Effect of Ru thickness on spin pumping in Ru/Py bilayer

Behera, Nilamani; Singh, M. Sanjoy; Chaudhary, Sujeet; Pandya, Dinesh K.; Muduli, P. K.

doi:10.1063/1.4913510

Cited by 21 publications

(13 citation statements)

References 36 publications

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“…6 and in Table II. In our studied films, the thickness of the Ru layer, t N Ru (=3 nm) is less than the spin diffusion length λ sd Ru (=15 nm) [32]. Therefore, significant back flow of the spin angular momentum from the Ru layer to the FeCo layer is expected.…”

Section: B Op-fmrmentioning

confidence: 85%

Engineering of spin mixing conductance at Ru/FeCo/Ru interfaces: Effect of Re doping

et al. 2020

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We have deposited polycrystalline Re doped (F e65Co35)100−xRex (0 ≤ x ≤ 12.6 at%) thin films grown under identical conditions and sandwiched between thin layers of Ru in order to study the phenomenon of spin pumping as a function of Re concentration. In-plane and out-of-plane ferromagnetic resonance spectroscopy results show an enhancement of the Gilbert damping with an increase in Re doping. We found evidence of an increase in the real part of effective spin mixing conductance [Re(g ↑↓ ef f )] with the increase in Re doping of 6.6 at%, while a decrease is evident at higher Re doping. The increase in Re(g ↑↓ ef f ) can be linked to the Re doping induced change of the interface electronic structure in the non-magnetic Ru layer and the effect interfacial spin-orbit coupling has on the effective spin-mixing conductance. The lowest and highest values of Re(g ↑↓ ef f ) are found to be 9.883(02) nm −2 and 19.697(02) nm −2 for 0 at% and 6.6 at% Re doping, respectively. The saturation magnetization decreases with increasing Re doping, from 2.362(13) T for the undoped film to 1.740(03) T for 12.6 at% Re doping. This study opens a new direction of tuning the spin-mixing conductance in magnetic heterostructures by doping of the ferromagnetic layer, which is essential for the realization of energy efficient operation of spintronic devices.

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Section: B Op-fmrmentioning

confidence: 85%

Engineering of spin mixing conductance at Ru/FeCo/Ru interfaces: Effect of Re doping

et al. 2020

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“…Transition metals such as Ru and Pt are particularly useful for enhancing damping in FM/NM systems via spin pumping mechanisms [17,32], for control of perpendicular magnetic anisotropy (PMA) [33,34], and for enhancing spin-orbit torques when used in combination [35]. For these materials it is expected that spin relaxation follows the mechanisms outlined by the Elliot-Yafet (EY) theory [36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Spin transport across the interface in ferromagnetic/nonmagnetic systems

et al. 2019

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Understanding interfacial spin transport is key to developing magnetoelectonic devices, however, the exact nature of the parameters involved is unclear. Here, we report a detailed ferromagnetic resonance-based spintransport analysis on a variety of structures of both ferromagnetic (Co, CoFeB) and heavy metal layers (Pt, Ru) in order to fully quantify the interfacial spin-transport parameters. Enhanced spin-mixing conductance is observed for more closely matched ferromagnet and heavy metal crystal structures, and, significantly, the inclusion of a thickness-dependent spin-diffusion length gives a bulk value of 9.4 ± 0.7 nm for Pt, resolving reported discrepancies.

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“…The interfacial spin mixing conductance for Ni 79 Fe 21 /Ru, was found in Ref. 16 to beg F N ↑↓ = 24 nm −2 . For a F/N/F structure, in the limit of ballistic transport with no spin relaxation through N , the effective spin mixing conductance isg F N ↑↓ /2: spin current must cross two interfaces to relax in the opposite F layer, and the conductance reflects two series resistances 17 .…”

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Large spin pumping effect in antisymmetric precession of Ni79Fe21/Ru/Ni79Fe21

Yang

Bailey

2016

Applied Physics Letters

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In magnetic trilayer structures, a contribution to the Gilbert damping of ferromagnetic resonance arises from spin currents pumped from one layer to another. This contribution has been demonstrated for layers with weakly coupled, separated resonances, where magnetization dynamics are excited predominantly in one layer and the other layer acts as a spin sink. Here we show that trilayer structures in which magnetizations are excited simultaneously, antisymmetrically, show a spin-pumping effect roughly twice as large. The antisymmetric (optical) mode of antiferromagnetically coupled Ni 79 Fe 21 (8nm)/Ru/Ni 79 Fe 21 (8nm) trilayers shows a Gilbert damping constant greater than that of the symmetric (acoustic) mode by an amount as large as the intrinsic damping of Py (∆α 0.006). The effect is shown equally in field-normal and field-parallel to film plane geometries over 3-25 GHz. The results confirm a prediction of the spin pumping model and have implications for the use of synthetic antiferromagnets (SAF)-structures in GHz devices.Pumped spin currents 1,2 are widely understood to influence the magnetization dynamics of ultrathin films and heterostructures. These spin currents increase the Gilbert damping or decrease the relaxation time for thin ferromagnets at GHz frequencies. The size of the effect has been parametrized through the effective spin mixing conductance g ↑↓ r , which relates the spin current pumped out of the ferromagnet, transverse to its static (timeaveraged) magnetization, to its precessional amplitude and frequency. The spin mixing conductance is interesting also because it determines the transport of pure spin current across interfaces in quasistatic spin transport, manifested in e.g. the spin Hall effect.In the spin pumping effect, spin current is pumped away from a ferromagnet / normal metal (F 1 /N) interface, through precession of F 1 , and is absorbed elsewhere in the structure, causing angular momentum loss and damping of F 1 . The spin current can be absorbed through different processes in different materials. When injected into paramagnetic metals (Pt, Pd, Ru, and others), the spin current relaxes exponentially with paramagnetic layer thickness 3-5 . The relaxation process has been likened to spin-flip scattering as measured in CPP-GMR, where spin-flip events are localized to heavy-metal impurities 6 and the measurement reveals the spin diffusion length λ SD . When injected into other ferromagnets (F 2 in F 1 /N/F 2 ), the spin current is absorbed through its torque on magnetization 5,7 . A similar process appears to be relevant for antiferromagnets as well 8 .In F 1 /N/F 2 structures, only half of the total possible spin pumping effect has been detected up until now. For well-separated resonances of F 1 and F 2 , only one layer will precess with large amplitude at a given frequency ω, and spin current is pumped from a precessing F 1 into a static F 2 . If both layers precess symmetrically, with a) Electronic mail: Contact author. web54@columbia.edu the same amplitude and phase, equal and ...

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Effect of Ru thickness on spin pumping in Ru/Py bilayer

Cited by 21 publications

References 36 publications

Engineering of spin mixing conductance at Ru/FeCo/Ru interfaces: Effect of Re doping

Engineering of spin mixing conductance at Ru/FeCo/Ru interfaces: Effect of Re doping

Spin transport across the interface in ferromagnetic/nonmagnetic systems

Large spin pumping effect in antisymmetric precession of Ni79Fe21/Ru/Ni79Fe21

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