  We report neutron scattering measurements of critical magnetic excitations in
the weakly ferromagnetic superconductor UCoGe. The strong non-Landau damping of
the excitations we observe, although unusual has been found in another related
ferromagnet, UGe2 at zero pressure. However, we also find there is a
significant anisotropy of the magnetic correlation length in UCoGe that
contrasts with an almost isotropic length for UGe2. The values of the magnetic
correlation length and damping are found to be compatible with
superconductivity on small Fermi surface pockets. The anisotropy may be
important to explain why UCoGe is a superconductor at zero pressure while UGe2
is not.
