Disorder Dependence of Interface Spin Memory Loss

Gupta, Kriti; Wesselink, Rien J. H.; Liu, Ruixi; Yuan, Zhe; Kelly, Paul J.

doi:10.1103/physrevlett.124.087702

Cited by 71 publications

(85 citation statements)

References 52 publications

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“…The calculated AR products and δ parameters are in good agreement with experimental measurements [1] in systems without Pd, but both are strongly overestimated for (Au,Ag,Cu,Pd)|Pd interfaces. However, the results for the Au|Pd (111) interface with the spin accumulation parallel to the interface are in good agreement with recent calculations of Gupta et al [47] (AR = 0.81 f m 2 and δ = 0.43) based on the analysis of the local spin currents near the interface.…”

Section: A Nonmagnetic Interfacessupporting

confidence: 91%

“…For Pt|Co the results for AR and δ are in good agreement both with experiment and with calculations using the discontinuity of the spin current. [47] In other systems AR agrees very well with experiment but δ is underestimated, which may be due to the neglect of interfacial disorder and to the limitations of the adiabatic-embedding method.…”

Section: A Nonmagnetic Interfacesmentioning

confidence: 68%

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Generalized magnetoelectronic circuit theory and spin relaxation at interfaces in magnetic multilayers

2020

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Spin transport at metallic interfaces is an essential ingredient of various spintronic device concepts, such as giant magnetoresistance, spin-transfer torque, and spin pumping. Spin-orbit coupling plays an important role in many such devices. In particular, spin current is partially absorbed at the interface due to spin-orbit coupling. We develop a general magnetoelectronic circuit theory and generalize the concept of spin-mixing conductance, accounting for various mechanisms responsible for spin-flip scattering. For the special case when exchange interactions dominate, we give a simple expression for the spin-mixing conductance in terms of the contributions responsible for spin relaxation (i.e., spin memory loss), spin torque, and spin precession. The spin memory loss parameter δ is related to spin-flip transmission and reflection probabilities. There is no straightforward relation between spin torque and spin memory loss. We calculate the spin-flip scattering rates for N|N, F|N, and F|F interfaces using the Landauer-Büttiker method within the linear muffin-tin orbital method and determine the values of δ using circuit theory.

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Section: A Nonmagnetic Interfacessupporting

confidence: 91%

Section: A Nonmagnetic Interfacesmentioning

confidence: 68%

Generalized magnetoelectronic circuit theory and spin relaxation at interfaces in magnetic multilayers

2020

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“…The critical problem in the field of SO torquesunderstanding of competing microscopic mechanisms behind these components, especially the DL one, and control of their magnitude and ratio-remains unresolved. For example, experiments on FM/heavy-metal bilayers suggest [7] that DL SO torque is primarily generated by the spin Hall current [14] from the bulk of a heavy metal, while interfacial SO coupling (SOC) is detrimental because it generates spin memory loss [15][16][17] and therefore reduction of spin Hall current. Conversely, first-principles quantum transport calculations [18,19] on FM/heavy-metal bilayers find that interfacial SOC and applied over a smaller "active region" are assumed to control the Fermi energy and the local on-site potential in graphene, respectively.…”

Section: Introductionmentioning

confidence: 99%

Scattering-induced and highly tunable by gate damping-like spin-orbit torque in graphene doubly proximitized by two-dimensional magnet Cr2Ge2Te6 and monolayer
Zollner
¹
,
Petrović
²
,
Dolui
³

et al. 2020
Phys. Rev. Research

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Graphene sandwiched between semiconducting monolayers of ferromagnet Cr 2 Ge 2 Te 6 and transition-metal dichalcogenide WS 2 acquires both spin-orbit (SO) coupling, of valley-Zeeman and Rashba types, and exchange coupling. Using first principles combined with quantum transport calculations, we predict that such doubly proximitized graphene within van der Waals heterostructure will exhibit SO torque driven by unpolarized charge current. This system lacks spin Hall current which is putatively considered as necessary for the efficient damping-like (DL) SO torque that plays a key role in magnetization switching. Instead, it demonstrates how a DL SO torque component can be generated solely by skew scattering off spin-independent potential barrier or impurities in purely two-dimensional electronic transport due to the presence of proximity SO coupling and its spin texture tilted out of plane. This leads to current-driven nonequilibrium spin density emerging in all spatial directions, whose cross product with proximity magnetization yields DL SO torque, unlike the ballistic regime with no scatterers in which only field-like (FL) SO torque appears. In contrast to SO torque on conventional metallic ferromagnets in contact with three-dimensional SO-coupled materials, the ratio of FL and DL components of SO torque can be tuned by more than an order of magnitude via combined top and back gates.

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“…[ 35 ] This may be due to interfacial spin memory loss (SML) at the FM/Pt interface as the SML depends on the interface mixing/roughness. [ 36 ] The roughness of our CFA/Pt STEs lies in the range of 0.5–1.1 nm. It means that there is still room for improvements with respect to the E THz by reducing the interface roughness of the CFA/Pt STE.…”

Section: Resultsmentioning

confidence: 99%

Co₂FeAl Full Heusler Compound Based Spintronic Terahertz Emitter

Gupta

Husain

Kumar

et al. 2021

Advanced Optical Materials

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To achieve a large terahertz (THz) amplitude from a spintronic THz emitter (STE), materials with 100% spin polarisation such as Co‐based Heusler compounds as ferromagnetic layer are required. However, these compounds are known to loose their half‐metallicity in the ultrathin film regime, as it is difficult to achieve L21 ordering, which has become a bottleneck for the film growth. Here, the successful deposition using room temperature DC sputtering of the L21 and B2 ordered phases of the Co2FeAl full Heusler compound is reported. Co2FeAl is used as ferromagnetic layer together with highly orientated Pt as nonferromagnetic layer in the Co2FeAl/Pt STE, where an MgO (10 nm) seed layer plays an important role to achieve the L21 and B2 ordering of Co2FeAl. The THz generation in the Co2FeAl/Pt STE is presented, which has a bandwidth of 0.2–4 THz. The THz electric field amplitude is optimized with respect to thickness, orientation, and growth parameters using a thickness dependent model considering the optically induced spin current, superdiffusive spin current, inverse spin Hall effect, and the THz attenuation in the layers. This study, based on the full Heusler Co2FeAl compound opens up a plethora of possibilities in STE research involving full Heusler compounds.

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Disorder Dependence of Interface Spin Memory Loss

Cited by 71 publications

References 52 publications

Generalized magnetoelectronic circuit theory and spin relaxation at interfaces in magnetic multilayers

Generalized magnetoelectronic circuit theory and spin relaxation at interfaces in magnetic multilayers

Scattering-induced and highly tunable by gate damping-like spin-orbit torque in graphene doubly proximitized by two-dimensional magnet Cr2Ge2Te6 and monolayer
Zollner
¹
,
Petrović
²
,
Dolui
³

et al. 2020
Phys. Rev. Research

Co₂FeAl Full Heusler Compound Based Spintronic Terahertz Emitter

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Disorder Dependence of Interface Spin Memory Loss

Cited by 71 publications

References 52 publications

Generalized magnetoelectronic circuit theory and spin relaxation at interfaces in magnetic multilayers

Generalized magnetoelectronic circuit theory and spin relaxation at interfaces in magnetic multilayers

Scattering-induced and highly tunable by gate damping-like spin-orbit torque in graphene doubly proximitized by two-dimensional magnet Cr2Ge2Te6 and monolayer Zollner1, Petrović2, Dolui3 et al. 2020Phys. Rev. Research

Co2FeAl Full Heusler Compound Based Spintronic Terahertz Emitter

Contact Info

Product

Resources

About

Scattering-induced and highly tunable by gate damping-like spin-orbit torque in graphene doubly proximitized by two-dimensional magnet Cr2Ge2Te6 and monolayer
Zollner
¹
,
Petrović
²
,
Dolui
³

et al. 2020
Phys. Rev. Research

Co₂FeAl Full Heusler Compound Based Spintronic Terahertz Emitter