気体軸受圧力による磁気ディスク媒体及びスライダの表面変形

Abstract

The slider/disk spacing of magnetic disk drives has been reduced in order to increase the recording density. Especially, the thermal flying-height control technology, where the electromagnetic transducer is protruded into the slider/disk spacing by heating the slider partially, contributes to make the flying height less than 2nm. Because of the narrower gas bearing clearance, the bearing pressure rises up to several tens times of atmospheric pressure. This pressure rise causes the deformation of slider and disk surface. The slider and disk surface deformation causes the change of gas bearing clearance and consequently the change of air bearing pressure. The pressure change causes the flying attitude. The flying characteristics also may be different from that of expected at the design, where the effect of deformation is not included. It is important to estimate correct flying characteristics affected by the deformation to realize stable flying and accurate recording. We introduced iterative method for searching the flying attitude affected by the slider/disk deformation. We obtained the air bearing pressure by solving the molecular gas lubrication equation numerically. And the simple numerical method, which utilizes the elastic half-space assumption, was employed for calculating the deformation of pressurized disk surface. The finite element method was applied to analyze the slider deformation. And the effect of deformation on the slider attitude is evaluated.