  We propose mechanisms for the spin Hall effect in metallic systems arising
from the coupling between conduction electrons and local magnetic moments that
are dynamically fluctuating. Both a side-jump-type mechanism and a
skew-scattering-type mechanism are considered. In either case, dynamical spin
fluctuation gives rise to a nontrivial temperature dependence in the spin Hall
conductivity. This leads to the enhancement in the spin Hall conductivity at
nonzero temperatures near the ferromagnetic instability. The proposed
mechanisms could be observed in $4d$ or $5d$ metallic compounds.
