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

Patent metadata

Field	Value
Publication number	US-12159657-B2
Application number	US-202318455273-A
Country	US
Kind code	B2
Filing date	Aug 24, 2023
Priority date	Feb 26, 2021
Publication date	Dec 3, 2024
Grant date	Dec 3, 2024

Abstract

Provided are a magnetic recording medium including a non-magnetic support, and a magnetic layer including a ferromagnetic powder. The ferromagnetic powder is an ε-iron oxide powder, and an intensity ratio (Int1/Int2) of diffraction intensities obtained by an X-ray diffraction analysis of the magnetic layer using an In-Plane method after the magnetic layer is pressed at a pressure of 70 atm is 1.0 or more and 6.5 or less, a magnetic tape cartridge and a magnetic recording and reproducing device each including the magnetic recording medium.

First claim

What is claimed is:

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,
Int1/Int2, which is an intensity ratio of diffraction intensities obtained by an X-ray diffraction analysis of the magnetic layer using an In-Plane method after the magnetic layer is pressed at a pressure of 70 atm, is 1.0 or more and 6.5 or less,
the Int1 is a maximum value of a diffraction intensity in a range in which a diffraction angle 2θχ is 29.0° or more and 31.0° or less, and
the Int2 is a maximum value of a diffraction intensity in a range in which the diffraction angle 2θχ is 36.3° or more and 37.5° or less.

2. The magnetic recording medium according to claim 1 ,
wherein the intensity ratio is 1.5 or more and 6.0 or less.

3. The magnetic recording medium according to claim 1 ,
wherein the intensity ratio is 3.0 or more and 5.5 or less.

4. The magnetic recording medium according to claim 1 ,
wherein the ε-iron oxide powder contains a cobalt element.

5. The magnetic recording medium according to claim 4 ,
wherein the ε-iron oxide powder further contains an element selected from the group consisting of a gallium element and an aluminum element.

6. The magnetic recording medium according to claim 4 ,
wherein the ε-iron oxide powder further contains a titanium element.

7. 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.

8. 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.

9. The magnetic recording medium according to claim 1 ,
wherein the magnetic recording medium is a magnetic tape.

10. A magnetic tape cartridge comprising:
the magnetic tape according to claim 9 .

11. The magnetic tape cartridge according to claim 10 ,
wherein the intensity ratio is 1.5 or more and 6.0 or less.

12. The magnetic tape cartridge according to claim 10 ,
wherein the intensity ratio is 3.0 or more and 5.5 or less.

13. The magnetic tape cartridge according to claim 10 ,
wherein the ε-iron oxide powder contains a cobalt element.

14. The magnetic tape cartridge 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.

15. The magnetic tape cartridge according to claim 13 ,
wherein the ε-iron oxide powder further contains a titanium element.

16. The magnetic tape cartridge according to claim 10 ,
wherein the magnetic tape further comprises:
a non-magnetic layer containing a non-magnetic powder between the non-magnetic support and the magnetic layer.

17. The magnetic tape cartridge according to claim 10 ,
wherein the magnetic tape further comprises:
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.

18. A magnetic recording and reproducing device comprising:
the magnetic recording medium according to claim 1 .

Assignees

• Fujifilm Corp

Inventors

• Ozawa Eiki
• Fujimoto Takashi

Classifications

• G11B5/84

  Processes or apparatus specially adapted for manufacturing record carriers · CPC title

• G11B5/7356

  comprising non-magnetic particles in the back layer, e.g. particles of TiO2, ZnO or SiO2 · CPC title

• G11B5/735

  characterised by the back layer {(magnetic recording media substrates G11B5/739)} · CPC title

• G11B5/73

  Base layers {, i.e. all non-magnetic layers lying under a lowermost magnetic recording layer, e.g. including any non-magnetic layer in between a first magnetic recording layer and either an underlying substrate or a soft magnetic underlayer} · CPC title

• G11B5/714

  characterised by the dimension of the magnetic particles · CPC title