Sony Corporation

Yukari Yamada

Kenichi Sato

Yuichi Arisaka

Kazunobu Chiba

Ryoichi Hiratsuka

Takahiro Kawana

Toshiharu Kobayashi

Hirofumi Kondo

Mayumi Abe

A magnetic recording medium having at least a thin magnetic metal film and a carbon protective film formed on a non-magnetic substrate, wherein lubricating properties are afforded to a surface portion of the carbon protective film. Specifically, the carbon protective film having a lower layer exhibiting rust-proofing properties and/or an upper layer exhibiting lubricating properties is formed on the thin magnetic metal film. The magnetic recording medium has a good running performance, durability and preservability.

Magnetic recording medium and method for producing same

A magnetic recording medium, comprising a nonmagnetic substrate on the surface of which is deposited a magnetic layer. In one embodiment, the magnetic layer is formed of two thin films of magnetic metal and a layer of nonmagnetic material sandwiched therebetween, the layer of nonmagnetic material having a thickness no greater than 20% of the thickness of the magnetic layer, with the magnetic layer having an energy product of at least 100 gauss.multidot.cm.multidot.Oe as the product of its residual magnetic flux density, thickness and coercive force, and a surface roughness no greater than 0.003 .mu.m in center line average height. In another embodiment, the magnetic layer, which may be a single layer of magnetic metal film or may be of the aforementioned multiple layer construction, is vacuum deposited onto the substrate at an incident angle in the range of 30.degree. to 70.degree..

Magnetic recording medium

A method for magnetically recording digital video signals includes the steps of: converting input digital video signals into data segmented into blocks each composed of a plurality of pixel data; compression-coding the blocks of pixel data block-by-block; converting the compression-coded data into channel-encoded data; and supplying the channel-encoded data to magnetic heads on a rotary drum for recording by such heads on a magnetic recording medium constituted by a nonmagnetic base having thereon a magnetic layer of at least one thin magnetic metal film which has an energy product of at least 75 G.cm.Oe, with the surface roughness of said magnetic recording medium being at most 0.003 .mu.m in center line average height Ra, and with the surface roughness of said magnetic recording medium being at most 0.04 .mu.m in ten point average height Rz.

Digital signal recording on a magnetic recording medium having a

A magnetic recording medium comprised of a nonmagnetic support; a magnetic metal thin film formed on one major surface of the nonmagnetic support; and a protective film of a corrosion-resistant metal or a multilayer protective film structure consisting of a corrosion-resistant metal film and a durable protective film of a hard material. A multilayer protective film structure is formed by sputtering a corrosion-resistant protective film and a durable protective film over the magnetic metal thin film while the nonmagnetic support travels along the circumference of a cooling cylinder by using at least one target of a corrosion-resistant metal and at least one target of a hard material, or by using a composite target composed of at least one corrosion-resistant metal and one hard material. The protective film suppresses the corrosion of the magnetic metal thin film and improves the corrosion resistance and durability of the magnetic recording medium.

Magnetic recording medium and a method of fabricating the same

Magnetic recording medium and method for production thereof

A magnetic recording transfer method for use with the combination of a mother magnetic recording medium and a copy magnetic recording medium of a metal-deposited thin film type each. The two media are overlaid so that the column inclination of one medium will be opposite in direction to that of the other medium. This method comprises the step of externally applying a biased magnetic field to the combination of the media in such a manner that magnetized recordings on the mother medium will be transferred to the copy medium. The easy axis of the mother medium is positioned at an angle of 20.degree..+-.15.degree. with respect to the in-plane direction of the medium. The biased magnetic field is applied to the mother medium at an angle of 110.degree..+-.15.degree. with respect to the in-plane direction of the medium. This makes it possible to enhance the efficiency in transferring magnetic recording of the mother medium, especially the recordings of short wave lengths, and to minimize demagnetization of the mother medium. Furthermore, the ratio of the coercive force H.sub.CM of the mother medium to the coercive force H.sub.CC of the copy medium (H.sub. CM /H.sub.CC) is set to at most 1.5. This improves the magnetic recording transfer output of the copy medium and boosts the efficiency in the magnetic transfer of short wave magnetic recordings.

Growing community of inventors

Miyagi, Japan

Yukari Yamada