Preconditioning, write width, and recording properties of Co-Cr-Pt-O perpendicular media with various underlayer designs

The effect of magnetic "preconditioning" on the recording performance of perpendicular media is investigated. Furthermore, the dependence of the magnetic write width (MWW) of shielded-pole heads (SPH) on soft-underlayer (SUL) type and thickness (t_SUL) and the recording performance of perpendicular media with thin SULs are examined. The MWW dependence on SUL structure is influenced by the pole-to-trailing shield spacing. For a wide-gap (∼80 nm) SPH, thick single-layer, SULs are preferred. For a narrow-gap (∼50 nm) SPH, MWW is less sensitive to the SUL type. For both narrow and wide-gap SPH and for media with an antiferromagnetically-coupled SUL, MWW is reduced for t_SUL<100 nm. Comparable performance is achieved relative to media with t_SUL∼150 nm.