Microstructure, ferroelectric and dielectric properties in Nd and Ti co-doped BiFeO₃ thin film

Nd (3 %) and Ti (2 %) co-doped BiFeO₃ (BNFTO) thin film was deposited on indium tin oxide-coated glass substrate by a metal organic decomposition process. The BNFTO film exhibits a single perovskite phase with random orientation and good insulating property with low leakage current. Asymmetrical polarization–electric field loops are observed in the BNFTO film: This is mainly attributed to the role of oxygen vacancy-related defect complexes in the film. Additionally, the capacitance of the sample is strongly dependent on both the applied voltage and measuring frequency. Furthermore, with the increase in applied voltages or decrease in frequencies, the dielectric tunability is gradually enhanced. The related physics mechanism for the enhanced performance is also discussed. High dielectric constant of 165, dielectric tunability of 27 % and figure of merit of 13.5 are achieved when a measuring frequency of 1 kHz is applied. These present results can be regarded as a base for further development of high-performance BiFeO₃ films.

Polarization–electric field (P–E) and capacitance–voltage (C–V) curves of the BNFTO film measured under various electric fields and applied bias voltages.