Quantitative correlation between the local coercivity variation and magnetization reversal dynamics in Co/Pd multilayer thin films

Abstract

We report the existence of a quantitative correlation between magnetization reversal dynamics and spatial variation of the local coercivity, ΔHC, in Co/Pd multilayer thin films. The ΔHC was directly probed by measuring hysteresis loops on spatially resolved local regions by means of a magneto-optical microscope magnetometer and magnetization reversal dynamics was characterized by analyzing the wall-motion speed V and the nucleation rate R. We found a linear relationship between log(V/R) and log(ΔHC), where a small variation of the local coercivity results in a large V/R showing wall-motion dominant reversal behavior. A Monte Carlo simulation considering magnetic nonuniformity well predicts the observed experimental relationship.