Theoretical investigation of magnetization configuration and reversal processes in exchange-coupled multilayers

An analytic study of magnetization profiles and reversal processes is performed in exchange-coupled double and trilayers (ECDL and ECTL) corresponding to mixed parallel and perpendicular anisotropy structures (M/sub 1//M/sub 2/) and (M/sub 2//M/sub 1//M/sub 2/) where M/sub 1/ corresponds to planar magnetization layers NdCo or GdFeCo and M/sub 2/ are perpendicular magnetization layers TbFeCo or DyFeCo. The changes of the profiles with magnetic parameters of the layers are calculated from a variational method of the magnetic energies in a continuum model in ECDL and from a noncontinuum model method in ECTL. The effective exchange field induced at the interface by the capping layer M/sub 1/ for thickness higher than a critical value is calculated and its influence on the reversal process of the "perpendicular" layer M/sub 2/ is determined in ECDL. Both the continuous and noncontinuous models are useful to optimize magnetooptical structures and the results from these models are compared.