Current-driven magnetic domain wall motion and its real-time detection

Kim, Kab‐Jin; Yoshimura, Y.; Ono, Teruo

doi:10.7567/jjap.56.0802a4

Cited by 20 publications

(16 citation statements)

References 99 publications

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“…While variety of techniques have been developed to determined the position of a moving DW [6,88,89], they often have limitations in resolution or acquisition speed [89]. Figure 5 shows that temporal profiles of I Sx p (t) and I Sy p (t) are tightly correlated with the DW position, as well as that their amplitude increases (decreases) as the DW approaches (distances from) the NM lead.…”

Section: Dw Motion Driven By Steady Current: Spin and Charge Pumpingmentioning

confidence: 99%

“…The current-driven dynamics of collinear, such as macrospin [1][2][3], and noncollinear, such as domain walls (DWs) [4][5][6][7][8] and skyrmions [9,10], textures of localized magnetic moments are both a fundamental problem for nonequilibrium quantum many-body physics and a key resource for next generation spintronics [11][12][13][14]. For example, the current-driven spin torque induced magnetization dynamics in magnetic tunnel junctions (MTJs) [1,3] or ferromagnet/spin-orbit-coupled-material bilayers [8,15,16] can implement variety of functionalities, such as nonvolatile magnetic random access memories (MRAM), microwave oscillators, microwave detectors, spin-wave emitters, memristors and artificial neural networks [11][12][13][14].…”

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confidence: 99%

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Spin and Charge Pumping by a Steady or Pulse-Current-Driven Magnetic Domain Wall: A Self-Consistent Multiscale Time-Dependent Quantum-Classical Hybrid Approach

et al. 2018

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We introduce a multiscale framework which combines time-dependent nonequilibrium Green function (TD-NEGF) algorithms, scaling linearly in the number of time steps and describing quantummechanically conduction electrons in the presence of time-dependent fields of arbitrary strength or frequency, with classical time evolution of localized magnetic moments described by the Landau-Lifshitz-Gilbert (LLG) equation. The TD-NEGF+LLG framework can be applied to a variety of problems where current-driven spin torque induces dynamics of magnetic moments as the key resource for next generation spintronics. Previous approaches to such nonequilibrium many-body system (like steady-state-NEGF+LLG framework) neglect noncommutativity of a quantum Hamiltonian of conduction electrons at different times and, therefore, the impact of time-dependent magnetic moments on electrons leading to pumping of spin and charge currents. The pumped currents can, in turn, self-consistently affect the dynamics of magnetic moments themselves. Using magnetic domain wall (DW) as an example, we predict that its motion will pump time-dependent spin and charge currents (on the top of unpolarized DC charge current injected through normal metal leads to drive the DW motion), where the latter can be viewed as a realization of quantum charge pumping due to time-dependence of the Hamiltonian and left-right symmetry breaking of the two-terminal device structure. The conversion of AC components of spin current, whose amplitude increases (decreases) as the DW approaches (distances from) the normal metal lead, into AC voltage via the inverse spin Hall effect offers a tool to precisely track the DW position along magnetic nanowire. We also quantify the DW transient inertial displacement due to its acceleration and deceleration by pulse current and the entailed spin and charge pumping. Finally, TD-NEGF+LLG as a nonperturbative (i.e., numerically exact) framework allows us to establish the limits of validity of the so-called spin-motive force (SMF) theory for pumped charge current by time-dependent magnetic textures-the perturbative analytical formula of SMF theory becomes inapplicable for large frequencies (but unrealistic in magnetic system) and, more importantly, for increasing noncollinearity when the angles between neighboring magnetic moments exceed 10 • . arXiv:1802.05682v3 [cond-mat.mes-hall] 9 Aug 2018 x y z Electron Flow J t t J sd

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Section: Dw Motion Driven By Steady Current: Spin and Charge Pumpingmentioning

confidence: 99%

mentioning

confidence: 99%

Spin and Charge Pumping by a Steady or Pulse-Current-Driven Magnetic Domain Wall: A Self-Consistent Multiscale Time-Dependent Quantum-Classical Hybrid Approach

et al. 2018

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“…Domain wall dynamics has been widely observed in magnetic materials, which has given us good understanding of the spin torques that can be present in each system. [83,84] Magnetic skyrmions, namely point-like structures characterized by swirling spin textures inside, also play an important role in the studies on magnetic materials. While skyrmions usually form lattice structure, called skyrmion crystal, at ground state, detection and manipulation of individual skyrmions have been successfully demonstrated in recent experiments.…”

Section: Magnetic Textures In Normal Metals: Spin Gauge Fieldsmentioning

confidence: 99%

Magnetic Textures and Dynamics in Magnetic Weyl Semimetals

Araki

2019

Annalen der Physik

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Recent theoretical and experimental attempts have been successful in finding magnetic Weyl semimetal phases, which show nodal‐point structure in the electronic bands as well as magnetic orders. Beyond uniform ferromagnetic or antiferromagnetic orders, nonuniform magnetic textures, such as domain walls and skyrmions, enrich the properties of the Weyl electrons even more in such materials. Here, a topical review on interplay between Weyl electrons and magnetic textures in those magnetic Weyl semimetals is given. The basics of magnetic textures in nontopological magnetic metals are reviewed first, and then the effect of magnetic textures in Weyl semimetals is discussed, regarding the recent theoretical and experimental progress therein. The idea of the fictitious “axial gauge fields” is pointed out, which effectively describes the effect of magnetic textures on the Weyl electrons and can well account for the properties of the electrons localized around magnetic domain walls.

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“…Since there is no mechanical motion in DW memory's reading and writing processes, it is expected to be more energy efficient. Pulsed spin current with a duration of nanoseconds and an amplitude of 1010 A/m2 [11][12][13][14], was reported to drive DWs, up to high speeds of kilometre per second [15].…”

Section: Introductionmentioning

confidence: 99%