Life Estimation of Carbon Overcoat on Magnetic Media for Heat-Assisted Magnetic Recording Using Novel Raman Spectroscopy

2016 ◽  
Author(s):  
M. Yanagisawa ◽  
M. Kunimoto ◽  
T. Homma
Keyword(s):  
Magnetic Recording ◽  
Laser Heating ◽  
Pulse Width ◽  
Heating Temperature ◽  
Irradiation Time ◽  
Near Field ◽  
Pulsed Laser ◽  
Carbon Overcoat ◽  
Heat Assisted Magnetic Recording ◽  
Pulsed Laser Heating

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.

Performance benefits from pulsed laser heating in heat assisted magnetic recording

2014 ◽  
Vol 115 (17) ◽  
pp. 17B701 ◽  
Author(s):  
B. X. Xu ◽  
Z. H. Cen ◽  
J. H. Goh ◽  
J. M. Li ◽  
Y. T. Toh ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Laser Heating ◽  
Pulsed Laser ◽  
Heat Assisted Magnetic Recording ◽  
Pulsed Laser Heating

Laser-Heating-Induced Damage to Ultrathin Carbon Overcoat in Heat-Assisted Magnetic Recording

2013 ◽  
Vol 53 (1) ◽  
pp. 303-310 ◽  
Author(s):  
Y. S. Ma ◽  
Y. J. Man ◽  
M. Shakerzadeh ◽  
H. L. Seet ◽  
R. Ji ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Laser Heating ◽  
Carbon Overcoat ◽  
Heat Assisted Magnetic Recording

HAMR Emulation on Carbon Overcoat and Lubricant for Near Field Transducer and Magnetic Media Using Surface-Enhanced Raman Sensors

2017 ◽  
Author(s):  
M. Yanagisawa ◽  
M. Kunimoto ◽  
T. Homma
Keyword(s):  
Laser Heating ◽  
Heating Temperature ◽  
Near Field ◽  
In Situ Observation ◽  
Magnetic Media ◽  
Spectral Change ◽  
Plasmonic Sensor ◽  
Carbon Overcoat ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

A plasmonic sensor is used for emulation of near field transducer (NFT). Some overcoat films (thickness of 1nm) were coated on Au nanoparticles (NPs) on a convex quartz glass substrate (plasmonic sensor). Heating behavior of the films was examined by laser heating using novel Raman spectroscopic tools, i.e. surface-enhanced Raman scattering (SERS) with the plasmonic sensor, a continuous laser heating tool, in-situ observation of spectra and temperature with a high speed time-resolved measurement. The heating temperature of tetrahedral carbon (ta-C) film in He gas is lower than that in air. This is because the thermal conductivity of He is larger than air. Few spectral change of ta-C film (thickness of 1nm) on Au NP’s is observed except initial change in around 100 s at the temperature around 500 °C, which corresponds to the temperature of the carbon overcoat (COC) for the media temperature of 327 °C (600K, Currie temperature for CoPt alloy). Some carbide films, i.e. SiC, TiC, and WC, showed high heat resistance, that is, few spectral change was observed. It is found that lubricant is evaporated from the COC on magnetic media and transferred to the plasmonic sensor.

Laser Heating-Induced Degradation of Ultrathin Media Carbon Overcoat for Heat-Assisted Magnetic Recording

2016 ◽  
Vol 52 (2) ◽  
pp. 1-6 ◽  
Author(s):  
Yansheng Ma ◽  
Rong Ji ◽  
Yijun Man ◽  
Maziar Shakerzadeh ◽  
Rongyan Zheng ◽  
...  
Keyword(s):  
Magnetic Recording ◽  
Laser Heating ◽  
Carbon Overcoat ◽  
Heat Assisted Magnetic Recording

Pulsed laser heating of soot: morphological changes

Carbon ◽  
1999 ◽  
Vol 37 (2) ◽  
pp. 231-239 ◽  
Author(s):  
Randy L Vander Wal ◽  
Mun Y Choi
Keyword(s):  
Laser Heating ◽  
Morphological Changes ◽  
Pulsed Laser ◽  
Pulsed Laser Heating

Thermal decomposition and desorption of PFPE Zdol on a DLC substrate using quartic bond interaction potential

RSC Advances ◽  
2015 ◽  
Vol 5 (85) ◽  
pp. 69651-69659 ◽  
Author(s):  
S. K. Deb Nath
Keyword(s):  
Thermal Decomposition ◽  
Interaction Potential ◽  
Magnetic Recording ◽  
Magnetic Layer ◽  
Hard Disk ◽  
Carbon Overcoat ◽  
Heat Assisted Magnetic Recording ◽  
Reading And Writing ◽  
Bond Interaction ◽  
Laser Rays

In heat assisted magnetic recording (HAMR) system, heating of the hard disk magnetic layer is carried out by applying laser rays during the movement of the read/write head over the carbon overcoat for the purpose of reading and writing on its magnetic layer.

Thermal Modeling of the Cavity in Pulsed Excimer Laser Calorimeters

2000 ◽  
Author(s):  
D. H. Chen ◽  
Z. M. Zhang
Keyword(s):  
Laser Heating ◽  
Average Power ◽  
Pulsed Laser ◽  
Thermal Response ◽  
Element Model ◽  
Electrical Heating ◽  
Deep Ultraviolet ◽  
Simplified Finite Element Model ◽  
193 Nm ◽  
Pulsed Laser Heating

Abstract A simplified finite element model is built to study the thermal response of the 193-nm pulsed-laser calorimeter. The nonequivalence between pulsed-laser heating and electrical heating is estimated to be 0.46% at the thermocouple locations by comparing the calibration factors for average-power laser heating and electrical heating. This study should help the development of calibration and measurement standards in pulsed energy measurements for deep ultraviolet excimer lasers that are important for photolithographic and materials processing applications.

Effect of pulsed laser heating on the magnetic properties of the amorphous alloy Fe76Si13B11

2009 ◽  
Vol 108 (2) ◽  
pp. 125-130 ◽  
Author(s):  
V. V. Girzhon ◽  
A. V. Smolyakov ◽  
N. G. Babich ◽  
M. P. Semen’ko
Keyword(s):  
Magnetic Properties ◽  
Amorphous Alloy ◽  
Laser Heating ◽  
Pulsed Laser ◽  
Pulsed Laser Heating
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