Electric Manipulation of Spin Relaxation Using the Spin Hall Effect

Ando, Kotoji; Takahashi, Saburo; Harii, Kiyonori; Sasage, K.; Ieda, Jun’ichi; Maekawa, Sadamichi; Saitoh, Eiji

doi:10.1103/physrevlett.101.036601

Cited by 622 publications

(569 citation statements)

References 28 publications

Supporting

Mentioning

545

Contrasting

Unclassified

Order By: Relevance

“…Microwave signal emission, shown in Fig. 2, is only observed above a critical current I c with the current polarity corresponding to SO torques acting as negative damping 25 . We measured the microwave emission for five nominally identical devices and found similar results for all these samples.…”

Section: Resultsmentioning

confidence: 99%

“…To study self-oscillatory magnetic dynamics excited by SO torques, we apply a saturating magnetic field (H40.5 kOe) in the plane of the sample in a direction nearly perpendicular to the nanowire axis. In this configuration, SO torques applied to the Py magnetization act as effective magnetic damping 25 . We apply a direct current bias I dc to the nanowire and measure the microwave signal emitted by the device using a spectrum analyzer 3 .…”

Section: Resultsmentioning

confidence: 99%

“…Recently, a new type of STO based on current-induced spin orbit (SO) torques in a Permalloy(Py)/platinum(Pt) bilayer was demonstrated [16][17][18] . Spin orbit torques [19][20][21] in this system can arise from the spin Hall effect in Pt [22][23][24][25][26][27][28] and the Rashba effect at the Pt/Py interface [29][30][31][32] .…”

mentioning

confidence: 99%

See 2 more Smart Citations

Nanowire spin torque oscillator driven by spin orbit torques

et al. 2014

View full text Add to dashboard Cite

Spin torque from spin current applied to a nanoscale region of a ferromagnet can act as negative magnetic damping and thereby excite self-oscillations of its magnetization. In contrast, spin torque uniformly applied to the magnetization of an extended ferromagnetic film does not generate self-oscillatory magnetic dynamics but leads to reduction of the saturation magnetization. Here we report studies of the effect of spin torque on a system of intermediate dimensionality-a ferromagnetic nanowire. We observe coherent self-oscillations of magnetization in a ferromagnetic nanowire serving as the active region of a spin torque oscillator driven by spin orbit torques. Our work demonstrates that magnetization selfoscillations can be excited in a one-dimensional magnetic system and that dimensions of the active region of spin torque oscillators can be extended beyond the nanometre length scale.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Nanowire spin torque oscillator driven by spin orbit torques

et al. 2014

View full text Add to dashboard Cite

show abstract

“…[3][4][5] For the opposite effect, to use Pt as a spin current injector, a charge current is sent through the Pt, creating a transverse spin accumulation by the spin-Hall effect (SHE). [6][7][8] Recently, Weiler et al 9 and Huang et al 10 observed magnetoresistance (MR) effects in Pt on YIG and related those effects to magnetic proximity. These MR effects have been further investigated by Nakayama et al 11 and they found and explained a new magnetoresistance, called spin-Hall magnetoresistance (SMR).…”

Section: Introductionmentioning

confidence: 99%

Spin-Hall magnetoresistance in platinum on yttrium iron garnet: Dependence on platinum thickness and in-plane/out-of-plane magnetization

et al. 2013

View full text Add to dashboard Cite

Spin-Hall magnetoresistance in platinum on yttrium iron garnet Vlietstra, N.; Shan, J.; Castel, V.; van Wees, B. J.; Ben Youssef, J. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. The occurrence of spin-Hall magnetoresistance (SMR) in platinum (Pt) on top of yttrium iron garnet (YIG) has been investigated, for both in-plane and out-of-plane applied magnetic fields and for different Pt thicknesses [3, 4, 8, and 35 nm]. Our experiments show that the SMR signal directly depends on the in-plane and out-of-plane magnetization directions of the YIG. This confirms the theoretical description, where the SMR occurs due to the interplay of the spin-orbit interaction in the Pt and the spin-mixing conductance at the YIG/Pt interface. Additionally, the sensitivity of the SMR and spin pumping signals on the YIG/Pt interface conditions is shown by comparing two different deposition techniques (e-beam evaporation and dc sputtering).

show abstract

“…The contribution of quantum fluctuations to spin transfer in antiferromagnets [43] must be larger than in ferromagnets, due to higher magnon frequencies. Quantum fluctuations may contribute to other phenomena involving interaction between magnetization and conduction electrons, including spin pumping [44], spin-orbit [45][46][47], optically driven [48][49][50], and spin-caloritronic effects [51][52][53][54][55].…”

Section: -3mentioning

confidence: 99%

Quantum Spin Torque

Zhang

2017

Physics

View full text Add to dashboard Cite

We utilize a nanoscale magnetic spin-valve structure to demonstrate that current-induced magnetization fluctuations at cryogenic temperatures result predominantly from the quantum fluctuations enhanced by the spin transfer effect. The demonstrated spin transfer due to quantum magnetization fluctuations is distinguished from the previously established current-induced effects by a nonsmooth piecewise-linear dependence of the fluctuation intensity on current. It can be driven not only by the directional flows of spinpolarized electrons, but also by their thermal motion and by scattering of unpolarized electrons. This effect is expected to remain non-negligible even at room temperature, and entails a ubiquitous inelastic contribution to spin-polarizing properties of magnetic interfaces. DOI: 10.1103/PhysRevLett.119.257201 Spin transfer [1-3]-the transfer of angular momentum from spin-polarized electrical current to magnetic materials-has been extensively researched as an efficient mechanism for the electronic manipulation of nanomagnetic systems, advancing our understanding of nanomagnetism and electronic transport, and enabling the development of magnetoelectronic nanodevices [3][4][5][6][7][8][9][10][11][12][13][14][15]. This effect can be understood based on the argument of angular momentum conservation for spin-polarized electrons, scattered by a ferromagnet whose magnetization ⃗ M is not aligned with their polarization. The component of the electron spin transverse to ⃗ M becomes absorbed, exerting a spin transfer torque (STT) on the magnetization. In nanomagnetic devices such as spin valve nanopillars [ Fig. 1(a)], STT can enhance thermal fluctuations of magnetization [ Fig. 1(b)], resulting in its reversal [5,16] or auto-oscillation [6], which can be utilized in memory, microwave generation, and spin-wave logic [17,18].The approximation for the magnetization as a thermally fluctuating classical vector ⃗ M provides an excellent description for the quasiuniform magnetization dynamics [19]. However, for typical transition-metal ferromagnets, the frequencies f of the dynamical magnetization modes extend to ∼100 THz [19,20]. The modes with f > 6 THz are frozen out at room temperature (f > 70 GHz at T ¼ 3.4 K), and the effect of STT on them cannot be described in terms of the enhancement or suppression of thermal fluctuations. Such high-frequency modes are only now becoming experimentally accessible [21][22][23][24], and their role in spin transfer remains unexplored.Here, we introduce a frequency nonselective, magnetoelectronic approach allowing measurements of the effects of spin transfer on the magnetization fluctuations, not limited to quasiuniform modes. Our central result is that at low temperatures the current-dependent fluctuations arise predominantly from the quantum fluctuations enhanced by spin transfer; the quantum contribution remains non-negligible even at room temperature. The observed effect is analogous to the well-studied spontaneous emission of a photon by a two-level system, also caused by qu...

show abstract

Electric Manipulation of Spin Relaxation Using the Spin Hall Effect

Cited by 622 publications

References 28 publications

Nanowire spin torque oscillator driven by spin orbit torques

Nanowire spin torque oscillator driven by spin orbit torques

Spin-Hall magnetoresistance in platinum on yttrium iron garnet: Dependence on platinum thickness and in-plane/out-of-plane magnetization

Quantum Spin Torque

Contact Info

Product

Resources

About