Miura Yoshio, Abe Kazutaka, Shirai Masafumi
Research Institute of Electrical Communication, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
J Phys Condens Matter. 2009 Feb 11;21(6):064245. doi: 10.1088/0953-8984/21/6/064245. Epub 2009 Jan 20.
We investigate and discuss the effects of interfacial oxidation on electronic structures and tunnel conductance of the Co(2)MnSi/MgO/Co(2)MnSi(001) magnetic tunnel junction (MTJ) on the basis of first-principles calculations. It is found that the MnSi termination tends to be oxidized compared with the Co termination because of the relaxation of atomic positions in the MnSi-terminated interface. Furthermore, we found that the single oxide layer inserted on both sides of the junction greatly decreases the tunnel conductance of the MTJ in parallel magnetization. We concluded that the relaxation of the Mn atomic position in the oxidized junction reduces the coupling of the Δ(1) states between the Co(2)MnSi electrode and the MgO barrier and causes significant interfacial scattering of the majority-spin electrons with Δ(1) symmetry at the oxidized layer.
基于第一性原理计算，我们研究并讨论了界面氧化对Co(2)MnSi/MgO/Co(2)MnSi(001)磁性隧道结（MTJ）的电子结构和隧道电导的影响。研究发现，由于MnSi端界面处原子位置的弛豫，与Co端相比，MnSi端更容易被氧化。此外，我们发现，在结的两侧插入单氧化层会大大降低平行磁化时MTJ的隧道电导。我们得出结论，氧化结中Mn原子位置的弛豫降低了Co(2)MnSi电极与MgO势垒之间Δ(1)态的耦合，并导致氧化层处具有Δ(1)对称性的多数自旋电子发生显著的界面散射。
