Thermal Diffusion Phenomena of the Functional Polymer Lubricants for the Heat-Assisted Magnetic Recording

Abstract

Materials in a newly designed head–disk interface in the heat-assisted magnetic recording (HAMR) have to satisfy harsh operating conditions including cyclic thermal stresses generating large thermal gradient where the heated lubricants evaporate as well as thermally flow-out. Therefore, the stumbling block in the HAMR technology is to fully understand the system behavior under large thermal effects on the lubricant diffusion related to the depletion in the heated zone. The previous studies have investigated local thermal diffusion, depletion, and recovery phenomena of nonfunctional perfluoropolyether lubricant by studying the lubricant behavior at the center and the formation of a rim at the edge of heated zone, while the diffusion mechanism in the heated area has not been fully understood. In this paper, we examined the thermal effects on the lubricants for the application of HAMR in two aspects: 1) thermal diffusion for the replenishment and 2) lubricant evaporation for the loss of the lubricant by using the molecular dynamics.