A magnetic recording medium is used in a recording/reproduction apparatus having a shortest recording wavelength of not more than 75 nm, the magnetic recording medium including a recording layer that contains a powder of particles containing -iron oxide, in which a squareness ratio measured in a traveling direction of the magnetic recording medium is not more than 30%, a ratio (D.sub.max/D.sub.min) of an average longest diameter D.sub.max of the particles to an average shortest diameter D.sub.min of the particles satisfies a relationship of 1.0(D.sub.max/D.sub.min)1.1, an average thickness .sub.mag of the recording layer is not more than 100 nm, and a ratio (.sub.mag/D.sub.min) of the average thickness .sub.mag of the recording layer to the average shortest diameter D.sub.min of the particles satisfies a relationship of .sub.mag/D.sub.min5.

A magnetic recording medium includes: a substrate; a recording layer; and a layer being provided between the substrate and the recording layer, the layer containing a superelastic body.

There is provided an oriented body containing platinum group-substituted-6 iron oxide particles typified by Rh-substituted -iron oxide or Ru-substituted -iron oxide applicable to MAMR, MIMR, or F-MIMR system, and a technique related thereto, containing platinum group element-substituted -iron oxide particles in which a part of -iron oxide is substituted with at least one element of platinum group elements, as magnetic particles wherein the degree of orientation of the magnetic particles defined by the degree of orientation=SQ (direction of magnetization easy-axes)/SQ (direction of magnetization hard-axes) exceeds 5.0, and a coercive force exceeds 31 kOe.

The magnetic tape has on one surface of a nonmagnetic support a magnetic layer containing ferromagnetic powder and binder, and on the other surface of the nonmagnetic support, a backcoat layer containing nonmagnetic powder and binder, wherein the total thickness of the magnetic tape is less than or equal to 4.80 m, the backcoat layer contains one or more components selected from the group consisting of a fatty acid and a fatty acid amide, and a CH derived carbon, C, concentration calculated from a CH peak area ratio in a C1s spectrum obtained by X-ray photoelectron spectroscopy conducted at a photoelectron take-off angle of 10 degrees on a surface on the backcoat layer side of the magnetic tape ranges from 35 to 60 atom %.

The metal oxide particle dispersion for manufacturing a particulate magnetic recording medium contains metal oxide particles, solvent, and a polyester compound having one or more groups selected from the group consisting of a carboxyl group and a salt thereof, a phosphoric acid group and a salt thereof, a hydroxyl group and a nitrogen-substituted alkylene group, but substantially not containing ferromagnetic powder.