Dependence of optical laser power on disk radius, head-disk spacing and media properties in heat-assisted magnetic recording

In heat-assisted magnetic recording, minimization of optical laser power is important for the reliability of the head-disk interface. In this paper, a prototype heat-assisted magnetic recording system is used to investigate the relationship between the needed optical laser power and disk drive design parameters. In particular, the change of optical laser power, which is a function of the laser current, is investigated for different disk radii and write head flying heights while keeping the write width of the recorded signal constant. In addition, the dependence of laser power during writing is studied as a function of the thickness and material properties of a very thin “capping layer” on the top of the recording magnetic layer. The results show that laser power and media design parameters play a crucial role in heat-assisted magnetic recording devices.