4–5 Tb/in Heat-Assisted Magnetic Recording by Short-Pulse Laser Heating

Due to poor thermal performance of media, it is difficult for heat-assisted magnetic recording (HAMR) to achieve densities greater than 3 Tb/in² for continuous-wave laser heating. Short-pulse laser heating is an attractive approach to improve the thermal response of media. In this paper, the recording performances of HAMR using short-pulse laser heating are studied by dynamic micromagnetic simulations solving the Landau-Lifshitz-Bloch equation. The results show that the magnetic damping constant of the media, α, and applied magnetic field, H, exhibit significant effects on recording quality at a pulse-width of 100 ps. From analyses of the relationships among readout signal and noise ratio, recorded track width, α, and H, the required parameter setting for various recording densities are obtained. It is indicated that with a transducer tip size of 15 nm and heating laser pulse-width of 100 ps, a recording density greater than 4 Tb/in² is achievable for FePt recording media.