R&D: Heat-Assisted Magnetic Recording for 3TB/platter

IEEE Transactions on Magnetics has published an article written by Bogdan Valcu; Tobias Maletzky; Moris Dovek; Headway Technologies, Milpitas, California, USA, Xiao Ming Liu; and Anthony Lai, SAE Magnetics, Hong Kong, China.

Abstract: “In this work we present recording data taken on a spin-stand using Heat- Assisted Magnetic Recording (HAMR) components. In HAMR, the laser current (applied to assist writing onto the media) determines the track width. First, we show how to optimize the laser current for a given track density. Maximum ADC is obtained through a 3-level nested loop algorithm: KTPI (Track Density)-> Laser Current-> KFCI (Linear Density). Max ADC is then simply calculated as the product of KTPI x KFCI. Subsequently, we show how ADC depends on basic recording metrics: down-track Thermal Gradient (TG), WCAP (metric for the magnetic field strength), and reader metrics (head SNR, reader width and reader asymmetry). Salient recording physics features include linear density capability saturation with TG, and WCAP decrease with the distance from the magnetic pole to the NFT. For a large number of Headway heads of the same design, a median value of ADC ~ 1,800 Gb/inch ² was achieved. This is equivalent to 3.1 TB/platter (HDD capacity).“