  We report measurements of the flux-dependent orbital magnetic susceptibility
of an ensemble of 10^5 disconnected silver rings at 217 MHz. Because of the
strong spin-orbit scattering rate in silver this experiment is a test of
existing theories on orbital magnetism. Below 100 mK the rings exhibit a
magnetic signal with a flux periodicity of h/2 e consistent with averaged
persistent currents, whose amplitude is estimated to be of the order of 0.3 nA.
The sign of the oscillations indicates diamagnetism in the vicinity of zero
magnetic field. This sign is not consistent with theoretical predictions for
average persistent currents unless considering attractive interactions in
silver. We propose an alternative interpretation taking into account spin orbit
scattering and finite frequency.

Mesoscale and Nanoscale Physics