First-principles study of perpendicular magnetic anisotropy in CoFe/MgO and CoFe/Mg3B2O6 interfaces

作     者：K. H. Khoo G. Wu M. H. Jhon M. Tran F. Ernult K. Eason H. J. Choi C. K. Gan 

作者机构：Institute of High Performance Computing Agency for Science Technology and Research 1 Fusionopolis Way #16-16 Connexis Singapore 138632 Data Storage Institute Agency for Science Technology and Research DSI Building 5 Engineering Drive 1 Singapore 117608 Department of Physics and IPAP Yonsei University Seoul 120-749 Korea 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2013年第87卷第17期

页      面：174403-174403页

核心收录：

学科分类：07[理学] 0702[理学-物理学] 

基　　金：IHPC-DSI [ZHF/CK/555/0610/A*STAR] NRF of Korea [2011-0018306] 

主　　题：MAGNETIC anisotropy INTERFACES (Physical sciences) ELECTRONIC structure OXIDE minerals MAGNETIZATION 

摘      要：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.