Komag Corporation

Wd Media, LLC

Western Digital Technologies, Inc.

Shoji Suzuki

Ta-Chang Fu

Henry S Nishihira

Dan Frusescu

David Treves

David Vigdor Salamon

Jing Liu

Koji Adachi

Wen Jiang

Daryl M Shiraki

Mary Grace Shieh

Richard Shigetoshi Mori

Lulu Xiao

David A Throckmorton

Chris Brisko

Kirk B Cheng

Rony Thomas

Jayadev P Patel

Tuan H Hua

A glass sheet configured to be cut into glass substrates for magnetic recording disks is described. The glass sheet includes a first surface. For surface features of the first surface with a feature wavelength of 60 to 500 micrometers (μm), a root mean square of a surface topography of the surface features determined using a surface analysis on the first surface with incident and reflected light is given as a microwaviness. A maximum value of the microwaviness of any arbitrary region of the first surface may be between 1.2 nanometers (nm) and 2.8 nm, inclusive of 1.2 nm and 2.8 nm. After the surface analysis, the glass sheet may be cut into the glass substrates in response to determining that the maximum value of the microwaviness is in the noted range. Further, a method of fabricating glass substrates from a glass sheet is described.

Glass sheet for fabricating magnetic recording media and method of fabricating magnetic recording media

Methods and apparatus of identifying a substrate suitable for a magnetic medium of a data storage device configured for magnetic recording are described. In an aspect, the method includes determining a roll-off value, a ski-jump value, and a radial-waviness value, each associated with an outer diameter (OD) edge region of a data surface of the substrate, and determining a calculated minimum fly height between a slider of the data storage device and a data surface of the substrate in the OD edge region based on the roll-off value, the ski-jump value, and the radial-waviness value. The method further includes comparing the calculated minimum fly height and a fly height threshold, and determining whether to utilize the substrate for the magnetic medium based on the comparison of the calculated minimum fly height and the fly height threshold.

Methods and apparatus for identifying substrates suitable for magnetic recording media

A disk for a magnetic recording apparatus is described. The disk includes a first surface extending along a first plane, a second surface extending along a second plane parallel to the first plane, and a disk thickness between the first surface and the second surface, measured along a first direction substantially normal to the first surface. The disk further includes an edge surface disposed along a perimeter of the disk and between the first surface and the second surface, where the edge surface extends along a third plane substantially perpendicular to the first surface, a first chamfer disposed between the first surface and the edge surface, and a second chamfer disposed between the second surface and the edge surface. In an aspect, a length of the edge surface measured along the first direction may be between 40% and 80% of the disk thickness.

Tuned edge profile of a disk substrate for use in magnetic recording media

Techniques for determining a maximum permissible media deposition temperature for depositing one or more layers over a substrate of a heat assisted magnetic recording (HAMR) platform. In one aspect, a method includes controlling a thermomechanical analyzer to measure the mechanical expansion of a glass material versus temperature within a temperature range that is below the primary transformation temperature (Tg) of the glass material to detect a possible initial transformation that occurs within the glass material at a temperature (Tt) below the primary transformation temperature (Tg). If such an initial transformation is detected, the maximum deposition temperature is set based on the initial transformation temperature (Tt), rather than on the primary transformation temperature (Tg). Otherwise, the maximum permissible media deposition temperature is set based on the transformation temperature (Tg). In other aspects, methods for characterizing a glass material for suitability within the substrate of the HAMR platform are provided.

Glass substrates for heat assisted magnetic recording (HAMR) and methods and apparatus for use with the glass substrates

Aspects of the disclosure provide for mitigating a coefficient of thermal expansion (CTE) mismatch between glass components and adjacent metal components in a disk storage device to improve thermal and shock performance. The methods and apparatus provide a hub, provide a first recording disk comprising a glass material and a center hole on the hub such that the hub extends through the center hole of the first recording disk, provide a first spacer on the first recording disk, the first spacer comprising a nickel-iron alloy, and provide a second recording disk comprising a glass material and a center hole on the first spacer such that the hub extends through the center hole of the second recording disk, wherein the first recording disk and the second recording disk each comprise a magnetic recording layer configured to store information.

Data storage device with composite spacer for disk stack assembly

Methods for improving the strength of glass substrates are described. One such method for strengthening a glass disk substrate for a storage device includes immersing at least a portion of the glass substrate in a solution, the solution including a solvent and a coating material selected from the group consisting of NaOH, KOH, and KNO, removing the glass substrate from the solution, allowing the solvent to evaporate from the glass substrate, and heating the glass substrate at a preselected temperature for a preselected duration, where the preselected temperature is sufficient to substantially melt the coating material and is less than a transition temperature of the glass substrate.

Methods for improving the strength of glass substrates

A method for forming a glass substrate comprises the steps of forming a glass blank with opposing substantially planar surfaces and at least one edge, coating the glass blank in silica-alumina nanoparticles, the silica-alumina nanoparticles comprising an inner core of silica with an outer shell of alumina, annealing the coated glass blank to form a conformal coating of silica-alumina around the glass blank, and polishing the coated glass blank to remove the conformal coating of silica-alumina from the opposing substantially planar surfaces thereof.

Glass substrates and methods of annealing the same

Aspects of embodiments of the present invention are directed toward a method of stacking disk-shaped substrates for polishing without using a centering shaft and an apparatus for implementing the method. A stack of disk-shaped substrates can be concentrically aligned without contacting the inside circumferential surfaces of the disk-shaped substrates by applying pressure to the outside edges of the disk-shaped substrates in different lateral directions.

Disk stacking method and apparatus

A disk drive having a magnetic recording disk with a transition zone is described. A surface texture of the transition zone induces the head to fly at a greater height than when operating over a data zone, while transitioning the head to a landing zone to park.

Magnetic recording disk having a transition zone

A disk drive with DTR media and method of assembly is described. The method may include aligning a discrete track recording (DTR) track pattern center on a DTR disk with a rotational center of a spindle hub and mounting the DTR disk on the spindle hub to minimize eccentricity. After the DTR disk is mounted to the spindle hub, it may be rotated to a designed rotational speed and the mass imbalance of the rotating DTR disk/spindle hub may be measured. The mass imbalance may be mitigated using a mechanical component such as a counter weight coupled to a spindle rotatable component, for example, the spindle hub, a spacer assembly, a clamp assembly, etc. The method may mitigate the eccentricity associated with DTR media and minimize run-out due to the mass imbalance of an otherwise rotated DTR disk/hub aligned for eccentricity correction.

Method of mitigating eccentricity in a disk drive with DTR media

A magnetic recording disk having a non laser zone texturing (LZT) band in the contact-start-stop (CSS) zone. The width of the non-LZT band in the CSS zone may be greater than the width of a read and/or write element of a head and less than the width of a center pad on the head in order to prevent contact between the read and/or write element and the CSS zone's textured surface. The width of the non-LZT band may also be designed to account for head skew angle and positioning error due to movement of a suspension arm supporting the head.

Banded LZT CSS zone

A slider having a protrusion extending beyond an air bearing surface of the slider to maintain the slider with a positive pitch angle during contact with the surface of a disk. The protrusion may be disposed on a leading edge step of the slider body with the protrusion extending beyond the air bearing surface. The slider may be used in a load/unload disk drive system to provide a positive pitch attitude to the slider at all times during operations of the disk drive system.

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San Jose, CA, United States of America

Shoji Suzuki