R&D: Thermal Lagging of Multi-layered Structure in HAMR Systems

Journal of Thermal Science and Engineering Applications has published an article written by Jian Su, Tingting Tang, 1088 Xueyuan Boulevard Shenzhen, Guangdong 518055, China, Ruixin Lu, Queen Mary University of London, London, UK E1 4NS, United Kingdom, and Peng Yu, Department of Mechanics and Aerospace Engineering, Southern University of Science, Shenzhen, China 518055, China.

Abstract: “In the present study, we numerically investigate the thermal lagging behavior on the hard disk drives in heat-assisted magnetic recording systems via the optical absorption model. The influences of overcoats, laser radius, relative scanning velocities, interfacial thermal resistance, and the heat sink layer on the thermal lagging behavior are studied in detail. It is found that the thermal lagging distance, i.e., the horizontal distance between the location of the maximum temperature and the laser center, increases with an increment of speed and/or radius of the laser spot. The overcoats, the interfacial thermal resistance, and the heat sink layer have negligible effects on the lagging distance. Thus, the multi-layered disk can be simplified as a single layer disk for investigating thermal lagging distance. Meanwhile, the temperature gradient varies with these factors. Different overcoats result in different temperature gradient owing to the difference of in-plane thermal diffusivity. A laser with a smaller radius or a slower speed leads to a higher temperature gradient. The thermal resistance influences the temperature gradient insignificantly also. This study may provide useful information for the design of hard disk drives for heat-assisted magnetic recording technologies.“