Flying characteristics at ultra-low fly height in presence of van der Waals force: a comparative study

In this paper, the flying characteristics of several air bearing designs, e.g., Seagate, INSIC, DSI, have been studied at ultra low fly heights with a Seagate air bearing program. The results showed the significant effect of vdW force on air bearing static fly height, touch down and take-off velocities, especially at ultra-low fly heights. It clearly demonstrated the necessity of performing the full Lifshitz calculation on a realistic layered model of HDI for accurate van der Waals force (vdW force) calculation. The magnitude of the vdW force and its distribution on these air bearing surfaces are described in detail and are highly air bearing geometry dependent. Its relevance to the reliability of the head-disk interface at ultra-low fly height is discussed.