188th Special MMU Seminar


From Perpendicular Magnetic Recording to Heat Assisted Magnetic Recording

Dr. Kaizhong Gao
Seagate Technology
Date: August 26 (Mon), 2013
Time: 10:30 - 11:30
Place: 8th floor medium seminar room (Room 811,812), Sengen

Perpendicular magnetic recording (PMR) has been demonstrated to continue areal density growth beyond longitudinal magnetic recording (LMR). HAMR has been proposed for over two decades for 1Tb/in2 and beyond. Despite huge challenges in various aspects, steady progress has been made in HAMR. A 1Tb/in2 areal density demonstration was recently performed that exceeded PMR. In addition, a functioning HAMR drive was demonstrated. Here we will review these HAMR demonstrations. The initial demonstration clearly shows the impact of heating from NFT in the write process [1]. A more recent base technology spin-stand recording demonstration (BTD) of HAMR, at 1.007 Tbits/in2 resulted from advances in NFT heads and FePt media. We will also discuss major issues in HAMR, includes: media switching field distribution, alignment of the thermal and magnetic gradients, NFT protrusion, high sensitivity to head-to-media separation (HMS), and finally, the optical/thermal profile resolution limit. All of these are complex and highly interrelated.

[1] W. A. Challener et al., Nature Photonics, 3, 220(2009).