JPH02227844A - Magneto-optical recording medium and magneto-optical recording/reproducing device - Google Patents

Abstract

PURPOSE:To prevent magnetism reverse area from being overlapped on that of adjacent tracks, and to prevent signal leakage due to the emission of reproducing laser beams on the magnetism reverse area of the adjacent track even when the interval between the tracks are narrowed by making an inter-track area on a magneto-optical recording layer into a non-perpendicularly magnetized film. CONSTITUTION:At least the recording part of the track area on a magneto- optical recording layer 2 is formed of a perpendicularly magnetized film 3 having an easy axis in a perpendicular direction, and at least an inter-track area 4 is formed of the non-perpendicularly magnetized film. In such a way the magnetism reverse area is not formed even when the inter-track area 4 is irradiated with the recording laser beams. Thus even when the interval between the tracks is narrowed, the magnetism reverse area is not overlapped on that of the adjacent tracks, or the signal leakage is not generated due to the emission of the laser beams on the magnetism reverse area of the adjacent track at the time of reproducing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a magneto-optical recording medium and a magneto-optical recording and reproducing apparatus that records and reproduces information using the same.

(Prior Art) Magneto-optical recording is attracting attention as a recording method that has a large capacity and allows writing. In magneto-optical recording, a recording medium is used in which a magnetic film with an easy axis of magnetization in the perpendicular direction (hereinafter referred to as perpendicular magnetization film), called a magneto-optical recording layer, is formed on a transparent substrate, for example. Sometimes a laser beam is focused onto the magneto-optical recording layer. Further, during recording, an external magnetic field that is sufficiently smaller than the coercive force of the recording layer at room temperature and reproduction temperature is applied to the laser beam focal point.

At this time, in the recording layer, only the region irradiated with the laser beam decreases in coercive force as the temperature rises until the recording temperature is reached, and the direction of magnetization is reversed to the direction of the external magnetic field. That is, information is recorded by controlling the medium temperature between a recording temperature and a non-recording temperature by power modulating the laser beam and reversing the magnetization direction of the magneto-optical recording layer. Further, the size of the magnetization reversal region formed on the recording medium depends on the temperature distribution accompanying the irradiation of the recording laser beam.

A magneto-optical recording medium is generally configured as a magneto-optical disk and has a track area formed in advance in a spiral or concentric shape, and information is recorded and reproduced according to the tracks.

When reproducing recorded information, the magneto-optical recording layer is irradiated with a reproducing laser beam with a power that does not reach the recording temperature, and reflected light from the medium is separated to obtain a reproduced signal. The reproduction laser beam is basically the same as the recording laser beam, and only the power is different. For this reason, the track spacing is set to be larger than the diameter of the laser beam (for example, about 1.3 μm) to reduce leakage (crosstalk) of information recorded on adjacent tracks (166
(about μm).

Therefore, if an attempt is made to improve recording density by narrowing the track spacing, the magnetization switching regions formed between adjacent tracks may overlap, or the laser beam may hit the magnetization switching regions formed on adjacent tracks during reproduction, causing the signal to be lost. leakage occurs, and the quality of the reproduced signal deteriorates.

By the way, in such a magneto-optical recording method, in order to rewrite already recorded information with new information, an operation called "erasing" is required to once align the magnetization direction of the recording layer to the state before recording. That is, the area to be rewritten is "erased" by irradiating the laser beam with an external magnetic field applied in the opposite direction to that during recording.

After that, it is necessary to perform "recording" by irradiating the same area with a laser beam while applying an external magnetic field in the same direction as during recording.

Therefore, it is theoretically difficult to overwrite information as is done in magnetic recording.

On the other hand, overwriting is possible using a method similar to magnetic recording in which the power of the laser beam is fixed to the same power as during recording and the direction of application of the external magnetic field is modulated at high speed. However, in order to modulate the magnetic field at a high frequency of several MHz, it is necessary to place the external magnetic field generating device close to the recording medium (for example, several μm to several μm), as in general magnetic recording. This impairs the interchangeability of the medium, which is one of the original advantages of magneto-optical recording.

As a method that allows information to be overwritten without impairing the interchangeability of the medium, a bias layer made of a perpendicular magnetization film similar to a magneto-optical recording layer is provided on the recording layer, and the bias layer is stacked on the recording layer. An external magnetic field generating device for aligning the magnetization direction is separately provided in the magnetic field application device, and the direction of magnetization formed in the bias layer is controlled by changing the power of the laser beam, and the magneto-optical recording layer is generated by exchange coupling force. A method of overwriting information by controlling the direction of magnetization has been proposed (Reference: T, NAKANOe).
t, al, INTERNATIONAL SYMPO
8IUM ON OPTICAL MEMORY 1
987JA3 (1987)), Ko (7) method, since it is not necessary to modulate both magnetic field generators, there is no need to place them close to the medium, and the exchangeability of the medium is ensured. However, in this method, in order to transfer the magnetization of the bias layer to the recording layer, the recording medium must have a structure that can control the exchange coupling force between the magneto-optical recording layer and the bias layer. In such a medium, the magnitude of the exchange coupling force varies significantly with changes in the amount of impurities and composition during film formation, so there is a problem that it is difficult to produce a stable medium with good reproducibility.

(Problems to be Solved by the Invention) As mentioned above, in conventional magneto-optical recording systems, when the track spacing is narrowed in order to increase the recording capacity, the magnetization reversal regions overlap between adjacent tracks, and the laser beams overlap during reproduction. There is a problem in that signal leakage occurs in the magnetization reversal region of the track, degrading the quality of the reproduced signal.

In addition, in conventional magneto-optical recording methods, when a method of modulating the external magnetic field at high speed for overwriting is used, the external magnetic field generator must be placed close to the medium, which impairs the interchangeability of the medium. Furthermore, the method of overwriting by providing a bias layer on the medium and controlling the magnetization direction of the magneto-optical recording layer by exchange coupling force has the problem that it lacks practicality because it cannot realize a medium with stable exchange coupling force. there were.

The first object of the present invention is to prevent the magnetization switching regions of adjacent tracks from overlapping even if the track spacing is narrowed, and the laser beam during reproduction from hitting the magnetization switching regions of adjacent tracks, thereby preventing signal leakage. The object of the present invention is to provide a magneto-optical recording medium from which high-quality reproduction signals can be obtained.

A second object of the present invention is to provide a magneto-optical recording medium and a magneto-optical recording/reproducing device that allow overwriting without impairing the exchangeability of the medium and are easy to manufacture. It is in.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the first object, the present invention provides at least the recording portion of the track area in the magneto-optical recording layer with a perpendicular magnetization film having an axis of easy magnetization in the perpendicular direction. By forming at least the inter-track region with a non-perpendicular magnetization film, leakage of signals between adjacent tracks is prevented.

Further, in order to achieve the second object, the present invention includes at least a magneto-optical recording layer on a substrate, a bias layer that supplies a bias magnetic field to the magneto-optical recording layer, and a gap between the magneto-optical recording layer and the bias layer. In a magneto-optical recording medium formed with a non-magnetic layer provided in The data can be erased using a magnetic field applied from the bias layer to the recording layer.

Furthermore, the magneto-optical recording and reproducing apparatus according to the present invention uses the latter magneto-optical recording medium, and includes a first magnetic field applying means for magnetizing the region of the perpendicularly magnetized film of the bias layer, and a heating means for heating the magneto-optical recording medium. and a second magnetic field applying means for applying a magnetic field to the magneto-optical recording medium at the same time as the heating by the heating means, and a second magnetic field applying means for applying a magnetic field to the magneto-optical recording medium at the same time as heating by the heating means, and a second magnetic field applying means for applying a magnetic field to the magneto-optical recording medium at the same time as the heating means. a first heating state in which the directions of the magnetic field are both aligned with the direction of magnetic field application by the second magnetic field applying means; and a bias magnetic field in which the direction of magnetization in the perpendicularly magnetized film region of the magneto-optical recording layer is applied from the bias layer. and a modulation means for modulating the heating means between a second heating state of heating to a temperature in a direction specified by .

(Function) If at least the inter-track region of the recording layer is made of a non-perpendicularly magnetized film, no magnetization reversal region will be formed even if the inter-track region is irradiated with a laser beam during recording, so the laser beam during reproduction will change the magnetization of adjacent tracks. It does not overlap the inversion region, and no signal leakage occurs.

Furthermore, if at least the inter-track region of the bias layer is made of a non-perpendicularly magnetized film, magnetization reversal or steep temperature gradient can be achieved even though the recording layer and bias layer are magnetostatically coupled via a non-magnetic layer. Even when cooling is not possible, a large bias magnetic field is applied from the bias layer to the recording layer.
Erase operation becomes possible.

Furthermore, by using a magneto-optical recording medium equipped with such a bias layer and a magneto-optical recording and reproducing apparatus comprising the above-described first magnetic field application means, heating means, second application means and modulation means, Overwriting is possible.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing a schematic configuration of a magneto-optical recording medium according to a first embodiment of the present invention. In the magneto-optical recording medium shown in the figure, a substrate 1 is a transparent substrate such as glass or transparent resin, and a magneto-optical recording layer 2 is formed thereon. This magneto-optical recording layer 2 is made of, for example, Tb, Fe, C.
It is formed from a thin film of an amorphous alloy such as O.

In this magneto-optical recording layer 2, a track area 3 for recording information is provided, for example, as a spiral or concentric land portion, and information is recorded and reproduced along the track area 3. On the other hand, an inter-track region 4 between the track regions 3 is formed as a group portion. The track region 3 of the magneto-optical recording layer 2 is a perpendicular magnetization film, and the inter-track region 4 is a non-perpendicular magnetization film.

FIG. 2 shows a schematic configuration of a magneto-optical recording and reproducing apparatus using the magneto-optical recording medium shown in FIG.
2, it is rotated at a predetermined speed. When recording information,
A laser beam modulated by a recording signal is emitted from the recording optical system 13, passes through a beam splitter 14, an objective lens 15, etc., and is irradiated onto the magneto-optical disk 11 from the substrate 1 side, where it is focused on the magneto-optical recording layer 2. .

An external magnetic field generator 16 is installed on the opposite side of the magneto-optical disk 11 from the objective lens 15 . This external magnetic field generating device 16 uses an electromagnet or a permanent magnet, and is configured to generate a constant magnetic field and apply it to the magneto-optical disk 11 at least during recording and erasing.

When reproducing information recorded on the magneto-optical disk 11, a laser beam with reduced power is similarly irradiated, and the reflected light from the magneto-optical recording layer 2 passes through the objective lens 15 in the opposite direction to the irradiated light. After being reflected by the beam splitter 14, the beam is incident on the reproduction optical system 17, thereby obtaining a reproduction signal.

Next, the effect of suppressing signal leakage according to the first embodiment will be explained. Figure 3 schematically shows the state on the surface of a magneto-optical recording medium when information is recorded with the track interval narrower than the laser beam spot diameter, for example.
) is when the magneto-optical recording medium shown in Figure 1 is used, (b) is -
This is a case where a conventional magneto-optical recording medium having a magneto-optical recording layer made of a perpendicularly magnetized film is used. In the case of FIG. 3(b), the magnetization reversal regions of adjacent tracks are close to each other and part of the spot of the reproduction laser beam is applied thereto, resulting in signal leakage.

On the other hand, in the case of FIG. 3(a) according to the present invention, since the inter-track region 4 is formed of a non-perpendicular magnetization film, even if the inter-track region 4 is irradiated with a recording laser beam, there is no magnetization reversal region. is not formed.

That is, the width (dimension in the direction across the track) of the magnetization reversal region can be limited. Therefore, although the track spacing is the same as in the case of FIG. 3(b), since the reproducing laser beam does not hit the magnetization reversal region of the adjacent track, no signal leakage occurs. As a result, for the same signal leakage tolerance, the track spacing can be changed from the conventional 1,
It becomes possible to narrow the width from 3 μm to about 1.0 μm or less, and the recording capacity can be significantly increased.

Next, an example of a method for manufacturing the magneto-optical recording medium shown in FIG. 1 will be described. First, after forming land portions and group portions in a spiral or concentric form on the substrate 1, a normal --like perpendicular magnetization film is formed, and the substrate 1 is mounted on the magneto-optical recording/reproducing apparatus shown in FIG. Prior to recording, it is rotated to make the laser beam follow the inter-track area 4. In this case, the tracking error may be detected by utilizing the difference in the amount of reflected light between the land portion, which is the track area 3, and the group portion, which is the inter-track area 4, and the irradiation position of the laser beam may be controlled based on the difference. However, in this case, the power of the laser beam should be higher than that during information recording and erasing, or the rotational speed of the disk should be lowered so that the relative movement speed (linear velocity) between the laser beam and the medium was lower than that during information recording and erasing. By setting the speed lower than that during erasing, the inter-track region 4 is heated to a temperature at which it changes to in-plane magnetization and crystallizes, thereby irreversibly losing perpendicular magnetization. As a result, the inter-track region 4 becomes a non-perpendicular magnetization film.

The first embodiment described above can be implemented with various modifications as follows.

In Fig. 1, the track area is a land part and the inter-track area is a group part, but conversely, the track area is a group part,
The inter-track area may be used as a land portion. Further, the present invention can be applied to a magneto-optical disk using a sample servo format without continuous groups.

In Figure 1, only the magneto-optical recording layer is formed on the substrate, but SiN and other layers are provided between and on the substrate and the magneto-optical recording layer for the purpose of adhesion, thermal effects, protection, etc. I don't mind.

In Figure 1, only the inter-track region of the magneto-optical recording layer is made with a non-perpendicular magnetization film, but a non-perpendicular magnetization film is also formed between the recording parts (recorded bit forming regions) in the track region using the same manufacturing method as above. This also reduces interference between adjacent bits within a track.

For example, if a dedicated device equipped with a short wavelength high-output laser device is used instead of using a magneto-optical recording/reproducing device for selectively forming a non-perpendicularly magnetized film, it is possible to form regions of a non-perpendicularly magnetized film with more precision. .

The form of the magneto-optical recording medium is not limited to a disk shape, but may be, for example, a tape shape.

Next, a second embodiment of the present invention will be described. Figure 4 is the second
1 is a cross-sectional view showing a schematic configuration of a magneto-optical recording medium according to an example. In the magneto-optical recording medium shown in the figure, the substrate 21
is a transparent substrate made of glass or transparent resin, for example, and a magneto-optical recording layer 22, a nonmagnetic layer 23, and a bias layer 24 are sequentially formed on this substrate. Magneto-optical recording layer 22
The bias layer 24 is formed of, for example, a thin film of an amorphous alloy such as Tb, Fe, Co, etc., and the nonmagnetic layer 23 as an intermediate layer is formed of, for example, SiN.

In the magneto-optical recording layer 22, the nonmagnetic layer 23, and the bias layer 24, a track region 25 is provided as, for example, a spiral or concentric land portion. On the other hand, an inter-track region 26 between the track regions 25 is formed as a group portion. Track regions 25 of the magneto-optical recording layer 22 and bias layer 24 are perpendicularly magnetized films, and inter-track regions 26 are non-perpendicularly magnetized films.

The nonmagnetic layer 23 is provided to prevent exchange coupling between the recording layer 22 and bias layer 24 and to ensure magnetostatic coupling between the two layers.

The structure of the magneto-optical recording and reproducing apparatus using the magneto-optical recording medium shown in FIG. 4 is basically the same as that shown in FIG. 2, but as shown in FIG. an external magnetic field generator 16a as a first magnetic field applying means for applying a magnetic field H1nIL for @magnetic field to the region; and a second magnetic field applying means for applying a recording magnetic field Hew to the focal point of the laser beam. An external magnetic field generator 16b is provided. These external magnetic field generating devices 16a and 16b are electromagnets or permanent magnets, and are configured to generate a single magnetic field and apply it to the magneto-optical recording medium at least during overwriting. The laser beam is irradiated from a laser light source which is heating means provided within the recording optical system 13 in FIG.

Next, the operation when overwriting is performed using the magneto-optical recording medium of this embodiment will be explained. FIG. 6 shows the coercive force temperature characteristics of the magneto-optical recording layer 22 and bias layer 24 in FIG.
Near a, the coercive force of the recording layer 22 is larger than the coercive force of the bias layer 24, and the Curie point TC of the bias layer 24 is
B is higher than the Curie point TCR of the recording layer 22.

Since the overwritten area of the magneto-optical disk passes under the influence of the external magnetic field H1nlt at room temperature Ta before being irradiated with the laser beam, the value of the magnetizing magnetic field H1nit is set to the recording layer 2.
By setting the coercive force between 2 and the coercive force of the bias layer 24 at room temperature Ta, only the magnetization of the bias layer 24 becomes H.
The recording layer 22 is magnetized and aligned in the lnit direction (upward in the figure), and the magnetization of the recording layer 22 retains the previously recorded information. The recording magnetic field Hex applied to the magneto-optical disk at the focal point of the laser beam is sufficiently smaller than the coercive force of the recording layer 22 and bias layer 24 at room temperature and reproduction temperature, and the direction of application is in the direction of H1nit. It is in the opposite direction (downward). Therefore, the information recorded in the recording layer is not destroyed when the laser beam is not irradiated or during reproduction. Below, recording layer 2
The operation of forming downward magnetization in the overwritten area of 2 is described as "
The explanation will be given by defining the operation of forming upward magnetization as "recording" and "erasing".

First, the recording process will be explained with reference to FIG.

(1) Before laser beam irradiation (temperature TmTa of the overwritten area) As shown in FIG. 7(a), the magnetization of the bias layer 24 is directed upward due to Hlnlt, and the magnetization of the recording layer 22 retains the previous information. The direction of magnetization is arbitrary (in FIGS. 7 and 8, the book represents that the direction of magnetization is arbitrary).

(2) During laser beam irradiation (T>T≧TCR) B As shown in FIG. 7(b), the magnetization of the recording layer 22 disappears at a temperature higher than the Curie point of the recording layer 22, and the bias layer 2
The magnetization of No. 4 remains upward.

(3) At the end of laser beam irradiation (T≧ToB) As shown in FIG. 7(C), the magnetization of the bias layer 24 also disappears at a temperature equal to or higher than the Curie point of the bias layer 24.

(4) After completion of laser beam irradiation Part 1 (T>T>TcR) B As shown in FIG. 7(d), the temperature of the bias layer 24 becomes below the Curie point, and downward magnetization is formed according to Hex.

(5) Part 2 after the end of laser beam irradiation (TcR>T≧Ta) As shown in FIG. A downward magnetization is formed according to the total value of the magnetic field tex. For example, if the medium is a magneto-optical disk and after returning to room temperature, it passes under the influence of the magnetizing magnetic field H1oll again, the magnetization of the bias layer returns to the upward direction, but the magnetization of the recording layer 22 remains downward. Because it is done,
There is no problem.

Next, the erasing process will be explained with reference to FIG.

(1) Before laser beam irradiation (T Ta) As shown in Figure 8 (a) K, the magnetization of the bias layer 24 is upward, the magnetization of the recording layer 22 retains the previously recorded information, and the direction is arbitrary. It becomes.

(2) At the end of laser beam irradiation (TcB>T≧”CR) As shown in FIG. 8(b), the magnetization of the recording layer 22 disappears at a temperature equal to or higher than the Curie point of the recording layer 22.

The magnetization of the bias layer 24 remains upward.

(3) After completion of laser beam irradiation (TcR>T≧Ta) As shown in FIG. 8(e), the temperature of the recording layer 22 becomes below the Curie point and magnetization is formed. The bias magnetic field applied from the bias layer 24 and the external recording magnetic field He
Although w works in the opposite direction, Hew can be made sufficiently small, so the magnetization that is formed will be directed upward.

As described above, in the recording process, the laser beam generation source serving as the heating means heats the medium temperature T to the Curie point TCB of the bias layer 24 or higher, and in the erasing process, the medium temperature T is heated to the Curie point TCB of the recording layer 22. Point “CR or higher (TCB
The direction of magnetization formed in the recording layer 22 is controlled by power modulating the laser beam so as to be modulated between these reheating states. However, here, the recording layer 22 and the bias layer 2
It was assumed that there was almost no difference in temperature between No. 4 and No. 4.

In the present invention, the magnetization of the recording layer 22 is controlled by a bias magnetic field generated due to magnetization formed in the bias layer 24. Here, if the recording layer and the bias layer are magnetostatically coupled and the bias layer is a --like perpendicularly magnetized film, then the 9th
As shown in Figure (b), in the erasing process where the bias layer does not undergo magnetization reversal, the bias magnetic field HB applied from the bias layer to the recording layer is
is small and in the opposite direction to the direction of magnetization of the bias layer, so erasing cannot be performed.

On the other hand, if the bias layer 24 of the track region 25 is made of a perpendicularly magnetized film and the inter-track region 26 is made of a non-perpendicularly magnetized film as in the present invention, as shown in FIG. A large bias magnetic field HB can be obtained even during cooling when a temperature gradient cannot be obtained. This is the inter-track region 26 around the track region 25 of the bias layer 24.
This is because the magnetization is a non-perpendicular magnetization film and has zero magnetization, so that the magnetization distribution centered on the track region 25 of the bias layer 24 becomes steep. As a result, even though the recording layer 22 and the bias layer 24 are magnetostatically coupled via the nonmagnetic layer 23, a large bias magnetic field HB is applied from the bias layer 24 to the recording layer 22. The magnetization can be aligned in a --like direction (the same direction as the magnetization of the bias layer 24), and erasing operation becomes possible.

Further, in the above embodiment, not only the bias layer 24 but also the recording layer 2
Also in Example 2, the track area 25 is a perpendicularly magnetized film and the inter-track area 26 is a non-perpendicularly magnetized film. ), and can be expected to have the effect of preventing signal leakage from adjacent tracks during playback.

Next, an example of a method for manufacturing a magneto-optical recording medium shown in the m4 diagram will be described. First, after forming land portions and group portions in a spiral or concentric form on a substrate 21, a first perpendicularly magnetized film that will become a normal --like recording layer 22, a non-magnetic layer 23, such as a SiN film, and a A second perpendicular magnetization film serving as a bias layer is sequentially laminated, the substrate 21 is mounted on the magneto-optical recording/reproducing apparatus shown in FIG. 2, and the medium is rotated prior to recording.
The laser beam is made to follow the inter-track area 26.

In this case, the tracking error may be detected by utilizing the difference in the amount of reflected light between the land portion, which is the track area 25, and the group portion, which is the inter-track area 26, and the irradiation position of the laser beam may be controlled based on the difference. However, in this case, the inter-track region 26 is transferred to in-plane magnetization and crystallized by using a laser beam with higher power than during information recording and erasing, or by lowering the rotational speed of the disk. Heating to a temperature that irreversibly causes perpendicular magnetization to be lost. As a result, the inter-track region 26 of the recording layer 22 and bias layer 24 becomes a non-perpendicular magnetization film.

Similarly to the first embodiment, the second embodiment described above can be implemented with various modifications. For example, in Fig. 4, the track area is the land part and the inter-track area is the group part.
Conversely, the track area may be used as a group part, and the inter-track area may be used as a land part.

Moreover, between the substrate and the magneto-optical recording layer and on the bias layer,
It is also possible to provide a layer of SiN or the like for the purpose of adhesion, thermal effect, optical effect, protection, etc. Further, the present invention can be applied to a magneto-optical disk using a sample servo format without continuous groups. In Fig. 4, the non-perpendicular magnetization film is used only in the inter-track area, but if a non-perpendicular magnetization film is also formed between the recording parts (recorded bit formation areas) in the track area, interference between adjacent bits within the track will be reduced. is also reduced. Instead of using a magneto-optical recording and reproducing device for selectively forming the non-perpendicular magnetization film, for example, a dedicated device equipped with a short wavelength high output laser device may be used, thereby forming regions of the non-perpendicular magnetization film more precisely. is possible. The form of the magneto-optical recording medium is not limited to a disk shape, but may be, for example, a tape shape.

Furthermore, in the second embodiment, as shown in FIG. 6, a case has been described in which neither the recording layer 22 nor the bias layer 24 has a compensation point at a temperature above room temperature Ta; In this case, the direction of magnetization formed during heating and the direction of magnetization after cooling are simply reversed. Therefore,
If the bias layer has a compensation point above room temperature, the same result as above can be obtained by simply setting the two types of external magnetic fields H5oil and Hex in the same direction.

[Effects of the Invention] According to the present invention, by forming at least the inter-track region of the magneto-optical recording layer into a non-perpendicular magnetization film, even when the track spacing is narrower than before in order to increase the recording capacity,
High-quality reproduction signals can be obtained without overlapping magnetization switching regions between adjacent tracks or causing signal leakage due to the reproducing laser beam entering the magnetization switching regions of adjacent tracks.

In addition, by forming at least the inter-track region of the bias layer into a non-perpendicularly magnetized film, the external magnetic field can be modulated at high speed while the recording layer and bias layer are magnetostatically coupled to produce a stable media structure. This method allows overwriting without sacrificing the interchangeability of the medium.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing the configuration of a magneto-optical recording medium according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram of a magneto-optical recording and reproducing apparatus using the magneto-optical recording medium of FIG. 1. FIG. 3 is a diagram for explaining the effect of preventing signal leakage between adjacent tracks in the same embodiment, and FIG. 4 is a schematic diagram showing the structure of a magneto-optical recording medium according to the second embodiment of the present invention. A diagram showing
Figure 5 is a diagram showing the main part configuration of a magneto-optical recording/reproducing device using the magneto-optical recording medium of Figure 4, and Figure 6 is the coercive force temperature of the recording layer and bias layer in the magneto-optical recording medium of Figure 4. A diagram showing the characteristics, FIG. 7 is a diagram for explaining the recording process in the same embodiment, FIG. 8 is a diagram for explaining the erasing process in the same embodiment, and FIG. 9 is a diagram for explaining the erasing process in the same embodiment. FIG. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Magneto-optical recording layer, 3... Track area (perpendicular magnetization film), 4... Inter-track area (non-perpendicular magnetization film), 11... Magneto-optical disk, 13 ...Recording optical system, 16...Magnetic field generator, 17...Reproducing optical system, 21...Substrate, 22...Magneto-optical recording layer, 23
. . . nonmagnetic layer, 24 . . . bias layer, 25 . . . track region (perpendicular magnetization film), 26 . Figure 1

Claims (3)

[Claims] (1) In a magneto-optical recording medium in which at least a magneto-optical recording layer is formed on a substrate, the magneto-optical recording layer is formed of a perpendicular magnetization film in which at least the recording portion of the track area has an axis of easy magnetization in the perpendicular direction, A magneto-optical recording medium characterized in that the intervening region is formed of a non-perpendicular magnetization film. (2) At least a magneto-optical recording layer, a bias layer that supplies a bias magnetic field to the magneto-optical recording layer, and a nonmagnetic layer provided between the magneto-optical recording layer and the bias layer are formed on the substrate. In the magneto-optical recording medium, at least the bias layer of the magneto-optical recording layer and the bias layer has at least the recording portion of the track area formed by a perpendicular magnetization film, and at least the inter-track area is formed by a non-perpendicular magnetization film. Features of magneto-optical recording media. (3) At least a magneto-optical recording layer, a bias layer that supplies a bias magnetic field to the magneto-optical recording layer, and a nonmagnetic layer provided between the magneto-optical recording layer and the bias layer are formed on the substrate. , a magneto-optical recording medium in which at least the recording portion of the track region of at least the bias layer of the magneto-optical recording layer and the bias layer is formed of a perpendicular magnetization film, and at least the inter-track region is formed of a non-perpendicular magnetization film; a first magnetic field applying means for magnetizing a region of the perpendicularly magnetized film of the bias layer; a heating means for heating the magneto-optical recording medium by irradiating the magneto-optical recording medium with a laser beam; A second magnetic field applying means for applying a magnetic field and a temperature at which the magnetization directions in the perpendicularly magnetized film regions of the magneto-optical recording layer and the bias layer are both aligned with the direction of magnetic field application by the second magnetic field applying means. The first heating the recording part of the recording medium.
and a second heating state of the recording section of the magneto-optical recording medium to a temperature such that the direction of magnetization in the perpendicularly magnetized film region of the magneto-optical recording layer is in the direction of the bias magnetic field applied from the bias layer. 1. A magneto-optical recording and reproducing apparatus comprising: means for modulating the heating means between heating states.