A heat-assisted magnetic recording (HAMR) medium has a multilayered underlayer between the heat-sink layer and the recording layer. One embodiment of the underlayer is a multilayer of a thermal barrier layer consisting essentially of MgO and TiO, and a seed layer containing MgO and nitrogen (N) directly on the thermal barrier layer, with the recording layer on and in contact with the seed layer. The interface between the thermal barrier layer and the seed layer contains Ti and N, some of which may be present as TiN to act as a diffusion barrier to prevent diffusion of the Ti into the recording layer. The Ti-containing thermal barrier layer has a higher thermal resistivity than the conventional MgO thermal barrier/seed layer and thus allows for reduced laser power to the recording layer while still achieving a high thermal gradient at the recording layer.

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.

According to one embodiment, a disk device includes a base, a drive motor, disk-shaped magnetic recording media, a carriage supporting a magnetic head to be movable with respect to the magnetic recording medium, and a plurality of fixing members. The base includes a bottom wall and a side wall having a first corner and a second corner. The fixing member includes a support post erected on the bottom wall, and extending parts each extending from the support post between the magnetic recording media. The fixing members include a first fixing member provided between the magnetic recording medium and the first corner, a second fixing member provided between the magnetic recording medium and the second corner, and a third fixing member provided on a side facing the first fixing member.

According to one embodiment, a disk device includes a base, a drive motor, disk-shaped magnetic recording media, a carriage supporting a magnetic head to be movable with respect to the magnetic recording medium, and a plurality of fixing members. The base includes a bottom wall and a side wall having a first corner and a second corner. The fixing member includes a support post erected on the bottom wall, and extending parts each extending from the support post between the magnetic recording media. The fixing members include a first fixing member provided between the magnetic recording medium and the first corner, a second fixing member provided between the magnetic recording medium and the second corner, and a third fixing member provided on a side facing the first fixing member.

A magnetic recording medium includes a magnesium oxide underlayer including magnesium oxide, and a magnetic layer including an alloy having a L1.sub.0 structure and includes Fe or Co and Pt. The magnesium oxide has a peak of an O1s spectrum detected in a range of 531 eV to 533 eV when measured by X-ray photoelectron spectroscopy.

A magnetic recording medium includes a magnesium oxide underlayer including magnesium oxide, and a magnetic layer including an alloy having a L1.sub.0 structure and includes Fe or Co and Pt. The magnesium oxide has a peak of an O1s spectrum detected in a range of 531 eV to 533 eV when measured by X-ray photoelectron spectroscopy.

A magnetic recording medium is provided that includes a recording layer structure including a first magnetic recording layer, a second magnetic recording layer, a third magnetic recording layer, a fourth magnetic recording layer, and a plurality of nonmagnetic exchange coupling layers. The first magnetic recording layer is closest to a substrate and the fourth magnetic recording layer is farthest from the substrate. An amount of Co in the first magnetic recording layer is greater than or equal to the amount of Co in the second magnetic recording layer, the third magnetic recording layer, and the fourth magnetic recording layer.

A magnetic recording medium is provided that includes a recording layer structure including a first magnetic recording layer, a second magnetic recording layer, a third magnetic recording layer, a fourth magnetic recording layer, and a plurality of nonmagnetic exchange coupling layers. The first magnetic recording layer is closest to a substrate and the fourth magnetic recording layer is farthest from the substrate. An amount of Co in the first magnetic recording layer is greater than or equal to the amount of Co in the second magnetic recording layer, the third magnetic recording layer, and the fourth magnetic recording layer.

A tape-like magnetic recording medium includes a reinforced substrate, and a recording layer arranged on the reinforced substrate, and the reinforced substrate includes a substrate that has a first face and a second face opposed to each other, and has an average thickness of 4 μm or smaller, and a metal layer that contains cobalt, arranged on the first face, the reinforced substrate by itself causing thereon a depth of indentation of 0.25 μm or shallower, when a 0.7-mm-diameter hard sphere is impressed against the second face under 5.0 gf load for 10 seconds.

A magnetic recording medium includes a nonmagnetic substrate, a soft magnetic underlayer, an orientation control layer, a perpendicular magnetic layer, and a protection layer that are arranged in this order. The perpendicular magnetic layer includes a first magnetic layer and a second magnetic layer that are arranged in this order on the orientation control layer. The first magnetic layer has a granular structure including an oxide at grain boundary parts of magnetic grains, and the second magnetic layer is closest to the protection layer among layers within the perpendicular magnetic layer, and includes magnetic grains made of a CoCrPt alloy, and a nitride of carbon or a hydride of carbon.