Hitachi, Ltd.

Noriyoshi Goda

Naoto Endo

Yuzuru Hosoe

Akira Kato

Mitsuhiro Shoda

Masayuki Suzuki

Takaaki Shirakura

Shinji Fukaya

Shinya Matsuoka

Tatsuo Kawaide

Fuminobu Maruyama

A magnetic recording media formed of magnetic alloy layer of Co as the main component on a substrate through an under-layer, a protective layer and a lubricant layer, stacked in this order, said under-layer comprises plural under-layers including a first under layer of a substantially amorphous and a second under layer of crystalline stacked in this order; and a &#x394; BH[0.01, 50] defined by |BH[0.01%]&#x2212;BH[50%]|, as the difference between a height BH[0.01%] where a Bearing ratio is 0.01% and a height BH[50%] where a Bearing ratio is 50%, is not less than 3 nm and not more than 6 nm, where a Bearing Curve is given by a surface roughness curve of magnetic recording media.

Magnetic recording media and magnetic disk apparatus

A magnetic recording media formed of magnetic alloy layer of Co as the main component on a substrate through an under-layer, a protective layer and a lubricant layer, stacked in this order, said under-layer comprises plural under-layers including a first under layer of a substantially amorphous and a second under layer of crystalline stacked in this order; and a &Dgr;BH&lsqb;0.01, 50&rsqb; defined by &verbar;BH&lsqb;0.01%&rsqb;&minus;BH&lsqb;50%&rsqb;&verbar;, as the difference between a height BH&lsqb;0.01%&rsqb; where a Bearing ratio is 0.01% and a height BH&lsqb;50%&rsqb; where a Bearing ratio is 50%, is not less than 3 nm and not more than 6 nm, where a Bearing Curve is given by a surface roughness curve of magnetic recording media.

In a magnetic disk apparatus including a magnetic head and a magnetic disk medium having projections provided with a constant regularity, a rotating portion for driving the rotation of the magnetic disk medium is controlled by a control section in accordance with the regularity of the projections provided on the magnetic disk medium, a resonance frequency of the magnetic head and a relative speed of the magnetic disk medium to the magnetic head in order to prevent the resonance of the magnetic head from being caused by the projections of the magnetic disk medium. With such a construction, it is possible to realize the stabilization of floatation of the magnetic head in the magnetic disk apparatus, thereby providing a magnetic disk apparatus which has a low floating height and a high reliability.

Magnetic disk apparatus for a magnetic disk having projections provided

A magnetic recording medium for longitudinal recording uses a non-magnetic substrate made of glass ceramics that is suitable for high density recording with low noise. The magnetic recording medium is obtained by forming a magnetic recording film mainly containing cobalt on a non-magnetic glass substrate through a non-magnetic underlaying film made of Cr. Further a non-magnetic covering film is formed thereon. With respect to the crystal orientation of the faces of cobalt measured by X-ray diffraction, the diffraction intensity of the (0002) face is 1.5 times or more and 8 times or less the total diffraction intensities of the other faces.

Magnetic recording medium for longitudinal recording and method of

The present invention relates to a high-density magnetic recording medium (or 'media' as it is sometimes called) for a recording/reproduction system (such as thosed used in computer disk drives) and, more particularly, to a magnetic recording medium having a plurality of magnetic recording layers such that the uppermost layer is comparatively thinner and more densely structured than the lower magnetic recording layers. The present magnetic recording medium comprises a non-magnetic plated substrate, a non-magnetic underlying layer laminated on the plated substrate, a plurality of magnetic alloy layers including the uppermost layer laminated onto the underlying layer, a non-magnetic covering layer laminated onto the uppermost layer, and a lubricating layer formed onto the non-magnetic covering layer. The present invention improves the corrosion resistance of an alloy-type magnetic recording medium while maintaining or exceeding the recording/reproducing characteristics of such media, all at a desirable cost of production.

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Odawara, Japan

Noriyoshi Goda