Sumitomo Special Metals Co., Ltd.

Neomax Co., Ltd.

Isamu Furuchi

Sachio Toyota

Shuji Anamoto

Yoshinori Kobayashi

Seiichi Hosokawa

A ferrite magnet powder and a ferrite magnet exhibiting improved magnetic properties are provided at a reduced manufacturing cost. An application product and manufacturing methods thereof are also provided. An oxide magnetic material includes, as a main phase, a ferrite having a hexagonal M-type magnetoplumbite structure. The material includes: A, which is at least one element selected from the group consisting of Sr, Ba, Pb and Ca; R, which is at least one element selected from the group consisting of Y (yttrium), the rare earth elements and Bi; Fe; and B (boron). The constituents A, R, Fe and B of the material satisfy the inequalities of 7.04 at %&#x2266;A&#x2266;8.68 at %, 0.07 at %&#x2266;R&#x2266;0.44 at %, 90.4 at %&#x2266;Fe&#x2266;92.5 at % and 0.015 at %&#x2266;B&#x2266;0.87 at % to the sum of the elements A, R, Fe and B.

Oxide magnetic material

The ferrite magnet powder of the present invention is magnet powder having, as the major phase, a La&mdash;Co magnetoplumbite ferrite where La and Co are substituted for Sr and Fe, respectively, represented by (1&minus;x)SrO.(x/2)La O .(n&minus;y/2)Fe O .yMO wherein x, y, and n represent mole ratios and satisfy 0.22&minus;0.02&lE;x&lE;0.22&plus;0.02, 0.18&minus;0.02&lE;y&lE;0.18&plus;0.02, and 5.2&lE;n&lE;6.0, where x>y.

Ferrite magnet powder and magnet using the magnet powder, and method for preparing them

An La&mdash;Co ferrite magnet powder, in which Sr and Fe are replaced with La and Co, respectively, is made by carrying out a calcination process at a temperature higher than 1300&deg; C. and equal to or lower than 1450&deg; C. Fe has a magnetic moment oriented upwardly with respect to a crystal c-axis at a number of sites thereof, and also has an opposite magnetic moment oriented downwardly with respect to the crystal c-axis at another number of sites thereof. And Fe is replaced with Co at the greater number of sites thereof. As a result, high coercivity is attained. In this manner, coercivity can be increased while suppressing decrease in saturation magnetization &sgr; .

Growing community of inventors

Saga, Japan

Isamu Furuchi