3,361 research outputs found
On the local nature and scaling of chaos in weakly nonlinear disordered chains
The dynamics of a disordered nonlinear chain can be either regular or chaotic
with a certain probability. The chaotic behavior is often associated with the
destruction of Anderson localization by the nonlinearity. In the presentwork it
is argued that at weak nonlinearity chaos is nucleated locally on rare resonant
segments of the chain. Based on this picture, the probability of chaos is
evaluated analytically. The same probability is also evaluated by direct
numerical sampling of disorder realizations and quantitative agreement between
the two results is found
Controlling skyrmion bubble confinement by dipolar interactions
Large skyrmion bubbles in confined geometries of various sizes and shapes are
investigated, typically in the range of several micrometers. Two fundamentally
different cases are studied to address the role of dipole-dipole interactions:
(I) when there is no magnetic material present outside the small geometries and
(II) when the geometries are embedded in films with a uniform magnetization. It
is found that the preferential position of the skyrmion bubbles can be
controlled by the geometrical shape, which turns out to be a stronger influence
than local variations in material parameters. In addition, independent
switching of the direction of the magnetization outside the small geometries
can be used to further manipulate these preferential positions, in particular
with respect to the edges. We show by numerical calculations that the observed
interactions between the skyrmion bubbles and structure edge including the
overall positioning of the bubbles are fully controlled by dipole-dipole
interactions
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