Tdk Corporation

Wakako Okawa

Yoshinori Fujikawa

Eiji Kato

Chikara Ishizaka

Katsuo Sato

Yuki Nagamine

Syota Goto

Atsushi Yamaguchi

Koichi Otani

Masaya Kato

Katsuaki Yanagiuchi

A rare earth magnet includes main phase grains having an RTB type crystal structure. The main phase grains include Ga. A concentration ratio A (A=&#x3b1;Ga/&#x3b2;Ga) of the main phase grains is 1.20 or more, where &#x3b1;Ga and &#x3b2;Ga are respectively a highest concentration of Ga and a lowest concentration of Ga in one main phase grain.

Rare earth magnet

A rare earth magnet includes main phase grains having an RTB type crystal structure. The main phase grains include C. A concentration ratio A1 (A1=&#x3b1;C/&#x3b2;C) of the main phase grains is 1.50 or more, where &#x3b1;C and &#x3b2;C are respectively a highest concentration of C and a lowest concentration of C in one main phase grain.

A rare earth magnet includes main phase grains having an RTB type crystal structure. The main phase grains include B. A concentration ratio A (A=&#x3b1;B/&#x3b2;B) of the main phase grains is 1.05 or more, where &#x3b1;B and &#x3b2;B are respectively a highest concentration of B and a lowest concentration of B in one main phase grain.

The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises RTB crystal grains as the main phases and the crystal boundary phases among the RTB crystal grains. The microstructure of the sintered body is controlled by including crystal boundary phases containing at least R, T and M in the crystal boundary phases, wherein the relative atomic ratios of R, T and M are as follows, i.e., 25 to 35% for R, 60 to 70% for T and 2 to 10% for M.

Rare earth based magnet

The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises RTB crystal grains as the major phases and the crystal boundary phases among the RTB crystal grains. The microstructure of the sintered body is controlled by including crystal boundary phases containing at least R, T and M in the crystal boundary phases, wherein the relative atomic ratios of R, T and M are as follows, i.e., 60 to 80% for R, 15 to 35% for T and 1 to 20% for M.

The present invention provides a rare earth based magnet in which the demagnetization rate at a high temperature can be inhibited even if the amount of heavy rare earth element(s) such as Dy and Tb is evidently decreased compared to the past or no such heavy rare earth element is used. The rare earth based magnet of the present invention is a sintered magnet which comprises RTB crystal grains as the main phases and the crystal boundary phases among RTB crystal grains. The microstructure of the sintered body is controlled by at least containing the first crystal boundary phases and the second crystal boundary phases, wherein the first crystal boundary phases contain at least R-T-M in the ranges of 20 to 40 atomic % for R, 60 to 75 atomic % for T and 1 to 10 atomic % for M, and the second crystal boundary phases contains at least R-T-M in the ranges of 50 to 70 atomic % for R, 10 to 30 atomic % for T and 1 to 20 atomic % for M.

A magnetic pole of a magnetic head includes a narrow and a wide portion, and is formed of a plating film. An electrode film forms the plating film, and is provided only under at least a part of the wide portion. A manufacturing method for the magnetic head includes: forming a plating-film-accommodating layer with an accommodating groove; forming the electrode film in part of the accommodating groove; and forming the plating film in the accommodating groove by plating using the electrode film. The accommodating groove includes a narrow and a wide groove portion for accommodating the narrow and wide portions, respectively. The electrode film is provided only in at least a part of the wide groove portion. In the step of forming the plating film, the plating film grows from the surface of the electrode film, and the narrow groove portion is filled with a part of the plating film.

Thin-film magnetic head having a magnetic pole formed of a plating film

The method of measuring crystallographic orientations, crystal systems or the like of the surface of a specimen has steps of: irradiating the specimen with an ion beam; measuring the secondary electrons generated by the irradiation of the ion beam; repeating the irradiation of the ion beam and the measurement of the secondary electrons with each variation in an angle of incidence of the ion beam with respect to the specimen; and determining the crystalline state based on the variation in the amount of the secondary electrons corresponding to the variation of the angle of incidence.

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Tokyo, Japan

Wakako Okawa