IP Library Granted Patent US 11,545,176
Granted Patent B2
US 11,545,176 · App. 17/658,003 · Granted Jan 3, 2023

Magnetic recording medium, magnetic storage apparatus, and method for manufacturing magnetic recording medium

Inventors: Takayuki Fukushima (Chiba, JP); Tomoo Shige (Chiba, JP); Yuji Umemoto (Chiba, JP); Kazuya Niwa (Chiba, JP)
Assignee: SHOWA DENKO K.K.
G11B5/653G11B5/012G11B5/127G11B5/656
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Quick Facts
Patent No.
US 11,545,176
App. No.
17/658,003
Granted
Jan 3, 2023
Kind
B2
Abstract

A magnetic recording medium includes a substrate, and a magnetic recording layer including magnetic grains having an L1 0 structure. The magnetic recording layer is (001) oriented, and a surface of growth of the magnetic recording layer includes a (001) plane, a (111) plane, and planes equivalent to the (111) plane. An area ratio of the (111) plane and the planes equivalent to the (111) plane, represented by (A 111 +A 111e )/(A 001 +A 111 +A 111e ), is in a range of 0.2 to 0.7, where A 111 denotes an area of the (111) plane, A 111e denotes an area of the planes equivalent to the (111) plane, and A 001 denotes an area of the (001) plane.

Claims (30)

1. A magnetic recording medium comprising:

a substrate; and

a magnetic recording layer including magnetic grains having an L1 0 structure, wherein

the magnetic recording layer is (001) oriented,

a surface of growth of the magnetic recording layer includes a (001) plane, a (111) plane, and planes equivalent to the (111) plane, and

an area ratio of the (111) plane and the planes equivalent to the (111) plane, represented by (A 111 +A 111e )/(A 001 +A 111 +A 111e ), is in a range of 0.2 to 0.7, where A 111 denotes an area of the (111) plane, A 111e denotes an area of the planes equivalent to the (111) plane, and A 001 denotes an area of the (001) plane.

2. The magnetic recording medium as claimed in claim 1 , wherein the magnetic grains have a crystal grain diameter less than or equal to 8 nm, and include at least one component selected from a group consisting of FePt, CoPt, FePd, and CoPd.

3. A magnetic recording medium comprising:

a substrate; and

a magnetic recording layer including magnetic grains having an L1 0 structure, wherein

the magnetic recording layer is (001) oriented,

a surface of growth of the magnetic recording layer includes a (001) plane, a (111) plane, and planes equivalent to the (111) plane, and

a kurtosis Rku at the surface of growth is in a range of 4 to 5.

4. The magnetic recording medium as claimed in claim 3 , wherein the magnetic grains have a crystal grain diameter less than or equal to 8 nm, and include at least one component selected from a group consisting of FePt, CoPt, FePd, and CoPd.

5. A magnetic storage apparatus comprising:

the magnetic recording medium according to claim 3 ; and

a magnetic head, including a first magnetic head element configured to read information from the magnetic recording medium, and a second magnetic head element configured to write information to the magnetic recording medium.

6. A magnetic storage apparatus comprising:

the magnetic recording medium according to claim 1 ; and

a magnetic head, including a first magnetic head element configured to read information from the magnetic recording medium, and a second magnetic head element configured to write information to the magnetic recording medium.

7. A method for manufacturing a magnetic recording medium, comprising:

forming a (001) oriented magnetic recording layer including magnetic grains having an L1 0 structure on a substrate, so that a (001) plane, a (111) plane, and planes equivalent to the (111) plane are formed as a surface of growth, and an area ratio of the (111) plane and the planes equivalent to the (111) plane, represented by (A 111 +A 111e )/(A 001 +A 111 +A 111e ), is in a range of 0.2 to 0.7, where A 111 denotes an area of the (111) plane, A 111e denotes an area of the planes equivalent to the (111) plane, and A 001 denotes an area of the (001) plane;

forming a protective film on the magnetic recording layer; and

polishing a surface of the protective film so that a kurtosis Rku thereof is in a range of 2.5 to 3.5.

8. The method for manufacturing the magnetic recording medium as claimed in claim 7 , wherein the forming the magnetic recording layer uses magnetic grains having a crystal grain diameter less than or equal to 8 nm, and including at least one component selected from a group consisting of FePt, CoPt, FePd, and CoPd.

9. A method for manufacturing the magnetic recording medium, comprising:

forming a (001) oriented magnetic recording layer including magnetic grains having an L1 0 structure on a substrate, so that a (001) plane, a (111) plane, and planes equivalent to the (111) plane are formed as a surface of growth, so that a kurtosis Rku of the surface of growth is in a range of 4 to 5;

forming a protective film on the magnetic recording layer; and

polishing a surface of the protective film so that a kurtosis Rku thereof is in a range of 2.5 to 3.5.

10. The method for manufacturing the magnetic recording medium as claimed in claim 9 , wherein the forming the magnetic recording layer uses magnetic grains having a crystal grain diameter less than or equal to 8 nm, and including at least one component selected from a group consisting of FePt, CoPt, FePd, and CoPd.

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 →
DECLARATION OF SUCCESSION Recorded Mar 8, 2023
From: SHOWA DENKO K.K.
To: RESONAC CORPORATION
Reel/Frame 063011/0157 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 5, 2022
From: FUKUSHIMA, TAKAYUKI; SHIGE, TOMOO; UMEMOTO, YUJI; NIWA, KAZUYA
To: SHOWA DENKO K.K.
Reel/Frame 059503/0724 →