The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 25, 2026
Filed:
Mar. 29, 2023
Dowa Electronics Materials Co., Ltd., Tokyo, JP;
Fujifilm Corporation, Tokyo, JP;
Akifumi Onodera, Tokyo, JP;
Yasuto Miyamoto, Tokyo, JP;
Masaki Koshiko, Tokyo, JP;
Toshio Tada, Kanagawa, JP;
Takashi Fujimoto, Kanagawa, JP;
DOWA ELECTRONICS MATERIALS CO., LTD., Tokyo, JP;
FUJIFILM CORPORATION, Tokyo, JP;
Abstract
[Problem] A hexagonal barium ferrite magnetic powder formed of fine particles, wherein the anisotropic magnetic field distribution of a magnetic recording medium can be made to fall within a range effective in both improving the recording density and improving the SNR is provided. [Solution] A magnetic powder for a magnetic recording medium including magnetic particles in which Ba in hexagonal barium ferrite is partially substituted with Sr, wherein a Dx volume represented by the following formula (1) is 2,200 nmor less, an Sr/(Ba+Sr) molar ratio is 0.01 to 0.30, and an anisotropic magnetic field distribution is 1.00 or less.Dx volume (nm)=Dxc×π×(Dxa/2) (1) Here, Dxc is a crystallite diameter (nm) in a c-axis direction of a hexagonal ferrite crystal lattice, Dxa is a crystallite diameter (nm) in an a-axis direction of the same crystal lattice, and π is a circular constant.