Abstract: Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium that has a magnetic recording layer on a MgO—TiO (MTO) underlayer, where the MTO underlayer is formed using pulsed DC sputtering and has less than 50 mol % of TiO. By providing an MTO layer with less than 50 mol % of TiO, smaller grain sizes may be achieved in the magnetic recording layer, providing for higher areal densities. In some embodiments, a second MTO underlayer is provided, which is formed using non-pulsed DC sputtering and has 50 mol % of TiO. That is, a dual-layer MTO underlayer may be provided with, e.g., an MgO-30TiO layer atop an MgO-50TiO layer.

Abstract: Various apparatuses, systems, methods, and media are disclosed for heat-assisted magnetic recording (HAMR) that includes a HAMR medium with a seed-thermal barrier structure. The seed-thermal barrier structure is positioned between a heat sink layer and a magnetic recording layer. In some examples, the seed-thermal barrier structure has a first layer including MgOTiO (MTO), a second layer including TiN on the first layer, a third layer on the second layer, and a fourth layer including MTO on the third layer. The third layer, in some examples, includes at least one of: RuAl, Pt, PtZr, PtTa, Rh, FePt, CrMo, or Cr.

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: Various apparatuses, systems, methods, and media are disclosed for heat-assisted magnetic recording (HAMR) that, in some examples, provide a HAMR medium with two soft underlayers (SULs) on opposing sides of a single heatsink layer. For example, a magnetic recording medium is provided that includes a lower SUL on a substrate. The lower SUL is configured and positioned within the medium to provide a first return path for magnetic flux from a magnetic recording head during a write operation. The medium also includes a heatsink layer on the lower SUL and an upper SUL on the heatsink layer. The upper SUL is configured and positioned within the medium to provide a second return path for magnetic flux from the magnetic recording head. A magnetic recording layer is provided on the upper SUL to store information during the write operation. Additional layers or films may be provided as well.

Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to a corresponding disk surface of the one or more disks; and one or more processing devices. The one or more processing devices are configured to generate a determination of magnetic responsiveness to thermal energy of at least one position of the corresponding disk surface in response to an operation of the selected head. The one or more processing devices are further configured to determine and apply a pre-bias current to the thermally energizing component prior to a write operation, with the selected head proximate to the at least one position of the corresponding disk surface, wherein the pre-bias current is based on the determination of magnetic responsiveness to thermal energy of the at least one position of the corresponding disk surface.

Abstract: Various apparatuses, systems, methods, and media are disclosed for heat-assisted magnetic recording (HAMR) that, in some examples, provide a HAMR medium with two soft underlayers (SULs) on opposing sides of a single heatsink layer. For example, a magnetic recording medium is provided that includes a lower SUL on a substrate. The lower SUL is configured and positioned within the medium to provide a first return path for magnetic flux from a magnetic recording head during a write operation. The medium also includes a heatsink layer on the lower SUL and an upper SUL on the heatsink layer. The upper SUL is configured and positioned within the medium to provide a second return path for magnetic flux from the magnetic recording head. A magnetic recording layer is provided on the upper SUL to store information during the write operation. Additional layers or films may be provided as well.

Abstract: Various apparatuses, systems, methods, and media are disclosed for heat-assisted magnetic recording (HAMR) that, in some examples, provide a HAMR medium with two soft underlayers (SULs) on opposing sides of a single heatsink layer. For example, a magnetic recording medium is provided that includes a lower SUL on a substrate. The lower SUL is configured and positioned within the medium to provide a first return path for magnetic flux from a magnetic recording head during a write operation. The medium also includes a heatsink layer on the lower SUL and an upper SUL on the heatsink layer. The upper SUL is configured and positioned within the medium to provide a second return path for magnetic flux from the magnetic recording head. A magnetic recording layer is provided on the upper SUL to store information during the write operation. Additional layers or films may be provided as well.

Abstract: A heat-assisted magnetic recording (HAMR) disk has a magnetic recording layer (typically a FePt chemically-ordered alloy), a seed-thermal barrier layer (typically MgO) below the recording layer, a heat-sink layer, and an optical-coupling multilayer of alternating plasmonic and non-plasmonic materials between the heat-sink layer and the seed-thermal barrier layer. Unlike a heat sink layer, the multilayer has very low in-plane and out-of-plane thermal conductivity and thus does not function as a heat sink layer. The multilayer's low thermal conductivity allows the multilayer to also function as a thermal barrier. Due to the plasmonic materials in the multilayer it provides excellent optical coupling with the near-field transducer (NFT) of the HAMR disk drive.

Abstract: A heat-assisted magnetic recording (HAMR) disk has a magnetic recording layer (typically a FePt chemically-ordered alloy), a seed-thermal barrier layer (typically MgO) below the recording layer, a heat-sink layer, and an optical-coupling multilayer of alternating plasmonic and non-plasmonic materials between the heat-sink layer and the seed-thermal barrier layer. Unlike a heat sink layer, the multilayer has very low in-plane and out-of-plane thermal conductivity and thus does not function as a heat sink layer. The multilayer's low thermal conductivity allows the multilayer to also function as a thermal barrier. Due to the plasmonic materials in the multilayer it provides excellent optical coupling with the near-field transducer (NFT) of the HAMR disk drive.

Abstract: A heat-assisted magnetic recording (HAMR) disk has a magnetic recording layer (typically a FePt chemically-ordered alloy), a seed-thermal barrier layer (typically MgO) below the recording layer, a heat-sink layer, and an optical-coupling multilayer of alternating plasmonic and non-plasmonic materials between the heat-sink layer and the seed-thermal barrier layer. Unlike a heat sink layer, the multilayer has very low in-plane and out-of-plane thermal conductivity and thus does not function as a heat sink layer. The multilayer's low thermal conductivity allows the multilayer to also function as a thermal barrier. Due to the plasmonic materials in the multilayer it provides excellent optical coupling with the near-field transducer (NFT) of the HAMR disk drive.

Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media, wherein the head comprises a write coil and a write pole. A test pattern is written to the magnetic media by applying a first current to the write coil. A second current is applied to the write coil while the head passes over the test pattern, wherein the second current has a polarity opposite the first current. After applying the second current to the write coil while the head passes over the test pattern, the test pattern is read from the magnetic media using the head to generate a first read signal, and a first noise power of the first read signal is measured. A degradation of the write pole is detected based on the first noise power measurement.

Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media, wherein the head comprises a write coil, a laser configured to heat the magnetic media during a write operation, and a read element. A test pattern is written to the magnetic media by applying a current to the write coil and a first bias to the laser. A second bias is applied to the laser while the head passes over the test pattern, and then the test pattern is read from the magnetic media using the head to generate a first read signal. A first noise power of the first read signal is measured, and at least one parameter of a noise power function is generated based on the first noise power measurement, wherein the noise power function is a function of at least the bias applied to the laser.

Abstract: A data storage device is disclosed comprising a head actuated over a magnetic media, wherein the head comprises a laser and a near field transducer (NFT). A thermal gradient produced in the magnetic media by the NFT is periodically measured, and a failure of the NFT is predicted based on a slope of the thermal gradient measurements.

Abstract: According to one embodiment, a multi-layer magnetic nanoparticle includes a core; a first magnetic layer deposited on a surface of the core; a second magnetic layer deposited on a surface of the first magnetic layer, and a third magnetic layer deposited on a surface of the second magnetic layer. The core, the first magnetic layer, the second magnetic layer, and the third magnetic layer comprise different magnetic anisotropies and/or saturation magnetizations with respect to each other.

Abstract: A heat-assisted magnetic recording (HAMR) medium has a non-magnetic multilayered overcoat on the recording layer. The overcoat includes a heat-dissipation layer, a diamond-like carbon (DLC) layer on and in contact with the heat-dissipation layer, and an optional interface layer between and in contact with the recording layer and the heat-dissipation layer. The heat-dissipation layer is a material with relatively high in-plane thermal conductivity, substantially higher than the in-plane thermal conductivity of both the DLC layer and the recording layer. The heat-dissipation layer laterally spreads the heat generated in the DLC layer by absorption of light from the near-field transducer to thereby reduce the temperature of the DLC layer. The optional interface layer is a material with relatively low thermal conductivity and increases the thermal resistance between the recording layer and the heat-dissipation layer.

Abstract: The present invention relates to a water-soluble polymer complex that includes a water-soluble block copolymer and a magnetic nanoparticle, wherein the water-soluble polymer complex has a nonzero net magnetic moment in the absence of an applied magnetic field at ambient temperatures. The water-soluble block copolymer is preferably a diblock or triblock copolymer and the magnetic nanoparticle is preferably a ferrimagnetic or ferromagnetic nanoparticle. The water-soluble complexes may be derivatized with reactive groups and conjugated to biomolecules. Exemplary water-soluble polymer complexes covered under the scope of the invention include PEG112-b-PAA40 modified CoFe2O4; NH2-PEG112-b-PAA40 modified CoFe2O4; PNIPAM68-b-PAA28 modified CoFe2O4; and mPEG-b-PCL-b-PAA modified CoFe2O4.

Abstract: A method according to one embodiment includes forming a first portion of a thin film writer structure on a substrate, forming a portion of a write gap at an initial position, a plane of deposition of the portion of the write gap being at an angle of greater than 0° and less than 90° relative to an upper surface of the first portion in the initial position, moving the writer structure to orient the plane of deposition of the portion of the write gap more toward perpendicular to a plane corresponding to a final media-facing surface of the writer structure than the orientation of the plane of deposition of the portion of the write gap in the initial position, and fixing the writer structure in place after the moving.

Abstract: A heat-assisted magnetic recording (HAMR) medium has a rhodium (Rh) or Rh-based alloy heat-sink layer. The Rh or Rh-based alloy does not roughen when annealed and thus does not require an intermediate layer between it and the MgO seed layer for the recording layer, so the MgO seed layer can be formed directly on and in contact with the Rh or Rh-based alloy heat-sink layer. The Rh or Rh-based alloy heat-sink layer is formed on a seed layer or multilayer that allows the Rh or Rh-based alloy to grow with the desired face-centered-cubic (fcc) crystalline structure.

Abstract: A heat-assisted magnetic recording (HAMR) medium includes a perpendicular magnetic recording layer (typically a chemically-ordered FePt alloy), a seed/thermal barrier layer (typically MgO) below the recording layer, and a heat-sink layer with anisotropic thermal conductivity below the seed/thermal barrier layer. The in-plane thermal conductivity of the heat-sink layer is greater than its out-of-plane thermal conductivity. The heat-sink layer may be selected from hexagonal boron nitride (h-BN), hexagonal graphite, and the 6H polytype of hexagonal silicon carbide (6H-SiC). If the heat-sink layer is h-BN, the h-BN layer is formed on a seed layer and has its c-axis oriented out-of-plane (substantially orthogonal to the surface of the medium substrate).

Abstract: A method according to one embodiment includes forming a first portion of a thin film writer structure on a substrate, forming a portion of a write gap at an initial position, a plane of deposition of the portion of the write gap being at an angle of greater than 0° and less than 90° relative to an upper surface of the first portion in the initial position, moving the writer structure to orient the plane of deposition of the portion of the write gap more toward perpendicular to a plane corresponding to a final media-facing surface of the writer structure than the orientation of the plane of deposition of the portion of the write gap in the initial position, and fixing the writer structure in place after the moving.