Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2007-07-31
2007-07-31
Kim, Paul D. (Department: 3729)
Metal working
Method of mechanical manufacture
Electrical device making
C029S603030, C029S065000, C029S609000, C029S885000, C204S192150, C216S022000, C216S039000, C216S041000, C216S048000, C428S141000, C428S409000, C428S611000, C428S653000
Reexamination Certificate
active
11062652
ABSTRACT:
Disclosed is a magnetic recording medium and a method for manufacturing the same to provide a magnetic recording medium reducing medium noise and having excellent thermal stability. The magnetic recording medium includes a substantially amorphous seed layer and a polycrystal underlayer made of crystal grains having a substantially columnar structure, the polycrystal underlayer contacting thereto. In a boundary between the seed layer and the underlayer, fine grooves having a period up to as large as the magnetic layer crystal grain diameter are formed in the disc circumferential direction. Accordingly, the magnetic recording medium is allowed to have a grain shape with a value obtained by dividing the average grain diameter for the disc circumferential direction by the average grain diameter for the disc radial direction of no less than 0.5 and no more than 0.9, thus achieving simultaneously reduction of the medium noise and thermal stability.
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Hirayama Yoshiyuki
Takahashi Yoshio
Yahisa Yotsuo
A. Marquez, Esq. Juan Carlos
Fisher Esq. Stanley P.
Hitachi Global Storage Technologies Japan Ltd.
Kim Paul D.
Reed Smith LLP
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