The CoFeB/MgO interface is important not only because of its ability to act as a good spin filter, but also because it exhibits significant magnetic interface anisotropy. However, there is experimental evidence that the mineral kotoite (Mg3B2O6) forms at this interface, possibly as a result of B diffusion into the oxide. Recent calculations have demonstrated that kotoite is a surprisingly good spin filter material, despite the lack of cubic symmetry. It is not a priori clear how the perpendicular anisotropy is affected if kotoite forms at the interface. Hereby, we have performed first-principles density functional calculations to investigate the magnetic anisotropy of CoFe/kotoite interfaces. We find that the Co/Fe atoms bind strongly to O atoms of kotoite, and the CoFe/kotoite interfaces exhibit strong perpendicular magnetic anisotropy (PMA) comparable to that of CoFe/MgO interfaces. Analysis of the electronic structure shows that CoFe states having dxz and dyz character are strongly affected by the magnetization direction and play an important role in determining the magnetic anisotropy of both CoFe/kotoite and CoFe/MgO interfaces. Our observations are consistent with previous experimental observations of PMA. We demonstrate that the interface properties are only weakly affected by the formation of kotoite compared to MgO.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2013 May 2|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics