Effects of Oxygen on Smear Formation in Heat Assisted Magnetic Recording System

Heat-assisted magnetic recording (HAMR) is expected to be a realistic next-generation technology for increasing the recording density of hard disks. However, the magnetic layer is heated above the Curie temperature, and, as a result, the heated lubricant is desorbed from the disk by decomposition an...

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Bibliographic Details
Published in:Tribology Online 2022/12/31, Vol.17(4), pp.348-355
Main Authors: Yakata, Kenji, Kurafuji, Hiroshi, Tani, Hiroshi, Lu, Renguo, Koganezawa, Shinji, Kawada, Shouhei, Tagawa, Norio
Format: Article
Language:English
Subjects:
Chains
Curie temperature
Decomposition
Disks
environmental gas
Gas chromatography
hard disk drives
head-disk interface
heat-assisted magnetic recording
Helium
Laser beam heating
Magnetic recording
Mass spectrometry
Oxygen
perfluoropolyether
Pyrolysis
pyrolysis gas chromatography-mass spectrometry
smear
Thermal decomposition
Thin films
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Summary:Heat-assisted magnetic recording (HAMR) is expected to be a realistic next-generation technology for increasing the recording density of hard disks. However, the magnetic layer is heated above the Curie temperature, and, as a result, the heated lubricant is desorbed from the disk by decomposition and evaporation, which causes a problem as it adheres to the air-bearing surface (ABS) as a smear. In this study, pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) analysis was performed in helium and air environments to investigate the decomposition mechanism of perfluoropolyether (PFPE) lubricant D-4OH by heating and in the presence of oxygen. In the helium environment, thermal decomposition of the end groups was confirmed at 350°C and above with a possibility of main chain decomposition at 450°C. In the air environment, decomposition of the end group was confirmed at 250°C and above, and decomposition of the main chain was confirmed at 450°C. Experiments using a pin-on-disk tester were conducted to confirm what happens to the area of smear when a thin film of D-4OH lubricant coated on an actual disk is laser heated. As a result, it was confirmed that the area of smear decreased even at an oxygen concentration of 5%.
ISSN:1881-2198
1881-218X
1881-2198
DOI:10.2474/trol.17.348