Noise characteristics of double-layered perpendicular media using Fe-Ta-C underlayer

The noise characteristics of double-layered perpendicular media having an F e-Ta-C soft-magnetic underlayer were investigated. It was revealed that cha nges in soft magnetic properties and a consequent increase in media noise o ccurs when C or Ta are reduced from the standard composition. Two-dimension al spike distributions were observed in a medium using the standard Fe-Ta-C composition, possibly caused by temperature inhomogeneity during the annea ling process. It was also concluded that the noise contribution of the spik es was minimal for disks using an Fe-Ta-C SMU.