Minimum Stable Flying Height with Thermal Protrusion Actuation

With ever increasing areal densities in magnetic recording, novel methods to accurately control the clearance between slider and disk are needed. One recently introduced method is thermal protrusion of a heater element located close the read/write element at the trailing end of a slider. By applying an electric current to the heater coil, the slider´s trailing end protrudes towards the disk and can be driven into contact with sufficiently high heating power. Understanding the contact dynamics and the touch-down/take-off hysteresis is an important aspect of controlling the minimum stable distance between the slider and disk. In this paper, a novel method to measure touchdown and take-off hysteresis with a single pulse applied to the heater is introduced. Furthermore, the effect of air bearing compliance as a function of thermal protrusion is investigated. By modifying the pressure profile of the air bearing surface, improved actuation efficiency can be achieved