Influence of inverse spin Hall effect in spin-torque ferromagnetic resonance measurements

Kondou, Kouta; Sukegawa, Hiroaki; Kasai, S.; Mitani, Seiji; Niimi, Yasuhiro; Otani, Y.

doi:10.7567/apex.9.023002

Cited by 55 publications

(34 citation statements)

References 30 publications

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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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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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“…[http://dx.doi.org/10.1063/1.4971393] Spin-orbit torque (SOT) from the spin Hall effect (SHE) 1,2 has generated considerable interest for manipulating the magnetization in spintronic devices with ultra-low dissipation. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Recent research has demonstrated highly efficient magnetization switching [4][5][6] and magnetic domain wall (DW) motion [21][22][23][24][25][26][27][28][29][30] by current-induced SOT in ferromagnet (FM)/ heavy metal (HM) bilayer films. In order to ensure scalability and thermal stability in device applications, the FM layer in such structures must exhibit perpendicular magnetic anisotropy (PMA).…”

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confidence: 99%

Spin-orbit torques in Ta/TbxCo100-x ferrimagnetic alloy films with bulk perpendicular magnetic anisotropy

Ueda

Mann

Pai

et al. 2016

Applied Physics Letters

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We quantified the bulk perpendicular magnetic anisotropy (PMA) and spin-orbit torques (SOTs) in bilayer Ta/TbxCo100-x ferrimagnetic alloy films with varying Tb concentration. The coercivity increases dramatically with increasing TbxCo100-x thickness and is enhanced by the presence of a Ta underlayer. The Ta underlayer simultaneously serves as a source of SOT due to the spin Hall effect, which we show provides an efficient means to manipulate the magnetization in bulk PMA materials. It is further shown that the sign of the anomalous Hall voltage is different for rare-earth (RE) and transition-metal (TM) dominated alloy compositions, whereas the sign of the SOT effective field remains the same, suggesting that the former is related to the TM sublattice magnetization whereas the latter is related to the net magnetization. Our results suggest that Ta/TbxCo100-x is a potential candidate for spin-orbitronic device applications and give insight into spin transport and SOTs in rare-earth/transition-metal alloys.

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“…2,4,7,22,23,[31][32][33]35 The measurement provides important magnetic parameters such as demagnetization (4pM eff ), the damping constant (a) and h SH . We prepared samples with the structure substrate/Gd (t)/Co (5 nm)/Pt (4 nm) with in-plane anisotropy by dc magnetron sputtering.…”

mentioning

confidence: 99%

“…The spectra in the positive field range were fitted by a sum of symmetric and antisymmetric Lorentzian functions 2,4,7,22,23,[31][32][33]35 to yield the resonance field (H 0 ) and the line width (D). Figure 5(a) shows typical results of f versus H 0 for Co/Pt and Gd (6 nm)/Co/Pt samples fitted by the Kittel fomula, f ¼ 2p…”

mentioning

confidence: 99%

“…9,20 More recently, current-induced control of the magnetization has been achieved by current-induced spin-orbit torques (SOTs) originating from heavy metal layers with strong spin-orbit coupling, from which the resulting effective fields are strong enough to control the magnetization in adjacent ultra-thin ferromagnetic layers. [1][2][3][4][5][6][7]11,[13][14][15][16][17][18][19][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] In the ferromagnet/heavy metal system, SOTs can arise from the interfacial Rashba effect 11,21,24 and the bulk spin Hall effect (SHE), [2][3][4]7,13,16,22,23,27,[29][30][31][32]…”

mentioning

confidence: 99%

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Effect of rare earth metal on the spin-orbit torque in magnetic heterostructures

Ueda

Pai

Tan

et al. 2016

Applied Physics Letters

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We report the effect of the rare earth metal Gd on current-induced spin-orbit torques (SOTs) in perpendicularly magnetized Pt/Co/Gd heterostructures, characterized using harmonic measurements and spin-torque ferromagnetic resonance (ST-FMR). By varying the Gd metal layer thickness from 0 nm to 8 nm, harmonic measurements reveal a significant enhancement of the effective fields generated from the Slonczewski-like and field-like torques. ST-FMR measurements confirm an enhanced effective spin Hall angle and show a corresponding increase in the magnetic damping constant with increasing Gd thickness. These results suggest that Gd plays an active role in generating SOTs in these heterostructures. Our finding may lead to spin-orbitronics device application such as non-volatile magnetic random access memory, based on rare earth metals.

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Influence of inverse spin Hall effect in spin-torque ferromagnetic resonance measurements

Cited by 55 publications

References 30 publications

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

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

Spin-orbit torques in Ta/TbxCo100-x ferrimagnetic alloy films with bulk perpendicular magnetic anisotropy

Effect of rare earth metal on the spin-orbit torque in magnetic heterostructures

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Influence of inverse spin Hall effect in spin-torque ferromagnetic resonance measurements

Cited by 55 publications

References 30 publications

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

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

Spin-orbit torques in Ta/TbxCo100-x ferrimagnetic alloy films with bulk perpendicular magnetic anisotropy

Effect of rare earth metal on the spin-orbit torque in magnetic heterostructures

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

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