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Title: High-temperature superconducting quantum interference device with cooled LC resonant circuit for measuring alternating magnetic fields with improved signal-to-noise ratio

Abstract

Certain applications of superconducting quantum interference devices (SQUIDs) require a magnetic field measurement only in a very narrow frequency range. In order to selectively improve the alternating-current (ac) magnetic field sensitivity of a high-temperature superconductor SQUID for a distinct frequency, a single-coil LC resonant circuit has been used. Within the liquid nitrogen bath, the coil surrounds the SQUID and couples to it inductively. Copper coils with different numbers of windings were used to cover the frequency range from <1 to nearly 100 kHz. A superconducting coil made of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} tape conductor was also tested. With the LC circuit, the signal-to-noise ratio of measurements could be improved typically by one order of magnitude or more in a narrow frequency band around the resonance frequency exceeding a few kilohertz. The best attained equivalent magnetic field resolution was 2.5 fT/{radical}Hz at 88 kHz. The experimental findings are in good agreement with mathematical analysis of the circuit with copper coil.

Authors:
; ; ; ;  [1];  [2];  [3]
  1. Institute of Bio- and Nanosystem (IBN-2), Research Center Juelich, D-52425 Juelich (Germany) and Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092 (China)
  2. (IBN-2), Research Center Juelich, D-52425 Juelich (Germany)
  3. (Germany)
Publication Date:
OSTI Identifier:
20953454
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 78; Journal Issue: 5; Other Information: DOI: 10.1063/1.2735561; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALTERNATING CURRENT; BARIUM COMPOUNDS; COPPER; HIGH-TC SUPERCONDUCTORS; KHZ RANGE 01-100; LIQUIDS; MAGNETIC FIELDS; MAGNETOMETERS; NITROGEN; RESOLUTION; SIGNAL-TO-NOISE RATIO; SQUID DEVICES; SUPERCONDUCTING COILS; TEMPERATURE RANGE 0400-1000 K; YTTRIUM COMPOUNDS

Citation Formats

Qiu Longqing, Zhang Yi, Krause, Hans-Joachim, Braginski, Alex I., Usoskin, Alexander, Institute of Bio- and Nanosystem, and European High Temperature Superconductors GmbH and Co. KG, D-63450 Hanau. High-temperature superconducting quantum interference device with cooled LC resonant circuit for measuring alternating magnetic fields with improved signal-to-noise ratio. United States: N. p., 2007. Web. doi:10.1063/1.2735561.
Qiu Longqing, Zhang Yi, Krause, Hans-Joachim, Braginski, Alex I., Usoskin, Alexander, Institute of Bio- and Nanosystem, & European High Temperature Superconductors GmbH and Co. KG, D-63450 Hanau. High-temperature superconducting quantum interference device with cooled LC resonant circuit for measuring alternating magnetic fields with improved signal-to-noise ratio. United States. doi:10.1063/1.2735561.
Qiu Longqing, Zhang Yi, Krause, Hans-Joachim, Braginski, Alex I., Usoskin, Alexander, Institute of Bio- and Nanosystem, and European High Temperature Superconductors GmbH and Co. KG, D-63450 Hanau. Tue . "High-temperature superconducting quantum interference device with cooled LC resonant circuit for measuring alternating magnetic fields with improved signal-to-noise ratio". United States. doi:10.1063/1.2735561.
@article{osti_20953454,
title = {High-temperature superconducting quantum interference device with cooled LC resonant circuit for measuring alternating magnetic fields with improved signal-to-noise ratio},
author = {Qiu Longqing and Zhang Yi and Krause, Hans-Joachim and Braginski, Alex I. and Usoskin, Alexander and Institute of Bio- and Nanosystem and European High Temperature Superconductors GmbH and Co. KG, D-63450 Hanau},
abstractNote = {Certain applications of superconducting quantum interference devices (SQUIDs) require a magnetic field measurement only in a very narrow frequency range. In order to selectively improve the alternating-current (ac) magnetic field sensitivity of a high-temperature superconductor SQUID for a distinct frequency, a single-coil LC resonant circuit has been used. Within the liquid nitrogen bath, the coil surrounds the SQUID and couples to it inductively. Copper coils with different numbers of windings were used to cover the frequency range from <1 to nearly 100 kHz. A superconducting coil made of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} tape conductor was also tested. With the LC circuit, the signal-to-noise ratio of measurements could be improved typically by one order of magnitude or more in a narrow frequency band around the resonance frequency exceeding a few kilohertz. The best attained equivalent magnetic field resolution was 2.5 fT/{radical}Hz at 88 kHz. The experimental findings are in good agreement with mathematical analysis of the circuit with copper coil.},
doi = {10.1063/1.2735561},
journal = {Review of Scientific Instruments},
number = 5,
volume = 78,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • We have investigated the performance of YBa[sub 2]Cu[sub 3]O[sub 7[minus][ital x]] dc superconducting quantum interference devices (SQUIDs) cooled in static magnetic fields, [ital B][sub 0], of 0.01--1 mT. For fields less than the earth's ambient field, about 0.05 mT, the white noise of the devices at 77 K is not materially affected. However, at a frequency [ital f] of 1 Hz the spectral density of the 1/[ital f] noise, [ital S][sub [Phi]] (1 Hz), at 0.05 mT increases by an order of magnitude over that for zero field. Furthermore, [ital S][sub [Phi]] (1 Hz) scales approximately linearly with [ital B][submore » 0], suggesting strongly that the noise originates in the motion of vortices in the YBCO film. This increase in noise is likely to be an issue for SQUIDs operated in the earth's field.« less
  • The spectral density {ital S}{sub {Phi}}({ital f}) of the low-frequency 1/{ital f} noise of high transition temperature dc superconducting quantum interference devices (SQUIDs) with narrow linewidths was independent of {ital B}{sub 0}, the magnetic field in which they were cooled, up to a threshold value, about 33 {mu}T in the best case. Above this threshold, which is associated with the entry of flux vortices into the film, the noise increased rapidly. By contrast, for large square washer SQUIDs, {ital S}{sub {Phi}}({ital f}) scaled linearly with {ital B}{sub 0}. Estimates indicate that the 1/{ital f} flux noise produced by the pickupmore » loop of a directly coupled magnetometer is negligible. {copyright} {ital 1996 American Institute of Physics.}« less
  • We have measured the noise of several directly coupled high T{sub c} superconducting quantum interference device (SQUID) magnetometers as we change a static magnetic field B while the devices are superconducting. Devices without {open_quotes}flux dams{close_quotes} show an increase in noise at relatively low magnetic fields B{approximately}1 {mu}T. Devices with flux dams can show no deterioration of the noise characteristics for B as large as 34 {mu}T. The flux dams are part of the pickup loop and limit the circulating current I{sub circ}. If I{sub circ} is kept sufficiently low no vortices are forced into the SQUID loop and the noisemore » performance of the magnetometer remains good. {copyright} {ital 1997 American Institute of Physics.}« less
  • We report the controlled integration, via dip pen nanolithography, of monolayer dots of ferritin-based CoO nanoparticles (12 μ{sub B}) into the most sensitive areas of a microSQUID sensor. The nearly optimum flux coupling between these nanomagnets and the microSQUID improves the achievable sensitivity by a factor 10{sup 2}, enabling us to measure the linear susceptibility of the molecular array down to very low temperatures (13 mK). This method opens the possibility of applying ac susceptibility experiments to characterize two-dimensional arrays of single molecule magnets within a wide range of temperatures and frequencies.
  • In this letter, we present results of experiments in which nuclear magnetic resonance (NMR) signals were detected using an untuned pickup coil coupled to a high temperature superconductor (HTS) based superconducting quantum interference device (SQUID). We were able to operate the HTS SQUID in the presence of static fields of up to 500 Gauss and radio frequency fields of up to 6 Gauss. The ability of a HTS SQUID to detect NMR signals opens up the possibility of using a sensitive detector for practical applications involving NMR that require a broad detection bandwidth. {copyright} {ital 1997 American Institute of Physics.}