Hitachi Maxell, Limited

Hitachi, Ltd.

Hitachi Maxwell, Ltd.

Osamu Kitakami

Hideo Fujiwara

Hideo Daimon

Tsuyoshi Maro

Kunio Wakai

Kazuetsu Yoshida

Yoichi Ogawa

Hiroyuki Suzuki

Masaaki Futamoto

Yoshihiro Shiroishi

Shinichiro Saito

Yukio Honda

Kazuo Shiiki

Yasutaro Uesaka

Takashi Nishimura

Toyoji Okuwaki

Hitoshi Iwata

Kazushige Imagawa

Kiyotaka Ojima

Youichi Ogawa

There is disclosed a magnetic recording medium comprising a non-magnetic substrate, a soft magnetic layer formed on the substrate, with or without a non-magnetic sublayer interposed therebetween, and a perpendicular magneto-anisotropic recording layer laminated on the soft magnetic layer, with or without a non-magnetic intermediate layer therebetween, the soft magnetic layer being composed of material saturation magnetization thereof being higher than at least that of the recording layer, and whose thickness is in the range of from 50 to 1,000 .ANG..

Magnetic recording medium

A medium in which a magnetic layer is composed mainly of Co and oxygen and has a principal axis of magnetic anisotropy rising unidirectionally at 20.degree. to 80.degree. to a nonmagnetic substrate surface, the coercive force Hs on the surface side of the magnetic layer is 600 to 2,000 Oe and the coercive force Hb on the substrate interfacial side is less than 600 Oe, the medium being produced by treating a nonmagnetic substrate surface with a plasma in an atmosphere of an inert gas or an oxygen gas, and then depositing an alloy composed mainly of Co on the above plasma-treated nonmagnetic substrate surface while an oxygen gas is introduced into the layer-forming atmosphere.

A magnetic recording medium comprising alumite made by anodic oxidation of aluminum or an aluminum alloy and comprising fine pores in which a ferromagnetic material is filled, wherein an in-plane remanence is at least 2.5 times greater than a perpendicular remanence and a magnetic recording medium of the above alumite, wherein the magnetic material is at least one material selected from the group consisting of Fe or Co, alloy mainly composed of Fe or Co, an Co or Fe containing a P element, and an alloy mainly composed of Co or Fe and containing the P element.

Provided according to the present invention are a perpendicular magnetic recording medium filled with a magnetic metal containing Fe as a main component in the fine pores of an alumite formed by anodic oxidation of a surface of an Al or Al alloy substrate, the particles of Fe in the filled magnetic metal being crystallographically discontinuous, and a process for the production thereof.

Magnetic recording medium comprising an aluminum substrate in which

A magnetic recording medium comprising a non-magnetic substrate and a magnetic layer composed of a ferromagnetic material having a face-centered cubic structure and at least one of a carbon, silicon, a hydrocarbon compound and an organosilicone compound, provided on the non-magnetic substrate, has a high coercive force, a good head running property and a high durability.

A perpendicular magnetic recording medium comprising a non-magnetic substrate and a magnetic layer which is formed on at least one surface of the substrate and comprises acicular particles of ferromagnetic metal oriented perpendicularly to a plane of the layer and an organic polymer filled in spaces between the acicular particles so as to surround the acicular particules, wherein a volume content of the organic polymer is about 5 to 55% by volume of the whole volume of the magnetic layer, which medium has not only good recording and reproducing characteristics but also improved durability.

Perpendicular magnetic recording medium and method for producing the same

The present invention provides a novel soft magnetic material superior in corrosion resistance which contains (a) a ferromagnetic metal and (b) a carbide of a ferromagnetic metal and/or a silicide of a ferromagnetic metal with at least one of (c) an amorphous carbon and/or an amorphous silicon and (d) a hydrocarbon polymer and/or a silicone polymer and which contains carbon atoms in an amount of 15 atomic % or less, preferably 9-15 atomic %, preferably prepared by the simultaneous vapor deposition of a ferromagnetic metal and a polymer.

Soft magnetic materials comprising 9 to 15 atomic percent carbon atoms

There is disclosed a magnetic recording medium comprising a non-magnetic substrate and a magnetic membrane composed of Co and oxygen formed thereon, which is characterized in that the saturated magnetic flux density of said magnetic layer is in the range of 8,400 G to 12,600 G, the oxygen content of said layer is in the range of 11 to 29 at %, and the residual magnetization in the in-plane direction of the membrane surface, Mr , and the residual magnetization in the perpendicular direction to the membrane surface Mr.perp., have a relation satisfying Mr /Mr.perp.&gt;1 and the C-axis of Co of the magnetic membrane is oriented in a perpendicular direction to the membrane surface.

A magnetic recording medium which comprises a non-magnetic substrate, a magnetic film formed on the substrate and a protective film provided on the magnetic film, the protective film being composed of at least two groups of element, the element in one group being at least one of B and C having a smaller atomic size, and a concentration of the element increasing from the interface side of the protective film with the magnetic film toward the opposite face side throughout the protective film has an improved durability against a magnetic head.

A magnetic recording medium comprising a non-magnetic substrate, a soft magnetic layer formed thereon, and a perpendicularly magnetizable layer formed on the soft magnetic layer, where at least the soft magnetic layer is a vapor deposited mixture layer composed of an organic material and a ferromagnetic material, has distinguished flexibility and durability.

Magnetic recording medium and process for preparing the same

A magnetic recording medium comprising a substrate, an underlayer provided on the substrate and having a high permeability magnetic film and a relative permeability in all directions in the film surface of not less than 800, and a recording medium layer provided on the underlayer and having a perpendicular anisotropy. The recording and reproduction characteristics of this magnetic recording medium do not vary even when the direction of movement thereof with respect to a magnetic head varies. When it is applied to a magnetic disc, preferable results can be obtained.

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Toride, Japan

Osamu Kitakami