Analytical Investigation of Touchdown Characteristics of Flying Head Slider for Quasi-Contact Recording

Reducing the fly-height between the head and disk to less than 1 nm with high reliability is necessary to improve the recording density of magnetic disks. Therefore, the mechanism of the head touchdown (TD) phenomenon, particularly the surfing state after the TD, needs to be understood. Assuming that the contact sliding on the sub-nanometer asperities, covered with a monolayer lubricant film, generates the lubrication film forces and reduces the surface forces, the present study shows that numerical simulations of a one-degree-of-freedom slider model can be used to understand various TD phenomena, including surfing conditions. The three different TD behaviors of a commercial head slider were explained by the differences in the rate of generation of the lubrication film force after the TD and initial surface force. The parametric studies demonstrated that surfing states could be generated at a separation of more than three times the standard deviation of the asperity height by increasing the surface force and magnitude of the disk-waviness, thereby suggesting the possibility of quasi-contact recording.