JPH04195747A - Magnetooptic recording medium - Google Patents

Abstract

PURPOSE:To improve adhesive properties and to eliminate a problem such as peeling of a film, etc., by forming a wear resistant protective film on a surface activated by electric discharging. CONSTITUTION:An optical pickup 2 and a magnetic head 3 are oppositely disposed through a magnetooptic disk 1, and a signal is recorded by sliding the head 3 on the disk 1. In the disk 1, a recording section 5 is laminated on one main surface of a board 4, and the section 5 is further covered sequentially with an ultraviolet ray curable resin layer 6 and a wear resistant protective film 7. Thus, the film 7 is formed on the sliding surface of the head. In this manner, durability against a wear, a damage, etc., is sufficiently obtained, and the film 7 is improved for wettability of the surface by electric discharging and then formed, and hence its adhesive strength is high, and a problem such as peeling, etc., does not occur.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magneto-optical recording medium used in a magneto-optical recording method in which recording is performed by sliding a magnetic head on the magneto-optical recording medium. be.

[Summary of the invention]

The present invention provides a magneto-optical recording medium in which a recording magnetic layer is formed on a transparent substrate, by subjecting the surface opposite to the transparent substrate to a discharge treatment and forming an abrasion-resistant protective film thereon. The objective is to improve the adhesion of the wear-resistant protective film and ensure sufficient durability even when the magnetic head is slid.

[Conventional technology]

In the magneto-optical recording method, the temperature of a part of a magnetic thin film is raised above the Curie point or temperature compensation point, and the coercive force in this part is extinguished to reverse the direction of magnetization in the direction of the externally applied recording magnetic field. The basic principle is that optical file systems, computer external storage devices, audio,
It is being put into practical use in video information recording devices and the like.

The magneto-optical recording medium used in this magneto-optical recording method consists of a recording magnetic layer (having an axis of easy magnetization perpendicular to the film surface and having a large magneto-optic effect) on the entire surface of a transparent substrate made of polycarbonate or the like. For example, a recording section is formed by laminating a rare earth-transition metal alloy amorphous thin film), a reflective layer, and a dielectric layer, and the signal is read by irradiating a laser beam from the transparent substrate side. It is being

[Problem to be solved by the invention]

By the way, magneto-optical recording methods can be broadly divided into optical modulation methods and magnetic field modulation methods, and because they can be overridden, expectations for the magnetic field modulation methods are increasing.

The above-mentioned magnetic field modulation method writes information signals in a magnetic thin film by reversing the applied magnetic field at high speed, and the application of the magnetic field is usually performed by a magnetic head having a magnetic field generating means.

In this case, a magnetic head that applies a high-speed switching magnetic field cannot generate a very small magnetic field due to various constraints, and it is necessary to move the magnetic head as close to the recording magnetic layer as possible. For example, in the case of a magneto-optical disk for data recording, the distance between the magneto-optical disk surface and the magnetic head is set to 0. Must be below II.

When the distance between the magneto-optical disk and the magnetic head is reduced in this way, it is necessary to improve the dimensional accuracy of the magneto-optical disk to suppress surface runout in order to prevent crashes of the magnetic head.

However, with magneto-optical disks made of substrates or polycarbonate, there is a limit to the suppression of surface runout, so a servo is applied to keep the distance between the magnetic head and the magneto-optical disk constant, such as the focus servo of an optical pickup. Or, like hard disks, a so-called flying head will have to be adopted.

On the other hand, especially in low-speed rotation systems of about 300 to 600 rpm, flying heads cannot be used and complex servos are required to control the distance.

Furthermore, in the case of a high-speed rotation system with a rotational speed of about 3600 rpm, it is possible to employ a flying head in which the magnetic head floats via an air bearing, but it is necessary to avoid the problem of crashes during start and stop.

Furthermore, even when using servo to maintain a constant distance from the disk, or when using a flying head, the distance between the magnetic head and the magneto-optical disk must be maintained. Also on the magneto-optical disk side, the recording magnetic layer must be a magnetic thin film that allows writing in a low magnetic field.

Therefore, a magneto-optical recording method has been considered in which recording is performed by sliding a magnetic head against a magneto-optical recording medium, but in this case, problems such as scratches and wear caused by the sliding of the magnetic head arise.

The present invention has been proposed to solve this problem, and an object of the present invention is to provide a magneto-optical recording medium that can ensure sufficient durability even when a magnetic head is slid.

[Means to solve the problem]

In order to achieve the above object, the magneto-optical recording medium of the present invention is a magneto-optical recording medium in which a recording magnetic layer is formed on a transparent substrate, in which the surface opposite to the transparent substrate is subjected to a discharge treatment, It is characterized in that a wear-resistant protective film is formed thereon.

[Effect]

When recording is performed while sliding the magnetic head across the magneto-optical recording medium, the distance to the recording magnetic layer becomes sufficiently small, and the magnetic field generated by the magnetic head can be small. Further, there is no need for a special side of the surfing machine for the magnetic head, and problems such as crashes are solved.

However, in this case, an increase in error rate due to wear and damage to the magneto-optical recording medium becomes a problem, but in the magneto-optical recording medium of the present invention, a wear-resistant protective film is formed on the sliding surface of the magnetic head. This ensures sufficient durability against wear and damage.

Furthermore, since the abrasion-resistant protective film is formed after improving the wettability of the surface by electric discharge treatment, the adhesive strength is high and problems such as peeling do not occur.

[Example] Hereinafter, an example to which the present invention is applied will be described in detail with reference to the drawings.

First, FIG. 1 shows a schematic configuration of a magneto-optical recording device for recording information signals on a magneto-optical disk according to this embodiment.
) between the optical pickup (2) and magnetic head (3).
are arranged facing each other, and signals are recorded while a magnetic head (3) is slid on the magneto-optical disk (1).

As shown in FIG. 2, the magneto-optical disk (1) of this embodiment used in such a recording device has a recording section (5) laminated on the -main surface of a substrate (4), and this recording section The surface of (5) is coated with ultraviolet curing resin layer (6) and wear-resistant protective film (7).
).

The substrate (4) is a disc-shaped transparent substrate with a thickness of several meters (for example, 1.2+u+), and its material includes acrylic resin, polycarbonate resin, polyolefin resin,
In addition to plastic materials such as epoxy resin, glass and the like are also used.

In addition, on the surface of this substrate (4) on the side where the recording section (5) is provided, there are usually guide grooves and addresses having a depth of about 1/4 of the wavelength of the laser light used during reproduction. Code pits and the like (all illustrations are omitted) are provided.

The recording section (5) includes a recording magnetic layer (8), a dielectric layer (9),
(10) and a reflective layer (11), and has a four-layer structure consisting of a substrate (4), a first dielectric layer (9), a recording magnetic layer (
8), the second dielectric layer (10), and the reflective layer (11).

Among these, oxides, nitrides, etc. can be used as the first dielectric layer (9) and the second dielectric layer (10), but in the dielectric layers (9) and (10), Nitride is more preferable because the oxygen in it may have an adverse effect on the recording magnetic layer (8), and silicon nitride, aluminum nitride, etc. are preferable as substances that do not allow oxygen and moisture to pass through and can sufficiently transmit the laser beam used. or suitable.

Further, the recording magnetic layer (8) is an amorphous magnetic thin film having an easy magnetization direction perpendicular to the film surface, and has not only excellent magneto-optical properties but also a large coercive force at room temperature. , and preferably have a Curie point near 200''C. Recording materials that meet these conditions include rare earth-transition metal alloy amorphous thin films, among which T
bFeC.

Amorphous thin films are preferred. This recording magnetic layer (8) may contain an additive element such as Cr for the purpose of improving corrosion resistance.

The reflective layer (11) is preferably composed of a film with a high reflectance that reflects 70% or more of the laser beam at the boundary with the second dielectric layer (1o), and is preferably a vapor-deposited film of a non-magnetic metal. be. Further, it is desirable that this reflective layer (11) is a good thermal conductor, and aluminum is suitable in consideration of ease of availability and ease of film formation.

Each of these layers is formed by a so-called vapor plating technique such as vapor deposition or sputtering. At this time, the thickness of each layer can be set arbitrarily, but it is usually set to about several hundred to several thousand. It is preferable that these film thicknesses be determined not only by the optical properties of each layer alone but also by taking into account the effects of the combination.

For example, when the thickness of the recording magnetic layer (8) is thinner than the wavelength of the laser beam, multiple interference occurs between the laser beam and the light that passes through the recording magnetic layer (8) and is reflected at the boundaries of each layer. This is because the effective optical and magneto-optical properties of the recording magnetic layer (8) vary greatly depending on the combination of thicknesses.

The ultraviolet curing resin layer (6) is provided for the purpose of flattening and protecting the surface of the recording section (5), but may be omitted depending on the case. The thickness of this ultraviolet curable resin layer (6) is about 3 to 5 μm, and acrylic ultraviolet curable resin or the like is usually used.

The above is the basic configuration of a magneto-optical disk (+),
In the magneto-optical recording medium of the present invention, since magnetic field modulation recording is performed while the magnetic head (3) is slid on the disk surface, the magnetic head (3) is placed on the ultraviolet curing resin layer (6) or on the recording section (5). A wear-resistant protective film (7) is provided directly on the magnetic head (3) to suppress wear caused by sliding and ensure running performance of the magnetic head (3). Below, this wear-resistant protective film (7
) will be explained.

First, the wear-resistant protective film (7) formed on the sliding surface of the magnetic head of the magneto-optical disk (1) is basically a resin-cured film made of thermosetting resin, electron beam curing resin, ultraviolet curing resin, etc. or a cured resin film containing a portion of an electron beam curing resin or an ultraviolet curing resin.

For example, by irradiating an electron beam-curable oligomer with an electron beam and curing it to form a wear-resistant protective film (7), a magneto-optical disk with less damage when brought into contact with a magnetic head can be obtained. In this case, the molecular weight of the oligomer used is 2
000 or less is preferable.

Similarly, a strong film can be formed by blending an ultraviolet curable resin into the wear-resistant protective film (7) and curing it by irradiating it with ultraviolet rays immediately after forming the protective film (7).

Alternatively, when forming the wear-resistant protective film (7), a curing agent may be added internally to improve the film strength and increase durability. In this case, the molecular structure and type of the curing agent used are arbitrary, and it is also possible to use multiple types of curing agents. The amount of curing agent added depends on the type of curing agent used, but it is usually 0.00 parts by weight per 100 parts by weight of the resin.
The amount is preferably 1 to 50 parts by weight. In addition, the curing temperature can be set arbitrarily, and curing at room temperature is possible, but since the curing speed is slow, it is possible to create a predetermined temperature environment (for example, above the glass transition point) in a constant temperature bath and place it there for a certain period of time to cure. It is preferable to increase the speed.

The heat curing treatment is advantageous not only in shortening the reaction time but also in terms of removing residual solvent and moisture, improving film hardness, and the like. As curing progresses and the curing agent becomes glassy, the film quality can be made harder and durability can be improved.

When the cured resin film is used as the abrasion-resistant protective film (7) as described above, suitable methods for forming it include a doctor blade method, a spin cord method, and the like.

For example, by placing the paint uniformly on the flat adapter between the doctor blade and the magneto-optical disk (1) and moving the doctor blade toward you, a coating film with a uniform thickness is formed. Alternatively, by attaching the magneto-optical disk (1) to the motor rotation shaft and supplying paint onto the magneto-optical disk (1) while rotating to form a coating film, a coating film with even thickness can be formed. . These methods not only facilitate film formation, but also ensure uniform film thickness.
Furthermore, by controlling the solid content and viscosity of the paint, it is possible to control the surface roughness and film thickness.

In addition, when mass production is considered, a gravure method, a sandblast transfer method, an offset method, etc. are also suitable.

In the gravure method, for example, a magneto-optical disk (1) is mounted on the outer peripheral surface of a disk holder with the magnetic head side surface facing outward, paint is supplied from a paint nozzle between an inkneri roll and a gravure roll, and the disc holder is By running the gravure roll while pressing it with a back roll, the paint on the surface of the gravure roll is transferred to the magnetic head side surface of the magneto-optical disk (1). When transferring paint, the thickness can be controlled by the position of the back roll and the pattern depth of the gravure roll. After the paint is transferred, it is flattened and dried with a dryer to form a paint film. Note that the back roll does not necessarily have to be cylindrical, and it is also possible to configure it so that the conveyor belt of the disc holder plays this role. 1. The position and rotation of the inkneri roll and the paint nozzle that supplies paint are arbitrary.

The sandblast transfer method transfers paint using a sandblast roll whose surface has been roughened by sandblasting, and the basic device configuration is the same as the gravure method described above. However, inkneri roll is not necessary,
Film thickness is controlled by the position of the back roll, peripheral speed of the sandblasting roll, and surface roughness.

The offset method has the same equipment configuration as the gravure method except that it uses an offset roll with a flat surface, and the film thickness is controlled by the position of the back roll, the circumferential speed of the offset roll, and the distance between the offset roll and the ink screw roll.

These methods are excellent in terms of uniformity of film thickness, ease of thickness control, reproducibility, and surface roughness, and the coating speed can be set to 100 m per minute or more, making it easy to mass-produce. This is very advantageous.

Of course, the wear-resistant protective film (7) is not limited to the above-mentioned cured film, for example, A11. Those made of wear-resistant materials such as Ni using methods such as plating, vapor deposition, and sputtering,
It may also be a coating of a lubricating polymeric material such as polytetrafluoroethylene or a non-woven fiber such as silk. Polytetrafluoroethylene is widely used as a solid lubricant, and methods for forming a film include directly rubbing it on the disk surface, vapor deposition, and spin-coding after dissolving it in a solvent. The non-woven fiber has a fiber diameter of 500
It is preferable to use fibers with a diameter of .mu.m or less, and the type of fibers may be natural or synthetic. Furthermore, it is also possible to use an abrasive-based nonmagnetic film or a lubricant film, and it is also possible to form the film by depositing lubricant powder. In this case, as the lubricant, any known lubricant such as fatty acids and fatty acid esters can be used, and the type and composition do not matter. As the lubricating powder, powder of a substance with a small coefficient of friction such as carbon or polytetrafluoroethylene may be used, or it is preferable that the hardness of the powder is lower than that of the substrate (4). The particle size of the lubricating powder used is approximately #8 to #200,000.

Moreover, the above-mentioned wear-resistant protective film (7) does not necessarily have to be a single layer, but can also be multilayered. In this case, by selecting the type of resin and the type of additives for each layer, it becomes possible to meet various demands. Alternatively, when the wear-resistant protective film (7) is made of a metal material, the lower layer is made of a hard metal film (or a non-metal film such as ceramics may be used), and the upper layer is made of Au, Ag, etc.
It is also possible to use a soft metal film such as Pb to reduce impact and friction.

Furthermore, a solid filler such as lubricating powder or abrasive material is added to the above-mentioned wear-resistant protective film (7) to improve running performance.

The durability may be further improved.

The type of lubricating powder and abrasive material does not matter, but carbon (carbon black, graphite powder, etc.) is the lubricating powder.
or polytetrafluoroethylene powder (so-called Teflon powder), etc., and alumina, chromium oxide (so-called green), etc. are suitable as the abrasive material. It is also possible to add multiple types at the same time.

The above-mentioned solid filler is generally added internally to the wear-resistant protective film (7), and in this case, the particle size is preferably within twice the film thickness at most. It is also possible to mix the solid filler with a small amount of binder or apply the solid filler alone to the surface of the wear-resistant protective film (7), in which case the maximum particle size is Protective film (7)
The film thickness shall be equal to or less than that of

Furthermore, lubricants, extreme pressure agents, coupling agents, etc., which are widely used in the field of magnetic recording media, etc., are added or applied to the wear-resistant protective film (7) to prevent damage when the magnetic head comes into contact with it. It may be possible to prevent this.

- All kinds of lubricants can be used, such as higher fatty acids such as oleic acid and fatty acid esters, and extreme pressure agents include phosphorus-based extreme pressure agents, sulfur-based extreme pressure agents, halogen-based extreme pressure agents, Any conventionally known ones such as a breeding metal extreme pressure agent or a composite extreme pressure agent can be used. As the coupling agent, various coupling agents such as a silane coupling agent, a titanium coupling agent, a zircoaluminate coupling agent, etc. can be used. By using these coupling agents, the resin constituting the wear-resistant protective film (7) and the substrate, as well as the powder components such as abrasives, are chemically bonded, increasing the strength of the film and its adhesion to the substrate. Is possible.

In addition, γ-FetOz acicular magnetic powder, Co-impregnated (doped) γ-FezCL acicular magnetic powder, Co-coated γ-FetOz acicular magnetic powder, metal magnetic powder, C
It is also possible to use magnetic powder such as rO or barium ferrite as the abrasive. Magnetic coatings containing these magnetic powders have been proven to have high durability when used with magnetic tapes, etc., and because of their high magnetic permeability, it is possible that even a small magnetic field can sufficiently apply a magnetic field to the recording section (5). There is.

When these magnetic powders are dispersed in the wear-resistant protective film (7), the orientation directions of the magnetic powders are non-oriented, circumferential direction (including cases where the magnetic powder is oriented obliquely to the film surface), and radial direction. (one direction within the plane), vertical direction, etc. are arbitrary, but
Various advantages can be obtained by selecting the orientation direction.

For example, in the case of non-oriented magnetic powder, the magnetic powder is oriented in random directions even at positions within the (+) plane of the magneto-optical disk.
The magnetic influence exerted on the recording magnetic layer (8) is considered to be the same regardless of the part, and the influence of pit length, noise, etc. is eliminated. Even when oriented in the circumferential direction, magneto-optical disks (
1) has the same orientation in any part of the recording magnetic layer (8
), there are few factors that give local magnetic anisotropy;
There is no change in bit length, noise, etc. depending on location.

On the other hand, in the case of perpendicular orientation, the magnetization direction of the recording magnetic layer (8) and the easy magnetization axis direction of the magnetic powder coincide, and since the magnetic permeability in this direction is high, a larger magnetic field is applied to the recording magnetic layer (8).
8), making it possible to record with a small magnetic field.

As the orientation method, any method used for magnetic recording media can be applied. For example, to achieve non-orientation, a pair of orientation magnet nodules may be used so that the opposing directions of the magnetic poles are perpendicular to each other within the film plane of the coating film. The alignment magnets may be arranged as shown in FIG. For orientation in the circumferential direction, use a long magnet with N and S poles on both sides in the width direction, and place one longitudinal end of this magnet at the center of the magneto-optical disk (1). , the magneto-soto may be rotated in the circumferential direction of the disk around this one end. In the case of orientation in the radial direction, both edges in the width direction or N
It is sufficient to use a long magnet with poles and south poles and move it parallel to the width direction of the magnet throat on the magneto-optical disk (1). In the case of vertical orientation, a magneto-optical disk (1)
The magneto-optical disk (1) may be rotated by arranging a DC magnet so that the magnetic flux passes perpendicularly to the disk surface.

In addition, by imparting color to the above-mentioned wear-resistant protective film (7) by selecting a pigment or the like, it is possible to ensure durability and, at the same time, to add design and increase C commercial value.

In the wear-resistant protective film (7) having the above configuration,
In order to perform good magnetic field modulation recording, it is necessary to set the film thickness to an appropriate value.

That is, the thickness of the wear-resistant protective film (7) determines the distance between the magnetic head (3) and the recording section (5). However, it is not necessary that the magnetic field be separated by a certain distance, but the minimum magnetic field necessary for recording must be within a range that reaches the recording magnetic layer (8) of the recording section (5). From the side of the magnetic head (3), the distance must be such that the recording current can be made sufficiently small to apply the same magnetic field to the recording magnetic layer (8). For example, in order to generate a magnetic field of ±200 Oe in the recording magnetic layer (8), the magnetic head (3) and the recording magnetic layer (
8) If the distance is 0.4 mm (400 μm), a recording current of approximately ±IA is required, whereas if the distance is 0.04 tm (40 μm), a recording current of approximately ±0.
A recording current of 5A is sufficient.

Regarding the lower limit, it is sufficient that the film thickness is sufficient to ensure durability, and the range is such that even if this wear-resistant protective film (7) is slightly scratched, it will not damage the recording section (5). do it.

In view of these points, the thickness of the wear-resistant protective film (7) is preferably 0.01 to 50 μm. If the film thickness exceeds 50 μm, the strength of the magnetic field reaching the recording magnetic layer (8) will be small, and a large recording current will be required during recording. On the other hand, if the film thickness is less than 0.01 μm, it will be difficult to ensure sufficient durability, and there is a risk that the recording section (5) will be damaged by scratches or the like.

By the way, when forming the above-mentioned wear-resistant protective film (7), if the wettability of the underlying magneto-optical disk surface (for example, the surface of the ultraviolet curable resin layer (6)) is poor, problems may arise in terms of adhesion. or remain. That is, the magneto-optical disk (1) of this example
In this case, the magnetic head (3) slides during recording, but if the adhesive strength of the wear-resistant protective film (7) is low, there is a risk that the magnetic head (3) may peel off when it comes into contact with the protective film (7). There is.

Therefore, in this example, the ultraviolet curing resin layer (6)
After the surface is subjected to electrical discharge treatment to improve surface wettability, a wear-resistant protective film (7) is formed to ensure the adhesive strength of the wear-resistant protective film (7).

In the discharge process, a ground electrode is placed opposite a discharge electrode connected to a high-voltage power supply, and a magneto-optical disk (
1) is carried out by placing the ultraviolet curing resin layer (6) so as to face the discharge electrode with a predetermined gap, and then applying a high voltage to the discharge electrode. When a high voltage is applied to the discharge electrode, plasma is generated due to gas discharge of the gas (air) existing between the discharge electrode and the ultraviolet curable resin layer (6), and positive ions are transferred to the ultraviolet curable resin layer (6).
released towards. These positive ions activate the surface of the ultraviolet curing resin layer (6) and clean it at the same time. After that, when a wear-resistant protective film (7) is formed, the adhesive strength of the wear-resistant protective film (7) is significantly improved.

Note that the voltage and current during the discharge process may be any voltage value or current value at which discharge is started, and the gap may be set to a distance that allows discharge to occur.

Further, the gas between the gaps is not limited to air, but may be any gas that can be ionized, and the shape of the discharge electrode is not limited as long as it can perform a good discharge.

Next, we actually created a magneto-optical disk, recorded data by sliding the magnetic head, and evaluated its characteristics.

The recording portion of the produced magneto-optical disk had a four-layer structure, and the film thickness was as follows.

First dielectric layer: Si, N, 1000 people Recording magnetic layer: Tb-Fe-Co-Cr230 people Second dielectric layer: 5iiNt 5oo people Reflective layer: A! ! 700 people Ultraviolet curing resin layer = 3 μm The above magneto-optical disk was placed on a ground electrode, and a voltage of 70 was applied in the atmosphere.
Discharge treatment was performed at 0V.

As a result, the contact angle of the surface of the ultraviolet curable resin layer with water increased from 80° to 60°, improving wettability.

Next, a wear-resistant protective film was formed on the discharge-treated ultraviolet curable resin layer by the following method.

Composition of paint Carbon (average particle size 200μ)...100 parts by weight Vinyl chloride-vinyl acetate copolymer...100 parts by weight Vinyl chloride-vinyl acetate-vinyl alcohol copolymer
...100 parts by weight of the above composition was kneaded in a ball mill for 40 hours with a mixed solvent of methyl ethyl ketone/toluene/cyclohexanone (1:1:1).

Next, 20 parts by weight of a thermosetting agent (trade name Coronate) and 1.5 parts by weight of an aliphatic hydrocarbon lubricant (olive oil) were added and stirred for 20 minutes.

This was applied onto the ultraviolet curable resin layer using a doctor blade with a gap of 25.4 μm and dried.

The thickness of the casing membrane after drying was 29 μm.

As a result, both adhesive strength and scratch tests showed that
Compared to the case without discharge treatment, the case of discharge treatment is better.
It has been found that significantly better results are obtained.

〔Effect of the invention〕

As is clear from the above explanation, in the magneto-optical recording medium of the present invention, since a wear-resistant protective film is formed on the surface, it is possible to significantly suppress wear caused by sliding of the magnetic head. Therefore, it is possible to ensure durability. Furthermore, since the wear-resistant protective film is formed on a surface activated by electrical discharge treatment, it can have excellent adhesion and solve problems such as film peeling. .

On the other hand, if the magneto-optical recording medium of the present invention is used, the distance between the magnetic head and the recording magnetic layer can be stably maintained at a small value without the need for complicated servos, etc. by sliding the magnetic head against the magneto-optical recording medium. can do. Therefore, a magnetic field modulation magnetic head can be used even if the generated magnetic field is small, and if it has the ability to generate a large magnetic field, it is possible to reduce the applied current and save power. . Furthermore, it becomes possible to ensure the frequency characteristics of the magnetic head up to a high frequency range, and it becomes possible to achieve high transfer rates and high density.

Also, when viewed from the magneto-optical recording medium side, it is no longer necessary for the recording magnetic layer to have high magnetic field sensitivity, and if the recording magnetic layer is a film that can be recorded in a low magnetic field, it is necessary to have a wide margin against the magnetic field. becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining a sliding type magneto-optical recording system to which the magneto-optical recording medium of the present invention is applied. FIG. 2 is an enlarged sectional view of a main part showing an example of the configuration of a magneto-optical recording medium to which the present invention is applied. 1... Magneto-optical disk 2... Optical pickup 3... Magnetic head 5... Recording section 7... Wear-resistant protective film

Claims (1)

[Claims] In a magneto-optical recording medium in which a recording magnetic layer is formed on a transparent substrate, the surface opposite to the transparent substrate is subjected to discharge treatment, and a wear-resistant protective film is formed on this. A magneto-optical recording medium characterized by: