SOME ADVANCED AIR-BEARING DESIGN ISSUES FOR PROXIMITY RECORDING

In magnetic hard disk drives the minimum spacing between the air-beari ng slider and disk has been reduced to under 50 nm, and some drives no w employ so-called proximity sliders that are designed to operate at s ome level of interference between the slider and the peak asperities o n the disk. This ultra-low flying condition brings into play some new interface phenomena and accentuates some of the well known ones as wel l. In this paper, we consider some air-bearing design issues related t o proximity recording. First, we examine the effects of shear flow in the bearing, which is usually neglected, and we show that for high-pit ch proximity slider designs the effect is not negligible. Next, we not e that such low spacing also tends to accelerate particle accumulation at the trailing edges of the slider. In art effort to address this pr oblem, a model is developed for calculating forces on particles in the air bearing. Including this in the CML air bearing design code we sho w that designs can be created that eject most of the particles from th e sides rather than trapping them at the trailing edge. Finally, we in vestigate the performance of proximity sliders with regard to their se nsitivity to altitude changes. We include altitude sensitivity as an o bjective in the design optimization scheme and demonstrate that it can yield air-bearing design with performance much less sensitive to chan ges in altitude.