151. An ab initio study of MgO epitaxial layers on a Co2MnSi (0 0 1) surface: influence of the interface structure on tunnelling conductance.
- Author
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Yu, H. L., Jiang, X. F., Zheng, Y., and Yang, G. W.
- Subjects
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MAGNESIUM oxide , *TUNNEL magnetoresistance measurement , *SPIN polarization , *ORBITAL hybridization , *THERMODYNAMIC potentials , *GIBBS' free energy - Abstract
The formation of MgO epitaxial layers on a Co2MnSi (0 0 1) surface was studied using the ab initio electronic structure calculations based on the density functional theory. The free energy calculations showed that the O-rich, O-top and Mg-rich configurations in the CoCo termination case, and the O-rich and O-top configurations in the MnSi termination case were thermodynamically stable. The magnetic and electronic properties of these stable configurations were investigated in detail, and the results indicated that only the Mg-rich configuration with CoCo termination exhibited near half-metallic properties at the interface. The influence of the interfacial structure on the tunnelling conductance of the Co2MnSi/MgO/Co2MnSi magnetic tunnel junctions (MTJs) was also discussed using the nonequilibrium Green's function method. The attained conductance showed that a large difference of up to 104 was observed in the magnitude of parallel conductance, which means that the interface structure plays a crucial role in the electronic transport of the MTJ. These findings are useful in designing MTJs with high performance. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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