Influence of Resonances on the Noise Performance of SQUID Susceptometers.

Autor: Davis SI; Department of Physics, Stanford University, Stanford, CA 94305-4045, USA.; California Institute of Technology-The Division of Physics, Mathematics and Astronomy, 1200 E California Blvd, Pasadena, CA 91125, USA., Kirtley JR; Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA., Moler KA; Department of Physics, Stanford University, Stanford, CA 94305-4045, USA.; Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA.; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA.; Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
Jazyk: angličtina
Zdroj: Sensors (Basel, Switzerland) [Sensors (Basel)] 2019 Dec 30; Vol. 20 (1). Date of Electronic Publication: 2019 Dec 30.
DOI: 10.3390/s20010204
Abstrakt: 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 ( I V Φ ) 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 I V Φ 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.
Databáze: MEDLINE
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