Experimental Study of Lubricant Depletion in Heat Assisted Magnetic Recording

• Published in: IEEE transactions on magnetics Vol. 48; no. 5; pp. 1813 - 1818
• Main Authors: Ma, Y. S., Chen, X. Y., Zhao, J. M., Yu, S. K., Liu, B., Seet, H. L., Ng, K. K., Hu, J. F., Shi, J. Z.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.05.2012; Institute of Electrical and Electronics Engineers
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Hard disk drive; Heat-assisted magnetic recording; Heating; Laser beams; laser irradiation; lubricant depletion; Lubricants; Materials science; Other topics in materials science; Physics; Power lasers; Surface emitting lasers; Hard discs; Disc drives; lubricant depletion; Lubricants; Hard disk drive; Laser irradiation; Experimental study; heat assisted magnetic recording; Magnetic recording; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2011.2170962

Heat assisted magnetic recording (HAMR) is a promising choice to overcome the superparamagnetic limit in magnetic recording and further increase the areal recoding density of a hard disk drive. However, HAMR brings about serious lubricant depletion problems on the disk surface due to the high temperature in the heat assisted writing process. Experimental studies of the lubricant depletion under HAMR conditions are still very limited so far. It is essential to do experimental studies under real HAMR conditions or under equivalent conditions if a stand-alone laser is used to emulate the HAMR system. In this work, a self-developed HAMR tester is introduced. A method to control the repeatability of laser heating temperature is explained. Lubricant depletion, accumulation, loss, the percentage of accumulation to depletion, and the depth of depletion are determined quantitatively. The effects of laser power, total laser-on-time and laser-off-time in one laser heating and cooling cycle on lubricant depletion are studied experimentally with the HAMR tester. From the experimental studies, it is found that lubricant accumulation at the edge of the lubricant depletion track takes a considerable percentage of the lubricant depletion and the lower the laser heating temperature, the higher the percentage is. Furthermore, media cooling time plays a significant role in lubricant depletion for the media without a heat sink layer and on glass substrate.