Impact of Curie Temperature Distribution and Anisotropy Field Distribution on the User Density of HAMR Under Different Thermal Gradients

We report the effects of Curie temperature (Tc) distribution (σTc ) and anisotropy field (Hk) distribution (σHk ) on the user density (UD) of heat-assisted magnetic recording (HAMR) under two distinct thermal gradients (10 and 26 °K/nm) using micromagnetic simulation. We also estimate the transition jitter analytically and compare with our simulated results. According to our findings, UD is more sensitive to σTc variance than σHk variance in both high and low grain pitch media. This is because a variation in the media Tc substantially increases the transition jitter noise in the recording. We also demonstrate that anisotropy field variation has increased effect at lower densities, as a consequence of grain-size-limited transition jitter and number of grains per bit. Furthermore, we found that Tc and Hk variations have a similar impact on UD at greater magnetic fly heights (FHs), although the sensitivity level is lower.