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.

Ferroelectric Metal in Tetragonal BiCoO3/BiFeO3 Bilayers and Its Electric Field Effect

“…2 . For BFO, the charge transfer gap is determined by the filled oxygen 2 p band and the unoccupied 3 d band of Fe, and the calculated band gap of 1.93 eV is in good agreement with previous calculations 49 , but inconsistent with the experimental value of 3.10 eV 50 , as a result of using the LSDA approximation. The Fe spins are antiparallel and the corresponding DOS is symmetrical, so we only show one.…”

Structural investigation of (111) oriented (BiFeO3)(1-x)Λ/(LaFeO3)xΛ superlattices by X-ray diffraction and Raman spectroscopy

“…Its ferroelectric and magnetic properties are related respectively to the Bi 3+ lone pair (6s 2 orbital) and Fe 3+ ions. The promising piezoelectric properties and the large polarization which exceeds 100µC/cm 2 in (111) oriented films (the polarization is directed along [111]) make BFO thin films as an alternative to lead based materials for electromechanical applications 6 .…”

Mechanism of Fluorescence Enhancement of Biosynthesized XFe2O4–BiFeO3 (X = Cr, Mn, Co, or Ni) Membranes

“…The peak e g (6.8 eV) is ascribed to the electronic transition from O–2p to X–2p in tetrahedron of XFO. Here, it should be noted that the O–O hybridization in the interface enhances two weak interfacial coupling peaks of nanoscale spinel at near-infrared range, due to that two-dimensional electron gases exist at the (i) X–Fe (e − or h + ) and (ii) O–O (h + ) interfaces [28]. The Mulliken charges confirm that two small peaks (frequency, 14 eV and 21 eV) correspond mainly to the X–Fe and O–O interfaces.…”