  We report an investigation of perovskite-type LaNiO3 thin films by Raman
scattering in both various scattering configurations and as a function of
temperature. The room-temperature Raman spectra and the associated phonon mode
assignment provide reference data for phonon calculations and for the use of
Raman scattering for structural investigations of LaNiO3, namely the effect of
strain in thin films or heterostructures. The temperature-dependent Raman
spectra from 80 to 900 K are characterized by the softening of the rotational
A1g mode, which suggest a decreasing rhombohedral distortion towards the ideal
cubic structure with increasing temperature.
