  Quantum coherence of electrons in ferromagnetic metals is difficult to assess
experimentally. We report the first measurements of time-dependent universal
conductance fluctuations in ferromagnetic metal (Ni$_{0.8}$Fe$_{0.2}$)
nanostructures as a function of temperature and magnetic field strength and
orientation. We find that the cooperon contribution to this quantum correction
is suppressed, and that domain wall motion can be a source of
coherence-enhanced conductance fluctuations. The fluctuations are more strongly
temperature dependent than those in normal metals, hinting that an unusual
dephasing mechanism may be at work.
