Understanding Disk Carbon Loss Kinetics for Heat Assisted Magnetic Recording

Jones, Paul M.; Ahner, Joachim; Platt, C. L.; Tang, Huan; Hohlfeld, J.

doi:10.1109/tmag.2013.2285599

Cited by 24 publications

(25 citation statements)

References 19 publications

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“…2 , the DLC:H protection coatings on the disks and heads will need to remain thermally stable. [23][24][25][26][27][28] In HAMR, an anisotropic magnetic material such as FePt with L1 0 phase is used as the recording medium on the disk. This magnetic medium is heated above its Curie temperature between 450 C and 650 C using a near-field plasmonic antenna on the head.…”

Section: Introductionmentioning

confidence: 99%

Complete characterization by Raman spectroscopy of the structural properties of thin hydrogenated diamond-like carbon films exposed to rapid thermal annealing

Rose

Wang

Smith

et al. 2014

Journal of Applied Physics

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Gold nanoparticle formation in diamond-like carbon using two different methods: Gold ion implantation and codeposition of gold and carbon J. Appl. Phys. 112, 074312 (2012) We have demonstrated that multi-wavelength Raman and photoluminescence spectroscopies are sufficient to completely characterize the structural properties of ultra-thin hydrogenated diamondlike carbon (DLC:H) films subjected to rapid thermal annealing (RTA, 1 s up to 659 C) and to resolve the structural differences between films grown by plasma-enhanced chemical vapor deposition, facing target sputtering and filtered cathodic vacuum arc with minute variations in values of mass density, hydrogen content, and sp 3 fraction. In order to distinguish unequivocally between films prepared with different density, thickness, and RTA treatment, a new method for analysis of Raman spectra was invented. This newly developed analysis method consisted of plotting the position of the Raman G band of carbon versus its full width at half maximum. Moreover, we studied the passivation of non-radiative recombination centers during RTA by performing measurements of the increase in photoluminescence in conjunction with the analysis of DLC:H networks simulated by molecular dynamics. The results show that dangling bond passivation is primarily a consequence of thermally-induced sp 2 clustering rather than hydrogen diffusion in the film. V C 2014 AIP Publishing LLC. [http://dx

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Section: Introductionmentioning

confidence: 99%

Complete characterization by Raman spectroscopy of the structural properties of thin hydrogenated diamond-like carbon films exposed to rapid thermal annealing

Rose

Wang

Smith

et al. 2014

Journal of Applied Physics

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“…Similar carbon loss by localized heating was previously observed for PECVD-based CH x COC at greater thicknesses of 5 ± 2 nm. 15 Apart from the D and G peaks, the Raman spectra of SC I at periphery displayed an additional peak at ∼1455 cm −1 . This peak might be due to the superposition of different carbon phases from nonirradiated and irradiated regions at the periphery.…”

Section: Resultsmentioning

confidence: 96%

“…Recent studies have shown that these overcoats degrade when they are subjected to HAMR-like conditions, such as rapid thermal annealing and localized heating. 14,15 Since the media temperature rises to 600−700 K, hydrogen is easily depleted from the carbon−hydrogen skeleton present in CH x overcoats. 2,14 Subsequently, rearrangement occurs in the bonding of the carbon atoms and leads to increased graphitization/aromatization of the carbon network.…”

Section: Introductionmentioning

confidence: 99%

Probing the Role of Carbon Microstructure on the Thermal Stability and Performance of Ultrathin (<2 nm) Overcoats on L1₀ FePt Media for Heat-Assisted Magnetic Recording

Kundu

Dwivedi

Satyanarayana

et al. 2014

ACS Appl. Mater. Interfaces

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An understanding of the factors influencing the thermal stability of ultrathin carbon overcoats (COCs) is crucial for their application in heat-assisted magnetic recording (HAMR) at densities ≥ 1 Tb/in(2). Two types of non-hydrogenated ultrathin (∼1.5 nm) COCs were investigated after being subjected to laser-induced localized heating (at temperatures > 700 K) as envisaged in HAMR. Filtered cathodic vacuum arc (FCVA)-processed carbon with tuned C(+) ion energies of 350 eV followed by 90 eV provides significantly higher sp(3) C-C hybridization than magnetron sputter deposition even at very low thicknesses of ∼1.5 nm. As a result, the FCVA-deposited ultrathin carbon overcoats displayed excellent thermal stability along with improved wear and corrosion resistance. On the other hand, the sputtered carbon exhibited carbon loss and topographical and structural changes after laser irradiation owing to lower sp(3) hybridization. Therefore, this study highlights the pivotal role of carbon microstructure, primarily sp(3) hybridization, in non-hydrogenated carbon overcoats to maintain excellent thermal stability during the recurring high-temperature cycles in a HAMR process.

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“…Therefore, it is of considerable importance to make a COC layer with both excellent recording performance and high thermal stability. [3][4][5][6] Previous research studied the effect of laser heating rate and laser heating duration on carbon depletion of a HAMR drive using an external laser source. [7] It was found that laser heating induces surface topographical and structure changes for a-C:N x overcoat.…”

Section: Introductionmentioning

confidence: 99%

“…Another study used an optical pump-probe technique to measure the laser-induced magnetization change in HAMR media, which shows depressions or holes in the surface due to COC graphitization or oxidation. [5] Other research compared the thermal stability of COC synthesized by different techniques, such as filtered cathodic vacuum arc and chemical vapor deposition (CVD) [3,6] Results indicate that laser heating altered the structure of both COC thin films through sp 3 -to-sp 2 transformation and sp 2 clustering. However, research on laser-induced changes of media COC in a short period of exposure time with small spot using full integrated diode (FID) HAMR heads is still limited.…”

Section: Introductionmentioning

confidence: 99%

Effect of Carbon Overcoat on Heat-Assisted Magnetic Recording Performance

Sinha

Rismani-Yazdi

et al. 2015

IEEE Trans. Magn.

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Heat-assisted magnetic recording (HAMR) is a promising approach for enabling large increases in the magnetic data storage density. Amorphous carbon is the principal overcoat material of thin-film disks and magnetic heads in HAMR systems. In the present paper, we investigated the recording performance of media with a chemical vapor deposition (CVD) carbon overcoat and a sputtered carbon overcoat. We observed that the carbon type has a significant impact on HAMR recording performance and heat absorption. Tunneling current atomic force microscopy (TUNA-AFM) analysis results show higher surface roughness and peak current in the disk with sputtered carbon. Track profile and magnetic signal measurement results indicate 90% of the optimized laser current is not enough to fully write the disk with CVD carbon, while the tracks on the sputtered carbon disk can be written using the same laser current. The difference in the two types of carbon overcoat can be attributed to the difference in the carbon bonding structure, the optical and electrical properties, the roughness, and the heat absorption behavior.Index Terms -Heat-assisted magnetic recording (HAMR), carbon overcoat (COC), laser heating 0018-9464 (c)

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Understanding Disk Carbon Loss Kinetics for Heat Assisted Magnetic Recording

Cited by 24 publications

References 19 publications

Complete characterization by Raman spectroscopy of the structural properties of thin hydrogenated diamond-like carbon films exposed to rapid thermal annealing

Complete characterization by Raman spectroscopy of the structural properties of thin hydrogenated diamond-like carbon films exposed to rapid thermal annealing

Probing the Role of Carbon Microstructure on the Thermal Stability and Performance of Ultrathin (<2 nm) Overcoats on L1₀ FePt Media for Heat-Assisted Magnetic Recording

Effect of Carbon Overcoat on Heat-Assisted Magnetic Recording Performance

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Understanding Disk Carbon Loss Kinetics for Heat Assisted Magnetic Recording

Cited by 24 publications

References 19 publications

Complete characterization by Raman spectroscopy of the structural properties of thin hydrogenated diamond-like carbon films exposed to rapid thermal annealing

Complete characterization by Raman spectroscopy of the structural properties of thin hydrogenated diamond-like carbon films exposed to rapid thermal annealing

Probing the Role of Carbon Microstructure on the Thermal Stability and Performance of Ultrathin (<2 nm) Overcoats on L10 FePt Media for Heat-Assisted Magnetic Recording

Effect of Carbon Overcoat on Heat-Assisted Magnetic Recording Performance

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Probing the Role of Carbon Microstructure on the Thermal Stability and Performance of Ultrathin (<2 nm) Overcoats on L1₀ FePt Media for Heat-Assisted Magnetic Recording