Provided is a magnetic recording medium having a recording track width of 2 μm or less, including: a recording layer containing a powder of particles containing ε iron oxide, in which a squareness ratio measured in a transport direction is 30% or less, a squareness ratio S1 measured in the transport direction and a squareness ratio S2 measured in a width direction satisfy a relationship S1≥S2, a coercive force is 220 kA/m or greater and 310 kA/m or less, an activation volume is 8000 nm.sup.3 or less, and in a switching field distribution (SFD) curve, a peak ratio X/Y of a main peak height X and a height Y of a sub-peak near zero magnetic field is 3.0 or greater.

A magnetic recording medium includes a substrate, and a magnetic recording layer including magnetic grains having an L1.sub.0 structure. The magnetic recording layer is (001) oriented, and a surface of growth of the magnetic recording layer includes a (001) plane, a (111) plane, and planes equivalent to the (111) plane. An area ratio of the (111) plane and the planes equivalent to the (111) plane, represented by (A.sub.111+A.sub.111e)/(A.sub.001+A.sub.111+A.sub.111e), is in a range of 0.2 to 0.7, where A.sub.111 denotes an area of the (111) plane, A.sub.111e denotes an area of the planes equivalent to the (111) plane, and A.sub.001 denotes an area of the (001) plane.

It is an object to provide a magnetic recording medium that enables good reproduction even after long-term preservation and that has a small overall thickness.

The present technology provides a tape-shaped magnetic recording medium including a magnetic layer, a ground layer, a base layer, and a back layer, in which an average thickness tT of the magnetic recording medium is equal to or less than 5.3 μm, and, when the magnetic recording medium is subjected to dynamic viscoelasticity measurement at a frequency of 10 Hz and a temperature rise rate of 2° C./min, a difference between a maximum and a minimum of a viscosity term E″ in a temperature range of 0° C. to 80° C. is equal to or less than 0.18 GPa. In addition, the present technology also provides a tape cartridge including the tape-shaped magnetic recording medium.

Magnetic recording media including an interlayer configured to reduce lattice mismatch with adjacent layers of the media, such as an adjacent seed layer or an adjacent underlayer. In one example, an interlayer alloy is provided that includes tungsten (W) along with Cobalt (Co), Chromium (Cr), and Ruthenium (Ru). The atomic percentages of W and Ru within the interlayer are selected so that the amount lattice mismatch between the interlayer and its adjacent layers is below a preselected amount, such as below 3% as quantified by d-spacing. In some examples, the atomic percentage of Ru is greater than 25% and the atomic percentage of W is 2-10%. Methods of fabricating the magnetic recording media are also provided.

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 includes a substrate, an underlayer disposed above the substrate, and a first magnetic layer disposed above the underlayer. The first magnetic layer has a granular structure including magnetic grains having a L1.sub.0 structure, and grain boundaries. A content of the grain boundaries is in a range of 25 volume percent to 50 volume percent, and the grain boundaries include a chalcogenide-based layered material.

A method of producing a magnetic powder includes: performing heat treatment on first particles that contain triiron tetraoxide to prepare second particles that contain ε-iron oxide.

The invention provides a magnetic recording medium including a magnetic layer or a magnetic recording layer having a granular structure in which magnetic crystal grains are well separated from each other. The magnetic recording medium includes a substrate, a seed layer, and a magnetic recording layer, wherein the magnetic recording layer includes a first magnetic layer which is a continuous film consisting of an ordered alloy, and a second magnetic layer having a granular structure consisting of magnetic crystal grains consisting of an ordered alloy and a non-magnetic crystal grain boundary, and the seed layer consists of a material selected from the group consisting of an NaCl-type compound, a spinel-type compound, and a perovskite-type compound.

HAMR media with a magnetic recording layer having a reduced Curie temperature and methods of fabricating the HAMR media are provided. One such HAMR medium includes a substrate, a heat sink layer on the substrate, an interlayer on the heat sink layer, and a multi-layer magnetic recording layer on the interlayer. In such case, the multi-layer magnetic recording layer includes a first magnetic recording layer including an alloy selected from FePtX and CoPtX, where X is a material selected from the group consisting of Cu, Ni, and combinations thereof, a second magnetic recording layer on the first magnetic recording layer and having at least one material different from the materials of the first magnetic recording layer, and a third magnetic recording layer on the second magnetic recording layer and having at least one material different from the materials of the first magnetic recording layer.

The magnetic recording medium includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. The ferromagnetic powder is a ferromagnetic powder selected from the group consisting of a hexagonal strontium ferrite powder and an ε-iron oxide powder. The standard deviation of a height of the magnetic projection portion on a surface of the magnetic layer is in a range of 0.5 to 2.5 nm.