Correlating DC SQUID Performance with the Location of Trapped Magnetic Flux Using Scanning SQUID Microscopy
Abstract
Holes in the ground planes of superconducting circuits, commonly referred to as moats, are known to be an effective means of mitigating the deleterious effects of residual magnetic flux in superconducting circuits. Previous studies have utilized scanning SQUID microscopy (SSM) to image the effectiveness of various moat geometries and the maximum magnetic fields where they no longer prevent vortices in the ground plane but have not directly correlated the location of flux with circuit performance measurements. In this study we employ SSM to image the effectiveness of various moat configurations in trapping unwanted flux near a DC SQUID, and when the moats are not effective, the location of vortices in the ground plane. During the same cooldown, and without disturbing the circuit, we measure the circuit performance to directly correlate this with the vortex location. We show that there are preferential pinning sites for fluxons regardless of moat configuration, demonstrating the utility of the SSM in provide feedback for circuit layout, modeling, and failure analysis.
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BibTeX
@misc{xu2026correlating,
title = {{Correlating DC SQUID Performance with the Location of Trapped Magnetic Flux Using Scanning SQUID Microscopy}},
author = {Bochao Xu and Ian W. Haygood and Kyle Jackman and Coenrad J. Fourie and Pete F. Hopkins and Michael L. Schneider},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.10442},
eprint = {2610.10442},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.10442},
}
RIS
TY - UNPB
TI - Correlating DC SQUID Performance with the Location of Trapped Magnetic Flux Using Scanning SQUID Microscopy
AU - Bochao Xu
AU - Ian W. Haygood
AU - Kyle Jackman
AU - Coenrad J. Fourie
AU - Pete F. Hopkins
AU - Michael L. Schneider
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2610.10442
UR - https://arxiv.org/abs/2610.10442
AB - Holes in the ground planes of superconducting circuits, commonly referred to as moats, are known to be an effective means of mitigating the deleterious effects of residual magnetic flux in superconducting circuits. Previous studies have utilized scanning SQUID microscopy (SSM) to image the effectiveness of various moat geometries and the maximum magnetic fields where they no longer prevent vortices in the ground plane but have not directly correlated the location of flux with circuit performance measurements. In this study we employ SSM to image the effectiveness of various moat configurations in trapping unwanted flux near a DC SQUID, and when the moats are not effective, the location of vortices in the ground plane. During the same cooldown, and without disturbing the circuit, we measure the circuit performance to directly correlate this with the vortex location. We show that there are preferential pinning sites for fluxons regardless of moat configuration, demonstrating the utility of the SSM in provide feedback for circuit layout, modeling, and failure analysis.
ER -