Field-free deterministic ultrafast creation of magnetic skyrmions by spin–orbit torques

Büttner, Felix; Lemesh, Ivan; Schneider, Michael; Pfau, Bastian; Günther, C.; Hessing, Piet; Geilhufe, Jan; Caretta, Lucas; Engel, Dieter; Krüger, Benjamin; Viefhaus, Jens; Eisebitt, Stefan; Beach, Geoffrey S. D.

doi:10.1038/nnano.2017.178

Cited by 243 publications

(267 citation statements)

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“…The stabilization mechanism of the zero-field SKBs may be attributed to the pinning effect of the geometric edges and the topological protection. 23 To gain a comprehensive understanding of the effect of the width confinement on the formation of SKBs, we investigated the domain evolution in nanostripes with various widths, Figure 3c) suggests that the SKBs intend to form a hexagonal lattice if they are densely packed. 42 By further decreasing the width, a straight, single chain of SKBs gradually formed.…”

Section: Resultsmentioning

confidence: 99%

“…7-12 This fascinating topological property, combined with their nanoscale size and stable particle-like features make skyrmions promising candidate for carrying magnetic information in further high-density and low-power consumption spintronic devices based on the racetrack memory concept. 8,13,[14][15][16][17][18][19][20][21][22][23][24] Recent studies showed that some non-chiral centrosymmetric magnets could host skyrmion bubbles (SKBs), 25-32 stabilized by the interplay of the external magnetic field, ferromagnetic exchange interaction, uniaxial magnetic anisotropy, and dipole-dipole interaction (DDI). SKBs are topologically equivalent to magnetic skyrmions and exhibit similar topological properties, such as the topological Hall effect, 27 skyrmion Hall effect, 33 and ultra-low driving current density for current-induced motion.…”

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confidence: 99%

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Manipulating the Topology of Nanoscale Skyrmion Bubbles by Spatially Geometric Confinement

Hou

Zhang

et al. 2019

ACS Nano

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The discovery of magnetic skyrmion bubbles in centrosymmetric magnets has been receiving increasing interest from the research community, due to the fascinating physics of topological spin textures and its possible applications to spintronics. However, key challenges remain, such as how to manipulate the nucleation of skyrmion bubbles to exclude the trivial bubbles or metastable skyrmion bubbles that usually coexist with skyrmion bubbles in the centrosymmetric magnets. Here, we report having successfully performed this task by applying spatially geometric confinement to a centrosymmetric frustrated Fe 3 Sn 2 magnet. We demonstrate that the spatially geometric confinement can indeed stabilize the skyrmion bubbles, by effectively suppressing the formation of trivial bubbles and metastable skyrmion bubbles. We also show that the critical magnetic field for the nucleation of the skyrmion bubbles in the confined Fe 3 Sn 2 nanostripes is drastically less, by an order of magnitude, than that what is required in the thin plate without geometrical confinement. By analyzing how the width and thickness of the nanostripes affect the spin textures of skyrmion bubbles, we infer that the topological transition of skyrmion bubbles is closely related to the dipole-dipole interaction, which we find is consistent with theoretical simulations. The results presented here represent an important step forward in manipulating the topological spin textures of skyrmion bubbles, making us closer to achieving the fabrication of skyrmion-based racetrack memory devices.Magnetic skyrmions are topologically protected vortex-like objects that were first discovered in the chiral, non-centrosymmetric magnets 1-6 where they are stabilized by the Dzyaloshinskii-Moriya interaction (DMI). Unlike the conventional, "rigid" magnetic domain walls, they are flexible in shape-deformation to avoid pinning centres, 7,8 and therefore only an ultra-low current density is needed to drive them to move. 7-12 This fascinating topological property, combined with their nanoscale size and stable particle-like features make skyrmions promising candidate for carrying magnetic information in further high-density and low-power consumption spintronic devices based on the racetrack memory concept. 8,13,[14][15][16][17][18][19][20][21][22][23][24] Recent studies showed that some non-chiral centrosymmetric magnets could host skyrmion bubbles (SKBs), 25-32 stabilized by the interplay of the external magnetic field, ferromagnetic exchange interaction, uniaxial magnetic anisotropy, and dipole-dipole interaction (DDI). SKBs are topologically equivalent to magnetic skyrmions and exhibit similar topological properties, such as the topological Hall effect, 27 skyrmion Hall effect, 33 and ultra-low driving current density for current-induced motion. 25 More importantly, SKBs show a significantly high thermal stability over a wide temperature range crossing room temperature, 27,28,34 showing a high potential of SKBs for the construction of memory devices.Contrary to DMI-stabilized skyr...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Manipulating the Topology of Nanoscale Skyrmion Bubbles by Spatially Geometric Confinement

Hou

Zhang

et al. 2019

ACS Nano

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“…Fig. 10a shows an example of skyrmion nucleation by the Spin Transfer Torque induced near a constriction by current pulses [109], [110]. Nucleation can also be achieved by replacing constrictions by prepared defects or local injectors from outside the film [103].…”

Section: Hdmi = (S1  S2)d12 (Eq2)mentioning

confidence: 99%

“…(a) Creation of skyrmions at the edge of a constriction in a (Pt/CoFeB/MgO) x 15 multilayer by successive current pulses in opposite directions[110]. (b) Detection of the presence of a single skyrmion by the change in AHE[111].…”

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confidence: 99%

Spintronics, from giant magnetoresistance to magnetic skyrmions and topological insulators

Fert

Dau

2019

Comptes Rendus. Physique

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This article aims at giving a general presentation of spintronics, an important field of research developing today along many new directions in physics of condensed matter. We tried to present simply the physical phenomena involved in spintronicsno equations but many schematics. We also described the applications of spintronics, those of today and those expected to have an important impact on the next developments of the information and communication technologies. This article was published in the Comptes Rendus Physique of the French Academy of Sciences (https://doi.

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“…A multitude of nucleation methods have been proposed in recent years and these can be put into three categories based on: electrical currents, [ 10,19–24 ] laser pulses, [ 25–27 ] and locally applied electric fields. [ 28,29 ] Skyrmions can also nucleate at naturally occurring defects in the material; [ 30,31 ] theoretical studies, which consider nonmagnetic defects, find that defects both localize skyrmion nucleation and reduce the nucleation energy barrier. [ 32,33 ] However, because of their random location and variable character, naturally occurring defects offer little control over the formation of skyrmions and are unsuitable as a nucleation method for devices.…”

Section: Introductionmentioning

confidence: 99%

Controlled Individual Skyrmion Nucleation at Artificial Defects Formed by Ion Irradiation

Fallon

Hughes

Zeissler

et al. 2020

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Magnetic skyrmions are particle‐like deformations in a magnetic texture. They have great potential as information carriers in spintronic devices because of their interesting topological properties and favorable motion under spin currents. A new method of nucleating skyrmions at nanoscale defect sites, created in a controlled manner with focused ion beam irradiation, in polycrystalline magnetic multilayer samples with an interfacial Dzyaloshinskii–Moriya interaction, is reported. This new method has three notable advantages: 1) localization of nucleation; 2) stability over a larger range of external field strengths, including stability at zero field; and 3) existence of skyrmions in material systems where, prior to defect fabrication, skyrmions were not previously obtained by field cycling. Additionally, it is observed that the size of defect nucleated skyrmions is uninfluenced by the defect itself—provided that the artificial defects are controlled to be smaller than the inherent skyrmion size. All of these characteristics are expected to be useful toward the goal of realizing a skyrmion‐based spintronic device. This phenomenon is studied with a range of transmission electron microscopy techniques to probe quantitatively the magnetic behavior at the defects with applied field and correlate this with the structural impact of the defects.

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Field-free deterministic ultrafast creation of magnetic skyrmions by spin–orbit torques

Cited by 243 publications

References 35 publications

Manipulating the Topology of Nanoscale Skyrmion Bubbles by Spatially Geometric Confinement

Manipulating the Topology of Nanoscale Skyrmion Bubbles by Spatially Geometric Confinement

Spintronics, from giant magnetoresistance to magnetic skyrmions and topological insulators

Controlled Individual Skyrmion Nucleation at Artificial Defects Formed by Ion Irradiation

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