MICROMAGNETICS OF SOFT-MAGNETIC THIN-FILMS IN PRESENCE OF DEFECTS

We solve numerically the Landau-Lifshitz-Gilbert equation and calculat e the magnetization in a magnetic film including a nonmagnetic defect for two initial magnetization slates consisting of circular structure with 4 domains and 7 domains. The defect at the vortex wall restrains the magnetization temporarily but the vortex wall comes out of the def ect beyond a critical applied field. This critical field increases as the defect size becomes large. The defect at the film side fixes the m agnetization at the film edge. The edge defect leads to a reproducible magnetization state inside the film, though a locally stable structur e appears for the magnetic thin film without defects. It seems that th e defect may improve the stability of the magnetic thin film head. (C) 1995 American Institute of Physics.