Coercive force calculation of ferromagnetic bilayer

A domain wall structure of a strongly coupled ferromagnetic bilayer was proposed. Based on the proposed domain wall structure, the interface wall width and coercive force of coupled 10 nm thick Co/NiFe and Co/Fe bilayers were calculated by minimizing the Néel wall energy. It was found that the coercive force of the Co/NiFe bilayer linearly decreases with increasing thickness ratio of NiFe to total thickness, followed by a rapid drop when the thickness ratio approaches the unit. A linear relation between coercive force and thickness ratio of Fe to total thickness was found at a given thickness for the Co/Fe bilayer.