Air-Bearing Design Towards Highly Stable Head–Disk Interface at Ultralow Flying Height

Liu, Bo; Yu, Shengkai; Zhang, Mingsheng; Gonzaga, Leonard; Li, Hui; Liu, Jin; Ma, Yansheng

doi:10.1109/tmag.2006.888366

Cited by 48 publications

(18 citation statements)

References 11 publications

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“…Slider flying height in hard disk drives is extremely low [1,8]. It is usually much shorter than the mean-free-path of the lubricant vapor molecules and even shorter than the mean-free-path of air molecules.…”

Section: Lubricant Film Formation Process In Vapor Lubricationmentioning

confidence: 99%

A Theoretical Study of Vapor Lubrication for Heat Assisted Magnetic Recording

Liu

2008

Tribol Lett

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Heat assisted magnetic recording (HAMR) is a promising technique to overcome the superparamagnetic limit to further increase the areal recording density of hard disk drives. However, HAMR brings about serious problems to the slider-disk interface, such as lubricant depletion on disk surface caused by laser heating. It is proposed to overcome the lubricant depletion problem by using vapor lubrication. The lubricant film formation process on disk surface in vapor lubrication is studied theoretically based on fundamental adsorption and desorption theories. The controlling parameters of lubricant film thickness and film formation time are identified. It is found that the lubricant film thickness is controlled mainly by lubricant vapor pressure and molecular weight. The film formation time can be shortened by using low molecular weight lubricant and high temperature lubricant vapor.

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Section: Lubricant Film Formation Process In Vapor Lubricationmentioning

confidence: 99%

A Theoretical Study of Vapor Lubrication for Heat Assisted Magnetic Recording

Liu

2008

Tribol Lett

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“…When recording density increases to 1 Tb/in2, the flying height is only about 2.5 nm (Wood 2000;Liu et al 2007). Both intermolecular force (IMF) and electrostatic force (ESF) increase prominently at such low flying height, these forces will play more important role in the balance of head disk interface (HDI) and make HDI unstable (Wu and Bogy 2002;Li et al 2005;Zhang and Nakajima 2003;Lee and Polycarpou 2004;Deoras and Talke 2000;Wei et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Approaches to reduce effect of short-range interactions in head disk interface

2009

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Different approaches to reduce the effect of short-range interactions on slider's flying stabilityreduction of pad width at trailing edge and increase of air pressure on trailing pad-are compared for the flying stability and flying height modulation. The static and dynamic simulations show both approaches can reduce the effect of intermolecular force and electrostatic force on the slider's flying stability. On the other hand, the increase of air pressure on trailing pad can also reduce the flying height modulation caused by disk waviness, but reduction of pad width at trailing edge increases the flying height modulation. Hence, the increase of air pressure on trailing pad is more suitable for the application of the ultra low flying height in hard disk drives.

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“…Currently, the minimum spacing between the flying head/ slider and the rotating disk in hard disk drives (HDDs) is within the order of several nanometers (Gupta and Bogy 2005;Juang et al 2007;Liu et al 2007;Shi et al 2009). In the analysis of ultra-thin gas film lubrication problems, the effects of gas rarefaction and surface accommodation coefficients (ACs) on the static characteristics (flying characteristics when the head/slider is flying in a stable operation state without considering time) of the head/slider become significant.…”

Section: Introductionmentioning

confidence: 99%

Simplified molecular gas film lubrication equation and accommodation coefficient effects

Shi

Yang

2011

Microsyst Technol

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As the spacing between the flying head/slider and the rotating disk in hard disk drives (HDDs) continues to decrease, the interaction between the molecular gas and the surfaces of the disk and the head/slider becomes significant. The influence of surface accommodation coefficient (AC) is an important factor to govern the static characteristics of the head/slider. Starting from the polynomial logarithm fitting equations of Poisueille flow rate and Couette flow rate, a new simplified molecular gas film lubrication (MGL) equation is proposed to simulate the ultra-thin air bearing film in HDDs. The new MGL equation is simpler than that of the polynomial logarithm form of MGL equation. The new approach produces very good approximations for both Poisueille flow rate and Couette flow rate with very little differences to those based on the original MGL equation. The new simplified MGL equation is solved by using a meshless method, called least square finite difference (LSFD) method. Effects of ACs on the static characteristics of air bearing films in HDDs with ultra-low flying heights are investigated. Numerical results show that effects of ACs on the static characteristics are significant for the case of symmetric molecular interaction. On the other hand, effects of ACs at the disk surface on the static characteristics are significant for the case of nonsymmetric molecular interaction, while effects of ACs at the slider surface on the static characteristics are weak.

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Air-Bearing Design Towards Highly Stable Head–Disk Interface at Ultralow Flying Height

Cited by 48 publications

References 11 publications

A Theoretical Study of Vapor Lubrication for Heat Assisted Magnetic Recording

A Theoretical Study of Vapor Lubrication for Heat Assisted Magnetic Recording

Approaches to reduce effect of short-range interactions in head disk interface

Simplified molecular gas film lubrication equation and accommodation coefficient effects

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