Fuji Photo Film Company, Limited

Kazuyuki Usuki

Toshio Ishida

Masakazu Nishikawa

Tadashi Yasunaga

Tsutomu Okita

Makoto Nagao

Kunihiko Sano

Kazutoshi Katayama

Masashi Aoki

Kenichi Moriwaki

Yoshihisa Usami

Masaki Satake

Hideomi Watanabe

Kunihiko Honda

A magnetic recording medium comprising; a nonmagnetic support; a first under layer which is constituted by a nonmetal element, per se, a compound consisting of nonmetal elements, or a compound containing titanium and a nonmetal element; a second under layer containing at least one element selected from the group consisting of chromium, titanium, iridium, platinum, palladium, ruthenium, rhodium, rhenium and osmium; and a magnetic layer which contains a ferromagnetic metal alloy containing at least cobalt, platinum and chromium, and a nonmagnetic compound, in this order.

Magnetic recording medium

In an information recording method of the present invention by carrying out recording data while carrying out tracking servo accurately, high density recording of signals at a good S/N can be carried out, and high density recording by a vertical magnetic recording system can be carried out. A magnetic disk comprises a magnetic recording layer, and the magnetic recording layer is magnetized in advance such that magnetized regions A and B having different magnetization directions are formed. At a time of recording data, vertical magnetic recording is carried out by a magnetic head while carrying out accurate tracking servo by optically tracking by a magneto-optical effect utilizing a difference in the magnetization directions of the magnetized regions A and B. Therefore, high-density recording at a good S/N is possible.

Information recording method using a vertical magnetic system

The present invention provides a magnetic recording medium such as a flexible disk which is capable of high-density recording and is excellent in magnetic property. The magnetic recording medium comprises a magnetic layer, including a cobalt-containing ferromagnetic alloy and a non-magnetic material, on at least one surface of a non-magnetic substrate, wherein the ferromagnetic alloy forms a columnar structure.

A magnetic recording medium comprising a flexible support and a magnetic layer selected from a cobalt/palladium multilayer film and a cobalt/platinum multilayer film.

There are provided an information recording medium which permits accurate tracking servo, and a method for recording and reproducing for an information recording medium which allows recording and reproducing of a signal at a favorable S/N by carrying out at least one of information recording and information reproduction while accurately performing tracking servo. A magneto-optic disk includes a magnetic recording layer for magnetically recording information. The magnetic recording layer is in advance magnetized for concentrically or spirally around the center of the disk in such a manner that magnetized regions are disposed such that adjacent regions are magnetized in different directions and alternately arranged in the radial direction of the disk. Accordingly, tracking can be continuously performed and accurate tracking servo can also be performed.

Magnetic information recording medium having regions magnetized in different directions, a method for recording and reproducing for the same, and a method of manufacturing the same

A magnetic disk, comprising a magnetic layer, a protective layer, and a lubricating layer coated at least on one surface of a flexible non-magnetic support member or a rigid non-magnetic support member, wherein the protective layer comprises a carbon film containing hydrogen, nitrogen, and rare gas elements, nitrogen content is 0.5-8.0 atom %, and rare gas content is 0.5-1.2 atom %, and a magnetic recording mode using a floppy disk, wherein magnetic signal is recorded and reproduced using a floppy disk device provided with a carbon protective layer on the surface of the head or the slider.

Magnetic recording medium and magnetic recording mode using floppy disk

A magnetic transfer method for magnetically transferring information signals such as servo signals from a master medium to a slave medium, capable of reducing a range of signal missing due to insufficient contact of the two mediums originating from an adhering substance, thus enhancing signal quality. When the master medium bearing an information signal and the slave medium are brought into close contact with each other, a transferring magnetic field is applied thereto, thus magnetically transferring the information signal from the master medium to the slave medium. An elastic member made of a material having an elastic property so as to deform in accordance with a surface shape of the slave medium during contact pressure application and to restore to an original surface shape thereof during release of the slave medium from the master medium can be interposed between a back of the slave medium and a pressing surface of a pressing support member.

Method of magnetically transferring information signal from master medium to slave medium

The present invention provides a magnetic recording medium having high recording density and excellent storage property, and it provides a floppy disk, which includes a magnetic disk incorporated in a shell having a liner on inner side thereof, the magnetic disk having a magnetic film formed at least on one side of a flexible support member, and the liner contains a rust preventive agent.

Floppy disk

A magnetic recording medium, comprising a magnetic layer containing a ferromagnetic metal thin film having micro-size projections on surface thereof and formed by vacuum film forming method and provided at least on one side of a nonmagnetic substrate, a carbon protective layer and a lubricant provided on said magnetic layer, a central axis of a diamond indenter of trilateral pyramid having a tip sharp angle of 90&deg; and a radius of curvature at tip of 35-50 nm being directed perpendicularly to the surface of the nonmagnetic substrate, pressure is applied on the carbon protective layer, and a load obtained when indentation depth of the indenter is 10-25 nm is divided by projection area of indenter contactor, and the quotient, i.e. micro-hardness, is within the range of 10-30 GPa.

A magnetic recording medium is disclosed, comprising a nonmagnetic support having a magnetic layer comprising a ferromagnetic metal thin film formed on at least one side surface of the nonmagnetic support, and an undercoating layer, wherein the undercoating layer is formed between the nonmagnetic support and the magnetic layer; and the undercoating layer comprises a silica film or metal oxide film comprising heat-resistant fine particles. A process for producing the magnetic recording medium is also disclosed.

Process of producing a magnetic recording medium

A magnetic recording medium comprises a non-magnetic substrate and a magnetic layer, which is constituted of a thin ferromagnetic metal film and is overlaid upon at least either one of the surfaces of the non-magnetic substrate. A prime-coating layer, which contains a silicone resin having an aromatic hydrocarbon group, is formed between the non-magnetic substrate and the thin ferromagnetic metal film. The magnetic recording medium can be produced easily and at a low cost. The prime-coating layer has smooth surface characteristics and is free from deterioration of surface characteristics and the occurrence of cracking even during the formation of a magnetic layer thereon with a sputtering process, which is accompanied by heating of the substrate. Also, the prime-coating layer causes no blocking to occur and is uniform and capable of being subjected to a wet-on-wet coating technique.

Magnetic recording medium and process for producing the same

A magnetic recording medium comprises a non-magnetic substrate and a magnetic layer, which is constituted of a thin ferromagnetic metal film and is overlaid upon at least either one of the surfaces of the non-magnetic substrate. A prime-coating layer, which has alkyl chains linked by an ether linkage to each other in a polysiloxane, is formed between the non-magnetic substrate and the thin ferromagnetic metal film. The magnetic recording medium is capable of being produced easily and at a low cost. The prime-coating layer has smooth surface characteristics, is free from deterioration of surface characteristics and the occurrence of cracking even during the formation of a magnetic layer thereon with a sputtering process, and causes no blocking to occur.

A coating film, which is constituted of a polysilazane, is formed on a substrate. The polysilazane in the coating film is then oxidized by being brought into contact with active oxygen or ozone, or by being exposed to light. A protective film, which is constituted of silica, is thereby formed on the substrate. An inorganic protective film is also provided, which comprises an inorganic oxide film, that is obtained by subjecting a polysilazane coating film to oxidation treatment, and fine particles contained in the inorganic oxide film.

Method for forming silica protective films

A magnetic recording medium excellent in running properties, durability and shelf stability. The magnetic recording medium has a magnetic layer of a ferromagnetic metal thin film formed over at least one surface of a non-magnetic base, with or without an inorganic protective layer formed on the magnetic layer. A surface layer consisting essentially of a salt of a phosphoric alkyl ester compound with an alkylamine compound, which is represented by the following formula (1) or (2), and a fluorine-containing carboxylic acid ester compound is provided on the magnetic layer or on the inorganic protective layer: ##STR1## where: R.sup.1 and R.sup.2, which may be the same or different from each other, are a hydrocarbon or fluorinated hydrocarbon group having from 2 to 26 carbon atoms; R.sup.A, R.sup.B, R.sup.C and R.sup.D are hydrogen, or a hydrocarbon or fluorinated hydrocarbon group having not more than 26 carbon atoms; and m is 1 or 2.

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Kanagawa, Japan

Kazuyuki Usuki