  In femtosecond demagnetization experiments, one gains access to the
elementary relaxation mechanisms of a magnetically ordered spin system on a
time scale of 100 fs. Following these experiments, we report a combined
micromagnetic and experimental study that connects the different regimes known
from all-optical pump-probe experiments by employing a simple micromagnetic
model. We identify spin-wave packets on the nanometer scale that contribute to
the remagnetization process on the intermediate time scale between single-spin
relaxation and collective precession.
