558 research outputs found
Transition from the macrospin to chaotic behaviour by a spin-torque driven magnetization precession of a square nanoelement
We demonstrate (using full-scale micromagnetic simulations) that the spin
injection driven steady-state precession of a thin magnetic nanoelement exhibit
a complicate transition from the quasi-macrospin to the chaotic behaviour with
the increasing element size. For nanoelement parameters typical for those used
experimentally we have found that the macrospin approximation becomes invalid
already for very small nanoelement sizes (~ 30 nm), in contrast to the
previously reported results (Li and Zhang, Phys. Rev. B, vol. B68, 024404-1
(2003))Comment: Submitted to Phys. Rev.
Chaotic synchronization of coupled electron-wave systems with backward waves
The chaotic synchronization of two electron-wave media with interacting
backward waves and cubic phase nonlinearity is investigated in the paper. To
detect the chaotic synchronization regime we use a new approach, the so-called
time scale synchronization [Chaos, 14 (3) 603-610 (2004)]. This approach is
based on the consideration of the infinite set of chaotic signals' phases
introduced by means of continuous wavelet transform. The complex space-time
dynamics of the active media and mechanisms of the time scale synchronization
appearance are considered.Comment: 11 pages, 7 figures, published in CHAOS, 15 (2005) 01370
Quasi-deterministic transport of Brownian particles in an oscillating periodic potential
We consider overdamped Brownian dynamics in a periodic potential with
temporally oscillating amplitude. We analyze the transport which shows
effective diffusion enhanced by the oscillations and derive approximate
expressions for the diffusion coefficient. Furthermore we analyze the effect of
the oscillating potential on the transport if additionally a constant force is
applied. We show the existence of synchronization regimes at which the
deterministic dynamics is in resonance with the potential oscillations giving
rise to transport with extremely low dispersion. We distinguish slow and fast
oscillatory driving and give analytical expressions for the mean velocity and
effective diffusion.Comment: submitted: Feb 12th, 201
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