Influence of Resonances on the Noise Performance of SQUID Susceptometers
Abstract
Scanning Superconducting Quantum Interference Device (SQUID) Susceptometry simultaneously images the local magnetic fields and susceptibilities above a sample with sub-micron spatial resolution. Further development of this technique requires a thorough understanding of the current, voltage, and flux ( IVΦ ) characteristics of scanning SQUID susceptometers. These sensors often have striking anomalies in their current–voltage characteristics, which we believe to be due to electromagnetic resonances. The effect of these resonances on the performance of these SQUIDs is unknown. To explore the origin and impact of the resonances, we develop a model that qualitatively reproduces the experimentally-determined IVΦ characteristics of our scanning SQUID susceptometers. We use this model to calculate the noise characteristics of SQUIDs of different designs. We find that the calculated ultimate flux noise is better in susceptometers with damping resistors that diminish the resonances than in susceptometers without damping resistors. Such calculations will enable the optimization of the signal-to-noise characteristics of scanning SQUID susceptometers.
Additional Information
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Received: 4 November 2019; Accepted: 27 December 2019; Published: 30 December 2019. We would like to thank Diana Chamaki for making some of the IV measurements of damped susceptometers presented in this paper. Author Contributions: Conceptualization, J.R.K.; Formal analysis, S.I.D. and J.R.K.; Funding acquisition, K.A.M.; Software, S.I.D. and J.R.K.; Writing–original draft, S.I.D. and J.R.K.; Writing–review and editing, S.I.D. and J.R.K. All authors have read and agreed to the published version of the manuscript. This research received no external funding. The authors declare no conflict of interest.Attached Files
Published - sensors-20-00204-v2.pdf
Submitted - 1911.03836.pdf
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Additional details
- PMCID
- PMC6983001
- Eprint ID
- 100463
- Resolver ID
- CaltechAUTHORS:20200102-140920652
- Created
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2020-01-03Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field