IP Library › Granted Patent US 11,100,949
Granted Patent B2
US 11,100,949 · App. 15/996,622 · Granted Aug 24, 2021

Magnetic recording medium

Inventors: Masashi Shirata (Kanagawa, JP); Takashi Fujimoto (Kanagawa, JP)
Assignee: FUJIFILM Corporation
G11B5/78G11B5/7085G11B5/70621G11B5/70642G11B5/714
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Quick Facts
Patent No.
US 11,100,949
App. No.
15/996,622
Granted
Aug 24, 2021
Kind
B2
Abstract

Provided is a magnetic recording medium including: a non-magnetic support; and a magnetic layer including particles of at least one kind of epsilon type iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and a compound represented by Formula (1), an abrasive, and a binding agent, at least on one surface of the non-magnetic support, in which an average equivalent circle diameter of the particles of the epsilon type iron oxide-based compound is 7 nm to 18 nm, an average equivalent circle diameter of the abrasive in a plan view of the magnetic layer is 20 nm to 1,000 nm, and a coefficient of variation of the equivalent circle diameter of the abrasive is 30% to 60%. In Formula (1), A represents at least one kind of metal element other than Fe and a satisfies a relationship of 0<a<2. ε-A a Fe 2-a O 3   (1).

Claims (18)

1. A magnetic recording medium comprising:

a non-magnetic support; and

a magnetic layer including particles of at least one kind of epsilon type iron oxide-based compound selected from the group consisting of ε-Fe 2 O 3 and a compound represented by Formula (1), an abrasive, and a binding agent, at least on one surface of the non-magnetic support,

wherein an average equivalent circle diameter of the particles of the epsilon type iron oxide-based compound is 7 nm to 18 nm,

an average equivalent circle diameter of the abrasive is 20 nm to 1,000 nm, and

a coefficient of variation of the equivalent circle diameter of the abrasive is 30% to 60%, in a plan view of an area of a surface of the magnetic layer having a vertical length of 4.3 μm and a horizontal length of 6.3 μm, observed using a scanning electron microscope (SEM):

ε-A a Fe 2-a O 3   (1)

in Formula (1), A represents at least one kind of metal element other than Fe and a satisfies a relationship of 0<a<2.

2. The magnetic recording medium according to claim 1 ,

wherein the epsilon type iron oxide-based compound includes the compound represented by Formula (1), and

A in Formula (1) is at least one kind of metal element selected from the group consisting of Ga, Al, In, Co, Zn, Ti, and Nb.

3. The magnetic recording medium according to claim 1 ,

wherein the average equivalent circle diameter of the abrasive in a plan view of the magnetic layer is 30 nm to 800 nm.

4. The magnetic recording medium according to claim 3 ,

wherein the average equivalent circle diameter of the abrasive in a plan view of the magnetic layer is 110 nm to 200 nm.

5. The magnetic recording medium according to claim 1 ,

wherein a recording system is a linear recording system.

6. The magnetic recording medium according to claim 1 , which is used in electromagnetic wave assist recording.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 4, 2018
From: SHIRATA, MASASHI; FUJIMOTO, TAKASHI
To: FUJIFILM CORPORATION
Reel/Frame 045978/0142 →
Priority Claims (1)
JP JP2017-114785 · Jun 9, 2017 · national
Continuity (1)
Related Publication 20180358046A1 · Dec 13, 2018