IP Library Granted Patent US 11,894,032
Granted Patent B2
US 11,894,032 · App. 18/191,983 · Granted Feb 6, 2024

Magnetic recording medium having characterized vertical SFD, magnetic tape cartridge, and magnetic recording reproducing device

Inventors: Eiki Ozawa (Minamiashigara, JP); Takashi Fujimoto (Minamiashigara, JP)
Assignee: FUJIFILM Corporation
G11B5/70642G11B5/702G11B5/712
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Quick Facts
Patent No.
US 11,894,032
App. No.
18/191,983
Granted
Feb 6, 2024
Kind
B2
Abstract

Provided are: a magnetic recording medium including a non-magnetic support and a magnetic layer containing a ferromagnetic powder, in which the ferromagnetic powder is an ε-iron oxide powder, a vertical switching field distribution SFD of the magnetic recording medium is 0.20 or more and 3.00 or less at a measurement temperature of 25° C., and an inclination of SFD obtained from SFD at a measurement temperature of 10° C., SFD at a measurement temperature of 25° C., and SFD at a measurement temperature of 40° C. is 0.003° C. −1 or more and 0.080° C. −1 or less; a magnetic tape cartridge including the magnetic recording medium which is a magnetic tape; and a magnetic recording and reproducing device including the magnetic recording medium.

Claims (42)

1. A magnetic recording medium comprising:

a non-magnetic support; and

a magnetic layer containing a ferromagnetic powder,

wherein the ferromagnetic powder is an ε-iron oxide powder,

a vertical switching field distribution SFD of the magnetic recording medium is 0.20 or more and 3.00 or less at a measurement temperature of 25° C., and

an inclination of SFD obtained from SFD at a measurement temperature of 10° C., SFD at a measurement temperature of 25° C., and SFD at a measurement temperature of 40° C. is 0.003° C. −1 or more and 0.080° C. −1 or less.

2. The magnetic recording medium according to claim 1 ,

wherein the inclination of SFD is 0.005° C. −1 or more and 0.050° C. −1 or less.

3. The magnetic recording medium according to claim 1 ,

wherein the SFD at the measurement temperature of 25° C. is 0.50 or more and 2.00 or less.

4. The magnetic recording medium according to claim 2 ,

wherein the SFD at the measurement temperature of 25° C. is 0.50 or more and 2.00 or less.

5. The magnetic recording medium according to claim 1 ,

wherein the ε-iron oxide powder contains a cobalt element.

6. The magnetic recording medium according to claim 5 ,

wherein the ε-iron oxide powder further contains an element selected from the group consisting of a gallium element and an aluminum element.

7. The magnetic recording medium according to claim 5 ,

wherein the ε-iron oxide powder further contains an element selected from the group consisting of a titanium element and a tin element.

8. The magnetic recording medium according to claim 6 ,

wherein the ε-iron oxide powder further contains an element selected from the group consisting of a titanium element and a tin element.

9. The magnetic recording medium according to claim 2 ,

wherein the ε-iron oxide powder contains a cobalt element.

10. The magnetic recording medium according to claim 9 ,

wherein the ε-iron oxide powder further contains an element selected from the group consisting of a gallium element and an aluminum element, and further contains an element selected from the group consisting of a titanium element and a tin element.

11. The magnetic recording medium according to claim 3 ,

wherein the ε-iron oxide powder contains a cobalt element.

12. The magnetic recording medium according to claim 11 ,

wherein the ε-iron oxide powder further contains an element selected from the group consisting of a gallium element and an aluminum element, and further contains an element selected from the group consisting of a titanium element and a tin element.

13. The magnetic recording medium according to claim 4 ,

wherein the ε-iron oxide powder contains a cobalt element.

14. The magnetic recording medium according to claim 13 ,

wherein the ε-iron oxide powder further contains an element selected from the group consisting of a gallium element and an aluminum element, and further contains an element selected from the group consisting of a titanium element and a tin element.

15. The magnetic recording medium according to claim 1 , further comprising:

a non-magnetic layer containing a non-magnetic powder between the non-magnetic support and the magnetic layer.

16. The magnetic recording medium according to claim 1 , further comprising:

a back coating layer containing a non-magnetic powder on a surface side of the non-magnetic support opposite to a surface side on which the magnetic layer is provided.

17. The magnetic recording medium according to claim 1 ,

wherein the magnetic recording medium is a magnetic tape.

18. A magnetic tape cartridge comprising:

the magnetic tape according to claim 17 .

19. A magnetic recording and reproducing device comprising:

the magnetic recording medium according to claim 1 .

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 30, 2023
From: OZAWA, EIKI; FUJIMOTO, TAKASHI
To: FUJIFILM CORPORATION
Reel/Frame 063178/0955 →
Priority Claims (1)
JP 2020-165802 · Sep 30, 2020 · national
Continuity (2)
Continuation PCTJP2021034157 · Sep 16, 2021
Related Publication 20230238025A1 · Jul 27, 2023
Cited By (9)
US 12,300,276 US 12,300,286 US 12,300,288 US 12,308,054 US 12,308,058 US 12,308,059 US 12,322,425 US 12,334,125 US 12,380,924