Effect of Ce and Zr codoping on the multiferroic properties of BiFeO ₃ thin films

Pure BiFeO₃(BFO), Ce-doped BiFeO₃(BCFO), Zr-doped BiFeO₃(BFZO), as well as Ce- and Zr-codoped BiFeO₃(BCFZO) thin films were successfully prepared on Pt/Ti/SiO₂/Si substrates by chemical solution deposition. The effects of Ce and Zr doping on the structure, surface morphology, electrical and magnetic properties of BFO films were studied. X-ray diffraction and atomic force microscopy analysis revealed structure transition and decreased grain sizes in the doped BFO films. In comparison with the other doped BFO films studied here, the Ce- and Zr-codoped BCFZO film showed the lowest dielectric loss and leakage current density and exhibited a well-squared hysteresis loop with a remanent polarization P _r of 64 μC/cm² and a coercive electric field E _c of 339 kV/cm, as well as the fatigue-free characteristics. Meanwhile, the largest magnetization was also observed in this codoped film. The possible reasons for the enhancement of the ferroelectricity and the ferromagnetism of these films were discussed.