Recording medium with a lubricating layer having increased...

Details Recording medium with a lubricating layer having increased... Recording medium with a lubricating layer having increased...

2001-07-10

2004-07-20

Resan, Stevan A. (Department: 1773)

Stock material or miscellaneous articles

Web or sheet containing structurally defined element or...

Physical dimension specified

C428S408000, C428S690000, C428S690000

Reexamination Certificate

active

06764757

ABSTRACT:

BACKGROUND INFORMATION
Most modem information storage systems depend on magnetic recording due to its reliability, low cost, and high storage capacity. The primary elements of a magnetic recording system are the recording medium and the read/write head. Magnetic discs with magnetizable media are used for data storage in almost all computer systems.
In order to maximize storage density on the disc, the flying height between the read/write head and the medium should be minimized. Current magnetic hard disc drives operate with the read/write heads only a few nanometers above the disc surface and at rather high speed, typically a few meters per second. Because the read/write heads can contact the disc surface during operation, a thin layer of lubricant is coated on the disc surface to reduce wear and friction.
Amorphous fluorinated carbon (a-C:F,H) is known for some unique properties such as chemical inertness, good electrical stability, low surface energy and low dielectric constant. It has shown significant superiority in corrosion resistance over the traditional hydrogenated carbon (a-C:H) produced by sputtering and ion beam deposition. Further, a-C:F,H has provided a lower coefficient of friction between the read/write head and the recording medium. The lower coefficient of friction indicates increased wear resistance of the lubricant layer. Lubricants comprising a-C:F,H are disclosed in U.S. Pat. application Ser. No. 09/870,685 filed Jun. 1, 2001, entitled “CORROSION RESISTANT OVERCOAT FOR A COMPONENT OF A RECORDING DEVICE,” the entire contents of which are hereby incorporated by reference.
One problem with the use of a-C:F,H as a solid lubricant arises in the context of thermally or optically assisted magnetic recording. Using a laser beam in association with a writing method for magnetic media can achieve high performance, high density and extended lifetime in data storage applications. However, under laser irradiation, the local temperature generally can rise to temperatures such as 200 to 300° C. It has been observed in thermal modeling that the lubricant layer can easily reach a peak temperature of 200° C. or higher. The thermal stability of conventional a-C:F,H is not sufficient to withstand such temperatures. It has been observed that the dielectric constant of conventional a-C:F,H films begins to change at approximately 250° C. which indicates the film is beginning to degrade. The conventional lubricating layers for magnetic recording are substantially vaporized at 300° C. As a result of the lubricant layer degrading and vaporizing, premature wear of the recording medium, as well as the read/write head may occur.
Therefore, there exists a need for a lubricant layer that shows thermal stability at the high temperatures produced by thermally or optically assisted magnetic recording, while maintaining good wear resistance.
SUMMARY OF THE INVENTION
In accordance with an embodiment of the present invention, a recording medium is provided comprising a substrate, a recording layer disposed on the substrate and a lubricating layer disposed on the recording layer. The lubricating layer comprises fluorinated carbon and a thermally stabilizing dopant.
A method of lubricating a recording medium is also provided in accordance with an embodiment of the present invention. The method comprises the steps of providing a substrate including a recording layer and depositing a lubricating layer onto the recording layer. The lubricating layer comprises fluorinated carbon and a thermally stabilizing dopant.
Also provided in accordance with an embodiment of the present invention is a lubricated article comprising a substrate and a lubricant disposed upon the substrate. The lubricant comprises fluorinated carbon and a dopant selected from the group consisting of N and SiO
2
.


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