Fuji Electric Co., Ltd.

Tohoku University

Hiroaki Muraoka

Hiroyuki Uwazumi

Takehito Shimatsu

Tadaaki Oikawa

Yutaka Shimada

Osamu Kitakami

Satoshi Okamoto

Hajime Aoi

Yoshihisa Nakamura

A perpendicular magnetic recording medium according to which both the thermal stability of the magnetization is good and writing with a magnetic head is easy, and moreover the SNR is improved. In the case of a perpendicular magnetic recording medium comprising a nonmagnetic substrate (), and at least a nonmagnetic underlayer (), a magnetic recording layer (), and a protective layer () formed in this order on the nonmagnetic substrate (), the magnetic recording layer () comprises a low Kregion () layer having a perpendicular magnetic anisotropy constant (Kvalue) of not more than 1&#xd7;10erg/cm, and a high Kregion () layer having a Kvalue of at least 1&#xd7;10erg/cm. Moreover, the magnetic recording layer () is made to have therein nonmagnetic grain boundaries that contain a nonmagnetic oxide and magnetically isolate crystal grains, which are made of a ferromagnetic metal, from one another.

Perpendicular magnetic recording medium

There is provided a perpendicular magnetic recording medium according to which both the thermal stability of the magnetization is good and writing with a magnetic head is easy, and moreover the SNR is improved. In the case of a perpendicular magnetic recording medium comprising a nonmagnetic substrate, and at least a nonmagnetic underlayer, a magnetic recording layerand a protective layerformed in this order on the nonmagnetic substrate, the magnetic recording layercomprises a low Kregionlayer having a perpendicular magnetic anisotropy constant (Kvalue) of not more than 1&#xd7;10erg/cm, and a high Kregionlayer having a Kvalue of at least 1&#xd7;10erg/cm. Moreover, the magnetic recording layeris made to have therein nonmagnetic grain boundaries that contain a nonmagnetic oxide and magnetically isolate crystal grains, which are made of a ferromagnetic metal, from one another.

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Sendai, Japan

Hiroaki Muraoka