Western Digital Technologies, Inc.

Hgst Netherlands, B.v.

Sukumar Rajauria

Erhard Theodor Schreck

Robert Lee Smith

Qing Dai

Yuichi Aoki

Mehdi Habibollahzadeh

Kosuke Nagase

John Thomas Contreras

Joey Martin Poss

Pierre-Olivier Jubert

Robert Smith

Dongying Li

Yukio Kato

Kiyoshi Hashimoto

Oscar Jaime Ruiz

Rehan Ahmed Zakai

Xiaokun L Chew

Sripathi Vangipuram Canchi

Tan Duy Trinh

Jimmy Zhang

Barry C Stipe

Takuya Matsumoto

Bruno Jean Marchon

Weldon Mark Hanson

Qinghua Zeng

Shaomin Xiong

Phillip Scott Haralson

Xinzhi Xing

Masaru Furukawa

Harold H Gee

Krisda Siangchaew

Jung-Seo Park

Na Wang

Nattaporn Khamnualthong

James William Reiner

Ruihua Li

Sudha Narayan

Richard M Brockie

Wan Kuang

Farzad Novin

Yeoungchin Yoon

Yixiang Zhang

Taiebeh Tahmasebi

Huaming Xu

A data storage device may include an enclosure and a metal organic framework (MOF) container situated within an enclosure interior. The MOF container contains a MOF configured to store captive molecular units and to release the captive molecular units in gaseous form into the enclosure interior. A method of manufacturing the data storage device may include charging the MOF, attaching the MOF container to the enclosure interior, and sealing the enclosure after attaching the MOF container to the interior of the enclosure. A method of adjusting an amount of gas in a sealed data storage device may comprise including a MOF container within an interior of the sealed data storage device, the MOF container containing a MOF, charging the MOF, and, after the sealed data storage device has been placed into service, the MOF releasing captive molecular units into the interior of the sealed data storage device.

Devices and methods for metal organic framework (MOF) based oxygen replenishment in data storage devices

A Data Storage Device (DSD) includes a disk and a slider. A change in distance between the slider and the disk is determined by applying a first voltage to the slider that increases an electrostatic force between the slider and the disk. The change in distance is approximately the same across a surface of the slider facing the disk. A first power supplied to the heating element is determined that causes thermal expansion of a portion of the slider until making disk contact without applying the first voltage. A second power supplied to the heating element is determined that causes a reduced thermal expansion of the portion until making disk contact while applying the first voltage. A first power setting is calibrated based on a correlation between the determined change in distance and a difference between the first and second powers.

Thermal fly height calibration for data storage device

A data storage device may include a container comprising a gas-permeable membrane and a temperature-sensitive gas-releasing substance inside of the container. The temperature-sensitive gas-releasing substance is characterized by a gas-release profile wherein, below a critical temperature, the temperature-sensitive gas-releasing substance releases essentially none of a particular gas, and above the critical temperature, and within a range of expected operating temperatures of the data storage device, the temperature-sensitive gas-releasing substance releases the particular gas in quantities that generally increase with increasing temperature.

Passive and active gas compensation techniques for data storage devices

A heat-assisted magnetic recording apparatus may include a slider body, a submount, a laser diode assembly, and a first heat sink. The laser diode assembly comprises a plurality of lateral surfaces and a waveguide-facing surface. The submount is attached to the slider body by a first connector material. A first lateral surface of the laser diode assembly is in contact with the submount, and a second lateral surface of the laser diode assembly is in contact with the first heat sink. The first heat sink is in contact with a second connector material, which is in contact with the slider body to provide a heat flow path from the laser diode assembly to the slider body.

Reducing laser diode temperature swings in heat-assisted magnetic recording (HAMR) using a slider-mounted heat sink

Various illustrative aspects are directed to a data storage device comprising one or more disks; one or more heads, including a first head having a first laser diode and a near field transducer; and one or more processing devices configured to: preheat the first LD to a steady state temperature; write a first and a second series of writings at a plurality of thermal fly-height control powers, wherein the first and the second series of writings are written at the steady state temperature, and the first series of writings are of a shorter duration than the second series of writings; determine, for the first head, an NFT protrusion measurement based at least on a difference in TFC power used between (1) one of the first of writings and (2) one of the second series of writings, at a corresponding written signal amplitude.

Measuring NFT protrusion in a heat assisted magnetic recording drive using burst writing and a constant laser diode temperature

A data storage device may include a disk, an actuator arm assembly comprising a magnetic recording head, a laser diode, and one or more processing devices configured to: initiate a write operation, wherein the write operation is associated with a first temperature of the laser diode; measure a resistance of the laser diode, wherein the resistance corresponds to a temperature of the laser diode; detect, based at least in part on measuring the resistance, a change in the temperature of the laser diode relative to the first temperature; and in response to detecting the change, adjust the temperature of the laser diode during the write operation.

Measuring laser diode temperature and predicting mode hops using laser diode resistance

A data storage device includes a laser diode that heats an area of a disk near the read/write head. To mitigate mode hopping, the laser diode is preheated using the laser diode itself, such as by applying a reverse bias to the laser diode, during an interruption in writing of data to the disk. The laser diode is preheated to a temperature that maintains operation of the laser diode within a middle portion of a preselected gain mode and away from abrupt shifts in gain modes.

Temperature control of a laser diode by applying reverse bias in a data storage device configured for heat-assisted magnetic recording

A data storage device may include a media comprising a magnetic recording layer and a heat-assisted magnetic recording (HAMR) head for writing to the magnetic recording layer, the HAMR head comprising: a waveguide, a main pole comprising a main-pole surface facing the magnetic recording layer, a near-field transducer (NFT) situated between the main pole and the waveguide, and a transparent overcoat. The NFT comprises a main body and a micropillar. The micropillar comprises a micropillar surface facing the magnetic recording layer. A first distance between the micropillar surface and the media is less than a second distance between the main-pole surface and the media. The transparent overcoat is situated on the main-pole surface and the micropillar surface.

Near-field transducer (NFT) designs for improved performance of heat-assisted magnetic recording (HAMR)

A data storage device may include one or more disks, an actuator arm assembly comprising one or more magnetic recording heads, a laser diode positioned inside a laser diode cavity, and one or more processing devices configured to initiate a write operation, wherein initiating the write operation comprises activating a magnetic recording head corresponding to the laser diode, and applying a forward bias to the laser diode; apply a first reverse bias to the laser diode during at least one intervening event; and transition from applying the first reverse bias to the at least one laser diode to applying the forward bias to the at least one laser diode.

Managing laser diode cavity thermal transients in HAMR disk drives

Methods, data storage devices, and computer-readable media for setting the flying height of a recording head are disclosed. A method may set a value of a control parameter of the recording head to force a predetermined location of the recording head to be a touchdown location. The method may involve incrementally moving the recording head toward a surface of a recording media, and, using a temperature sensor of the recording head, detecting an onset of touchdown at the touchdown location as the recording head is incrementally moving toward the surface of the recording media. The method may set the fly-height control power by backing off from an initial fly-height control power value, which may be a sum of a power level at which the onset of touchdown at the touchdown location was detected and a power corresponding to the value of the control parameter.

Touchdown detection and write-spacing setting in magnetic recording heads with protruding features

Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position a selected head among one or more heads proximate to a corresponding disk surface among the one or more disks, wherein the selected head comprises a magnetic write element and a laser generating component; and one or more processing devices. The one or more processing devices are configured to measure a magnetic saturation responsiveness of the corresponding disk surface to heat-assisted write operations using a range of values of write laser current applied to the laser generating component. The one or more processing devices are further configured to calibrate a nominal write laser current of the selected head for the corresponding disk surface based on the measured magnetic saturation responsiveness of the corresponding disk surface.

Data storage device with laser write bias optimization using disk thermal-magnetic response mapping in heat-assisted magnetic recording

A HAMR data storage device may include a magnetic media and a slider comprising: a main pole, a waveguide, and a near-field transducer (NFT) situated between the main pole and the waveguide, wherein an air-bearing surface (ABS) of the slider comprises a transparent overcoat layer situated over the main pole, the waveguide, and the NFT, and wherein the transparent overcoat layer has a particular thickness such that, during an operational phase of the HAMR data storage device, a gap between a media-facing surface of the transparent overcoat layer and the magnetic media is less than about 0.5 nm.

Local extension of head overcoat with a near-field transducer extending toward the media-facing surface

A data storage device may include one or more disks, an actuator arm assembly comprising one or more disk heads, at least one laser diode positioned inside a corresponding laser diode cavity, a preamplifier, and one or more processing devices. The one or more processing devices are configured to: generate a reverse bias; apply, using the preamplifier, the reverse bias to the at least one laser diode to preheat a corresponding laser diode cavity to a target temperature prior to a write operation; control transition of the preamplifier from applying the reverse bias to applying a forward bias to the at least one laser diode; and activate the at least one laser diode to begin the write operation.

Preheating laser diodes with reverse bias for HAMR disk drives

Various illustrative aspects are directed to a data storage device comprising a disk; a read/write head configured to read data from and write data to the disk; a laser diode configured to heat an area of the disk near the read/write head; and one or more processing devices configured to preheat the laser diode to a target temperature associated with a write operation, wherein the preheating comprises applying (e.g., using a preamplifier) at least one forward bias pulse to the laser diode, wherein a corresponding duration of the at least one forward bias pulse is shorter than a duration of a turn-on delay for the laser diode; and initiate a write operation for writing data to the disk, based at least in part on the preheating.

Dark laser heating by positive pulse biasing in heat assisted magnetic recording

The present disclosure generally relates to a multi-disk drive comprising a plurality of media surfaces and a plurality of heads, wherein a head of the plurality of heads is configured to be actuated over each surface of the plurality of media surfaces. The multi-disk drive further comprises control circuitry configured to write data to a first media surface of the plurality of media surfaces using a first head of the plurality of heads, and after all of an available memory of the first media surface has been filled, write data to a second media surface of the plurality of media surfaces using a second head of the plurality of heads. The control circuitry is further configured to permanently disable write access to one or more media surfaces of the plurality of media surfaces, while continuing to permit read access to the plurality of media surfaces.

Full disk serpentine write path for tamper-proof disk drive

Growing community of inventors

San Jose, CA, United States of America

Sukumar Rajauria