  We present wideband microwave measurements (1-22 GHz) taken on
Superconductor/Ferromagnet heterostructures with the Corbino disk technique. We
apply the technique to Nb/PdNi/Nb trilayers in the vortex state and we compare
the results to data taken with the same technique on a Nb thin film. We show
that it is possible to directly extract the genuine flux-flow resistivity from
our frequency-dependent measurements without overcoming the (depinning)
critical current. The characteristic frequency for vortex relaxation can also
be estimated, without resorting to a specific model. We find that the F layer
determines a weakening of pinning and an enhancement of the flux-flow
resistivity with respect to the Nb film.
