Hitachi, Ltd.

Yoshio Gobara

Hiroyuki Suzuki

Yoshihiro Shiroishi

Masaaki Hayashi

Sadao Hishiyama

Norikazu Tsumita

Yoshibumi Matsuda

Kazumasa Takagi

Makoto Sano

Hitoshi Oka

Masaki Ohura

Tsuneo Suganuma

Tomoyuki Ohno

Takaaki Shirakura

Hiroaki Okudaira

Nobuo Nakagawa

Masako Fujisawa

In a magnetic recording medium including an underlayer and a magnetic layer formed sequentially on a substrate, the underlayer is composed of a composite underlayer having an at least two-layered structure, the underlayer on the side of the substrate is made of a material providing low modulation to the magnetic recording medium while the underlayer on the side of the magnetic layer is made of a material providing a high S/N ratio to the medium. This makes it possible to obtain a magnetic recording medium having low modulation and high S/N ratio.

Magnetic recording medium

A magnetic recording medium comprises a non-magnetic substrate and a thin magnetic film, the thin magnetic film being composed mainly of Co, Ni and at least one of Zr and Hf, and a concentration of Zr, Hf or Zr and Hf as contained in the thin magnetic film being 0.1 to 30% by atom on the basis of the total of Co and Ni, and has a considerably higher corrosion resistance than that of the conventional magnetic recording medium having a thin Co-Ni magnetic film.

Disclosed is a magnetic recording medium in which an underlayer formed below a magnetic medium, in which a signal is written, is composed of a nickel alloy comprising 0.05 to 10 atom % of tungsten and 14 to 30 atom % of phosphorus. In this magnetic recording medium, the temperature for formation of magnetic medium and the temperature for formation of a protective film can be elevated over the levels adopted in the conventional techniques. Therefore, the magnetic characteristics and abrasion resistance can be improved. Furthermore, the magnetic recording medium is excellent in the mechanical strength and corrosion resistance. Accordingly, the reliability of the magnetic medium can be highly improved.

Magnetic recording medium having an amorphous, nonmagnetic

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Hadano, Japan

Yoshio Gobara