Direct measurement of disk-to-head back-heating in HAMR using a non-flying test stage

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.