  We have identified low-energy magnetic excitations in a doped quantum
critical system by means of polarized neutron scattering experiments. The
presence of these excitations could explain why
Ce(Fe$_{0.76}$Ru$_{0.24}$)$_2$Ge$_2$ displays dynamical scaling in the absence
of local critical behavior or long-range spin-density wave criticality. The
low-energy excitations are associated with the reorientations of the superspins
of fully ordered, isolated magnetic clusters that form spontaneously upon
lowering the temperature. The system houses both frozen clusters and dynamic
clusters, as predicted by Hoyos and Vojta [Phys. Rev. B 74, 140401 (R) (2006)].
