Variational calculus for vertical bloch lines.

Nakatani, Yoshinobu; Hayashi, N.

doi:10.3379/jmsjmag.11.133

Cited by 17 publications

(20 citation statements)

References 3 publications

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“…provides dynamical descriptions of TDWs, where X represents related collective coordinates. Early simulations confirmed that in FM nanostrips with small enough cross section, transverse DWs (TDWs) have the lowest energy among all meta-stable states [33,34]. In 2012, further simulations revealed that the stability range of TDW in free layers of LNSVs can be shifted towards larger cross section compared with monolayer strips, due to a magnetostatic screening effect between the free and pinned layers [35].…”

Section: Model and Methodsmentioning

confidence: 98%

Ultrahigh differential mobility and velocity of Néel domain walls in spin valves with planar-transverse polarizers and perpendicularly injected small currents

Lü

2019

Phys. Rev. B

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Transverse domain wall (TDW) dynamics in long and narrow spin valves with perpendicular current injection is theoretically investigated. We demonstrate that stable traveling-wave motion of TDWs with finite velocity survives for strong enough planar-transverse polarizers. For typical ferromagnetic materials (for example, Co) and achievable spin polarization (P = 0.6), TDWs acquire a velocity of 10 3 m/s under a current density below 10 7 A/cm 2 . This efficiency is comparable with that of perpendicular polarizers. More importantly, in this case the wall has ultra-high "differential mobility" around the onset of stable wall excitation. Our results open new possibilities for developing magnetic nanodevices based on TDW propagation with low energy consumption. Also, analytics for parallel and perpendicular polarizers perfectly explains existing simulation findings. Finally, further boosting of TDWs by external uniform transverse magnetic fields is investigated and turns out to be efficient.

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Section: Model and Methodsmentioning

confidence: 98%

Ultrahigh differential mobility and velocity of Néel domain walls in spin valves with planar-transverse polarizers and perpendicularly injected small currents

Lü

2019

Phys. Rev. B

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“…The unit cell has a dimension of 4×4×t nm 3 . In order to investigate the effect of the aspect ratio on the dynamics of the TW, we fixed the cross-section area (w(width)×t(thickness)) of the nanostrip as 720 nm 2 where TW is a stable according to the phase diagram of the DW [13,14]. It has been reported that the J C of a rigid TW is linearly proportional to the shape anisotropy in the adiabatic limit [11].…”

Section: Micromagnetic Simulationmentioning

confidence: 99%

Effect of aspect ratio of nanostrip on transformation of transverse domain wall due to adiabatic spin torque

Seo¹,

Kim²,

Lee³

et al. 2007

Physica Status Solidi (b)

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We have studied the current-induced dynamics of the transverse domain wall in the adiabatic limit. Above the threshold current density for the continuous domain wall motion, the transverse wall is transformed by the injection of the antivortex. In general, the wall velocity increases and the wall width decreases as the antivortex is injected. However, detailed time-dependent profiles of the wall velocity and the wall width are significantly affected by the aspect ratio of the nanostrip. The mean velocity of the TW decreases as the aspect ratio increases.

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“…In the last decade, domain wall (DW) dynamics in ferromagnetic nanostructures have received considerable attention, especially due to technological applications in spintronics, including memory 1,2 and logic devices [3][4][5] . Typically, DW dynamics in nanostrips and wires is induced by external magnetic fields [6][7][8][9][10][11][12][13][14][15][16] or spin-polarized electric currents [17][18][19][20][21][22] . Details of the resulting DW dynamics depend on the DW structure, which in turn depends on the material and geometry being considered.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, for soft magnetic materials such as permalloy, the negligible magnetocrystalline anisotropy implies that the physics of the system is dictated by the competition between exchange interactions and shape anisotropy due to magnetostatic effects. The resulting in-plane domains along the long axis of the strip are separated by DWs with equilibrium structures ranging from relatively simple transverse and vortex DWs to more complex multi-vortex walls when increasing the strip width from tens and hundreds of nanometers towards several micrometers 8,9,[25][26][27] .…”

Section: Introductionmentioning

confidence: 99%

“…Most of the previous works related to in-plane materials have focused on the study of DW dynamics in narrow permalloy strips where the equilibrium DW structure is the transverse or vortex wall [7][8][9][10][11][12][28][29][30][31] . The DW dynamics for these systems is characterized by the emergence of an instability, often referred to as the Walker breakdown 32 , which appears when the DW internal degrees of freedom are excited by a strong enough external driving force.…”

Section: Introductionmentioning

confidence: 99%

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Fast vortex wall motion in wide permalloy strips from double switching of the vortex core

Estévez

Laurson

2017

Phys. Rev. B

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We study vortex domain wall dynamics in wide permalloy strips driven by applied magnetic fields and spin-polarized electric currents. As recently reported [V. Estévez and L. Laurson, Phys. Rev. B, 93, 064403 (2016)], for sufficiently wide strips and above a threshold field, periodic dynamics of the vortex core are localized in the vicinity of one of the strip edges, and the velocity drop typically observed for narrow strips is replaced by a high-velocity plateau. Here, we analyze this behavior in more detail by means of micromagnetic simulations. We show that the high-velocity plateau originates from a repeated double switching of the magnetic vortex core, underlying the periodic vortex core dynamics in the vicinity of the strip edge, i.e., the "attraction-repulsion" effect. We also discuss the corresponding dynamics driven by spin-polarized currents, as well as the effect of including quenched random structural disorder to the system.

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Variational calculus for vertical bloch lines.

Cited by 17 publications

References 3 publications

Ultrahigh differential mobility and velocity of Néel domain walls in spin valves with planar-transverse polarizers and perpendicularly injected small currents

Ultrahigh differential mobility and velocity of Néel domain walls in spin valves with planar-transverse polarizers and perpendicularly injected small currents

Effect of aspect ratio of nanostrip on transformation of transverse domain wall due to adiabatic spin torque

Fast vortex wall motion in wide permalloy strips from double switching of the vortex core

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