Pole-tip protrusion effect on head-disk interface at low flying clearance

As the head-disk flying clearance is reduced below 10 nm or less, write-current-induced pole-tip protrusion (PTP) plays a significant role in tribology performance at the head-disk interface. PTP effect on the head-disk interaction at close proximity flying is studied through a new approach utilizing controlled PTP with acoustic emission sensing. Actual flying clearance can be measured and controlled through this technique. The PTP contact hysteresis phenomenon is investigated and used to characterize the lubricant properties at head-disk interface. The dependence of lubricant thickness and bonded lubricant ratio to contact hysteresis is reported. Different features of head pickup and lube redistribution due to PTP effect are discussed.