Magnetic recording medium

• US 20040213948A1
• Filed: 01/23/2004
• Published: 10/28/2004
• Est. Priority Date: 01/24/2003
• Status: Abandoned Application

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Yamazaki, Nobuo, Saito, Shinji, Noguchi, Hitoshi
• Application Number:
  US10/762,506
• Publication Number:
  US 20040213948A1
• Time in Patent Office: Days
• US Class Current: 428/65.3
• CPC Class Codes: G11B 5/70 on a base layer
• CPC Class Codes: G11B 5/70678 Ferrites
• CPC Class Codes: G11B 5/714 characterised by the dimension of the magnetic particles

Abstract

Provided is a magnetic recording medium exhibiting good electromagnetic characteristics in high-density recording. The magnetic recording medium employed for magnetically recording signals with a track width equal to or less than 2.0 μm and reproducing the magnetically recorded signals, wherein said magnetic recording medium comprises a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder or comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder in this order on a nonmagnetic support. Said magnetic layer has a thickness equal to or less than 0.2 μm, and said hexagonal ferrite ferromagnetic powder has an average plate diameter being {fraction (1/30)} or less of the magnetically recorded track width as well as ½ or less of the thickness of the magnetic layer.

Claims

1. A magnetic recording medium employed for magnetically recording signals with a track width equal to or less than 2.0 μ

m and reproducing the magnetically recorded signals, wherein

said magnetic recording medium comprises a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder on a nonmagnetic support,

said magnetic layer has a thickness equal to or less than 0.2 μ

m, and

said hexagonal ferrite ferromagnetic powder has an average plate diameter being {fraction (1/30)} or less of the magnetically recorded track width as well as ½

or less of the thickness of the magnetic layer.

3. The magnetic recording medium according to claim 1, wherein a bit length of the magnetically recorded signal ranges from 0.04 to 0.2 μ

m.

5. The magnetic recording medium according to claim 1, wherein the magnetic layer has a coercive force ranging from 143 to 398 kA/m (1800 to 5000 Oe).

7. The magnetic recording medium according to claim 1, wherein the magnetic layer has a squareness (SQ) equal to or higher than 0.6.

9. The magnetic recording medium according to claim 1 for use in a magnetic recording and reproducing system wherein the magnetically recorded signal is reproduced with a magnetoresistive magnetic head (MR head).

2. A magnetic recording medium employed for magnetically recording signals with a track width equal to or less than 2.0 μ

m and reproducing the magnetically recorded signals, wherein

said magnetic recording medium comprises a nonmagnetic layer comprising a nonmagnetic powder and a binder and a magnetic layer comprising a hexagonal ferrite ferromagnetic powder and a binder in this order on a nonmagnetic support,

said magnetic layer has a thickness equal to or less than 0.2 μ

m, and

said hexagonal ferrite ferromagnetic powder has an average plate diameter being {fraction (1/30)} or less of the magnetically recorded track width as well as ½

or less of the thickness of the magnetic layer.

4. The magnetic recording medium according to claim 2, wherein a bit length of the magnetically recorded signal ranges from 0.04 to 0.2 μ

m.

6. The magnetic recording medium according to claim 2, wherein the magnetic layer has a coercive force ranging from 143 to 398 kA/m (1800 to 5000 Oe).

8. The magnetic recording medium according to claim 2, wherein the magnetic layer has a squareness (SQ) equal to or higher than 0.6.

10. The magnetic recording medium according to claim 2 for use in a magnetic recording and reproducing system wherein the magnetically recorded signal is reproduced with a magnetoresistive magnetic head (MR head).