Head-disk interface considerations at 10-nm flying height

As magnetic recording density increases toward hundreds of Gb/in², both the magnetic spacing and head-disk clearance decrease to <10 nm. By one estimate, the magnetic spacing for 1 Tb/in² is about 6 nm and the read width is ∼30 nm. There are at least two different approaches to achieving this. The first is an extension of the traditional flying interface and the second is contact recording. In the former case, one needs to be concerned about maintaining adequate clearance both at sea level and at higher elevation, whereas in the latter case wear and corrosion of the heads and disks may pose major challenges. An example of how head-disk interference takes place in a disk drive is given for an experimental 10-nm flying slider. The effects of radial flying height profile, takeoff height of the disk, and disk curvature on mechanical spacing are presented. The results of changes occurring on the air bearing surface and the disks after long-term flyability tests are discussed.