Synthesis of Fe3O4 thin films by selective oxidation with controlled oxygen chemical potential

  Based on the calculated Fe–O stability diagram, single-phase Fe3O4 films with tunable magnetic properties were fabricated on Si(0 0 1) substrates by selective oxidation with a CO2(g)/CO(g) mixture. The Fe3O4 phase formation during oxidation was verified by several analysis techniques. In the samples oxidized for short times, Fe3O4 and Fe coexist, and magnetization measurements show biaxial magnetic anisotropy. The Fe3O4 film thickness increases with increasing annealing time, with magnetization loops showing decreasing saturation magnetization, increasing coercive fields, and decreasing in-plane magnetic anisotropy.