JP2001319387A - Recording/reproducing method, recording/reproducing head and recording/reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an eclipse of a laser beam due to a magnetic head and to enable surely applying the laser beam to the surface of a medium just under the magnetic head and heating the same. SOLUTION: This recording/reproducing head 100 is provided with the magnetic head 2 and an objective lens 7 on a slider 3. The objective lens 7 is disposed in such a manner that the light axis is inclined with respect to the surface of the magnetic recording medium 1. Thus, convergent light outgoing from the objective lens 7 is not intercepted by the magnetic head 2, but is made obliquely incident on the surface of the medium. Therefore, the laser beam can be surely applied on the surface of the medium just under the magnetic head 2. This recording/reproducing head 100 is suitable for a head following a magnetic recording/reproducing method of an optical assist type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording / reproducing a magnetic recording medium and a recording / reproducing head used therefor, and more particularly, to an optically assisted type recording / reproducing method capable of applying heat to a magnetic recording medium, The present invention relates to a recording / reproducing head and a recording / reproducing device.

[0002]

2. Description of the Related Art Magnetic disk devices are widely used as external storage devices for computers and the like. A recording / reproducing head mounted on a magnetic disk device has a structure in which a magnetic head is provided on a slider. The slider is supported by a suspension at the tip of a swingable arm, and has a structure that can be levitated by utilizing the flow of air when placed on a rotating recording medium. As magnetic heads for recording and reproducing information on and from a recording medium, small heads such as a thin film head and an MR (Magneto-Resistive) head are employed, respectively.

In recent years, a magnetic disk device has to handle an enormous amount of data such as voice information and image information in addition to character information in order to cope with multimedia. Is required. To increase the recording capacity of the magnetic disk drive, the recording surface density of the magnetic recording medium built in the magnetic disk drive may be increased. In order to improve the recording surface density of a magnetic recording medium, it is necessary to increase the coercive force of the recording layer in order to make the magnetization of the recording layer of the magnetic recording medium stably exist.

However, if the coercive force of the recording layer is increased, the magnetic field generated by the magnetic head must be increased by the increased coercive force when reversing the magnetization of the recording layer for recording information. However, in the current magnetic head, there is a limit to a magnetic field to be generated, and it has been difficult to write information on a magnetic recording medium in which a coercive force of a recording layer is increased in order to improve a recording surface density.

[0005]

As a method for solving this problem, an optically assisted magnetic recording / reproducing method has been proposed. In this method, at the time of information recording, information is recorded by heating the recording layer by light irradiation to temporarily lower the coercive force, and applying a magnetic field to a region where the coercive force is reduced. When reproducing recorded information, a leakage magnetic field from the recording layer is detected using a magnetic head equipped with a magnetoresistive element. In the optically assisted magnetic recording / reproducing method, even in a magnetic recording medium in which the coercive force of the recording layer is increased, the coercive force of the recording layer is reduced by heating by light irradiation during information recording. Has become possible.

A recording / reproducing head according to this method has a structure in which a magnetic head for recording / reproducing and a lens for condensing light are provided on a floating slider similar to a slider used in current magnetic disk devices. Have been. But,
When the magnetic head and the lens are mounted on the slider, the laser light converged by the lens may be blocked by the magnetic head, resulting in "shaking". As a result, the magnetic recording medium cannot be efficiently heated. In addition, it is difficult to arrange the magnetic head and the lens coaxially on the slider due to spatial restrictions due to the size of the lens. For this reason, on the magnetic recording medium, the position of the light spot formed by the lens cannot be brought close to the magnetic field application region formed by the magnetic head. Therefore, conventionally, an optical head having a lens mounted thereon and a magnetic head are arranged so as to face each other via a recording medium. A recording / reproducing head according to the optically assisted magnetic recording / reproducing method has not been put to practical use at present.

[0007] By the way, as an optical disk device, a device having an optical head equipped with a solid immersion lens is known. An optical head equipped with a solid immersion lens can form a minute spot on a medium. Therefore, in order to further increase the density, application of a solid immersion lens to the above-described optically assisted magnetic recording / reproducing method is being studied. In this case, it is necessary to mount a solid immersion lens on the floating slider and bring the solid immersion lens close to the recording medium.

The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent a laser beam irradiated for heating a recording medium from being blocked by a magnetic head, and to reliably prevent the recording medium from being damaged. An object of the present invention is to provide a recording / reproducing method capable of heating.

Another object of the present invention is to provide a recording / reproducing head capable of making the positions of a magnetic field application region and a heating region formed on a magnetic recording medium substantially coincide with each other, and a recording / reproducing apparatus having the same. .

[0010]

According to a first aspect of the present invention, in a recording / reproducing method for a magnetic recording medium, a laser beam is applied to a surface of the magnetic recording medium while applying a magnetic field to the magnetic recording medium. And recording information by making the light incident from an oblique direction.

According to the recording / reproducing method of the present invention, information is recorded by applying a magnetic field modulated according to recording information to a magnetic recording medium and irradiating a laser beam obliquely to the magnetic recording medium. In this way, the laser light is obliquely incident on the medium surface, thereby preventing the laser light from being blocked by the magnetic head when applying a magnetic field using, for example, a magnetic head, and heating the magnetic recording medium. The region can be reliably formed. Further, according to the recording / reproducing method of the present invention, even if the laser light irradiation and the magnetic field application are performed from the same side with respect to the magnetic recording medium, the heating area by the laser light irradiation and the magnetic field application by the magnetic field application are kept on the magnetic recording medium Since the areas can be easily matched, information can be reliably recorded on the magnetic recording medium. As used herein, the term “magnetic recording medium” includes a magnetic layer,
A magnetic recording medium in which information is provided to recording magnetic domains having different magnetization directions formed in the magnetic layer. For example, a magnetic disk that detects leakage magnetic field from a recording magnetic domain and reproduces information, or a magneto-optical effect. The concept includes a magneto-optical recording medium for reproducing information by utilizing the information and a recording medium for optically assisted recording and reproduction.

According to a second aspect of the present invention, in a recording / reproducing head for a magnetic recording medium, a recording magnetic head for applying a magnetic field to the magnetic recording medium and reproducing information recorded on the magnetic recording medium. And a recording / reproducing head comprising means for causing a laser beam to enter the surface of the magnetic recording medium obliquely.

Since the recording / reproducing head of the present invention includes means for making the laser light obliquely enter the surface of the magnetic recording medium, it is possible to prevent the laser light from being blocked by the magnetic head. Therefore, it is possible to efficiently irradiate the laser beam onto the magnetic recording medium, and it is possible to reliably form the heated area on the magnetic recording medium.

In the recording / reproducing head of the present invention, the means for injecting the laser beam obliquely to the surface of the magnetic recording medium may be, for example, such that the optical axis of the lens is oblique to the magnetic recording medium surface. It can be configured using the arranged objective lens. That is, in such a configuration, since the optical axis of the objective lens is obliquely oriented with respect to the surface of the magnetic recording medium, the laser beam converged by the objective lens is obliquely incident on the magnetic recording medium. In this case, it is desirable to arrange the objective lens and the recording magnetic head such that the optical axis of the objective lens and the center of the recording magnetic head are at the same position on the surface of the magnetic recording medium. This makes it possible to match the heating area formed on the medium by the laser light emitted from the objective lens with the magnetic field application area formed on the medium by the magnetic head.

Further, as another means for causing the laser beam to enter the surface of the magnetic recording medium obliquely, an objective lens whose optical axis is directed perpendicular to the surface of the magnetic recording medium may be used. it can. In this case, the objective lens is arranged such that the optical axis of the objective lens deviates from the optical axis of the laser light incident on the objective lens. In this way, by disposing the objective lens so that the optical axis of the objective lens does not coincide with the optical axis of the laser light incident on the objective lens, the center line of the convergent light emitted from the objective lens can be shifted to the magnetic recording medium. Can be directed obliquely with respect to the surface. That is, laser light can be incident on the surface of the magnetic recording medium from an oblique direction.

In the recording / reproducing head of the present invention, the recording magnetic head for applying a magnetic field to the magnetic recording medium includes:
For example, existing magnetic heads such as a ferrite magnetic head, a metal-in-gap (MIG) head, and a thin-film magnetic head can be used, and a thin-film magnetic head is particularly preferable. Such a thin-film magnetic head can make the head gap extremely narrow, so that a minute magnetic field can be formed on the magnetic recording medium to form a minute magnetic domain.

Further, in the recording / reproducing head of the present invention,
For a reproducing head for reproducing information, for example, a magneto-resistance effect element (MR element) or a giant magneto-resistance effect element (GMR element)
Element) can be used. These elements can reliably detect a leakage magnetic field generated from a minute magnetic domain. Such a reproducing head may be formed integrally with the recording magnetic head described above.

The recording / reproducing head of the present invention may include a slider that flies above the magnetic recording medium. On the slider, for example, a recording head, a reproducing head, an objective lens, and the like can be mounted. It is preferable that a light transmitting portion for transmitting convergent light from the objective lens is formed in the slider. The light transmitting portion may be configured using a material having a light transmitting property, or may be a through hole formed so as not to block light. Further, if the slider itself is made of a material having a light transmitting property, any position of the slider can be used as the light transmitting portion.

The recording / reproducing head according to the present invention may further include a solid immersion lens on the light path on the light emission side of the objective lens. By using a solid immersion lens, a minute spot can be formed on a magnetic recording medium, and a minute heating region can be formed. Therefore, minute recording marks can be recorded on the magnetic recording medium, and the storage capacity of the medium can be increased.

The recording / reproducing head of the present invention may include a laser light source for emitting the above-mentioned laser light.
Such a light source can be configured using, for example, a semiconductor laser light source.

According to a third aspect of the present invention, there is provided a recording / reproducing apparatus including the recording / reproducing head according to the second aspect and a magnetic recording medium.

The recording / reproducing apparatus of the present invention uses the recording / reproducing head according to the second aspect to apply a magnetic field modulated in accordance with recording information and to irradiate a laser beam obliquely to the surface of a magnetic recording medium. Since information can be recorded on a magnetic recording medium at a high density, it is suitable as a recording / reproducing apparatus according to an optically assisted magnetic recording / reproducing method. As the magnetic recording medium, a magnetic recording medium according to an optically assisted magnetic recording / reproducing method including a magnetic layer having a high coercive force can be used.As the magnetic layer, for example, even a magnetic layer having in-plane magnetization has perpendicular magnetization. It may be a magnetic layer having.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the recording / reproducing head according to the present invention will be specifically described, but the present invention is not limited thereto.

[0024]

Embodiment 1 FIG. 1 is a schematic sectional view in the longitudinal direction of a specific example of a recording / reproducing head according to the present invention. The recording / reproducing head 100 includes a magnetic head 2, an objective lens 7, and a reflection mirror 6 on a slider 3. The magnetic head 2 includes a thin film magnetic head (not shown) for applying a magnetic field to a magnetic recording medium when recording information, and an MR head (not shown) for detecting a magnetization state recorded on the magnetic recording medium. )
Are integrated magnetic heads. As the magnetic head 2, a magnetic head having the same configuration as a magnetic head conventionally used for a magnetic disk can be used.

In FIG. 1, a reflecting mirror 6 is supported by mirror holders 10a and 10b, and can reflect laser light from a laser light source (not shown) and make it incident on an objective lens 7.

The slider 3 is supported by a suspension 4 and can fly at a predetermined height from the surface of the rotating magnetic recording medium 1. A through hole 3a is formed in the slider 3, and the laser light converged by the objective lens 7 passes through the through hole 3a and is focused on the magnetic recording medium 1.

The objective lens 7 is held by a lens holder 8 provided on the slider 3 so that the optical axis of the objective lens 7 has a predetermined angle with respect to the bottom surface of the slider 3 (or the medium surface). Are located. The angle of the optical axis of the objective lens 7 is such that the optical axis of the objective lens 7 is
The magnetic head 2 is adjusted so as to intersect with a magnetic field applied region formed on the magnetic recording medium, that is, a magnetic recording medium located immediately below the magnetic head 2.

The recording / reproducing head 100 is, for example,
It is mounted on a recording / reproducing apparatus having a schematic configuration as shown in FIGS. FIG. 5 is a schematic configuration diagram of the top surface of the magnetic recording / reproducing apparatus, and FIG. 6 is a cross-sectional view in the AA ′ direction of FIG. In such a magnetic recording / reproducing apparatus, the recording / reproducing heads 100 are arranged on both sides (upper side and lower side) of the magnetic recording medium, and are controlled by a magnetic head drive system 54. The magnetic recording medium 1 is coaxially rotated by a spindle 52 of a rotary drive system 51. Further, as shown in FIG. 6, the recording / reproducing head 100 is disposed on both sides (upper side and lower side) of the magnetic recording medium 1, so that the irradiation of the laser beam and the application of the magnetic field are performed on both sides of the magnetic recording medium 1. The information can be recorded on both sides of the magnetic recording medium 1.

Next, recording and reproduction of information using the recording and reproduction head will be described with reference to FIG. During information recording, the recording / reproducing head 100 flies above the rotating magnetic recording medium 1 at a constant height. Laser light 5 emitted from a laser light source (not shown) is reflected by a reflecting mirror 6 and is incident on an objective lens 7, then is condensed by the objective lens 7 and is obliquely incident on the magnetic recording medium 1, 1 to form a light spot. As a result, a heating region at a predetermined temperature or higher based on the light intensity distribution is formed on the magnetic recording medium 1. Such a heating region is formed almost immediately below the magnetic head 2. Next, a magnetic field corresponding to the recording information is applied to the heated area by the thin film magnetic head of the magnetic head 2 to form a recording magnetic domain in the magnetic layer of the magnetic recording medium 1.

When reproducing information, the recording / reproducing head 100 is rotated by the rotating magnetic recording medium 1 as in the case of recording information.
Surface above. Then, the leakage magnetic field from the recording magnetic domain recorded on the magnetic layer of the magnetic recording medium 1 is applied to the MR of the magnetic head 2.
The information is reproduced by detection by the head.

[0031]

Second Embodiment FIG. 2 shows an improved example of the recording / reproducing head of the first embodiment. The recording / reproducing head 200 according to the present embodiment has a solid immersion lens 9 on the light path on the light emission side of the objective lens 7.
Except that the magnetic head 100 has the same structure as the magnetic head 100 of the first embodiment. In FIG. 2, the same parts as in the first embodiment
The description is omitted using the same reference numerals.

In FIG. 2, the solid immersion lens 9
Is a solid immersion lens processed into a quarter hemisphere, and is provided on the slider 3 adjacent to the magnetic head 2. When the laser light condensed by the objective lens is made incident on the solid immersion lens 9, evanescent light oozes out of the solid immersion lens, a minute light spot is formed on the magnetic recording medium, and a minute heating area is formed. Is done. Information is recorded by applying a magnetic field modulated according to recording information by the magnetic head 2 to such a minute heating area. The recording / reproducing head 200 equipped with the solid immersion lens 9 has a flying height from the surface of the magnetic recording medium of １ ／ of the wavelength of the laser light due to the optical limitation of the solid immersion lens 9 (the limitation on the propagation distance of the evanescent light). Need to be on the order.

[0033]

Third Embodiment FIG. 3 shows a schematic sectional view of another embodiment of the recording / reproducing head according to the present invention. Recording / playback head 300
In the recording / reproducing head according to the first embodiment, a rotationally asymmetric shape in which the optical axis is perpendicular to the medium surface is used instead of the objective lens in which the optical axis is inclined with respect to the medium surface. Of the objective lens 7 ′. In FIG. 3, the same portions as those of the recording / reproducing head of the first embodiment (see FIG. 1) are denoted by the same reference numerals, and description thereof is omitted.

In the recording / reproducing head shown in FIG. 3, the objective lens 7 'has a rotationally asymmetric shape in which an objective lens having a circular plane is cut in half by a plane including the optical axis. Are arranged in the vicinity of the central axis. Further, the angle of the reflection mirror is adjusted so that the optical axis of the laser light incident on the objective lens is shifted from the optical axis of the objective lens, and the objective lens 7 'is included in the light beam of the laser light incident on the objective lens 7'. So that the optical axis is not included
An objective lens 7 'and a reflection mirror are configured. Since the optical axis of the objective lens is near the center axis of the magnetic head, the laser light emitted from the objective lens is focused on a magnetic recording medium located almost immediately below the magnetic head 2 to form a heated area. Information is recorded by applying a magnetic field modulated according to the recording information by the magnetic head 2 to such a heated area.

[0035]

Fourth Embodiment FIG. 4 shows an improved example of the recording / reproducing head of the third embodiment. The recording / reproducing head 400 according to the present embodiment has the same structure as the recording / reproducing head according to the third embodiment except that the solid immersion lens 9 is provided on the light path on the light emission side of the objective lens 7 '.

The solid immersion lens 9 is a quadrangular spherical immersion lens similar to the solid immersion lens used in the second embodiment, and is provided on the slider 3 adjacent to the magnetic head 2. When the laser light condensed by the objective lens is made incident on the solid immersion lens 9, evanescent light oozes out of the solid immersion lens 9 and a minute light spot is formed on the magnetic recording medium. Thereby, a minute heating area is formed on the magnetic recording medium. Information can be recorded by applying a magnetic field modulated according to recording information by the magnetic head 2 to such a minute heating area.

Similarly to the recording / reproducing head of the second embodiment, the recording / reproducing head 400 according to the present embodiment also floats from the surface of the magnetic recording medium due to the optical limitation of the solid immersion lens 9 (restriction of the propagation distance of evanescent light). It is necessary to make the height about 1/4 of the wavelength of the laser light.

Although the recording / reproducing head according to the present invention has been specifically described with reference to the embodiments, the present invention is not limited to these embodiments.

For example, in the recording / reproducing head 100 of the first embodiment shown in FIG. 1, the mirror holders 10a and 10b and the lens holder 8 are connected to form a recording / reproducing head having a structure as shown in FIG. Can also. In the recording / reproducing head having such a structure, the mirror holders 10a and 10b can be used in place of the suspension, so that the suspension 4 holding the slider 3 in the recording / reproducing head of FIG. 1 becomes unnecessary. Further, in the recording / reproducing head of FIG. 8, the mirror holders 10a, 10b
Also, the mirror 6 can be integrally formed using a metal having a high light reflectance.

In the recording / reproducing head according to the third embodiment, the objective lens 7 'having a shape such that the objective lens having a circular plane is cut in half by the plane including the optical axis of the lens.
However, the objective lens 7 ″ having a circular plane as shown in FIG. 7 can be used as it is. In this case, the laser beam 5 is incident on the right side (or left side) of the objective lens 7 ″. I just need. In the case where laser light is incident from the left side of the objective lens 7 ", it is not necessary to form a light transmitting portion in the slider, so that the head configuration is simplified.

In the above embodiment, the information is recorded by irradiating the magnetic recording medium with a laser beam at the time of recording information. However, the irradiation of the magnetic recording medium is not limited to the recording of information. To heat the magnetic recording medium. In this case, the angle of incidence of the laser beam incident on the surface of the magnetic recording medium is adjusted so that a light spot (heating area) is formed on the magnetic recording medium located immediately below the reproducing magnetic head during information reproduction. Good. As a recording / reproducing head according to such a method, for example, FIG.
In the recording / reproducing head, the mirror holders 10a and 1
Instead of the reflecting mirror 6 fixed by Ob, a galvanometer mirror capable of appropriately adjusting the angle of the mirror may be used, and the angle of the galvanometer mirror may be finely adjusted during information recording and information reproduction. When the angle of the galvanomirror is finely adjusted, the angle of the laser light incident on the objective lens is changed, so that the position where the laser light is focused on the medium can be finely adjusted. At the time of information recording, the laser light is focused on the magnetic recording medium located immediately below the recording magnetic head, and at the time of information reproduction, the laser light is focused on the magnetic recording medium located immediately below the reproducing magnetic head. What is necessary is just to adjust the angle of the galvanomirror so that it may be performed.

[0042]

According to the recording / reproducing method of the present invention, a laser beam is obliquely incident on the surface of a magnetic recording medium. For example, when a magnetic field is applied to a magnetic recording medium using a magnetic head, the laser beam is Blocking by the head can be prevented.

According to the recording / reproducing head of the present invention,
As means for injecting laser light obliquely to the surface of the magnetic recording medium, for example, an objective lens arranged so that the optical axis of the lens is oriented obliquely to the surface of the magnetic recording medium is used. Even if the magnetic head and the objective lens are arranged on the same side with respect to the recording medium, the magnetic recording medium located immediately below the magnetic head can be reliably irradiated with laser light and heated. Therefore, the recording / reproducing head of the present invention is extremely effective as a recording / reproducing head according to the optically assisted magnetic recording / reproducing method. Further, by mounting such a recording / reproducing head on a recording / reproducing apparatus having a magnetic recording medium, it is possible to realize a magnetic recording / reproducing apparatus according to an optically assisted magnetic recording / reproducing method.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a specific example of a recording / reproducing head according to the present invention.

FIG. 2 is an improved example of the recording / reproducing head of FIG. 1, in which a solid-state immersion lens having a hemispherical shape is provided.

FIG. 3 is a schematic sectional view of another specific example of the recording / reproducing head according to the present invention, which is different from FIG.

FIG. 4 is an improved example of the recording / reproducing head of FIG. 3, which is provided with a quadrangular spherical immersion lens.

FIG. 5 is a schematic configuration diagram of an upper surface of the magnetic recording / reproducing apparatus.

6 is a schematic cross-sectional view in the AA ′ direction of the magnetic recording / reproducing apparatus of FIG.

FIG. 7 is a modified example of the recording / reproducing head shown in FIG. 3;

FIG. 8 is an improved example of the recording / reproducing head shown in FIG. 1,
This is a recording / reproducing head in which a mirror holder and a lens holder are connected.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Magnetic recording medium 2 Magnetic head 3 Slider 3a Through hole 4 Suspension 5 Laser beam 6 Reflection mirror 7, 7 ', 7 "Objective lens 8 Lens holder 9 Solid immersion lens 10a, 10b Mirror holder 100, 200, 300, 400, 700 Recording / playback head

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) G11B 7/135 G11B 7/135 Z A 11/105 551 11/105 551L 566 566B 571 571D (72) Inventor Harumi Sakamoto 1-88 Ushitora, Ibaraki-shi, Osaka Prefecture Hitachi Maxell Co., Ltd. (72) Inventor Kirino Fumiyoshi 1-88 Ushitora, Ibaraki-shi, Osaka Prefecture Hitachi Maxell Co., Ltd. (72) Norio Ota, inventor 1-88 Ushitora, Ibaraki-shi, Osaka Hitachi Maxell, Ltd. (72) Inventor Teruaki Takeuchi 1-88 Ushitora, Ibaraki-shi, Osaka F-term in Hitachi Maxell, Ltd. 5D034 BA02 5D075 AA03 CC01 CC11 CD17 CF03 5D090 AA01 CC01 CC04 KK09 LL01 5D091 AA08 CC30 DD03 5D119 AA21 BA01 EC26 JA44 JA57 LB05 MA06

Claims (20)

[Claims] 1. A recording / reproducing method for a magnetic recording medium, wherein information is recorded by applying a magnetic field to the magnetic recording medium and making a laser beam incident on a surface of the magnetic recording medium obliquely. Recording and playback method. 2. The information recorded on the magnetic recording medium,
2. The recording / reproducing method according to claim 1, wherein reproduction is performed using a magnetoresistive element. 3. The laser beam is converged using an objective lens, and the objective lens is arranged so that its optical axis is shifted from the optical axis of the laser light incident on the objective lens. The recording / reproducing method according to claim 1. 4. The recording / reproducing method according to claim 3, wherein a laser beam is incident on the objective lens so as not to include the optical axis of the objective lens. 5. The recording / reproducing method according to claim 3, wherein an objective lens having a rotationally asymmetric shape is used as the objective lens. 6. The method according to claim 1, wherein the laser beam is converged by using an objective lens, and the objective lens is arranged so that its optical axis is directed obliquely to the surface of the magnetic recording medium. 3. The recording / reproducing method according to 1 or 2. 7. The laser beam converged by the objective lens, which passes through a quarter-spherical solid immersion lens and is incident on a surface of the magnetic recording medium. Recording / reproducing method described in 1. 8. A recording / reproducing head for a magnetic recording medium, comprising: a recording magnetic head for applying a magnetic field to the magnetic recording medium; a reproducing head for reproducing information recorded on the magnetic recording medium; Means for making light obliquely incident on the surface of the magnetic recording medium. 9. A heating area is formed on the magnetic recording medium by the laser light incident on the magnetic recording medium by the means, and the recording magnetic head is arranged so as to be located above the heating area. The recording / reproducing head according to claim 8, wherein 10. The above-mentioned means is an objective lens for converging a laser beam, wherein the objective lens has an optical axis perpendicular to the surface of the magnetic recording medium and is a light beam of the laser beam incident on the objective lens. 10. The recording / reproducing head according to claim 8, wherein the recording / reproducing head is arranged so as to be shifted from the axis. 11. The recording medium according to claim 10, wherein an objective lens is disposed above the recording magnetic head so that an optical axis of the objective lens is located near the recording magnetic head. Recording / playback head. 12. The recording / reproducing head according to claim 10, wherein the objective lens is a rotationally asymmetric objective lens. 13. An objective lens for converging laser light, wherein the objective lens is arranged so that its optical axis is directed obliquely to the surface of the magnetic recording medium. The recording / reproducing head according to claim 8. 14. The object lens and the recording magnetic head, wherein the optical axis of the objective lens and the center of the recording magnetic head are arranged at the same position on the magnetic recording medium. Item 14. A recording / reproducing head according to Item 13. 15. The objective lens according to claim 10, further comprising a reflecting mirror on a light incident side of the objective lens, wherein the laser light reflected by the reflecting mirror is incident on the objective lens. The recording / reproducing head according to claim 1. 16. The recording / reproducing head according to claim 10, further comprising a hemispherical solid immersion lens on an optical path on a light emission side of the objective lens. 17. The recording / reproducing head according to claim 16, wherein the quadrangular solid immersion lens is provided close to a recording head. 18. The apparatus according to claim 10, further comprising a slider that floats on the magnetic recording medium, wherein the recording magnetic head, the reproducing head, and the objective lens are mounted on the slider. The recording / reproducing head according to any one of the preceding claims. 19. The apparatus according to claim 8, further comprising a laser light source for oscillating the laser light.
9. The recording / reproducing head according to any one of 8. 20. A recording / reproducing apparatus comprising: the recording / reproducing head according to claim 8; and a magnetic recording medium having a magnetic layer for recording information.