Effective strategy for optimizing the leakage current and ferroelectric polarization characteristics of BiFeO3_PVDF-TrFE nanocomposite films

BiFeO3 has been extensively studied as an important single-phase multiferroic material at room temperature in the application fields of energy storage, data storage, spintronics, and electro-magnetic sensors. However, the high leakage current caused by the presence of lattice defects such as vacancies constrains the further development of BiFeO3. In this paper, we presented a facile method to overcome the high leakage problem via blending BiFeO3 nanoparticles into the ferroelectric copolymer PVDF-TrFE matrix and introducing a barrier layer beneath the top Pt dot electrode. The leakage current and ferroelectric characteristics of BiFeO3_PVDF-TrFE nanocomposite films were discussed comprehensively. Consequently, compared with the composites without the barrier layer, the leakage current density of the BiFeO3_PVDF-TrFE composite films reduced two orders of magnitude after coating a pure copolymer layer. Moreover, the remnant ferroelectric polarization reached ~14 μC cm−2 for a moderate weight content (25 wt%) of BiFeO3 nanoparticle in the blends, with a remarkably smaller coercive electric field than that of pure PVDF-TrFE films. An electrical conduction blocking mechanism was established to elucidate the optimized electric and ferroelectric properties of nanocomposite films.