Perpendicular drive integration

This paper reports on progress in perpendicular drive integration. In the first part, the performance of a series of perpendicular media with different coercivity (5-6 kOe), nucleation field, and soft-underlayer thickness (120/80 nm) is compared using two different head designs. Good overwrite and bit error rate performance is achieved for all head/media combinations. Higher coercivity leads to lower linear density but higher track density, resulting in approximately equal areal density capability. The thinner soft underlayer causes wider erase bands and therefore a loss of areal density. Wide-area track erasure measurements were performed on all media. The media with lower coercivity do not show any measurable amplitude loss, due to their larger absolute value of the nucleation field and the smaller write current needed to write on them. Two types of single-head, 7200 RPM desktop perpendicular drives (40 and 80 GB capacity) were built using 95 mm perpendicular media. They both achieve good bit error rate and off-track capability in all zones. The thermal decay for the 40 GB drive was measured and compared to a similar longitudinal drive. It was found that the thermal decay rate is much smaller in the case of the perpendicular drive in the range -6°C to +80°C.