Recording medium, method of manufacturing fullerene thin film, recording reproducing apparatus, information recording method, and information reading method

Patent metadata

Field	Value
Publication number	US-10008232-B2
Application number	US-201615529614-A
Country	US
Kind code	B2
Filing date	Jun 28, 2016
Priority date	Jun 30, 2015
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

According to the present invention, there is provided a recording medium comprising a substrate, a platinum layer formed on the substrate and having a (111) plane preferentially oriented, and a fullerene single crystal thin film formed on the platinum layer, and configured to be a recording layer, wherein an average value of average surface roughness Ra's with respect to four or more visual fields measured by using an atomic force microscope in a surface of the fullerene thin film is 0.5 nm or less.

First claim

The invention claimed is:

1. A recording medium comprising:
a substrate;
a platinum layer formed on the substrate and having a (111) plane preferentially oriented; and
a fullerene thin film formed on the platinum layer and configured to be a recording layer,
wherein an average value of average surface roughness Ra's with respect to four or more visual fields measured by using an atomic force microscope in a surface of the fullerene thin film is 0.5 nm or less.

2. The recording medium according to claim 1 ,
wherein the fullerene thin film is a single crystal thin film.

3. The recording medium according to claim 1 ,
wherein a rocking curve half-value width of a (111) diffraction peak in X-ray diffraction of the platinum layer is 0.1° or less.

4. The recording medium according to claim 1 ,
wherein a rocking curve half-value width of a (220) diffraction peak in X-ray diffraction of the platinum layer is 4° or less.

5. The recording medium according to claim 1 ,
wherein the substrate has a disk shape.

6. The recording medium according to claim 5 ,
wherein in a head flight test which is performed by rotating the recording medium, and using a DFH (Dynamic Flying Height) head, an AE (Acoustic Emission) output voltage is 0.1 V or less at the time of seeking the DFH head above the surface of the fullerene thin film.

7. The recording medium according to claim 1 ,
wherein the substrate is a sapphire substrate.

8. A recording reproduction apparatus comprising:
the recording medium according to claim 1 .

9. The recording reproducing apparatus according to claim 8 , further comprising:
a medium driving unit that rotatably drives the recording medium;
a reading/writing head that performs writing of information, and reading of the recorded information with respect to the recording medium by an electrical method;
a head driving unit that moves the reading/writing head relatively to the recording medium; and
a recording reproducing signal processing system that performs processing of an electrical signal in order to perform reading/writing of information with respect to the recording medium by the reading/writing head.

10. An information recording method of recording information in the fullerene thin film by using the recording medium according to claim 1 , that is a disk shaped recording medium,
wherein the information is recorded in the fullerene thin film by, while the recording medium is rotating, making a writing head approach the surface of the fullerene thin film of the recording medium, moving the writing head in an approximately radial direction of the recording medium, positioning the writing head at a desired track of concentric tracks, and locally applying a voltage of a predetermined intensity to the fullerene thin film with the writing head.

11. An information reading method of reading information which is recorded in the fullerene thin film by using the information recording method according to claim 10 ,
wherein the recorded information is read by, while the recording medium is rotating, making a reading head approach the surface of the fullerene thin film of the recording medium, moving the reading head in an approximately radial direction of the recording medium, positioning the reading head at a desired track of concentric tracks, and detecting the difference of current between a spot where the information is recorded and a spot where the information is not recorded with the reading head.

Assignees

• Showa Denko Kk

Inventors

• TONEGAWA Sho
• Ichikawa Masatoshi
• Hanawa Kenzo

Classifications

• G11B9/14

  using microscopic probe means {, i.e. recording or reproducing by means directly associated with the tip of a microscopic electrical probe as used in Scanning Tunneling Microscopy [STM] or Atomic Force Microscopy [AFM] for inducing physical or electrical perturbations in a recording medium; Record carriers or media specially adapted for such transducing of information (marking using electrical current B41M5/20; measuring roughness or irregularity of surfaces G01B7/34; details of scanning-probe microscopes G01Q)} · CPC title

• C01B32/156

  After-treatment · CPC title

• G11B9/04 Primary

  using record carriers having variable electric resistance; Record carriers therefor · CPC title

• G11B9/149

  characterised by the memorising material or structure · CPC title

• G11B5/851

  Coating a support with a magnetic layer by sputtering · CPC title