IP Library Granted Patent US 12,417,784
Granted Patent B2
US 12,417,784 · App. 18/840,356 · Granted Sep 16, 2025

Magnetic recording medium and cartridge

Inventor: Minoru Yamaga (Tokyo, JP)
Assignee: Sony Group Corporation
G11B5/5928G11B5/70678G11B5/714G11B5/7334G11B5/78G11B23/037
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Quick Facts
Patent No.
US 12,417,784
App. No.
18/840,356
Granted
Sep 16, 2025
Kind
B2
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.

Claims (44)

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 .

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 22, 2024
From: YAMAGA, MINORU
To: SONY GROUP CORPORATION
Reel/Frame 068365/0337 →
Priority Claims (1)
JP 2022-040364 · Mar 15, 2022 · national
Continuity (1)
Related Publication 20250166657A1 · May 22, 2025
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