Electronic Structure of BiFe_1-xM_xO₃ (M=Mn and Co) Thin Films by Soft-X-Ray Spectroscopy

Abstract

The electronic structures of BiFe_0.96Mn_0.04O₃ and BiFe_0.96Co_0.04O₃ thin films have studied by X-ray absorption spectroscopy and soft-X-ray emission spectroscopy. The BiFe_0.96Mn_0.04O₃ thin film has the mixed valence states of Mn³⁺ and Mn⁴⁺, although the BiFe_0.96Co_0.04O₃ thin film has the valence state of Co³⁺. The conduction band consists of the Fe 3d state. The valence band is mainly composed of the O 2p state hybridized with the Fe 3d state. The bandwidth of valence band depends on the valence state of doped element. The energy gap of BiFe_0.96Mn_0.04O₃ thin film is smaller than that of BiFe_0.96Co_0.04O₃ thin film. These findings may indicate that the leakage current of thin film is closely related with the electronic structure and energy gap.