The nonlinear behavior of single spherical particles and many-particle ensembles under an external oscillating magnetic field was studied using the Landau-Lifshitz-Gilbert approach. The exact analytical formulae for calculating field frequency and the dependence of the configuration of the initial moment on the system mean magnetization were obtained. Using asymptotic decomposition we obtained simple expressions for describing the nonlinear dynamics of spherical particles in the cases of large and small frequencies. These solutions are in good agreement with numerical calculations of the Landau-Lifshitz-Gilbert equation for the considering systems.
75.10.Hk Classical spin models
75.75.+a Magnetic properties of nanostructures
85.75.-d Magnetoelectronics; spintronics: devices exploiting spin polarized transport or integrated magnetic fields
$^1$Department of General Physics, Faculty of Physics, Moscow State University, Moscow, 119991, Russia
$^2$Institute of Control Sciences, Russian Academy of Sciences, Moscow, 117997, Russia
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