  The magnetic excitations in Sr$_2$RuO$_4$ are studied by polarized and
unpolarized neutron scattering experiments as a function of temperature. At the
scattering vector of the Fermi-surface nesting with a half-integer out-of-plane
component, there is no evidence for the appearance of a resonance excitation in
the superconducting phase. The body of existing data indicates weakening of the
scattered intensity in the nesting spectrum to occur at very low energies. The
nesting signal persists up to 290 K but is strongly reduced. In contrast, a
quasi-ferromagnetic contribution maintains its strength and still exhibits a
finite width in momentum space.
