Quantification of the spin-Hall anti-damping torque with a resonance spectrometer

Emori, Satoru; Nan, Tianxiang; Oxholm, Trevor M.; Boone, Carl; Jones, John G.; Howe, Brandon M.; Brown, Gail J.; Budil, David E.; Sun, Nian X.

doi:10.1063/1.4906062

Cited by 16 publications

(16 citation statements)

References 43 publications

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“…This effect was first predicted by Dyakonov and Perel 3 , where due to spin-orbit interaction 18 an electrical current results in transverse flow of spins with polarisation perpendicular to both the charge and spin current directions 19 . The SHE was demonstrated using a number of techniques, including field-swept ferromagnetic resonance (FMR) 20 , 21 , spin torque FMR 22 – 24 , optical FMR 25 , time-resolved optical techniques 26 and electrical methods 27 . The SHE-generated spin polarisation results in a torque when injected in a ferromagnetic layer, which makes this effect very important for magnetic devices, resulting in motion of domain walls 28 with important applications to synthetic antiferromagnetic domain wall devices 29 , 30 .…”

Section: Introductionmentioning

confidence: 99%

Unified treatment of spin torques using a coupled magnetisation dynamics and three-dimensional spin current solver

Lepadatu

2017

Sci Rep

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A three-dimensional spin current solver based on a generalised spin drift-diffusion description, including the bulk and interfacial spin Hall effects, is integrated with a magnetisation dynamics solver. The resulting model is shown to simultaneously reproduce the spin-orbit torques generated using the spin Hall effect, spin pumping torques generated by magnetisation dynamics in multilayers, as well as the spin transfer torques acting on magnetisation regions with spatial gradients, whilst field-like and spin-like torques are reproduced in a spin valve geometry. Two approaches to modelling interfaces are analysed, one based on the spin mixing conductance and the other based on continuity of spin currents where the spin dephasing length governs the absorption of transverse spin components. In both cases analytical formulas are derived for the spin-orbit torques in a heavy metal/ferromagnet bilayer geometry, showing in general both field-like and damping-like torques are generated. The limitations of the analytical approach are discussed, showing that even in a simple bilayer geometry, due to the non-uniformity of the spin currents, a full three-dimensional treatment is required. The model is further applied to the analysis of the spin Hall angle in Pt by reproducing published experimental ferromagnetic resonance data in the bilayer geometry.

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Section: Introductionmentioning

confidence: 99%

Unified treatment of spin torques using a coupled magnetisation dynamics and three-dimensional spin current solver

Lepadatu

2017

Sci Rep

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“…A high-impedance current source outputs I dc , and we restrict |I dc | ≤ 2 mA (equivalent to the current density in Pt |J c,P t | < 10 11 A/m 2 ) to minimize Joule heating and nonlinear dynamics. The dependence of the resonance linewidth W on I dc allows for quantification of the damping-like torque 48,[54][55][56][57][58][59][60] , while the change in the resonance field H F MR yields a direct measure of the field-like torque 52 . Thus, dc-tuned ST-FMR quantifies both spinorbit torque contributions.…”

Section: B Spin-torque Ferromagnetic Resonancementioning

confidence: 99%

“…60. These NiFe/(Cu/)Pt strips were fabricated on the same substrate as the ST-FMR device sets described in Sec.…”

Section: Electrical Detection Of Spin Pumpingmentioning

confidence: 99%

Comparison of spin-orbit torques and spin pumping across NiFe/Pt and NiFe/Cu/Pt interfaces

et al. 2015

Self Cite

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We experimentally investigate spin-orbit torques and spin pumping in NiFe/Pt bilayers with direct and interrupted interfaces. The damping-like and field-like torques are simultaneously measured with spin-torque ferromagnetic resonance tuned by a dc bias current, whereas spin pumping is measured electrically through the inverse spin Hall effect using a microwave cavity. Insertion of an atomically thin Cu dusting layer at the interface reduces the damping-like torque, field-like torque, and spin pumping by nearly the same factor of ≈1.4. This finding confirms that the observed spin-orbit torques predominantly arise from diffusive transport of spin current generated by the spin Hall effect. We also find that spin-current scattering at the NiFe/Pt interface contributes to additional enhancement in magnetization damping that is distinct from spin pumping.

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“…There have been many other techniques developed over the last decade, although are less popular but utilize interesting phenomena in probing SOTs or estimating the charge-spin conversion efficiency. Notable among them are the SHE tunneling spectroscopy proposed by Liu et al, 79 resonance spectroscopy by Emori et al, 80 longitudinal magneto-optic Kerr effect (MOKE) method by Fan et al, 36 SHE-driven chiral domain wall motion technique by Emori et al, 66 and thermal injection method by Qu et al 81 As a final remark, we address the challenges that these existing quantification techniques might face while the systems-of-interests are heterostructures with emergent materials such as TIs, TMDs, and Weyl semimetals. First of all, unlike conventional metallic SH layers, these exotic materials, such as Bi2Se3, 37,[82][83][84] (Bi0.5Sb0.5)2Te3, 85,86 WTe2, 87,88 and MoTe2 [89][90][91] are typically highly resistive (𝜌 SH > 10 2 μΩ-cm).…”

Section: Discussionmentioning

confidence: 99%

Spin–orbit torque characterization in a nutshell

Nguyen¹,

Pai

2021

APL Materials

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Spin current and spin torque generation through the spin-orbit interactions in solids, of bulk or interfacial origin, are at the heart of spintronics research. The realization of spin-orbit torque (SOT) driven magnetic dynamics and switching in diverse magnetic heterostructures also paves the way for developing SOT magnetoresistive random access memory (SOT-MRAM) and other novel SOT memory and logic devices. Of scientific and technological importance are accurate and efficient SOT quantification techniques which have been abundantly developed in the last decade. In this article, we summarize popular techniques to experimentally quantify SOTs in magnetic heterostructures at micro-as well as nano-scale. For each technique, we give an overview of its principle, variations, strengths, shortcomings, error sources and any cautions in usage. Finally, we discuss the remaining challenges in understanding and quantifying the SOTs in heterostructures.I.

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Quantification of the spin-Hall anti-damping torque with a resonance spectrometer

Cited by 16 publications

References 43 publications

Unified treatment of spin torques using a coupled magnetisation dynamics and three-dimensional spin current solver

Unified treatment of spin torques using a coupled magnetisation dynamics and three-dimensional spin current solver

Comparison of spin-orbit torques and spin pumping across NiFe/Pt and NiFe/Cu/Pt interfaces

Spin–orbit torque characterization in a nutshell

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