Abstract: An apparatus comprises a laser diode configured to generate light during a write operation. A slider comprises a near-field transducer (NFT) and an optical waveguide. The slider is configured for heat-assisted magnetic recording and to communicate the light to the NFT via the waveguide. A writer heater of the slider is configured to receive power during the write operation. A thermal sensor is situated at or near an air bearing surface of the slider. The thermal sensor is configured to produce a sensor signal in response to sensing back-heating from the medium while the NFT generates heat during a write operation. Circuitry, coupled to the thermal sensor, is configured to compare the sensor signal to a threshold and generate an output signal indicative of degradation of NFT performance in response to the sensor signal exceeding the threshold.

Abstract: An apparatus comprises a light source configured to generate light, and a modulator coupled to the light source and configured to modulate the light above a predetermined frequency. A slider is configured for heat-assisted magnetic recording and to receive the modulated light. A resistive sensor is integral to the slider and subject to heating by absorption of electromagnetic radiation and conduction of heat. Measuring circuitry is coupled to the resistive sensor and configured to measure a response of the resistive sensor due to absorbed electromagnetic radiation and not from the heat conduction. The measuring circuitry may further be configured to determine output optical power of the light source using the measured resistive sensor response.

Abstract: An apparatus comprises a laser diode configured to generate modulated light during a write operation in response to receiving modulated current having a mean amplitude that varies or is constant. A slider is configured for heat-assisted magnetic recording and to receive the modulated light. A writer heater of the slider is configured to receive power during the write operation having a magnitude that varies or is constant. A sensor is situated on or within the slider. The sensor is configured to produce a sensor signal representative of output optical power of the laser diode. Measuring circuitry is coupled to the sensor and configured to measure a change in the sensor signal indicative of a laser mode hop during the write operation.

Abstract: An apparatus comprises a light source configured to generate light, and a modulator coupled to the light source and configured to modulate the light above a predetermined frequency. A slider is configured for heat-assisted magnetic recording and to receive the modulated light. A resistive sensor is integral to the slider and subject to heating by absorption of electromagnetic radiation and conduction of heat. Measuring circuitry is coupled to the resistive sensor and configured to measure a response of the resistive sensor due to absorbed electromagnetic radiation and not from the heat conduction. The measuring circuitry may further be configured to determine output optical power of the light source using the measured resistive sensor response.

Abstract: An apparatus comprises a laser diode configured to generate light during a write operation. A slider comprises a near-field transducer (NFT) and an optical waveguide. The slider is configured for heat-assisted magnetic recording and to communicate the light to the NFT via the waveguide. A writer heater of the slider is configured to receive power during the write operation. A thermal sensor is situated at or near an air bearing surface of the slider. The thermal sensor is configured to produce a sensor signal in response to sensing back-heating from the medium while the NFT generates heat during a write operation. Circuitry, coupled to the thermal sensor, is configured to compare the sensor signal to a threshold and generate an output signal indicative of degradation of NFT performance in response to the sensor signal exceeding the threshold.

Abstract: An apparatus comprises a light source configured to generate light, and a modulator coupled to the light source and configured to modulate the light above a predetermined frequency. A slider is configured for heat-assisted magnetic recording and to receive the modulated light. A resistive sensor is integral to the slider and subject to heating by absorption of electromagnetic radiation and conduction of heat. Measuring circuitry is coupled to the resistive sensor and configured to measure a response of the resistive sensor due to absorbed electromagnetic radiation and not from the heat conduction. The measuring circuitry may further be configured to determine output optical power of the light source using the measured resistive sensor response.

Abstract: Data is written to data sectors of a heat-assisted magnetic recording (HAMR) medium using a laser of a HAMR head supplied with a sum of an operational current and a threshold current. A service current is supplied to the laser when the head is over servo sectors of the medium, such that a temperature of the medium at the servo sectors is greater than or equal to a temperature of the head when over the servo sectors.

Abstract: An apparatus comprises a laser diode configured to generate light during a write operation. A slider comprises a near-field transducer (NFT) and an optical waveguide. The slider is configured for heat-assisted magnetic recording and to communicate the light to the NFT via the waveguide. A writer heater of the slider is configured to receive power during the write operation. A thermal sensor is situated at or near an air bearing surface of the slider. The thermal sensor is configured to produce a sensor signal in response to sensing back-heating from the medium while the NFT generates heat during a write operation. Circuitry, coupled to the thermal sensor, is configured to compare the sensor signal to a threshold and generate an output signal indicative of degradation of NFT performance in response to the sensor signal exceeding the threshold.

Abstract: An apparatus comprises a laser diode configured to generate light during a write operation. A slider comprises a near-field transducer (NFT) and an optical waveguide. The slider is configured for heat-assisted magnetic recording and to communicate the light to the NFT via the waveguide. A writer heater of the slider is configured to receive power during the write operation. A thermal sensor is situated at or near an air bearing surface of the slider. The thermal sensor is configured to produce a sensor signal in response to sensing back-heating from the medium while the NFT generates heat during a write operation. Circuitry, coupled to the thermal sensor, is configured to compare the sensor signal to a threshold and generate an output signal indicative of degradation of NFT performance in response to the sensor signal exceeding the threshold.

Abstract: 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.

Abstract: A slider having an air bearing surface is configured for heat-assisted magnetic recording. A writer of the slider comprises a writer coil. A current source is configured to supply a modulated writer current at a first predetermined frequency to the writer coil. A writer heater is situated proximate the writer and configured to thermally actuate a writer region of the air bearing surface. A contact sensor is situated proximate the writer coil and configured to sense temperature changes indicative of changes in spacing and contact between the slider and a magnetic recording medium. A signal produced by the contact sensor oscillates at the first predetermined frequency. A detector is coupled to the contact sensor. The detector is configured to detect contact between the thermally actuated writer region and the medium using the contact sensor signal.

Abstract: An apparatus comprises a light source configured to generate light, and a modulator coupled to the light source and configured to modulate the light above a predetermined frequency. A slider is configured for heat-assisted magnetic recording and to receive the modulated light. A resistive sensor is integral to the slider and subject to heating by absorption of electromagnetic radiation and conduction of heat. Measuring circuitry is coupled to the resistive sensor and configured to measure a response of the resistive sensor due to absorbed electromagnetic radiation and not from the heat conduction. The measuring circuitry may further be configured to determine output optical power of the light source using the measured resistive sensor response.

Abstract: A heat generating component of a slider is energized at a predetermined frequency. The heat generating component changes a spacing between a medium and the slider. A temperature response proximate a media-facing surface of the slider is measured while the heating element is energized. Based on the measured temperature response, a determination is made as to whether the media-facing surface is contaminated. In response to determining that the media-facing surface is contaminated, remedial action is taken.

Abstract: An apparatus includes a light source, a slider including a sensor having a resistance or voltage that varies with the temperature of the sensor, the sensor being mounted to be heated by a portion of light emitted by the light source, and a controller controlling the light source power in response to the resistance or voltage of the sensor.

Abstract: A transducer comprises a slider and a laser arrangement. The laser arrangement is configured to heat a region of a magnetic medium in proximity to the slider and produce modulated laser light to cause heat-induced modulation of the slider. The laser arrangement is configured to couple laser light at a power that reduces a coercivity of magnetic material at the region for writing data to or erasing data at the region, and couple modulated laser light to cause heat-induced modulation of the slider at a power lower than the power for writing data to or erasing data at the magnetic medium.

Abstract: An apparatus is arranged to detect contact between an air bearing surface of a transducer and a medium using a modulated thermal sensor signal. A laser source produces modulated laser light. A thermal sensor is disposed at or near the air bearing surface and is subject to cyclic heating by the modulated laser light. The thermal sensor is configured to produce the modulated sensor signal in response to the cyclic heating.

Abstract: An apparatus includes a writer, an arrangement comprising a plasmonic near-field transducer (NFT) adjacent the writer and comprising a material having a temperature coefficient of resistance (TCR), and a lead arrangement connected to the NFT arrangement. In some configurations, the NFT arrangement includes a heat sink, and the lead arrangement is connected to the heat sink. In other configurations, the lead arrangement is connected directly to the NFT.

Abstract: An apparatus includes a writer, an arrangement comprising a plasmonic near-field transducer (NFT) adjacent the writer and comprising a material having a temperature coefficient of resistance (TCR), and a lead arrangement connected to the NFT arrangement. In some configurations, the NFT arrangement includes a heat sink, and the lead arrangement is connected to the heat sink. In other configurations, the lead arrangement is connected directly to the NFT.

Abstract: An apparatus includes a writer, an arrangement comprising a plasmonic near-field transducer (NFT) adjacent the writer and comprising a material having a temperature coefficient of resistance (TCR), and a lead arrangement connected to the NFT arrangement. In some configurations, the NFT arrangement includes a heat sink, and the lead arrangement is connected to the heat sink. In other configurations, the lead arrangement is connected directly to the NFT.

Abstract: A magnetic data storage medium may include a substrate, a magnetic recording layer, a protective carbon overcoat, and a monolayer covalently bound to carbon atoms adjacent a surface of the protective carbon overcoat. According to this aspect of the disclosure, the monolayer comprises at least one of hydrogen, fluorine, nitrogen, oxygen, and a fluoro-organic molecule. In some embodiments, a surface of a read and recording head may also include a monolayer covalently bound to carbon atoms of a protective carbon overcoat.