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AssigneeTDK Corporation
InventorsHitoshi Taguchi, Kazumasa Iida, Kikoyuki Masuzawa, Yoshihiko Minachi
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The invention aims to provide a ferrite magnet having a high remanence and a high coercivity which are unachievable with prior art hexagonal ferrite magnets, by realizing a hexagonal ferrite whose saturation magnetization and magnetic anisotropy are both high; a ferrite magnet having a high remanence and a high coercivity as well as significantly improved temperature properties of coercivity and experiencing a minimized drop of coercivity even in a low temperature range; a ferrite magnet having a high remanence and a high coercivity using relatively coarse ferrite particles with a particle diameter in excess of 1 .mu.m; and a magnetic recording medium having a high remanence and thermal stability. To achieve these objects, an oxide magnetic material comprising a primary phase of ferrite with na hexagonal structure and having a composition containing A, R, Fe, and M wherein A is at least one element selected from Sr, Ba, Ca and Pb, with Sr being essentially contained in A, R is at least one element selected from Bi and rare earth elements inclusive of Y, with La being essentially contained in R, and M is Co or Co and Zn, the proportions in total of the respective elements relative to the quantity of the entire metal elements are A: 1-13 at %, R: 0.05-10 at %, Fe: 80-95 at %, and M: 0.1-5 at % is used to construct ferrite particles, sintered magnets, bonded magnets and magnetic recording media.
An oxide magnetic material comprising a primary phase of ferrite with a hexagonal structure and having a composition containing A, R, Fe, and M wherein
Ferrite particles comprising A, R, Fe, and M wherein
A sintered magnet comprising A, R, Fe, and M wherein
A sintered magnet comprising A, R, Fe, and M wherein
Dependencies are inferred from the claim text.