Effect of gradient alignment in heat assisted magnetic recording

• Published in: Journal of applied physics 2009-04, Vol.105 (7), p.07B905-07B905-3
• Main Authors: Gokemeijer, Nils J., Zhou, Hua, Karns, Darren, Batra, Sharat, Mallary, Mike, McDaniel, Terry, Seigler, M., Ju, Ganping, Peng, Y., Xiao, Min, Gage, Edward
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.3073948

Heat assisted magnetic recording (HAMR) is one of the leading technologies to extend magnetic storage. Significant progress has been achieved in head and media fabrication [ M. Seigler , IEEE Trans. Magn. 44 , 119 ( 2008 ) ; Y. Peng , TMRC, Seagate Research, 2008 ], resulting in a basic technology demonstration ( C. Hardie , ODS Conference Proceedings, 2008 ) of HAMR. Both field and field-gradient limitations of a conventional perpendicular recording are overcome by engineering the thermal profile (notably the gradient) and recording at a temperature near T c (thus requiring a smaller head field). We have used a micromagnetic recording model to study the effect of thermal and field-gradient alignment in HAMR by varying the separation between the thermal spot and the leading edge of the head field. The output of the recording model includes transition jitter, which is based on Monte Carlo simulations of isolated transitions. We use a realistic granular medium with H K ∼ 50 - 80   kOe and a grain size of ∼ 2.5 - 6   nm that covers a broad range of HAMR media parameters. The model indicates that HAMR can achieve > 1   Tbyte / in . 2 using a grain size of 6 nm and is scalable to > 4   Tbyte / in . 2 on a granular media by careful alignment of the thermal and magnetic field gradients.