JP2000315310A - Information recording medium and slider for recording and reproducing information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an information recording medium capable of stable existence of minute recording mark and recording and reproducing information even by using a conventional recording and reproducing device. SOLUTION: This information recording medium is provided with an information recording film consisting essentially of rare earth transition metal amorphous alloy capable of magnetically reproducing recorded information on a substrate. The information recording film 3 has 0.1-1.5 nm Ra or 10-40 nm projecting and recessing parts or is a switched connection multi-layered film. The film has essentially constant coercive force in a temperature range of from a room temperature to an, about 65 deg.C, >=55 Gauss μm product of residual magnetic flux density and film thickness and at least a rare earth transition metal amorphous alloy layer rich in transition metals and a rare earth transition metal amorphous alloy layer rich in rear earth metals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium and an information recording / reproducing slider. More specifically, the present invention relates to an information recording medium having improved recording / reproducing characteristics when information is magnetically recorded and reproduced, and an information recording / reproducing slider suitable for recording and reproducing information on and from the medium.

[0002]

2. Description of the Related Art As information recording media, optical recording media such as DVDs and magnetic recording media such as HDDs are known and widely used. Further, from the viewpoint that it is desired to increase the recording density of information, a magneto-optical recording (MO) medium combining the advantages of an optical recording medium and a magnetic recording medium has been studied.

According to an information reproducing method of magnetically detecting information recorded on magnetic materials of a magnetic recording medium and a magneto-optical recording medium among the above-mentioned recording media, as a result of research, recording is performed at an ultra-high density. Nowadays, the possibility of high-density recording exceeding 10 Gbit / (inch) ² has been shown. By the way, as the magnetic material, usually,
For example, Co ₇₇ Cr ₁₅ Pt having an easy axis of magnetization in the in-plane direction
Polycrystalline magnetic material such as ₆ Ta ₂ is used

Japanese Patent Application Laid-Open No. 58-165306 discloses an example in which a perpendicular magnetic film made of a rare earth transition metal amorphous alloy is used as a magnetic material of a magnetic recording medium. Further, this rare earth transition metal amorphous alloy is also used as a magnetic material of a magneto-optical recording medium,
In recent years, a magneto-optical recording medium having a laminate of a rare earth transition metal amorphous alloy film having different magnetic properties has been disclosed in
JP-A-217226, JP-A-5-325283, JP-A-63-302448 and the like.

[0005] Of these, in JP-A-63-302448, in particular, the rare earth metal (RE) in which the rare earth metal magnetic moment is larger than the transition metal magnetic moment is disclosed.
A magneto-optical recording medium having a laminate in which a rich film and a transition metal (TM) rich film in which a transition metal magnetic moment is larger than a rare earth metal moment is exchange-coupled is described.

More specifically, a TbFeCo film having a large Kerr rotation force is used for a TM-rich film, and a large signal level (ΔR · θ: R is a reflectance, θ is a Kerr rotation angle) is obtained for a RE-rich film. Using a TbFeCo film that can
A magneto-optical recording medium in which both films are exchange-coupled is described. In this medium, it is described that the increase in the nozzle level is suppressed so that a large SNR can be obtained and the writing energy can be reduced.
That is, when the medium described in this publication is used as a medium such as an MO, it is considered that recording noise can be reduced while obtaining a large magneto-optical effect.

[0007]

In order to further improve the recording density, it is necessary to further reduce the noise generated on the information recording medium. For that purpose, the particle size of the magnetic grains (crystal grains) must be about 10 nm. However, the polycrystalline magnetic material has a grain size of 10 n.
When the distance is set to about m, magnetic domains (recording bits) generated become thermally unstable, particularly at the interface between crystal grains. This in turn causes problems such as generating noise on the information recording medium and erasing the recorded information. In particular, such a reduction in the size of the magnetic grains causes a problem that the coercive force decreases with an increase in temperature (usually, the temperature in the drive during use becomes about 65 ° C.).

Further, the medium described in the above-mentioned JP-A-63-302448 is not suitable for a system for reproducing magnetic flux. For example, in Example 1 of the above publication, a magnetic film of Hc = 2 kOe (film thickness = 20 nm)
A medium composed of a laminated body with a magnetic film having a thickness of 10 kOe (film thickness = 60 nm) is described. However, the coercive force of this medium is much larger than the coercive force that can be recorded by a normal magnetic head. There is a problem that it is difficult to do. Further, the magnetization of the medium generally needs to be large enough to be detected by a magnetic head. In the case of the medium of the above publication,
The magnetic film of c = 2 kOe has relatively large magnetization, and Hc = 1
It is assumed that the 0 kOe magnetic film has relatively small magnetization.
The total magnetization is the sum of the magnetizations of the magnetic films constituting the medium.However, in the medium of the above publication, since the film having a large magnetization is thin, the total magnetization is very small and no magnetic flux is output to the outside. There is also a problem that detection is difficult.

[0009]

According to the present invention, Ra is 0.1 to 1.5 nm or the period is 10 to 40 n.
A first information recording medium comprising an information recording film mainly composed of an amorphous alloy of a rare earth transition metal capable of magnetically reproducing recorded information on a substrate having m irregularities is provided.

According to the present invention, there is further provided an information recording film comprising an exchange-coupling multilayer film capable of magnetically reproducing recorded information, wherein the exchange-coupling multilayer film is formed in a temperature range from room temperature to about 65 ° C. The coercive force does not substantially change, and 55 Gauss
having a residual magnetic flux density × film thickness product (tBr) of s μm or more;
A second information recording medium including at least a transition metal-rich rare earth transition metal amorphous alloy layer and a rare earth rich rare earth transition metal amorphous alloy layer is provided.

Further, according to the present invention, there is provided an information recording / reproducing slider used for recording and reproducing information on and from the information recording medium, wherein the light irradiating means, the recording head, and the magnetic element having the slider integrated therewith. An information recording / reproducing slider is provided, comprising a reproducing head, wherein the light irradiating means is positioned before the recording head and the magnetic reproducing head in the recording and reproducing directions of information.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first information recording medium according to the present invention will be described. In order to realize ultra-high-density recording by a method capable of magnetic recording / reproducing, the inventor of the present invention has proposed an amorphous alloy of a rare earth transition metal having a large magnetic anisotropy and no crystal grains to form an information recording medium film. We considered about using it. It is known that this amorphous alloy has a strong exchange coupling force inside the film. Therefore, it is considered that a recording head using a thin film coil used in a current recording / reproducing apparatus has a large head size and it is difficult to generate a sufficient magnetic field, so that it is difficult to form a minute recording mark. Have been. Further, it has been considered that the stability of the recording mark is deteriorated because the coercive force is reduced when the exchange coupling force is reduced. Therefore, it has not been common to use an amorphous alloy for an information recording medium.

However, the inventor has examined in detail the recording characteristics of an information recording medium using an amorphous alloy of a rare earth transition metal as an information recording film, the structure of the information recording film, and the like. It has been surprisingly found that, as shown in FIG. 1, an appropriate column structure is formed inside the magnetic film if appropriate unevenness is formed. In FIG. 1, 1 indicates a substrate, 2 indicates an underlayer, and 3 indicates an information recording film. Furthermore, it has been found that the information recording film having the column structure can form a minute recording mark even with a conventional magnetic head, and that a large reproduction signal can be obtained.

First, the information recording medium of the present invention comprises at least a base and an information recording film located thereon. As the substrate, any substrate known in the art can be used as long as irregularities having a predetermined Ra or period are formed. Specifically, examples of the substrate include a substrate made of glass, ceramics, titanium, silicon, carbon, or the like having irregularities, and a substrate having a base layer having irregularities formed on the substrate. When forming an underlayer,
A resin substrate such as polycarbonate can be used as the substrate.

As a method of forming irregularities on the substrate, the substrate is immersed in an acid such as hydrochloric acid, and polished with an abrasive having a predetermined particle size (eg, Al ₂ O ₃ , SiC, SiO). A so-called mechanochemical polishing method can be used. The unevenness of the underlayer may be formed simultaneously with the formation of the underlayer, or may be formed in another step after the formation of the underlayer. When the unevenness is formed simultaneously with the formation of the underlayer, it is necessary to select a material such that the unevenness on the surface of the layer becomes a predetermined shape as the layers are stacked, for example, by a sputtering method. Such materials include alloys such as NiP, NiB, CrMo, C
metals such as r and Ti. When the unevenness is performed in a step different from the formation of the underlayer, the material of the underlayer is not particularly limited.
In addition, as a method of forming irregularities on the underlayer, for example, a mechanochemical polishing method can be used. Among them, it is preferable to form the concavities and convexities simultaneously with the base layer in order to shorten the manufacturing process. In addition, Ni formed by the sputtering method
The P film has a feature that its particle size is small.

When NiP is used for the underlayer, its composition is not particularly limited. For example, a typical composition is N
There are i: P = 4: 1, 3: 1, 2: 1 and 5: 4. However, if the film is excessively rich in Ni, Ni
Is deposited, and the underlayer becomes a ferromagnetic material. In the case of a ferromagnetic material, there is a possibility that an electrostatic interaction occurs with the information recording film, thereby affecting the recording / reproducing magnetic field. Therefore, the composition of NiP is N
i: P = 4 to 2: 1 is preferable. In addition, CrMo generally has a Cr: Mo ratio of about 90:10.
The specific shape of the unevenness is Ra of 0.1 to 1.5 nm or a period of 10 to 40 nm.

Here, it is not preferable that Ra is smaller than 0.1 nm because a column structure is hardly formed in the information recording film. If Ra is larger than 1.5 nm, the size of one column becomes large and noise is likely to occur, which is not preferable. More preferred Ra is 0.2 to 1.2.
nm. Ra increases as the thickness of the underlayer increases,
It can be made smaller by making it thinner. In this specification, Ra is a value obtained based on JIS surface roughness (B0601). Specifically, a portion of the measurement length L is extracted from the roughness curve in the direction of the center line, the center line of the extracted portion is the X axis, the longitudinal magnification direction is the Y axis, and the roughness curve is y = f ( When expressed by x), it means a value obtained by the following equation expressed in nm.

[0018]

(Equation 1)

On the other hand, if the period is smaller than 10 nm, it is difficult to form a column structure, which is not preferable. Period 4
If it is larger than 0 nm, the column structure becomes large, which is not preferable. A more preferred period is 15 to 25 nm. The cycle can be controlled by adjusting the input power when the underlayer is formed by the sputtering method. The cycle increases as the input power increases and decreases as the input power decreases.
In addition, the thickness of the underlayer is preferably 7 to 75 nm. If the thickness is smaller than 7 nm, it is not preferable because a column structure is hardly formed. When the thickness is larger than 75 nm, the grain size of the column is too large, which is not preferable.

An information recording film mainly composed of an amorphous alloy of a rare earth transition metal capable of magnetically reproducing recorded information is formed on the substrate having the irregularities. Here, amorphous alloys of rare earth transition metals that can be used in the present invention include, for example, TbFe, TbFe
Cr, TbFeCo, DyFeCo, GdCo, GdF
e, TbCo, GdTbFe, GdTbFeCo, Gd
DyFeCo and the like. The compositions of these alloys are appropriately set so as to obtain desired coercive force and saturation magnetization. Among these alloys, TbCo, TbFe, TbFeC
r, TbFeCo and DyFeCo are preferred.

The thickness of the information recording film is preferably 20 to 50 nm. Furthermore, the information recording film of the present invention may be composed of two or more layers using magnetic exchange coupling between them. For example, in the case of two layers, a magnetization reversal auxiliary layer may be provided below the information recording film made of the amorphous alloy of the rare earth transition metal. By providing the magnetization reversal auxiliary layer, the recording mark can be stabilized. Further, a recording layer and a reproduction layer may be provided separately for recording and reproduction of information. By separating in this way, the composition of each film can be set so that the coercive force and the saturation magnetization are suitable for recording and reproduction.

The magnetization reversal auxiliary layer may be a perpendicular magnetization film or an in-plane magnetization film. As the perpendicular magnetization film, a crystalline alloy such as CoCrTa can be used in addition to the amorphous alloy. GdFeC as the in-plane magnetized film
o, GdFe and the like. The thickness of the magnetization reversal auxiliary layer is preferably from 2 to 10 nm. The above-mentioned amorphous alloy can be used for the recording layer and the reproducing layer.
As a specific combination, TbFe / TbFeC
o, TbFe / DyFeCo, TbCo / TbFeCo
And the like. The thickness of the recording layer and the thickness of the reproducing layer are 2
It is preferably 0 to 40 nm and 5 to 20 nm.
The method for forming the information recording film is not particularly limited, and any known method can be used. It is preferable to form by using a sputtering method among known methods.

The information recording medium of the present invention further comprises a substrate protective layer (eg, SiN, SiO) and a surface protective layer (eg, SiN
N, SiO), and a layer constituting a normal information recording medium, such as a carbon layer for improving the sliding property of the slider. The substrate protective layer is provided between the substrate and the information recording film (if the underlayer is present, between the underlayer and the information recording film).
The surface protective layer is generally located on the information recording film, and the carbon layer is generally located on the uppermost layer of the magnetic recording medium.

According to the information recording medium of the present invention, the SNR can be improved by 100% or more and the overwrite characteristics can be improved by 400% or more as compared with the case where no irregularities are formed on the substrate. This is considered to be because minute recording marks can be stably formed by the column structure inside the information recording film due to the unevenness of the base. Further, the information recording medium of the present invention can be used as a magnetic recording medium, and can also be used as a magneto-optical recording medium.

When the information recording medium of the present invention is used for a magneto-optical recording medium, information can be recorded with fine recording marks such as a track width of 0.1 to 2.5 μm and a width of a magnetization switching portion of 0.1 to 2 μm. Can be recorded, and this information can be reproduced by a known magnetic reproducing head.

Hereinafter, a second information recording medium of the present invention will be described. CoCr commonly used for information recording media
The coercive force of the in-plane magnetized film made of TaPt is 3 kO at room temperature.
e, but it drops to about 2.4 kOe at about 65 ° C. The coercive force of the perpendicular magnetization film made of CoCrPt is 3 kOe at room temperature, but drops to about 2.4 kOe at about 65 ° C. Therefore, it has been difficult to use these magnetic films stably at room temperature to about 65 ° C.

Therefore, the inventor of the present invention examined whether an information recording medium whose coercive force does not change with temperature can be obtained by using a rare earth transition metal amorphous alloy film. It is known that when the rare earth element is Tb or Dy in the rare earth transition metal amorphous alloy film, it has particularly large perpendicular magnetic anisotropy.

Specifically, when the alloy film is TbFe, FIG.
As shown in FIG. 7, when the composition of Tb is about 23%, there is a so-called compensation composition in which the value of the saturation magnetization becomes zero. In this specification, a region where Tb is higher than this compensating composition (that is, a region where the transition metal is low) is a rare earth (RE) rich,
A region where Tb is smaller than the compensating composition (that is, a region where the transition metal is large) is called transition metal (TM) rich. In FIG. 7, a indicates the range of perpendicular magnetic anisotropy, and b indicates the range of in-plane magnetic anisotropy.

Although FIG. 7 shows only the value of the saturation magnetization, the coercive force shows infinity in a composition in which the value of the saturation magnetization is minimum, and the coercive force decreases when the composition deviates therefrom. This phenomenon is the same even when the composition is replaced with temperature. In other words, the inventor of the present invention, the transition metal rich rare earth transition metal amorphous alloy layer, with the temperature rise,
The coercive force decreases, but the value of the saturation magnetization increases slightly.On the other hand, the rare-earth-rich rare earth transition metal amorphous alloy layer increases in coercive force with an increase in temperature, but the value of the saturation magnetization decreases. From the knowledge that the two are exchange-coupled, the coercive force and the saturation magnetization are kept almost constant in the temperature range from room temperature to around 65 ° C. by the exchange coupling multilayer film in which the saturation magnetization is set to a predetermined value. As a result, a second information recording medium capable of stably recording and reproducing information has been found.

First, as the rare earth transition metal amorphous alloy layer, for example, TbFe, TbFeCr, TbFe
Co, DyFeCo, GdCo, GdFe, TbCo,
GdTbFe, GdTbFeCo, GdDyFeCo and the like can be mentioned. Among these, at least Tb or D
It is preferable to include y. In particular, of these alloys, Tb
Co, TbFe, TbFeCr, TbFeCo, DyF
eCo is preferred.

The transition metal-rich rare earth transition metal amorphous alloy layer and the rare earth rich rare earth transition metal amorphous alloy layer can reproduce recorded information magnetically and can be maintained in a temperature range from room temperature to about 65 ° C. The composition and material are appropriately selected so that the magnetic force does not substantially change and the tBr is 55 Gauss μm or more. Specifically, as a combination of a transition metal rich rare earth transition metal amorphous alloy layer and a rare earth rich rare earth transition metal amorphous alloy layer, for example, in the case of Tb _x Co _1-x , 14 ≦ x ≦ 22 and 25 ≦ x ≦ 35 combinations (numerical values are mol%, the same applies hereinafter) For Tb _x Fe _1-x , a combination of 14 ≦ x ≦ 23 and 25 ≦ x ≦ 34 For Tb _x (FeCr) _1-x , 15 ≦ x ≦ 24 In the case of Tb _x (FeCo) _1-x , the combination of 14 ≦ x ≦ 23 and 25 ≦ x ≦ 34 In the case of Dy _x (FeCo) _1-x 16 ≦ x ≦ 22 and 24 ≦ Combinations of x ≦ 33 are mentioned.

The thicknesses of the transition metal rich rare earth transition metal amorphous alloy layer and the rare earth rich rare earth transition metal amorphous alloy layer are in the range of 5 to 45 nm and 5 to 45 nm, depending on the type of alloy layer used. Is preferred. The method for forming the alloy layer is not particularly limited, and any known method can be used. It is preferable to form by using a sputtering method among known methods. When tBr is smaller than 50 Gauss μm,
The SNR is reduced, making it difficult to record and reproduce information. A more preferred tBr is in the range of 57 to 135 Gauss μm.

The above two alloy layers are usually formed on a substrate. Here, either side of the transition metal rich rare earth transition metal amorphous alloy layer and the rare earth rich rare earth transition metal amorphous alloy layer may face the base.
As in the first information recording medium, a predetermined R
It is preferable that a or periodic irregularities are formed. A substrate that can be used specifically and a method of forming irregularities on the substrate are the same as those of the first information recording medium.

Further, as in the first information recording medium,
The magnetization reversal auxiliary layer is between the substrate and the alloy layer, the substrate protective layer is between the substrate and the alloy layer (if the magnetization reversal auxiliary layer is formed, between the exterior and the substrate), and the surface protective layer is the uppermost layer. It may be provided. Further, the second information recording medium of the present invention can be used as a magnetic recording medium as well as the first information recording medium, and can also be used as a magneto-optical recording medium.

When the first and second information recording media of the present invention are used as magnetic recording media, the recording and reproducing apparatus for recording and reproducing information on and from this medium is not particularly limited.
Any known device can be used. For example,
The information reproducing apparatus has at least a slider provided with a magnetic head. The magnetic head records and / or reproduces information on an information recording medium. Here, the magnetic head may include separate recording and reproducing heads, such as a recording head and a magnetic reproducing head. By using a thin film coil for a magnetic disk capable of high-speed transfer magnetic field reversal for the recording head, high-density recording can be performed without deteriorating the transfer rate.

When the first and second information recording media of the present invention are used as a magneto-optical recording medium, a recording / reproducing apparatus for recording / reproducing information on / from this medium includes, for example, a slider having a magnetic head, It has irradiation means. Here, the light irradiation unit irradiates the information recording medium with light, thereby raising the temperature of the irradiation unit, thereby facilitating recording and reproduction of information, and playing a role of further miniaturizing the recording mark. . As the light to be irradiated, for example, light generated from a laser is preferably used.

FIG. 2 shows an example of the configuration of a recording / reproducing apparatus having the above-mentioned light irradiation means. In the following, the light irradiating means will be described as a laser light irradiating means, but the present invention is not limited to laser light, and various lights can be used. In the figure, A is an information recording medium, 4 is a laser beam irradiation means, and 6 is a magnetic head unit including a slider.

When the light is laser light, the laser light irradiation means 4 includes a laser 41 for emitting laser light, a collimator lens 42 for converting the laser light into parallel light, a splitter 43 for transmitting or reflecting the laser light, and an objective lens 44. They are arranged in order toward the information recording medium A. Further, on the reflection side of the splitter 43, a half-wave plate 45 for rotating the deflecting surface of the laser light and a polarization beam splitter 46 for separating the laser light into a horizontal component and a vertical component are arranged in this order. At the output side of the splitter 43, condensing lenses 47 and 49 for condensing the output light of the horizontal component and the vertical component respectively are arranged.
0 are respectively arranged. The photodetectors 48 and 50 are connected to an amplifier 51 which obtains a difference between detection signals obtained therefrom and amplifies the difference, so that a signal from the amplifier 51 is output to a switching terminal 65 of a switch unit. Has become.

The magnetic head unit 6 receives an electric signal corresponding to the magnetization direction detected by the slider 61 having the magnetic head and inputs the amplified signal. The amplified circuit 62 receives the amplified signal and shapes the waveform. Is provided. The signal from the integrating circuit 63 is output to the switching terminal 66. Either of the signals output to the switching terminals 65 and 66 is input to the demodulation circuit 64 by switching the common terminal 67 of the switch unit, and is demodulated and output as a signal.

According to the recording / reproducing apparatus shown in FIG. 2, the information recording medium A is irradiated with laser light from the laser light irradiating means 4 to raise the temperature of the irradiating portion so that information can be easily recorded and / or reproduced. Then, information can be recorded and / or reproduced with the magnetic head in the region where the temperature has increased. FIG. 3 shows a conceptual diagram of recording and / or reproduction of this information. In FIG.
Reference numeral 11 denotes a temperature rising area, 12 denotes a magnetic head, and 13 denotes a track pitch. Specifically, by irradiating a laser beam during recording, the coercive force of the information recording film is reduced,
The recording current can be reduced. Furthermore, it is possible to record on a medium having a large coercive force at room temperature. On the other hand, by irradiating a laser beam during reproduction, the value of the magnetization of the information recording film is increased, and the reproduction signal can be increased.

Further, according to the present invention, there is provided an information recording / reproducing slider used for recording and / or reproducing information on a magneto-optical recording medium, wherein the slider is integrated with a laser beam irradiating means, a recording head and a recording head. Equipped with a magnetic reproducing head,
There is also provided an information recording / reproducing slider in which the laser light irradiating means is located before the recording head and the magnetic reproducing head in the recording and reproducing directions of the information.

The slider has, for example, a configuration as shown in FIG. In FIG. 4, 21 is a slider, 22 is a slider supporting means (for example, a spring), and 23 is a laser beam irradiation means (for example, an optical fiber). FIGS. 5 and 6 are cross-sectional views of the main part of the slider. 5 and 6, 3
1 is a recording head, 32 is a magnetic reproducing head, and 33 is a laser beam irradiation means. FIGS. 5 and 6 show that the laser beam irradiation means, the recording head and the magnetic reproducing head are integrated, and that the laser is positioned before the recording head and the magnetic reproducing head in the information recording and reproducing direction (the direction of the arrow in the figure). Light irradiation means is located. This is because the increased temperature distribution flows backward, so that the recording and / or reproduction of information can be performed efficiently by arranging the recording head and the magnetic reproducing head behind the laser beam irradiation means. is there. In addition, since they are integrated, a high-speed seek can be performed as compared with a conventional apparatus in which a laser beam irradiation unit is separated. 5 and 6 differ in the arrangement of the recording head and the magnetic reproducing head. Also, to prevent the recording head and magnetic reproducing head from deteriorating from the temperature rise by the laser beam,
The heat radiation layer may be provided on the lower surface (media side) of the slider. It is preferable to use a heat radiation layer having good heat conductivity, such as aluminum or copper.

In the recording / reproducing apparatus, as a laser beam irradiation means, for example, LiNbO _{3 is formed} on an AlTiC substrate.
Is formed as a core, an optical waveguide having a cladding of SiO ₂ -based glass is formed, and a recording head and a magnetic reproducing head are formed thereon by a known means.

[0044]

EXAMPLES Next, specific embodiments of the present invention will be described with reference to examples, but the present invention is not limited by these examples. (Example 1) A glass substrate having Ra <0.05 nm (hereinafter, referred to as a glass substrate)
The film thickness is set to 0 to 1.
Underlayer made of Ni ₃ P varied between 5 nm, 2n
m, a substrate protection layer made of SiNx, an information recording film (magnetic film) made of 50 nm amorphous alloy Tb ₁₅ Fe _85, a surface protection layer made of 3 nm SiNx, and
An information recording medium was formed by laminating a 3 nm C (carbon) layer for improving the slipperiness of the reproducing head by sputtering in this order. Specifically, each layer was formed under the following conditions.

Magnetic film—sputter gas: Ar Sputter gas pressure: 0.5 Pa Input power: 1 kW Underlayer—sputter gas: Ar Sputter gas pressure: 2 Pa Input power: 1 kW Substrate protective layer and surface protective layer—sputter gas: Ar and N ₂ (gas mixture ratio Ar / N ₂ = 7/3) Sputter gas pressure: 0.3 Pa Input power: 0.8 kW C layer-sputter gas: Ar Sputter gas pressure: 0.5 Pa Input power: 0.9 kW The magnetic film of the information recording medium showed perpendicular magnetization, and the coercive force was about 1 kOe.

This information recording medium was rotated at a rotational speed of 4500 rpm. Magnetic head: write width -2.0 μm, reproduction width -1.5 μm
m, reproduction-MR head, flying height: -30 nm, 200 kfci (mark length: 0.127 μm
Is recorded, and after recording 70 kfci (corresponding to a mark length of 0.36 μm), 400 kf
The characteristic (O / W characteristic) of the residual component at the frequency corresponding to 70 kfci when overwriting with ci (equivalent to 0.064 μm) was measured. Ra on the underlayer was also measured. The results are described below.

Underlayer film thickness (nm) 0, 8, 10, 20, 30, 40, 50, 60, 75, 80 Ra (nm) 0.05, 0.10, 0.15, 0.23, 0.55, 0.73, 0.90, 1.20, 1.50,1.70 SNR (dB) 11.5,14.2,15.8,18.9,21.2,22.0,22.2,18.9,16.2,12.8 O / W (dB) -10, -26, -38, -42, -42, -43, -43, -42, -35, -12

First, when the underlayer was not formed, a current of 60 mA was applied to the magnetic head to apply a magnetic field of about 3 KOe. However, an accurate 1 μm mark could not be recorded on the magnetic film. This is presumably because the exchange coupling force inside the magnetic material is large and the magnetization tends to be oriented in one direction. Therefore, it was found that when Ra was small, it was difficult to form a mark on a magnetic film accurately with a magnetic head. On the other hand, when Ra of the underlayer is increased, SNR and O / W
It was possible to improve the characteristics. In particular, when Ra was in the range of 0.1 to 1.5 nm, the SNR and O / W characteristics were significantly improved.

The reason why the SNR and O / W characteristics are improved is as follows.
In a system that magnetically reproduces information recorded on a magnetic film composed of a rare-earth transition metal amorphous layer, if the base under which the magnetic film is formed is formed with appropriate irregularities, the exchange coupling force in the magnetic material can accurately read the information. It is considered that this is because the recording / reproduction is reduced to an extent that recording / reproduction is possible.

(Embodiment 2) In the first embodiment, the Ra
The SNR and O / W characteristics were examined for the SNR and O / W characteristics.
The W characteristics were examined. An information recording medium was formed in the same manner as in Example 1 except that the superflat substrate used in Example 1 was immersed in hydrochloric acid, and then subjected to mechanochemical polishing to form various Ras on the substrate. . In the same manner as in Example 1, SNR and O
/ W characteristics were measured. The results are described below. Ra (nm) 0.05,0.15,0.23,0.55,0.73,0.90 SNR (dB) 11.5,15.4,17.9,21.7,22.5,22.1 O / W (dB) -10, -23, -39, -41, -43 , -42 From the above results, by forming irregularities on the substrate,
The same result as was obtained.

Embodiment 3 At present, a magnetic recording medium has a CoCrPtTa-based (for example, Co ₇₇ Cr ₁₅ ) as a magnetic film.
A crystalline magnetic material of Pt ₆ Ta ₂ ) is frequently used. Among them, Cr is used to promote isolation of magnetic particles (physical separation of magnetic crystal grains). There have been attempts to add Cr to rare earth transition metal amorphous alloys in order to improve the chemical stability of the magnetic film. In this case, it has been considered that Cr does not generally function like a crystalline magnetic recording medium because Cr is uniformly dispersed in a magnetic material and the film structure is amorphous. Therefore, in the third embodiment, TbFe has C
The recording / reproducing characteristics when r was added were examined.

Specifically, (Tb ₁₅ Fe ₈₅ ) is added to the magnetic film.
_100-x using Cr _x, 30 nm of NiP the underlayer (Ra
An information recording medium was formed in the same manner as in Example 1 except that 0.55) was used, and the change in SNR with respect to x was measured. The SNR was measured in the same manner as in Example 1. The results are described below. Cr content (atom%) 0, 3, 7, 9, 12 SNR 21.2, 22.0, 22.5, 23.1, 23.2 From the above results, it can be seen that adding a nonmagnetic element such as Cr to the amorphous alloy can further improve the SNR. I understood.

(Embodiment 4) In the above embodiment, an amorphous alloy of a rare earth transition metal containing TbFe as a main component was examined. In Embodiment 4, a different alloy was examined. Specifically, the magnetic film is made of Tb ₁₅ Fe _85-x C
except using o _x, the same procedure as in Example 3 to form an information recording medium was measured SNR changes in relative x. The SNR was measured in the same manner as in Example 1. The results are described below. Co amount (atom%) 0, 10, 20, 30, 35 SNR 21.2, 22.0, 23.0, 24.2, 24.5 From the above results, when Co is added to the amorphous alloy, S
It was found that NR could be further improved. It is considered that this is because the value of the saturation magnetization of the magnetic film is increased and the reproduction signal is increased.

(Embodiment 5) A different alloy film, RE
A study was made on rich DyFeCo. Dy
Although FeCo has a smaller perpendicular magnetic anisotropy than TbFe, a larger signal may be obtained due to a larger saturation magnetization value. Further, by making the RE rich, the coercive force increases even when the environmental temperature rises, so that it is considered to be excellent in measures against temperature.

More specifically, RE-rich Dy is added to the magnetic film._{twenty five}
Fe₄₅Co₃₀As in Example 3, except that
Thus, an information recording medium was formed. The coercive force of this magnetic film is about
2 KOe, and the compensation temperature at which the coercive force becomes infinite is about 1
30 ° C. Also, the SNR at 200 Kfci is
It was 24.5 dB. This result is similar to Tb of Example 4. ₁₅
Fe₅₅Co₃₀Was about the same.

Next, Dy ₂₅ Fe ₄₅ Co ₃₀ and Tb ₁₅ Fe ₅₅
The change in SNR with respect to the temperature rise of Co ₃₀ was measured. Specifically, information was recorded in the same manner as in Example 1, and the SNR when the information recording medium was heated to a predetermined temperature and returned to room temperature was measured. The results are described below. Heating temperature (° C) 20, 40, 50, 60, 70, 80 Tb ₁₅ Fe ₅₅ Co ₃₀ 24.2, 24.2, 24.0, 23.5, 23.2, 22.9 Dy ₂₅ Fe ₄₅ Co ₃₀ 24.5, 24.5, 24.4, 24.4, 24.4, 24.4 From the above results, it was found that the RE-rich magnetic film was very effective against the temperature rise.

Example 6 In Example 6, recording / reproducing characteristics when magnetic films having different magnetic characteristics were exchange-coupled were examined. Specifically, 15 nm of TbFe and 3
An information recording medium was formed in the same manner as in Example 3, except that a magnetic film made of a 5 nm TbFeCo laminate was used. Note that TbFe has a substantially compensating composition, Tb ₂₂ Fe ₇₈ having a small magnetization but a large coercive force, and TbFeC
o is Tb ₁₂ Fe ₅₀ Co ₃₈ so that the coercive force is small but the value of the saturation magnetization is large (the former mainly plays a role as a recording layer, and the latter mainly plays a role as a reproducing layer).

The SNR of the obtained information recording medium was determined in Example 1.
The measured value was 24.6, which was better than that of the TbFeCo single-layer film of Example 4. Furthermore,
The SNR of the information recording medium formed in the same manner as described above except that the laminate of Tb ₂₄ Fe ₇₆ and Dy ₂₂ Fe ₄₅ Co ₃₃ was exchange-coupled from the underlayer side was 25.1 dB, and the TbFe and TbFeCo As in the case of the laminate, the results were better than the Dy ₂₅ Fe ₄₅ Co ₃₀ single-phase film of Example 5. From the above, it was found that, even in a magnetic recording medium, SNR characteristics that cannot be obtained with a single-layer film can be obtained by exchange-coupling a rare-earth transition metal amorphous alloy.

Example 7 In Example 7, the recording / reproducing characteristics when the perpendicular magnetization film and the in-plane magnetization film were exchange-coupled were examined. Specifically, GdFeCo of 15 nm from the underlayer side
An information recording medium was formed in the same manner as in Example 3, except that a laminate of (in-plane magnetic film) and 35 nm of DyFeCo (perpendicular magnetic film) was exchange-coupled. Note that GdFeC
For o, Gd ₃₅ Fe ₅₀ Co ₁₅ , which is RE-rich and whose magnetization is saturated at about 3 kOe and has almost no coercive force when a magnetic field is applied in a direction perpendicular to the film surface, is used. Also, DyF
Dy ₂₅ Fe ₄₅ Co ₃₀ was used for eCo. When information of 200 Kfci is recorded on the obtained information recording medium at a recording current of 30 mA, a sufficiently high SNR of 25.5 dB is obtained.
Could be obtained.

On the other hand, except that the in-plane magnetized film is not formed (that is, the magnetic film can only be made of DyFeCo), the information recording medium formed in the same manner as described above has a capacity of 200 Kfc.
When recording the information of i, the recording current required to obtain an SNR of about 25 dB was 50 mA. From the above, it was found that the addition of the in-plane magnetized film as the magnetization reversal auxiliary layer assisted the magnetization reversal and improved the recording magnetic field sensitivity.

(Embodiment 8) An information recording medium combining the configurations of Embodiments 6 and 7, that is, a layer having a large coercive force and a small saturation magnetization, a layer having a small coercive force but a large saturation magnetization,
A magnetic film composed of a magnetization reversal auxiliary layer (reproducing layer / recording layer / magnetization reversal auxiliary layer) was formed. Specifically, 1 from the underlayer side
0 nm Gd ₃₅ Fe ₅₀ Co ₁₅ , 10 nm Tb ₂₄ Fe ₇₆
And except that used as a magnetic film stack of 35nm of Dy ₂₂ Fe ₄₅ Co ₃₃ was formed an information recording medium in the same manner as in Example 3. This information recording medium was able to obtain an SNR of 25.7 dB for a signal of 200 Kfci at a current of 30 mA. According to this result, the reproduction layer /
It has been found that the configuration of the recording layer / the magnetization reversal auxiliary layer further improves the SNR.

(Embodiment 9) Up to now, the magnetic film has been formed under the same conditions.
The size (ie, Ra) of the unevenness of the underlayer may slightly change. In Example 9, the information recording medium was formed by changing the sputtering gas pressure among the conditions for forming the magnetic film. Specifically, an information recording medium was prepared in the same manner as in Example 1 except that the sputtering gas pressure was changed to 1.0 Pa. The SNR of the obtained information recording medium was measured in the same manner as in Example 1. The results are shown below together with the results of Example 1. Underlayer thickness (nm) 0, 10, 20, 30, 40, 50 SNR (dB) 11.5, 15.8, 18.9, 21.2, 22.0, 22.2 (at 0.5 Pa) SNR (dB) 11.5, 17.5, 19.2, 22.2, 23.0, 23.2 (in the case of 1.0 Pa) In other words, the recording characteristics are not uniquely determined with respect to the Ra of the magnetic film, but in order to improve the SNR,
It has been found that the film structure inside the magnetic film, which is induced by the unevenness of the underlayer, is very important.

Example 10 In Example 10, the SNR with respect to the unevenness period of the underlayer was examined. More specifically, the information recording medium is the same as in the first embodiment except that the Ra of the irregularities is made substantially constant by changing the input power at the time of forming the underlayer (NiP layer) and the period of the irregularities is changed. Was formed. The SNR of the obtained information recording medium was measured in the same manner as in Example 1. The results are shown below. Input power (KW): 0.4, 0.7, 1, 1.4, 2.1, 2.9 Uneven period (nm): 6, 10, 20, 30, 40, 50 SNR (dB): 12.0, 16.3, 18.9, 19.2, 17.5, 12.4 From the above, although the period of the column structure of the magnetic film formed thereon is increased / decreased by increasing / decreasing the period of the unevenness on the underlayer, a period of 10 to 40 nm is suitable for recording information. Do you get it.

(Example 11) In Examples 1 to 10, room temperature
However, when the temperature rises, the magnetization of the magnetized film increases.
In some cases, it is possible to be criticized. In particular, rare earth transition gold
In the case of amorphous alloys, the magnetic properties
It can be changed strangely. Therefore, Embodiment 11
Then, the exchange-coupled Tb used in Example 7 was used._{twenty four}Fe₇₆/ D
y _{twenty two}Fe₄₅Co₃₃Temperature changes on the magnetic film made of
By giving Tb_{twenty four}Fe₇₆Increase the magnetization of
As a result, reproduction was performed to obtain a large reproduction signal.

In this embodiment, the recording / reproducing apparatus shown in FIG. 2 was used. In FIG. 2, as means for increasing the temperature during regeneration,
A laser beam having an irradiation diameter of about 15 μm, which is hardly squeezed, is used, and the temperature rises as a whole in a region irradiated with the laser beam. When the power of the laser beam was changed, the following SNR changes were observed with respect to the power change. This is a value when 200 Kfci information is recorded. Irradiation power (mW) 0, 5, 10, 15, 20 SNR (dB) 25.1, 25.5, 26.1, 26.6, 25.5 From above, it was possible to further improve the SNR by heating the magnetic film. The reason why the SNR is lowered at 20 mW is that the recorded signal starts to disappear.

(Embodiment 12) In Embodiment 11, a recording / reproducing apparatus having a recording head and a reproducing head and a laser beam irradiating means having different structures was used. In Embodiment 12, a recording head, a reproducing head and a laser beam were used. A recording / reproducing apparatus integrally provided with irradiation means was used. More specifically, the laser light irradiation means includes a laser light generator and an optical waveguide, and is located before the recording head and the reproducing head in the recording and reproducing directions. In such a recording / reproducing apparatus, the laser beam emitting position and the positions of the recording head and the reproducing head do not relatively change.

Information was reproduced using the recording / reproducing apparatus and the information recording medium of the eleventh embodiment. Irradiation power (mW) 0, 2, 4, 7, 10 SNR (dB) 25.1, 25.5, 26.1, 26.6, 25.5 SNR almost similar to that of Example 11 was obtained, but in this example, laser light was narrowed down. As a result, the irradiation power could be relatively reduced. The irradiation diameter of the laser beam was 0.5 μm.

(Embodiment 13) First, a substrate having a thickness of 20
By forming a SiN film having a thickness of 20 nm, a magnetic film made of Tb ₁₆ Fe ₈₄ (TM rich) or a magnetic film made of Tb ₂₈ Fe ₇₂ (RE rich), and a SiN film having a thickness of 20 nm, two types of information recording media can be obtained. Then, the respective magnetic characteristics were examined. The magnetic film was formed by using a known magnetron sputtering apparatus and sputtering a target having each composition to a sputtering gas (Ar) pressure of 0.5 Pa and a sputtering rate of 30 nm / m.
It was manufactured under the conditions described below. When the magnetic film is made of Tb ₁₆ Fe ₈₄ , the coercive force at room temperature is 3 kOe, the coercive force at 65 ° C. is 2 kOe, and the saturation magnetization is 200 emu / cc.
Met. When the magnetic film is made of Tb ₂₈ Fe ₇₂ , the coercive force at room temperature is 3 kOe, and the coercive force at 65 ° C. is 4 kOe.
e, and the saturation magnetization was 150 emu / cc.

Next, as shown in FIG. 8, the two kinds of magnetic films were successively laminated. Specifically, on the substrate 1, 20
An underlayer 2 composed of a 10 nm SiN film, a 10 nm NiP film, and a 2 nm C film was formed in this order. Furthermore, on the C film,
A magnetic film 7 made of 12 nm Tb ₂₈ Fe ₇₂ and a magnetic film 8 made of 32 nm Tb ₁₆ Fe ₈₄ were continuously formed. Thereafter, a protective layer 9 made of 7 nm SiN and a solid lubricating layer (not shown) made of 3 nm C were formed in this order to obtain an information recording medium in which both magnetic films were exchange-coupled. The coercive force of the information recording medium at room temperature is about 2.7 kO.
e, tBr is 58 Gauss μm, 65 ° C.
Is 4 kOe, and tBr is 60 Gauss.
μm.

The above-mentioned information recording medium was evaluated by recording and reproducing as follows using an actual magnetic disk drive. When a magnetic disk drive was installed in a thermo-hygrostat kept at about 25 ° C and recorded and reproduced by a merge type GMR,
By setting the recording current Iw to about 15 mA, the signal amplitude was saturated, and the O / W (recording 240 Kfci over 20 Kfci) characteristic showed a good value of -40 dB. Also,
The SNR at 240 Kfci also showed a value of 21 dB.

Even when the temperature and humidity chamber was kept at 65 ° C., when recording and reproduction were performed by the same merge type GMR, Iw was about 17 m.
By setting to A, the signal amplitude is saturated and the O / W characteristic is also -38.
It showed a good value of dB. The SNR at 240 Kfci also showed a value of 21.3 dB. Furthermore,
The signal recorded at room temperature and at 65 ° C. was able to maintain the SNR immediately after recording without any change even after 2 hours.

(Example 14) TbF was used as a TM-rich film.
A DyFeCo film was used as an RE-rich film using an eCo film. Specifically, a Tb ₁₅ Fe ₇₅ Co ₁₀ film (Hc =
2.7kOe, Ms = 200emu / cc, film thickness 40n
m) and a Dy ₂₉ Fe ₆₁ Co ₁₀ film (Hc = 2.5 kOe, M
An information recording medium was obtained in the same manner as in Example 13, except that s = 130 emu / cc, and a film thickness of 10 nm.
The coercive force of this information recording medium at room temperature was about 3.1 kOe, and tBr was 84 Gauss μm. Also, 4
The coercive force at 0 ° C. was 3.2 kOe, and the coercive force at 65 ° C. was 4 kOe.

Accordingly, for magnetic recording on this medium, a magnetic field of about 3.4 kOe was sufficient at room temperature and 65 ° C., and the recorded information did not disappear. Further, when the recording characteristics and data stability were examined using the same magnetic disk drive as in Example 13, the O / W was-
Good at 38 dB, 22 dB S at 240 Kfci
NR was obtained. Furthermore, the SNR at the time when two hours had elapsed after recording was 22 dB, and the signal did not deteriorate.

(Embodiment 15) Dy ₂₀ as a TM-rich film
An information recording medium was obtained in the same manner as in Example 13, except that a Fe ₅₀ Co ₃₀ film (film thickness: 20 nm) was used and a Tb ₂₈ Fe ₆₀ Co ₁₂ film (film thickness: 40 nm) was used as the RE-rich film. . The coercive force at room temperature of this information recording medium is about 2.7.
kOe and tBr was 72 Gauss μm.
The coercive force at 40 ° C. is 2.9 kOe,
Was 3.1 kOe. Furthermore, the SNR when 2 hours had elapsed after recording was 20.8 dB, and the signal was only slightly degraded.

(Embodiment 16) An embodiment 13 except that the period of the unevenness of the NiP film as the underlayer is changed as follows.
An information recording medium was obtained in the same manner as described above. The period of the irregularities was adjusted by changing the power supplied to the sputter. The tBr of the magnetic film was 58 Gauss μm, which was the same as in Example 13. S at 240 Kfci of the obtained information recording medium
The NR was measured. The results are shown below. Input power (kW): 0.4, 0.7, 1.0, 1.4, 2.1, 2.9 Uneven period (nm): 6, 10, 20, 30, 40, 50 SNR (dB): 15.0, 19.4, 21.0, 21.3, 21.2, 15.4 It was found that a more favorable SNR was obtained when the period of the irregularities was about 10 to 40 nm.

(Embodiment 17) Embodiment 13 except that the Ra of the unevenness of the NiP film as the underlayer is changed as follows.
An information recording medium was obtained in the same manner as described above. Ra of unevenness is Ni
It was adjusted by changing the thickness of P. The tBr of the magnetic film was 58 Gauss μm, which was the same as in Example 13.
SNR of obtained information recording medium at 240 Kfci
And O / W were measured. The results are shown below. NiP film thickness (nm): 0, 8, 10, 20, 30, 40, 50, 60, 70, 80 Ra (nm): 0.05, 0.10, 0.15, 0.23, 0.55, 0.73, 0.90, 1.20, 1.50, 1.70 SNR (dB): 14.5,19.2,21.0,21.3,21.2,22.0,21.5,19.0,18.3,12.8 O / W (dB): -10, -32, -40, -41 -41, -40,- 43, -42, -35, -12 When Ra is about 0.1 to 1.5 nm, more preferable S
It was found that NR was obtained.

(Embodiment 18) TbFeCo film and DyFe
An information recording medium was obtained in the same manner as in Example 14, except that the thickness of the Co film was changed as follows. The SNR and tBr of the obtained information recording medium were measured. The results are shown below. TbFeCo (nm): 90, 80, 60, 50, 40, 30, 29, 27, 25, 20, 20, 20 DyFeCo (nm): 10, 10, 10, 10, 10, 10, 10, 10, 10 , 10, 25, 27 tBr (Gaussμm): 210,184,134,109, 59, 57, 56, 52, 46, 33, 27, 6 SNR (dB): 19, 21, 22, 23, 22, 22, 21, 16, 14 , 10, 5, 1, 1 When tBr is 55 Gauss μm or more, preferable SN
It was found that R was obtained. Furthermore, 57 to 134 Ga
It was found that the range of uss μm was more preferable.

[0078]

According to the information recording medium of the present invention, minute recording marks can be stably recorded at an ultra-high density, and the recorded information can be reproduced using an existing magnetic reproducing head.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an information recording medium of the present invention.

FIG. 2 is a schematic configuration diagram of a recording / reproducing apparatus.

FIG. 3 is a plan view showing the concept of recording and / or reproducing information.

FIG. 4 is a schematic configuration diagram of an information recording / reproducing slider of the present invention.

FIG. 5 is an enlarged schematic sectional view of a main part of the slider of the present invention.

FIG. 6 is an enlarged schematic sectional view of a main part of the slider of the present invention.

FIG. 7 is a graph showing a change in magnetization with respect to the amount of Tb in TbFe.

FIG. 8 is a schematic sectional view of an information recording medium according to Embodiment 13 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Underlayer 3 Information recording film 4, 23, 33 Laser light irradiation means 6 Magnetic head part 7, 8 Magnetic film 9 Protective layer 11 Heating area 12 Magnetic head 13 Track pitch 21, 61 Slider 22 Slider support means 31 Recording Head 32 Magnetic reproduction head 41 Laser 42 Collimator lens 43 Splitter 44 Objective lens 45 1/2 wavelength plate 45 46 Deflection beam splitter 47, 49 Condensing lens 48, 50 Photodetector 51 Amplifier 62 Amplifier circuit 63 Integration circuit 64 Demodulation circuit 65 , 66 Switching terminal 67 Common terminal A Information recording medium

Claims (6)

[Claims] An information recording film mainly composed of an amorphous alloy of a rare earth transition metal capable of magnetically reproducing recorded information is provided on a substrate having irregularities of Ra of 0.1 to 1.5 nm. Information recording medium. 2. An information recording medium comprising an information recording film mainly composed of a rare earth transition metal amorphous alloy capable of magnetically reproducing recorded information on a substrate having irregularities having a period of 10 to 40 nm. . 3. An information recording film comprising an exchange coupling multilayer film capable of magnetically reproducing recorded information, wherein the exchange coupling multilayer film has a coercive force substantially in a temperature range from room temperature to around 65 ° C. An information recording medium that does not change, has a residual magnetic flux density × film thickness of 55 Gauss μm or more, and includes at least a transition metal rich rare earth transition metal amorphous alloy layer and a rare earth rich rare earth transition metal amorphous alloy layer. 4. An exchange-coupled multilayer film having a Ra of 0.1 to 1.
5 nm unevenness, a period of 10 to 40 nm unevenness or 2
4. The information recording medium according to claim 3, wherein the information recording medium is formed on a substrate having irregularities satisfying the following two conditions. 5. The transition metal rich rare earth transition metal amorphous alloy layer and the rare earth rich rare earth transition metal amorphous alloy layer contain at least Tb or Dy.
Or the information recording medium according to 4. 6. An information recording / reproducing slider used when recording and reproducing information on / from the information recording medium according to claim 1, wherein the slider is an integrated light irradiator. An information recording / reproducing slider comprising a recording head and a magnetic reproducing head, wherein the light irradiating means is positioned before the recording head and the magnetic reproducing head in the recording and reproducing directions of the information.