253 research outputs found
Field sweep rate dependence of magnetic domain patterns: Numerical simulations for a simple Ising-like model
We study magnetic domain patterns in ferromagnetic thin films by numerical
simulations for a simple Ising-like model. Magnetic domain patterns after
quench demonstrate various types of patterns depending on the field sweep rate
and parameters of the model. How the domain patterns are formed is shown with
use of the number of domains, the domain area, and domain area distributions as
well as snapshots of domain patterns. Considering the proper time scale of the
system, we propose a criterion for the structure of domain patterns.Comment: 11 pages, 7 figure
Fast forward of adiabatic control of tunneling states
By developing the preceding work on the fast forward of transient phenomena
of quantum tunneling by Khujakulov and Nakamura (Phys. Rev. {\bf A 93}, 022101
(2016) ), we propose a scheme of the exact fast forward of adiabatic control of
stationary tunneling states with use of the electromagnetic field. The idea
allows the acceleration of both the amplitude and phase of wave functions
throughout the fast-forward time range. The scheme realizes the fast-forward
observation of the transport coefficients under the adiabatically-changing
barrier with the fixed energy of an incoming particle. As typical examples we
choose systems with (1) Eckart's potential with tunable asymmetry and (2)
double -function barriers under tunable relative height. We elucidate
the driving electric field to guarantee the stationary tunneling state during a
rapid change of the barrier and evaluate both the electric-field-induced
temporary deviation of transport coefficients from their stationary values and
the modulation of the phase of complex scattering coefficientsComment: 15 pages, 8 figure
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