Simulating rare switching events of magnetic nanostructures with forward flux sampling

Vogler, Christoph; Bruckner, Florian; Bergmair, Bernhard; Huber, Thomas; Suess, Dieter; Dellago, Christoph

doi:10.1103/physrevb.88.134409

Cited by 26 publications

(20 citation statements)

References 35 publications

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“…Here, Q is the configuration space of the underlying system, and A and B are two of its local free energy minima. In recent years, FFS has been used for studying a wide range of rare-event-driven phenomena such as evaporation [18][19][20], coalescence [21], wetting [22], magnetic switching [23], protein folding [24], DNA hybridization [25,26], phase separation in active systems [27], protein aggregation [28] and crystal nucleation [29][30][31][32][33][34][35][36][37][38][39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

Forward-flux sampling with jumpy order parameters

Haji-Akbari

2018

The Journal of Chemical Physics

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Forward-flux sampling (FFS) is a path sampling technique that has gained increased popularity in recent years and has been used to compute rates of rare event phenomena such as crystallization, condensation, hydrophobic evaporation, DNA hybridization, and protein folding. The popularity of FFS is not only due to its ease of implementation but also because it is not very sensitive to the particular choice of an order parameter. The order parameter utilized in conventional FFS, however, still needs to satisfy a stringent smoothness criterion in order to assure sequential crossing of FFS milestones. This condition is usually violated for order parameters utilized for describing aggregation phenomena such as crystallization. Here, we present a generalized FFS algorithm for which this smoothness criterion is no longer necessary and apply it to compute homogeneous crystal nucleation rates in several systems. Our numerical tests reveal that conventional FFS can sometimes underestimate the nucleation rate by several orders of magnitude.

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Section: Introductionmentioning

confidence: 99%

Forward-flux sampling with jumpy order parameters

Haji-Akbari

2018

The Journal of Chemical Physics

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“…The energy barrier calculations is achieved through a numerical technique called Nudged Elastic Band Method [14][15][16] (NEBM), which calculates minimum energy transitions between equilibrium states in magnetic systems. We use an optimised version of the algorithm recently proposed by Bessarab et al 16 since they claim that early versions of the method [17][18][19][20] lead to uncontrolled behaviour of the algorithm. In particular, we are interested on the minimum energy path between two states, since it gives us the smallest energy required, i.e.…”

mentioning

confidence: 99%

Thermal stability and topological protection of skyrmions in nanotracks

Cortés‐Ortuño

Wang

Beg

et al. 2017

Sci Rep

145

142

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Magnetic skyrmions are hailed as a potential technology for data storage and other data processing devices. However, their stability against thermal fluctuations is an open question that must be answered before skyrmion-based devices can be designed. In this work, we study paths in the energy landscape via which the transition between the skyrmion and the uniform state can occur in interfacial Dzyaloshinskii-Moriya finite-sized systems. We find three mechanisms the system can take in the process of skyrmion nucleation or destruction and identify that the transition facilitated by the boundary has a significantly lower energy barrier than the other energy paths. This clearly demonstrates the lack of the skyrmion topological protection in finite-sized magnetic systems. Overall, the energy barriers of the system under investigation are too small for storage applications at room temperature, but research into device materials, geometry and design may be able to address this.

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“…In particular we present a series of M H hysteresis loops calculated at constant sweep rate over a range of coupling constants to examine the effect of the exchange parameter and sweep rate on the M H hysteresis loops. This work compliments and extends previous studies of dual-grain-reversal energy landscapes 23 and formulations of the dual-grain attempt frequency, 19,24 and serves as an precursor to our formulation and application of the combined MEP-KMC algorithm to study interacting N×N×2 ECC thin films which includes both magnetostatic and intralayer exchange interactions. 25 In the following section, we discuss the energy landscapes for a dual layer grain, which we model as a system consisting of two coupled Stoner-Wohlfarth particles (SWPs) in a magnetic field.…”

Section: Introductionmentioning

confidence: 55%

Thermally activated switching at long time scales in exchange-coupled magnetic grains

et al. 2015

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Rate coefficients of the Arrhenius-Néel form are calculated for thermally activated magnetic moment reversal for dual layer exchange-coupled composite (ECC) media based on the Langer formalism and are applied to study the sweep rate dependence of M H hysteresis loops as a function of the exchange coupling I between the layers. The individual grains are modelled as two exchange coupled Stoner-Wohlfarth particles from which the minimum energy paths connecting the minimum energy states are calculated using a variant of the string method and the energy barriers 2

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Simulating rare switching events of magnetic nanostructures with forward flux sampling

Cited by 26 publications

References 35 publications

Forward-flux sampling with jumpy order parameters

Forward-flux sampling with jumpy order parameters

Thermal stability and topological protection of skyrmions in nanotracks

Thermally activated switching at long time scales in exchange-coupled magnetic grains

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