Half-metallic interface and coherent tunneling in Co2YZ/MgO/Co2YZ (YZ = MnSi,CrAl) magnetic tunnel junctions:: A first-principles study

被引：88

作者：

Miura, Yoshio ^{[1
]}

Uchida, Hirohisa ^{[1
]}

Oba, Yoshihiro ^{[1
]}

Abe, Kazutaka ^{[1
]}

Shirai, Masafumi ^{[1
]}

机构：

[1] Tohoku Univ, Elect Commun Res Inst, Aoba Ku, Sendai, Miyagi 9808577, Japan

来源：

PHYSICAL REVIEW B | 2008年 / 78卷 / 06期

关键词：

D O I：

10.1103/PhysRevB.78.064416

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We present first-principles based calculations of electronic structures and tunneling conductance of Co(2)YZ/MgO(similar to 2 nm)/Co(2)YZ(001) (YZ = MnSi, CrAl) magnetic tunnel junctions (MTJs). It is found that YZ(MnSi and CrAl)-terminated interfaces are thermodynamically stable as compared with Co-terminated interfaces in Co(2)YZ/MgO(001) junctions. In the CrAl-termination, no interface states appear in both sides of the junctions, preserving the half metallicity of Co2CrAl, while reduction of the spin polarization is significant in the MnSi termination. Co2CrAl, however, has no Delta(1) band at the Fermi level, thus the majority-spin conductance of Co2CrAl/MgO/Co2CrAl(001) MTJs in the parallel magnetization is much smaller than that of Co2MnSi/MgO/Co2MnSi(001) MTJs. We propose that MTJs having an ultrathin Co2CrAl layer between Co2MnSi electrode and MgO barrier, i.e., Co2MnSi/Co2CrAl/MgO(001) junctions, can derive both the half-metallic character at the interface and the large tunneling conductance through the Delta(1) channel in the parallel magnetization.

引用

页数：9

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