  Superconducting metamaterials are utilized to study the approach to the
plasmonic limit simply by tuning temperature to modify the superfluid density,
and thus the superfluid plasma frequency. We examine the persistence of
artificial magnetism in a metamaterial made with superconductors in the
plasmonic limit, and compare to the electromagnetic behavior of normal metals
as a function of frequency as the plasma frequency is approached from below.
Spiral-shaped Nb thin film meta-atoms of scaled dimensions are employed to
explore the plasmonic behavior in these superconducting metamaterials, and the
scaling condition allows extraction of the temperature dependent superfluid
density, which is found to be in good agreement with expectations.
