Contribution of the Magnetic Field of Eddy Currents to the Gilbert Damping Parameter

Abstract

We study the role of the magnetic field of eddy currents, which are induced in conducting single-domain particles of spherical form, in the magnetization dynamics. To describe the dynamic behavior of magnetization and electromagnetic field generating by the time-dependent magnetization, we use the coupled system of the Landau-Lifshitz-Gilbert (LLG) and Maxwell equations. Assuming that the magnetization direction depends on time in an arbitrary way, we find the solution of the Maxwell equations in the quasi-stationary approximation and calculate the averaged (over the particle volume) magnetic field of eddy currents. Considering this field as an extra contribution to the effective magnetic field acting on the particle magnetic moment, we derive the LLG equation in which the influence of eddy currents is completely accounted for by introducing an additional Gilbert damping parameter of electrodynamic origin.

Keywords

• Conducting single-domain particles
• Landau-Lifshitz-Gilbert equation
• Maxwell equations
• Quasi-stationary approximation
• Eddy currents
• Gilbert damping paramete