Magnetization reversal of perpendicular magnetic anisotropy regulated by ferroelectric polarization in CoFe3N/BaTiO3 heterostructures: first-principles calculations

Exploring the electric-field switching of perpendicular magnetic anisotropy (PMA) in multiferroic heterostructures has important physical significance, which attracts great interest due to its promising application for energy-efficient information storage. Herewith, we investigate the effect of ferroelectric polarization on magnetic anisotropy in CoFe₃N/BaTiO₃ heterostructures using first-principles calculations. The calculations reveal that the magnetic anisotropy of CoFe₃N can be regulated by ferroelectric polarization of BaTiO₃. When the ferroelectric polarization reverses, the PMA of FeCo-TiO₂ and FeN-BaO configurations remains, but in the FeN-TiO₂ and FeCo-BaO cases, magnetic anisotropy inverses between out-of-plane and in-plane direction. Further orbital-resolved analysis indicates that the transition of magnetic anisotropy is mainly attributed to the orbital hybridization of interfacial Fe/Co atoms with O atoms induced by the magnetoelectric effect. This study may open an effective approach toward modulating PMA and lays a foundation to the development of low energy consumption memory devices.

Electric field tunable half-metallic characteristic at Fe3O4/BaTiO3 interfaces

The interfacial electronic structure of Fe₃O₄/BaTiO₃ heterostructures was investigated using first-principles calculations.

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

By first-principles calculations we investigate the electronic structure of tetragonal BiCoO₃/BiFeO₃ bilayers with different terminations. The multiferroic insulator BiCoO₃ and BiFeO₃ transform into metal in all of three models. Particularly, energetically favored model CoO₂-BiO exhibits ferroelectric metallic properties, and external electric field enhances the ferroelectric displacements significantly. The metallic character is mainly associated to e_g electrons, while t_2g electrons are responsible for ferroelectric properties. Moreover, the strong hybridization between e_g and O p electrons around Fermi level provides conditions to the coexistence of ferroelectric and metallic properties. These special behaviors of electrons are influenced by the interfacial electronic reconstruction with formed Bi-O electrovalent bond, which breaks O_A-Fe/Co-O_B coupling partially. Besides, the external electric field reverses spin polarization of Fe/Co ions efficiently, even reaching 100%.

Prediction of large magnetoelectric coupling in Fe4N/BaTiO3 and MnFe3N/BaTiO3 junctions from a first-principles study

The large magnetoelectric effects are predicted in Fe₄N/BaTiO₃ and MnFe₃N/BaTiO₃ junctions.

First principles prediction of interfacial magnetoelectric coupling in tetragonal La2/3Sr1/3MnO3/BiFeO3 multiferroic superlattices

The electronic structure and magnetic properties of the tetragonal La2/3Sr1/3MnO3/BiFeO3 multiferroic superlattices with different interfacial terminations have been studied by first-principles calculations. Our results for all the models of the tetragonal La2/3Sr1/3MnO3/BiFeO3 superlattices exhibit a metallic electronic structure. More importantly, we find that the magnetoelectric coupling can be realized in the tetragonal La2/3Sr1/3MnO3/BiFeO3 heterostructures by means of exchange bias, which can be attributed to the interfacial exchange coupling. These findings are useful for magnetoelectrically controlled spintronic devices.

Superior Properties of Energetically Stable La(2/3)Sr(1/3)MnO(3)/Tetragonal BiFeO3 Multiferroic Superlattices

The superlattice of energetically stable La2/3Sr1/3MnO3 and tetragonal BiFeO3 is investigated by means of density functional theory. The superlattice as a whole exhibits a half-metallic character, as is desired for spintronic devices. The interfacial electronic states and exchange coupling are analyzed in details. We demonstrate that the interfacial O atoms play a key role in controlling the coupling. The higher ferroelectricity of tetragonal BiFeO3 and stronger response to the magnetic moments in the La2/3Sr1/3MnO3/BiFeO3 superlattice show a strongly enhanced electric control of the magnetism as compared to the rhombohedral one. Therefore, it is particularly practical interest in the magnetoelectrically controlled spintronic devices.