Characterization of dissipative regions of a N-doped superconducting radio-frequency cavity

• DOI: 10.3389/femat.2023.1235918
• Publication Date: 2023-08-16T09:28:21Z
• Authors: Eric M. Lechner; Basu Dev Oli; Junki Makita; Gianluigi Ciovati; Alex Gurevich; Maria Iavarone
• Keywords: Superconducting radio frequency

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