Effect of Slider Burnish on Disk Damage During Dynamic Load/Unload

Abstract

Two of the most difficult issues to resolve in current design of head/disk interface in magnetic recording devices are stiction and durability problems. One method of overcoming these problems is by implementing a technology known as load/unload, where the system is designed so that the slider never touches the disk surface. One potential problem with this type of system is slider/disk contact induced disk defects. The objective of this paper is to show that the likelihood of disk scratches caused by head/disk contacts during the load/unload process can be significantly decreased by rounding the edges of the air-bearing surface. Using the resistance method, we observe that head/disk contacts burnish the corners of the slider and thereby decrease exponentially with load/unload cycles. A well burnished slider rarely causes any disk damage thus resulting in an interface with significantly higher reliability. A simple Hertzian contact stress analysis indicates that the contact stress at the head/disk interface can be greatly decreased by increasing the radius of curvature of the air-bearing surface edges.

Direct Measurement of the Laplace Pressure in a Very Thin Liquid Film

“…Orr et al (12) gave a more general and precise expression for Eq. [2], which is applicable to the cases that liquid has different contact angles on the ball and the plane surfaces. Fisher et al (10) found that Eq.…”

“…It is known, from Eq. [2], that meniscus force F is proportional to the surface tension γ and is independent of meniscus radius r . Orr et al (12) gave a more general and precise expression for Eq.…”

“…Fisher et al (10) found that Eq. [2] can apply to a meniscus radius as small as 0.5 nm for cyclohexane and benzene and about 5 nm for water. However, later Christenson (11) showed a different experimental result from that of (10) by using a modified surface force apparatus (SFA) which had a double cantilever instead of a single cantilever.…”

“…The surface tension of condensation of water vapor and/or very thin liquid lubricant film on the hard disk surface causes stiction (1), which often spoils the magnetic storage data. Overcoming stiction is still a formidable task in the magnetic disk drive industry (2). When soft materials such as bacteria flagella are observed by atomic force microscopy (AFM), the water meniscus force leads to an excessive adhesion force, which in turn results in specimen damage (3).…”

Finite Element Simulation of Static Contact of a Slider with Patterned Media

“…Both high flash temperatures and high localized stresses can damage the read/write elements. Several investigations have been conducted in the past to investigate slider/disk contacts (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17) . However, few of these investigations have addressed patterned media or planarized patterned media.…”