Electromagnetic field generating element,information recording and reproduction head, and information recording and reproduction device

• US 20090207702A1
• Filed: 01/29/2009
• Published: 08/20/2009
• Est. Priority Date: 01/30/2008
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Sato, Junichi, Eto, Hideki, Murakami, Yoshiteru
• Granted Patent: US 8,064,297 B2
• Time in Patent Office: Days
• US Class Current: 369/13.140
• CPC Class Codes: G11B 2005/0005 Arrangements, methods or circuits
• CPC Class Codes: G11B 2005/0021 Thermally assisted recording using an auxiliary energy source for heating the recording layer locally to assist the magnetization reversal
• CPC Class Codes: G11B 5/02 Recording, reproducing, or erasing methods; Read, write or erase circuits therefor
• CPC Class Codes: G11B 5/314 where the layers are extra layers normally not provided in the transducing structure, e.g. optical layers G11B5/3196 takes precedence

Abstract

An electromagnetic field generating element includes a conductor that generates near-field light when irradiated with light and generates a magnetic field when a current flows through the conductor. The electromagnetic field generating element further includes a soft magnetic body provided at a position along a dimension of the conductor, the dimension being perpendicular to (i) a direction in which the conductor faces a magnetic recording medium to which the near-field light and the magnetic field are applied and to (ii) a direction in which the current flows. The present invention thus allows for provision of an electromagnetic field generating element that allows for reduction in its power consumption in optically assisted magnetic read/write using near-field light.

Claims

1. An electromagnetic field generating element which causes (i) near-field light to be generated in a conductor in response to irradiation of the conductor with light and (ii) a magnetic field to be generated in response to a current flowing through the conductor, comprising:

a soft magnetic body provided in a direction perpendicular to a first direction in which the conductor faces an object to which the near-field light and the magnetic field are applied, and perpendicular to a second direction in which the current of the conductor flows.

2. The electromagnetic field generating element according to claim 1, wherein the conductor includes a constricted portion in which the near-field light is generated in response to the irradiation of the conductor with the light and the current is narrowed so that the current thus narrowed causes the magnetic field to be generated.

3. The electromagnetic field generating element according to claim 2, wherein:

the conductor has a groove section whose bottom portion constitutes the constricted portion, and

the groove section has a gap whose dimension in the second direction is shorter than a wavelength of the light.

4. The electromagnetic field generating element according to claim 1, wherein the soft magnetic body is a soft magneto-insulator.

5. The electromagnetic field generating element according to claim 1, wherein the soft magnetic body and the conductor are separated from each other.

6. The electromagnetic field generating element according to claim 5, wherein the soft magnetic body is provided in accordance with a linear velocity of the object.

7. The electromagnetic field generating element according to claim 1, wherein the soft magnetic body has a dimension of not less than 10 nm and not more than 1000 nm in the direction perpendicular to the first and second directions.

8. The electromagnetic field generating element according to claim 1, wherein the soft magnetic body has a first dimension in the first direction and a second dimension in the second direction, the first and second dimensions being different from each other.

9. The electromagnetic field generating element according to claim 8, wherein the soft magnetic body is shaped such that the first dimension is longer than the second dimension.

10. The electromagnetic field generating element according to claim 8, wherein the soft magnetic body is shaped such that the first dimension is shorter than the second dimension.

11. The electromagnetic field generating element according to claim 1, wherein the soft magnetic body has saturation magnetization of not less than 0.2 T and not more than 1 T.

12. The electromagnetic field generating element according to claim 1, wherein the soft magnetic body contains ferrite.

13. An information recording and reproduction head, comprising an electromagnetic field generating element,

said electromagnetic field generating element causing (i) near-field light to be generated in a conductor in response to irradiation of the conductor with light and (ii) a magnetic field to be generated in response to a current flowing through the conductor,

said electromagnetic field generating element comprising a soft magnetic body provided in a direction perpendicular to a first direction in which the conductor faces an object to which the near-field light and the magnetic field are applied, and perpendicular to a second direction in which the current of the conductor flows,

the object being a magnetic recording medium, and

said information recording and reproduction head further comprising a reproduction section for reproducing information which has been recorded on a target portion of the magnetic recording medium.

14. The information recording and reproduction head according to claim 13, wherein:

the reproduction section is a current measuring section for measuring a current flowing through the conductor; and

the information which has been recorded on the target portion of the magnetic recording medium is reproduced in accordance with a change in the current which flows the conductor and has been measured by the current measuring section.

15. An information recording and reproduction device comprising an information recording and reproduction head,

said information recording and reproduction head including an electromagnetic field generating element, said electromagnetic field generating element causing (i) near-field light to be generated in a conductor in response to irradiation of the conductor with light and (ii) a magnetic field to be generated in response to a current flowing through the conductor,

said electromagnetic field generating element comprising a soft magnetic body provided in a direction perpendicular to a first direction in which the conductor faces an object to which the near-field light and the magnetic field are applied, and perpendicular to a second direction in which the current of the conductor flows,

the object being a magnetic recording medium, and

said information recording and reproduction head further comprising a reproduction section for reproducing information which has been recorded on a target portion of the magnetic recording medium.