MAGNETIC RECORDING MEDIUM

• US 20180358044A1
• Filed: 06/04/2018
• Published: 12/13/2018
• Est. Priority Date: 06/09/2017
• Status: Active Application

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Inventors: SHIRATA, Masashi, FUJIMOTO, Takashi
• Application Number:
  US15/996,678
• Publication Number:
  US 20180358044A1
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/70621 containing Co metal or alloys
• CPC Class Codes: G11B 5/70642 iron oxides

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-Fe₂O₃ and a compound represented by Formula (1), and a binding agent, at least on one surface of the non-magnetic support, in which an average area Sdc of a magnetic cluster in a DC demagnetization state measured with a magnetic force microscope satisfies a relationship of 500 nm²<Sdc<3,000 nm², and coercivity Hc satisfies a relationship of 319 kA/m<Hc<957 kA/m. 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_aFe_2-aO₃  (1)

Claims

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

-Fe₂O₃ and a compound represented by Formula (1), and a binding agent, at least on one surface of the non-magnetic support,

wherein an average area Sdc of a magnetic cluster in a DC demagnetization state measured with a magnetic force microscope satisfies a relationship of 500 nm²<

Sdc<

3,000 nm², and

coercivity Hc satisfies a relationship of 319 kA/m<

Hc<

957 kA/m,

ε

-A_aFe_2-aO₃ 

 

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

3. 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, Ti, Co, Zn, and Nb.

4. The magnetic recording medium according to claim 1,

wherein the average area Sdc of a magnetic cluster in a DC demagnetization state measured with a magnetic force microscope satisfies a relationship of 500 nm²<

Sdc<

1,500 nm².

5. The magnetic recording medium according to claim 4,

wherein the average area Sdc of a magnetic cluster in a DC demagnetization state measured with a magnetic force microscope satisfies a relationship of 550 nm²≤

Sdc≤

700 nm².

6. The magnetic recording medium according to claim 1,

wherein a recording system is a linear recording system.

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