La0.7Sr0.3MnO3 (LSMO) thin films grown by pulsed laser deposition on SrTiO3 (STO) substrates with (1 0 0) and (1 1 0) crystallographic orientations are characterized by means of magneto-optic (MO) 'Kerr' spectroscopy at polar and longitudinal magnetizations combined with spectroscopic ellipsometry (SE) in the photon energy range between 1.2 and 4.8 eV. The LSMO film thickness, t, ranges from 10 to 50 nm.
Amplitudes in the permittivity tensor spectra, determined from the MO and SE data, depend on t and substrate orientation.