Spin-transfer-induced precessional magnetization reversal

Kent, Andrew D.; Özyilmaz, Barbaros; Barco, Enrique del

doi:10.1063/1.1739271

Cited by 258 publications

(202 citation statements)

References 12 publications

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“…Owing to their small size (∼ 10 nm) and large velocities (∼ 100 m/s) 9,10 , controllable domain wall motion represents holds real potential for tailoring functional devices with fast writing speeds. In addition, there has been several proposals [11][12][13][14] related to magnetic memory functionality due to the non-volatile nature of magnetic domains. Walker breakdown 15 is nevertheless a The spin-orbit interaction may be either intrinsic or induced via a heavy metal proximate host.…”

Section: Introductionmentioning

confidence: 99%

Asymmetric ferromagnetic resonance, universal Walker breakdown, and counterflow domain wall motion in the presence of multiple spin-orbit torques

Linder

Alidoust

2013

Phys. Rev. B

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We study the motion of several types of domain wall profiles in spin-orbit coupled magnetic nanowires and also the influence of spin-orbit interaction on the ferromagnetic resonance of uniform magnetic films. Whereas domain wall motion in systems without correlations between spin-space and real-space is not sensitive to the precise magnetization texture of the domain wall, spin-orbit interactions break the equivalence between such textures due to the coupling between the momentum and spin of the electrons. In particular, we extend previous studies by fully considering not only the field-like contribution from the spin-orbit torque, but also the recently derived Slonczewski-like spin-orbit torque. We show that the latter interaction affects both the domain wall velocity and the Walker breakdown threshold non-trivially, which suggests that it should be accounted in experimental data analysis. We find that the presence of multiple spin-orbit torques may render the Walker breakdown to be universal in the sense that the threshold is completely independent on the material-dependent Gilbert damping α, non-adiabaticity β, and the chirality σ of the domain wall. We also find that domain wall motion against the current injection is sustained in the presence of multiple spin-orbit torques and that the wall profile will determine the qualitative influence of these different types of torques (e.g. field-like and Slonczewski-like). In addition, we consider a uniform ferromagnetic layer under a current bias, and find that the resonance frequency becomes asymmetric against the current direction in the presence of Slonczewski-like spin-orbit coupling. This is in contrast with those cases where such an interaction is absent, where the frequency is found to be symmetric with respect to the current direction. This finding shows that spin-orbit interactions may offer additional control over pumped and absorbed energy in a ferromagnetic resonance setup by manipulating the injected current direction.

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Section: Introductionmentioning

confidence: 99%

Asymmetric ferromagnetic resonance, universal Walker breakdown, and counterflow domain wall motion in the presence of multiple spin-orbit torques

Linder

Alidoust

2013

Phys. Rev. B

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“…This will allow efficient use of spin current for magnetic reversal with a reduced switching threshold [9] and a faster switching process [10]. Recent work by Mangin et al.…”

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confidence: 99%

“…This will allow efficient use of spin current for magnetic reversal with a reduced switching threshold [9] and a faster switching process [10]. Recent work by Mangin et al [11] has demonstrated improvements of spin-torque efficiency in a spin valve that has perpendicularly magnetized Co/Ni synthetic layers.…”

mentioning

confidence: 99%

Spin-torque driven ferromagnetic resonance of Co∕Ni synthetic layers in spin valves

Chen

Beaujour

Loubens

et al. 2008

Applied Physics Letters

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Spin-torque driven ferromagnetic resonance (ST-FMR) is used to study thin Co/Ni synthetic layers with perpendicular anisotropy confined in spin-valve based nanojunctions. Field swept ST-FMR measurements were conducted with a magnetic field applied perpendicular to the layer surface. The resonance lines were measured under low amplitude rf excitation, from 1 to 20 GHz. These results are compared with those obtained using conventional rf field driven FMR on extended films with the same Co/Ni layer structure. The layers confined in spin valves have a lower resonance field, a narrower resonance linewidth and approximately the same linewidth vs frequency slope, implying the same damping parameter. The critical current for magnetic excitations is determined from measurements of the resonance linewidth vs dc current and is in accord with the one determined from I-V measurements.Spin-transfer torque has been theoretically predicted and experimentally demonstrated to drive magnetic excitations in nanostructured spin valves and magnetic tunnel junctions [1,2,3,4,5]. With an rf current, spin transfer can be used to study ferromagnetic resonance [6,7]. This technique, known as spin-torque driven ferromagnetic resonance (ST-FMR), enables quantitative studies of the magnetic properties of thin layers in a spin-transfer device. Specifically, the layer magnetic anisotropy and damping can be determined [8], which are important parameters that need to be optimized in spin-torque-based memory and rf oscillator applications.Spin-transfer memory devices will likely include magnetic layers with perpendicular magnetic anisotropy that counteracts their shape-induced easy-plane anisotropy. This will allow efficient use of spin current for magnetic reversal with a reduced switching threshold [9] and a faster switching process [10]. Recent work by Mangin et al. [11] has demonstrated improvements of spin-torque efficiency in a spin valve that has perpendicularly magnetized Co/Ni synthetic layers. For further optimization of perpendicular anisotropy materials, it is important to have quantitative measurements of their anisotropy field and damping in a nanostructured device, as both of these parameters directly affect the threshold current for spintransfer induced switching.In this Letter, we present ST-FMR studies of bilayer nanopillars, where the thin (free) layer is composed of a Co/Ni synthetic layer and the thick (fixed) layer is pure Co. The magnetic anisotropy and damping of the Co/Ni have been determined by ST-FMR. We compare these results with those obtained from extended films with the same Co/Ni layer stack measured using traditional rf field driven FMR.Pillar junctions with submicron lateral dimensions ( Fig. 1(a)) were patterned on a silicon wafer using a nanostencil process [12]. Junctions were deposited using metal evaporation with the layer structure 1.5 nm (a)

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“…Moreover, the reliable ultrafast precessional reveral has been achieved by a picosecond spin-polarized current pulse in the spin valves and magnetic tunnel junctions. [15][16][17][18][19][20][21] It has been demonstrated theoretically and experimentally that the accurate control of the pulse duration is necessary to realize a reliable precessional reversal either by magnetic field or by spinpolarized current. There is a time window for the pulse duration.…”

Section: Introductionmentioning

confidence: 99%

Effects of spin-polarized current on pulse field-induced precessional magnetization reversal

et al. 2012

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We investigate effects of a small DC spin-polarized current on the pulse field-induced precessional magnetization reversal in a thin elliptic magnetic element by micromagnetic simulations. We find that the spin-polarized current not only broadens the time window of the pulse duration, in which a successful precessional reversal is achievable, but also significantly suppresses the magnetization ringing after the reversal. The pulse time window as well as the decay rate of the ringing increase with increasing the current density. When a spin-polarized current with 5 MA/cm2 is applied, the time window increases from 80 ps to 112 ps, and the relaxation time of the ringing decreases from 1.1 ns to 0.32 ns. Our results provide useful information to achieve magnetic nanodevices based on precessional switching

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Spin-transfer-induced precessional magnetization reversal

Cited by 258 publications

References 12 publications

Asymmetric ferromagnetic resonance, universal Walker breakdown, and counterflow domain wall motion in the presence of multiple spin-orbit torques

Asymmetric ferromagnetic resonance, universal Walker breakdown, and counterflow domain wall motion in the presence of multiple spin-orbit torques

Spin-torque driven ferromagnetic resonance of Co∕Ni synthetic layers in spin valves

Effects of spin-polarized current on pulse field-induced precessional magnetization reversal

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