Atomic-scale mechanisms for achieving ultra-high controllable electrical properties in perovskite BiFeO3

Abstract

Defect engineering strategies are usually expected to enhance electrical, thermal, and optical functionality while tuning the mechanical properties of materials. Here, we employe atomic-scale imaging to characterize the atomic structural positions in bismuth ferrite (BFO)BFO films and demonstrate the precise positions of quantitatively doped ions within the BFO unit cell. Well-controlled oxygen vacancy contents in BFO crystals were engineered via the accurate introduction of Zr and Mn ions, resulting in extraordinary and stable large-signal ferroelectric properties (Pr ∼ 206.2 µC/cm2 and J ∼ 2.2×10-9 A/cm2), magnetic properties (0.53 emu/cm³) and a reduced bandgap (Eg = 2.16 eV). Furthermore, we used computational processing to obtain the coupling of the spin and charge redistributions of iron, resulting in changes in spontaneous polarization. An atomic-scale study enhanced our understanding of the effects of chemical modifications on the ferroelectricity/ferromagnetism structure. This defect engineering approach enables us to customize and optimize local ferroelectric and ferromagnetic order parameters, providing a foundation for designing functionalities in a wide range of functional material systems.