IP Library Granted Patent US 7,270,898
Granted Patent B2
US 7,270,898 · App. 10/955,545 · Granted Sep 18, 2007

Polycrystalline structure of ordered alloy and method of making the same

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Quick Facts
Patent No.
US 7,270,898
App. No.
10/955,545
Granted
Sep 18, 2007
Kind
B2
Abstract

Magnetic crystalline grains are spaced from each other on a base layer a polycrystalline structure. The magnetic crystalline grains are made of an ordered alloy. The ordered alloy serves to ensure the crystalline magnetic anisotropy energy larger than that of Co alloy in the magnetic crystalline grains. Such crystalline magnetic anisotropy energy reaches over 1×10 6 J/m 3 , for example. A sufficient magnetic crystalline magnetic anisotropy energy serves to reliably maintain the magnetization in finely structured magnetic crystalline grains. The ordered alloy may have the L1 0 structure, for example. The ordered alloy may include of Fe 50 Pt 50 (atom %), Fe 50 Pd 50 (atom %), Co 50 Pt 50 (atom %), and the like.

Claims (29)

1. A polycrystalline structure comprising:

a base layer; and

magnetic crystalline grains spaced from each other on the base layer so as to form island structures on a surface of the base layer, said magnetic crystalline grains being made of an ordered alloy,

wherein at least some of the magnetic crystalline grains have a bottom surface contacting the surface of the base layer.

2. A magnetic recording medium comprising:

a support body;

a base layer extending over a surface of the support body;

magnetic crystalline grains spaced from each other on the base layer so as to form island structures on a surface of the base layer, said magnetic crystalline grains being made of an ordered alloy, and

wherein at least some of the magnetic crystalline grains have a bottom surface contacting the surface of the base layer.

3. The polycrystalline structure according to claim 1 , wherein said ordered alloy has L 1 0 structure.

4. The polycrystalline structure according to claim 1 , wherein said base layer is made of non-magnetic crystals having a predetermined orientation.

5. The polycrystalline structure according to claim 1 , further comprising:

an isolating layer covering over the magnetic crystalline grains on the base layer; and

upper magnetic crystalline grains spaced from each other on a surface of the isolating layer, said upper magnetic crystalline grains being made of an ordered alloy.

6. The polycrystalline structure according to claim 5 , wherein said isolating layer is made of non-magnetic crystals having a predetermined orientation.

7. The polycrystalline structure according to claim 1 , further comprising:

a first isolating layer covering over the magnetic crystalline grains on the base layer;

first upper magnetic crystalline grains spaced from each other on a surface of the first isolating layer, said first upper magnetic crystalline grains being made of an ordered alloy;

a second isolating layer covering over the first upper magnetic crystalline grains on the first isolating layer; and

second upper magnetic crystalline grains spaced from each other on a surface of the second isolating layer, said second upper magnetic crystalline grains being made of an ordered alloy.

8. The polycrystalline structure according to claim 7 , wherein said first and second isolating layers are made of non-magnetic crystals having a predetermined orientation.

9. The magnetic recording medium according claim 2 , wherein said ordered alloy has L 1 0 structure.

10. The magnetic recording medium according claim 2 , wherein said base layer is made of non-magnetic crystals having a predetermined orientation.

11. The magnetic recording medium according claim 2 , further comprising:

an isolating layer covering over the magnetic crystalline grains on the base layer; and

upper magnetic crystalline grains spaced from each other on a surface of the isolating layer, said upper magnetic crystalline grains being made of an ordered alloy.

12. The magnetic recording medium according to claim 11 , wherein said isolating layer is made of non-magnetic crystals having a predetermined orientation.

13. The polycrystalline structure according to claim 1 , wherein each of the magnetic crystalline grains has a bottom surface contacting the surface of the base layer.

14. The magnetic recording medium according to claim 2 , wherein each of the magnetic crystalline grains has a bottom surface contacting the surface of the base layer.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 4, 2010
From: FUJITSU LIMITED
To: SHOWA DENKO K.K.
Reel/Frame 023950/0008 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 30, 2004
From: MUKAI, RYOICHI
To: FUJITSU LIMITED
Reel/Frame 015866/0091 →