Recording and transition noise simulations in thin film media

Micromagnetic simulations of the recording of a single transition in thin-film metallic media are presented. The film is modeled as a planar array of hexagonal single-domain particles with long-range magnetostatic as well as possible nearest-neighbor exchange interactions. Magnetization configurations are determined by following the Landau-Lifshitz equations of motion with finite damping. The media parameters used here approximate Co films. The recording geometry resembles a close flying head with a small gap. Transition fluctuations, a source of transition noise, are also suited for both non-exchange-coupled and exchange-coupled media. It is shown that intergranular exchange coupling can significantly enhance transition noise and that films with well defined nonmagnetic grain boundaries exhibit better signal-to-noise ratios. >