Analysis of spanning avalanches in the two-dimensional nonequilibrium zero-temperature random-field Ising model

Spasojević, Djordje; Janićević, Sanja; Knežević, Milan

doi:10.1103/physreve.89.012118

Cited by 32 publications

(29 citation statements)

References 28 publications

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“…Disordered ferromagnetic films exhibiting criticality at the hysteresis loop [4,11,[16][17][18] are conveniently modeled by two-dimensional random-field Ising model (2D-RFIM) [19][20][21], as described in Section II. Besides, these model systems are also of high importance for theoretical considerations for the following reasons.…”

Section: Introductionmentioning

confidence: 99%

Dynamical implications of sample shape for avalanches in 2-dimensional random-field Ising model with saw-tooth domain wall

Tadić

2018

Physica A: Statistical Mechanics and its Applications

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We study dynamics of a built-in domain wall (DW) in 2-dimensional disordered ferromagnets with different sample shapes using random-field Ising model on a square lattice rotated by 45 degrees. The saw-tooth DW of the length L x is created along one side and swept through the sample by slow ramping of the external field until the complete magnetisation reversal and the wall annihilation at the open top boundary at a distance L y . By fixing the number of spins N = L x × L y = 10 6 and the random-field distribution at a value above the critical disorder, we vary the ratio of the DW length to the annihilation distance in the range L x /L y ∈ [1/16, 16]. The periodic boundary conditions are applied in the y-direction so that these ratios comprise different samples, i.e., surfaces of cylinders with the changing perimeter L x and height L y . We analyse the avalanches of the DW slips between following field updates, and the multifractal structure of the magnetisation fluctuation time series. Our main findings are that the domain-wall lengths materialised in different sample shapes have an impact on the dynamics at all scales. Moreover, the domain-wall motion at the beginning of the hysteresis loop (HLB) probes the disorder effects resulting in the fluctuations that are significantly different from the large avalanches in the central part of the loop (HLC), where the strong fields dominate. Specifically, the fluctuations in HLB exhibit a wide multi-fractal spectrum, which shifts towards higher values of the exponents when the DW length is reduced. The distributions of the avalanches in this segments of the loops obey power-law decay and the exponential cutoffs with the exponents firmly in the mean-field universality class for long DW. In contrast, the avalanches in the HLC obey Tsallis density distribution with the power-law tails which indicate the new categories of the scale invariant behaviour for different ratios L x /L y . The large fluctuations in the HLC, on the other hand, have a rather narrow spectrum which is less sensitive to the length of the wall. These findings shed light to the dynamical criticality of the random-field Ising model at its lower critical dimension; they can be relevant to applications of the dynamics of injected domain walls in two-dimensional nanowires and ferromagnetic films.

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Section: Introductionmentioning

confidence: 99%

Dynamical implications of sample shape for avalanches in 2-dimensional random-field Ising model with saw-tooth domain wall

Tadić

2018

Physica A: Statistical Mechanics and its Applications

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“…1, sequence a-b-c that corresponds to increasing field values). When disorder aproaches its critical value σ c , there is a peak in the average number of 1d spanning avalanches [19] (See Fig. 1, sequence d-e-f).…”

Section: Iii1 Periodic Boundary Conditions (Pbc)mentioning

confidence: 99%

“…[19], instead of the standard choice (σ − σ c ) /σ c . This issue was already proposed in the first works on the RFIM [12] and was extensively discussed in [20].…”

Section: Iii1 Periodic Boundary Conditions (Pbc)mentioning

confidence: 99%

“…Recently, D.Spasojević and coworkers found numerical evidence of a critical point, below which (σ < σ c ) the system orders ferromagnetically. These evidences were based on the FSS collapse of the curves corresponding to magnetization [17], distribution of avalanche sizes [18] and number of spanning avalanches [19].…”

Section: Introductionmentioning

confidence: 99%

“…In order to study the effect of the aspect ratio and boundary conditions in universal FSS functions we will focus on the number of spanning avalanches in one direction [19] [20]. Spanning avalanches, strictly speaking, are well defined objects only in finite size simulations with square or rectangular boundaries.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of the aspect ratio and boundary conditions on universal finite-size scaling functions in the athermal metastable two-dimensional random field Ising model

Navas-Portella

Vives

2016

Phys. Rev. E

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This work studies universal finite size scaling functions for the number of 1d spanning avalanches in a two-dimensional disordered system with boundary conditions of different nature and different aspect ratios. For this purpose, we consider the 2d Random Field Ising Model at T = 0 driven by the external field H with athermal dynamics implemented with periodic and forced boundary conditions. We choose a convenient scaling variable z that accounts for the deformation of the distance to the critical point caused by the aspect ratio. Moreover, assuming that the dependence of the finite size scaling functions on the aspect ratio can be accounted by an additional multiplicative factor, we have been able to collapse data for different system sizes, different aspect ratios and different nature of the boundary conditions into a single scaling functionQ.

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Breakdown of Barkhausen Criticality in an Ultrathin Ferromagnetic Film

Roy

Kumar

2020

J Supercond Nov Magn

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Analysis of spanning avalanches in the two-dimensional nonequilibrium zero-temperature random-field Ising model

Cited by 32 publications

References 28 publications

Dynamical implications of sample shape for avalanches in 2-dimensional random-field Ising model with saw-tooth domain wall

Dynamical implications of sample shape for avalanches in 2-dimensional random-field Ising model with saw-tooth domain wall

Influence of the aspect ratio and boundary conditions on universal finite-size scaling functions in the athermal metastable two-dimensional random field Ising model

Breakdown of Barkhausen Criticality in an Ultrathin Ferromagnetic Film

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