Analysis of Microwaviness-Excited Vibrations of a Flying Head Slider in Asperity Contact Regime

Abstract

The flying height of a head slider in hard disk drives has been decreased close to 1 nm but still must be reduced to ∼0.5 nm in order to increase recording density. At such a narrow spacing, variation in head/disk spacing caused by microwaviness (MW) becomes a significant concern [1]. Some comprehensive numerical simulations of slider dynamics in the near-contact and contact regimes have been conducted [2–5]. However, the real physics behind slider dynamics does not seem to be fully elucidated because the head-disk interfacial force changes with differences in interfacial design conditions such as the air-bearing surface, surface roughness, and lubricant layer. In this study, we evaluated head-disk interfacial forces by asperity adhesive contact theories with measured asperity parameter values. The MW-excited vibrations of a thermal fly-height control (TFC) slider in proximity and asperity contact regimes were simulated by changing the design parameters. It was found that the simulated results allow us to understand typical experimental results reported in previous literature.