Spin transfer torque ferromagnetic resonance induced spin pumping in the Fe/Pd bilayer system

Kumar, Ankit; Akansel, Serkan; Stopfel, Henry; Fazlali, Masoumeh; Åkerman, Johan; Bručas, Rimantas; Svedlindh, Peter

doi:10.1103/physrevb.95.064406

Cited by 44 publications

(41 citation statements)

References 22 publications

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“…The I RF -induced torque acting on the Py layer generates a sustained precession of the magnetization, which mixes with the anisotropic magnetoresistance and spin Hall magnetoresistance creating a dc-mixing voltage V mix . This rectified mixing voltage provides the information on the material parameters and torques acting on the magnetization, which is written as 32 V mix = V 0 ( Sfs + Afa ). Here, V 0 is the amplitude of the mixing voltage, and fs and fa are symmetric and antisymmetric Lorentzian functions, respectively.…”

Section: Resultsmentioning

confidence: 99%

Large Damping-Like Spin–Orbit Torque in a 2D Conductive 1T-TaS₂ Monolayer

et al. 2020

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A damping-like spin-orbit torque (SOT) is a prerequisite for ultralow-power spin logic devices. Here, we report on the damping-like SOT in just one monolayer of the conducting transition-metal dichalcogenide (TMD) TaS 2 interfaced with a NiFe (Py) ferromagnetic layer. The charge-spin conversion efficiency is found to be 0.25 ± 0.03 in TaS 2 (0.88)/Py(7), and the spin Hall conductivity is found to be superior to values reported for other TMDs. We also observed sizable field-like torque in this heterostructure. The origin of this large damping-like SOT can be found in the interfacial properties of the TaS 2 /Py heterostructure, and the experimental findings are complemented by the results from density functional theory calculations. It is envisioned that the interplay between interfacial spin–orbit coupling and crystal symmetry yielding large damping-like SOT. The dominance of damping-like torque demonstrated in our study provides a promising path for designing the next-generation conducting TMD-based low-powered quantum memory devices.

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Section: Resultsmentioning

confidence: 99%

Large Damping-Like Spin–Orbit Torque in a 2D Conductive 1T-TaS₂ Monolayer

et al. 2020

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“…Thus, we have fitted our results with Eq. 6, where we determined the intrinsic spin-mixing conductance ( G ↑↓ ) = (7.22 ± 0.05) × 10 14 cm −2 ( 36 , 37 ). Subsequently, we obtained the spin diffusion length (λ) of Ta to be 2.44 ± 0.16 nm as a fitting parameter, which is very close to the literature value ( 23 ).…”

Section: Resultsmentioning

confidence: 99%

“…S4. For energy-efficient applications of spin current in multilayered devices, large interface transparency ( T ) is required, and this primarily becomes associated with G eff ( t ) ( 37 ). After determining the resistivity of these heterostructures and G eff experimentally, we have found the value of T as 0.50 ± 0.03 using Eq.…”

Section: Resultsmentioning

confidence: 99%

All-optical detection of interfacial spin transparency from spin pumping in β-Ta/CoFeB thin films

et al. 2019

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Generation and utilization of pure spin current have revolutionized energy-efficient spintronic devices. Spin pumping effect generates pure spin current, and for its increased efficiency, spin-mixing conductance and interfacial spin transparency are imperative. The plethora of reports available on generation of spin current with giant magnitude overlook the interfacial spin transparency. Here, we investigate spin pumping in β-Ta/CoFeB thin films by an all-optical time-resolved magneto-optical Kerr effect technique. From variation of Gilbert damping with Ta and CoFeB thicknesses, we extract the spin diffusion length of β-Ta and spin-mixing conductances. Consequently, interfacial spin transparency is derived as 0.50 ± 0.03 from the spin Hall magnetoresistance model for the β-Ta/CoFeB interface. Furthermore, invariance of Gilbert damping with Cu spacer layer thickness inserted between β-Ta and CoFeB layers confirms the absence of other interface effects including spin memory loss. This demonstrates a reliable and noninvasive way to determine interfacial spin transparency and signifies its role in generation of pure spin current by spin pumping effect.

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“…[ 20 ] Note that spin‐pumping generates symmetric signals with the same angular dependence as the V S from damping‐like torque in ST‐FMR, [ 25 ] but such contribution is negligible (see supporting material). [ 43,44 ] The SOT efficiency ξ SOT can be expressed as

ξ_{SOT} = (V_{S}^{0} / V_{A}^{0}) (\frac{e μ_{0} M_{s} t d}{ℏ}) {([], 1 + (4 π M_{eff} / H_{ext}))}^{1 / 2}

…”

Section: Figurementioning

confidence: 99%

High Spin Hall Conductivity in Large‐Area Type‐II Dirac Semimetal PtTe₂

et al. 2020

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Spin-orbit torque (SOT) provides an ultrafast and energy-efficient means to switch magnetization, which is of fundamental and technical importance for spintronic devices. [1][2][3][4][5] A typical SOT device consists of heavy metal/ferromagnet (HM/FM) bilayer, where the HM (e.g., Pt, W, Ta, etc.) converts charge current into spin current mainly due to the spin Hall effect (SHE) and then exerts a torque on the adjacent FM enabling magnetization manipulation. To improve the energy efficiency of SOT-driven magnetization switching, considerable efforts have been made to enhance the charge-spin conversion efficiency of HM [6][7][8][9] and reduce the shunting current in the FM. [10,11] Engineering the bilayer structure [9,12] or replacing HM by novel materials with larger charge-spin conversion efficiency and higher conductivity [10,13,14] are possible avenues to realize higher SOT efficiency. Manipulation of magnetization by electric-current-induced spin-orbit torque (SOT) is of great importance for spintronic applications because of its merits in energy-efficient and high-speed operation. An ideal material for SOT applications should possess high charge-spin conversion efficiency and high electrical conductivity. Recently, transition metal dichalcogenides (TMDs) emerge as intriguing platforms for SOT study because of their controllability in spin-orbit coupling, conductivity, and energy band topology. Although TMDs show great potentials in SOT applications, the present study is restricted to the mechanically exfoliated samples with small sizes and relatively low conductivities.Here, a manufacturable recipe is developed to fabricate large-area thin films of PtTe 2 , a type-II Dirac semimetal, to study their capability of generating SOT. Large SOT efficiency together with high conductivity results in a giant spin Hall conductivity of PtTe 2 thin films, which is the largest value among the presently reported TMDs. It is further demonstrated that the SOT from PtTe 2 layer can switch a perpendicularly magnetized CoTb layer efficiently. This work paves the way for employing PtTe 2 -like TMDs for wafer-scale spintronic device applications.

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Spin transfer torque ferromagnetic resonance induced spin pumping in the Fe/Pd bilayer system

Cited by 44 publications

References 22 publications

Large Damping-Like Spin–Orbit Torque in a 2D Conductive 1T-TaS₂ Monolayer

Large Damping-Like Spin–Orbit Torque in a 2D Conductive 1T-TaS₂ Monolayer

All-optical detection of interfacial spin transparency from spin pumping in β-Ta/CoFeB thin films

High Spin Hall Conductivity in Large‐Area Type‐II Dirac Semimetal PtTe₂

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Spin transfer torque ferromagnetic resonance induced spin pumping in the Fe/Pd bilayer system

Cited by 44 publications

References 22 publications

Large Damping-Like Spin–Orbit Torque in a 2D Conductive 1T-TaS2 Monolayer

Large Damping-Like Spin–Orbit Torque in a 2D Conductive 1T-TaS2 Monolayer

All-optical detection of interfacial spin transparency from spin pumping in β-Ta/CoFeB thin films

High Spin Hall Conductivity in Large‐Area Type‐II Dirac Semimetal PtTe2

Contact Info

Product

Resources

About

Large Damping-Like Spin–Orbit Torque in a 2D Conductive 1T-TaS₂ Monolayer

Large Damping-Like Spin–Orbit Torque in a 2D Conductive 1T-TaS₂ Monolayer

High Spin Hall Conductivity in Large‐Area Type‐II Dirac Semimetal PtTe₂