Seagate Technology Incorporated

Zhen Wei

Gary Joseph Kunkel

Brian William Karr

Manuel Charles Anaya-Dufresne

Hua Liu

Declan Macken

John Charles Duda

James Dillon Kiely

Neil Zuckerman

Peng Peng

Eric L Montei

Darreyl S Sedbrook

Muhammed Mujahid Khan

A method includes moving a heat-assisted magnetic recording (HAMR) slider relative to a magnetic recording medium. The slider comprises a writer, a writer heater, and a near-field transducer (NFT). For each of a plurality of different head-to media spacings a test tone is written to a track of the medium, the test tone is read and a Discrete Fourier Transform (DFT) of an amplitude of the read test tone is captured. A first DFT curve is generated at a beginning of writing the test tones. A second DFT curve is generated at a saturated state of writing the test tones. An amount of horizontal shift between the first and second DFT curves is computed. The amount of horizontal shift corresponding to writer heater power required to compensate for NFT clearance offset due to laser induced writer protrusion.

Calculating a heater power that compensates for laser induced writer protrusion for a heat-assisted magnetic recording device

An apparatus comprising a slider and a detector coupled to the slider. The slider is configured for writing data to and reading data from a magnetic recording medium. The slider comprises a heater configured to receive a modulated signal and cause oscillation in a spacing between the slider and the medium. At least one heat generating component of the slider is configured to receive a modulated signal. A contact sensor is situated on the slider to receive heat generated by the at least one heat generating component. The detector is configured to measure a response signal of the heated contact sensor as the slider approaches the medium. The detector is further configured to detect contact between the slider and the medium in response to the response signal reaching a predetermined threshold.

Head-medium contact detection using a thermal sensor heated by multiple heat generating components of a slider

A sensor supported by a head transducer has a temperature coefficient of resistance (TCR) and a sensor resistance. The sensor operates at a temperature above ambient and is responsive to changes in sensor-medium spacing. Conductive contacts connected to the sensor have a contact resistance and a cross-sectional area adjacent to the sensor larger than that of the sensor, such that the contact resistance is small relative to the sensor resistance and negligibly contributes to a signal generated by the sensor. A multiplicity of head transducers each support a TCR sensor and a power source can supply bias power to each sensor of each head to maintain each sensor at a fixed temperature above an ambient temperature in the presence of heat transfer changes impacting the sensors. A TCR sensor of a head transducer can include a track-oriented TCR sensor wire for sensing one or both of asperities of the medium.

Resistive temperature sensors for improved asperity, head-media spacing, and/or head-media contact detection

A first biasing potential is sent to a first input end of a first temperature coefficient of resistance (TCR) sensor having a first ground end coupled to a ground potential. A second biasing potential is sent to a second input end of a second TCR sensor having a second ground end coupled to the ground potential. The first and the second biasing potentials are changed to operate in a plurality of modes.

Flexible biasing strategy for ground-split TCR sensors

Growing community of inventors

Maple Grove, MN, United States of America

Zhen Wei