Fly-Ability and Durability Test of Dynamic Fly Height Heads at 1 nm Clearance

Abstract

Thermal protrusion of the heating element built in the DFH slider can be used to control the head-to-media spacing (HMS) by applying controllable electrical power. It is very convenient to obtain ultra-low flying height (FH) and make slight contact with the disk using such a slider. In this study, we achieved 1 nm clearance flying over the disk using the DFH slider by making the protrusion back off 1 nm immediately after touchdown (TD). Moreover, the fly-ability of the DFH slider flying at 1 nm clearance was investigated by monitoring laser Doppler vibrometer (LDV), acoustic emission (AE) and friction signals. In particular, the durability of the HDI at such small spacing was evaluated by inspecting the wear level of the sliders and the disks after different durations of fly using scanning electron microscopy (SEM) and Candela optical surface analyzer (OSA) respectively. Finally, the possibility of stable flying of DFH slider at sub-nanometer clearance was demonstrated experimentally.