Electronic and magnetic structure of Fe3O4/BiFeO3 multiferroic superlattices: First principles calculations

Abstract

Fe3O4/BiFeO3(001) superlattices comprising multiferroic BiFeO3 and ferrimagnetic half-metallic Fe3O4 have been investigated using first principles calculations. Two models were simulated: Model (a) contains the interfaces of Fe(A)−BiO and Fe2O4(B)−FeO2; Model (b) contains the interfaces of Fe(A)−FeO2 and Fe2O4(B)−BiO. The magnetization enhances 13% and 8% for models (a) and (b) due to the interfacial bonding between Fe(A)/Fe(B) and Bi atoms, respectively. The much larger enhancement in model (a) is ascribed to the facts that the Fe(A) atoms are surrounded by relatively less O atoms than Fe(B) in model (b), which increases the hybridization between Fe(A) and Bi atoms. The calculated results suggest that the number of oxygen atoms at the interfaces plays an important role on determining the interfacial coupling strength. Meanwhile, the interfacial bonding also affects the spin polarization of the Fe3O4 at the interface.