Anomalous spin Hall magnetoresistance in Pt/Co bilayers

Kawaguchi, Masashi; Towa, Daiki; Lau, Yong‐Chang; Takahashi, Saburo; Hayashi, Masamitsu

doi:10.1063/1.5021510

Cited by 43 publications

(30 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The resistivity of each material was determined from the measured sheet conductance G = l/(wR) of each mi-crostripe as a function of t HM , according to the procedure described in Ref. [41]. The resistivity of W was constant for the thicknesses above 2 nm: ρ W = 116 µΩcm, which indicates the existence of the highly-resistive β-phase.…”

Section: Resultsmentioning

confidence: 99%

Determination of Spin Hall Angle in Heavy-Metal/ Co−Fe−B -Based Heterostructures with Interfacial Spin-Orbit Fields

et al. 2019

View full text Add to dashboard Cite

Magnetization dynamics in W/CoFeB, CoFeB/Pt and W/CoFeB/Pt multilayers was investigated using spin-orbit-torque ferromagnetic resonance (SOT-FMR) technique. An analytical model based on magnetization dynamics due to SOT was used to fit heavy metal (HM) thickness dependence of symmetric and antisymmetric components of the SOT-FMR signal. The analysis resulted in a determination of the properties of HM layers, such as spin Hall angle and spin diffusion length. The spin Hall angle of -0.36 and 0.09 has been found in the W/CoFeB and CoFeB/Pt bilayers, respectively, which add up in the case of W/CoFeB/Pt trilayer. More importantly, we have determined effective interfacial spin-orbit fields at both W/CoFeB and CoFeB/Pt interfaces, which are shown to cancel Oersted field for particular thicknesses of the heavy metal layers, leading to pure spin-current-induced dynamics and indicating the possibility for a more efficient magnetization switching.

show abstract

Section: Resultsmentioning

confidence: 99%

Determination of Spin Hall Angle in Heavy-Metal/ Co−Fe−B -Based Heterostructures with Interfacial Spin-Orbit Fields

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The resistivity of Co and Pt layers were determined in Pt and Co wedge sample, as described in Ref. [25]. The Pt resistivity was almost constant ρ Pt ≈ 23 µΩcm whereas, the Co resistivity, ρ Co , varied from 15 to 29 µΩcm with decreasing thickness -detailed information are presented in Supplemental Material.…”

Section: Methodsmentioning

confidence: 99%

Field-Free Spin-Orbit-Torque Switching in Co / Pt / Co Multilayer with Mixed Magnetic Anisotropies

et al. 2019

View full text Add to dashboard Cite

Spin-orbit-torque (SOT) induced magnetization switching in Co/Pt/Co trilayer, with two Co layers exhibiting magnetization easy axes orthogonal to each other is investigated. Pt layer is used as a source of spin-polarized current as it is characterized by relatively high spin-orbit coupling. The spin Hall angle of Pt, θ = 0.08 is quantitatively determined using spin-orbit torque ferromagnetic resonance technique. In addition, Pt serves as a spacer between two Co layers and depending on it's thickness, different interlayer exchange coupling (IEC) energy between ferromagnets is induced. Intermediate IEC energies, resulting in a top Co magnetization tilted from the perpendicular direction, allows for SOT-induced field-free switching of the top Co layer. The switching process is discussed in more detail, showing the potential of the system for neuromorphic applications.

show abstract

“…The growth of ∆g yz /g at small thicknesses [41,42] is the main evidence in favor of the spin-Hall theory of magnetoresistance in FM/HM bilayers. However, this inference assumes that the interface is well-formed and has the same properties for all d N .…”

mentioning

confidence: 96%

Interfacial contributions to spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers

2020

View full text Add to dashboard Cite

The thickness dependence of spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers is studied using the first-principles non-equilibrium Green's function formalism combined with the Anderson disorder model. A systematic expansion in orthogonal vector spherical harmonics is used for the angular dependence of the torque. The damping-like torque in Co/Pt and Co/Au bilayers can be described as a sum of the spin-Hall contribution, which increases with thickness in agreement with the spin-diffusion model, and a comparable interfacial contribution. The magnetoconductance in the plane perpendicular to the current in Co/Pt bilayers is of the order of a conductance quantum per interfacial atom, exceeding the prediction of the spin-Hall model by more than an order of magnitude. This suggests that the "spin-Hall magnetoresistance," similarly to the damping-like torque, has a large interfacial contribution unrelated to the spin-Hall effect. arXiv:1908.02680v2 [cond-mat.mes-hall]

show abstract

Anomalous spin Hall magnetoresistance in Pt/Co bilayers

Cited by 43 publications

References 48 publications

Determination of Spin Hall Angle in Heavy-Metal/ Co−Fe−B -Based Heterostructures with Interfacial Spin-Orbit Fields

Determination of Spin Hall Angle in Heavy-Metal/ Co−Fe−B -Based Heterostructures with Interfacial Spin-Orbit Fields

Field-Free Spin-Orbit-Torque Switching in Co / Pt / Co Multilayer with Mixed Magnetic Anisotropies

Interfacial contributions to spin-orbit torque and magnetoresistance in ferromagnet/heavy-metal bilayers

Contact Info

Product

Resources

About