Tohoku University

Fuji Electric Co., Ltd.

Fuji Electric Device Technology Co., Ltd.

Satoshi Okamoto

Osamu Kitakami

Takehito Shimatsu

Hajime Aoi

Yutaka Shimada

Hiroyuki Uwazumi

Hideo Sato

Tadaaki Oikawa

Hiroyasu Kataoka

Yoshihisa Nakamura

Hiroaki Muraoka

Tomoaki Sakurai

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.

Disclosed are a magnetic thin film capable of providing a high uniaxial magnetic anisotropy, Ku, while suppressing the saturation magnetization Ms thereof, and a method for forming the film; and also disclosed are various devices to which the magnetic thin film is applied. The magnetic thin film comprises a Co-M-Pt alloy having an L11-type ordered structure (wherein M represents one or more metal elements except Co and Pt). For example, the Co-M-Pt alloy is a Co&#x2014;Ni&#x2014;Pt alloy of which the composition comprises from 10 to 35 at. % of Co, from 20 to 55 at. % of Ni and a balance of Pt. The magnetic thin film is applicable to perpendicular magnetic recording media, tunnel magneto-resistance (TMR) devices, magnetoresistive random access memories (MRAM), microelectromechanical system (MEMS) devices, etc.

Magnetic thin film and method for forming the film, and magnetic thin film-applied device

The present invention relates to a magnetic thin film containing a L1type Co&#x2014;Pt&#x2014;C alloy in which atoms are orderly arranged, and can realize an order degree excellent in regard to the L1type Co&#x2014;Pt&#x2014;C alloy to achieve excellent magnetic anisotropy of the magnetic thin film. Therefore, in the various application devices using the magnetic thin film, it is possible to achieve a large capacity process and/or a high density process thereof in a high level.

Magnetic thin film and method of manufacturing the same, and various application devices using the same

A first thin film including at least one transition metal selected from the group consisting of Co, Fe and Ni, and a second thin film including at least one platinum group element selected from the group consisting of Pt and Pd are prepared. Then, a multilayered structure where said first thin film and said second thin film are stacked is formed. Then, the multilayered structure is heated at the same time or after the formation of said multilayered structure, thereby to counter-diffuse constituent elements of said first thin film and said second thin film and alloy said at least one transition metal and said platinum group element.

Growing community of inventors

Sendai, Japan

Satoshi Okamoto