Magnetic flux trapping is a significant hurdle limiting the reliability and scalability of superconducting electronics, yet tools for imaging flux vortices remain slow or insensitive. We present a cryogenic widefield NV-diamond magnetic microscope capable of rapid, micrometer-scale imaging of flux trapping in superconducting devices. Using this technique, we measure vortex expulsion fields in Nb thin films and patterned strips, revealing a crossover in expulsion behavior between 10 and 20μm strip widths. The observed scaling agrees with theoretical models and suggests the influence of film defects on vortex expulsion dynamics. This instrument enables high-throughput magnetic characterization of superconducting materials and circuits, providing new insight for flux mitigation strategies in scalable superconducting electronics.
@article{arxiv.2506.01906,
title = {Flux-trapping characterization for superconducting electronics using a cryogenic widefield N-$V$ diamond microscope},
author = {Rohan T. Kapur and Pauli Kehayias and Sergey K. Tolpygo and Adam A. Libson and George Haldeman and Collin N. Muniz and Alex Wynn and Nathaniel J. O'Connor and Neel A. Parmar and Ryan Johnson and Andrew C. Maccabe and John Cummings and Justin L. Mallek and Danielle A. Braje and Jennifer M. Schloss},
journal= {arXiv preprint arXiv:2506.01906},
year = {2026}
}
Comments
9 pages main text (5 figures), 7 pages supplementary information (5 figures)