Seagate Technology Incorporated

Saegate Technology LLC

Huazhou Lou

Jason Wayne Riddering

Dongming Liu

Declan Macken

Timothy William Stoebe

Lin Zhou

James Gary Wessel

Michael Thomas Johnson

Xuan Zheng

Zine-Eddine Boutaghou

Edward Charles Gage

Yuhang Cheng

Gary Joseph Kunkel

Dipeshkumar J Purani

Kevin Richard Heim

Robert Dean Turner

Martin Liam McGarry

Shawn Stephen Silewski

Vincent Engelkes

Eric John McCalla

Peter W Kanas

Shaikh Mubassar Ali

Alfredo Sam Chu

Drew Michael Mader

Richard Edward Martin

Peter Kevin McGeehin

Pu-Ling Lu

Yimin Niu

Deborah S Schnur

Bruno Jacques Marchon

Juil Lee

James Robert Oscarson

Tae Young Kim

Peter Kevin McGeenhin

Michael P DeFeo

Described are hard disk drives that include a low density atmosphere, with which is included a passivating gas, and methods of using these hard disk drives and methods of assembling these hard disk drives.

Hard disk drive with low density atmosphere

A heat-assisted magnetic recording device is disposed in a hermetically sealed enclosure. The device includes a slider comprising a reader, a writer, and an optical waveguide configured to couple light from a light source to a near-field transducer situated at or near an air bearing surface of the slider. The near-field transducer comprises an enlarged portion and a peg extending from the enlarged portion in a direction of the air bearing surface. A fill gas is provided within the enclosure. The fill gas comprises a mixture of a low-density, inert gas and at least one gas that oxidizes carbon, where the total carbon oxidizing gas concentration of the fill gas is 3-50% by volume. In certain embodiments, the fill gas comprises a hydrogen concentration sufficient to retard oxidation of the peg when the peg is at an operating temperature associated with write operations.

Oxidizing or reducing atmosphere for heat-assisted magnetic recording

A data storage drive includes a rotatable data storage medium, and a head communicatively couplable to the data storage medium. The head includes a temperature sensor and a heater. The data storage drive also includes a ramp for supporting the head when the head is moved away from the data storage medium, and a controller. The controller is configured to obtain first temperature sensor measurement values for different head heater power settings when the head is positioned on the ramp, and is configured to determine an internal pressure of the data storage drive as a function of the first temperature sensor measurement values.

Data storage drive pressure sensing using a head temperature sensor and a head heater

An apparatus comprises a slider configured for writing data to and reading data from a magnetic recording medium and for heat-assisted magnetic recording. The slider comprises a heater configured to receive an AC signal and to cause oscillation in a spacing between the slider and the medium, and a contact sensor situated on the slider and configured to produce a DC response signal. A detector is coupled to the slider and configured to measure an amplitude of a spike in the DC response signal, calculate a ratio between the spike amplitude and an amplitude of the DC response signal, and detect contact between the slider and the medium in response to the ratio exceeding a predetermined threshold.

Head-disk contact detection using a thermal sensor for modulation air bearings

A lumped-parameter function &#x3b4; is determined that represents an average power dissipated by a write transducer when writing a signal to a magnetic recording medium. Temperatures of the write transducer are measured while varying the parameters to determine constants of the function &#x3b4;. The function &#x3b4; is used to adjust power applied to a clearance control heater when writing to the magnetic recording medium.

Lumped-parameter thermal model of a write transducer for clearance control on magnetic recording device

A change in servo active gain control values is determined from a beginning of a writing of a test region of a recording medium to an end of the writing of the test region. The servo active gain control values are read from servo marks by a read transducer of a read/write head during the writing. After writing of the test region, the test region is read by the read transducer to determine a change in recorded amplitude from the beginning of the writing to the end of the writing. A gamma value of the read/write head is determined based on the change in servo active gain control values and the change in recorded amplitude.

Determining gamma of a read/write head based on active gain control and test signal amplitude measurements

Using a high sample rate dPES, together with pulsed heater and lock-in technique, to improve dPES SNR for contact detection between the head and media surface. Steps of powering a transducing head actuator with pulsed input signal at a select data track offset from a previously-written to data track of the storage medium, where the pulsed input signal has select amplitude and duty cycle to simulate a response signal, and further locking in an amplitude with respect to the heater frequency, can lead to a determination of level of heater power for initiating contact between the transducing head and the storage medium.

High sample rate dPES to improve contact detection signal to noise ratio

A heat-assisted magnetic recording (HAMR) head includes a reader, a writer, a writer heater, a laser, and a near-field transducer (NFT). A processor is coupled to the head and configured to perform laser writeability calibration of the head. The processor is also configured to concurrently while performing the laser writeability calibration, correct for laser induced writer protrusion (LIWP) at a writer/NFT region of the head using writer clearance calculations based on reader clearance measurements.

Concurrent laser induced writer protrusion correction and laser writeability calibration

A test involves iterations over a series of laser powers of a heat-assisted read/write head. The iterations involve writing to a recording medium at the selected laser power for a sufficient duration to ensure thermal equilibrium of the read/write head at an end of the write. A clearance-control heater of the read/write head is transitioned from a pre-write power before a start of the write to a steady-state write power. The iterations further involve measuring a temperature of the read/write head during the write and adjusting the steady-state write power to achieve a predefined difference between the temperature at the start of the write and the end of the write. The adjusted steady state write power is stored for each iteration. A write-induced protrusion is determined based on the iterations and used for calibration of the read/write head.

Determining write-induced protrusion as a function of laser power using temperature measurements

Method and apparatus for controlling the fly height of a transducer. In some embodiments, a data pattern is written to a rotating data recording surface using a transducer having a write element, a read element and a thermal assist energy source. A first protrusion distance for the read element induced by operation of the energy source is determined responsive to first and second readback amplitudes obtained from the data pattern using different first and second power levels applied to the energy source. A second protrusion distance for the write element induced by the energy source is determined responsive to the first protrusion distance.

Thermally assisted writer protrusion determination and control

An apparatus comprises a heat-assisted magnetic recording (HAMR) head, a sensor, and a controller. The HAMR head is configured to interact with a magnetic storage medium. The sensor is configured to produce a signal indicating the occurrence of head-medium contact. The controller is configured to receive the signal and concurrently determine from the signal if the occurrence of head-medium contact is caused by a first contact detection parameter, a second contact detection parameter, or both the first and second contact detection parameters.

Concurrent modulation and frictional heating head disk contact detection

A magnetic recording head comprises a transducer, a heater, a writer and a laser. The transducer is configured to write to a magnetic recording medium during a write operation. The heater, writer and laser are configured to affect a protrusion of the transducer. The heater is calibrated to produce a pre-write heater power to obtain a target pre-write clearance for a write operation through use of a clearance-heater power curve. The curve is generated by measuring a clearance between the transducer and the medium as the heater is cycled from zero to a contact power.

Heat-assisted magnetic recording head-disk clearance setting

A head transducer, configured to interact with a magnetic recording medium, includes a first sensor having a temperature coefficient of resistance (TCR) and configured to produce a first sensor signal, and a second sensor having a TCR and configured to produce a second sensor signal. One of the first and second sensors is situated at or near a close point of the head transducer in relation to the magnetic recording medium, and the other of the first and second sensors spaced away from the close point. Circuitry is configured to combine the first and second sensor signals and produce a combined sensor signal indicative of one or both of a change in head-medium spacing and head-medium contact. Each of the sensors may have a TCR with the same sign (positive or negative) or each sensor may have a TCR with a different sign.

Head transducer with multiple resistance temperature sensors for head-medium spacing and contact detection

A method includes setting a heat assisted magnetic recording (HAMR) device located in a data storage system having a laser to an operating temperature. A threshold laser current is determined. An optimal laser current is determined. The threshold laser current and the optimal laser current are stored in memory. The steps of determining a threshold laser current, determining an optimal laser current and storing the threshold laser current and the optimal laser current into the calibration table are repeated until acceptable device performance is achieved at more than one operating temperature.

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Eden Prairie, MN, United States of America

Huazhou Lou