Magnetic recording medium and cartridge

Patent metadata

Field	Value
Publication number	US-12417784-B2
Application number	US-202318840356-A
Country	US
Kind code	B2
Filing date	Mar 7, 2023
Priority date	Mar 15, 2022
Publication date	Sep 16, 2025
Grant date	Sep 16, 2025

Abstract

A magnetic recording medium is a tape-shaped magnetic recording medium and includes: a base; and a magnetic layer. An average thickness of the magnetic recording medium is 5.30 μm or less. The magnetic layer contains a chlorine atom and a nitrogen atom, an atomic concentration ratio (A2/A1) of a maximum chlorine atomic concentration A1 obtained by measuring a chlorine atomic concentration of the magnetic layer in a thickness direction of the magnetic layer and a maximum nitrogen atomic concentration A2 obtained by measuring a nitrogen atomic concentration of the magnetic layer in the thickness direction of the magnetic layer is 0.50 or more and 0.75 or less. An average value of a protruding peak height Rpk of a surface of the magnetic layer is 2.10 nm or less.

First claim

The invention claimed is:

1. A magnetic recording medium, comprising:
a base; and
a magnetic layer,
an average thickness of the magnetic recording medium being 5.30 μm or less,
the magnetic layer including a chlorine atom and a nitrogen atom,
an atomic concentration ratio (A2/A1) of a maximum chlorine atomic concentration A1 obtained by measuring a chlorine atomic concentration of the magnetic layer in a thickness direction of the magnetic layer and a maximum nitrogen atomic concentration A2 obtained by measuring a nitrogen atomic concentration of the magnetic layer in the thickness direction of the magnetic layer being 0.50 or more and 0.75 or less,
an average value of a protruding peak height Rpk of a surface of the magnetic layer being 2.10 nm or less,
wherein the magnetic recording medium is tape-shaped.

2. The magnetic recording medium according to claim 1 , wherein
the magnetic layer has a servo pattern,
the servo pattern has a plurality of first magnetized regions and a plurality of second magnetized regions, and
the plurality of first magnetized regions and the plurality of second magnetized regions are asymmetric with respect to an axis parallel to a width direction of the magnetic recording medium.

3. The magnetic recording medium according to claim 2 , wherein
an inclination angle of each of the first magnetized regions with respect to the axis and an inclination angle of each of the second magnetized regions with respect to the axis are different from each other.

4. The magnetic recording medium according to claim 3 , wherein
of the inclination angle of each of the first magnetized regions the inclination angle of each of the second magnetized region, the larger inclination angle is 18° or more and 28° or less.

5. The magnetic recording medium according to claim 2 , wherein
a standard deviation σPES of PES (Position Error Signal) values obtained from a servo signal corresponding to the servo pattern is less than 50 nm in a full volume test up to 40 times in an environment of 26° C. and 80% RH.

6. The magnetic recording medium according to claim 1 , wherein
the maximum chlorine atomic concentration A1 is 4.5 atm % or more, 6.5 atm %.

7. The magnetic recording medium according to claim 1 , wherein
the atomic concentration ratio (A1/A2) is 0.55 or more and 0.71 or less.

8. The magnetic recording medium according to claim 1 , wherein
the magnetic layer includes a first binder and a second binder,
the first binder includes the chlorine atom, and
the second binder includes the nitrogen atom.

9. The magnetic recording medium according to claim 1 , wherein
the magnetic layer includes a vinyl chloride resin and a urethane resin.

10. The magnetic recording medium according to claim 1 , wherein
the magnetic layer includes protrusions on a surface thereof.

11. The magnetic recording medium according to claim 10 , wherein
the protrusions are formed by an abrasive and a carbon particle.

12. The magnetic recording medium according to claim 1 , further comprising
an underlayer,
an average thickness of the underlayer being 900 nm or less.

13. The magnetic recording medium according to claim 1 , wherein
an average thickness of the magnetic layer is 80 nm or less.

14. The magnetic recording medium according to claim 1 , wherein
an average thickness of the base is 4.40 μm or less.

15. The magnetic recording medium according to claim 1 , wherein
the magnetic layer includes a magnetic particle, and
the magnetic particle includes hexagonal ferrite, ε-iron oxide, or Co-containing spinel ferrite.

16. A cartridge, comprising:
the magnetic recording medium according to claim 1 .

Assignees

• Sony Group Corp

Inventors

• Yamaga Minoru

Classifications

• G11B23/037

  Single reels or spools · CPC title

• G11B5/78

  Tape carriers · CPC title

• G11B5/714 Primary

  characterised by the dimension of the magnetic particles · CPC title

• G11B5/70678

  Ferrites · CPC title

• G11B5/7334

  Base layer characterised by composition or structure · CPC title