  We compared the AC magnetic susceptibility behaviour for the vortex glass
phase and for the creep phenomena with an inhomogeneous pinning potential. The
temperature dependence of the harmonics of the susceptibility have been
numerically simulated with these two models, and we studied them as a function
of the frequency, in terms of Cole-Cole plots. From our analysis we show that
it is possible to distinguish between the two different phases, because of
their clear differences in the Cole-Cole plots behaviour with the frequency.
