Dynamics and energy dissipation of a rigid dipole driven by the RF-field in a viscous fluid: Deterministic approach.

The deterministic rotation of a ferromagnetic nanoparticle in a fluid is considered. The heating arising from viscous friction of a nanoparticle driven by circularly and linearly polarized alternating magnetic fields is investigated. Since the power loss of such fields depends on the character of the induced motion of a nanoparticle, all types of particle trajectories are described in detail.

Energy dissipation of rigid dipoles in a viscous fluid under the action of a time-periodic field: The influence of thermal bath and dipole interaction.

Ferrofluid heating by an external alternating field is studied based on the rigid dipole model, where the magnetization of each particle in a fluid is supposed to be firmly fixed in the crystal lattice. Equations of motion, employing Newton's second law for rotational motion, the condition of rigid body rotation, and the assumption that the friction torque is proportional to angular velocity are used. This oversimplification permits us to expand the model easily: to take into account the thermal noise and interparticle interaction that allows us to estimate from unified positions the role of thermal activation and dipole interaction in the heating process.

Temperature effects on drift of suspended single-domain particles induced by the Magnus force.

We study the temperature dependence of the drift velocity of single-domain ferromagnetic particles induced by the Magnus force in a dilute suspension. A set of stochastic equations describing the translational and rotational dynamics of particles is derived, and the particle drift velocity that depends on components of the average particle magnetization is introduced. The Fokker-Planck equation for the probability density of magnetization orientations is solved analytically in the limit of strong thermal fluctuations for both the planar rotor and general models.

Rotational properties of ferromagnetic nanoparticles driven by a precessing magnetic field in a viscous fluid.

We study the deterministic and stochastic rotational dynamics of ferromagnetic nanoparticles in a precessing magnetic field. Our approach is based on the system of effective Langevin equations and on the corresponding Fokker-Planck equation. Two key characteristics of the rotational dynamics, namely the average angular frequency of precession of nanoparticles and their average magnetization, are of interest.

Switching properties of ferromagnetic nanoparticles driven by a circularly polarized magnetic field.

We present a comprehensive study of the magnetization switching of a uniaxial nanoparticle driven by a circularly polarized magnetic field rotated in the plane perpendicular to the easy axis. The conditions for the existence of the uniform and non-uniform precessions of the nanoparticle magnetic moment are derived. In addition, the differences between switchings via uniform and non-uniform precession are determined, and the essential role of field polarization is demonstrated.