MAGNETIC RECORDING MEDIUM

• US 20170249966A1
• Filed: 11/16/2015
• Published: 08/31/2017
• Est. Priority Date: 11/18/2014
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: TACHIBANA, Junichi, ENDO, Tetsuo, OZAKI, Tomoe, TERUI, Hikaru
• Granted Patent: US 10,529,367 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/65 characterised by its composition G11B5/66 takes precedence
• CPC Class Codes: G11B 5/667 including a soft magnetic layer
• CPC Class Codes: G11B 5/7253 Fluorocarbon lubricant
• CPC Class Codes: G11B 5/7369 Two or more non-magnetic underlayers, e.g. seed layers or barrier layers
• CPC Class Codes: G11B 5/78 Tape carriers

Abstract

A magnetic recording medium includes a long-shaped base substrate having flexibility, a soft magnetic layer, and a magnetic recording layer. A squareness ratio in a longitudinal direction of the base substrate is equal to or less than a squareness ratio in a short-side direction of the base substrate. The squareness ratio in the longitudinal direction of the base substrate is 30% or less.

Claims

1. A magnetic recording medium comprising a long-shaped base substrate having flexibility, a soft magnetic layer, and a magnetic recording layer, wherein

a squareness ratio in a longitudinal direction of the base substrate is equal to or less than a squareness ratio in a short-side direction of the base substrate, and

the squareness ratio in the longitudinal direction of the base substrate is 30% or less.

2. The magnetic recording medium according to claim 1, wherein both of the squareness ratios in the longitudinal direction and the short-side direction of the base substrate are 10% or less.

3. The magnetic recording medium according to claim 2, wherein both of the squareness ratios in the longitudinal direction and the short-side direction of the base substrate are 5% or less.

4. The magnetic recording medium according to claim 1, wherein a direction of a magnetization easy axis of the soft magnetic layer is the longitudinal direction of the base substrate.

5. The magnetic recording medium according to claim 1, wherein the soft magnetic layer includes a first soft magnetic layer, an intermediate layer, and a second soft magnetic layer.

6. The magnetic recording medium according to claim 5, wherein a direction of a magnetization easy axis in both of the first soft magnetic layer and the second soft magnetic layer is the longitudinal direction of the base substrate.

7. The magnetic recording medium according to claim 1, further comprising at least one of a foundation layer and an intermediate layer provided between the soft magnetic layer and the magnetic recording layer.

8. The magnetic recording medium according to claim 7, wherein the foundation layer includes Ti and Cr.

9. The magnetic recording medium according to claim 7, wherein the foundation layer includes a first foundation layer and a second foundation layer.

10. The magnetic recording medium according to claim 9, wherein

the first foundation layer is provided on the soft magnetic layer side and includes Ti and Cr, and

the second foundation layer is provided on the intermediate layer side and includes Ni and W.

11. The magnetic recording medium according to claim 7, wherein the intermediate layer includes Ru.

12. The magnetic recording medium according to claim 7, wherein the intermediate layer includes a first intermediate layer and a second intermediate layer.

13. The magnetic recording medium according to claim 12, wherein the first intermediate layer and the second intermediate layer include Ru.

14. The magnetic recording medium according to claim 1, wherein the recording layer has a granular structure in which a grain including Co, Pt, and Cr is separated by an oxide.

15. The magnetic recording medium accordion to claim 1, further including a foundation layer provided between the base substrate and the soft magnetic layer,

wherein the foundation layer has an amorphous state and includes Ti and Cr.

16. The magnetic recording medium according to claim 1, wherein the base substrate is a film.

17. The magnetic recording medium according to claim 1, further comprising a lubrication layer including at least one kind of a carboxylic compound represented by General Formula (1) below.

General Formula (1):

18. The magnetic recording medium according to claim 1, further comprising a lubrication layer that includes one or both of carboxylic compounds represented by General Formulas (2) and (3) below.

General Formula (2):

19. The magnetic recording medium according to claim 18, wherein Rf has the total carbon number of 6 to 50, also has the total carbon number of fluorohydrocarbon group of 4 to 20, and is saturated or unsaturated fluorine-containing hydrocarbon.