Seagate Technology Incorporated

Saegate Technology LLC

Dongming Liu

Michael Thomas Johnson

Huazhou Lou

Lin Zhou

Xuan Zheng

Declan Macken

James Gary Wessel

Timothy William Stoebe

Andrew D Habermas

Kenneth A Haapala

Scott Edward Ryun

Adam Karl Himes

Edwin F Rejda

Shanlin X Hao

Jeff O'Konski

Lee Clifford Knippenberg

Andrew Sherve

Shawn Stephen Silewski

Lance Eugene Stover

Jason Wayne Riddering

James Keith Price

Vincent Engelkes

Juil Lee

Eric John McCalla

Edward Michael Erickson

Manuel Charles Anaya Dufresne

Bruce Anderson

James Robert Oscarson

The present disclosure includes methods of lapping that include energizing one or more elements that are located proximal to a first magnetoresistive element in a transducer region and generate heat and cause the first magnetoresistive element to selectively expand in the lapping direction relative to one or more other magnetoresistive elements. The present disclosure also includes methods of lapping that use one or more thermal sensors located proximal to the first magnetoresistive element to help control lapping in the lapping direction. The present disclosure includes related lapping systems and sliders.

Methods of lapping while heating one or more features, and related sliders, row bars, and systems

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

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

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 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 and apparatus are provided for positioning a transducer relative to a track of a data storage medium and inducing lateral modulation of transducer the relative to the track. An element of the transducer is actuated toward the storage medium during the lateral modulation, and atomic interaction is detected between the element and the storage medium because of a change in a response to the lateral modulation of the transducer due to the atomic interaction.

Method and apparatus for detecting proximity contact between a transducer and a medium

A method of detecting a contact between a transducing head and a storage medium is provided. The method applies an input signal, having a select power level and known frequency, to an actuator for actuating the head. An output signal is obtained in response to the input signal. At least one signal component is extracted from the output signal at the same or a harmonic of the same known frequency as the input signal applied to the actuator. Whether the at least one extracted signal component indicates a contact between the head and the medium is determined. The power level of the applied wave pattern is increased incrementally until the extracted signal component indicates a contact between the head and the storage medium.

Contact detection

A bias signal is applied to a resistive thermal sensor located proximate a magnetic media reading surface of a magnetic sensor. The bias signal is modulated between first and second bias levels. First and second resistances of the resistive thermal sensor corresponding to the first and second bias levels are measured. Based a difference between the first and second resistances caused by in increase in thermal conductivity between the magnetic sensor and a medium as the magnetic head gets closer to the medium, at least one of a spacing and a contact between the magnetic sensor and the medium are determined.

Using first and second resistive sensor bias levels to detect head-to-disk contact and/or clearance

An apparatus includes a head transducer configured to interact with a magnetic recording medium and a heater configured to thermally actuate the head transducer. A thermal sensor at or near the head transducer is configured to produce a sensor signal. Circuitry is coupled to the heater and configured to cause an oscillation in heater power. The heater power oscillation causes an oscillation in the sensor signal. A detector is coupled to the thermal sensor and configured to detect head-medium contact using the oscillating sensor signal and heater power.

Head-medium contact detection using introduced heat oscillation

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Eden Prairie, MN, United States of America

Dongming Liu