Damping criteria of magnetization in ferromagnetic ellipsoids

The critical damping constant of the magnetization of a uniformly magnetized ferromagnetic ellipsoid can be expressed by a simple formula based upon the small signal solution of the Landau-Lifshitz-Gilbert equation. It is predicted from the damping criteria that the damping condition of the magnetization in a uniformly magnetized ferromagnetic ellipsoid can be controlled by adjusting the damping constant, shape, anisotropy field, and/or external magnetic bias field, which is confirmed experimentally in thin-film geometry.