R&D: Impact of Radius and Skew Angle on Areal Density in HAMR HDD

AIP Advances as published an article written by Michael Cordle, Storage Research Group, Seagate Technology, Shakopee, MN 55379, USA, and Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA, Chris Rea, Recording Head Operations, Seagate Technology, Bloomington, MN 55435, USA, Jason Jury, Tim Rausch, Cal Hardie, Edward Gage, Storage Research Group, Seagate Technology, Shakopee, MN 55379, USA,and R. H. Victora, Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA.

Scan line images of magnetization footprint (a)
and their corresponding transition curvature profiles (b)
measured at zero skew and at +/- 14° skew angles in a HAMR HDD.

Click to enlarge

Abstract: “This study aims to investigate the impact that factors such as skew, radius, and transition curvature have on areal density capability in heat-assisted magnetic recording hard disk drives. We explore a ‘ballistic seek’ approach for capturing in-situ scan line images of the magnetization footprint on the recording media, and extract parametric results of recording characteristics such as transition curvature. We take full advantage of the significantly improved cycle time to apply a statistical treatment to relatively large samples of experimental curvature data to evaluate measurement capability. Quantitative analysis of factors that impact transition curvature reveals an asymmetry in the curvature profile that is strongly correlated to skew angle. Another less obvious skew-related effect is an overall decrease in curvature as skew angle increases. Using conventional perpendicular magnetic recording as the reference case, we characterize areal density capability as a function of recording position.“