Boron diffusion induced symmetry reduction and scattering in CoFeB/MgO/CoFeB magnetic tunnel junctions

被引：29
作者：
Bai, Zhaoqiang [1 ,2 ]
Shen, Lei [1 ]
Wu, Qingyun [1 ]
Zeng, Minggang [1 ]
Wang, Jian-Sheng [1 ]
Han, Guchang [2 ]
Feng, Yuan Ping [1 ]
机构：
[1] Natl Univ Singapore, Dept Phys, Singapore 117542, Singapore
[2] Agcy Sci Technol & Res, Data Storage Inst, Singapore 117608, Singapore
来源：
PHYSICAL REVIEW B | 2013年 / 87卷 / 01期
关键词：
ROOM-TEMPERATURE; MAGNETORESISTANCE;
D O I：
10.1103/PhysRevB.87.014114
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
By first-principles analysis, we investigate the effect of thermal annealing on structural stability of CoFeB/MgO(thin)/CoFeB magnetic tunnel junctions. The calculated phonon dispersion indicates that Mg3B2O6 (kotoite) is a stable spacer after annealing due to B diffusion into MgO. The calculated tunneling magnetoresistance (TMR) of CoFe/kotoite/CoFe is 210%, which is in good agreement with the available experimental value and 2 orders of magnitude lower than the predicted values of CoFe/MgO/CoFe junctions. The physics of this more realistic TMR value is the change in symmetry from C-4v of MgO to C-2v of kotoite. Such symmetry reduction induces scattering and weakens the tunneling transmission of the Delta(1)-like Bloch states. Our calculations also reveal that the tunneling transmission is sensitive to the electrode/spacer interfacial chemical bonding. Residual boron, localized at the interface due to insufficient annealing temperature, can further reduce the TMR. DOI: 10.1103/PhysRevB.87.014114
引用
收藏
页数：6
相关论文
共 36 条
  • [1] Compositional change of MgO barrier and interface in CoFeB/MgO/CoFeB tunnel junction after annealing
    Bae, J. Y.
    Lim, W. C.
    Kim, H. J.
    Lee, T. D.
    Kim, K. W.
    Kim, T. W.
    [J]. JOURNAL OF APPLIED PHYSICS, 2006, 99 (08)
  • [2] Magnetic and transport properties of Mn3-xGa/MgO/Mn3-xGa magnetic tunnel junctions: A first-principles study
    Bai, Zhaoqiang
    Cai, Yongqing
    Shen, Lei
    Yang, Ming
    Ko, Viloane
    Han, Guchang
    Feng, Yuanping
    [J]. APPLIED PHYSICS LETTERS, 2012, 100 (02)
  • [3] Effect of interface states on spin-dependent tunneling in Fe/MgO/Fe tunnel junctions
    Belashchenko, KD
    Velev, J
    Tsymbal, EY
    [J]. PHYSICAL REVIEW B, 2005, 72 (14)
  • [4] Density-functional method for nonequilibrium electron transport -: art. no. 165401
    Brandbyge, M
    Mozos, JL
    Ordejón, P
    Taylor, J
    Stokbro, K
    [J]. PHYSICAL REVIEW B, 2002, 65 (16) : 1654011 - 16540117
  • [5] Atomic and electronic structure of the CoFeB/MgO interface from first principles
    Burton, J. D.
    Jaswal, S. S.
    Tsymbal, E. Y.
    Mryasov, O. N.
    Heinonen, O. G.
    [J]. APPLIED PHYSICS LETTERS, 2006, 89 (14)
  • [6] Spin-dependent tunneling conductance of Fe|MgO|Fe sandwiches -: art. no. 054416
    Butler, WH
    Zhang, XG
    Schulthess, TC
    MacLaren, JM
    [J]. PHYSICAL REVIEW B, 2001, 63 (05)
  • [7] Atomic-scale spectroscopic imaging of CoFeB/Mg-B-O/CoFeB magnetic tunnel junctions
    Cha, J. J.
    Read, J. C.
    Egelhoff, W. F., Jr.
    Huang, P. Y.
    Tseng, H. W.
    Li, Y.
    Buhrman, R. A.
    Muller, D. A.
    [J]. APPLIED PHYSICS LETTERS, 2009, 95 (03)
  • [8] 230% room-temperature magnetoresistance in CoFeB/MgO/CoFeB magnetic tunnel junctions
    Djayaprawira, DD
    Tsunekawa, K
    Nagai, M
    Maehara, H
    Yamagata, S
    Watanabe, N
    Yuasa, S
    Suzuki, Y
    Ando, K
    [J]. APPLIED PHYSICS LETTERS, 2005, 86 (09) : 1 - 3
  • [9] Oxygen-Vacancy-Induced Diffusive Scattering in Fe/MgO/Fe Magnetic Tunnel Junctions
    Ke, Youqi
    Xia, Ke
    Guo, Hong
    [J]. PHYSICAL REVIEW LETTERS, 2010, 105 (23)
  • [10] Disorder scattering in magnetic tunnel junctions: Theory of nonequilibrium vertex correction
    Ke, Youqi
    Xia, Ke
    Guo, Hong
    [J]. PHYSICAL REVIEW LETTERS, 2008, 100 (16)
1234