A magnetic recording medium, which is used in a recording and playback device in which the shortest recording wavelength is 75 nm or less, in which the magnetic recording medium has a recording layer including powder of ε-iron oxide-containing particles, the average particle size of the particles is 22 nm or less, the coercive force He is 220 kA/m or more and 320 kA/m or less, and the non linear transition shift is 20% or less.

A magnetic recording tape, in accordance with one aspect of the present invention, includes a substrate, an underlayer formed above the substrate, and a magnetic recording layer formed above the underlayer. The underlayer includes first encapsulated nanoparticles each comprising a first magnetic nanoparticle encapsulated by a first aromatic polymer, and a first polymeric binder binding the first encapsulated nanoparticles. The recording layer includes second encapsulated nanoparticles each comprising a second magnetic nanoparticle encapsulated by an encapsulating layer, and a second polymeric binder binding the second encapsulated nanoparticles.

The ε-iron oxide powder has an average particle size in a range of 5.0 to 16.0 nm and an uneven distribution of an M atom in a surface layer portion, in which the M atom is one or more kinds of atoms selected from the group consisting of an aluminum atom and an yttrium atom, and a content of the M atom with respect to 100 atom % of iron atoms is in a range of 4.0 to 9.5 atom %.

A magnetic recording tape, in accordance with one aspect of the present invention, includes a substrate, an underlayer formed above the substrate, and a magnetic recording layer formed above the underlayer. The underlayer includes first encapsulated nanoparticles each comprising a first magnetic nanoparticle encapsulated by a first aromatic polymer, and a first polymeric binder binding the first encapsulated nanoparticles. The recording layer includes second encapsulated nanoparticles each comprising a second magnetic nanoparticle encapsulated by an encapsulating layer, and a second polymeric binder binding the second encapsulated nanoparticles.

A product, according to one approach, includes a recording layer. The recording layer includes encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an encapsulating layer. A polymeric binder binds the encapsulated nanoparticles. A product, according to another approach, includes a recording layer. The recording layer includes encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an encapsulating layer, and a polymeric binder binding the encapsulated nanoparticles. An average diameter of the magnetic nanoparticles is in a range of 2 nanometers to 20 nanometers. An average thickness of the recording layer is less than 0.2 microns.

A product, according to one approach, includes an underlayer and a magnetic recording layer formed above the underlayer. The underlayer includes first encapsulated nanoparticles each comprising a first magnetic nanoparticle encapsulated by a first aromatic polymer, and a first polymeric binder binding the first encapsulated nanoparticles. The recording layer includes second encapsulated nanoparticles each comprising a second magnetic nanoparticle encapsulated by an encapsulating layer, and a second polymeric binder binding the second encapsulated nanoparticles.

A product, according to one approach, includes a recording layer. The recording layer includes encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an encapsulating layer. A polymeric binder binds the encapsulated nanoparticles. A product, according to another approach, includes a recording layer. The recording layer includes encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an encapsulating layer, and a polymeric binder binding the encapsulated nanoparticles. An average diameter of the magnetic nanoparticles is in a range of 2 nanometers to 20 nanometers. An average thickness of the recording layer is less than 0.2 microns.

A product, according to one approach, includes an underlayer and a magnetic recording layer formed above the underlayer. The underlayer includes first encapsulated nanoparticles each comprising a first magnetic nanoparticle encapsulated by a first aromatic polymer, and a first polymeric binder binding the first encapsulated nanoparticles. The recording layer includes second encapsulated nanoparticles each comprising a second magnetic nanoparticle encapsulated by an encapsulating layer, and a second polymeric binder binding the second encapsulated nanoparticles.

The -iron oxide powder has an average particle size in a range of 5.0 to 16.0 nm and an uneven distribution of an M atom in a surface layer portion, in which the M atom is one or more kinds of atoms selected from the group consisting of an aluminum atom and an yttrium atom, and a content of the M atom with respect to 100 atom % of iron atoms is in a range of 4.0 to 9.5 atom %.

A magnetic recording medium, which is used in a recording and playback device in which the shortest recording wavelength is 75 nm or less, in which the magnetic recording medium has a recording layer including powder of -iron oxide-containing particles, the average particle size of the particles is 22 nm or less, the coercive force He is 220 kA/m or more and 320 kA/m or less, and the non linear transition shift is 20% or less.