  We report results of an investigation of the temperature dependence of the
magnon and phonon frequencies in NiO. A combination of Brillouin - Mandelstam
and Raman spectroscopies allowed us to elucidate the evolution of the phonon
and magnon spectral signatures from the Brillouin zone center (GHz range) to
the second-order peaks from the zone boundary (THz range). The
temperature-dependent behavior of the magnon and phonon bands in the NiO
spectrum indicates the presence of antiferromagnetic (AF) order fluctuation or
a persistent AF state at temperatures above the Neel temperature (T=523 K).
Tuning the intensity of the excitation laser provides a method for
disentangling the features of magnons from acoustic phonons without the
application of a magnetic field. Our results are useful for interpretation of
the inelastic-light scattering spectrum of NiO, and add to the knowledge of its
magnon properties important for THz spintronic devices.
