Magnetic properties of In2O3 containing Fe3O4 nanoparticles

Films of Fe-doped In2O3 that were deliberately fabricated so they contained Fe3O4 nanoparticles were deposited on sapphire substrates by pulsed laser deposition at low oxygen pressure. The concentration of Fe was varied between 1% and 5%, and the effect of including 5% of Sn and vacuum annealing were also investigated. Structural analysis indicated a high concentration of Fe3O4 nanoparticles that caused substantial values of the coercive field at room temperature. Transport measurements indicated that the films were metallic, and an anomalous Hall effect was observed for the sample with 5% of Fe. The concentration of nanoparticles was reduced dramatically by the inclusion of 5% of Sn. Magnetic circular dichroism spectra taken in field and at remanence were analyzed to show that the samples had a magnetically polarized defect band located below the conduction band as well as magnetic Fe3O4 nanoparticles. The signal from the defect states near the band edge was enhanced by increasing the number of carriers by either including Sn or by annealing in vacuum.