Recording device and recording method

Patent metadata

Field	Value
Publication number	US-11574652-B2
Application number	US-202117401326-A
Country	US
Kind code	B2
Filing date	Aug 13, 2021
Priority date	Feb 13, 2019
Publication date	Feb 7, 2023
Grant date	Feb 7, 2023

Abstract

Provided is a recording device. The recording device includes: an external magnetic field application unit that is configured to apply an external magnetic field to a magnetic recording medium; a light irradiation unit that is configured to irradiate light; and a light focusing unit that is configured to focus the light from the light irradiation unit by resonating the light to generate an enhanced magnetic field in which a magnetic field of the light is enhanced, in which magnetization of the magnetic recording medium is inverted by applying the external magnetic field and the enhanced magnetic field to the magnetic recording medium.

First claim

The invention claimed is:

1. A recording device, comprising:
an external magnetic field application unit that is configured to apply an external magnetic field to a magnetic recording medium;
a light irradiation unit that is configured to irradiate light within a frequency band of 20 GHz to 1000 GHz; and
a light focusing unit that is configured to focus the light from the light irradiation unit by resonating the light to generate an enhanced magnetic field in which a magnetic field of the light is enhanced,
wherein magnetization of the magnetic recording medium is inverted by applying the external magnetic field and the enhanced magnetic field to the magnetic recording medium.

2. The recording device according to claim 1 ,
wherein the light focusing unit resonates the light at a resonance frequency at which natural resonance occurs in the magnetic recording medium, and generates the enhanced magnetic field in which the magnetic field is enhanced at the resonance frequency.

3. The recording device according to claim 1 ,
wherein the light focusing unit includes a side on which the enhanced magnetic field is generated, and the side is configured to be disposed within 200 nm from a recording surface of the magnetic recording medium.

4. The recording device according to claim 1 ,
wherein the light focusing unit includes a side on which the enhanced magnetic field is generated, the side includes a corner portion, and the corner portion is configured to be disposed to face the magnetic recording medium.

5. The recording device according to claim 1 ,
wherein the external magnetic field application unit includes a plurality of external magnetic field units configured to be disposed in line along a recording surface of the magnetic recording medium, and the magnetization of the magnetic recording medium is inverted by each of the plurality of external magnetic field units.

6. The recording device according to claim 1 ,
wherein the magnetic recording medium contains epsilon iron oxide particles on the recording surface.

7. The recording device according to claim 1 ,
wherein the light irradiation unit applies the light toward the light focusing unit without applying the light toward a region of the magnetic recording medium facing the light focusing unit.

8. The recording device according to claim 1 ,
wherein the light focusing unit is a ring-shaped light focusing ring including a gap.

9. The recording device according to claim 1 ,
wherein the light irradiation unit applies pulsed light as the light.

10. A recording method, comprising:
focusing light by resonating light within a frequency band of 20 GHz to 1000 GHz with a light focusing unit;
generating an enhanced magnetic field in which a magnetic field of the light is enhanced;
applying an external magnetic field from an external magnetic field application unit and the enhanced magnetic field to a magnetic recording medium; and
inverting magnetization of the magnetic recording medium.

11. The recording method according to claim 10 ,
wherein the light focusing unit is irradiated with the light after the external magnetic field is applied to the magnetic recording medium.

12. The recording method according to claim 10 ,
wherein the external magnetic field is applied to the magnetic recording medium after the light focusing unit is irradiated with the light.

13. The recording method according to claim 10 ,
wherein the magnetic recording medium contains epsilon iron oxide particles on a recording surface.

14. A recording device, comprising:
an external magnetic field application unit that is configured to apply an external magnetic field to a magnetic recording medium;
a light irradiation unit that is configured to irradiate light; and
a light focusing unit that is configured to focus light from the light irradiation unit by resonating the light to generate an enhanced magnetic field in which a magnetic field of the light is enhanced,
wherein magnetization of the magnetic recording medium is inverted by applying the external magnetic field and the enhanced magnetic field to the magnetic recording medium, and
the light focusing unit includes a side on which the enhanced magnetic field is generated, and the side is configured to be disposed within 200 nm from a recording surface of the magnetic recording medium.

15. The recording device according to claim 14 ,
wherein the light focusing unit resonates the light at a resonance frequency at which natural resonance occurs in the magnetic recording medium, and generates the enhanced magnetic field in which the magnetic field is enhanced at the resonance frequency.

16. The recording device according to claim 14 ,
wherein the light focusing unit includes a side on which the enhanced magnetic field is generated, the side includes a corner portion, and the corner portion is configured to be disposed to face the magnetic recording medium.

17. The recording device according to claim 14 ,
wherein the external magnetic field application unit includes a plurality of external magnetic field units configured to be disposed in line along a recording surface of the magnetic recording medium, and the magnetization of the magnetic recording medium is inverted by each of the plurality of external magnetic field units.

18. A recording method, comprising:
focusing light by resonating light with a light focusing unit;
generating an enhanced magnetic field in which a magnetic field of the light is enhanced;
applying an external magnetic field from an external magnetic field application unit and the enhanced magnetic field to a magnetic recording medium; and
inverting magnetization of the magnetic recording medium, wherein
the magnetic recording medium contains epsilon iron oxide particles on a recording surface.

19. The recording method according to claim 18 ,
wherein the light focusing unit is irradiated with the light after the external magnetic field is applied to the magnetic recording medium.

20. The recording method according to claim 18 ,
wherein the external magnetic field is applied to the magnetic recording medium after the light focusing unit is irradiated with the light.

Assignees

• Univ Tokyo
• Univ Osaka
• Fujifilm Corp

Inventors

• Ohkoshi Shin-Ichi
• YOSHIKIYO Marie
• Imoto Kenta
• Nakagawa Kosuke
• Namai Asuka
• Tokoro Hiroko
• Nakajima Makoto
• Shirata Masashi
• Naoi Kenji

Classifications

• G11B5/70642 Primary

  iron oxides · CPC title

• G11B5/706

  characterised by the composition of the magnetic material · CPC title

• G11B5/31

  using thin films {(G11B5/1274, G11B5/1278, G11B5/1874, G11B5/1875, G11B5/33, G11B5/49 take precedence; magnetic thin film structures H01F10/00)} · CPC title

• G11B5/02 Primary

  Recording, reproducing, or erasing methods; Read, write or erase circuits therefor · CPC title

• G11B2005/0021

  Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal · CPC title