Preparation of composition-and valence-controlled BiFeO_3 thin films and investigation of leakage mechanism

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We investigated leakage mechanisms in composition-, valence-and domain structure-controlled epitaxial BiFeO_3 thin films prepared by dual ion beam sputtering. The leakage current was controlled by Poole-Frenkel emission independently of the composition ; AFM revealed the presence ofμm-sized local leakage spots with high conductivity. These results suggest that uniformity in composition and a large amount of charged traps can be the origin of a larger leakage than that in Pb-based ferroelectric thin films. Therefore, an improvement in composition uniformity and a decrease in charge traps will be indispensable to reduce the leakage in BiFeO_3 thin films.