Write Protrusion Modulation for Sub-Nanometer Contact Interference

Abstract

With the continual reduction in slider to disk clearance in hard disk drives, new methods to measure this clearance with high accuracy are needed. Understanding the contact dynamics when touching the disk at sub-nanometer interference levels is an important aspect of the problem. We have developed a new methodology to gradually bring the slider into contact with the disk, based on controlled and localized thermal expansion of the slider as it occurs during the regular write process (write induced protrusion). By applying short pulses to produce time controlled thermal protrusion, the duration of contact can be limited to a few milliseconds, by which short contacts and their contact hysteresis can be investigated.