Hgst Netherlands, B.v.

Western Digital Technologies, Inc.

Sripathi Vangipuram Canchi

Erhard Theodor Schreck

Sukumar Rajauria

Shaomin Xiong

Na Wang

Barry C Stipe

Bruno Jean Marchon

Michael Grobis

Oscar Jaime Ruiz

Lidu Huang

Ricardo Ruiz

Qing Dai

Kenji Kuroki

Remmelt Pit

Weidong Huang

Yong Hu

Robert Lee Smith

Nobuyuki Okunaga

Vipin Ayanoor-Vitikkate

Franck Rose

Hitesh Arora

James William Reiner

Saurabh Deoras

Kenji Tasaka

Yuichiro Sano

Ehsan Rismaniyazdi

Disclosed herein is a magnetic storage device that comprises a housing defining an interior cavity. The magnetic storage device also comprises at least one magnetic disk in the interior cavity of the housing. The magnetic storage device further comprises at least one read-write head in the interior cavity and configured to read data from and write data to the magnetic disk. The read-write head comprises a heat-assisted magnetic storage (HAMR) head. The magnetic storage device additionally comprises a gas, comprising oxygen and helium, sealed in the interior cavity of the housing. A percent concentration of oxygen in the gas is greater than or equal to 3%. A pressure of the gas is between 10% and 70%, inclusive, of atmospheric pressure. A relative humidity within the interior cavity is less than 5%, inclusive. A percent concentration of helium in the gas is less than or equal to 90%.

Magnetic storage device with heat-assisted magnetic storage head and associated method of manufacture

A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a fly height actuator (FHA). An FHA control signal is applied to the FHA, wherein the FHA control signal comprises a rectangular wave having a duty cycle in the range of ten percent to thirty percent. While applying the FHA control signal to the FHA, the head touching down onto the disk is detected.

Data storage device employing low duty cycle square wave to detect head touchdown

A method for magnetic data recording that calibrates for magnetic thermal protrusion of elements of a magnetic data recording system. The method involves performing a series of burst mode magnetic data writings using a magnetic recording head that includes a write element, a thermal fly height control element and a near field transducer. The burst mode writings are performed at various levels of thermal fly height control power. This can be use to determine the relationship between signal amplitude and thermal fly height control power with thermal protrusion being affected only by the thermal fly height control element and not from thermal heating of the near field transducer or write element. Then, thermal fly height control can be adjusted to achieve the desired signal amplitude for recording with the near field transducer and write element operating at a thermal steady state.

Burst writing for clearance calibration in a heat assisted magnetic data recording system

A procedure for accurately determining thermal flying height control (TFC) touchdown power associated with a head-disk interface (HDI) in a hard disk drive (HDD) involves dithering the spacing corresponding to the HDI by applying an oscillating signal. The touchdown power with the HDI dithering applied is determined and, based on that and the dithering amplitude, the touchdown power without dithering applied, as well as the back-off power, is determinable.

Hard disk drive head-disk interface dithering

A method, apparatus, and system are provided for implementing touchdown measurement using thermal and voltage actuation for hard disk drives (HDDs). The touchdown measurement uses a constant power applied to a thermal flyheight control (TFC) and an electrostatic voltage bias pulse is applied between the slider body and the disk to actuate the slider into contact with the disk.

Implementing enhanced ultrafast touchdown measurement scheme using thermal and voltage actuation for hard disk drives

A method to fabricate an imprint template for bit-patterned magnetic recording media using block copolymers (BCPs) integrates data region patterning and servo region patterning. A heat sink layer is formed on the imprint substrate only in the data regions. A sublayer for the BCP is deposited over both the data regions and the servo regions and patterned to form stripes in the data regions and servo features in the servo regions. A BCP is then deposited in both the data and servo regions. Only the BCP in the data regions is heated, which causes phase separation of the BCP in the data regions into the two BCP components. The selective heating may be accomplished by directed controlled laser radiation to only the data regions. The heat sink layer below the data regions absorbs the heat from the laser radiation, confining it to the data regions.

Method for making an imprint template with data regions and non-data regions using block copolymers

Embodiments described herein generally relate to controlling the flying height of a slider. The methods can include transmitting radiation from a radiation source, determining a change in temperature, the change in temperature being the difference between a first temperature and an ambient temperature and changing the flying height of the slider and head based on the change in temperature. The devices generally include a head with a supporting surface and a media facing surface, a radiation source submount, a radiation source, and a temperature sensor positioned proximate the radiation source submount or the radiation source.

Compensation of laser diode introduced flying height changes

Embodiments of the present invention generally relate to a method for obtaining head/disk clearance based on ECS signal. The ECS is calibrated by applying different interface voltages to cause changes in the head/disk clearance, the ECS signal at each interface voltage is obtained, and the relationship between the change in head/disk clearance and the ECS signal is calculated. From this relationship, the head/disk clearance may be obtained based on ECS signal.

Method to convert and calibrate the embedded contact sensor signal to clearance and spacing information using interface voltage control

A data storage device and method for enabling dynamic fly height control which is insensitive to off-track motions is described. In some embodiments, a hard disk drive acquires signal data from neighboring overlapping tracks which are unwritten, thermally erased, or AC demagnetized. Side-to-side (off-track) positional errors or oscillations of the read head do not affect the signal which arises solely from the magnetic domains on the disk. Thus, signal variations may only arise from changes in the fly height. In other embodiments, neighboring overlapping data tracks are prewritten with reference data. The width of the neighboring overlapping tracks exceeds any expected side-to-side positional errors of the read head, thus signal variations may only arise from changes in the fly height. For all embodiments, the noise or reference data signal may serve as a reliable dynamic measure of the fly height with no effects arising from off-track motions.

Dynamic fly height control that is insensitive to off-track motion

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San Jose, CA, United States of America

Sripathi Vangipuram Canchi