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.

Date of Patent:
Jun. 08, 2021

Filed:

Nov. 17, 2017
Applicant:

Sony Corporation, Tokyo, JP;

Inventors:

Masaru Terakawa, Miyagi, JP;

Yoichi Kanemaki, Miyagi, JP;

Minoru Yamaga, Miyagi, JP;

Assignee:

Sony Corporation, Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B 5/706 (2006.01); G11B 5/712 (2006.01); G11B 5/714 (2006.01); G11B 5/70 (2006.01);
U.S. Cl.
CPC ...
G11B 5/70605 (2013.01); G11B 5/70 (2013.01); G11B 5/70642 (2013.01); G11B 5/712 (2013.01); G11B 5/714 (2013.01);
Abstract

A magnetic recording medium is used in a recording/reproduction apparatus having a shortest recording wavelength of not more than 75 nm, the magnetic recording medium including a recording layer that contains a powder of particles containing ε-iron oxide, in which a squareness ratio measured in a traveling direction of the magnetic recording medium is not more than 30%, a ratio (D/D) of an average longest diameter Dof the particles to an average shortest diameter Dof the particles satisfies a relationship of 1.0≤(D/D)≤1.1, an average thickness δof the recording layer is not more than 100 nm, and a ratio (δ/D) of the average thickness δof the recording layer to the average shortest diameter Dof the particles satisfies a relationship of δ/D≤5.


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