Lubrication effects on head–disk spacing loss

As flying heights are reduced to 10 nm or less, maintaining good flyability becomes critical to ensuring the robustness of the head–disk interface. One way to reduce the head–disk interference during low flying is to minimize the media portion of the head–disk spacing loss. In this work, both Touchdown RPM and Pump down Pressure tests were used to measure this parameter. Experimental results from this study show that the free lubricant thickness is a major contributor to the loss and results in the observed hysteresis between the Touchdown and Take off Pressures (or RPM).