Effect of annealing atmosphere on structural and multiferroic properties of BiFeO3 thin film prepared by RF magnetron sputtering

BFO thin films were deposited on Pt substrate by RF magnetron sputtering technology. The effects of annealing atmosphere on the phase evolution, microstructure, surface element chemical state, leakage current density, dielectric, ferroelectric and magnetic properties of BFO thin films were systematically investigated. The XRD analyses reveal that O-2 annealing atmosphere benefits to prepare single phase BFO thin film compared with air. AFM images demonstrate that BFO thin film annealed in O-2 shows smaller grain size and better surface roughness than that annealed in air. The XPS analyses clarify that Fe2+ and Fe3+ ions are co-existed in both obtained BFO thin films, while BFO thin film annealed in O-2 shows lower Fe2+ and oxygen vacancy concentration. Comparing with BFO thin film annealed in air, BFO thin film annealed in O-2 shows a lower leakage current density of 4.4 x 10(-6) A/cm(2) with enhanced dielectric, ferroelectric and magnetic properties. Our results provide useful reference for practical application of BFO thin film prepared by RF magnetron sputtering.