Two-Phase Coexistence and Multiferroic Properties of Cr-Doped BiFeO3 Thin Films

Pure BiFeO 3 (BFO) and Cr-doped BiFe 0.97 Cr 0.03O3 (BFCO) thin films were successfully prepared on F-doped SnO 2 conductive film (FTO)/glass (SnO 2: F) substrates by a sol–gel method. The effect of Cr doping on the structure, ferroelectric, and ferromagnetic properties of the BFO and BFCO thin films have been investigated. X-ray diffraction, Rietveld refined X-ray diffraction (XRD) patterns, and Raman spectroscopy results clearly reveal that the BFCO thin film is characterized by the coexistence of two phases (trigonal and tetragonal). Moreover, the various leakage mechanisms of both thin films have also been studied. The improved ferroelectricity with remnant polarization (Pr) of about 2Pr = 68.68 μC/cm 2 under an applied electric field of 1,181.8 kV/cm and enhanced ferromagnetism with saturation magnetization (Ms) of Ms = 0.93 emu/cm 3 have been observed in the BFCO thin film. The improved electrical properties of the BFCO thin film are ascribed to the coexistence of trigonal and tetragonal phase and high valence of Cr 6+, and the Fe–O 6 octahedron distortion is enhanced due to the overlap and hybridization of Fe 3d/Cr 3d and O 2p orbits by Cr doping.