As the thermal noise of the SQUID and the noise generated by the tank circuit are already higher than the preamplifier noise, cooling the preamplifier has only a small effect of the system noise, when the SQUID is operated at 77K. Lower operating temperatures, e.g., when using a SQUID made from MgB2, might justify the use of a cooled preamplifier.
Superconducting quantum interference device (SQUID) is a sensitive detector of magnetic flux signals. Up to now, the main application of SQUIDs has been measurements of magnetic flux signals in the frequency range from near DC to several MHz. Recently, cryogenic low-noise radio-frequency (RF) amplifiers based on DC SQUID are under development aiming to detect RF signals with sensitivity approaching quantum limit. In this paper, we review the recent progress of cryogenic low-noise RF amplifiers based on SQUID technology.
We have designed and tested a superconducting quantum interference device (SQUID) readout circuit, which can be operated at liquid helium temperatures. Although room-temperature SQUID electronics perform well, it is sometimes desirable to keep the wires between SQUID, readout electronics, and feedback coil as short as possible to minimize phase shifts and time delays. Cooling the readout circuit to low temperatures can also decrease its thermal noise. Our readout circuit uses conventional ac-flux modulation, which significantly reduces low frequency excess noise and drift in the preamplifier. In this case, simple complementary metal–oxide–semiconductor circuits with low power dissipation can be used as amplifier, phase-sensitive detector and integrator. The power dissipation of the complete readout is less than 15mW at 5V supply voltage.