Perpendicular magnetic tunnel junction with W seed and capping layers

H. Almasi; C. L. Sun; X. Li; T. Newhouse-Illige; C. Bi; K. C. Price; S. Nahar; C. Grezes; Q. Hu; P. Khalili Amiri; K. L. Wang; P. M. Voyles; W. G. Wang

doi:10.1063/1.4981878

Perpendicular magnetic tunnel junction with W seed and capping layers

H. Almasi, C. L. Sun, X. Li, T. Newhouse-Illige, C. Bi, K. C. Price, S. Nahar, C. Grezes, Q. Hu, P. Khalili Amiri, K. L. Wang, P. M. Voyles, W. G. Wang

College of Electrical Engineering and Computer Science

Research output: Contribution to journal › Article › peer-review

24 Citations (Scopus)

Abstract

We present a study on perpendicular magnetic tunnel junctions with W as buffer and capping layers. A tunneling magnetoresistance of 138% and an interfacial magnetic anisotropy of 1.67 erg/cm² were obtained in optimally annealed samples. However, after extended annealing at 420 °C, junctions with W layers showed extremely small resistance due to interdiffusion of W into the MgO barrier. In contrast, in Ta-based junctions, the MgO barrier remained structurally stable despite disappearance of magnetoresistance after extended annealing due to loss of perpendicular magnetic anisotropy. Compared with conventional tunnel junctions with in-plane magnetic anisotropy, the evolution of tunneling conductance suggests that the relatively low magnetoresistance in perpendicular tunnel junctions is related to the lack of highly polarized Δ₁ conducting channel developed in the initial stage of annealing.

Original language	English
Article number	153902
Journal	Journal of Applied Physics
Volume	121
Issue number	15
DOIs	https://doi.org/10.1063/1.4981878
Publication status	Published - 2017 Apr 21

All Science Journal Classification (ASJC) codes

General Physics and Astronomy

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10.1063/1.4981878

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title = "Perpendicular magnetic tunnel junction with W seed and capping layers",

abstract = "We present a study on perpendicular magnetic tunnel junctions with W as buffer and capping layers. A tunneling magnetoresistance of 138% and an interfacial magnetic anisotropy of 1.67 erg/cm2 were obtained in optimally annealed samples. However, after extended annealing at 420 °C, junctions with W layers showed extremely small resistance due to interdiffusion of W into the MgO barrier. In contrast, in Ta-based junctions, the MgO barrier remained structurally stable despite disappearance of magnetoresistance after extended annealing due to loss of perpendicular magnetic anisotropy. Compared with conventional tunnel junctions with in-plane magnetic anisotropy, the evolution of tunneling conductance suggests that the relatively low magnetoresistance in perpendicular tunnel junctions is related to the lack of highly polarized Δ1 conducting channel developed in the initial stage of annealing.",

author = "H. Almasi and Sun, {C. L.} and X. Li and T. Newhouse-Illige and C. Bi and Price, {K. C.} and S. Nahar and C. Grezes and Q. Hu and {Khalili Amiri}, P. and Wang, {K. L.} and Voyles, {P. M.} and Wang, {W. G.}",

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doi = "10.1063/1.4981878",

language = "English",

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T1 - Perpendicular magnetic tunnel junction with W seed and capping layers

AU - Almasi, H.

AU - Sun, C. L.

AU - Li, X.

AU - Newhouse-Illige, T.

AU - Bi, C.

AU - Price, K. C.

AU - Nahar, S.

AU - Grezes, C.

AU - Hu, Q.

AU - Khalili Amiri, P.

AU - Wang, K. L.

AU - Voyles, P. M.

AU - Wang, W. G.

PY - 2017/4/21

Y1 - 2017/4/21

N2 - We present a study on perpendicular magnetic tunnel junctions with W as buffer and capping layers. A tunneling magnetoresistance of 138% and an interfacial magnetic anisotropy of 1.67 erg/cm2 were obtained in optimally annealed samples. However, after extended annealing at 420 °C, junctions with W layers showed extremely small resistance due to interdiffusion of W into the MgO barrier. In contrast, in Ta-based junctions, the MgO barrier remained structurally stable despite disappearance of magnetoresistance after extended annealing due to loss of perpendicular magnetic anisotropy. Compared with conventional tunnel junctions with in-plane magnetic anisotropy, the evolution of tunneling conductance suggests that the relatively low magnetoresistance in perpendicular tunnel junctions is related to the lack of highly polarized Δ1 conducting channel developed in the initial stage of annealing.

AB - We present a study on perpendicular magnetic tunnel junctions with W as buffer and capping layers. A tunneling magnetoresistance of 138% and an interfacial magnetic anisotropy of 1.67 erg/cm2 were obtained in optimally annealed samples. However, after extended annealing at 420 °C, junctions with W layers showed extremely small resistance due to interdiffusion of W into the MgO barrier. In contrast, in Ta-based junctions, the MgO barrier remained structurally stable despite disappearance of magnetoresistance after extended annealing due to loss of perpendicular magnetic anisotropy. Compared with conventional tunnel junctions with in-plane magnetic anisotropy, the evolution of tunneling conductance suggests that the relatively low magnetoresistance in perpendicular tunnel junctions is related to the lack of highly polarized Δ1 conducting channel developed in the initial stage of annealing.

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DO - 10.1063/1.4981878

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JO - Journal of Applied Physics

JF - Journal of Applied Physics

IS - 15

M1 - 153902

ER -

Perpendicular magnetic tunnel junction with W seed and capping layers

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