The effects of La substitution on ferroelectric domain structure and multiferroic properties of epitaxially grown BiFeO_3 thin films

摘要

We report the influence of La substitution in epitaxial BiFeO_3 thin films prepared by pulsed layer deposition on a Nb-doped SrTiO_3 substrate, focusing on ferroelectric domain structure, leakage current, and multiferroic properties. Enhanced ferroelectric remanent polarization and reduced leakage current density were established via La substitution in the BiFeO_3 film. Based on leakage conduction mechanism and piezoelectric force microscopy studies, this is indicative of reduced trap densities and increased domain energy. Besides that, the ferromagnetic properties were improved by the La doping as well. The possible mechanisms for the enhancement of electrical and multiferroic characteristics are extensively discussed.