Other

Masao Takano

Tsuyoshi Watanabe

Koji Takahashi

In a magnetic recording medium, surface roughness of a glass substrate and the variation of the surface roughness are suppressed to the predetermined range. Namely, the surface roughness (Rmax, Ra, Rq) and the relation (Rmax/Ra) between Rmax and Ra are restricted to the predetermined range. In this event, Ra is representative of a center-line mean roughness, Rmax is defined as a maximum height representative of a difference between a highest point and a lowest point and Rq is representative of a root mean square roughness. Thereby, crystal grains of an underlying layer and a magnetic layer formed thereon are equalized. Specifically, the surface roughness is specified by Rmax&lE;15 nm, Ra&lE;1 nm and Rq&lE;1.5 nm. Further, the ratio between the surface roughness Rmax and the surface roughness Ra is specified by Rmax/Ra&lE;30.

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Yamanashi, Japan

Masao Takano