Analysis of Heat-Assisted Magnetic Recording to Density of 4 Tb/in $^{\textbf {2}}$

Thermal performance of media is a key factor limiting heat-assisted magnetic recording density. In this paper, the effects of near-field optical transducer tip size on the thermal profiles of media are studied, and the results show that even with a tip size of 10 nm, the obtained cross-track thermal spot size and down-track thermal gradient still cannot meet the requirements of 4 Tb/in $^{2}$ for continuous-wave laser heating. Pulse laser heating can improve the thermal distribution significantly, and the requirements for 4 Tb/in $^{2}$ can be met at a pulsewidth of 100 ps. Dynamic micromagnetic recording simulation with Landau–Lifshitz–Bloch equation is conducted for pulse laser heating recording. The results indicate that 4 Tb/in $^{2}$ density is realizable for FePt recording media. It is also pointed out that, for short-pulse laser heating recording, media with large magnetic damping constant is important.