Switching volumes in high-density recording materials with different magnetization reversal modes

The switching volume of materials for recording media is obtained from measurements of the time dependence of the magnetization, and related to the magnetization reversal mode. The switching, or activation, volume is large and close to the physical size in particles with reversal similar to coherent rotation, and it decreases when the reversal is incoherent or heterogeneous, or, with larger extent, in materials switching the magnetization by nucleation. (C) 1999 Elsevier Science B.V. All rights reserved.