Duty Cycle Effects in Z-Tetraol Reflow in Heat-Assisted Magnetic Recording

Abstract

Lubricant reflow for 10 Å Z-Tetraol film is characterized for heat-assisted magnetic recording by numerical simulation using the experimentally determined thickness-dependent diffusion equation. The competition between laser-induced lubricant depletion (troughs) and subsequent healing by reflow is investigated as a function of lubricant depletion rate, trough width, trough depth, and duty cycle (reflow time between successive laser exposures). The simulations include 1, 5, 9 and 13 adjacent troughs. Trough width of 50 nm with an edge-to-edge separation distance of 50 nm and laser depletion rates of 1.0, 0.1 and 0.001 Å/cycle are simulated. Reflow kinetics on 13 troughs with a trough width of 20 nm and an edge-to-edge separation distance of 20 nm is also included to probe the effects in the limit of very small laser spots. Duty cycles of 10 and 100 millisec are used in the simulations. The results of the numerical simulations indicate that trough recovery by reflow increases with increasing duty cycle or decreasing number of adjacent troughs, trough separation distance and laser depletion rate. Conclusions based upon single trough studies are misleading for HAMR interfaces.

Keywords

• z-tetraol
• hard disk drives
• heat-assisted magnetic recording
• reflow
• diffusion