R&D: Direct Measurement of Disk-to-Head Back-Heating in HAMR Using Non-Flying Test Stage

Applied Physics Letters has published an article written by Qilong Chenga, Siddhesh V. Sakhalkar, and David B. Bogy, University of California at Berkeley, Berkeley, California 94720, USA.

Abstract: “Heat assisted magnetic recording, as one of the next generation hard disk drive solutions to high areal density over 1 Tb/in.2, integrates a laser delivery system to facilitate data writing. A laser beam is launched from the recording head and is focused on the recording disk to locally heat the disk (400–500 °C), which is even hotter than the head temperature (150–250 °C). Therefore, understanding the thermal transport between the head and the disk is of great importance. In this paper, we used a non-flying test stage to exclude the strong air cooling caused by the rotating disk and performed the thermal transport experiments across a closing nanoscale air gap on two substrates (silicon wafer and AlMg-substrate disk). The experimental results show that the disk-to-head back-heating from the hot spot on the substrate can be directly measured in the case of the AlMg disk (?2–10 °C), while the silicon case shows no back-heating due to its high thermal conductivity. It is demonstrated that the experimental setup is useful for thermal transport studies between two macroscopic surfaces and future development of such microelectronic devices.“

The work was supported by the Computer Mechanics Laboratory (CML) at University of California, Berkeley, and funded by Advanced Storage Research Consortium (ASRC). We thank Robert Smith, Erhard Schreck, Qing Dai, Sukumar Rajauria, and Tan Trinh of Western Digital and Huan Tang of Seagate for supplying the components and providing insightful discussions.