Heat Assisted Magnetic Recording (HAMR)

The idea behind Heat Assisted Magnetic Recording (HAMR) is to improve the writability of the media by focusing heat energy to assist grain reversal. This approach appears viable for use with planar perpendicular media, albeit made from significantly different materials than the cobalt-based alloys used today: FePt and CoPt alloys have been identified as the leading candidates. The function of HAMR is basically to “trick” the head into magnetically switching a material by very rapidly heating the media directly in front of the head during the writing process. As the media cools, the head field is then strong enough to switch a small area of the media into an up or down orientation thereby creating a bit of stored information.

In a practical sense, one must integrate a laser and optical system (waveguide and aperture) into the magnetic recording head and engineer an efficient coupling of the laser energy into the media. Additionally, a whole new class of magnetic materials must be created or adjusted, and the media overcoat and lubrication materials must be engineered to withstand the heating and allow for effective coupling of the heat energy into the recording layer. During this recording process, thermal conduction must be controlled very precisely to balance heating and cooling the media.

The HAMR procedure is amenable to sputter deposition using existing media manufacturing tools, although some cathode modification and in-situ thermal annealing may be required; if thermal annealing is necessary then choice of media substrate may be limited to higher temperature materials such as glass and/or ceramic oxide materials. Neither of these would be major obstacles to manufacturing. The combined cost increase to produce heads and media for HAMR based recording systems should be less than $1.00 compared to current PMR technology. There should not be a significant capital equipment expense for disk production associated with this approach.

Intevac is involved with key customers in the development of HAMR-capable materials and the associated deposition tools. Our Lean 200 sputtering platform is fully capable of enabling the path to this new technology.