Magnetic field dependence of magnetization reversal behavior in Co/Pt multilayers

Magnetic field dependence of magnetization reversal in Co/Pt multilayers has been quantitatively investigated. Serial samples of Co/Pt multilayers have been prepared by dc magnetron sputtering under various Ar pressures. Magnetization reversal was monitored by magnetization viscosity measurement and direct domain observation using a magneto-optical microscope system. The wall-motion speed V and the nucleation rate R were determined using a domain reversal model based on time-resolved domain reversal patterns. Both V and R were found to be exponentially dependent on the reversing applied field. From the exponential dependence, the activation volumes of the wall-motion and nucleation could be determined based on a thermally activated relaxation model. The wall-motion activation volume was revealed to be slightly larger than the nucleation activation volume. (C) 2001 American Institute of Physics.