Structure transition and multiferroic properties of Mn-doped BiFeO3 thin films

Pure BiFeO3 (BFO) and Mn-doped BiFe1-yMnyO3 thin films were prepared on FTO/glass (SnO2: F) substrates by using a sol-gel method. The effects of Mn-doping on the structure and electric properties of the BFO thin films were studied. The X-ray diffraction (XRD) analysis reveals a structure transition in the Mn-doped BiFe0.96Mn0.04O3 (BFMO) thin film. The Rietveld refined XRD patterns conform the trigonal (R3c: H) and tetragonal (P422) symmetry for the BFO and BFMO thin films, respectively. The structure transition and the mixed valences of Mn ions substantially improve the electric properties of the BFMO thin film. The remnant polarization (P (r)) of the BFMO thin film was 105.86 mu C/cm(2) at 1 kHz in the applied electric field of 865 kV/cm. At an applied electric field of 150 kV/cm, the leakage current density of BFMO thin film is 1.42 x 10(-5) A/cm(2). It is about two orders of magnitude lower than that of the pure BFO thin film (1.25 x 10(-3) A/cm(2)). And the enhanced saturated magnetization of the BFMO thin film is 4.45 emu/cm(3).