JP2967698B2 - Manufacturing method of magnetic recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a magnetic recording medium used in a magnetic disk drive.

[0002]

2. Description of the Related Art In recent years, demands for high recording density recording on magnetic recording media such as hard disks have become increasingly severe in recent years.

Here, a magnetic recording medium such as a hard disk generally has a base film, a magnetic film, and a protective film formed sequentially on a non-magnetic substrate, on which a head slider on which a magnetic head is mounted is caused to fly. While recording and reproducing. Therefore, in order to realize high-density recording of this magnetic recording medium, in addition to increasing the coercive force of the magnetic film, the flying height of the head slider is reduced and CSS (contact staging) is performed.
It is important to improve the durability against art and stop). That is, it is necessary to reduce the distance between the magnetic head and the magnetic film at the time of recording / reproducing by allowing the head slider to travel at a low flying height, thereby enabling high-density recording / reproducing. In addition, when this low levitation traveling is made,
The physical / mechanical load applied to the magnetic head and the magnetic recording medium increases rapidly during the repetitive operation (CSS) of switching between sliding traveling and floating traveling when the head slider starts and stops traveling. The durability of magnetic heads and magnetic recording media in
). Further, with the increase in the recording density, it is also required to reduce the noise during reproduction.

[0004] By the way, most hard disks at present use an aluminum alloy substrate as a non-magnetic substrate, apply Ni-P plating to the surface thereof, polish the surface, and then apply a texturing process to impart an appropriate surface roughness to the surface. After that, a base film, a magnetic film, a protective film, and the like are formed sequentially by sputtering. That is, the head slider is attracted to the magnetic recording medium at the time of CSS, so that unevenness due to the surface roughness due to texture processing appears on the surface of the protective film via the base film and the magnetic film, or
The frictional force between the two is prevented from becoming larger than a predetermined value.

A method has also been proposed in which a polysilicic acid or glassy coating film is formed as a protective film so that a predetermined surface roughness appears on the protective film surface (for example, Japanese Patent Publication No. 1-18500). Reference).

Further, recently, a magnetic recording medium using a glass substrate as a non-magnetic substrate has been attracting attention as a device which is likely to be able to easily achieve a higher recording density. This is due to the fact that glass is
High recording density is achieved due to its excellent physical and chemical durability, such as having sufficient hardness to cope with thinning, and the ability to form its surface relatively easily and with high planar accuracy. Because it has been found to be more suitable.

[0007]

By the way, in order to realize a high coercive force of a magnetic film, a low flying running of a head slider, a high CSS and the like required for a high density recording of a magnetic recording medium, it is necessary to use a substrate. It is necessary not only to improve the basic characteristics such as the magnetic characteristics of each film formed on the substrate, but also to improve the physical strength, smoothness, adhesion of each film, etc. However, in the above-described conventional magnetic recording media, there is a certain limit in improving such characteristics.

The present invention has been made in view of the above background, and has as its object to provide a magnetic recording medium capable of easily realizing a high coercive force, a low flying height, and a high CSS, and a method of manufacturing the same. The purpose is.

[0009]

In order to solve the above-mentioned problems, a method for manufacturing a magnetic recording medium according to the present invention comprises: (Constitution 1) A non-magnetic substrate includes at least an underlayer, a magnetic layer, and a protective layer. In the method for manufacturing a magnetic recording medium having a step of forming a layer, the nonmagnetic substrate is a glass substrate, the magnetic layer is a CoNiCrTa-based magnetic layer, and the magnetic layer and the protective layer are formed after the magnetic layer is formed. And an intermediate layer forming step of forming an intermediate layer between the protective layer, the protective layer forming step includes a step of applying a raw material of the protective layer on the intermediate layer and heating and curing the intermediate layer. A heating step of heating the substrate at a temperature of 250 to 400 ° C. during the layer formation process or after the formation of the protective layer, wherein (Structure 2) the magnetic layer is Co _100-abc Ni _a Cr _b
Ta _c (where a, b, and c represent atomic%, and 20 ≦ a ≦
b, 6.5 ≦ b ≦ 10, 0.3 ≦ c ≦ 1.7)
A configuration wherein there, as an embodiment of the structure 1 or 2, (Structure 3) wherein the intermediate layer is Cr layer having a thickness of 20 to 200 Angstroms or Cr-Y system (wherein, Y is, M
o, Zr, B, W, Ta, or Si). As an aspect of Configurations 1 to 3 , (Configuration 4 ) A first underlayer mainly composed of any one or more of Al, Si, Pb, Cu, In or Ga formed on the side in contact with the substrate; and a Cr formed on the first underlayer. it is intended that a second underlying layer made of a structure, wherein the structure 4
As a mode of the present invention, (Structure 5 ) The structure is characterized in that the thickness of the first underlayer is 10 to 100 Å.

[0010]

According to the above configuration 1, a glass substrate is used as the nonmagnetic substrate, the magnetic layer is a CoNiCrTa-based magnetic layer, and an intermediate layer is formed between the magnetic layer and the protective layer after the formation of the magnetic layer. The intermediate layer forming step, the protective layer forming step includes a step of applying a raw material of a protective layer in which hard fine particles are dispersed in a liquid base material on the intermediate layer, heating and curing, During the protective layer forming process or after forming the protective layer, 2
By having a heating step of heating the substrate at a temperature of 50 to 400 ° C., the coercive force of the magnetic film can be increased, and at the same time, the adhesion between the magnetic film and the protective film and the film adhesion can be improved and each film can be improved. , The flying height and the CSS of the head slider can be reduced to a higher level, and the recording density of the magnetic recording medium can be further increased.

Here, the heating temperature in the heating step is set to 25.
The reason why the temperature is set to 0 to 400 ° C. is that if the temperature is lower than 250 ° C., a sufficient coercive force improvement effect and the film strength of the protective film cannot be obtained, and if the temperature exceeds 400 ° C., the magnetization / thickness product decreases. is there.

In this case, as in Configuration 3 , the intermediate layer is a Cr layer having a thickness of 20 to 200 angstroms or a Cr-Y type (where Y is one of Mo, Zr, B, W, Ta or Si). Or two or more). If the film thickness is less than 20 angstroms, the coercive force will be reduced, and if it exceeds 200 angstroms, the distance between the magnetic film and the head will be too long during recording / reproducing, causing a significant decrease in sensitivity.

Further, as in Configuration 4 , the underlayer is constituted by a first underlayer made of a metal having a relatively low melting point and a second underlayer made of Cr formed on the first underlayer. This makes it possible to improve the crystal structure of the magnetic layer formed on the second underlayer and improve the magnetic properties such as coercive force.

In this case, it is desirable that the thickness of the first underlayer be 10 to 100 Å, as in the fifth aspect . If the thickness is less than 10 angstroms, the coercive force decreases and noise increases, and if it exceeds 100 angstroms, the reproduction output decreases.

[0015]

【Example】

(Embodiment 1) FIG. 1 is a schematic sectional view showing the configuration of a magnetic recording medium manufactured by a method for manufacturing a magnetic recording medium according to Embodiment 1 of the present invention. Hereinafter, the first embodiment will be described with reference to FIG.
Next, a magnetic recording medium manufactured by the manufacturing method according to the first embodiment will be described, and then a method for manufacturing the magnetic recording medium of the first embodiment will be described.

As shown in FIG. 1, the magnetic recording medium manufactured by the manufacturing method of this embodiment is, in short, a first underlayer 2, a second underlayer 3, and a third underlayer 3 sequentially on a glass substrate 1. This is a magnetic disk on which an underlayer 4, a magnetic layer 5, an intermediate layer 6, a protective layer 7, and a lubricating layer 8 are formed.

The glass substrate 1 is made of chemically strengthened glass having an outer diameter of 65 mmφ, a central hole diameter of 25 mmφ, and a thickness of 0.9 mm.
And the two main surfaces have a surface roughness of Rm.
It is precisely polished so that ax is 30 angstroms.

Here, as a chemically strengthened glass constituting the glass substrate 1, SiO ₂ is used as a main component in weight%.
There 62~75%, Al ₂ O ₃ is 5 to 15%, LiO ₂ is 4~10%, Na ₂ O is 4 to 12%, ZrO ₂ 5.5
-15% each, and Na ₂ O / ZrO
_The glass for chemical strengthening in which the weight ratio of Al ₂ O ₃ / ZrO ₂ is 0.4 to 2.5 and the weight ratio of
What was chemically strengthened by ion exchange treatment in a treatment bath containing a ion and / or K ion (for details, see JP-A-5-32431) was used.

The first underlayer 2 is an Al thin film having a thickness of about 60 angstroms.

The second underlayer 3 is a Cr film having a thickness of about 600 angstroms.

The third underlayer 4 is a Cr film having a thickness of about 1200 angstroms.

The magnetic layer 5 is a CoNiCrTa film having a thickness of about 800 Å. Here, CoNiCr
The composition of the Ta film is expressed as Co: Ni: C in atomic (at) % ratio.
r: Ta = 66: 25: 8: 1 (a = 25, b = 8, c
= 1).

The intermediate layer 6 is a Cr layer having a thickness of about 50 Å formed on the magnetic layer 5.

In the protective layer 7, silica (SiO ₂ ) fine particles 7b are dispersed in a silicon oxide (polysilicic acid) film 7a, and irregularities due to the silica fine particles appear on the surface. The thickness of the silicon oxide film 7a where the silica fine particles 7b are not present is about 100 Å. The silica fine particles 7b have an average particle size of about 12
0 Angstrom. Here, the average particle size of the silica fine particles is the average size of the silica fine particles, that is, the average size obtained by measuring the diameter of a group of silica fine particles including the spherical and non-spherical silica fine particles. Means

The lubricating layer 6 is made of a lubricant made of perfluoropolyether (for example, AM2001 manufactured by Montezison).
Is coated on the protective film 5 by an immersion method to form a film having a thickness of about 20 angstroms.

The lubricating layer 8 is made of a lubricant made of perfluoropolyether (for example, AM2001 manufactured by Montezison).
Is applied on the protective layer 7 by an immersion method to form a film having a thickness of about 20 angstroms.

Next, a method of manufacturing the magnetic recording medium of the above embodiment will be described.

First, a chemically strengthened glass having an outer diameter of 65 mm was used.
φ, a central hole diameter of 25 mmφ, and a thickness of 0.9 mm are formed in a disk shape, and both main surfaces have a surface roughness of Rmax 3
The glass substrate 1 is obtained by precision polishing so as to have a thickness of 0 Å.

Next, the glass substrate 1 is subjected to a heat treatment, a first underlayer 2, a second underlayer 3, a third underlayer 4, and a magnetic layer 5. And intermediate layer 6
Are successively performed using an in-line sputtering apparatus.

As the in-line sputtering apparatus, a well-known in-line type DC magnetron sputtering apparatus was used. Although not shown, the in-line sputtering apparatus includes a first chamber provided with a substrate heater, a second chamber provided with an Al target and a Cr target sequentially, a Cr target and a Co
A third chamber in which NiCrTa targets are sequentially installed and a fourth chamber in which Cr targets are installed are provided.

Then, when the glass substrate 1 is introduced into the first chamber via the load lock chamber, the glass substrate 1 is successively conveyed in each chamber at a predetermined constant speed by a predetermined conveying device. In the meantime, the following film formation and processing are performed.

That is, first, in the first chamber, a process of heating the substrate at 375 ° C. is performed. In the second chamber, an Al film having a thickness of 60 Å as the first underlayer 2 and a Cr film having a thickness of 600 Å as the second underlayer 3 are sequentially formed. In the third chamber, a Cr film having a thickness of 1200 Å as the third underlayer 4 and a CoNiCrTa film having a thickness of 800 Å as the magnetic layer 5 are sequentially formed. In the fourth chamber, a 50 angstrom thick Cr film 6 constituting the intermediate layer 6 is formed. The pressure in each chamber is reduced to a pressure of 1 × 10 ⁻⁵ Torr or less, and argon is used as a sputtering gas. The sputtering gas pressure is 5 mTorr in the second chamber, 2 mTorr in the third chamber, and 5 mTorr in the fourth chamber.

Thus, the substrate formed up to the intermediate layer 6 is taken out from the in-line sputtering apparatus, and the protective layer 7 is formed on the intermediate layer 6.

The protective layer 7 is formed by bringing the surface of the intermediate layer 6 into contact with a liquid in which hard fine particles are dispersed, applying the liquid, and subjecting the entire substrate to heat treatment and curing. In this case, this liquid was measured with tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ) as an organosilicon compound and an average particle size of about 100 Å (a Coulter Counter N4 particle size distribution analyzer). (Value), water and isopropyl alcohol at a weight ratio of 10: 0.3: 3: 500. The heat treatment after the application of the liquid material is a treatment of heating at a temperature of about 280 ° C. Thereby, the protective layer 7 in which the silica fine particles 7b are dispersed in the silicon oxide (polysilicic acid) film 7a is obtained. In the case of this example, silica fine particles 7
The film thickness of the portion where a does not exist is about 100 angstroms.

Next, perfluoropolyether is applied to the surface of the protective layer 7 by spin coating, and a thickness of 2
The lubrication layer 8 of 0 Å is formed to obtain the magnetic recording medium according to the first embodiment.

(Embodiments 2 to 4) In Embodiments 2 and 3 above, only the heat treatment temperature in the step of forming the protective layer 7 in Embodiment 1 was changed to 400 ° C., 330 ° C., and 250 ° C. , 4.

(Example 5) The composition ratio of the magnetic layer 5 in the above-mentioned Example 1 was changed to Co: Ni: Cr: Ta = 66.7:
Except that the ratio was changed to 25: 8: 0.3, Example 5 had the same configuration (heat treatment temperature: 280 ° C.) as Example 1.

(Embodiment 6) The composition ratio of the magnetic layer 5 in the above-mentioned Embodiment 1 was changed to Co: Ni: Cr: Ta = 65.3:
Except that the ratio was changed to 25: 8: 1.7, Example 6 had the same configuration (heating temperature; 280 ° C.) as Example 1.

(Embodiment 7) The composition ratio of the magnetic layer 5 in the above-described embodiment 1 was changed to Co: Ni: Cr: Ta = 67.5:
Example 7 was the same as Example 1 except that the ratio was changed to 25: 6.5: 1 and the heat treatment temperature at the time of forming the protective layer 7 was changed to 350 ° C.

(Embodiment 8) The composition ratio of the magnetic layer 5 in the above-mentioned Embodiment 1 was changed to Co: Ni: Cr: Ta = 64: 2.
Example 8 was the same as Example 1 except that the ratio was changed to 5: 10: 1 and the heat treatment temperature at the time of forming the protective layer 7 was changed to 250 ° C.

(Embodiment 9) Only the composition ratio of the magnetic layer 5 in the above-described embodiment 1 was determined by using the following formula: Co: Ni: Cr: Ta = 71:
Except that the ratio was changed to 20: 8: 1, Example 9 had the same configuration as that of Example 1 (heat treatment temperature: 280 ° C.).

(Embodiment 10) The composition ratio of the magnetic layer 5 in the above-described embodiment 1 was changed to Co: Ni: Cr: Ta = 61: 3.
Example 10 was the same as Example 1 except that the ratio was changed to 0: 8: 1 and the heat treatment temperature at the time of forming the protective layer 7 was changed to 340 ° C.

(Examples 11 to 14) The same structure as in Example 1 except that the thickness of the intermediate layer 6 in Example 1 was changed to 30 Å, 100 Å, 150 Å, and 200 Å. Were defined as Examples 11, 12, 13, and 14.

(Embodiments 15 to 18) The thickness of the first underlayer 2 in the above-mentioned Embodiment 1 was set to 10 Å, 30
Embodiments 15, 16, 17, and 18 have the same configuration as Embodiment 1 except that they are changed to Å, 50 Å, and 100 Å, respectively.

(Comparative Examples 1 and 2) Only the heat treatment temperature at the time of forming the protective layer 7 in Example 1 was 220 ° C.
Except that the temperature was changed to 0 ° C. (both were less than 250 ° C.), Comparative Examples 1 and 2 were the same as those of Example 1 except for the same configuration.

(Comparative Example 3) The composition ratio of the magnetic layer 5 in the above-mentioned Example 1 was changed to Co: Ni: Cr: Ta = 66.8:
25: 8: 0.2 (Ta is less than 0.3%) and the same structure as in Example 1 except that the heat treatment temperature at the time of forming the protective layer 7 was changed to 260 ° C. Comparative Example 3 was used.

(Comparative Example 4) The composition ratio of the magnetic layer 5 in the above-mentioned Example 1 was changed to Co: Ni: Cr: Ta = 65: 2.
5: 8: 2 (Ta exceeds 1.7%) and
Comparative Example 4 was the same as Example 1 except that the heat treatment temperature at the time of forming the protective layer 7 was changed to 270 ° C.

(Comparative Example 5) The composition ratio of the magnetic layer 5 in the above-mentioned Example 1 was changed to Co: Ni: Cr: Ta = 68: 2.
5: 6: 1 (Cr less than 6.5%) and the same configuration as in Example 1 except that the heat treatment temperature at the time of forming the protective layer 7 was changed to 310 ° C. Comparative Example It was set to 5.

(Comparative Example 6) The composition ratio of the magnetic layer 5 in the above-mentioned Example 1 was changed to Co: Ni: Cr: Ta = 63: 2.
5: 11: 1 (Cr exceeds 10%) and
Comparative Example 6 was the same as Example 1 except that the heat treatment temperature at the time of forming the protective layer 7 was changed to 275 ° C.

(Comparative Example 7) The composition ratio of the magnetic layer 5 in the above-mentioned Example 1 was changed to Co: Ni: Cr: Ta = 73: 1.
Example 1 except that the ratio was changed to 8: 8: 1 (Ni was less than 20%).
Comparative Example 7 having the same configuration as that of Example 1 (heat treatment temperature: 280 ° C.).

(Comparative Example 8) The composition ratio of the magnetic layer 5 in the above-mentioned Example 1 was changed to Co: Ni: Cr: Ta = 58: 3.
Except that the ratio was changed to 5: 8: 1 (Ni exceeds 30%), it has the same configuration as in Example 1 (heat treatment temperature: 280 ° C.).
This was designated as Comparative Example 8.

(Comparative Examples 9 to 10) Only the heat treatment temperature at the time of forming the protective layer 7 in Example 1 was 430 ° C.
Except that the temperature was changed to 50 ° C. (both exceeding 400 ° C.), those having the same configuration as in Example 1 were compared with Comparative Example 9 and Comparative Example 9, respectively.
It was set to 10.

(Comparative Examples 11 to 12) The thickness of the intermediate layer 6 in Example 1 was set to 15 Å (less than 20 Å) and 250 Å (200 Å).
Comparative Examples 11 and 12, respectively, except that the heat treatment temperature during the formation of the protective layer 7 was changed to 310 ° C.

(Comparative Examples 13 and 14) The thickness of the first underlayer 2 in Example 1 was set to 5 Å (less than 10 Å) and 150 Å (10 Å).
0 Angstroms), and
Except that the heat treatment temperature at the time of forming the protective layer 7 was both changed to 310 ° C., those having the same configuration as in Example 1 were used as Comparative Examples 13 and 14, respectively.

FIG. 2 is a table showing the results of measuring the characteristics of the magnetic recording media of Examples 1 to 18 described above, and FIG. 3 shows the characteristics of the magnetic recording media of Comparative Examples 1 to 14. It is the figure which showed the result as a table.

The coercive force (Hc) was measured by cutting a sample of 8 mmφ from the manufactured magnetic recording medium, applying a magnetic field in the direction of the film surface, and measuring the maximum externally applied magnetic field of 10 kOe using a vibrating sample magnetometer. .

The recording / reproducing characteristics (reproducing output and medium noise) were measured as follows. That is, using the obtained magnetic disk, the flying height of the magnetic head is set to 0.
Using a 55 μm thin film head, the relative speed between the thin film head and the magnetic disk was 6 m / s, and the linear recording density was 70 kfcl.
The recording / reproducing output at (a linear recording density of 70,000 bits per inch) was measured. The noise spectrum at the time of signal recording and reproduction was measured by a spectrum analyzer with a carrier frequency of 8.5 MHz and a measurement band of 15 MHz. The thin film head used in this measurement has 50 coil turns, a track width of 6 μm, and a magnetic head gap length of 0.25 μm.

As is clear from the table of FIG. 2, the heat treatment temperature in the step of forming the protective layer 7 is 250 to 400 ° C., and the composition of the magnetic layer 5 to be formed is Co _100-abc
Ni _a Cr _b T _ac (where a, b, and c are atoms (at)
%, 20 ≦ a ≦ 30, 6.5 ≦ b ≦ 10, 0.3
≦ c ≦ 1.7), the thickness of the first underlayer 2 is 10 to 100 Å, and the thickness of the intermediate layer 6 is 20 to 200 Å.
In the case of the above, all the obtained magnetic recording media have excellent characteristics such as a coercive force of 1680 Oe or more, a reproduction output of 175 μV or more, and a medium noise of 2.8 μVrms or less.

On the other hand, as is clear from the comparison between the tables of FIG. 2 and FIG. 3, the composition of the magnetic layer 5, the heat treatment temperature in the process of forming the protective layer 7, the thickness of the first underlayer 2 and the intermediate In Comparative Examples 1 to 14, in which any one or two or more of the thickness of the layer 6 is not in the above range, any one or more of the properties of the coercive force, the reproduction output, and the noise are compared with those of the examples. Inferior.

Although the present invention has been described with reference to the embodiments, the present invention includes the following modifications and application examples.

In the above-described embodiment, an example in which an aluminosilicate-based chemically strengthened glass is used as the substrate has been described.
Other glasses such as borosilicate, aluminoborosilicate, quartz glass, soda lime glass, etc. can be used. These can be easily polished and finished to have a surface roughness of 100 angstrom or less in Rmax. Further, the outer diameter of the substrate may be made smaller and the thickness may be made thinner.

Further, in the embodiment, the case where the first underlayer is made of Al is described, but this may be one in which one or more of Si, Pb, Cu, In or Ga is a main component. .

In the embodiment, the case where the second underlayer is made of Cr is cited, but this is because TiW, Mo, Ti, T
Non-magnetic materials such as a, W, Zr, Cu, A, Zn, In, and Sn can be used. Note that these underlayers may be composed of two or more layers.

The underlayer, the magnetic layer, the intermediate layer and the like can be formed not by using an in-line sputtering apparatus but by using an ordinary sputtering apparatus.

In the embodiment, the example in which the intermediate layer is made of Cr has been described.
Other materials may be used, such as Mo, Ti,
Non-magnetic materials such as TiW, CrMo, Ta, W, Si, and Ge, or oxides, nitrides, carbides, and the like thereof may be used. Further, this layer may be two or more layers.

Further, in the embodiments, perfluoropolyether is used as the material of the lubricating layer, but a fluorocarbon liquid lubricant or a lubricant composed of an alkali metal salt of sulfonic acid may be used. The thickness is preferably 10 to 30 angstroms, and the reason is 10 to 30 angstroms.
If the thickness is less than Å, the abrasion resistance cannot be sufficiently improved, and if it exceeds 30 Å, the abrasion resistance cannot be improved, and a problem of spacing loss occurs.

[0067]

As described above in detail, according to the present invention, a glass substrate is used as a nonmagnetic substrate, and a magnetic layer is made of CoNiCrT.
an a-based magnetic layer, comprising an intermediate layer forming step of forming an intermediate layer between the magnetic layer and the protective layer after forming the magnetic layer,
Further, the protective layer forming step includes a step of applying a raw material for the protective layer in which the hard fine particles are dispersed in the liquid base material on the intermediate layer and heating and curing the raw material. By having a heating step of heating the substrate at a temperature of 250 to 400 ° C. later, the coercive force of the magnetic film can be increased, and at the same time, the adhesion between the magnetic film and the protective film and the film adhesion can be improved. It is possible to improve the strength of the membrane,
This makes it possible to realize a low flying height and a high CSS of a head slider at a higher level, thereby enabling a higher density recording of a magnetic recording medium.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a configuration of a magnetic recording medium manufactured by a method for manufacturing a magnetic recording medium according to a first embodiment of the present invention.

FIG. 2 is a table showing the results of measuring characteristics of the magnetic recording media of Examples 1 to 18.

FIG. 3 is a table showing the results of measuring characteristics of the magnetic recording media of Comparative Examples 1 to 14.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 2 ... 1st underlayer, 3 ... 2nd underlayer, 4
... third underlayer, 5 ... magnetic layer, 6 ... intermediate layer, 7 ... protective layer,
8: Lubricating layer.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hisao Kawai 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo Inside Hoya Co., Ltd. (56) References JP-A-6-259767 (JP, A) JP JP-A-5-197942 (JP, A) JP-A-5-234059 (JP, A) JP-A-6-28657 (JP, A) JP-A-6-29121 (JP, A) (58) Fields investigated (Int) .Cl. ⁶ , DB name) G11B 5/86 G11B 5/66 H01F 10/26 H01F 41/18

Claims (5)

(57) [Claims] 1. A method for manufacturing a magnetic recording medium, comprising: forming a layer including at least an underlayer, a magnetic layer, and a protective layer on a nonmagnetic substrate, wherein a glass substrate is used as the nonmagnetic substrate, Is a CoNiCrTa-based magnetic layer, and has an intermediate layer forming step of forming an intermediate layer between the magnetic layer and the protective layer after the formation of the magnetic layer. A process of applying and heating and curing the raw material of the protective layer, and performing the protective layer forming process or after the formation of the protective layer.
A method for manufacturing a magnetic recording medium, comprising a heating step of heating a substrate at a temperature of 0 ° C. 2. The magnetic layer according to claim 1, wherein said magnetic layer is Co _100-abc Ni _a C
r _b Ta _c (where, a, b, c, represents the atomic%, 20
≦ a ≦ 30, 6.5 ≦ b ≦ 10, 0.3 ≦ c ≦ 1.7
2. The magnetic recording device according to claim 1, wherein
Recording medium. 3. The intermediate layer according to claim 1, wherein the intermediate layer has a thickness of 20 to 200 angstroms or a Cr layer or a Cr—Y type (where Y is M
o, Zr, B, W, Ta, or Si).
Or the method for manufacturing a magnetic recording medium according to 2 . 4. The first underlayer having at least one of Al, Si, Pb, Cu, In or Ga formed on the side in contact with the substrate, and the method of manufacturing a magnetic recording medium according to any one of claims 1 to 3, characterized in that 1 the base layer second underlayer made of Cr formed on the one having a multilayer structure comprising at least . 5. The method according to claim 4 , wherein the thickness of the first underlayer is 10 to 100 Å.