The structural and multiferroic properties of Bi_((1-x))Ce_xFe_((1-x))(Mg_(0.5)Ti_(0.5))xO_3 thin films

摘要

Bi_(((1-x))Ce_xFe_((1-x))(Mg_(0.5)Ti_(0.5))_xO_3 (x=0, 0.05, 0.10, 0.20, 0.25) thin films were synthesized by a sol-gel method. The structural, electrical and magnetic properties of Bi_((1-x))Ce_xFe_((1-x))(Mg_(0.5)Ti_(0.5))_xO_3 (x=0, 0.05, 0.10, 0.20, 0.25) thin films have been investigated. BiFeO_3 thin film possessed a perovskite-type rhombohedral structure with space group R3c, and the average grain size decreased as the concentration of Ce, Mg and Ti co-doping increased. The leakage current densities of BiFeO_3 co-doping with Ce, Mg and Ti ions exhibited a significant reduction compared with that of BiFeO_3 thin film. Compared with the leakage current density of BiFeO_3 thin film (4.19×10~(-4) A/cm~2), the leakage current density of Bi_(0.80)Ce_(0.20)Fe_(0.80)Mg_(0.10)Ti_(0.10)O_3 thin film was reduced by about four orders of magnitude (1.05 × 10~(-8) A/cm~2) under the electric field of 300 kV/cm. Well-defined ferroelectric loops were obtained and the polarization increased with the increase of Ce, Ti and Mg co-doping. The remanent polarization of Bi_(0.80)Ce_(0.20)Fe_(0.80)Mg_(0.10)Ti_(0.10)O_3 thin film (2P_r ~34.9 μC/cm~2) was approximately four times larger than that of pure BiFeO_3 (2P_r ~7.8 uC/cm~2) under the applied field of 300 kV/cm. The magnetization under 10 kOe magnetic field of Bi_((1-x))Ce_xFe_((1-x))(Mg_(0.5)Ti_(0.5))_xO_3 thin films increased with the increasing concentration of Ce, Mg and Ti co-doping. The improvement of magnetic behaviors for BiFeO_3 co-doping with Ce, Mg and Ti ions thin films were observed significantly, cooperating with the enhanced ferroelectricity which indicated that BiFeO_3 co-doping with Ce, Mg and Ti ions thin films will be the promising materials in the application to magnetoelectric devices.