Induced slider vibration over various LZT media at small disk-slider clearance - A challenge to 0.5 mu inch glide testing

Both frequency- and time-domain analyses of glide signals from a PZT glide- slider flying over a laser zone-textured (LZT) thin film disk medium were u sed to determine the slider vibration at a small disk-slider clearance. Sli der vibration was found to be particularly dependent on the uniformly place d laser bump and the effects due to the air-bearing stiffness over the LZT medium, We found that a high density of small, pointed laser bumps (10X) ha s a more distinct impact on airflow than large, jagged-rim craterlike laser bumps (1X) on the slider. We therefore investigated the effect of laser bu mp density on the slider vibration, and found that marginally higher laser bump density (3X versus 2X) results in higher slider vibration. While reson ant vibration has been a major glide problem, the effects of laser bump den sity have also recently become important in the face of ultralow glide heig ht, 0.5 mu " (12 nm). Its influence can be clearly observed when the disk-s lider clearance becomes very small. At such an ultrasmall disk-slider clear ance, even minimal slider vibration can be detrimental to the head-disk int erface. Taking into account the various contributions of slider vibration a nd considering possible damage to the head-disk interface, it is clear that the optimization of laser bump design should go beyond just the glide heig ht and coefficient of stiction. It should take into account the effects of laser bump height, density and spatial distribution on vibration-induced fl ying height variation while maintaining a low glide height and coefficient of stiction. An ideal LZT medium should therefore have low bump height to e nable low glide height, i.e., 0.5 mu " (12 nm), but specific bump shapes an d sufficient density to achieve low stiction. Laser bump density should, ho wever, be controlled to moderate its effect on slider vibration and possibl y disk-slider collision (297 words).