A Skyrmion Diode Based on Skyrmion Hall Effect

Feng, Youhua; Zhang, Xi; Zhao, Guoping; Xiang, Gang

doi:10.1109/ted.2021.3138837

“…In diodes, the threshold for transport is different for one direction of drive compared to the other, and the diode effect can be used to create a variety of logic devices [55,56]. A number of skyrmion diode devices have been proposed using voltage controlled potential barriers [57], asymmetric substrates [58], and even the asymmetry of the motion from the Hall effect [59]. In our system, the diode effect arises because the skyrmions are more susceptible to clogging for hard direction driving than for easy direction driving.…”

Section: Skyrmion Diode Effectmentioning

confidence: 99%

Clogging, diode and collective effects of skyrmions in funnel geometries

Souza

¹

,

Vizarim

²

,

Reichhardt

³

et al. 2022

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Using a particle-based model, we examine the collective dynamics of skyrmions interacting with a funnel potential under dc driving as the skyrmion density and relative strength of the Magnus and damping terms are varied. For driving in the easy direction, we find that increasing the skyrmion density reduces the average skyrmion velocity due to jamming of skyrmions near the funnel opening, while the Magnus force causes skyrmions to accumulate on one side of the funnel array. For driving in the hard direction, there is a critical skyrmion density below which the skyrmions become trapped. Above this critical value, a clogging effect appears with multiple depinning and repinning states where the skyrmions can rearrange into different clogged configurations, while at higher drives, the velocity-force curves become continuous. When skyrmions pile up near the funnel opening, the effective size of the opening is reduced and the passage of other skyrmions is blocked by the repulsive skyrmion-skyrmion interactions. We observe a strong diode effect in which the critical depinning force is higher and the velocity response is smaller for hard direction driving. As the ratio of Magnus force to dissipative term is varied, the skyrmion velocity varies in a non-linear and non-monotonic way due to the pile up of skyrmions on one side of the funnels. At high Magnus forces, the clogging effect for hard direction driving is diminished.

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“…In diodes, the threshold for transport is different for one direction of drive compared to the other, and the diode effect can be used to create a variety of logic devices [51,52]. A number of skyrmion diode devices have been proposed using voltage controlled potential barriers [53], asymmetric substrates [54], and even the asymmetry of the motion from the Hall effect [55]. In our system, the diode effect arises because the skyrmions are more susceptible to clogging for hard direction driving than for easy direction driving.…”

Section: Skyrmion Diode Effectmentioning

confidence: 99%

Clogging, Diode and Collective Effects of Skyrmions in Funnel Geometries

Souza¹,

Vizarim²,

Reichhardt³

et al. 2022

Preprint

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Using a particle-based model, we examine the collective dynamics of skyrmions interacting with a funnel potential under dc driving as the skyrmion density and relative strength of the Magnus and damping terms are varied. For driving in the easy direction, we find that increasing the skyrmion density reduces the average skyrmion velocity due to jamming of skyrmions near the funnel opening, while the Magnus force causes skyrmions to accumulate on one side of the funnel array. For driving in the hard direction, there is a critical skyrmion density below which the skyrmions become trapped. Above this critical value, a clogging effect appears with multiple depinning and repinning states where the skyrmions can rearrange into different clogged configurations, while at higher drives, the velocity-force curves become continuous. When skyrmions pile up near the funnel opening, the effective size of the opening is reduced and the passage of other skyrmions is blocked by the repulsive skyrmion-skyrmion interactions. We observe a strong diode effect in which the critical depinning force is higher and the velocity response is smaller for hard direction driving. As the ratio of Magnus force to dissipative term is varied, the skyrmion velocity varies in a non-linear and non-monotonic way due to the pile up of skyrmions on one side of the funnels. At high Magnus forces, the clogging effect for hard direction driving is diminished.

show abstract

“…Magnetic skyrmion, 1-3 a particle-like spin structure usually stabilized by Dzyaloshinskii-Moriya (DM) interaction, 4,5 has attracted much interest because of its rich physics [6][7][8] and possible implementations in various devices such as skyrmion diodes, 9,10 skyrmion ratchets, 11 racetrack memories, 12 logic gates, [13][14][15][16] and nano-oscillators. [17][18][19][20][21][22][23][24][25][26][27][28] Among them, nanooscillators based on skyrmions in circular nanodisks have been heavily studied because their high-frequency motion can be easily used for microwave generators and/or detectors.…”

Section: Introductionmentioning

confidence: 99%