Head and Granular Media for Thermally Assisted Magnetic Recording for Recording Density of 6 Tb/in $^{2}$

Optimum structural dimensions and characteristics of a granular thermally-assisted-magnetic-recording (TAMR) medium for a recording density of more than 6 Tb/in² were investigated by using optical, thermal, and Landau-Lifshitz-Gilbert (LLG) simulators. A sharp thermal profile in the medium could be obtained by using a heat-sink layer with heat conductivity greater than 100 W/m K. The ratio of in-plane κ to out-of-plane κ(κ_xy/κ_g) of the recording layer and thickness (Tm_MgO) of the MgO layer should both be decreased. The targets for magnetic-write width (MWW) and signal-to-noise ratio (SNR) are 18 nm and 12 dB for a recording density greater than 6 Tb/in², respectively. In the case of Tm_MgO of 12 nm, the conditions for achieving these targets are ΔT of 450 K and H_eff of 1.36 MA/m. In the case of Tm_MgO of 5 nm, the conditions are ΔT of 600 K and H_eff of 1.4 MA/m (namely, MWW of 18 nm and recording density of 6.0 Tb/in²); ΔT of 550 K and H_eff of 1.48 MA/m (namely, MWW of 16.5 nm and recording density of 6.5 Tb/in²); and ΔT of 500 K and H_eff of 1.58 MA/m (namely, MWW of 15.0 nm and recording density of 7.2 Tb/in²). It is also clear that the thermal profile is a determinant factor in MWW.