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:
Apr. 28, 2026
Filed:
Jan. 20, 2021
Sony Group Corporation, Tokyo, JP;
National Institute of Advanced Industrial Science and Technology, Tokyo, JP;
Takeshi Takahashi, Tokyo, JP;
Katsunori Maeshima, Tokyo, JP;
Minoru Yamaga, Tokyo, JP;
Masaru Terakawa, Tokyo, JP;
Natsuki Ichise, Tokyo, JP;
Tomoe Sato, Tokyo, JP;
Takashi Kataguchi, Tokyo, JP;
Atsuya Towata, Tokyo, JP;
Kimihiro Ozaki, Tokyo, JP;
Akihiro Matsumoto, Tokyo, JP;
Sony Group Corporation, Tokyo, JP;
Abstract
Provided is a magnetic recording medium that is able to achieve both an improvement in electromagnetic conversion characteristics and ensuring of high long-term reliability. The magnetic recording medium includes a magnetic layer and a base. The magnetic layer includes magnetic powders including ε-iron oxide. A ratio (Hrp/Hc) of residual coercivity (Hrp) measured in a perpendicular direction of the magnetic recording medium with use of a pulse magnetic field to perpendicular coercivity (Hc) of the magnetic recording medium is 2.0 or less. Saturation magnetization (Mst) per unit area of the magnetic recording medium is 4.5 mA or greater.