Leakage current of multiferroic (Bi_(0.6)Tb_(0.3)La_(0.10)FeO_3 thin films grown at various oxygen pressures by pulsed laser deposition and annealing effect

摘要

Thin films of multiferroic (Bi_(0.6)Tb_(0.3)La_(0.1))FeO_3 were grown on Pt/Ti/SiO_2/Si substrate under various oxygen pressures by pulsed laser deposition technique. X-ray diffraction patterns show that the crystallinity of the thin film is improved with decreasing depositing oxygen pressure and the thin film grown at a lower oxygen pressure of 0.01 torr exhibits a single perovskite phase with preferred (001) orientation. Leakage current of the as-deposited thin films decreases with decreasing grown oxygen pressure. Significantly, the leakage current of the thin films can be reduced largely by an annealing process at 800℃ with flowing oxygen. The annealed thin films show a relatively high resistivity and stable polarization loops with double remnant polarization of about 3 μC/cm~2. The conduction properties of the thin films have been well analyzed, and it is indicated that the dominant conduction mechanism is the space-charge-limited conduction for the thin film grown at higher oxygen pressure and the Poole-Frenkel conduction for the thin films grown at lower oxygen pressure.