Experimental study of media heat sink thickness impact on signal-to-noise ratio in heat-assisted magnetic recording

Abstract

Recently, heat-assisted magnetic recording (HAMR) has been demonstrated to extend the areal density growth over the superparamagnetic limited. One key component of this technology is a heat sink layer in HAMR media, which benefits the thermal gradient and transition noise. However, the disadvantage of the heat sink layer (HS) has not been fully explored. In this paper, we investigate the background interference (BGI) impact as a result of the heat sink layer via the spin-stand tester. HAMR heads included a light delivery system that have measured a signal-to-noise ratio and down-track thermal gradient on a variety of HS thickness. Subsequently, we found that a thicker HS is a trade-off between the BGI and thermal gradient. Thus, it remains challenging to achieve an ultra-high areal density using the thermal media design.