Dynamics of topological defects in a two-dimensional magnetic domain stripe pattern

Abstract

Two dimensional magnetic films with perpendicular magnetization spontaneously form magnetic domain patterns that evolve or undergo symmetry transformations as a function of temperature. When the system is driven from equilibrium by a rapid change in temperature, topological pattern defects are the elementary pattern excitations that affect this evolution. An elastic continuum model is adapted to describe how a metastable population of topological defects alters the domain density and the magnetic susceptibility of the "stripe" magnetic domain pattern. Temporal changes in the susceptibility are interpreted using a dynamical equation describing the defect population. Recent experiments provide a quantitative verification of the model, and illustrate the use of the magnetic susceptibility to follow the population dynamics of topological defects in this system, and its potential role in investigating a pattern melting phase transition.PACS numbers:

Monte Carlo simulation of the effects of higher-order anisotropy on the spin reorientation transition in the two-dimensional Heisenberg model with long-range interactions

“…The authors note that near to the SRT, quadratic coupling alone is not sufficient to account for this mixed behavior. Using AC susceptibility studies of striped phases in Fe/Ni films by Abu-Libdeh et al [36,37,57], have also indicated the presence of long time scale dynamics. By varying the order of anisotropy we wish to investigate the nature of the phase transition between the striped and in plane phases.…”

“…The width and mobility of stripes depends on temperature [35]. In particular these can systems display strong thermal memory, in which the domain configuration depend on the rate of heating or cooling [36,37]. Both the reorientation and stripe melting transitions have been studied analytically [38,39,40,41] and using Monte Carlo Simulation [42,43].…”

Controlled nucleation of topological defects in the stripe domain patterns of lateral multilayers with perpendicular magnetic anisotropy

“…It has been shown 26 that the consequences of the PMA-MLM fabrication process are to create an in-plane shape anisotropy and, also, to introduce "edges" within the continuous layer in which topological defects could be nucleated (e.g., 1 2 vortices in the in-plane magnetization or grain boundaries within the magnetic stripe pattern). A good control of the essential parameters needed for nucleation of these topological defects would open the route to understand defect interactions on an individual basis (in contrast with previous statistical studies in disordered patterns 6,9,[12][13][14][15] ) and, also, to study the physics of nucleation and propagation of the observed fractional topological defects (coupled 1 2 disclination -1 2 vortex) which is interesting for magnetic logic devices. 20,35 However, in Ref.…”

“…6,7 Defects such as dislocations, 8 disclinations, 7 grain boundaries, 9 or even skyrmions 10,11 have been observed. These topological defects play an important role in magnetization reversal processes and magnetization dynamics of PMA materials [12][13][14] and, also, in the physics of phase transitions in 2D modulated phases. 5,15 However, the experimental study of these topological defects in PMA materials has been hindered by the problems to control their nucleation in extended samples since they usually occur within very disordered labyrinthine configurations.…”

Antipersistent behavior of defects in a lyotropic liquid crystal during annihilation

“…One of the main aspects of the ordering process is the dynamical behavior of defects present in the material. Topological defects appear in several systems that present some kind of ordering [12][13][14][15][16][17]. Alloys [18], semiconductors [19], polymers [20] and liquid crystals [21,22] are just a few examples.…”