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Chesca Applied Physics Letters 20 October 2015.pdf (1.95 MB)

Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K

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journal contribution
posted on 2015-11-18, 13:58 authored by Boris Chesca, Daniel John, Christopher Mellor
A very promising direction to improve the sensitivity of magnetometers based on superconducting quantum interference devices (SQUIDs) is to build a series-array of N non-interacting SQUIDs operating flux-coherently, because in this case their voltage modulation depth, ΔV, linearly scales with N whereas the white flux noise SΦ 1/2 decreases as 1/N1/2. Here, we report the realization of both these improvements in an advanced layout of very large SQUID arrays made of YBa2Cu3O7. Specially designed with large area narrow flux focusers for increased field sensitivity and improved flux-coherency, our arrays have extremely low values for SΦ 1/2 between (0.25 and 0.44) μΦ0/Hz1/2 for temperatures in the range (77-83) K. In this respect, they outperform niobium/aluminium trilayer technology-based single-SQUIDs operating at 4.2 K. Moreover, with values for ΔV and transimpedance in the range of (10-17) mV and (0.3-2.5) kΩ, respectively, a direct connection to a low-noise room temperature amplifier is allowed, while matching for such readout is simplified and the available bandwidth is greatly increased. These landmark performances suggest such series SQUID arrays are ideal candidates to replace single-SQUIDs operating at 4.2 K in many applications. © 2015 AIP Publishing LLC.

History

School

  • Science

Department

  • Physics

Published in

Applied Physics Letters

Volume

107

Issue

16

Citation

CHESCA, B., JOHN, D. and MELLOR, C., 2015. Flux-coherent series SQUID array magnetometers operating above 77 K with superior white flux noise than single-SQUIDs at 4.2 K. Applied Physics Letters, 107 (16), 162602.

Publisher

© American Institute of Physics

Version

  • VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

2015-09-14

Publication date

2015-10-20

Notes

This paper was published in the journal, Applied Physics Letters [© American Institute of Physics]. It is also available at: http://dx.doi.org/10.1063/1.4932969

ISSN

0003-6951

eISSN

1077-3118

Language

  • en

Article number

162602

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