  A broad effort is underway to understand and harness the interaction between
superconductors and spin-active color centers with an eye on the realization of
hybrid quantum devices and novel imaging modalities of superconducting
materials. Most work, however, overlooks the complex interplay between either
system and the environment created by the color center host. Here we use an
all-diamond scanning probe to investigate the spin dynamics of a single
nitrogen-vacancy (NV) center proximal to a high-critical-temperature
superconducting film in the presence of a weak magnetic field. We find that the
presence of the superconductor increases the NV spin coherence lifetime, a
phenomenon we tentatively rationalize as a change in the electric noise due to
a superconductor-induced redistribution of charge carriers near the NV site. We
build on these findings to demonstrate transverse-relaxation-time-weighted
imaging of the superconductor film. These results shed light on the complex
surface dynamics governing the spin coherence of shallow NVs while
simultaneously paving the route to new forms of noise spectroscopy and imaging
of superconductors.
