Invention Grant
- Patent Title: Magnetic recording medium using ϵ-iron oxide particle magnetic powder
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Application No.: US15420425Application Date: 2017-01-31
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Publication No.: US10255938B2Publication Date: 2019-04-09
- Inventor: Toshio Hiroi , Shinji Kawakami , Kenji Tanaka
- Applicant: Maxell Holdings, Ltd.
- Applicant Address: JP Kyoto
- Assignee: MAXELL HOLDINGS, LTD.
- Current Assignee: MAXELL HOLDINGS, LTD.
- Current Assignee Address: JP Kyoto
- Agency: Birch, Stewart, Kolasch & Birch, LLP
- Priority: JP2016-017020 20160201; JP2016-245424 20161219
- Main IPC: G11B5/706
- IPC: G11B5/706 ; G11B5/78 ; G11B5/725 ; G11B5/70 ; G11B5/008

Abstract:
A magnetic recording medium of the present invention includes a non-magnetic substrate, and a magnetic layer containing a magnetic powder. The magnetic powder is constituted by an ε-iron oxide powder. The magnetic layer has a squareness in a thickness direction of 0.65 or more. In a differential curve obtained by differentiating a hysteresis curve in the thickness direction of the magnetic layer, two or more peaks are present. In a case where, out of peaks in the same direction among the above-described peaks, a local maximum of a largest peak in a magnetic field range of +500 oersted [Oe] or more is taken as P1 and a local maximum of a largest peak in a magnetic field range of −500 oersted [Oe] or more and less than +500 oersted [Oe] is taken as P2, a relationship below is satisfied: 0.25≤P2/P1≤0.60.
Public/Granted literature
- US20170221513A1 MAGNETIC RECORDING MEDIUM Public/Granted day:2017-08-03
Information query
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