The structural and multiferroic properties of Bi_(1−x)Ce _x Fe_(1−x)(Mg_0.5Ti_0.5) _x O₃ thin films

Bi_(1−x)Ce _x Fe_(1−x)(Mg_0.5Ti_0.5) _x O₃ (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 _x Fe_(1−x)(Mg_0.5Ti_0.5) _x O₃ (x = 0, 0.05, 0.10, 0.20, 0.25) thin films have been investigated. BiFeO₃ 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 BiFeO₃ co-doping with Ce, Mg and Ti ions exhibited a significant reduction compared with that of BiFeO₃ thin film. Compared with the leakage current density of BiFeO₃ thin film (4.19 × 10⁻⁴ A/cm²), the leakage current density of Bi_0.80Ce_0.20Fe_0.80Mg_0.10Ti_0.10O₃ thin film was reduced by about four orders of magnitude (1.05 × 10⁻⁸ A/cm²) 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_0.80Ce_0.20Fe_0.80Mg_0.10Ti_0.10O₃ thin film (2P _r  ~34.9 μC/cm²) was approximately four times larger than that of pure BiFeO₃ (2P _r  ~7.8 μC/cm²) under the applied field of 300 kV/cm. The magnetization under 10 kOe magnetic field of Bi_(1−x)Ce _x Fe_(1−x)(Mg_0.5Ti_0.5) _x O₃ thin films increased with the increasing concentration of Ce, Mg and Ti co-doping. The improvement of magnetic behaviors for BiFeO₃ co-doping with Ce, Mg and Ti ions thin films were observed significantly, cooperating with the enhanced ferroelectricity which indicated that BiFeO₃ co-doping with Ce, Mg and Ti ions thin films will be the promising materials in the application to magnetoelectric devices.