Tunable Magnetization Dynamics in Interfacially Modified Ni81Fe19/Pt Bilayer Thin Film Microstructures

Ganguly, Arnab; Azzawi, S.; Saha, Susmita; King, J. A.; Rowan-Robinson, Richard M.; Hindmarch, A. T.; Sinha, Jaivardhan; Atkinson, D.; Barman, Anjan

doi:10.1038/srep17596

Cited by 45 publications

(34 citation statements)

References 41 publications

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“…2(a) and 2(c) with three characteristic regions can be understood by considering several intrinsic and extrinsic effects occurring at the interface of the FM and NM layers. It is known that d-d hybridization, spin-pumping, and two-magnon scattering are the effective factors for damping enhancement in FM/NM thin films [3,4,11,13,17,21,23]. The experimental results are in agreement with a recent theoretical study [3] where damping increases with increasing Pt capping layer thickness up to a broad peak followed by a decrease to constant value with further increases in thickness.…”

Section: Discussionsupporting

confidence: 87%

“…Understanding and controlling damping in thin film systems therefore continues to drive research in this field. It has been demonstrated that damping can be enhanced in both bulk ferromagnetic (FM) [1][2][3][4] and multilayered systems [5][6][7][8] and many studies have addressed the fundamental origin of damping both experimentally and theoretically [1,3,[9][10][11][12][13][14][15]. Both Co and Ni 81 Fe 19 have attracted a lot of attention due to their common application in magnetic devices.…”

Section: Introductionmentioning

confidence: 99%

“…This can occur when the symmetry of the system is disturbed by structural defects like film roughness and intermixing [1,3,21] and will enhance the effective damping of the magnetization precession. Increased intermixing will also enhance the effective spin-mixing conductance [8,21,22], and modifying the interface will affect all of the mechanisms mentioned above [4,23]. It is therefore of great interest to study the evolution of precessional magnetic damping in FM/NM bilayers as the interface develops as a function of the NM thickness.…”

Section: Introductionmentioning

confidence: 99%

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Evolution of damping in ferromagnetic/nonmagnetic thin film bilayers as a function of nonmagnetic layer thickness

et al. 2016

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Reprinted with permission from the American Physical Society: Azzawi, S. and Ganguly, A. and Toka c, M. and Rowan-Robinson, R.M. and Sinha, J. and Hindmarch, A.T. and Barman, A. and Atkinson, D. (2016) 'Evolution of damping in ferromagnetic/nonmagnetic thin lm bilayers as a function of nonmagnetic layer thickness.', Physical review B., 93 (5). 054402 c 2016 by the American Physical Society. Readers may view, browse, and/or download material for temporary copying purposes only, provided these uses are for noncommercial personal purposes. Except as provided by law, this material may not be further reproduced, distributed, transmitted, modied, adapted, performed, displayed, published, or sold in whole or part, without prior written permission from the American Physical Society.Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. The evolution of damping in Co/Pt, Co/Au, and Ni 81 Fe 19 /Pt bilayers was studied with increasing nonmagnetic (NM) heavy-metal layer thicknesses in the range 0.2 nm t NM 10 nm, where t NM is the NM layer thickness. Magnetization precession was measured in the time domain using time-resolved magneto-optical Kerr effect magnetometry. Fitting of the data with a damped sinusoidal function was undertaken in order to extract the phenomenological Gilbert damping coefficient α. For Pt-capped Co and Ni 81 Fe 19 layers a large and complex dependence of α on the Pt layer thickness was observed, while for Au capping no significant dependence was observed. It is suggested that this difference is related to the different localized spin-orbit interaction related to intermixing and to d-d hybridization of Pt and Au at the interface with Co or Ni 81 Fe 19 . Also it was shown that damping is affected by the crystal structure differences in FM thin films and at the interface, which can modify the spin-diffusion length and the effective spin-mixing conductance. In addition to the intrinsic damping an extrinsic contribution plays an important role in the enhancement of damping when the Pt capping layer is discontinuous. The dependence of damping on the nonmagnetic layer thickness is complex but shows qualitative agreement with recent theoretical predictions.

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Section: Discussionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evolution of damping in ferromagnetic/nonmagnetic thin film bilayers as a function of nonmagnetic layer thickness

et al. 2016

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“…The discrepancies between the previous studies may be associated with the details of the multilayered structure. In particular, the nature of the interface structure in such systems is known to be important for spin-pumping 17,18 and in the ultra-thin film regime the presence of a continuous intermediate layer needs to be established when studying such interlayer effects 19 . Spin pumping and d − d hybridization across a FM/NM interface both lead to additional magnetic energy loss and increased precessional damping.…”

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confidence: 99%

Spin current propagation through ultra-thin insulating layers in multilayered ferromagnetic systems

Swindells

Hindmarch

Gallant

et al. 2020

Applied Physics Letters

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Spin current pumping from a ferromagnet through an insulating layer into a heavy metal was studied in a CoFeB/SiO2/Pt system in relation to the thickness and interfacial structure of the insulating layer. The propagation of spin current from the ferromagnet into the heavy metal falls rapidly with sub-nanometer thicknesses of SiO2 and is suppressed beyond a nominal thickness of 2 nm. Structural analysis shows that SiO2 only forms a complete barrier layer beyond around 2 nm, indicating that the presence of a discontinuous insulating barrier, and not tunneling or diffusion, explains the main observations of spin-pumping with thin insulating layers.

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“…However, the comparison of our results with the experimental data is hindered not only by the different interface/surface orientation in the theoretical structures and the experimental multilayers but also by the fact that the Co/NM interfaces in the experimental (111) fcc Co/Pd and Co/Pt layered systems exhibit significant roughness and strong intermixing [65,71]. Such structure imperfections can lead to enhancement of α as observed in L1 0 FePt films [27] as well as an additional magnetic damping due the two-magnon scattering [40,41,72], which may become particularly significant if the external magnetic field is applied parallel or at a small angle to the film surface. The resulting extra damping terms can account for the difference between the effective Gilbert damping constant measured in experiment and the present theoretical results without resorting to the use of very small scattering rates.…”

Section: -5mentioning

confidence: 95%

Gilbert damping in binary magnetic multilayers

Barati

Cinal

2017

Phys. Rev. B

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We present quantum mechanical calculations of the Gilbert damping constant α in ultrathin L1 0 [Co/NM] N superlattices and (001) fcc [Co/NM] N magnetic multilayers built of cobalt and nonmagnetic metals NM = Cu, Ag, Pd, Pt, and Au. The calculations are performed within a realistic nine-orbital tight-binding model of the band structure including spin-orbit interaction. The dependence of α on the stacking number N , ferromagnetic and nonmagnetic layer thicknesses as well as the electron scattering rate is investigated. The damping constant is shown to be the sum of a constant term (bulklike) and a 1/N term (due to external surfaces) which arise from interand intraband electronic transitions, respectively. The calculated α is found to be enhanced in the considered multilayers in comparison with its values for bulk Co and their bilayer counterparts with the same total Co thickness. The origin of this enhancement and the variation of α with the geometric structure of the multilayers are further investigated by analyzing the damping contributions from individual atomic layers. The obtained theoretical results for the damping constant are shown to be in good agreement with previous experimental observations in magnetic multilayers. In particular, the experimentally observed linear dependence on the ratio of NM (Pd or Pt) and Co layer thicknesses is reproduced in the present calculations.

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Tunable Magnetization Dynamics in Interfacially Modified Ni81Fe19/Pt Bilayer Thin Film Microstructures

Cited by 45 publications

References 41 publications

Evolution of damping in ferromagnetic/nonmagnetic thin film bilayers as a function of nonmagnetic layer thickness

Evolution of damping in ferromagnetic/nonmagnetic thin film bilayers as a function of nonmagnetic layer thickness

Spin current propagation through ultra-thin insulating layers in multilayered ferromagnetic systems

Gilbert damping in binary magnetic multilayers

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