Two-dimensional critical scaling behavior of Barkhausen avalanches (invited)

Shin, Sung‐Chul; Ryu, Kwang-Su; Kim, Dong-Hyun; Akinaga, H.

doi:10.1063/1.2830967

Cited by 15 publications

(36 citation statements)

References 27 publications

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“…D.-H. Kim et al [45] have presented τ ∼ 1.33 for Co polycrystalline films, with thicknesses varying from 5 to 50 nm, and S.-C. Shin et al [46] have found τ ∼ 1.33 for Co and MnAs films, with the same thicknesses, by measurements using a magneto-optical microscope magnetometer, capable of observing directly the motion of the DWs and the Barkhausen avalanches [47]. Following the same line, K.-S. Ryu et al [48,49] have shown for a 50 nm-thick MnAs film the crossover between two distinct universality classes, which is caused by the competition between longrange dipolar interaction and the short-range DW surface tension, with τ varying from 1.32 to 1.04, tuned by an increase of temperature from 20…”

Section: Introductionmentioning

confidence: 56%

“…Considering these reports found in literature based on magneto-optical measurements [42][43][44][45][46][47][48][49][50][51][52], although they restrict the analysis to distributions of jump sizes, when compared to theoretical predictions, most of them does confirm an essentially two-dimensional magnetic behavior for films, as expected due to reduced thickness of the studied samples.…”

Section: Introductionmentioning

confidence: 99%

“…Experimentally, several interesting results have been obtained for different ferromagnetic films through both magneto-optical [42][43][44][45][46][47][48][49][50][51][52] and inductive [6,8,53] [44], both results obtained through measurements performed using a magneto-optical elipsometer. D.-H. Kim et al [45] have presented τ ∼ 1.33 for Co polycrystalline films, with thicknesses varying from 5 to 50 nm, and S.-C. Shin et al [46] have found τ ∼ 1.33 for Co and MnAs films, with the same thicknesses, by measurements using a magneto-optical microscope magnetometer, capable of observing directly the motion of the DWs and the Barkhausen avalanches [47].…”

Section: Introductionmentioning

confidence: 99%

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Statistical properties of Barkhausen noise in amorphous ferromagnetic films

et al. 2014

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We investigate the statistical properties of the Barkhausen noise in amorphous ferromagnetic films with thicknesses in the range between 100 and 1000 nm. From Barkhausen noise time series measured with the traditional inductive technique, we perform a wide statistical analysis and establish the scaling exponents τ , α, 1/σνz, and ϑ. We also focus on the average shape of the avalanches, which gives further indications on the domain wall dynamics. Based on experimental results, we group the amorphous films in a single universality class, characterized by scaling exponents τ ∼ 1.27, α ∼ 1.5, 1/σνz ∼ ϑ ∼ 1.77, values similar to that obtained for several bulk amorphous magnetic materials. Besides, we verify that the avalanche shape depends on the universality class. By considering the theoretical models for the dynamics of a ferromagnetic domain wall driven by an external magnetic field through a disordered medium found in literature, we interpret the results and identify an experimental evidence that these amorphous films, within this thickness range, present a typical three-dimensional magnetic behavior with predominant short-range elastic interactions governing the domain wall dynamics. Moreover, we provide experimental support for the validity of a general scaling form for the average avalanche shape for non-mean-field systems.

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Section: Introductionmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Statistical properties of Barkhausen noise in amorphous ferromagnetic films

et al. 2014

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“…Controlled injection and motion of domain walls in planar magnetic wires and ferroic nanowires are of a renewed interest for the applications in new memory devices and domain-wall logic [1][2][3]. Techniques to inject a domain wall have been developed in technologically interesting materials as ferromagnetic films [4] and planar Permalloy nanowires [5][6][7] as well as in ferroelectric thin films [3,8]. The motion of the wall in these systems results from an interplay between the applied external field and pinning at intrinsic defects and the morphology of the sample boundary.…”

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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“…Up to now, studies were limited to the low velocity regime (a few tens of µm s −1 ) observed under application of a magnetic field close to the coercive field where DW propagation is governed by pinning defects [12][13][14]. In particular, a magnetization reversal study reported on the temperature dependent critical scaling behavior of Barkhausen avalanches [14,15]. This dependency was ascribed to the decrease of the saturation magnetization with temperature due to the magneto-structural phase coexistence of the ferromagnetic α MnAs phase and the non-ferromagnetic β MnAs phase in the 280-330 K temperature interval.…”

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confidence: 99%