Fabrication of Multiferroic Co-Substituted BiFeO(3) Epitaxial Films on SrTiO(3) (100) Substrates by Radio Frequency Magnetron Sputtering

The 10 at.% Co-substituted BiFeO(3) films (of thickness 50 nm) were successfully prepared by radio frequency (r.f.) magnetron sputtering on SrTiO(3) (100) substrates with epitaxial relationships of [001](001)Co-BiFeO(3)//[001](001)SrTiO(3). In this study, a single phase Co-substituted BiFeO(3) epitaxial film was fabricated by r.f. magnetron sputtering. Sputtering conditions such as Ar, O(2) gas pressure, annealing temperature, annealing atmosphere, and sputtering power were systematically changed. It was observed that a low Ar gas pressure and low sputtering power is necessary to suppress the formation of the secondary phases of BiO(x). The Co-substituted BiFeO(3) films were crystalized with post-annealing at 600 °C in air. The process window for single phase films is narrower than that for pure BiFeO(3) epitaxial films. By substituting Fe with Co in BiFeO(3), the magnetization at room temperature increased to 20 emu/cm(3). This result suggests that Co-substituted BiFeO(3) films can be used in spin-filter devices.