Phase transition and enhanced multiferroic properties of (Sm, Mn and Cr) co-doped BiFeO3 thin films

Pure BiFeO3 (BFO) and (Sm, Mn, Cr) co-doped Bi0.89Sm0.11Fe0.94Mn0.04Cr0.02O3 (BSFMCO) thin films were prepared on FTO/glass (SnO2:F) substrates via a sol-gel method. Structures of BFO and BSFMCO thin films were investigated by X-ray diffraction (XRD), Rietveld refinement of XRD patterns and Raman scattering spectra. The results indicated a phase transition from trigonal (R3c:H) BFO thin film to tetragonal (P4) BSFMCO thin film. The BSFMCO thin film exhibited enhanced multiferroic properties compared to the BFO thin film. The improved remnant polarization (2Pr=109.95 μC/cm2) and saturated magnetization (Ms=1.22 emu/cm3) have been observed in the BSFMCO thin film. At an applied electric field of 150 kV/cm, the leakage current density of the BSFMCO thin film is 1.58×10−6 A/cm2, which is about three orders of magnitude lower than that of the BFO thin film (1.25×10−3 A/cm2).