Optimization of perpendicular anisotropy of Ta-inserted double CoFeB/MgO interface MTJ’s for STT-MRAM

Clark, Billy D.; Paul, Soumalya; Schwarm, Samuel C.; Singh, Amritpal; Natarajarathinam, Anusha; Gupta, Subhadra

doi:10.1016/j.jmmm.2015.09.010

Cited by 7 publications

(5 citation statements)

References 12 publications

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based magnetic random-access memories (MRAM) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and novel spin-based electronics such as spin-torque nanooscillators [20][21][22][23][24][25][26][27][28]. In comparison to materials with a lower anisotropy, PMA offers superior thermal stability for high density device applications [16].

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mentioning

confidence: 99%

[Co/Ni] multilayers with robust post-annealing performance for spintronics device applications

Gupta¹,

Sbiaa²,

Bahri³

et al. 2018

J. Phys. D: Appl. Phys.

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The effect of annealing on the diffusion induced changes in the magnetic and magnetodynamic properties of (Co/Ni) multilayers were investigated. Here, we report, all aspects of post annealing induced effect on perpendicular magnetic anisotropy (PMA), domain morphology, switching mechanism and high frequency magnetization dynamics to understand spin relaxation. (Co/Ni) multilayers of this study exhibited a loop squareness of 95%, a slight drop in saturation magnetization from 650 emu/cc to 620 emu/cc and high magnetic anisotropy (Ku ~ 3 × 105 J m−3) even after annealing at temperatures as high as 400 °C. Successive domain mapping by magnetic force microscopy revealed characteristics of multi-domains stripe that feature at all stages of annealing except at 500 °C, attributed to the loss of PMA, driven by interfacial diffusion. High frequency broadband ferromagnetic resonance measurements showed little effect of annealing on intrinsic damping parameter (α = 0.019–0.024) while inhomogeneous linewidth broadening varied without a clear trend. These results are discussed considering crystallographic modifications and it was found that fcc (1 1 1) texture was retained in the samples until 400 °C post annealing. The retention of a high anisotropy, high magnetization and low damping constant after high temperature annealing makes these Co/Ni multilayers suitable for designing spin torque based memory devices.

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confidence: 99%

[Co/Ni] multilayers with robust post-annealing performance for spintronics device applications

Gupta¹,

Sbiaa²,

Bahri³

et al. 2018

J. Phys. D: Appl. Phys.

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“…Materials such as Ta, Mo, Mg and W are reported as bridge layers to improve the anisotropic properties of the free layer of the MTJ device. The thermal stability coefficient can be improved significantly [137][138][139][140][141]. Zhu et al reported that the spin backflow and spin-memory loss at Pt-based heavy metal/ferromagnet interfaces can be effectively eliminated by inserting an insulating paramagnetic NiO layer with optimized thickness.…”

Section: Relationship Between 2d Materials Interface Effects and Devi...mentioning

confidence: 99%

Review on magnetic/nonmagnetic heterojunction interface effects on spintronic MTJ devices

Yuan,

Jiang

2024

Semicond. Sci. Technol.

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Magnetic tunnel junctions (MTJs), as the core storage unit of magneto resistive random-access memory (MRAM), have received a lot of attention and have a very important position in spintronics. In the MTJ devices, magnetic/nonmagnetic heterojunction structures are included, consisting of magnetic metals and magnetic insulators or nonmagnetic metals. The interface of the heterojunction has certain physical effects that can affect the performance of MTJ devices. In the review, combined with the existing research results, the physical mechanism of magnetic/non-magnetic heterojunction interface coupling is discussed. The influence of the interface effect of the heterojunction on the performance of MTJ devices is studied, and the optimization method is proposed specifically. This work systematically summarizes the interface effect of magnetic/non-magnetic heterojunction.

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“…Loss of interlayer exchange and enhanced Gilbert damping commonly results when a Ta nanolayer is introduced between two magnetic layers [10,11]. Since different magnetic materials such as CoFe and NiFe show different effective 'dead layer' thicknesses, careful MTJ multilayer optimization is an essential step to achieve the desired performance [12]. For industrial applications where magnetron sputtering is used, the precise deposition parameters largely determine the observed 'dead layer' thickness, and Ta nanolayers below ∼0.3 nm essentially act as local doping atoms redistributed in the magnetic film within few angstroms, since ultra-fine sequential Ta/FM deposition (lamination) has been shown to be magnetically equivalent to co-deposition [13].…”

Section: Introductionmentioning

confidence: 99%

Exchange stiffness reduction in Ta substituted NiFe alloys

Strelkov

Timopheev

Dounia

et al. 2023

J. Phys. D: Appl. Phys.

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In magnetic tunnel junctions (MTJ) for memory or sensor applications, insertion of Ta nanolayers at the interface of or within magnetic layers such as CoFe or NiFe is often employed to enhance the tunneling magnetoresistance (TMR), although it also locally reduces the magnetization and modifies the magnetic properties. To properly model the magnetic behavior of such structures, it is important to be able to accurately account for these modifications. In this paper we investigate, experimentally and by means of ab initio calculations, the degradation of magnetic and magneto-dynamic properties of Ni0.81Fe0.19 films doped with small amounts of Ta. Both the calculations and the experiment confirm the expected drop of saturation magnetization parameter with increased Ta doping. It is also found that the exchange stiffness is reduced much faster than the magnetization. Calculations show that the presence of Ta impurities has the greatest effect on the magnetic properties of Ni, the dominant element. For example, the introduction of 10 atomic % Ta reduces the exchange stiffness constant by a factor of 10, while the room temperature magnetization reduces by less than a factor of 3, resulting mainly from a decrease in the Curie temperature from 870 to 420 K. Consequently, the reduction in exchange coupling across Ta nanolayers can significantly modify the detailed magnetic behavior and in particular the propagation of exchange coupling within MTJ multilayers.

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Optimization of perpendicular anisotropy of Ta-inserted double CoFeB/MgO interface MTJ’s for STT-MRAM

Cited by 7 publications

References 12 publications

[Co/Ni] multilayers with robust post-annealing performance for spintronics device applications

[Co/Ni] multilayers with robust post-annealing performance for spintronics device applications

Review on magnetic/nonmagnetic heterojunction interface effects on spintronic MTJ devices

Exchange stiffness reduction in Ta substituted NiFe alloys

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