Barkhausen statistics from a single domain wall in thin films studied with ballistic Hall magnetometry

Abstract

The movement of a micron-size section of an individual domain wall in a uniaxial garnet film was studied using ballistic Hall micromagnetometry. The wall propagated in characteristic Barkhausen jumps, with the distribution in jump size S, following the power-law relation, D͑S͒ ϰ S −. In addition to reporting on the suitability of employing this alternative technique, we discuss the measurements taken of the scaling exponent , for a single domain wall in a two-dimensional sample with magnetization perpendicular to the surface, and low pinning center concentration. This exponent was found to be 1.14± 0.05 at both liquid helium and liquid nitrogen temperatures.

Simulation of the Magnetic Hysteresis Loop in Ferrimagnetism

“…Since the spin valve 13) by Fe 3 O 4 has a complex structure, essential understanding of the magnetization process is not sufficient. In this paper, our aim is to build a theory of magnetization process for spin valve of Fe 3 O 4 as a ferrimagnetic material and derive the magnetic hysteresis loop with various parameter by the computer simulation using retarded trace method.…”

Avalanche spatial structure and multivariable scaling functions: Sizes, heights, widths, and views through windows

“…Many of these systems exhibit avalanches which have power law size distributions. These include Barkhausen noise in ferromagnets [4][5][6][7][8], fluid imbibition into porous media, flux-line depinning [3,[9][10][11][12][13], and martensitic transformations [14,15], to name a few. In the first three of these systems, avalanches are the result of the jerky motion of an interface (domain wall, fluid front, flux line) in a disordered environment, and can be described by the same family of front-propagation models.…”

Hall micromagnetometry of domain-wall depinning in Permalloy nanowires

“…All experiments presented here are carried out using such notches with a triangular geometry. In soft-magnetic nanowires with submicron width and thicknesses of some 10 [13,17]. Transitions between these metastable states are possible, e.g., by depinning a DW from a notch [13] or interaction with spin-polarized currents [18].…”

“…Our Hall sensors allow to identify the presence of an individual DW via detecting its stray field in a region of about 1 mm 2 [8]. It has been demonstrated that the technique is sufficiently sensitive to track the motion of magnetization in the Peierls potential with subatomic resolution [9] and to measure the Barkhausen statistics of a single DW in garnet films [10]. The micromagnetic configuration of the ferromagnetic specimens is not affected by the Hall measurements due to the low susceptibility of the semiconductor heterostructure.…”