Relationship between Nonadiabaticity and Damping in Permalloy Studied by Current Induced Spin Structure Transformations

Heyne, Lutz; Kläui, Mathias; Backes, Dirk; Moore, T. A.; Krzyk, Stephen; Rüdiger, Ulrich; Heyderman, Laura J.; Rodríguez, A. Fraile; Nolting, F.; Menteş, Tevfik Onur; Niño, M. Á.; Locatelli, Andrea; Kirsch, K.; Mattheis, R.

doi:10.1103/physrevlett.100.066603

Cited by 86 publications

(65 citation statements)

References 27 publications

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“…We group the DWs by their topology, as determined from the PEEM imaging. The threshold current densities for transverse walls are larger compared to those for vortex walls in agreement with previous reported work [17]. For vortex domain walls the threshold current density decreases as the arm width is increased for both Py 99 Gd 1 and Py 90 Gd 10 .…”

supporting

confidence: 80%

“…For transverse domain walls the threshold current is set by the hard axis in-plane anisotropy with the edge roughness contributing a further increase of the threshold current due to extra pinning [17]. is the Gilbert damping and is the non-adiabaticity parameter, as the vortex domain wall is displaced the vortex core attains a transverse displacement dependent on its polarity.…”

mentioning

confidence: 99%

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The increase of the spin-transfer torque threshold current density in coupled vortex domain walls

Lepadatu¹,

Mihai²,

Claydon³

et al. 2011

J. Phys.: Condens. Matter

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Article:Lepadatu, S, Mihai, AP, Claydon, JS et al. (5 more We have studied the dependence on domain wall structure of the spin-transfer torque current density threshold for the onset of wall motion in curved, Gd-doped Ni 80 Fe 20 nanowires with no artificial pinning potentials. For single vortex domain walls, both for 10% and 1% Gd doping concentrations, the threshold current density is inversely proportional to the wire width and significantly lower compared to the threshold current density measured for transverse domain walls. On the other hand for high Gd concentrations and large wire widths, double vortex domain walls are formed which require an increase in the threshold current density compared to single vortex domain walls at the same wire width. We suggest that this is due to the coupling of the vortex cores, which are of opposite chirality, and hence will be acted on by opposing forces arising through the spin-transfer torque effect.

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supporting

confidence: 80%

mentioning

confidence: 99%

The increase of the spin-transfer torque threshold current density in coupled vortex domain walls

Lepadatu¹,

Mihai²,

Claydon³

et al. 2011

J. Phys.: Condens. Matter

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“…The depinning mechanism can reveal details of the interaction between the spin-polarized current and the magnetization, as it was predicted to be often accompanied by a spin structure transformation [3]. Furthermore, other key parameters such as the critical current density [4,5,6,7], the DW velocity [8,9,10], and transformation of the DW's structure [9,10] contain information on the relation between the non-adiabaticity and the damping [11].…”

Section: Introductionmentioning

confidence: 99%

Current-induced domain wall motion in Ni₈₀Fe₂₀ nanowires with low depinning fields

Malinowski¹,

Lörincz²,

Krzyk³

et al. 2010

J. Phys. D: Appl. Phys.

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Abstract.In this paper, we report on domain wall motion induced by current pulses at variable temperature in 900 nm wide and 25 nm thick Ni 80 Fe 20 wires with low pinning fields. By using Ar ion milling to pattern our wires rather than the conventional lift-off technique, a depinning field as low as ∼ 2 − 3 Oe at room temperature is obtained.Comparison with previous results acquired on similar wires with much higher pinning shows that the critical current density scales with the depinning field, leading to a critical current density of ∼ 2.5 × 10 11 A/m 2 at 250 K. Moreover, when a current pulse with a current density larger than the critical current density is injected, the domain wall is not necessarily depinned but it can undergo a modification of its spin structure which hinders current-induced domain wall motion. Hence, reliable propagation of the domain wall requires an accurate adjustment of the pulsed current density.Current induced domain wall motion in Ni 80 Fe 20 nanowires with low depinning fields 2

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“…It is worth comparing our result to available experimental ones. Thomas et al [94], Heyne et al [109], and Eltschka et al [111] have found that vortex cores exhibit a much larger nonadiabaticity (…”

Section: Discussionmentioning

confidence: 99%

“…The importance of the nonadiabaticity for current-induced domain wall motion, has led to a number of theoretical [23][24][25][98][99][100][101][102][103][104][105][106] and experimental studies [94,[107][108][109][110][111][112] to determine the nonadiabatic spin torque parameter. Several mechanisms for the nonadiabatic spin transfer torque have been proposed.…”

Section: Non-local Spin Transfer Torque For a Narrow Domain Wallmentioning

confidence: 99%

Self-consistent calculation of spin transport and magnetization dynamics

et al. 2013

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A spin-polarized current transfers its spin-angular momentum to a local magnetization, exciting various types of current-induced magnetization dynamics. So far, most studies in this field have focused on the direct effect of spin transport on magnetization dynamics, but ignored the feedback from the magnetization dynamics to the spin transport and back to the magnetization dynamics. Although the feedback is usually weak, there are situations when it can play an important role in the dynamics. In such situations, simultaneous, self-consistent calculations of the magnetization dynamics and the spin transport can accurately describe the feedback. This review describes in detail the feedback mechanisms, and presents recent progress in self-consistent calculations of the coupled dynamics. We pay special attention to three representative examples, where the feedback generates non-local effective interactions for the magnetization after the spin accumulation has been integrated out. Possibly the most dramatic feedback example is the dynamic instability in magnetic nanopillars with a single magnetic layer. This instability does not occur without non-local feedback. We demonstrate that full self-consistent calculations generate simulation results in much better agreement with experiments than previous calculations that addressed the feedback effect approximately.The next example is for more typical spin valve nanopillars. Although the effect of feedback is less dramatic because even without feedback the current can make stationary states unstable and induce magnetization oscillation, the feedback can still have important consequences. For instance, we show that the feedback can reduce the linewidth of oscillations, in agreement with experimental observations. A key aspect of this reduction is the suppression of the excitation of short wave length spin waves by the non-local feedback.Finally, we consider nonadiabatic electron transport in narrow domain walls. The non-local feedback in these systems leads to a significant renormalization of the effective nonadiabatic 3 spin transfer torque. These examples show that the self-consistent treatment of spin transport and magnetization dynamics is important for understanding the physics of the coupled dynamics and for providing a bridge between the ongoing research fields of current-induced magnetization dynamics and the newly emerging fields of magnetization-dynamics-induced generation of charge and spin currents.

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Relationship between Nonadiabaticity and Damping in Permalloy Studied by Current Induced Spin Structure Transformations

Cited by 86 publications

References 27 publications

The increase of the spin-transfer torque threshold current density in coupled vortex domain walls

The increase of the spin-transfer torque threshold current density in coupled vortex domain walls

Current-induced domain wall motion in Ni₈₀Fe₂₀ nanowires with low depinning fields

Self-consistent calculation of spin transport and magnetization dynamics

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Relationship between Nonadiabaticity and Damping in Permalloy Studied by Current Induced Spin Structure Transformations

Cited by 86 publications

References 27 publications

The increase of the spin-transfer torque threshold current density in coupled vortex domain walls

The increase of the spin-transfer torque threshold current density in coupled vortex domain walls

Current-induced domain wall motion in Ni80Fe20 nanowires with low depinning fields

Self-consistent calculation of spin transport and magnetization dynamics

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Current-induced domain wall motion in Ni₈₀Fe₂₀ nanowires with low depinning fields