Optical and magneto-optical properties of Bi substituted yttrium iron garnets prepared by metal organic decomposition

In this work, we present a systematic study of optical and magneto-optical properties of Y3-xBixFe5O12 thin films with various Bi concentrations (x = 1.5, 2, 2.5, 3) prepared by Metal Organic Decomposition on Gd3Ga5O12 (100) substrates. We used magneto-optical spectroscopy and spectroscopic ellipsometry. Spectral dependence of complex refraction indexes obtained from ellipsometric measurements revealed increasing optical absorption with increasing Bi concentrations. Faraday and Kerr magneto-optical spectra measured in the photon energy range from 1.5 to 5.5 eV clearly demonstrated that the increasing Bi concentration enhances the spin-orbit coupling and influences the magneto-optical effect. Using the magneto-optical and ellipsometric experimental data we deduced a spectral dependence of complete permittivity tensor in a wide spectral range. Comparison of obtained results with the results reported on Liquid Phase Epitaxy bulk-like garnets with small Bi concentrations showed agreement and confirmed a high optical and magneto-optical quality of investigated films.