Case study of media noise mechanisms in longitudinal recording

A comprehensive study (TEM, MFM, AFM, XRD, Recording Performance and Magnetometry) of media noise mechanisms and their relation to grain structure is reported for model, high noise contrast, CoCrPtTa thin films. The CoCrPtTa media were sputtered on to either CrMn or NiAl/CrMn underlayers causing a change in media noise power of 9 dB. The changes in media noise are not related to the topography of the underlayer(s) or due to interaction effects, which the delta M technique suggests are negligible in these model samples. A quantitative correlation is obtained between magnetic cluster size and media noise using an analytical first approximation of Zhou and Bertram's micromagnetic model.