Optimization of the multiferroic BiFeO_3 thin films by divalent ion (Mn, Ni) co-doping at 6-sites

摘要

Multiferroic BiFe_(0.96-x)Mn_(0.04)Ni_xO_3 (BFMNO) thin films were prepared on fluorine doped tin oxide (FTO) substrates by the chemical solution deposition (CSD) method. X-ray diffraction, Rietveld refinement and Raman spectra reveal the structural transition from rhombohedral (R3c:H) to the biphasic structure (R3c: H + R3m:R) with Mn/Ni co-doping. The X-ray photoelectron spectroscopy analysis confirms the coexistence of Fe~(3+) and Fe~(2+) ions in the thin films. The lower leakage current density (8.1 × 10~(-6) A/cm~2 at 300 kV/cm) via co-doping is obtained. The two-phase coexistence of BFMN_3O gives rise to the superior ferroelectric (2P_r=226.4 μC/cm~2) and the enhanced ferromagnetic properties (M_s= 15.9 emu/cm~3).