Study of Lubricant Depletion Induced by Pulsed-Laser Irradiation Heating in Heat-Assisted Magnetic Recording

In this study, we experimentally investigated the lubricant depletion caused by pulsed-laser irradiation heating and discussed the fundamental characteristics, comparing it with the results obtained by continuous laser heating. As a result, it was found that the decrease in the lubricant depletion due to pulsed-laser heating was smaller than that to continuous laser heating and depended on an increase in the duty ratio as it increased. In addition, the lubricant depletion depends on the full width at half maximum (FWHM) of the temperature distribution due to pulsed-laser irradiation heating and increased as the FWHM increased. Therefore, it is also suggested that the lubricant depletion issue will not be so critical in actual HAMR systems because the FWHM would be very small.