Domain reversal dynamics in ferromagnetic thin films of Co/Pd nanomultilayers

Abstract

Domain reversal dynamics in ferromagnetic thin Films has been quantitatively investigated by means of a magneto-optical microscope magnetometer (MOMM), capable of grabbing domain reversal patterns in real time under an applied magnetic field and of measuring local magnetic properties with 400-nm spatial resolution. The domain reversal behavior sensitively changed between wall-motion and nucleation-dominant behavior with changing multilayer structure of the Co/Pd multi-layers. Quantitative analysis revealed that the contrasting reversal behavior was mainly caused by a sensitive change in wall-motion speed and that the reversal ratio of wall-motion speed over nucleation rate was a governing parameter for the contrasting domain reversal dynamics. The activation volumes of the wall-motion and nucleation processes were generally unequal. and the inequality was closely related with the domain dynamics. Based on a Monte-Carlo simulation, both the macroscopic magnetic properties and the local magnetic variation were responsible for the contrasting domain reversal behavior.