Abstract
A heat-assisted magnetic recording (HAMR) is expected for a future high density recording of a hard disk drive. However, a carbon overcoat (COC) composed of diamond-like carbon (DLC) or a lubricant film is possibly damaged when a magnetic medium, i.e. CoPt alloy, is heated at around Curie temperature (Tc) of 600K by a near-field HAMR head. We carried out HAMR simulation experiments by using newly developed Raman spectroscopic systems, composed of plasmonic sensors for surface-enhanced Raman scattering (SERS), a pulsed laser heating, and an in-situ temperature measurement with an intensity ratio of anti-Stokes/Stokes lines. It was found that the heated temperature of the COC is higher than that of the magnetic film, i.e., 580°C and 366°C, respectively. Intensity changes of G-band peak in Raman spectra for DLC films were observed during the pulsed laser heating. The Raman intensity was exponentially decreased by oxidation in air, where time constants were calculated as a parameter of a pulse width. Degradation life of the DLC film can be estimated from a critical pulse width, where the time constant is extrapolated to zero. The estimated pulse width for no degradation was 250μs at the heating temperature of 580°C. The result shows no damage can be estimated in DLC films for HAMR because the effective irradiation time is 5ns and the accumulated irradiation time is 0.5ms in HAMR operations.
| Original language | English |
|---|---|
| Title of host publication | ASME 2016 Conference on Information Storage and Processing Systems, ISPS 2016 |
| Publisher | American Society of Mechanical Engineers |
| ISBN (Electronic) | 9780791849880 |
| DOIs | |
| Publication status | Published - 2016 |
| Event | ASME 2016 Conference on Information Storage and Processing Systems, ISPS 2016 - Santa Clara, United States Duration: 2016 Jun 20 → 2016 Jun 21 |
Other
| Other | ASME 2016 Conference on Information Storage and Processing Systems, ISPS 2016 |
|---|---|
| Country | United States |
| City | Santa Clara |
| Period | 16/6/20 → 16/6/21 |
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ASJC Scopus subject areas
- Control and Systems Engineering
- Hardware and Architecture
- Information Systems
Cite this
Life estimation of carbon overcoat on magnetic media for heatassisted magnetic recording using novel Raman spectroscopy. / Yanagisawa, M.; Kunimoto, Masahiro; Homma, Takayuki.
ASME 2016 Conference on Information Storage and Processing Systems, ISPS 2016. American Society of Mechanical Engineers, 2016.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
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TY - GEN
T1 - Life estimation of carbon overcoat on magnetic media for heatassisted magnetic recording using novel Raman spectroscopy
AU - Yanagisawa, M.
AU - Kunimoto, Masahiro
AU - Homma, Takayuki
PY - 2016
Y1 - 2016
N2 - A heat-assisted magnetic recording (HAMR) is expected for a future high density recording of a hard disk drive. However, a carbon overcoat (COC) composed of diamond-like carbon (DLC) or a lubricant film is possibly damaged when a magnetic medium, i.e. CoPt alloy, is heated at around Curie temperature (Tc) of 600K by a near-field HAMR head. We carried out HAMR simulation experiments by using newly developed Raman spectroscopic systems, composed of plasmonic sensors for surface-enhanced Raman scattering (SERS), a pulsed laser heating, and an in-situ temperature measurement with an intensity ratio of anti-Stokes/Stokes lines. It was found that the heated temperature of the COC is higher than that of the magnetic film, i.e., 580°C and 366°C, respectively. Intensity changes of G-band peak in Raman spectra for DLC films were observed during the pulsed laser heating. The Raman intensity was exponentially decreased by oxidation in air, where time constants were calculated as a parameter of a pulse width. Degradation life of the DLC film can be estimated from a critical pulse width, where the time constant is extrapolated to zero. The estimated pulse width for no degradation was 250μs at the heating temperature of 580°C. The result shows no damage can be estimated in DLC films for HAMR because the effective irradiation time is 5ns and the accumulated irradiation time is 0.5ms in HAMR operations.
AB - A heat-assisted magnetic recording (HAMR) is expected for a future high density recording of a hard disk drive. However, a carbon overcoat (COC) composed of diamond-like carbon (DLC) or a lubricant film is possibly damaged when a magnetic medium, i.e. CoPt alloy, is heated at around Curie temperature (Tc) of 600K by a near-field HAMR head. We carried out HAMR simulation experiments by using newly developed Raman spectroscopic systems, composed of plasmonic sensors for surface-enhanced Raman scattering (SERS), a pulsed laser heating, and an in-situ temperature measurement with an intensity ratio of anti-Stokes/Stokes lines. It was found that the heated temperature of the COC is higher than that of the magnetic film, i.e., 580°C and 366°C, respectively. Intensity changes of G-band peak in Raman spectra for DLC films were observed during the pulsed laser heating. The Raman intensity was exponentially decreased by oxidation in air, where time constants were calculated as a parameter of a pulse width. Degradation life of the DLC film can be estimated from a critical pulse width, where the time constant is extrapolated to zero. The estimated pulse width for no degradation was 250μs at the heating temperature of 580°C. The result shows no damage can be estimated in DLC films for HAMR because the effective irradiation time is 5ns and the accumulated irradiation time is 0.5ms in HAMR operations.
UR - http://www.scopus.com/inward/record.url?scp=84991818144&partnerID=8YFLogxK
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U2 - 10.1115/ISPS2016-9513
DO - 10.1115/ISPS2016-9513
M3 - Conference contribution
AN - SCOPUS:84991818144
BT - ASME 2016 Conference on Information Storage and Processing Systems, ISPS 2016
PB - American Society of Mechanical Engineers
ER -