Experimental Study of Head-Disk Interface Instability on Light Contact Recording Using Dynamic Flying Height Control

The instability of the slider touchdown process was observed by the sensitive method that uses PZT ((Zr_x Ti_{1 - x}) O₃ ) sensor mounted on a suspension. By using this method, we could differentiate from the contact between the slider and the lubricant surface, the stable regime beyond touchdown (surfing regime), and the final full contact with the disk surface. Z-dol2000S clearly showed the surfing regime, but Z-tetraol2000S did not show the surfing regime on a thin lubricant film with a thickness of less than 16 Å. In the case of Z-dol, the magnitude of the slider vibration at the contact on the lubricant surface depended on the lubricant thickness; in the case of Z-tetraol, a large vibration was observed only at 20 Å. We have tried to explain these phenomena with the help of potential energy curves that are based on intermolecular forces calculated by molecular dynamic simulations. Potential energy curves could be used to explain the stability of the touchdown process.