A skyrmion-based spin-torque nano-oscillator with enhanced edge

Feng, Youhua; Xia, Jingbo; Qiu, Lei; Cai, Xinran; Shen, Laichuan; Morvan, F. J.; Zhang, Xichao; Zhou, Yan; Zhao, Guoping

doi:10.1016/j.jmmm.2019.165610

Cited by 43 publications

(26 citation statements)

References 55 publications

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“…The influence of the wavy tails on the dynamics of pseudoskyrmions is an open question. Finally, we expect our skyrmions to be useful for dynamical applications in dots, such as, e.g., skyrmion-based spin-torque nano-oscillators. , …”

Section: Discussionmentioning

confidence: 99%

Intrinsic Mixed Bloch–Néel Character and Chirality of Skyrmions in Asymmetric Epitaxial Trilayers

Olleros-Rodríguez

Guerrero

Camarero

et al. 2020

ACS Appl. Mater. Interfaces

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Recent advances on the stabilization and manipulation of chiral magnetization configurations in systems consisting in alternating atomic layers of ferromagnetic and nonmagnetic materials hold promise of innovation in spintronics technology. The low dimensionality of the systems promotes spin orbit driven interfacial effects like antisymmetric Dzyaloshinskii-Moriya interactions (DMI) and surface magnetic anisotropy, whose relative strengths may be tuned to achieve stable nanometer sized magnetic objects with fixed chirality. While in most of the cases this is obtained by engineering complex multilayers stacks in which interlayer dipolar fields become important, we consider here a simple epitaxial trilayer in which a ferromagnet, with variable thickness, is embedded between a heavy metal and graphene. The latter enhances the perpendicular magnetic anisotropy of the system, promotes a Rashba-type DMI, and can sustain very long spin diffusion length. We use a layer-resolved micromagnetic model (LRM) to describe the magnetization textures and their chirality. Our results demonstrate that for Co thickness larger than 3.6 nm, a skyrmion having an intrinsic mixed Bloch-Néel character with counter-clock-wise chirality is stabilized in the entire (single) Co layer. Noteworthy, for thicknesses larger than 5.4 nm, the skyrmion switches its chirality, from counter-clock-wise to clock-wise.

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Section: Discussionmentioning

confidence: 99%

Intrinsic Mixed Bloch–Néel Character and Chirality of Skyrmions in Asymmetric Epitaxial Trilayers

Olleros-Rodríguez

Guerrero

Camarero

et al. 2020

ACS Appl. Mater. Interfaces

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“…To further understand the tunable dynamic behaviour of the vortex oscillation under the influence of J and K V , we refer to the centre-of-mass dynamics of the magnetic vortex oscillator, which has been well-modelled by the single collective variable Thiele equation [60][61][62].…”

Section: Single Oscillatormentioning

confidence: 99%

“…The rigid profile of the vortex core is described by its position X = X (x(t), y(t)) in the plane, and its velocity is given by dX dt . The gyrotropic force is radial outward which primarily acts to expel the core to the outer shell of the vortex [62]. The second term represents the repulsive (or restoring) force which originates from the edge effect: when the core moves close to the boundary of the vortex structure, the magnetic charges distributed at the cylindrical side wall will generate a centripetal confine potential U (X) to regulate the core inside the vortex region [63].…”

Section: Single Oscillatormentioning

confidence: 99%

Magnetic anisotropy-controlled vortex nano-oscillator for neuromorphic computing

Cui

Liang

et al. 2022

Front. Phys.

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Chiral magnetic vortex has shown great potential for high-density magnetic storage, modern telecommunication and computation devices, thanks to its topological stability and rich dynamic behaviours. Particularly, the synchronization of magnetic vortex nano-oscillators leads to the emergence of fascinating collective phenomena used for microwave generator and neuromorphic computing. In this work, by means of micromagnetic simulations, we create stable chiral magnetic vortices by exploiting the chiral coupling principle and study the gyrotropic motion of the vortex core under spin-transfer torques. The gyrotropic oscillation frequency can be tuned by injecting spin-polarised current as well as the change of the magnetic anisotropy in the vortex area, resulting from the modification of the vortex confine potential and the size of the vortex core. Two vortex nano-oscillators can be synchronized wherein the synchronization state can be modulated by the spin-polarised current and the magnetic anisotropy. Moreover, we demonstrate that the magnetic anisotropy can modify the synchronization patterns when integrating six vortices into an oscillator network, making it potentially serve as an oscillator-based neural network. Our work provides a new route to constructing a flexible oscillator network for neuromorphic computing hardware.

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“…Previous experimental studies have shown that magnetic skyrmions can be observed in systems with bulk or interfacial DMI [14][15][16][17]. The magnetic skyrmions can be used to generate periodic magnetic oscillation signals which show promise in spin-torque oscillators (STOs) [18][19][20][21][22][23][24]. The STOs hold potential applications for nextgeneration microwave signal generators [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43], in which the oscillating elements could use different topologically nontrivial spin textures.…”

Section: Introductionmentioning

confidence: 99%

Spin-Torque Oscillator Based on Magnetic Domain and Meron

Zhang

Cao

et al. 2022

Front. Phys.

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In this work, micromagnetic simulations demonstrate that a steady oscillation mode accompanied by magnetic domain splitting and the creation and annihilation of meron can be excited by spin-polarized currents. It is found that the in-plane magnetic anisotropy and Dzyaloshinskii-Moriya interaction (DMI) have a greater influence on the oscillation frequency. The oscillation frequency can vary from 3 GHz to 31 GHz by controlling anisotropy strength under a fixed current density. By changing DMI strength, the oscillation frequency varies from 9 to 13.6 GHz and from 29.7 to 37 GHz. Compared with ferromagnetic skyrmion-based spin-torque oscillators (STOs), the STOs based on this magnetic domain and meron further increase the oscillation frequency. Our results may provide theoretical support for the research and development of future high-frequency STOs.

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A skyrmion-based spin-torque nano-oscillator with enhanced edge

Cited by 43 publications

References 55 publications

Intrinsic Mixed Bloch–Néel Character and Chirality of Skyrmions in Asymmetric Epitaxial Trilayers

Intrinsic Mixed Bloch–Néel Character and Chirality of Skyrmions in Asymmetric Epitaxial Trilayers

Magnetic anisotropy-controlled vortex nano-oscillator for neuromorphic computing

Spin-Torque Oscillator Based on Magnetic Domain and Meron

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