Paper AS-ThP16
Analysis of Doped Amorphous Carbon Film for Heat-assisted Magnetic Recording Application

Thursday, October 31, 2013, 6:00 pm, Room Hall B

Heat-assisted magnetic recording (HAMR) uses a laser-magnetic head integrated system to rapidly heat a localized recording area of the medium above its Curie temperature in order to reduce its coercivity below that of the applied magnetic field during the recording process.^1,2 Unlike perpendicular recording, HAMR is not limited by the superparamagnetic effect associated with magnetic particle instability and low signal-to-noise ratio.² However, localized laser heating may affect the thermal stability of the protective carbon coating on the hard disk.^1,2,3 To examine the effect of heating on carbon film stability, three types of a-C films of 5nm thickness have been studied; (1) single layer a-CH film (2) single layer a-CN film and (3) double layer a-CN/CH film. This paper discusses the relationship between thermal heating and structural evolution of the carbon films. XPS was employed to investigate the sp² and sp³ carbon formation related to heating. The variation in sp²/sp³ content and the dispersion of D and G peaks in Raman spectra both prove that there is a structural change in the carbon films after heat. Differences in sp²/sp³ ratio shows that the carbon structure of a-CN/CH film is thermally more stable than a-CH and a-CN films. TOF-SIMS results reveal that the top a-CN capping layer of the double layer a-CN/CH film structure is able to preserve the C-H bonding within the a-CH under layer. This result in the carbon structure of double layer a-CN/CH film exhibiting better thermal stability compared to single layer a-CH film.

Reference:

1 N. Wang and K. Komvopoulos, IEEE Transactions on Magnetics 47, 2277 (2001)

2 S.N. Piramanayagam and K.Srinivasan, J. Magnetism and Magnetic Materials 321, 485 (2009)

3 W. Zhang, Y. Xia, J. Ju, Y. Fan, Z. Fang, L. Wang, Z. Wang, Solid State Communication 123, 97 (2002)