Abstract: A data storage device includes a laser diode that heats an area of a disk near the read/write head. To mitigate mode hopping, the laser diode is preheated using the laser diode itself, such as by applying a reverse bias to the laser diode, during an interruption in writing of data to the disk. The laser diode is preheated to a temperature that maintains operation of the laser diode within a middle portion of a preselected gain mode and away from abrupt shifts in gain modes.

Abstract: A data storage device may include a media comprising a magnetic recording layer and a heat-assisted magnetic recording (HAMR) head for writing to the magnetic recording layer, the HAMR head comprising: a waveguide, a main pole comprising a main-pole surface facing the magnetic recording layer, a near-field transducer (NFT) situated between the main pole and the waveguide, and a transparent overcoat. The NFT comprises a main body and a micropillar. The micropillar comprises a micropillar surface facing the magnetic recording layer. A first distance between the micropillar surface and the media is less than a second distance between the main-pole surface and the media. The transparent overcoat is situated on the main-pole surface and the micropillar surface.

Abstract: A data storage device may include one or more disks, an actuator arm assembly comprising one or more magnetic recording heads, at least one laser diode, and one or more processing devices configured to: set the at least one laser diode to a first temperature; apply a first forward bias and supply a first current to the at least one laser diode such that it is in a lasing state; measure, for the at least one laser diode, a first output corresponding to the first temperature and current; set the at least one laser diode to a second temperature; measure, for the at least one laser diode, a second output corresponding to the second temperature and the first current; and determine an output profile for the at least one laser diode, based at least in part on the respective output at the first temperature and the second temperature.

Abstract: A data storage device may include a disk, an actuator arm assembly comprising a magnetic recording head, a laser diode, and one or more processing devices configured to: initiate a write operation, wherein the write operation is associated with a first temperature of the laser diode; measure a resistance of the laser diode, wherein the resistance corresponds to a temperature of the laser diode; detect, based at least in part on measuring the resistance, a change in the temperature of the laser diode relative to the first temperature; and in response to detecting the change, adjust the temperature of the laser diode during the write operation.

Abstract: A data storage device may include one or more disks, an actuator arm assembly comprising one or more magnetic recording heads, a laser diode positioned inside a laser diode cavity, and one or more processing devices configured to initiate a write operation, wherein initiating the write operation comprises activating a magnetic recording head corresponding to the laser diode, and applying a forward bias to the laser diode; apply a first reverse bias to the laser diode during at least one intervening event; and transition from applying the first reverse bias to the at least one laser diode to applying the forward bias to the at least one laser diode.

Abstract: Methods, data storage devices, and computer-readable media for setting the flying height of a recording head are disclosed. A method may set a value of a control parameter of the recording head to force a predetermined location of the recording head to be a touchdown location. The method may involve incrementally moving the recording head toward a surface of a recording media, and, using a temperature sensor of the recording head, detecting an onset of touchdown at the touchdown location as the recording head is incrementally moving toward the surface of the recording media. The method may set the fly-height control power by backing off from an initial fly-height control power value, which may be a sum of a power level at which the onset of touchdown at the touchdown location was detected and a power corresponding to the value of the control parameter.

Abstract: A data storage device may include a media comprising a magnetic recording layer and a heat-assisted magnetic recording (HAMR) head for writing to the magnetic recording layer, the HAMR head comprising: a waveguide, a main pole comprising a main-pole surface facing the magnetic recording layer, a near-field transducer (NFT) situated between the main pole and the waveguide, and a transparent overcoat. The NFT comprises a main body and a micropillar. The micropillar comprises a micropillar surface facing the magnetic recording layer. A first distance between the micropillar surface and the media is less than a second distance between the main-pole surface and the media. The transparent overcoat is situated on the main-pole surface and the micropillar surface.

Abstract: A HAMR data storage device may include a magnetic media and a slider comprising: a main pole, a waveguide, and a near-field transducer (NFT) situated between the main pole and the waveguide, wherein an air-bearing surface (ABS) of the slider comprises a transparent overcoat layer situated over the main pole, the waveguide, and the NFT, and wherein the transparent overcoat layer has a particular thickness such that, during an operational phase of the HAMR data storage device, a gap between a media-facing surface of the transparent overcoat layer and the magnetic media is less than about 0.5 nm.

Abstract: A HAMR data storage device may include a magnetic media and a slider comprising: a main pole, a waveguide, and a near-field transducer (NFT) situated between the main pole and the waveguide, wherein an air-bearing surface (ABS) of the slider comprises a transparent overcoat layer situated over the main pole, the waveguide, and the NFT, and wherein the transparent overcoat layer has a particular thickness such that, during an operational phase of the HAMR data storage device, a gap between a media-facing surface of the transparent overcoat layer and the magnetic media is less than about 0.5 nm.

Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position a selected head among one or more heads proximate to a corresponding disk surface among the one or more disks, wherein the selected head comprises a magnetic write element and a laser generating component; and one or more processing devices. The one or more processing devices are configured to measure a magnetic saturation responsiveness of the corresponding disk surface to heat-assisted write operations using a range of values of write laser current applied to the laser generating component. The one or more processing devices are further configured to calibrate a nominal write laser current of the selected head for the corresponding disk surface based on the measured magnetic saturation responsiveness of the corresponding disk surface.

Abstract: A data storage device may include one or more disks, an actuator arm assembly comprising one or more disk heads, at least one laser diode positioned inside a corresponding laser diode cavity, a preamplifier, and one or more processing devices. The one or more processing devices are configured to: generate a reverse bias; apply, using the preamplifier, the reverse bias to the at least one laser diode to preheat a corresponding laser diode cavity to a target temperature prior to a write operation; control transition of the preamplifier from applying the reverse bias to applying a forward bias to the at least one laser diode; and activate the at least one laser diode to begin the write operation.

Abstract: Various illustrative aspects are directed to a data storage device comprising a disk; a read/write head configured to read data from and write data to the disk; a laser diode configured to heat an area of the disk near the read/write head; and one or more processing devices configured to preheat the laser diode to a target temperature associated with a write operation, wherein the preheating comprises applying (e.g., using a preamplifier) at least one forward bias pulse to the laser diode, wherein a corresponding duration of the at least one forward bias pulse is shorter than a duration of a turn-on delay for the laser diode; and initiate a write operation for writing data to the disk, based at least in part on the preheating.

Abstract: A data storage device may include one or more disks, an actuator arm assembly comprising one or more magnetic recording heads, a laser diode positioned inside a laser diode cavity, and one or more processing devices configured to initiate a write operation, wherein initiating the write operation comprises activating a magnetic recording head corresponding to the laser diode, and applying a forward bias to the laser diode; apply a first reverse bias to the laser diode during at least one intervening event; and transition from applying the first reverse bias to the at least one laser diode to applying the forward bias to the at least one laser diode.

Abstract: A data storage device may include one or more disks, an actuator arm assembly comprising one or more disk heads, at least one laser diode positioned inside a corresponding laser diode cavity, a preamplifier, and one or more processing devices. The one or more processing devices are configured to: generate a reverse bias; apply, using the preamplifier, the reverse bias to the at least one laser diode to preheat a corresponding laser diode cavity to a target temperature prior to a write operation; control transition of the preamplifier from applying the reverse bias to applying a forward bias to the at least one laser diode; and activate the at least one laser diode to begin the write operation.

Abstract: The present disclosure generally relates to a multi-disk drive comprising a plurality of media surfaces and a plurality of heads, wherein a head of the plurality of heads is configured to be actuated over each surface of the plurality of media surfaces. The multi-disk drive further comprises control circuitry configured to write data to a first media surface of the plurality of media surfaces using a first head of the plurality of heads, and after all of an available memory of the first media surface has been filled, write data to a second media surface of the plurality of media surfaces using a second head of the plurality of heads. The control circuitry is further configured to permanently disable write access to one or more media surfaces of the plurality of media surfaces, while continuing to permit read access to the plurality of media surfaces.

Abstract: The present disclosure relates to pretreating a magnetic recording head. For a HAMR head, a NFT is present. Current can be applied to the NFT to condition the NFT. The current is applied in one of three ways: slowly ramping up the current from a starting level below a level capable of writing data to the optical laser current over a predetermined period of time, applying the current at a fixed value below the optical laser current for the predetermined period of time, or slowly ramping up the current from a starting level below a level capable of writing data to the optical laser current over the predetermined period of time while also intermittently removing the current. By conditioning the NFT in such a manner, the HAMR head can avoid thermal shock and thermal fatigue and thus increase the lifetime of the magnetic media drive.

Abstract: The present disclosure generally relates to a multi-disk drive comprising a plurality of media surfaces and a plurality of heads, wherein a head of the plurality of heads is configured to be actuated over each surface of the plurality of media surfaces. The multi-disk drive further comprises control circuitry configured to write data to a first media surface of the plurality of media surfaces using a first head of the plurality of heads, and after all of an available memory of the first media surface has been filled, write data to a second media surface of the plurality of media surfaces using a second head of the plurality of heads. The control circuitry is further configured to permanently disable write access to one or more media surfaces of the plurality of media surfaces, while continuing to permit read access to the plurality of media surfaces.

Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; a head, configured to be positioned proximate to a disk surface among the one or more disks; a temperature sensor; and one or more processing devices. The one or more processing devices are configured to: detect, via the temperature sensor, a non-nominal heat dissipation of a portion of the head; and, in response to detecting the non-nominal heat dissipation of the portion of the head, mitigate the non-nominal heat dissipation of the portion of the head.

Abstract: Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium that has a media carbon dual-layer media carbon overcoat with both a carbon layer and a carbon-nitrogen (CN) layer. The carbon layer may be a plasma enhanced chemical vapor deposition (PECVD) carbon layer and the CN layer may be a sputtered CN layer. The dual-layer media carbon overcoat helps reduce a laser power requirement of an HAMR disk drive system and thus reduce the operating temperature of a near field transducer (NFT) of a HAMR disk drive. The dual-layer overcoat can also improve thermal and thermo-oxidative stability of the media and help retain a lubricant provided on the overcoat, therefore improving HAMR head-media interface reliability. The dual-layer media carbon overcoat can also reduce carbonaceous smear within a head-media gap.

Abstract: The present disclosure generally relates to using a data timestamp and/or a read counter to prevent data from being re-read and signal that the data has been accessed. The write assist element in the write head can be utilized to degrade the data or an allocated marker after the data has been read. The degradation functions as a read counter to indicate how many times the data has been read. Additionally and/or alternatively, a timestamp can be utilized. The timestamp is updated each time that the data has been accessed. In so doing, it is possible to determine whether data in a data storage device has been accessed.