Head-to-disk spacing control in contact recording studies

Recording studies with variable head-to-disk spacings have been carried out on a static test stand with a nanometer scale position accuracy. The head-to-disk spacing control was achieved through selective deposition of either supporting pads on the air bearing surface of commercial sliders or additional nonmagnetic layers (in this study, Cr) on commercial post-sputtering disks or the combination of these two. The additional supporting pads not only helped us solve the stiction problem but also allowed us to study the effect of head-to-disk spacing on the readout performance in a contact fashion. A series of read/write experiments have been carried out to study how the half-amplitude pulse width (PW ₅₀) parameter is dependent on the head-to-disk spacing by varying the height of the supporting pads or the thickness of the additional nonmagnetic layers or both using a commercial giant magnetoresistance head. It was found that some of the theoretical equations are able to predict the dependence of PW ₅₀ on the head-to-disk spacing, but some of them do not. The results may be useful for performing scaling analysis studies of future high- density recording systems.