Sony Corporation

Yoichi Kanemaki

Masaru Terakawa

Minoru Yamaga

Eiji Nakashio

Katsunori Maeshima

Kazuya Hashimoto

Tomoe Sato

Nobuyuki Sasaki

Jun Hashimoto

Hiroyuki Kobayashi

Noboru Sekiguchi

Koji Suzuki

Takashi Kawashima

Ryoichi Hiratsuka

Tomoe Ozaki

Takashi Aizawa

Yutaka Okazaki

Futoshi Sasaki

Hikaru Terui

Teruo Sai

Yuta Akimoto

Hiroto Atagi

Yuuichi Masuzawa

Provided is a magnetic recording medium including: a support body; a base layer containing carbon particle powder and metal-containing particle powder; and a recording layer. In a recording surface, a maximum indentation depth h is 85≤h≤140, and a ratio d of a permanent strain to an elastic recovery (permanent strain/elastic recovery) is 0.95≤d≤1.25.

Magnetic recording medium

Provided is a magnetic recording medium having a recording track width of 2 &#x3bc;m or less, including: a recording layer containing a powder of particles containing &#x3b5; iron oxide, in which a squareness ratio measured in a transport direction is 30% or less, a squareness ratio S1 measured in the transport direction and a squareness ratio S2 measured in a width direction satisfy a relationship S1&#x2265;S2, a coercive force is 220 kA/m or greater and 310 kA/m or less, an activation volume is 8000 nmor less, and in a switching field distribution (SFD) curve, a peak ratio X/Y of a main peak height X and a height Y of a sub-peak near zero magnetic field is 3.0 or greater.

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 &#x3b5;-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.

Magnetic recording medium having -iron oxide-containing particles

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 magnetic recording medium includes a nonmagnetic support body, and a magnetic layer containing magnetic powder, in which the magnetic powder contains &#x3b5;-FeOcrystal (including a case of substituting a portion of Fe site with a metal element M), a product of residual magnetization and a thickness of the magnetic layer is from 0.5 mA to 6.0 mA, and a squareness ratio which is measured in a longitudinal direction of the magnetic layer is 0.3 or less.

The magnetic recording medium includes a long substrate body, and a magnetic layer including a powder of cubic crystal ferrite magnetic particles. The sum of a squareness ratio in the longitudinal direction and a squareness ratio in the vertical direction is 1.2 or more, and the difference of the squareness ratio in the longitudinal direction and the squareness ratio in the vertical direction is 0.15 or more.

Provided is a magnetic recording medium including: a recording layer containing a powder of particles containing &#x3b5; iron oxide, in which a ratio ((Hc(50)/Hc(25))&#xd7;100) of a coercive force Hc(50) measured in a thickness direction of the magnetic recording medium at 50&#xb0; C. and a coercive force Hc(25) measured in the thickness direction of the magnetic recording medium at 25&#xb0; C. is 95% or greater, the coercive force Hc(25) is 200 kA/m or greater, and a squareness ratio measured in a transport direction of the magnetic recording medium is 30% or less.

Magnetic recording medium having controlled coercive force ratio

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 &#x3b5;-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/D) of an average longest diameter Dof the particles to an average shortest diameter Dof the particles satisfies a relationship of 1.0&#x2264;(D/D)&#x2264;1.1, an average thickness &#x3b4;of the recording layer is not more than 100 nm, and a ratio (&#x3b4;/D) of the average thickness &#x3b4;of the recording layer to the average shortest diameter Dof the particles satisfies a relationship of &#x3b4;/D&#x2264;5.

Magnetic recording medium having a recording layer including epsilon-iron oxide

A magnetic recording medium according to a first technique includes an elongated substrate having a first surface and a second surface, a first reinforcing layer disposed on the first surface, a second reinforcing layer disposed on the second surface, an adhesion suppressing layer disposed on the second reinforcing layer, and a recording layer disposed on the first reinforcing layer or the adhesion suppressing layer.

Magnetic recording medium, laminate, and flexible device

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 &#x3b5;-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.

Magnetic recording medium having cubic ferrite or e-phase iron oxide magnetic particles

A magnetic recording medium includes a nonmagnetic support body, and a magnetic layer containing magnetic powder, in which the magnetic powder contains &#x3b5;:FeOcrystal (including a case of substituting a portion of Fe site with a metal element M), a product of residual magnetization and a thickness of the magnetic layer is from 0.5 mA to 6.0 mA, and a squareness ratio which is measured in a longitudinal direction of the magnetic layer is 0.3 or less.

A recording apparatus of a tape-shaped magnetic recording medium includes a transfer unit, a recording head, a signal-processing unit and a control unit. The transfer unit transfers a tape-shaped magnetic recording medium having an anisotropic property oblique with respect to the thickness direction in a forward or reversed direction. The recording head is positioned in such a way that a recording track is formed on the traveling tape-shaped magnetic recording medium, which is transferred by the transfer unit, in a direction parallel to the transfer direction of the tape-shaped magnetic recording medium. Connected to the recording head, the signal-processing unit receives a signal to be recorded onto the tape-shaped magnetic recording medium. The signal-processing unit then carries out signal processing required for an operation to write the signal to be recorded onto the tape-shaped magnetic recording medium. The control unit controls at least the operation of the signal-processing unit and detects the transfer direction of the tape-shaped magnetic recording medium transferred by the transfer unit, controlling the transfer unit on the basis of a result of detection.

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Miyagi, Japan

Yoichi Kanemaki