A magnetic recording medium including: a non-magnetic substrate; an underlayer; a perpendicular magnetic layer; a diffusion preventing layer; and a protective layer, wherein the underlayer, the perpendicular magnetic layer, the diffusion preventing layer, and the protective layer are layered on the non-magnetic substrate in this order, the perpendicular magnetic layer has a multi-layer structure, the perpendicular magnetic layer includes an uppermost layer and at least one layer other than the uppermost layer, the uppermost layer including Co or Fe in magnetic particles, and the at least one layer other than the uppermost layer including an oxide, the diffusion preventing layer is provided between the perpendicular magnetic layer and the protective layer, and the diffusion preventing layer includes at least one component selected from a group consisting of Si, Ti, Cr, B, and Ru, or either a carbide, an oxide, or both, of the at least one component.

A magnetic recording medium including: a non-magnetic substrate; an underlayer; a perpendicular magnetic layer; a diffusion preventing layer; and a protective layer, wherein the underlayer, the perpendicular magnetic layer, the diffusion preventing layer, and the protective layer are layered on the non-magnetic substrate in this order, the perpendicular magnetic layer has a multi-layer structure, the perpendicular magnetic layer includes an uppermost layer and at least one layer other than the uppermost layer, the uppermost layer including Co or Fe in magnetic particles, and the at least one layer other than the uppermost layer including an oxide, the diffusion preventing layer is provided between the perpendicular magnetic layer and the protective layer, and the diffusion preventing layer includes at least one component selected from a group consisting of Si, Ti, Cr, B, and Ru, or either a carbide, an oxide, or both, of the at least one component.

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.

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 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.

A magnetic recording medium includes a substrate, an underlayer provided above the substrate, and a magnetic layer provided on and in contact with the underlayer. The underlayer includes a compound represented by a general formula MgO.sub.(1-x), where x falls within a range of 0.07 to 0.25. The magnetic layer includes an alloy having a L1.sub.0 structure, and the alloy having the L1.sub.0 structure includes one or more elements selected from a group consisting of Al, Si, Ga, and Ge.

A magnetic recording medium includes a substrate, an underlayer, and a magnetic layer that are arranged in this order. The magnetic layer has a granular structure including magnetic grains having a L1.sub.0 crystal structure, and grain boundary parts having a volume fraction in a range of 25 volume % to 50 volume %. The magnetic grains have a c-axis orientation with respect to the substrate. The grain boundary parts include a material having a lattice constant in a range of 0.30 nm to 0.36 nm, or in a range of 0.60 nm to 0.72 nm.

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.

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.

The present invention is to provide an assisted magnetic recording medium including a substrate; an underlayer disposed on the substrate; a magnetic layer disposed on the underlayer and including an alloy having an L1.sub.0-type crystal structure; and a pinning layer disposed in contact with the magnetic layer, wherein the pinning layer includes a granular structure, the granular structure containing magnetic particles and grain boundaries, wherein the magnetic particles contain Co, and wherein the grain boundaries contain Y.sub.2O.sub.3 and/or an oxide of lanthanoid.