  We present neutron scattering spectra taken from a single crystal of
Na0.75CoO2, the precursor to a novel cobalt-oxide superconductor. The data
contain a prominent inelastic signal at low energies (~10 meV), which is
localized in wavevector about the origin of two-dimensional reciprocal space.
The signal is highly dispersive, and decreases in intensity with increasing
temperature. We interpret these observations as direct evidence for the
existence of ferromagnetic spin fluctuations within the cobalt-oxygen layers.
