MICROMAGNETIC ANALYSIS OF MAGNETIZATION REVERSAL IN COPT ALLOY-FILMS

We have studied the magnetization reversal processes in polycrystallin e CoPt magneto-optic recording alloys with perpendicular magnetic anis otropy. Thin films of composition Co28Pt72 with total thicknesses in t he range 5 nm to 30 nm were investigated with Kerr contrast imaging. D epending on the film deposition parameters we find domain wall motion or domain nucleation dominated processes. Numerical simulations of the magnetization reversal processes were carried out within a two-dimens ional array model of interacting mesoscopic single domain particles. I ncluding dipolar fields and domain wall contributions, we find that th e demagnetizing fields dominate the reversal mechanisms and strongly a ffect the shape of the hysteresis loops. Additional microstructural an alysis reveals that the typical grain sizes of the (111) textured poly crystalline alloy films are of the order of about 20 nm which coincide s with the typical cell size representing a single domain particle in the micromagnetic numerical simulations.