Interface-induced phenomena in magnetism

Hellman, F.; Hoffmann, A.; Tserkovnyak, Yaroslav; Beach, Geoffrey S. D.; Fullerton, Eric E.; Leighton, Chris; MacDonald, Allan H.; Ralph, Daniel; Arena, D. A.; Dürr, H. A.; Fischer, Peter; Grollier, Julie; Heremans, Joseph P.; Jungwirth, T.; Kimel, A.V.; Koopmans, B.; Krivorotov, I. N.; May, Steven J.; Petford‐Long, Amanda K.; Rondinelli, James M.; Samarth, N.; Schuller, Iván K.; Slavin, A. N.; Stiles, Mark D.; Tchernyshyov, Oleg; Thiaville, A.; Zink, B. L.

doi:10.1103/revmodphys.89.025006

Cited by 800 publications

(567 citation statements)

References 916 publications

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“…Apart from basic research this subject has also implications in potential devices based on spintronics/spin-orbitronics [1][2][3], spin torque-oscillator [4,5], magnetic random memory devices [6,7], magnonics [6] etc. A fundamental understanding of the exchange interaction and spin-orbital interaction at the interfaces will increase speed, energy efficiency, miniaturization of size and its multi-functional utilization [8]. Pure spin current is produced by asymmetric scattering of the two electrons with opposite spin angular momentum in the presence of spin orbit coupling at the interface which is known as spin Hall effect [1,3,9,10].…”

Section: Introductionmentioning

confidence: 99%

Study of spin pumping in Co thin film vis-à-vis seed and capping layers using ferromagnetic resonance spectroscopy

Singh

Jena

2017

J. Phys. D: Appl. Phys.

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Abstract:We investigated the dependence of the seed (Ta/Pt, Ta/Au) and capping (Pt/Ta, Au/Ta) layers on spin pumping effect in the ferromagnetic 3 nm thick Co thin film using ferromagnetic resonance spectroscopy. The data is fitted with Kittel's equation to evaluate damping constant and g-factor. A strong dependence of seed and capping layers on spin pumping has been discussed. The value of damping constant (α) is found to be relatively large i.e. 0.0326±0.0008 for the Ta(3)/Pt(3)/Co(3)/Pt(3)/Ta(3) (nm) multilayer structure, while it is 0.0104±0.0003 for Ta(3)/Co(3)/Ta(3) (nm). Increase in α is observed due to Pt layer that works as a good sink for spins due to high spin orbit coupling. In addition, we measured the effective spin conductance  g = 2.00 ± 0.08 × 10 18 m -2 for the tri-layer structure Pt(3)/Co(3)/Pt(3) (nm) as a result of the enhancement in α relative to its bulk value.We observed that the evaluated g-factor decreases as effective demagnetizing magnetic field increases in all the studied samples. The azimuthal dependence of magnetic resonance field and line width showed relatively high anisotropy in the tri-layer Ta(3)/Co(3)/Ta(3) (nm) structure.

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Section: Introductionmentioning

confidence: 99%

Study of spin pumping in Co thin film vis-à-vis seed and capping layers using ferromagnetic resonance spectroscopy

Singh

Jena

2017

J. Phys. D: Appl. Phys.

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“…For instance, measurements of spin current generated by SHE are inevitably affected by the spin relaxation at the Pt interfaces, and by its generation via the interfacial Rashba effect [27]. Indeed, the apparent spin Hall angle has been shown to depend on the transparency of the interfaces [23].…”

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confidence: 99%

“…If the spin relaxation is dominated by the extrinsic Elliot-Yafet (EY) mechanism, which originates from spin-flipping associated with momentum scattering in the presence of SOI, then the spinflip time τ sf is expected to be proportional to the momentum scattering time τ p [41]. Another possible spin relaxation mechanism, Dyakonov-Perel (DP) relaxation, is the result of precession around the momentum-dependent spin-orbit field H SO , and has been extensively discussed in the context of Rashba-Dresselhaus effects in materials with broken inversion symmetry [27,[41][42][43][44]. While Pt is inversion-symmetric, non-vanishing H SO , known as the spin Berry curvature, is allowed by symmetry, and can contribute to both spin relaxation and the intrinsic SHE [26,[45][46][47][48].…”

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confidence: 99%

Evidence for Dyakonov-Perel-like Spin Relaxation in Pt

et al. 2018

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We utilize nanoscale spin valves with Pt spacer layers to characterize spin scattering in Pt. Analysis of the spin lifetime determined from our measurements indicates that the extrinsic Elliot-Yafet spin scattering is dominant at room temperature, while the intrinsic Dyakonov-Perel mechanism dominates at cryogenic temperatures. The significance of the latter is supported by the suppression of spin relaxation in Pt layers interfaced with a ferromagnet, likely caused by the competition between the effective exchange and spin-orbit fields.The interplay between electron's motion and its spin due to the spin-orbit interaction (SOI) opens unprecedented opportunities for the control of both spin and orbital degrees of freedom [1][2][3][4][5]. For instance, the spin Hall effect (SHE) results in generation of pure spin current flowing transverse to charge current [6], enabling electronic control of static and dynamic states of magnetization in metallic and insulating nanomagnets [7][8][9]. Extensive recent studies of materials that exhibit large SOI, including Pt, Ta, W, topological insulators, and alloys such as CuBi, have focused on identifying the intrinsic and extrinsic mechanisms controlling SOI, and characterizing the relevant parameters including the spin-orbit scattering rates, the spin Hall angle, and the effective spin-orbit field [10][11][12][13][14][15][16][17]. Another relevant parameter is the spin diffusion length λ, defined as the length scale over which the spin polarization relaxes away from the external source, which is determined mostly by the spin scattering due to SOI. It is also the length scale for spin current generation via the SHE, and is thus directly related to material's performance in spin-Hall applications.Pt is one of the most extensively studied spin-orbit materials, thanks to the large SOI effects [10,18,19], relatively low resistivity that minimizes Joule heating and current shunting in heterostructures, and low reactivity. A variety of approaches have been utilized to determine the parameters relevant to SOI in Pt such as the spin Hall angle and λ [10,14,18,[20][21][22]. Nevertheless, the values and the mechanisms controlling these parameters are still debated. In particular, the reported values of the spin Hall angle in Pt range from 0.004 to over 0.1 [10,14,23], and those of λ range from less than 1 nm to over 10 nm [10,14,18,[20][21][22][24][25][26]. Such a large spread of the reported characteristics makes it challenging to establish the dominant contributions to spin-orbit effects and the mechanisms controlling them.One of the main difficulties in analyzing SOI is posed by the interplay between the interfacial and bulk effects. For instance, measurements of spin current generated by SHE are inevitably affected by the spin relaxation at the Pt interfaces, and by its generation via the interfacial Rashba effect [27]. Indeed, the apparent spin Hall angle has been shown to depend on the transparency of the interfaces [23]. Measurements of λ based on the spin absorption efficiency [21...

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“…Introduction.-Spin transport in magnetic insulators and through metal/insulator interfaces is extensively studied in the fields of spintronics and spincaloritronics, providing new routes for information technologies and heat-to-electricity conversion [1][2][3]. A key role in spin caloritronics is played by the longitudinal spin Seebeck effect (LSSE), which describes spin transport through the interface between a normal metal and a magnetic insulator upon heat transport through that interface [4].…”

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confidence: 99%