Magnetostatic and recording analysis of RF-sputtered double layer media for perpendicular recording

The paper describes the preparation, characterization and properties of RF-sputtered double-layer (DL) media for perpendicular magnetic recording. The media, consisting of CoCr on top of a soft magnetic NiFe layer, are deposited on Si wafers or polyester (PET) foils. The influence of an intermediate layer on the magnetic properties such as the NiFe coercivity, is described in terms of magnetostatic (de)coupling. In-contact recording experiments using ring heads include signal as well as noise measurements. Spike noise is observed in low-Hc(NiFe) DL media, which probably may be ascribed to domain-wall displacements in the underlayer. The relation between the noise output and Hc(NiFe) is shown.