Hitachi Maxell, Limited

Hitachi Maxwell, Ltd.

Hideaki Yamanaka

Satoshi Matsunuma

Enji Fujita

Tetsunori Koda

Nobuyuki Inaba

Katsusuke Shimazaki

Akira Yano

Tsuyoshi Onuma

Hiroyuki Kishi

Tetsunori Kouda

The invention provides an imprinting jig for transferring a pattern onto a thermoplastic sheet. The imprinting jig is provided with: a first die having a surface with a pattern; a die holder for supporting the first die; an elastic member placed between the first die and the die holder; and a second die opposing to the first die. The thermoplastic sheet is placed on the surface with the pattern of the first die. The imprinting jig optionally includes an adhesion reducing means between the elastic member and the first die or between the elastic member and the die holder.

Imprinting jig and imprinting apparatus

A magnetic recording medium based on the perpendicular magnetic recording system includes a substrate; a back layer which is formed on the substrate and which is formed of a soft magnetic material; an in-plane magnetized layer which is formed on the back layer and which has in-plane magnetization; and a recording layer which is formed on the in-plane magnetized layer and which has perpendicular magnetization, wherein the in-plane magnetized layer has a coercivity in an in-plane direction larger than a magnetic field generated by residual magnetization in a perpendicular direction of the recording layer. The influence on the reproduction output, caused by the mirror image effect of the soft magnetic back layer is reduced in wide range recording densities, thereby improving the resolution by decreasing the difference between the reproduction outputs of the magnetic recording medium at the low recording density and at the high recording density.

Magnetic recording medium and magnetic recording apparatus

A magnetic recording medium based on the perpendicular magnetic recording system has a substrate which is formed of a non-magnetic material, a soft magnetic back layer which is formed of a soft magnetic material and which is formed on the substrate, an underlayer which is formed on the soft magnetic back layer, and a recording layer which is formed of an alloy magnetic material which is mainly composed of CoPtCr and contains an oxide, and which is formed on the underlayer. The recording layer is formed of two or more magnetic layers having different oxide contents, and the layer, which is included in the two or more magnetic layers for constructing the recording layer and which is provided on a side nearest to the underlayer, has the highest oxide content in the recording layer. The magnetic recording medium has more excellent magnetic characteristics with less medium noise.

Magnetic recording medium, method for producing the same, and magnetic recording apparatus

A magnetic recording medium based on the perpendicular recording system, which has high coercivity and low medium noise, is provided by using an underlayer which has a thin film thickness and which makes it possible to improve the orientation of a recording layer. The magnetic recording medium based on the perpendicular recording system has the recording layer which is formed of a CoPtCr alloy magnetic film containing oxygen. The magnetic recording medium has such a structure that an adhesive layer, a soft magnetic back layer, the underlayer, the recording layer, and a protective layerare successively stacked on a substrate. A CoCrRu film, which has a film thickness of 5 nm to 20 nm, is used as the underlayer for the recording layer formed of the CoPtCr alloy magnetic film containing oxygen. Thus, it is possible to improve the crystalline orientation of the recording layer with the underlayer having the thin film thickness.

A magnetic recording mediumcomprises, on a substrate, a first orientation control layer, a second orientation control layer, a soft magnetic layer, a non-magnetic layer, a recording layer, and a carbon protective layer. The recording layeris formed of an FePt ordered alloy phase which exhibits ferromagnetism and an FePtordered alloy phase which exhibits paramagnetism. Accordingly, the magnetic coupling force, which acts between those of the FePt ordered alloy phase, is broken by the paramagnetic FePtordered alloy phase. The magnetic interaction between those of the FePt ordered alloy phase is reduced, and thus the noise is reduced. Further, the high density recording can be performed, and the medium is excellent in thermal stability, because the FePt ordered alloy having high crystalline magnetic anisotropy is used for the recording layer

A magnetic recording medium comprises a magnetic recording layerwhich is formed by using an ordered alloy containing B on a substratecontaining an amorphous component. A part of B in the ordered alloy is segregated in a grain boundary, and thus the magnetic interaction, which acts between magnetic grains, can be reduced. Accordingly, it is possible to form fine and minute magnetic domains in the magnetic recording layer, and it is possible to reduce the medium noise as well. The temperature, at which the substrate is heated during the film formation of the magnetic recording layer, can be suppressed to be low, because the ordering temperature for the ordered alloy containing B is lower than those of ordered alloys not containing B. Therefore, it is possible to use a substrate made of glass which is suitable for the mass production. The magnetic recording layeris also excellent in thermal stability because of the use of the ordered alloy having high magnetic anisotropy. According to the present invention, it is possible to provide the magnetic recording medium for high density recording which is excellent in thermal stability and which involves low medium noise.

Growing community of inventors

Toride, Japan

Hideaki Yamanaka