Observation of ice-rule violation and monopole dynamics via edge nucleation of domain walls in artificial spin ice lattice

Krishnia, Sachin; Purnama, Indra; Lew, Wen Siang

doi:10.1016/j.jmmm.2016.07.005

Cited by 9 publications

(12 citation statements)

References 32 publications

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“…Such functional form has been fitted theoretically to the memristors introduced in 38 , under the assumption of spin-like islands of an artificial spin ice. The mechanism which induced the memristor feedback in the ASI approximation was a current-induced domain wall formation which is well documented in the literature [44][45][46][47] . However, real magnetic materials have complicated dynamical behavior of the magnetization, many-body effects not captured by a simple Ising-like variable, and an interaction with the current captured by the Zhang-Li coupling 43 and temperature effects which can be attributed to thermistors 50 .…”

mentioning

confidence: 79%

Memristive effects in nanopatterned permalloy Kagomé array

Fonseca¹,

García²,

Caravelli³

et al. 2022

Preprint

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We study memristive effects in Kagomé nanopatterned permalloy. We observe that at low frequencies a thermistor effect is present, a phenomenon arising due to the lithography and absent in similar experiments for thin films. However, we also show via an independent anisotropic magnetoresistive study that a small hysteresis accounting for 1% of the effect is not attributable to a thermistive effect. Such effect is also confirmed by a careful subtraction scheme between nearby thermal hysteresis. In the millihertz regime, an effective model is provided to describe the experimental results for the thermistor, showing that there should be a crossover from the millihertz to the gigahertz, from a thermistor to an memresistive effect for nanopatterned permalloy.

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mentioning

confidence: 79%

Memristive effects in nanopatterned permalloy Kagomé array

Fonseca¹,

García²,

Caravelli³

et al. 2022

Preprint

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“…Such a "left-bending boomerang" feature 7 in the corresponding M-FORC distribution is typically associated with systems that exhibit domain nucleation and abrupt propagation [33], where domain growth is dominated by a strong exchange interaction [29]. Due to the presence of the exchange and dipolar interaction, the magnetization reversal in the spin-ice system usually takes place via DW nucleation from the sample edges, and propagate through the interconnections to form the Dirac strings [8,9,18]. For the FORC curves with Hr > -330 Oe, the onset of the up-switching field is almost independent of Hr, as indicated by the vertical dashed line in the inset in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…For the field along one of the branches in the spin ice structure, i.e. =0°, the loops show a single-step of the avalanche-like switching behavior [8,9,18]. When the field orientation is away from the directions of branches and close to the orthogonal direction of one of the three branches, the MOKE loops show a clear two-step feature.…”

Section: Introductionmentioning

confidence: 98%

Magnetization reversal in kagome artificial spin ice studied by first-order reversal curves

et al. 2017

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Magnetization reversal of interconnected Kagome artificial spin ice was studied by the first-order reversal curve (FORC) technique based on the magneto-optical Kerr effect and magnetoresistance measurements. The magnetization reversal exhibits a distinct six-fold symmetry with the external field orientation. When the field is parallel to one of the nano-bar branches, the domain nucleation/propagation and annihilation processes sensitively depend on the field cycling history and the maximum field applied. When the field is nearly perpendicular to one of the branches, the FORC measurement reveals the magnetic interaction between the Dirac strings and orthogonal branches during the magnetization reversal process.Our results demonstrate that the FORC approach provides a comprehensive framework for understanding the magnetic interaction in the magnetization reversal processes of spinfrustrated systems.

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“…It has also been proposed that the use of heat generated by metal strip lines adjacent to two sides of a square lattice can be used to create unidirectional currents [26]. Other possible avenues to produce controlled injection of monopole currents include the incorporation of topological defects in an artificial square ice [27] and the use of domain walls in connected artificial kagome ice [28]. However, despite the many experimental attempts, there has not been a well-defined scheme to control the location, generation, and directionality of monopole currents [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Control of emergent magnetic monopole currents in artificial spin ice

et al. 2020

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The control of emergent magnetic monopoles for the generation of monopole currents in artificial spin ice is essential for their use in nanomagnet-based device applications. Here we present a scheme to inject monopole currents into an artificial square ice at specific locations, which provides a means to control the propagation of the generated emergent monopole currents. Specifically, we modify an artificial square ice by populating two of its edges with different vertex configurations consisting of two, three, and four nanomagnets meeting at a common point. After setting an initial state with a global magnetic field, injection of monopoles occurs at one of the edges where the vertices have higher switching probability. We experimentally observe this vertex-specific nucleation of emergent magnetic monopoles using x-ray photoemission electron microscopy. Additionally, we demonstrate that a lateral shift in the reversal of the magnets, leading to the formation of large domains, is consistent with theoretical simulations incorporating higher-order contributions in the magnetic Hamiltonian. Finally, we find a strong correlation between the location of emergent monopole injection and the film thickness, which is a result of the switching probability associated with the different vertex configurations.

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Observation of ice-rule violation and monopole dynamics via edge nucleation of domain walls in artificial spin ice lattice

Cited by 9 publications

References 32 publications

Memristive effects in nanopatterned permalloy Kagomé array

Memristive effects in nanopatterned permalloy Kagomé array

Magnetization reversal in kagome artificial spin ice studied by first-order reversal curves

Control of emergent magnetic monopole currents in artificial spin ice

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