Depletion of Monolayer Liquid Lubricant Films Induced by Laser Heating in Thermally Assisted Magnetic Recording

• Published in: Tribology letters Vol. 47; no. 1; pp. 123 - 129
• Main Authors: Tagawa, Norio, Miki, Takao, Tani, Hiroshi
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.07.2012; Springer Nature B.V
• Subjects: Chemistry and Materials Science; Corrosion and Coatings; Critical temperature; Depletion; Desorption; Diamond-like carbon films; Film thickness; Heating rate; Laser beam heating; Lasers; Lubricant films; Lubricants & lubrication; Magnetic recording; Materials Science; Monolayers; Nanotechnology; Original Paper; Physical Chemistry; Pulsed lasers; Surfaces and Interfaces; Theoretical and Applied Mechanics; Thin Films; Tribology; Head–disk interface; Heating rate; Lubricant depletion; Desorption; Decomposition; TPD spectroscopy; Thermally assisted magnetic recording; Pulsed-laser heating
• ISSN: 1023-8883; 1573-2711
• DOI: 10.1007/s11249-012-9968-x

In this study, lubricant depletion due to high-frequency pulsed-laser heating, with a heating rate of ~10 8 –10 9  K/s, was investigated for lubricant films with thicknesses of greater than and less than one monolayer. The conventional lubricants, Zdol2000 and Ztetraol2000, were used. It was found that the critical temperature at which the lubricants begin to deplete was strongly dependent on the lubricant film thickness. For lubricant film thicknesses of less than one monolayer, this temperature was approximately 170 °C higher than that for thicknesses of greater than one monolayer. To analyze the lubricant depletion mechanism, we examined the tested lubricant films, using temperature-programmed desorption (TPD) spectroscopy, in which the heating rate was 0.3 K/s. It was found that the lubricant depletion characteristics could be explained using the experimental TPD results for the tested lubricant films. The depletion mechanism involves the desorption or decomposition of the lubricant molecules, which interact with the diamond-like carbon thin films when the lubricant film thickness is less than one monolayer. Therefore, we concluded that the TPD results were highly effective for evaluating the lubricant depletion characteristics induced by rapid laser heating, even though the heating rates are substantially different.