IP Library Granted Patent US 8,120,869
Granted Patent B2
US 8,120,869 · App. 12/863,399 · Granted Feb 21, 2012

Magnetic recording medium and magnetic recording/reproducing apparatus

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Quick Facts
Patent No.
US 8,120,869
App. No.
12/863,399
Granted
Feb 21, 2012
Kind
B2
Abstract

A magnetic recording medium having a magnetic pattern magnetically partitioning a magnetic layer, formed on a non-magnetic substrate, wherein the magnetic pattern is comprised of magnetic regions and non-magnetic regions surrounding each of the magnetic regions, the non-magnetic regions form depressions, the magnetic pattern comprises data areas and servo information areas, and the difference between the areal ratio of the depressions in the data areas and the areal ratio thereof in the servo information areas is within ±10%. The magnetic areas preferably comprise a magnetic layer having a granular structure comprised of magnetic grains each surrounded by an oxide, or a two-layer structure comprising the granular structure and a non-granular structure formed on the granular structure. The magnetic recording medium exhibits stable head-floating characteristics, and thus, the largest floating height can be reduced, and a high recording density can be obtained.

Claims (7)

1. A magnetic recording medium having a magnetic pattern magnetically partitioning a magnetic layer, formed on at least one surface of a non-magnetic substrate, characterized in that the magnetic pattern is comprised of magnetic regions and non-magnetic regions surrounding each of the magnetic regions, wherein the non-magnetic regions form depressions relative to the magnetic pattern, the magnetic pattern comprises data areas and servo information areas, and an absolute value of the difference between the areal ratio of the depressions in the data areas and the areal ratio of the depressions in the servo information areas is not larger than 10%.

2. The magnetic recording medium according to claim 1 , wherein the areal ratio of the depressions in the data areas is in the range of 10% to 50%.

3. The magnetic recording medium according to claim 1 , wherein the data areas form elevations constituting tracks in the data areas.

4. The magnetic recording medium according to claim 1 , wherein the depressions in the data areas and the depressions in the servo information areas have a depth in the range of 0.1 nm to 15 nm.

5. The magnetic recording medium according to claim 1 , wherein the magnetic regions comprise a magnetic layer having a granular structure comprised of magnetic grains each surrounded by an oxide.

6. The magnetic recording medium according to claim 1 , wherein the magnetic regions comprise a magnetic layer having a two-layer structure composed of a granular structure comprised of magnetic grains each surrounded by an oxide, and a non-granular structure, formed on the granular structure.

7. A magnetic recording/reproducing apparatus characterized by comprising, in combination, the magnetic recording medium as claimed in claim 1 ; a driving part for driving the magnetic recording medium in the recording direction; a magnetic head comprising a recording part and a reproducing part; means for moving the magnetic head in a relative motion to the magnetic recording medium; and a recording-and-reproducing signal treating means for inputting signal to the magnetic head and for reproducing output signal from the magnetic head.

Assignments (4)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 15, 2024
From: RESONAC CORPORATION
To: RESONAC HARD DISK CORPORATION
Reel/Frame 069167/0673 →
CHANGE OF ADDRESS Recorded Feb 14, 2024
From: RESONAC CORPORATION
To: RESONAC CORPORATION
Reel/Frame 066599/0037 →
CHANGE OF NAME Recorded Jun 23, 2023
From: SHOWA DENKO K.K.
To: RESONAC CORPORATION
Reel/Frame 064082/0513 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 1, 2010
From: FUKUSHIMA, MASATO
To: SHOWA DENKO K.K.
Reel/Frame 024924/0464 →