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. 07, 2020
Filed:
Jul. 23, 2019
Showa Denko K.k., Tokyo, JP;
Takayuki Fukushima, Chiba, JP;
Koji Take, Chiba, JP;
Hisato Shibata, Chiba, JP;
Takehiro Yamaguchi, Chiba, JP;
Tomoo Shige, Chiba, JP;
Lei Zhang, Chiba, JP;
Chen Xu, Chiba, JP;
Yuji Umemoto, Chiba, JP;
Hiroshi Koyanagi, Chiba, JP;
Kazuya Niwa, Chiba, JP;
Tetsuya Kanbe, Chiba, JP;
SHOWA DENKO K.K., Tokyo, JP;
Abstract
A heat-assisted magnetic recording medium includes a substrate, an underlayer, and a magnetic layer including an alloy having a L1crystal structure and first and second layers, arranged in this order. Each of the first and second layers has a granular structure including C, SiO, and BN at grain boundaries. Vol % of the grain boundaries in each of the first and second layers is 25 to 45 vol %. Vol % of C in the first layer is 5 to 22 vol %, and a volume ratio of SiOwith respect to BN in each of the first and second layers is 0.25 to 3.5. Vol % of SiOin the second layer is greater than that of the first layer by 5 vol % or more. Vol % of BN in the second layer is smaller than that in the first layer by 2 vol % or more.