Power-law scaling behavior in Barkhausen avalanches of ferromagnetic thin films

Statistical properties of Barkhausen noise in amorphous ferromagnetic films

“…The measured scaling exponents are similar to that obtained for several bulk amorphous magnetic materials and amorphous films in a wide range of thickness, as well as are in quantitative agreement with the predictions of two theoretical models: CZDS model, if dipolar interactions are neglected [54,55], and the UMM model [26,37]. Our films are thinner than ribbons and sheets [31], known to exhibit three-dimensional magnetic behavior, but thicker than previously studied two-dimensional films [42,43,[45][46][47][48][49][50][51][52]. We interpret these results as a clear 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.…”

“…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.…”

“…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…”

“…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].…”

The effects of external noise on threshold induced correlations in ferromagnetic systems

“…The mentioned type of relaxation can cause the extreme events such as avalanches that span almost the whole system leading to a phase transition in the thermodynamic limit [14]. Among these phenomena, magnetization and relaxation processes in ferromagnetic materials play a distinguished role [15][16][17][18][19][20][21][22][23].…”