Oxygen partial pressure dependence of magnetic, optical and magneto-optical properties of epitaxial cobalt-substituted SrTiO 3 films

Cobalt-substituted SrTiO3 films (SrTi0.70Co0.30O3-δ) were grown on SrTiO3 substrates using pulsed laser deposition under oxygen pressures ranging from 1 μTorr to 20 mTorr. The effect of oxygen pressure on structural, magnetic, optical, and magneto-optical properties of the films was investigated. The film grown at 3 μTorr has the highest Faraday rotation (FR) and magnetic saturation moment (Ms). Increasing oxygen pressure during growth reduced Ms, FR and optical absorption in the near-infrared. This trend is attributed to decreasing Co2+ ion concentration and oxygen vacancy concentration with higher oxygen partial pressure during growth.