Structural, electric and multiferroic properties of Sm-doped BiFeO3 thin films prepared by the sol–gelprocess

Pure polycrystalline Bi1−xSmxFeO3 (BSFO) (x=0–0.12) thin films were successfully prepared on FTO/glass substrates by the sol–gel method. The influence of Sm doping on the structure, dielectric, leakage current, ferroelectric and ferromagnetic properties of the BSFO films was investigated. X-ray diffraction analysis and FE-SEM images both reveal a gradual rhombohedra to pseudo-tetragonal phase transition with the increase of Sm dopant content. On one hand, a proper amount of Sm doping can decrease the leakage current densities of the BSFO thin films. On the other hand, excess Sm substitution for Bi will lead to multiphase coexistence in the film, the lattice inhomogeneity results in more defects in the film, which can increase the leakage current density. The result shows that defects in the complexes lead to electric domain back-switching in the BSFOx=0.06 thin film, resulting in a decreased dielectric constant, leakage current and remanent polarization. The BSFOx=0.09 thin film is promising in practical application because of its highest dielectric constant, remanent polarization and remanent magnetization of 203–185, 70 μC/cm2 and 1.31 emu/cm3, respectively.