Abstract: A method and system for determining slider-disk contact in a hard-disk drive (HDD) that has dual independent heaters for thermal fly-height control, and dual embedded contact sensors, includes dithering power to the two heaters at different frequencies. The HDD has the two contact sensors electrically connected to provide a single combined output signal in response to the dithering. The single combined output signal is analyzed to detect two signals at the two different frequencies. When either detected signal exceeds a predetermined touchdown threshold value, the values of heater power for the two heaters are recorded, indicating that that combination of heater power values corresponds to slider-disk contact.

Abstract: A system, according to one embodiment, includes: a near field transducer, a return pole, a main pole, a waveguide adjacent the near field transducer, wherein the waveguide extends away from the near field transducer along a direction perpendicular to a media facing surface, at least one cladding layer adjacent to the waveguide, an underlayer positioned behind the near field transducer with respect to the media facing surface, the underlayer extending away from the near field transducer along the direction perpendicular to the media facing surface, and a fill material at least partially surrounding the underlayer, the waveguide and the at least one cladding layer. The underlayer has a lower coefficient of thermal expansion than the fill material. Other systems, and methods are described in additional embodiments.

Abstract: Disclosed herein are write heads for data storage devices, methods for making and using such write heads, and data storage devices comprising such write heads. A write head comprises a near-field transducer (NFT), a thermal sensor, and a shield disposed between the NFT and the thermal sensor, wherein the shield comprises a magnetic or conductive material, such as, for example, Cu, Ag, Au, Al, Rh, Ti, Cr, Mo, Fe, Co, or Ni or an alloy that includes Cu, Ag, Au, Al, Rh, Ti, Cr, Mo, Fe, Co, and/or Ni. In some embodiments, the thermal sensor comprises a first lead and a second lead, and the shield is connected to the first lead but not the second lead to provide heat sinking for the shield.

Abstract: Disclosed herein are write heads for data storage devices, methods for making and using such write heads, and data storage devices comprising such write heads. A write head comprises a near-field transducer (NFT), a thermal sensor, and a shield disposed between the NFT and the thermal sensor, wherein the shield comprises a magnetic or conductive material, such as, for example, Cu, Ag, Au, Al, Rh, Ti, Cr, Mo, Fe, Co, or Ni or an alloy that includes Cu, Ag, Au, Al, Rh, Ti, Cr, Mo, Fe, Co, and/or Ni. In some embodiments, the thermal sensor comprises a first lead and a second lead, and the shield is connected to the first lead but not the second lead to provide heat sinking for the shield.

Abstract: A data storage device is disclosed comprising a head actuated over a disk, wherein the head comprises a first sensor element and a second sensor element. When configured into a first single-ended mode, a bias signal is applied to the first sensor element to generate a first single-ended output signal based on a response of the first sensor element, and when configured into a second single-ended mode, the bias signal is applied to the second sensor element to generate a second single-ended output signal based on a response of the first sensor element. When configured into a differential mode, the bias signal is concurrently applied to the first sensor element and the second sensor element to generate a differential output signal based on a response of the first sensor element and the second sensor element.

Abstract: A system, according to one embodiment, includes: a near field transducer, a return pole, a main pole, a waveguide adjacent the near field transducer, wherein the waveguide extends away from the near field transducer along a direction perpendicular to a media facing surface, at least one cladding layer adjacent to the waveguide, an underlayer positioned behind the near field transducer with respect to the media facing surface, the underlayer extending away from the near field transducer along the direction perpendicular to the media facing surface, and a fill material at least partially surrounding the underlayer, the waveguide and the at least one cladding layer. The underlayer has a lower coefficient of thermal expansion than the fill material. Other systems, and methods are described in additional embodiments.

Abstract: A system, according to one embodiment, includes: a near field transducer, a return pole, a main pole, a waveguide adjacent the near field transducer, wherein the waveguide extends away from the near field transducer along a direction perpendicular to a media facing surface, at least one cladding layer adjacent to the waveguide, an underlayer positioned behind the near field transducer with respect to the media facing surface, the underlayer extending away from the near field transducer along the direction perpendicular to the media facing surface, and a fill material at least partially surrounding the underlayer, the waveguide and the at least one cladding layer. The underlayer has a lower coefficient of thermal expansion than the fill material. Other systems, and methods are described in additional embodiments.

Abstract: A system, according to one embodiment, includes: a near field transducer, a return pole, a main pole, a waveguide adjacent the near field transducer, wherein the waveguide extends away from the near field transducer along a direction perpendicular to a media facing surface, at least one cladding layer adjacent to the waveguide, an underlayer positioned behind the near field transducer with respect to the media facing surface, the underlayer extending away from the near field transducer along the direction perpendicular to the media facing surface, and a fill material at least partially surrounding the underlayer, the waveguide and the at least one cladding layer. The underlayer has a lower coefficient of thermal expansion than the fill material.

Abstract: A procedure for detecting the presence of contamination at a head-disk interface in a heat- assisted magnetic recording (HAMR) hard disk drive involves flying a head slider over a magnetic-recording disk at a particular fly height, applying an oscillating signal to a heat source associated with a HAMR near-field transducer (NFT) that is located in the slider to dither the spacing between the NFT and the disk, and determining, based on change to a contact detection signal, that contamination has accumulated on the slider, generally, or on the NFT, specifically. Burnishing the contamination from the slider may then be performed, by bringing the slider into contact with the disk.

Abstract: Embodiments disclosed herein generally relate to contact at the disk by the recording head in a hard disk drive. In one embodiment, a direct current is applied to an element in a HAMR head. An alternating current is then applied to the element over top of the direct current to cause the HAMR head to dither. By monitoring the head signal at the dither frequency, a touchdown or contact of a NFT on a disk may be detected based upon variations in the produced signal.

Abstract: A procedure for accurately determining thermal flying height control (TFC) touchdown power associated with a head-disk interface (HDI) in a hard disk drive (HDD) involves dithering the spacing corresponding to the HDI by applying an oscillating signal. The touchdown power with the HDI dithering applied is determined and, based on that and the dithering amplitude, the touchdown power without dithering applied, as well as the back-off power, is determinable.

Abstract: Embodiments disclosed herein generally relate to contact at the disk by the recording head in a hard disk drive. In one embodiment, a direct current is applied to an element in a HAMR head. An alternating current is then applied to the element over top of the direct current to cause the HAMR head to dither. By monitoring the head signal at the dither frequency, a touchdown or contact of a NFT on a disk may be detected based upon variations in the produced signal.

Abstract: A method, apparatus, and system are provided for implementing in-situ monitoring of head overcoat burnishing and early detection of head failure in a hard disk drive (HDD). A voltage is applied across a slider-disk interface between the slider body and the disk. Realtime monitoring of electrical current flowing across the slider-disk interface is performed for determining an amount of burnishing of the slider.

Abstract: A method and apparatus for determining the wear on a hard disk drive. Specifically, determining the overcoat wear of a head and/or disk during operation. In one embodiment, the magnetic head is disposed adjacent to the disk. A slider voltage is applied between a disk having a first overcoat and a head having a second overcoat as the disk is spinning By monitoring in real time a change in both touchdown power and a change in an interfacial current at a head disk interface, an electrochemical oxidation of the first overcoat can be determined. Additionally, by changing the polarity of the slider voltage, an electrochemical oxidation of the second overcoat can be determined. Finally, by measuring a passivation current produced between the head and the disk, the precise location of a touchdown event can be determined.

Abstract: A procedure for accurately determining thermal flying height control (TFC) touchdown power associated with a head-disk interface (HDI) in a hard disk drive (HDD) involves dithering the spacing corresponding to the HDI by applying an oscillating signal. The touchdown power with the HDI dithering applied is determined and, based on that and the dithering amplitude, the touchdown power without dithering applied, as well as the back-off power, is determinable.

Abstract: A method, apparatus, and system are provided for implementing touchdown measurement using thermal and voltage actuation for hard disk drives (HDDs). The touchdown measurement uses a constant power applied to a thermal flyheight control (TFC) and an electrostatic voltage bias pulse is applied between the slider body and the disk to actuate the slider into contact with the disk.