R&D: Rotated Read Head Design for High-Density Heat-Assisted Shingled Magnetic Recording

Applied Physics Letters has published an article written by Wei-Heng Hsu, and R. H. Victora, Center for Micromagnetics and Information Technologies, University of Minnesota, Minneapolis, Minnesota 55455, USA, and Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.

Abstract: “In heat-assisted shingled magnetic recording, recorded tracks are erased on one side. The transitions are no longer symmetric relative to the track center, especially when the transitions are highly curved as a result of the temperature profile generated by the near-field transducer. To optimally utilize these asymmetrically curved transitions, the read head is rotated to match the curvature. For a single rotated head, a more than 10% improvement in user density is achieved compared to that of a single non-rotated head. We found that the optimal rotation angle generally follows the transition shape. With an array of two rotated heads, a track pitch of 15 nm, and a minimum bit length of 6.0 nm, the user areal density reaches 6.2 Tb/in², more than 30% above previous projections for recording on granular media.New data are created and stored every second; the total global data storage may exceed 175 zettabytes by 2025.To accommodate this stored data growth, hard disk drives remain solid candidates for data centers because they are less costly than solid-state drives. Heat-assisted magnetic recording (HAMR) has been introduced as the successor to contemporary perpendicular magnetic recording to extend areal density growth.“