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AssigneeHitachi, Ltd.
InventorsKatsuya Mitsuoka, Hiroshi Fukui, Makoto Aihara, Masanori Tanabe, Moriaki Fuyama, Shinji Narishige, Yutaka Sugita, Yoshihiro Shiroishi, Hajime Aoi, Yokuo Saitoh, Kanji Kawakami, Yoshikazu Tsuji, Masaaki Hayashi, Kazuo Nakagoshi
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A magnetic disc apparatus has a large recording density of 120 megabits per square inch or more, and defines a relationship among a pole thickness (Pt) of thin-film magnetic heads disposed in the magnetic disc apparatus, and a saturation flux density (Bs) of cores of the heads and a recording wavelength (.lambda.) for the thin film magnetic discs have a coercivity of 1800 Oe or more, wherein a levitation space between the head and the disc is 0.15 .mu.m or less.
A magnetic disc apparatus comprising a plurality of discs each having a track density of 1800 tracks per inch or more and a line recording density of 70 kilobits per inch or more, a plurality of thin-film magnetic heads, means for moving said magnetic heads relative to said magnetic discs, and disc rotating means for rotating said magnetic discs, wherein a levitation space between said thin-film magnetic heads and said thin-film magnetic discs is between 0.07 .mu.m and 0.15 .mu.m during recording and a recording wavelength (.lambda.) ranges from 0.3 to 0.97 .mu.m, said thin-film magnetic discs each having a magnetic film with a coercive force in its magnetic disc of 1800 Oe or more, and said magnetic heads record information on said magnetic discs and the product of a saturated flux density (B.sub.S) of magnetic head cores and a pole thickness (P.sub.T) of each of said magnetic heads satisfies the following formula in said recording wavelength:
Dependencies are inferred from the claim text.