MICROMAGNETIC MODELING OF MULTILAYER MEDIA

A micromagnetic model for the calculation of magnetization processes i n magnetic multilayer systems has been developed using a finite elemen t method. Shell elements which account for the multilayer structure an d a magnetic vector potential to treat long-range dipolar interactions are the essential features of the algorithm. Micromagnetic calculatio ns of hysteresis properties and domain structures in Co/Pt multilayer systems show a qualitative agreement with magnetic images obtained fro m field emission Lorentz microscopy. The nucleation field of Co/Pt mul tilayers increases with improving texture. Spatial fluctuations of the magneto-crystalline anisotropy energy create barriers for domain wall motion. The pinning field of domains increases with increasing grain size, The domain wall structure depends on he local magnetocrystalline anisotropy. The wall structure changes from a Bloch-type to a Neel-ty pe walt as the local anisotropy constant decreases. The quality of tex ture and the grain size significantly influence the jaggedness of doma ins in Co/Pt multilayers. Large grains and strong deviations of the ea sy directions from the film normal deteriorate the smoothness of domai ns and increase the transition width.