Document Type

Article

Publication Date

2023

DOI

10.3389/femat.2023.1235918

Publication Title

Frontiers in Electronic Materials

Volume

3

Pages

1-14

Abstract

We report radio-frequency measurements of quality factors and temperature mapping of a nitrogen doped Nb superconducting RF cavity. Cavity cutouts of hot and cold spots were studied with low temperature scanning tunneling microscopy and spectroscopy, X-ray photoelectron spectroscopy and secondary electron microscopy. Temperature mapping revealed a substantial reduction of the residual resistance upon cooling the cavity with a greater temperature gradient and hysteretic losses at the quench location, pointing to trapped vortices as the dominant source of residual surface resistance.Analysis of the tunneling spectra in the framework of a proximity effect theory shows that hot spots have a reduced pair potential and a wider distribution of the contact resistance between the Nb and the top Nb oxide. Alone, these degraded superconducting properties account for a much weaker excess dissipation as compared with the vortex contribution. Based on the correlation between the quasiparticle density of states and temperature mapping, we suggest that degraded superconducting properties may facilitate vortex nucleation or settling of trapped flux during cooling the cavity through the critical temperature.

Rights

© 2023 Lechner, Oli, Makita, Ciovati, Gurevich and lavarone.

This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0). The use, distribution or reproduction in other forums is permitted, provided the original authors and the copyright owners are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

Data Availability

Article states: "The raw data supporting the conclusion of this article will be made available by the authors, without undue reservation."

Original Publication Citation

Lechner, E. M., Oli, B. D., Makita, J., Ciovati, G., Gurevich, A., & Iavarone, M. (2023). Characterization of dissipative regions of a N-doped superconducting radio-frequency cavity. Frontiers in Electronic Materials, 3, 1-14, Article 1235918. https://doi.org/10.3389/femat.2023.1235918

ORCID

0000-0003-0759-8941 (Gurevich)

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