HAMR improves the writability of the media by focusing heat energy in order to assist grain reversal. This approach requires significantly different materials than the cobalt-based alloys used today, with FePt and CoPt alloys as the leading candidates. The primary function of HAMR is to “trick” the head into magnetically switching a material during the writing process by very rapidly heating the media directly in front of the head. 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, thus creating a bit of stored information.
- Improves writability by assisting grain reversal
- Magnetic materials used must now be able to withstand heating temperatures
- Intevac’s 200 Lean® platform is fully capable of enabling the path to HAMR-capable materials and associated deposition tools
The practical approach is to 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. A whole new class of magnetic materials must also be created or adjusted. 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 the 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.