Effects of head wear performance with respect to the lubricant thickness on hard disk media for ultra-thin lubricants

Magnetic head wear performance was studied using various thicknesses of D-4OH lubricant that covers hard disk media. The characteristic head wear behavior to over-push the dynamic flying height power differed for each lubricant thickness. The difference in the behavior was highly dependent on the media friction coefficient. The surface free energy also varied as a function of the lubricant thickness. According to the lubricant coverage analysis, we found that the head wear behavior and the friction were dependent on the lubricant coverage change as a function of the lubricant thickness. Furthermore, the molecular dynamics method was applied to investigate the lubricant molecular distribution; the coverage changed with the lubricant thickness similar to that in the experiment. Finally, a head-disk interface mechanism under an over-pushed state was discussed, and meniscus bridge formation was suggested to have occurred at touchdown power for each lubricant thickness.