Magnetic recording media, its fabrication technique, and hard disk drive

• US 20070116989A1
• Filed: 11/22/2006
• Published: 05/24/2007
• Est. Priority Date: 11/24/2005
• Status: Abandoned Application

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ikekame, Hiroshi, Igarashi, Masukazu, Tsuchiya, Yuko
• Application Number:
  US11/602,957
• Publication Number:
  US 20070116989A1
• Time in Patent Office: Days
• US Class Current: 428/828.100
• CPC Class Codes: G11B 5/855 Coating only part of a support with a magnetic layer

Abstract

Provided is a medium fabrication technique, a recording medium and a hard disk drive, which achieve high recording density. To this end, (a) a magnetic layer is deposited on a substrate, and (b) a nano particle layer is deposited on the magnetic layer. Then, (c) the magnetic layer is etched by use of the nano particle layer as a mask, and (d) the nano particle layer is removed to form artificial magnetic grains, and thus an artificial granular magnetic recording medium is obtained.

Claims

1. A magnetic recording medium comprising:

artificially patterned magnetic grains which are fabricated by forming a nano particle thin film over a magnetic recording layer and processing the magnetic recording layer under the nano particle thin film into fine shapes by use of the nano particle thin film as a mask, wherein

the plurality of magnetic grains constitute one recorded bit, and

the magnetic grains each have a grain diameter of not less than 1 nm and not more than 10 nm, and have grain diameter dispersion of not more than 10%.

2. The magnetic recording medium as recited in claim 1, wherein

the patterned magnetic grains are magnetic grains made of any one of Fe, a material essentially containing Fe, Co and a material essentially containing Co.

3. The magnetic recording medium as recited in claim 1, wherein

the patterned magnetic grains are magnetic grains which have a multilayer periodic structure including a thin film made of any one of Fe, a material essentially containing Fe, Co and a material essentially containing Co, and a thin film made of any one of Pt, a material essentially containing Pt, Pd and a material essentially containing Pd.

4. The magnetic recording medium as recited in claim 1, wherein

a ratio of grain area to distance area is in a range of 3/7 to 5/5.

5. The magnetic recording medium as recited in claim 1, wherein

at least one layer made of a material having higher magnetic permeability than the magnetic grains is formed over and/or under the patterned magnetic grains.

6. A method of fabricating a magnetic recording medium including artificially patterned magnetic grains, wherein

the plurality of magnetic grains constitute one recorded bit,

the method comprising the steps of:

forming a nano particle thin film over a magnetic recording layer; and

processing the magnetic recording layer under the nano particle thin film into fine shapes by use of the nano particle thin film as a mask.

7. The method of fabricating a magnetic recording medium as recited in claim 6, the method further comprising the step of

forming at least one thin film between the magnetic recording layer and the nano particle thin film.

8. The method of fabricating a magnetic recording medium as recited in claim 6, wherein

the nano particle thin film is a thin film made of nano particles including at least one kind of material selected from the group consisting of Au, Pt, Pd, polystyrene, silica (SiO₂) and alumina (Al₂O₃), in which the nano particles are substantially regularly arranged in a monolayer, the nano particles are substantially spherical in shape, and the nano particles each have a certain fixed grain diameter of not less than 1 nm and not more than 10 nm, and have grain diameter dispersion of not more than 10%.

9. A hard disk drive comprising:

a magnetic recording medium including a magnetic recording layer;

a driving unit for driving the magnetic recording medium;

a magnetic head for performing a read and a write on the magnetic recording medium;

means for moving the magnetic head relatively to the magnetic recording medium;

means for outputting a recording signal to the magnetic head; and

means for reproducing an output signal from the magnetic head, wherein

the magnetic recording medium is a magnetic recording medium in which two or more artificially patterned magnetic grains constitute one recorded bit, and

the magnetic grains each have a grain diameter of not less than 1 nm and not more than 10 nm, and have grain diameter dispersion of not more than 10%.