Improvement of perpendicular magnetic properties by postannealing for M'-CoCrPt-M stacked media (M, M'=Ti, Ta, Ru, Pt, CrMn, MnSi)

In this paper, we discuss the effect of postannealing on magnetic properties and microstructure for CoCr-based perpendicular recording media. Material investigation for cap- and under-layers of the postannealed media is carried out, and significant improvement of magnetic properties is confirmed for the media with both titanium cap- and under-layers. This is caused by decoupling of magnetic exchange interaction among grains due to diffusion of Ti into the grain boundaries and by elimination of the nanocrystalline initial layer that behaves like a soft magnetic layer.