Improved multiferroic properties in (Ho, Mn) co-doped BiFeO3 thin films prepared by chemical solution deposition

Pure BiFeO3 (BFO), Bi0.92Ho0.08FeO3 (BHFO) and Bi0.92Ho0.08Fe0.97Mn0.03O3 (BHFMO) films were successfully deposited on FTO/glass substrates by chemical solution deposition method. X-ray diffraction, Rietveld refinement and Raman spectra results demonstrate that a structural transition from rhombohedral (R3c:H) to biphasic structure (R3c:H+R-3m:R) occurs in BHFC and BHFMO films. The improved dielectric properties, leakage current, fentelectric properties and ferromagnetic properties are obtained by co-doping Ho and Mn. A giant remanent polarization (2P(r)similar to 231.4 mu C/cm(2)) is observed in BHFMO film. In addition, the dramatically decreased leakage current density (4.02 x 10(-4) A/cm(2) at 400 kV/cm) is obtained in BHFMO film, which is about two orders of magnitude lower than that of pure BFO. The superior ferroelectric properties of BHFMO film are mainly attributed to the structure transition and low leakage current. Furthermore, BHOFMO film shows enhanced ferromagnetism (M-s similar to 2.74 emu/cm(3)), implying the collapse of space modulated spin structure by the structural transition. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.