Sony Corporation

Tomoe Ozaki

Junichi Tachibana

Noboru Sekiguchi

Tetsuo Endo

Ryoichi Hiratsuka

Takashi Aizawa

Teruo Sai

Ichiro Kanagawa

Hikaru Terui

Kasumi Suzuki

Koji Suzuki

Yoichi Kanemaki

Kazuya Hashimoto

Jota Ito

Taketoshi Sato

Sogo Oikawa

Hiroto Atagi

Miho Abiko

A magnetic recording medium includes a flexible and elongated substrate, a soft magnetic layer having an average thickness of 10 nm or more to 50 nm or less, and a recording layer. The soft magnetic layer is disposed between the substrate and the recording layer, and a difference in Young's modulus between the magnetic recording medium and the substrate in a longitudinal direction of the substrate is 2.4 GPa or more.

Magnetic recording medium

A tape-like magnetic recording medium includes a reinforced substrate, and a recording layer arranged on the reinforced substrate, and the reinforced substrate includes a substrate that has a first face and a second face opposed to each other, and has an average thickness of 4 &#x3bc;m or smaller, and a metal layer that contains cobalt, arranged on the first face, the reinforced substrate by itself causing thereon a depth of indentation of 0.25 &#x3bc;m or shallower, when a 0.7-mm-diameter hard sphere is impressed against the second face under 5.0 gf load for 10 seconds.

Magnetic recording medium having reinforced substrate

To provide a magnetic recording tape and the like that have excellent magnetic properties and exhibit a favorable SNR. There are provided a magnetic recording tape and the like including at least: a base layer that includes a long film having flexibility; and a magnetic layer formed on a side of one main surface of the base layer, in which an under layer and a seed layer are provided in the stated order from a side of the magnetic layer toward a side of the base layer between the magnetic layer and the base layer, the underlayer contains at least Co and Cr, and has an average atomic number ratio represented by the following formula (1): CoCr(where y is within a range of 37&#x2264;y&#x2264;45.), and the seed layer formed directly on the base layer has a film thickness of 5 nm or more and 30 nm or less, and contains Ti and O and has an average atomic number ratio represented by the following formula (2): TiO(where x&#x2264;10.) or contains Ti&#x2014;Cr&#x2014;O and has an average atomic number ratio represented by the following formula (3): (TiCr)O(where x&#x2264;10.).

Magnetic recording tape and magnetic recording tape cartridge

There is provided a magnetic recording medium including a base; a seed layer; a foundation layer; and a recording layer, the seed layer being disposed between the base and the foundation layer, having an amorphous state, including an alloy containing Ti, Cr and O, a percentage of Ti being 30 atomic % to 100 atomic % based on a total amount of Ti and Cr contained in the seed layer, and a percentage of O being 15 atomic % or less based on a total amount of Ti, Cr and O contained in the seed layer. Also, a production method thereof is provided.

Magnetic recording medium and method of producing the same

A magnetic recording medium includes: an elongated substrate having flexibility; a first layer, being provided on the substrate, containing Cr, Ni, and Fe, and having a face-centered cubic lattice structure with a (111) plane preferentially oriented so as to be parallel to a surface of the substrate; a second layer, being provided on the first layer, containing Co and O, having a ratio of an average atomic concentration of O to an average atomic concentration of Co of 1 or more, and having a column structure with an average particle diameter of 3 nm or more and 13 nm or less; a third layer, being provided on the second layer, and containing Ru; and a perpendicular recording layer, being provided on the third layer.

A magnetic recording medium has a recording surface having an average surface roughness SRa of 3.0 nm or less, the number of projections having a height of 7.5 nm or more included in a unit region (where the unit region is a square region with each side having a length of 30 &#x3bc;m) of the recording surface is 256 or more, and the number of projections having a height of 15 nm or more included in the unit region of the recording surface is 0 or more and 104 or less.

Magnetic recording medium with controlled surface characteristics

A magnetic recording medium includes a long-shaped base substrate having flexibility, a soft magnetic layer, and a magnetic recording layer. A squareness ratio in a longitudinal direction of the base substrate is equal to or less than a squareness ratio in a short-side direction of the base substrate. The squareness ratio in the longitudinal direction of the base substrate is 30% or less.

A magnetic recording medium includes a substrate, a seed layer, an under layer, and a perpendicular recording layer having a granular structure. (Ms&#xb7;&#x3b1;&#x3b4;(1&#x2212;Rs)), Ms, and &#x3b1; satisfy (Ms&#xb7;&#x3b1;&#xb7;&#x3b4;(1&#x2212;Rs))&#x2264;0.1 [&#x3bc;&#xb7;emu&#xb7;(mm)], Ms&#x2265;450 [emu/cc], and &#x3b1;&#x2265;1.2. In the above formulas, Ms indicates a saturated magnetization amount, &#x3b1; indicates the gradient of a M-H loop around a coercive force Hc, &#x3b4; indicates the thickness of the perpendicular recording layer, and Rs indicates a squareness ratio.

There is provided a magnetic recording medium including a surface having a longitudinal direction and a lateral direction. An arithmetic average roughness Ra, a ratio PSD/PSD, and a ratio PSD/PSDon the surface satisfy Ra&#x2266;3.0 nm, PSD/PSD&#x2266;0.65, and 1.3&#x2266;PSD/PSD&#x2266;2.3, in which PSDis an average value of PSD values in a range from 0.15 &#x3bc;m to 0.4 &#x3bc;m in the longitudinal direction of the surface, PSDis an average value of PSD values in a range from 0.15 &#x3bc;m to 0.4 &#x3bc;m in the lateral direction of the surface, PSDis an average value of PSD values in a range from 0.4 &#x3bc;m to 5.0 &#x3bc;m in the longitudinal direction of the surface, and PSDis an average value of PSD values in a range from 0.4 &#x3bc;m to 5.0 &#x3bc;m in the lateral direction of the surface.

A magnetic recording medium includes a base material which has flexibility, a lower coating layer, and a recording layer, in which, in X-ray diffraction peaks, a value of &#x394;&#x3b8;where a diffraction peak of magnetic atoms which are included in the recording layer is measured by a locking curve method is 5&#xb0; or more to less than 10&#xb0;.

Magnetic recording medium having a recording layer with a diffraction peak of magnetic atoms

A method of manufacturing a metallic thin film type magnetic recording medium is provided. The method comprises the steps of arranging an initial substance of said recording medium in opposition to a plasma discharge electrode, said initial substance comprising a non-magnetic support base, a metallic layer capable of functioning as a metallic electrode formed on said non-magnetic support base and a metallic magnetic layer formed on said metallic layer, and forming a protection film on a surface of said initial substance of said recording medium by way of generating plasma discharge while feeding raw material gas between said metallic layer/said metallic magnetic layer and said plasma discharge electrode.

Metallic thin film type magnetic recording medium and method of manufacturing thereof

A magnetic recording medium of a metal thin-film type, which includes a magnetic layer and a carbon protective layer on a non-magnetic support member, and in which a non-magnetic metal thin-film is provided between the magnetic layer and the carbon protective layer, is provided. The magnetic recording medium thus produced can be run stably.

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Miyagi, Japan

Tomoe Ozaki