Study on Lubricant Depletion Induced by Laser Heating in Thermally Assisted Magnetic Recording Systems: Effect of Lubricant Thickness and Bonding Ratio

Tagawa, Norio; Andoh, Hideki; Tani, Hiroshi

doi:10.1007/s11249-009-9533-4

Cited by 60 publications

(27 citation statements)

References 4 publications

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“…As the HDD industry moves towards the introduction of HAMR recording technologies, there is a high demand for the HDI to demonstrate robustness at higher temperatures [30,[61][62][63]. If the current disk overcoat and lubricant films are not capable of withstanding the high recording temperature (>500 ∘ C), new materials will be needed.…”

Section: Tribology and Hdi Challenges For Alternate Technologiesmentioning

confidence: 99%

The Head-Disk Interface Roadmap to an Areal Density of Tbit/in²

Marchon

Pitchford

Hsia

et al. 2013

Advances in Tribology

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This paper reviews the state of the head-disk interface (HDI) technology, and more particularly the head-medium spacing (HMS), for today's and future hard-disk drives. Current storage areal density on a disk surface is fast approaching the one terabit per square inch mark, although the compound annual growth rate has reduced considerably from ∼100%/annum in the late 1990s to 20-30% today. This rate is now lower than the historical, Moore's law equivalent of ∼40%/annum. A necessary enabler to a high areal density is the HMS, or the distance from the bottom of the read sensor on the flying head to the top of the magnetic medium on the rotating disk. This paper describes the various components of the HMS and various scenarios and challenges on how to achieve a goal of 4.0-4.5 nm for the 4 Tbit/in 2 density point. Special considerations will also be given to the implication of disruptive technologies such as sealing the drive in an inert atmosphere and novel recording schemes such as bit patterned media and heat assisted magnetic recording.

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Section: Tribology and Hdi Challenges For Alternate Technologiesmentioning

confidence: 99%

The Head-Disk Interface Roadmap to an Areal Density of Tbit/in²

Marchon

Pitchford

Hsia

et al. 2013

Advances in Tribology

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“…In HAMR, the magnetic film disk is heated to several hundred degrees Celsius, and thus, the protective diamond-like carbon (DLC) film on the disk surface and the perfluoropolyether lubricant film (PFPE) are also heated to high temperatures. Therefore, structural changes in or burning of the DLC protective film and the possibility of evaporation of the PFPE lubricant film are matters of concern [2][3][4][5]. Moreover, with the heating of the PFPE lubricant film, there is also an increased risk of the lubricant pickup adhering to the magnetic head slider or the depletion of the lubricant film due to contact with the magnetic head, which is present at a flying height of less than 10 nm.…”

Section: Introductionmentioning

confidence: 99%

“…The depletion characteristics of ultra-thin liquid lubricant films could be explained by the experimental results obtained from thermogravimetric analyses for each bulk lubricant material. Tagawa et al [4] investigated the effects of the lubricant film thickness and lubricant-bonding ratio on lubricant depletion. The lubricant depletion characteristics were found to depend largely on the lubricant film thickness.…”

Section: Introductionmentioning

confidence: 99%

Improvement in Heat Resistance of Perfluoropolyether Lubricant Films on Magnetic Disks by UV Irradiation with a Bias Voltage on the Disk Surface

et al. 2016

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Our previous study confirmed that the photoelectron-assisted ultraviolet (UV) irradiation with a bias voltage between the magnetic disk and the counter electrode above the disk surface increased the bonded ratio of a perfluoropolyether lubricant film on the disk surface. In this study, two types of lubricant materials (Fomblin Z-tetraol and Moresco ADOH) were prepared and coated on disks. After coating the lubricant films, UV irradiation of the lubricated disk surface was performed using the normal process and the photoelectron-assisted process, and the depletions of these lubricant films were compared using the pin-on-disk test with the laser heating function. The results showed that the lubricant film treated with normal UV irradiation without the bias voltage showed a deeper depletion of the lubricant film than that treated with photoelectron-assisted UV irradiation, and the ADOH film showed a shallower depletion than the Z-tetraol film. However, the molecular weight distributions of the ADOH films on DLC surfaces treated by UV irradiation were compared using time-of-flight secondary ion mass spectroscopy, and the film treated with photoelectron-assisted UV irradiation did not change owing to dissociation after photoelectron capture. Photoelectron-assisted UV irradiation led to the decomposition of the cyclo-triphosphazene end groups. Therefore, it is assumed that the depletion of lubricant films treated with photoelectron-assisted UV irradiation was reduced, since the bonding strength to the DLC surface increased because of the greater decomposition of end groups.

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“…However, HAMR also causes some serious problems to the head-disk interface. One big problem is the lubricant evaporation and depletion caused by the rapid laser heating, which has been studied extensively in recent years [1][2][3][4][5][6][7][8]. For example, Wu [2,3] developed a model to simulate the lubricant depletion under a scanning laser beam in a HAMR system, incorporating the effects of evaporation, thermocapillary stress, thermoviscosity, and disk structure on the lubricant depletion.…”

Section: Introductionmentioning

confidence: 99%

“…For example, Wu [2,3] developed a model to simulate the lubricant depletion under a scanning laser beam in a HAMR system, incorporating the effects of evaporation, thermocapillary stress, thermoviscosity, and disk structure on the lubricant depletion. Tagawa et al [4][5][6][7] conducted experiments to study the lubricant evaporation and depletion under different lubricant materials, film thicknesses, and bonding ratios in HAMR. Some conventional lubricants were used and the lubricant depletion was found to largely depend on the lubricant film thickness and bonding ratio.…”

Section: Introductionmentioning

confidence: 99%

A Model for Laser Induced Lubricant Depletion in Heat-Assisted Magnetic Recording

et al. 2011

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The lubricant evaporation caused by the rapid laser heating is always a big concern in heat-assisted magnetic recording. In this article, we develop an empirical equation based on the existing measurement data to describe the relation between the evaporation coefficient of lubricant and temperature on the disk surface. The evaporation coefficient of lubricant is found to decrease from *1.0 to *0.003 for the temperature range from 406 to 512 K and follow the trend given by the Arrhenius formula. By incorporating this formula into a previously established evaporation model, we can get a new model, which enables us to predict the lubricant evaporation and depletion caused by the rapid laser heating more accurately than ever.

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Study on Lubricant Depletion Induced by Laser Heating in Thermally Assisted Magnetic Recording Systems: Effect of Lubricant Thickness and Bonding Ratio

Abstract: In this study, we have carried

Cited by 60 publications

References 4 publications

The Head-Disk Interface Roadmap to an Areal Density of Tbit/in²

The Head-Disk Interface Roadmap to an Areal Density of Tbit/in²

Improvement in Heat Resistance of Perfluoropolyether Lubricant Films on Magnetic Disks by UV Irradiation with a Bias Voltage on the Disk Surface

A Model for Laser Induced Lubricant Depletion in Heat-Assisted Magnetic Recording

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Study on Lubricant Depletion Induced by Laser Heating in Thermally Assisted Magnetic Recording Systems: Effect of Lubricant Thickness and Bonding Ratio

Abstract: In this study, we have carried

Cited by 60 publications

References 4 publications

The Head-Disk Interface Roadmap to an Areal Density of Tbit/in2

The Head-Disk Interface Roadmap to an Areal Density of Tbit/in2

Improvement in Heat Resistance of Perfluoropolyether Lubricant Films on Magnetic Disks by UV Irradiation with a Bias Voltage on the Disk Surface

A Model for Laser Induced Lubricant Depletion in Heat-Assisted Magnetic Recording

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The Head-Disk Interface Roadmap to an Areal Density of Tbit/in²

The Head-Disk Interface Roadmap to an Areal Density of Tbit/in²