In the developing heat-assisted magnetic recording (HAMR) technology, a laser heats up the magnetic media to the Curie temperature of a few hundred degrees Celsius for a short time of the order of a few nanoseconds. Accordingly, the thin-film lubricant coating on the disk experiences effects such as thermo-capillary shear stress, evaporation, viscosity drop, and eventually, lubricant depletion [1, 2]. Our previous work [3] studied these effects on the lubricant depletion for various lubricants and a prescribed Gaussian temperature distribution with a peak temperature of 350°C and a Full-Width Half Maximum (FWHM) of Ls = 20nm, close to the target laser spot size for HAMR. In order to maintain a reliable head-disk interaction, the lubricant needs to recover to the initial uniform profile. A previous work by Dahl and Bogy [4] studied the recovery process after HAMR writing for Z-dol 2000 using lubrication theory. In this paper, we focus on the effect of the lubricant functional end-groups on the recovery process, using the same method. Z-dol, Z-tetraol, and ZTMD lubricant families have the same polymer backbone but different numbers of hydroxyl end-groups [5]. This difference modifies two key parameters, both affecting the recovery time significantly. First, it changes the bonding ratio and the disjoining pressure properties of the lubricant. Figure 1 shows the disjoining pressure derivative, including both the polar and dispersive components, as a function of film thickness for Z-dol2000, Z-tetraol2200, and ZTMD2200 based on experiments [1, 6, 7]. Second, a major increase in lubricant viscosity occurs as the number of hydroxyl end-groups increases from two (Z-dol) to four (Z-tetraol) to eight (ZTMD) [3]. Fig. 2 shows the viscosity μ(h) as a function of the local lubricant thickness for all three different families of lubricants at the room temperature.
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ASME 2016 Conference on Information Storage and Processing Systems
June 20–21, 2016
Santa Clara, California, USA
Conference Sponsors:
- Information Storage and Processing Systems Division
ISBN:
978-0-7918-4988-0
PROCEEDINGS PAPER
Effect of Functional End-Groups on the Lubricant Recovery After Heat-Assisted Magnetic Recording (HAMR) Writing
Soroush Sarabi,
Soroush Sarabi
University of California, Berkeley, Berkeley, CA
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David B. Bogy
David B. Bogy
University of California, Berkeley, Berkeley, CA
Search for other works by this author on:
Soroush Sarabi
University of California, Berkeley, Berkeley, CA
David B. Bogy
University of California, Berkeley, Berkeley, CA
Paper No:
ISPS2016-9624, V001T01A021; 5 pages
Published Online:
September 23, 2016
Citation
Sarabi, S, & Bogy, DB. "Effect of Functional End-Groups on the Lubricant Recovery After Heat-Assisted Magnetic Recording (HAMR) Writing." Proceedings of the ASME 2016 Conference on Information Storage and Processing Systems. ASME 2016 Conference on Information Storage and Processing Systems. Santa Clara, California, USA. June 20–21, 2016. V001T01A021. ASME. https://doi.org/10.1115/ISPS2016-9624
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