Barkhausen noise from zigzag domain walls

Cerruti, Benedetta; Zapperi, Stefano

doi:10.1088/1742-5468/2006/08/p08020

Cited by 10 publications

(13 citation statements)

References 31 publications

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“…In addition, the exponent for the case without dipolar interactions is close to the theoretically expected value of τ ≃ 1 for the 1 + 1 dimensional interface depinning of the short range interaction universality class [10], [11]. When the strength of the dipolar interactions is increased, we observe a crossover to a different exponent value, close to the value reported for a lattice model for zigzag domain walls [12]. By inspecting the domain wall morphology in Fig.…”

Section: Modelsupporting

confidence: 86%

Effect of Dipolar Interactions for Domain-Wall Dynamics in Magnetic Thin Films

et al. 2010

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We study the effect of long range dipolar forces on the dynamics and morphology of domain walls in magnetic thin films by numerical simulations of the spin-1 random field Ising model. By studying the size distribution of avalanches of domain wall motion arising as a response to quasistatic external driving, we observe a cross-over from the case dominated by short range interactions to another universality class where the long range dipolar forces become important. This crossover is accompanied with a change of the domain wall morphology from a rough wall to walls with zigzag structure.

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Section: Modelsupporting

confidence: 86%

Effect of Dipolar Interactions for Domain-Wall Dynamics in Magnetic Thin Films

et al. 2010

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“…22). A similar value of the critical exponent was predicted for the charged zigzag domain wall 26 . On the other hand, for large |q| or small M 2 S , the shortrange domain-wall surface tension is dominant and the interaction kernel is described by J (q) ∝ q 2 , in which a class with the critical exponent of τ = 1 is predicted, as observed in general elastic interfaces 15,27 .…”

supporting

confidence: 73%

Tunable scaling behaviour observed in Barkhausen criticality of a ferromagnetic film

2007

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A ferromagnetic material shows a sequence of discrete and jerky domain jumps, known as the Barkhausen avalanche 1,2 , in the presence of an external magnetic field. Studies of Barkhausen avalanches reveal power-law scaling behaviour that suggests an underlying criticality 3-8 , as observed in a wide variety of systems such as superconductor vortices 9 , microfractures 10 , earthquakes 11 , lung inflations 12 , mass extinctions 13 , financial markets 14 and charge-density waves 15 . The most interesting unsolved fundamental question is whether the universality in the scaling exponent holds regardless of the material and its detailed microstructure. Here we show that the scaling behaviour of Barkhausen criticality in a given ferromagnetic film is experimentally tunable by varying the temperature (not dimensionality). We observe for the first time that the scaling behaviour in the Barkhausen criticality of a given system crosses over between two universality classes when the relative contributions from the dipolar interaction and domain-wall energies are altered by an experimental parameter.All theoretical works so far predict that the universality of the scaling exponent depends only on the dimensionality of a system, even though the value of the scaling exponent varies according to the theory [16][17][18][19][20][21][22] . However, the measured scaling exponents reported in the literature span a relatively wide range of values despite the same dimensionality 3-8 . Thus, the universality has been questioned, and our understanding is far from complete. To test the validity of the universality of Barkhausen criticality, a desirable approach is to make systematic measurements of the scaling exponent under well-controlled experimental conditions with reliable statistics in a given system while maintaining the same dimensionality. A ferromagnetic (FM) MnAs film on GaAs(001) substrate is considered an ideal system for such purposes: it reveals a systematic variation of domain-evolution patterns with temperature during a Barkhausen avalanche, a variation that results from the decrease in the saturation magnetization M S with temperature 23 . Thus, scaling behaviour in different domain-evolution patterns in a given system can be investigated in an experimentally controllable manner. Figure 1 shows representative domain-evolution patterns of the 50 nm MnAs film observed three consecutive times by means of a magneto-optical microscope magnetometer (MOMM) at each designated temperature in a range of 20−35 • C. In Fig. 1, we can clearly see that the domain evolution patterns at each temperature show a sequence of discrete and jerky domain jumps during the magnetization reversal. Also, we found that the domain jumps proceed with randomness of interval, size and location for the repeated experiments, as clearly seen from the three representative domain images at each temperature. From this evidence, it Figure 1 Representative domain-evolution patterns at several temperatures in the temperature range of 20−35 • C. These pattern...

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“…Summarizing the theoretical predictions, for three-dimensional systems with the dynamics governed by long-range interactions, the scaling exponents are τ = 1.50, α = 2.0 and 1/σνz = 2 [54,55], while for systems governed by short-range interactions and same dimensionality, τ = 1.27, α = 1.5 and 1/σνz = 1.77 [36,37,54,55]. On the other side, for two-dimensional systems, although there is not a complete agreement between theoreticians on the real values, the models indicate τ ∼ 1.33, α ∼ 1.5 and 1/σνz ∼ 1.5 for the long-range interaction problem [32][33][34]77], while τ ∼ 1.06 for the short-range interaction one [36,37,77]. In the last case, α and 1/σνz are still not predicted.…”

Section: B Barkhausen Noise and Statistical Propertiesmentioning

confidence: 94%

“…For two-dimensional systems and samples with reduced dimensions, the BN statistical properties are less clear. On the theoretical side, models and simulations [32][33][34][35][36][37][38][39][40][41] infer the existence of two distinct universality classes, according the range of interactions governing the DWs dynamics, as well as indicate that three and two-dimensional systems present distinct exponents.…”

Section: Introductionmentioning

confidence: 99%

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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Barkhausen noise from zigzag domain walls

Cited by 10 publications

References 31 publications

Effect of Dipolar Interactions for Domain-Wall Dynamics in Magnetic Thin Films

Effect of Dipolar Interactions for Domain-Wall Dynamics in Magnetic Thin Films

Tunable scaling behaviour observed in Barkhausen criticality of a ferromagnetic film

Statistical properties of Barkhausen noise in amorphous ferromagnetic films

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