Linear and quadratic magneto-optical effects observed in La$_{0.7}$Sr$_{0.3}$MnO$_3$ thin films in transmitted light

Magnetic linear dichroism (MLD) is observed in polycrystalline La$_{0.7}$Sr$_{0.3}$MnO$_3$ films in transmitted light. The spectral and temperature dependences of the MLD are determined for the energy $E$ of the light wave ranging from $1.5$ to $3.5$ eV. The experimental spectra are fitted by a sum of Lorentzian curves. The MLD spectrum exhibits more features in comparison to the spectra of magnetic circular dichroism (MCD), which we measured earlier using the same film samples. Various temperature behaviors of the intensities of the Lorentzian components centered at different $E$ values have been revealed. This can be related to the effect of the surface states on the magneto-optical characteristics of the samples.