Seagate Technology Incorporated

Hitachi Global Storage Technologies Netherlands B.v.

Seagate Technologies, Inc.

Bruno Jacques Marchon

Jing Gui

Zine-Eddine Boutaghou

Qing Dai

Huazhou Lou

Dipeshkumar J Purani

David Gerard Wobbe

David Braunstein

Tae Young Kim

Described are hard disk drives that include a low density atmosphere, with which is included a passivating gas, and methods of using these hard disk drives and methods of assembling these hard disk drives.

Hard disk drive with low density atmosphere

A method is presented for measuring the height of an air-bearing separating a flying component from a rotating surface using physical deformation of a small amount of material deposited on the surface. One embodiment of the invention is a method of measuring the fly-height of a slider using physical deformation of material deposited on the disk. Small amounts of the deformable material such as a viscoelastic lubricant are placed on a limited area of the disk so that the slider can otherwise fly normally. The slider's fly-height is established over the unaltered portion of the disk, then the slider impacts the deformable material. This process results in the deformable material being flattened or removed above the fly-height of the slider. The height of the remaining material is then measurable as the fly-height.

Slider fly-height measurement using viscoelastic material

In a disc drive with a disc spun by a motor and a head positionable over the disc, a disc drive controller alternately leaves the head landed on successive landing spots in a landing zone on the disc for selected stop intervals to remove an increment of lubricant from the head with each stop and then automatically lifts the head by spinning the disc for selected run intervals between the stop intervals so the head does not stick to the disc.

Lubricant control in disc drive

Disclosed is a perfluoropolyether (PFPE) lubricant comprising less than about 10 percent PFPE molecules having a molecular weight lower than about 2000 Daltons, and wherein the average molecular weight of the lubricant is greater than about 5000 Daltons. Such a lubricant comprises less than about 15 percent PFPE molecules having a moleuclar weight greater than about 10,000 Daltons. Also disclosed is a thin film magnetic disc comprising a recording surface and a PFPE lubricant in contact with the recording surface. The recording surface of such a thin film magnetic disc can be adapted to magnetically record information via an air bearing read/write head. The recording surface can be smooth. The disc can further comprise a rough-surfaced landing zone inward of the recording surface, wherein the PFPE lubricant is in contact with the landing zone. Also disclosed is a method of lubricating a thin film magnetic disc. The method can comprise applying a narrow, high molecular weight fractionated PFPE lubricant to the disc. In addition, a method of preparing a PFPE lubricant for use with a thin film magnetic disc is disclosed. The method can comprise fractionating a PFPE lubricant to include less than about 10 percent PFPE molecules having a molecular weight lower than about 2000 Daltons. The average molecular weight of such a lubricant after fractionation is greater than about 5000 Daltons.

High molecular weight fractioned lubricant for use with thin film

A quantitative stiction model for HDI has been proposed, which takes into account local redistribution of lubricant and its effect on meniscus formation. Equations for calculating stiction have been obtained for three distinct situations, depending on the ratio of the interface separation to the lubricant film thickness and the interactions among contacting asperities. The model has been applied to HDIs consisting of either regular or random texture. The model predicts that the relationship between stiction and the real area of contact is not necessarily monotonic. Instead, stiction exhibits a broad minimum for intermediate values of true contact. This prediction is consistent with some of the experimental results reported in the literature. The model also suggests that the role of various roughness parameters on stiction are not independent of one another. To minimize stiction and maximize reliability under a given flyability constraint, the asperity height, radius and density need to be considered simultaneously.

Stiction model for a head-disc interface of a rigid disc drive

Lubricated magnetic recording discs are provided by vapor deposition of narrow molecular weight fractions of a terminally functionalized perfluoropolyether. The coatings are found to provide stable lubrication over extended periods of time in CSS cycles.

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Palo Alto, CA, United States of America

Bruno Jacques Marchon