Strain imaging of a magnetic layer formed on an air bearing surface of a hard disk drive head for perpendicular recording

During normal operations of a hard disk drive (HDD), a slider flies over the surface of a spinning disk lifted by a thin layer of air. The disk surface is coated by a molecularly-thin layer of lubricant to protect it against corrosion and reduce wear on the read/write head. The flying height of the slider should be as small as possible in order to achieve higher recording densities. In current HDDs the head-to-disk spacing is on the order of 1–3 nm [1]. At this ultra-low spacing lubricant from the disk often transfers to the slider’s air bearing surface (ABS) forming a thin film that imposes a significant degradation on its performance. Problems such as head instabilities, flying stiction, disk lubricant depletion and increase in head-disk spacing occur when lubricant is present on the ABS [2]. To avoid this condition, modern sliders should be able to remove the lubricant from the ABS as fast as possible. Hence, it is necessary to have a thorough understanding of the lubricant flow process and its driving forces.

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Lubricant Migration Simulations on the Flying Head Slider Air-Bearing Surface in a Hard Disk Drive

IEEE Transactions on Magnetics ◽

10.1109/tmag.2007.902975 ◽

2007 ◽

Vol 43 (9) ◽

pp. 3710-3715 ◽

Cited By ~ 9

Author(s):

Hiroyuki Kubotera ◽

David B. Bogy

Keyword(s):

Hard Disk Drive ◽

Hard Disk ◽

Disk Drive ◽

Air Bearing ◽

Bearing Surface ◽

Head Slider ◽

Slider Air Bearing ◽

Lubricant Migration

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Optimization of Air Bearing Contours for Shock Performance of a Hard Disk Drive

Magnetic Storage Symposium: Frontiers of Magnetic Hard Disk Drive Tribology and Technology ◽

10.1115/2003-trib-342 ◽

2003 ◽

Cited By ~ 1

Author(s):

Eric M. Jayson ◽

Frank E. Talke

Keyword(s):

Hard Disk Drive ◽

Hard Disk Drives ◽

Hard Disk ◽

Disk Drive ◽

Element Model ◽

Time Dependent ◽

Air Bearing ◽

Disk Interface ◽

Shock Response ◽

Shock Event

Hard disk drives must be designed to withstand shock during operation. Large movements of the slider during shock impulse can cause reading and writing errors, track misregistration, or in extreme cases, damage to the magnetic material and loss of data. The design of the air bearing contour determines the steady state flying conditions of the slider as well as dynamic flying conditions, including shock response. In this paper a finite element model of the hard disk drive mechanical components was developed to determine the time dependent forces and moments applied to the slider during a shock event. The time dependent forces and moments are applied as external loads in a solution of the dynamic Reynolds equation to determine the slider response to a shock event. The genetic algorithm was then used to optimize the air bearing contour for optimum shock response while keeping the steady flying conditions constant. The results show substantial differences in the spacing modulation of the head/disk interface after a shock as a function of the design of the air bearing contour.

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