JPH03181043A - Optical/magnetic field conversion type magneto-optical disk, recording and reproducing method using the same, and magneto-optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To overwrite information only with irradiation of light without using a magnetic head by forming a light-magnetic field conversion layer having photosensitive ions in the vicinity of a magnetic recording medium layer on a substrate. CONSTITUTION:A light-magnetic field conversion layer 2 having photosensitive ions is formed in the vicinity of a magnetic recording medium layer 3 on a substrate 1 and is locally irradiated with circularly polarized light to generate a local magnetic field, and the direction of the generated magnetic field is switched by the rotation direction of the electric vector of this circularly polarized light to locally invert the magnetization direction of the magnetic recording medium layer 3. Consequently, the light is converted into the magnetic field by the action of photosensitive ions and information is recoded and erased by this magnetic field. Thus, information is overwritten only with an optical head without using the magnetic head.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rewritable optical/magnetic field conversion type magneto-optical disk, a method for recording and reproducing a magneto-optical disk using the same, and a magneto-optical recording and reproducing apparatus.

[Conventional technology]

Conventionally, magneto-optical recording methods are based on, for example, solid-state physics.

As described in Volume 23, No. 7 (1988), pages 494 to 500, information is recorded by irradiating the recording medium with light to locally raise the temperature, and when the coercive force decreases. , recording is performed by reversing the direction of magnetization in a local region using a relatively weak magnetic field applied from the outside. Therefore, when recording information, an optical head for emitting light and a magnetic head for applying an external magnetic field to reverse the direction of magnetization are required.

On the other hand, in order to reproduce recorded information, when a recording medium is irradiated with linearly polarized light through a polarizer, the polarization plane of the opposite or transmitted light rotates depending on the direction of magnetization, that is, the magneto-optic effect ( The magnetic Kerr effect in the case of reflection and the Faraday effect in the case of transmission are used to detect the direction of magnetization of the medium.

When magneto-optical recording is used as a computer file memory, it is necessary to be able to override it in order to reduce the apparently slow access time, but for this purpose it is essential to apply an external magnetic field. Become.

Note that override is called "overwriting" and is a method of directly rewriting what has already been written, unlike a method of erasing what has already been recorded and then rewriting it.

In order to provide this external magnetic field, an example using a magnetic head as described in the above-mentioned literature has been published.

As a recording medium, an amorphous perpendicularly magnetized film with low optical noise made of a magnetic alloy such as T b Fe Co is used, but since the Kerr rotation angle related to signal strength is small, it is necessary to improve the Kerr rotation angle by using a multilayer film. We are trying to However, it is still small at 0.5 degrees or less, and since the above medium has poor corrosion resistance, a protective film is required, and various protective films have been developed.

[Problem to be solved by the invention]

The above conventional technology is a thermal writing method in which the recording medium is locally heated by light irradiation and at the same time an external magnetic field is applied for recording. Linear speed is 12m/see, and in terms of disk device, it is 180O with a 5.25 inch disk.
rpm is the limit, and there is a problem in that the rotation waiting time is doubled compared to a magnetic disk (the rotation speed is usually 3600 rPm).

In addition, since the writing method is thermal writing, M n
Although it is a material that has a wide Kerr rotation angle (0.7 degrees) and can be expected to produce a large signal strength like B i, it is a material that causes an irreversible phase change when heated, so it is a rewriting method that involves heating. Not being used as a medium and Tb
Although they are chemically stable oxide media such as Fe0X and gadolinium iron garnet, they have a problem in that they cannot be heated and cannot be used because the material is transparent.

Furthermore, when a magnetic head is used to enable overriding, there is the problem of a fatal head crash when the magnetic head is flown in flight, which is the most important issue in improving the reliability of a magnetic disk.

The purpose of the present invention is to solve the above-mentioned conventional problems, and the first purpose is to provide an improved optical/magnetic field conversion type optical system that can record only by light irradiation without heating the recording medium. The second objective is to provide a recording and reproducing method for a magneto-optical disk that enables overwriting only by light irradiation without using a magnetic head, and the third objective is to provide a recording and reproducing apparatus using such a magneto-optical disk. The aim is to provide each of these.

[Means to solve the problem]

In order to achieve the above object, a light/magnetic field conversion layer having photosensitive ions is formed near the magnetic recording medium layer, and the light/magnetic field conversion layer is formed near the magnetic recording medium layer.
The magnetic field conversion layer is locally irradiated with circularly polarized light to generate a local magnetic field, and the direction of the generated magnetic field is switched depending on whether the electric vector of the circularly polarized light rotates clockwise or counterclockwise.
Recording is performed by locally reversing the direction of magnetization of the magnetic recording medium layer.

Further, in order to make the magnetic recording medium layer directly sensitive to light, the magnetic recording medium layer itself contains photosensitive ions.

Furthermore, in case the magnetic field generated by the optical/magnetic field conversion layer is insufficient to reverse the magnetization of the magnetic recording medium layer, a reinforcing magnetic layer is added to strengthen the magnetic field generated by the optical/magnetic field conversion layer. It is further established as follows.

Furthermore, in case the magnetic field generated by the optical/magnetic field conversion layer is insufficient to reverse the magnetization of the magnetic recording medium layer, the optical/magnetic field conversion layer is made of a ferromagnetic material having photosensitive ions.

Below, means for achieving each object of the present invention will be specifically explained.

The first purpose is to (1) form a magnetic recording medium layer on a substrate, and
Also, by a magneto-optical disk of optical/magnetic field conversion type, which comprises forming an optical/magnetic field conversion layer having photosensitive ions in close proximity to the magnetic recording medium layer.

(2) Forming a magnetic recording medium layer on the substrate, and
A light/magnetic field conversion type optical device in which a light/magnetic field conversion layer having photosensitive ions is formed adjacent to one surface of the magnetic recording medium layer, and a high magnetic permeability magnetic layer is formed adjacent to the other surface. This is achieved using magnetic disks. and.

(3) An optical/magnetic field converting type magneto-optical disk in which the optical/magnetic field converting layer of the optical/magnetic field converting type magneto-optical disk described in (1) or (2) above is composed of a ferromagnetic material having photosensitive ions. (4) This can also be achieved by an optical/magnetic field conversion type magneto-optical disk in which a magnetic recording medium layer is formed on a substrate and photosensitive ions are contained in the magnetic recording medium layer. Furthermore, preferably (5),
(1), (2), (3) or (4) wherein the photosensitive ion is composed of at least one element selected from the group consisting of Cs, Ba, La, Gd and Lu.
This is achieved by the optical/magnetic field conversion type magneto-optical disk described in ).

Also, the second purpose is as follows.

(6) Recording is performed by irradiating a magnetic recording medium layer formed on a substrate with light to reverse the magnetization direction, and detecting the direction of magnetization of this magnetic recording medium layer by Kerr or Faraday rotation of linearly polarized light. In the method for recording and reproducing a magneto-optical disk, the magneto-optical disk is subjected to the above (1).
, (2), (3) or (5), wherein the optical/magnetic field conversion layer is locally irradiated with circularly polarized light to generate a local magnetic field, Light that is recorded by locally reversing the direction of magnetization of the magnetic recording medium layer by switching the direction of the generated magnetic field depending on whether the electric vector of the circularly polarized light rotates clockwise or counterclockwise. Depending on the magnetic disk recording and playback method,
(7) Recording is performed by irradiating the magnetic recording medium layer formed on the substrate with light to reverse the magnetization direction, and the direction of magnetization of this magnetic recording medium layer is detected by Kerr or Faraday rotation of linearly polarized light. In the method for recording and reproducing a magneto-optical disk, the magneto-optical disk is subjected to the above (4).
Alternatively, the optical/magnetic field conversion type magneto-optical disk described in (5) is constructed, and the magnetic recording medium layer thereof is locally irradiated with circularly polarized light to generate localized light based on the photosensitive ions contained in the magnetic recording medium layer. Recording is performed by generating a magnetic field, switching the direction of the generated magnetic field depending on whether the electric vector of the circularly polarized light rotates clockwise or counterclockwise, and locally reversing the direction of magnetization of the magnetic recording medium layer. This is achieved by the magneto-optical disk recording and reproducing method as described above.

Furthermore, the third object is as follows: (8) A rotational drive control means for rotationally driving an optical/magnetic field conversion type magneto-optical disk; In a magneto-optical disk recording/reproducing apparatus comprising an optical head for recording and reproducing optical information by scanning and driving in a radial direction, and an actuator mounted with the optical head and scanning and driving, the magneto-optical disk is subjected to the above (1). , (2), (3), (4
) or (5), and the polarizer and quarter-wave plate that constitute the optical system of the optical head are arranged relative to each other with respect to the optical axis. This is achieved by a magneto-optical recording/reproducing device having means for switching the left and right rotation directions of circularly polarized light by rotating the circularly polarized light.

The magnetic recording medium layer used in the present invention is preferably a perpendicularly magnetized film, but any known perpendicularly magnetized film can be used. In addition, when reversing the direction of magnetization of the magnetic recording medium layer, circularly polarized light is irradiated in a constant rotation direction, but controlling the rotation direction (clockwise or counterclockwise) is done by directing the light emitted from the light source to a polarizer. When irradiating light through a quarter-wave plate, the positional relationship between the polarizer and the quarter-wave plate may be rotated relative to each other. Usually, it is practical and desirable to fix the position of the polarizer and rotate the 174-wave plate by 90' within the plane of the plate. Furthermore, a semiconductor laser is used as a light source, and even a small optical output of, for example, 5 mW or less, or about 1 mW, is sufficient for rewriting.

[Effect]

The photosensitive ions include, for example, Cs'', B a''L a
An ion such as 3+, ad3+, Lu3+, etc. whose ground state electronic configuration is in the S state, and which has a P state that can undergo a dipole transition upon excitation of approximately the energy of light.

The dipole transition law teaches that when an ion is irradiated with circularly polarized light, the orbital angular momentum is ±1, and the Z component of the orbital angular momentum (the quantization axis direction of the circularly polarized light, that is, the direction of the light traveling direction) component) is set to +1 or -1, respectively, depending on whether the circularly polarized light is clockwise or counterclockwise. Therefore, when an ion whose ground state is in the S state, which has no orbital angular momentum, is irradiated with circularly polarized light and transitioned to the P state, the Z component of the orbital angular momentum can be set to +1 or -1 depending on whether the ground state is clockwise or counterclockwise. I can do it. When the orbital angular momentum has a Z component, a magnetic moment of the magnitude multiplied by the negative Bohr magneton is generated. This magnetic moment generated by each ion in the circularly polarized light irradiation section generates a magnetic field to reverse the magnetization of the magnetic recording medium layer.

When such photosensitive ions are contained in a ferromagnetic material,
Due to the magnetic field generated by ions sensitive to circularly polarized light or direct interaction with transitioned electrons, the direction of magnetization of other surrounding spontaneously magnetized ions is aligned in the Z-axis direction, and the sensitive ions are The effect is that the magnetic field is strengthened.

〔Example〕

Embodiment 1 Hereinafter, one embodiment of the present invention will be explained with reference to FIG. This figure is a cross-sectional view of the main parts of a magneto-optical disk, and also shows a schematic diagram to explain the writing and reading methods. Shows how to read records. In the same figure, 1
2 is a transparent substrate, 2 is a light/magnetic field conversion layer, 21 is a direction of the magnetic moment generated in the light/magnetic field conversion layer, 22 is a magnetic flux created by the magnetic moment 21, 3 is a magnetic recording medium layer, 31 is a magnetic recording medium The direction of magnetization of layer 3 is shown.

In this example, glass was used as the transparent substrate 1, BaTi○□ containing Ba"+ as a photosensitive ion was used as the optical/magnetic field conversion WJ2, and MnBi (low temperature reduction) was used as the magnetic recording medium N93.

As a film forming method, a 200 nm BaTi 0° layer 2 is sputtered on a glass substrate 1, and M
A 200 nm thick n B i layer was formed by vacuum evaporation.

During recording, as shown on the left side of Figure 1, the optical/magnetic field conversion layer 2
Recording is performed by irradiating circularly polarized light (clockwise in this case) to generate a magnetic moment 21, and reversing the magnetization 31 of the magnetic recording medium layer 3 with the magnetic flux 22 created by the magnetic moment 21.

Note that when erasing a record, if the same location is irradiated with oppositely circularly polarized light (in this example, counterclockwise circularly polarized light), a magnetic moment in the opposite direction will be induced, the direction of the magnetic flux will be reversed, and the magnetic flux will be reversed. The data is erased by returning the magnetization direction of the recording medium N3 to its original state. In other words, it is an override and is erased at the same time as it is rewritten.

When reproducing a record, as in the case of conventional magneto-optical recording, linearly polarized light is incident as shown on the right side of the figure.
The direction of magnetization of the magnetic recording medium layer 3 is detected based on the direction of Kerr rotation of the reflected light.

In other words, the magnitude of the Kerr rotation θ is a physical constant specific to the material of the magnetic recording medium layer 3, and the larger the value, the S/
A magnetic recording medium layer with an excellent N ratio can be realized.

In this example, since it became possible to use M n Bi with excellent characteristics as the magnetic recording medium layer 3, the Kerr rotation angle was as large as 0.7 degrees, and readout detection with good S/H was possible. . Note that 1MnB1 is, as explained earlier,
Although it has excellent properties, it cannot be used in conventional recording methods that involve heating because the heating causes a phase change.

The light source used was a semiconductor laser with a wavelength of 780 nm, and the irradiation beam diameter was approximately 1-1.
The beam output at the time was 5 mW, and the readout beam output at the time of reproduction was 0.8 mW.

In this embodiment, a paramagnetic material N is provided between the optical/magnetic field converter N2 and the magnetic recording medium M3 to the extent that it does not interfere with the magnetic field.
Even if (150n+n) was provided, the effect was the same.

Example 2 The film structure of this example is exactly the same as that in FIG.
Magnetic field conversion/[2 as BaTi0. Barium ferrite Ba0.6Fe203 is used instead of H. The barium ferrite layer was formed by sputtering. Since the photosensitive ions Ba2+ are arranged in the barium ferrite ferromagnetic material /i12, the efficiency of generating a magnetic field when circularly polarized light is irradiated is high, and recording and erasing can be performed with lower optical energy. In this example, the beam power during override is 1mW.
was sufficient.

5 In this example, a paramagnetic material/@ is provided between the optical/magnetic field converter M2 and the magnetic recording medium layer 3 to the extent that it does not interfere with the magnetic field.
(50 nm), the effect was the same.

Embodiment 3 FIG. 2 is a cross-sectional view when a transparent magnetic recording medium M3 is used. A reflective film 4 is required to reflect linearly polarized light during readout. In the case of this example, the transparent substrate 1 is glass, and the light/magnetic field conversion layer 2 is B a T i O.
, , TbFe0. as the magnetic recording medium layer 3. , an Al vapor-deposited film was used as the reflective film 4. The film thickness of TbFeOx is 11
It was set to 00n. The film formation method was all sputtering. The rotation angle of the plane of linearly polarized light due to the Faraday effect during readout was 1.0 degrees. Furthermore, since the magnetic recording medium layer is an oxide, chemical stability is significantly improved.

The light source used was the same as in Example 1, and the wavelength was 7.
An 80 nm semiconductor laser was used, the irradiation beam diameter was approximately 14, the beam output during override was 5 mW, and the read beam output during reproduction was 0.8 mW.

As mentioned above, conventional recording methods require heating for recording, so even though this type of transparent magnetic recording medium layer has excellent Faraday effects, it cannot be used because it cannot be heated with light. be.

Example 4 The structure of this example is exactly the same as that in FIG. 2 of Example 3 above, but as the light/magnetic field conversion layer 2, Bar
j,oa/! Barium ferrite Ba0/6 instead of
It uses Fe,03. Since the photosensitive ions Ba'' are arranged in the barium ferrite ferromagnetic layer, the efficiency of generating a magnetic field when circularly polarized light is irradiated is high, and recording and erasing can be performed with lower optical energy.

In this example, as in Example 2, a beam output of 1 mW during override was sufficient. In contrast to the beam output intensity of 5 mW in Example 3, the beam output intensity of 1IIIW was sufficient, indicating that it is very effective to configure the optical/magnetic field converter N2 with a ferromagnetic layer containing this photosensitive ion.

Note that in this embodiment, a paramagnetic layer (to the extent that it does not interfere with the magnetic field) is provided between the optical/magnetic field converter M2 and the magnetic recording medium N3.
The effect was the same even if the thickness was 50 nm).

Embodiment 5 FIG. 3 is a cross-sectional view of the case where the magnetic recording medium layer 3 itself has photosensitive ions. In this case, the optical/magnetic field converting layer 2 is unnecessary. In this example, barium ferrite was used as the magnetic recording medium layer 3. Since the magnetic recording medium M3 itself contains photosensitive ions Ba''+, writing and erasing can be performed directly on the magnetic recording medium layer with light.

The light source used was overridden with the same laser beam as in the example, but the output intensity of the irradiation beam at this time was 1 mW, which was sufficient.

Embodiment 6 FIG. 4 shows a configuration in which the order of forming the films of the optical/magnetic field converter N2 and the recording medium 3 in Embodiment 3 is reversed.

In this case, a multiple interference effect occurred between the magnetic recording medium layer 3 and the reflective film 4, and the Faraday rotation angle was enhanced, and the rotation angle of the linearly polarized light plane due to the Faraday effect during reading was 1.2 degrees.

Example 7 FIG. 5 is a sectional view of the magnetic recording medium layer 3 of Example 1 in which a high magnetic permeability layer 5 is added to the back surface.

In the case of this example, a permalloy film formed by sputtering was used as the high magnetic permeability layer 5. As shown in the figure, the magnetic flux 22 generated in the light/magnetic field conversion layer 2 was absorbed with a high magnetic permeability of /15, and the magnetic field became stronger, so that efficient recording and erasing was possible. Moreover, the effect of this example is reflected/! in Example 3 and Example 6. If 4 is made of a high magnetic permeability material, exactly the same effect can be obtained.

Note that the light source used in this example was overwritten with the same laser beam as in Example 1, but the irradiation beam output intensity at this time was sufficient to be 1 mW.

Embodiment 8 FIG. 6 is a block diagram of an optical system used for recording and erasing information on the optical/magnetic field conversion type magneto-optical disk of the present invention. 6 is a light source, 7 is a polarizer, 8 is a quarter wavelength plate, 9 is a reflector, 1
0 is a lens, 11 is an optical/magnetic field conversion type magneto-optical disk, 1
2 is a rotary rotation motor.

Note that the configuration is such that the right-handed circularly polarized light and the left-handed circularly polarized light can be switched by rotating the quarter-wave plate 8 by 90 degrees within the plane of the plate.

FIG. 7 shows an outline of a magneto-optical recording and reproducing device 74 in the case where the optical head equipped with the optical system of the sixth embodiment is used to construct a magneto-optical recording and reproducing device.6 Features of this embodiment The optical head 71 is mounted on the actuator 72, and the heating head unlike the conventional one is not provided, and the configuration is simplified to only the optical system.

To explain the operating principle of this device, the optical/magnetic field conversion type magneto-optical disk 11 is rotated by a motor 73 controlled by a five-rotation control means.

An optical head 71 mounted on an actuator 72 in the radial direction of this rotating optical/magnetic field converting type magneto-optical disk 11 is scan-driven by a scanning control means, and in the case of writing in synchronization with this, a predetermined signal is emitted from the optical head 71. A writing laser beam having a certain beam intensity is irradiated onto a predetermined location of the optical/magnetic field conversion type magneto-optical disk 11 and recorded. On the other hand, in the case of reading, a read beam is irradiated to a predetermined location on the optical/magnetic field conversion type magneto-optical disk 11, and the reproduction beam reflected from the magneto-optical disk is used as optical information 75 to be sent to the optical head 7.
1, the signal is converted into an electrical signal and processed by necessary signal processing means.

Embodiment 9 FIG. 8 shows a block diagram of a case where a recording/reproducing apparatus using a magneto-optical disk of the optical/magnetic field conversion type of the present invention is used in a file memory of a computer.

Enables high-speed access and data transfer rate of 4MB
/sec was able to be achieved.

In all of the above embodiments, a transparent glass plate is used as the disk substrate, and irradiation light for recording and reproduction is introduced from the substrate side, but it may also be introduced from the opposite side to the substrate. Also 1
In the present invention, the substrate does not necessarily have to be a transparent plate, and may be composed of an opaque substrate. However, in such a case, the order in which the optical/magnetic field conversion layer 2, magnetic recording medium layer 3, reflective film 4, high magnetic permeability layer 5, etc. are formed may be changed according to the spirit of the present invention. Needless to say, it's a good thing.

〔Effect of the invention〕

According to the present invention, light can be converted into a magnetic field by the action of photosensitive ions, and recording and erasing can be performed using the magnetic field. Therefore, overriding can be achieved using only an optical head without using a magnetic head, and instead of using a conventional magnetic head. Countermeasures against head crashes become unnecessary.

Magneto-optical materials with good properties but no heat resistance, such as M n Bi, which could not be used in the past, or magneto-optical materials, such as T b
Transparent oxide magneto-optical materials with good chemical stability, such as FeOx, can now be used as the magnetic recording medium layer.

During recording, it is possible to wait for the temperature of the magnetic recording medium layer to rise, which has the effect of enabling high-speed recording and erasing of 1800 rpm or higher on the magnetic disk.

Furthermore, since the magnetic recording medium layer itself can contain photosensitive ions, the magnetic recording medium layer itself can function as a light/magnetic field conversion layer.

Further, by providing a high magnetic permeability layer, it is possible to strengthen the action of the magnetic field generated by the photosensitive ion beam, thereby enabling efficient recording and erasing.

Further, since a ferromagnetic material having photosensitive ions can be used for the light/magnetic field conversion layer, efficient recording and erasing power S can be achieved by an enhanced magnetic field.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the basic structure of a magneto-optical disk according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing another embodiment using a transparent recording medium, and FIG. , a cross-sectional view showing a different embodiment in which the magnetic recording medium layer itself has photosensitive ions, and FIG. 4 is a cross-sectional view showing a case where the order of the magnetic recording medium layer and the optical/magnetic field conversion layer is changed in FIG. FIG. 5 is a cross-sectional view showing an example of the structure when a high magnetic permeability layer is used. FIG. 6 is a cross-sectional view showing an example of the structure when a high magnetic permeability layer is used. FIG. FIG. 7 is a block diagram showing an optical system for generating circularly polarized light, FIG. 7 is an explanatory schematic diagram of a magneto-optical recording and reproducing device, and FIG. 8 is a block diagram showing an optical system for generating circularly polarized light. FIG. FIG. Explanation of symbols> 1...Transparent substrate 2...Light/magnetic field conversion layer 3.
...Magnetic recording medium layer 4...Reflection film 5...High magnetic permeability layer 6...Light source 7...Polarizer 8...
1/4 wavelength plate 9...reflector 10...lens l.
... Optical/magnetic field conversion type magneto-optical disk 12... Rotating motor 21... Magnetic moment induced in the light/magnetic field conversion layer 22... Formed by the magnetic moment induced in the light/magnetic field conversion layer Magnetic flux 31... Magnetization direction of magnetic recording medium layer 71... Optical head 72... Actuator 7
3... Motor 74... Magneto-optical recording/reproducing device 75... Optical information

Claims (1)

[Claims] 1. An optical/magnetic field conversion type comprising a magnetic recording medium layer formed on a substrate and an optical/magnetic field conversion layer having photosensitive ions in proximity to the magnetic recording medium layer. magneto-optical disk. 2. A magnetic recording medium layer is formed on the substrate, and a light/magnetic field conversion layer having photosensitive ions is formed adjacent to one surface of the magnetic recording medium layer, and a high magnetic permeability layer is formed adjacent to the other surface of the magnetic recording medium layer. An optical/magnetic field conversion type magneto-optical disk consisting of separate magnetic layers. 3. The optical/magnetic field conversion type magneto-optical disk according to claim 1 or 2, wherein the optical/magnetic field conversion layer is made of a ferromagnetic material having photosensitive ions. 4. Forming a magnetic recording medium layer on a substrate and containing photosensitive ions in the magnetic recording medium layer.
Magneto-optical disk with magnetic field conversion. 5. The light-magnetic field conversion type according to claim 1, 2, 3 or 4, wherein the photosensitive ion is composed of at least one element selected from the group consisting of Cs, Ba, La, Gd and Lu. magneto-optical disk. 6. Recording is performed by irradiating a magnetic recording medium layer formed on a substrate with light to reverse the magnetization direction, and reproduction is performed by detecting the direction of magnetization of this magnetic recording medium layer by Kerr or Faraday rotation of linearly polarized light. A method for recording and reproducing a magneto-optical disk according to claim 1, wherein the magneto-optical disk comprises:
3 or 5, the optical/magnetic field conversion layer is locally irradiated with circularly polarized light to generate a local magnetic field, and the direction of rotation of the electric vector of the circularly polarized light is A method for recording and reproducing a magneto-optical disk, in which recording is performed by locally reversing the direction of magnetization of the magnetic recording medium layer by switching the direction of a generated magnetic field depending on whether the magnetic field is clockwise or counterclockwise. 7. Recording is performed by irradiating a magnetic recording medium layer formed on a substrate with light to reverse the magnetization direction, and reproduction is performed by detecting the direction of magnetization of this magnetic recording medium layer by Kerr or Faraday rotation of linearly polarized light. In the method for recording and reproducing a magneto-optical disk, the magneto-optical disk is constituted by the optical/magnetic field conversion type magneto-optical disk according to claim 4 or 5, and the magnetic recording medium layer thereof is locally irradiated with circularly polarized light. A local magnetic field is generated based on photosensitive ions contained in the magnetic recording medium layer, and the direction of the generated magnetic field is switched depending on whether the electric vector of the circularly polarized light rotates clockwise or counterclockwise. A method for recording and reproducing a magneto-optical disk in which recording is performed by locally reversing the direction of magnetization of a recording medium layer. 8. A rotational drive control means for rotationally driving an optical/magnetic field conversion type magneto-optical disk, and recording optical information by scanning and driving the magneto-optical disk in the radial direction at a predetermined interval from the surface of the rotating magneto-optical disk. In a magneto-optical disk recording and reproducing apparatus comprising an optical head for reproducing and an actuator mounted on the optical head and driving the scan, the magneto-optical disk is exposed to the optical/magnetic field according to claim 1, 2, 3, 4 or 5. The optical head is configured with a conversion type magneto-optical disk, and by rotating the positional relationship between the polarizer and the quarter-wave plate that constitute the optical system of the optical head relative to the optical axis, the left and right polarized light can be changed. 1. A magneto-optical recording/reproducing device comprising means for switching the rotation direction of the magneto-optical recording/reproducing device.