Sony Corporation

Sony Group Corporation

Takashi Aizawa

Noboru Sekiguchi

Tomoe Ozaki

Minoru Yamaga

Tetsuo Endo

Junichi Tachibana

Tooru Sato

Teruo Sai

Ryoichi Hiratsuka

Koji Suzuki

Yoichi Kanemaki

Shin Saito

Kazuya Hashimoto

Atsuhiro Abe

Hikaru Terui

Sogo Oikawa

Hiroto Atagi

An object is to provide a magnetic recording medium having favorable crystal orientation characteristics and exhibiting a high SNR. The present technology provides a magnetic recording medium having a layer structure including a recording layer, a ground layer, and a base layer in this order, in which the ground layer includes a first ground layer on the recording layer side and a second ground layer on the base layer side, the first ground layer contains a nonmagnetic oxide, the first ground layer has a thickness of 2 nm or more and 10 nm or less, and the second ground layer has a thickness of 40 nm or more. Furthermore, the present technology also provides a magnetic recording cartridge including the magnetic recording medium.

Magnetic recording medium

A magnetic recording medium is provided and includes a magnetic layer, a non-magnetic layer, a base layer and a back layer, wherein an average thickness tof the magnetic recording medium is t&#x2264;5.3 a dimensional change amount &#x394;w in a width direction with respect to a change in tension in a longitudinal direction is 700 ppm/N&#x2264;&#x394;w, a thickness of the non-magnetic layer is 2.0 &#x3bc;m or less, a squareness ratio measured in a vertical direction of the magnetic recording medium is 65% or more, and the magnetic layer includes a magnetic powder.

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.

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

A film-forming apparatus and a method for manufacturing a magnetic recording medium are provided. The film-forming apparatus includes a rotating body which moves a base material with a strip shape which has flexibility, a plurality of cathodes which are provided to oppose a rotating surface of the rotating body; and a plurality of accommodating sections which accommodate each of the plurality of cathodes. The method includes sequentially film-forming a plurality of thin films on a base material using a plurality of cathodes which are provided on a moving path of the base material while moving the base material with a strip shape which has flexibility. Each of the plurality of cathodes is accommodated in a plurality of accommodating sections.

Film-forming apparatus and method for manufacturing magnetic recording medium

A magnetic recording medium is provided and includes a magnetic layer, a non-magnetic layer, a base layer and a back layer, wherein an average thickness tof the magnetic recording medium is t&#x2264;5.3 &#x3bc;m, a dimensional change amount &#x394;w in a width direction with respect to a change in tension in a longitudinal direction is 700 ppm/N&#x2264;&#x394;w, a thickness of the non-magnetic layer is 2.0 &#x3bc;m or less, a squareness ratio measured in a vertical direction of the magnetic recording medium is 65% or more, and the magnetic layer includes a magnetic powder.

There is provided a magnetic recording medium of which an average thickness tis t&#x2264;5.6 &#x3bc;m, a dimensional change amount &#x394;w in a width direction with respect to a change in tension in a longitudinal direction is 660 ppm/N&#x2264;&#x394;w, a squareness ratio in a vertical direction is 65% or more, and a width deformation coefficient b during long-term storage in a case where a long-term storage width change amount Y is defined as Y=blog(t) is &#x2212;0.06 &#x3bc;m&#x2264;b&#x2264;0.06 &#x3bc;m.

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 flexible substrate, an amorphous seed layer, an under layer containing Ru, and a recording layer having a granular structure. The seed layer is provided between the substrate and the under layer. The under layer has a thickness in a range of 5 to 50 nm.

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Miyagi, Japan

Takashi Aizawa