The magnetic recording medium includes a support and a magnetic layer containing a magnetic powder. The magnetic powder includes at least either of a magnetic particle containing a cubic ferrite and a magnetic particle containing an -phase iron oxide. The magnetic powder has a mean particle size of 10 nm or more and 14 nm or less, the magnetic powder has a mean aspect ratio of 0.75 or more and 1.25 or less, and the magnetic layer has a ten-point mean roughness Rz of 35 nm or less.

A magnetic recording medium includes a support, a recording layer, and a protective layer provided on at least one surface of the support and containing plate-shaped particle powder. The plate-shaped particle powder is stacked in an overlapping manner in a thickness direction of the protective layer such that main surfaces of plate-shaped particles face a surface of the support, and the plate-shaped particles have an average plate ratio of 60 or more.

The magnetic recording medium includes a support and a magnetic layer containing a magnetic powder. The magnetic powder includes at least either of a magnetic particle containing a cubic ferrite and a magnetic particle containing an -phase iron oxide. The magnetic powder has a mean particle size of 10 nm or more and 14 nm or less, the magnetic powder has a mean aspect ratio of 0.75 or more and 1.25 or less, and the magnetic layer has a ten-point mean roughness Rz of 35 nm or less.

A magnetic recording medium includes: a non-magnetic support; and a magnetic layer including a binding agent and a ferromagnetic powder including at least one epsilon-type iron oxide compound selected from the group consisting of -Fe.sub.2O.sub.3 and compound represented by Formula (1) (A represents at least one metal element other than Fe, and a satisfies 0<a<2), in which a value of magnetic field Hc with respect to magnetic field Hc is from 0.6 to 1.0, and Hc satisfies Expression (II): 119 kA/m<Hc<2380 kA/m. The magnetic field Hc is a magnetic field when the value of Expression (I): d.sup.2M/dH.sup.2 is zero, wherein a magnetization M, which is obtained by a magnetic field-magnetization curve obtained by measurement under specific conditions, is subjected to second derivative with respect to an applied magnetic field H, and magnetic field Hc is a magnetic field when the magnetization is zero in the curve.

-A.sub.aFe.sub.2-aO.sub.3(1)

Provided is a magnetic recording medium including: a non-magnetic support; and a magnetic layer including particles of at least one kind of epsilon type iron oxide-based compound selected from the group consisting of -Fe.sub.2O.sub.3 and a compound represented by Formula (1), and a binding agent, at least on one surface of the non-magnetic support, in which an average area Sdc of a magnetic cluster in a DC demagnetization state measured with a magnetic force microscope satisfies a relationship of 500 nm.sup.2<Sdc<3,000 nm.sup.2, and coercivity Hc satisfies a relationship of 319 kA/m<Hc<957 kA/m. In Formula (1), A represents at least one kind of metal element other than Fe and a satisfies a relationship of 0<a<2.

A.sub.aFe.sub.2-aO.sub.3(1)

Provided is a magnetic recording medium including: a non-magnetic support; and a magnetic layer including particles of at least one kind of epsilon type iron oxide-based compound selected from the group consisting of -Fe.sub.2O.sub.3 and a compound represented by Formula (1), an abrasive, and a binding agent, at least on one surface of the non-magnetic support, in which an average equivalent circle diameter of the particles of the epsilon type iron oxide-based compound is 7 nm to 18 nm, an average equivalent circle diameter of the abrasive in a plan view of the magnetic layer is 20 nm to 1,000 nm, and a coefficient of variation of the equivalent circle diameter of the abrasive is 30% to 60%. In Formula (1), A represents at least one kind of metal element other than Fe and a satisfies a relationship of 0<a<2.

-A.sub.aFe.sub.2-aO.sub.3(1)

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).

An apparatus is disclosed. The apparatus includes a storage layer, a first write layer, and a second write layer. The first write layer is disposed over the storage layer. The second write layer is disposed over the first write layer. The anisotropy field and magnetization associated with the second write layer at writing temperature is greater than anisotropy field and magnetization associated with the first write layer at the writing temperature.

A magnetic recording medium includes a support, a recording layer, and a protective layer provided on at least one surface of the support and containing plate-shaped particle powder. The plate-shaped particle powder is stacked in an overlapping manner in a thickness direction of the protective layer such that main surfaces of plate-shaped particles face a surface of the support, and the plate-shaped particles have an average plate ratio of 60 or more.

A surface-modified iron-based oxide magnetic particle powder has good solid-liquid separation property in the production process, has good dispersibility in a coating material for forming a coating-type magnetic recording medium, has good orientation property, and has a small elution amount of a water-soluble alkali metal, and to provide a method for producing the surface-modified iron-based oxide magnetic particle powder. The surface-modified iron-based oxide magnetic particle powder can be obtained by neutralizing a solution containing dissolved therein a trivalent iron ion and an ion of the metal, by which the part of Fe sites is to be substituted, with an alkali aqueous solution, so as to provide a precursor, coating a silicon oxide on the precursor, heating the precursor to provide e-type iron-based oxide magnetic powder, and adhering a hydroxide or a hydrous oxide of one kind or two kinds of Al and Y thereto.