Micromagnetic simulations of magnetization reversal in Co/Ni multilayers

Abstract

In this paper, the magnetization reversal process of Co/Ni/Co trilayers was studied using finite element micromagnetic simulations. Demagnetization curves were calculated for a multilayer with a Co layer thickness of 5 nm and an Ni layer thickness of 15 nm. Both the Ni and the Co layer reverse at the same well-defined switching field. A two-step process occurs at interlayer exchange lower than one-third of the bulk value. The transition from a one-step to a two-step reversal process occurs if the anisotropy of Co is considerably high ( K u=450 kJ/m 3). A completely different reversal mechanism occurs if the uniaxial anisotropy of the Co layer approaches 45 kJ/m 3. Now demagnetizing effects override the uniaxial anisotropy.