Magneto-optical studies of SrGa_0.7 Co_0.3 O_{3 - δ} perovskite thin films with embedded cobalt nanoparticles

Sr(Ga_0.7 Co_0.3) O_{3 - δ}/Co perovskite/metal thin films have been systematically studied by means of Faraday and Kerr magneto-optical spectroscopies. The samples were prepared by pulsed laser deposition on (001) (LaAlO₃) 0.3(Sr₂AlTaO₆) 0.7 (LSAT) and Si substrates, and grew as a perovskite matrix containing approximately 6% by volume of embedded metallic Co nanoparticles with diameter less than 20nm, which were distributed throughout the film and at the film-substrate interface. The film thickness ranged from 130 to 310nm. The perovskite matrix was single crystal on LSAT and polycrystalline on Si. The magneto-optical spectroscopy was carried out in both Faraday and Kerr configurations in the photon energy range from 0.5 to 5eV in magnetic fields sufficient for sample saturation, showing a strong thickness dependence of the magneto-optical effect. This dependence was attributed to the different metallic Co content, nanoparticle size, and accumulation at the film-substrate interface.