JPH05128481A - Magnetic recording medium and production thereof and magnetic disk device constituted by using the medium - Google Patents

Abstract

PURPOSE:To provide the magnetic recording medium which has uniform magnetic characteristics within a medium surface and less modulations and can make high-density recording and the method for producing such medium with good reproducibility, and the magnetic disk device of a small size and small capacity using such medium. CONSTITUTION:This medium is constituted by forming the substrate layer of a magnetic layer into a two-layered structure consisting of 1st and 2nd layers, incorporating 0.1 to 50at.% at least one kind of elements Z among oxygen, fluorine and nitrogen or incorporating 0.001 to 5at.% hydrogen into at least either of the substrate layer and the magnetic layer 14. As a result, crystal nuclei are uniformly formed with good reproducibility within the medium plane and the crystallinity and orientability are uniformed in the medium plane in the initial stage of the crystal film formation of the magnetic films. Further, the magnetic characteristics, such as coercive force and squareness ratio, are improved and the high threshold recording density and S/N are obtd. by setting the content of the Z elements in the substrate layer 16 at the above-mentioned range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium, a method for manufacturing the same, and a magnetic disk device using the same, and particularly to a thin film magnetic recording medium suitable for high density magnetic recording, a method for manufacturing the same, and a magnetic field using the same. Disc device

[0002]

2. Description of the Related Art In recent years, downsizing and speeding up of large-scale computers, work stations, personal computers, etc. have been rapidly progressing. As a result, the capacity of the magnetic disk device, which is the external data storage device of the computer, has been increased.
There is an increasing demand for miniaturization and high-speed access. A magnetic recording medium capable of high-density recording is required to improve the performance of the above magnetic disk device. As a medium capable of high-density recording, there is known a magnetic disk having a structure in which an underlayer, a magnetic layer, and a protective layer are sequentially laminated on a nonmagnetic substrate by using a film forming technique such as sputtering.

A magnetic disk of this structure is generally called a thin film medium and has a higher magnetic moment density in the magnetic layer than a coating type medium formed by coating magnetic oxide powder on a disk substrate. It is suitable for high-density magnetic recording because it is easy to increase the coercive force. As a substrate for this type of thin film medium, a non-magnetic disk made of a metal material, an organic resin, ceramics or the like has been conventionally used. In addition, a Ni-P layer, for example, is generally formed in advance as a substrate surface layer on the substrate by a plating method or the like for the purpose of increasing surface hardness and improving magnetic characteristics.

Further, as described in US Pat. No. 4,735,840, fine grooves called a texture may be circumferentially formed on the surface of the Ni-P layer.
This texture formation has an effect of reducing the contact area between the magnetic head and the magnetic recording medium, and suppressing the adhesion of the head to the medium surface when the medium stops rotating. Further, by providing the texture, the magnetic properties such as the coercive force in the circumferential direction of the magnetic film, the squareness ratio, and the residual magnetization amount are improved, and as a result, the resolution and S / N at the time of recording / reproducing are improved. Further, magnetic anisotropy may occur in the surface of the medium depending on the film forming conditions at the time of manufacturing the magnetic recording medium, and the magnetic characteristics may change, but the magnetic characteristics in the circumferential direction are made uniform by the above texture processing, and as a result, Fluctuation of recording / reproducing output (modulation,
(Abbreviated as Md) can be reduced.

Furthermore, as a method of more effectively reducing this modulation, on this substrate (Ni-P
There is also known a method of forming an alloy layer in which Ti or Si is added to Cr as an underlayer on (on the layer). C like this
By alloying the r underlayer, the initial formation layer of the magnetic layer formed thereon has an in-plane isotropic crystal orientation, so that the modulation can be effectively reduced. As a technique related to this type of technology, for example, Japanese Patent Laid-Open No. 63-197.
No. 018 publication is mentioned.

[0006]

As described above, the texturing of the substrate (on the Ni-P layer) and the alloying of the Cr underlayer improve the recording characteristics of the thin film magnetic recording medium and reduce the modulation. The effect changes depending on the microscopic shape and surface composition of 0.1 μm or less on the textured surface. Therefore, in order to create a medium having a uniform magnetic property in the surface with good reproducibility, it is necessary to form a microscopic texture shape uniformly in the surface and control the surface composition with good reproducibility.

However, the texture on a metal substrate is usually
Since it is formed by cutting the disk surface with abrasive grains having a grain size of 0.1 to several μm, it is extremely difficult to uniformly control the surface roughness and pitch of 0.1 to several μm or less in the medium surface. Is. Further, the composition of the substrate surface changes depending on the substrate cleaning method and the storage conditions, so that it is difficult to control it to be constant.

Further, even in the case of a disc using an organic resin or a glass substrate, a circumferential direction or an isotropic texture is formed by polishing the surface with abrasive powder or chemically etching it. It is difficult to uniformly and reproducibly control the microscopic surface shape and surface composition within the medium surface. Therefore, there is a problem in that the recording and reproducing characteristics of the medium vary depending on the modulation and manufacturing lot.

Further, in order to further improve the recording density of the magnetic disk device, the resolution and S / N at the time of recording / reproducing are insufficient in the conventional medium, and it is strongly demanded to develop a medium having more excellent characteristics. It was being done. Also, the composition of the medium,
In-plane magnetic anisotropy is extremely strong depending on process conditions, and modulation may not be able to be reduced even by texturing or under-alloying.Therefore, it is strongly desired to develop a new method for homogenizing magnetic recording characteristics in-plane. Was there.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, and the first object thereof is to provide a magnetic recording medium having uniform magnetic recording characteristics in the plane of the magnetic recording medium and capable of high density recording. The second object is to provide a method for producing such a magnetic recording medium with good reproducibility, and the third object is to provide a large-capacity magnetic disk device using such a magnetic recording medium. To do.

[0011]

As a result of intensive studies conducted by the present inventors on the magnetic characteristics of thin film magnetic recording media, the first object is to provide at least an underlayer, a magnetic layer and a protective layer on a non-magnetic substrate. In a thin film magnetic recording medium in which the first underlayer and the second underlayer are laminated under the magnetic layer to form at least two underlayers. In addition to the above multi-layered structure, at least one element selected from the group of elements of oxygen, fluorine and nitrogen is contained in an atomic percentage of 0.1 to 50% in at least the surface layer portion of the first underlayer. We obtained the knowledge that it can be achieved by urging.

The present invention has been made on the basis of such findings, and the following is a preferred example of the first underlayer. The underlayer is a nonmagnetic layer satisfying the following chemical formula (1). Composed.

[0013]

Embedded image A (1-x) Zx (1) where A is B, Mg, Al, Si, P, Ca, S
c, Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Zn, Ge, Sr, Y, Zr, Nb, Mo, Ru, R
h, Pd, Ag, Cd, In, Sn, Sb, Ba, H
f, Ta, W, Re, Os, Ir, Pt, Au, Tl,
At least one element selected from the element group consisting of Pb and Bi, Z is at least one element selected from the element group consisting of oxygen, fluorine and nitrogen, and x is 0.001 to 0. .50, which is 0.1 to 50 at when converted into atomic percent (hereinafter abbreviated as at%).
%. And, it is more preferably 1 to 20 at%.

In the above chemical formula (1), more preferable A elements are Mg, Al, Ti, V, Cr, Mn and N.
At least one element selected from the group of elements consisting of i, Cu, Zn, Mo and W, and a more preferable Z element is at least one element selected from the group of elements consisting of oxygen and fluorine. It is an element. Then, the preferable thickness of the first underlayer is 1 to 50 n.
m. This first underlayer is made of metal material, organic resin,
A non-magnetic substrate made of ceramics or the like can be uniformly formed with good reproducibility by a known method such as heat treatment, vacuum deposition, sputter deposition, CVD, MBE, or plasma asher.

When forming the first underlayer, the film forming conditions such as reaction gas, target composition, temperature and time are optimized so that the value of x in the chemical formula (1) is in the above range. When the value of x is out of the above range and is below the lower limit, the effect of the first underlayer does not appear, or when it exceeds the upper limit, the crystal orientation of the magnetic layer is changed and the medium The magnetic properties of are significantly deteriorated. Therefore, it is important to adjust the x value within the preferable range, and it is important that at least the surface layer portion of the first underlayer be within this range.

In the present invention, the texturing of the substrate is not a necessary condition, but it is on the substrate (generally a Ni-P plating layer is formed on the surface) before forming the first underlayer according to the conventional method. It is desirable to form a texture in. Further, the first underlayer itself can be textured. Further, in the present invention,
It is also possible to form the disc substrate itself with the material forming the first underlayer. In this case, since the surface of the substrate itself also serves as the first underlayer, there is no need to newly form the first underlayer, and it can be omitted.

As a preferable second underlayer formed on the above-mentioned first underlayer, at least one metal of Cr, Mo and W or at least one of Ti, Si, Fe and V is contained in these metals. It is desirable to use an alloy layer. And a preferable film thickness is 10
~ 500 nm.

As a recording medium, a magnetic layer is further formed on the second underlayer. The magnetic layer is Co.
A base alloy layer, for example, a Co alloy layer containing at least one of Ni, Cr, Zr, Ta and Pt is preferable, and the film thickness is preferably 10 to 100 nm.

A protective layer such as carbon is formed on the magnetic layer to a thickness of 10 to 50 nm, and a lubricating layer such as an adsorbent perfluoroalkylpolyether is further provided, so that the magnetic property in the plane of the recording medium is increased. The recording characteristics are uniform,
A magnetic recording medium that enables high-density recording is obtained.

By using the Cr or Cr alloy layer as the second underlayer and the Co alloy layer as the magnetic layer, the recording / reproducing characteristics of the recording medium can be further improved. Particularly preferred. Also,
If a carbide such as WMoC, a nitride such as SiN, an oxide such as SiO, or B, B ₄ C, MoS ₂ , Rh, or the like is used as the protective layer in addition to the above carbon film, sliding resistance and corrosion resistance are improved. It is preferable because it can be improved.

Further, a first object of the present invention is a thin film magnetic recording medium comprising a non-magnetic substrate and at least an underlayer, a magnetic layer and a protective layer which are sequentially laminated, wherein at least a surface layer portion of the underlayer. Hydrogen to 0.001 to 5 at%
It can also be achieved by a magnetic recording medium containing (atomic percentage). By thus containing a predetermined amount of hydrogen in the underlayer, the magnetic recording characteristics in the surface of the recording medium can be made uniform, and a magnetic recording medium capable of high density recording can be manufactured with good reproducibility.

Further, as described above, the underlayer has at least a first and second laminated structure, and at least the surface layer portion of the first underlayer is at least selected from the group of elements of oxygen, fluorine and nitrogen. One element 0.1 to 50 at
% Of hydrogen and 0.001 to 5a of hydrogen in one or both of the first and second underlayers.
A magnetic recording medium containing t% may be used, and in this case, the magnetic recording characteristics in the medium surface are more uniform, which is more preferable.

The film forming conditions such as ultimate vacuum, evacuation method, gas composition, target composition, temperature and time are optimized so that the value of the hydrogen concentration falls within the preferable range. If the hydrogen concentration value is below the above lower limit value, no sufficient effect is exhibited, and if the hydrogen concentration value is above the upper limit value, the crystal orientation of the magnetic layer changes and the magnetic properties of the medium deteriorate significantly.

A second object of the present invention is a method of manufacturing a thin film magnetic recording medium, which comprises a step of sequentially laminating at least an underlayer, a magnetic layer and a protective layer on a non-magnetic substrate. The forming step includes a plurality of underlayer forming steps of laminating a second underlayer on at least the first underlayer, and in the first underlayer forming step, at least the surface layer portion contains oxygen and fluorine. And at least one element selected from the element group of nitrogen.
It is achieved by a method for manufacturing a magnetic recording medium, which comprises a forming step of containing 1 to 50 at%. A Ni-P plating layer is usually formed on the surface of the non-magnetic substrate in advance, and it is desirable to perform texture processing.
However, in the present invention, texturing is not always necessary and can be omitted.

Another method is a method of manufacturing a thin film magnetic recording medium, which comprises a step of sequentially laminating at least an underlayer, a magnetic layer and a protective layer on a non-magnetic substrate, the underlayer forming step. Has a plurality of underlayer forming steps of laminating a second underlayer on at least the first underlayer, and in the step of forming the first underlayer, oxygen, fluorine and nitrogen elements are present in at least the surface layer portion. 0.1 to at least one element selected from the group
A forming step containing 50 at% and hydrogen of 0.001
And a forming step in which the content of the magnetic recording medium is 5 at%.

A third object of the present invention is to provide a magnetic disk comprising a magnetic recording medium, a rotary drive unit for the magnetic recording medium, a magnetic head, a magnetic head drive unit, and a recording / reproducing signal processing system. An apparatus, which is achieved by configuring the magnetic recording medium as a magnetic recording medium capable of achieving the first object.

In this magnetic disk device, a magnetic disk device having a large capacity can be obtained by further combining the above magnetic recording medium with a magnetic head having a track width of 12 μm or less, which is compatible with high density recording such as a thin film magnetic head. Can be realized.

[0028]

As described above, at least the surface layer of the first underlayer contains 0.1 to 50 at% of at least one element selected from the group of elements of oxygen, fluorine and nitrogen, and The composition can be made uniform with good reproducibility. As a result, crystal nuclei are uniformly formed in the medium plane in the initial stage of crystal growth of the second underlayer film and magnetic film, and the crystallinity and orientation of the second underlayer film and magnetic film are uniform in the medium plane. Electron beam diffraction, RHEED, X
It became clear by the line diffraction method.

When a first underlayer containing, for example, a constant concentration of oxygen is formed on the substrate, the magnetic characteristics should be uniform within the medium surface without being affected by the microscopic shape of the surface. Was clarified by analysis using STM, TEM, RHEED, X-ray diffraction method and the like. Furthermore, the chemical formula (1)
By setting the x value of the composition indicated by the above in the above preferable range, the magnetic characteristics such as the coercive force and the squareness ratio are improved, and a high limit recording density and S / N can be obtained. In other words, it is possible to form a medium with high magnetic properties, which is uniform in the plane of the medium and which enables high-density recording with good reproducibility. The above effect is similarly confirmed when the first underlayer containing nitrogen and / or fluorine at a constant concentration is formed.

Further, the above effect is similarly confirmed when hydrogen is contained in the underlayer and / or the magnetic layer in an amount of 0.001 to 5 at%.

On the other hand, conventional metal materials and organic resins,
When a non-magnetic substrate such as ceramics is used, it is difficult to control the microscopic surface shape and composition of the substrate surface to a constant level, as described above. Nucleation becomes non-uniform on the surface of the medium, and magnetic characteristics easily fluctuate and reproducibility is low. When the value of x in the chemical formula (1) is out of the above preferable range, the crystallinity of the second underlayer film or the magnetic film is deteriorated, so that the magnetic characteristics of the magnetic recording medium are deteriorated and the high limit recording density or S / N cannot be obtained.

Further, the hydrogen concentration in the underlayer and / or the magnetic layer is partially different in the range of preferable content, but if it is out of the above range, the characteristics are deteriorated. In particular, when the upper limit of 5 at% is exceeded, the crystallinity of the underlayer film and the magnetic film is remarkably deteriorated, so that the magnetic characteristics of the medium are deteriorated and a high limit recording density and S / N cannot be obtained. Therefore, when hydrogen is introduced, it behaves quite differently compared to oxygen, fluorine, and nitrogen, and it is important to control the composition of this upper limit.

The effect of the first underlayer is that the magnetic layer is made of, for example, CoNi, CoCr, CoFe, CoMo, CoW,
Any Co-based alloy such as CoPt and CoRe can be effectively recognized. Further, taking the corrosion resistance of the magnetic layer into consideration, CoNiZr, CoCrPt, CoCrTa,
It is more desirable to use an alloy containing CoNiCr as a main component.

Further, as the second base film, a group of Cr, W and Mo or this group and Si, Ti,
Similar effects can be observed when alloys with Fe and V groups are used, but Cr or Cr alloys are particularly preferable. As the substrate, an aluminum alloy such as Al-Mg, chemically strengthened glass, organic resin, or more preferably Ni-P, Ni-WP, Ni-V on these substrates.
It is effective to form a non-magnetic plating layer made of, for example,

As the protective film, C, B, B ₄ C, SiC,
A nonmagnetic coating layer made of SiO ₂ , Si ₃ N ₄ , WC, WMoC, WZrC or the like is preferable and effective.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENT A typical embodiment of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 shows an embodiment of the present invention.
FIG. 3 is a vertical cross-sectional view of a thin film magnetic disk in which magnetic recording media are formed on both surfaces of a non-magnetic substrate. In this example, a first underlayer contains oxygen. 1 in the figure
Reference numeral 1 is a non-magnetic substrate, which is made of Al-Mg alloy, chemically strengthened glass, organic resin, ceramics, or the like. 1
Reference numerals 2 and 12 'are non-magnetic plating layers made of Ni-P, Ni-WP, etc. When an Al-Mg alloy is used as a substrate, a substrate on which this plating layer is formed is usually used.

Reference numerals 13 and 13 'are second underlayers, and C
It is composed of any one of r, Mo, W or Cr alloy, Mo alloy and W alloy. 14 and 14 'are magnetic layers, and C
oNi, CoCr, CoRe, CoPt, CoP, Co
Fe, CoNiZr, CoCrZr, CoCrTa, C
oCrPt, CoNiCr, CoNiTi, CoNi
It is made of a Co-based alloy such as P, CoNiPt, CoNiHf.

Numerals 15 and 15 'are protective layers, and are C, B and B.
₄ C, SiC, SiO ₂ , Si ₃ N ₄ , WC, WMoC, W
It is composed of a non-magnetic coating layer such as ZrC. And 16, 1
Reference numeral 6'denotes a first underlayer, which is a characteristic part of this embodiment, and is composed of the nonmagnetic layer represented by the chemical formula (1) shown above. Hereinafter, the manufacturing process of this example will be described in detail.

First, on both surfaces of an Al-4% Mg alloy substrate 11 having an outer diameter of 130 mm, an inner diameter of 40 mm and a thickness of 1.9 mm,
Ni-12 wt% P layers 12 and 12 ′ having a film thickness of 20 μm were formed by plating. The surface of the Ni-P layer was polished in a substantially circumferential direction (head traveling direction) until the film thickness became 15 μm to form a texture, which was used as a substrate.

This non-magnetic substrate was placed in an oxygen stream at 100-2.
Heat treatment was performed at 00 ° C. to form first underlayers 16 and 16 ′ containing oxygen in a surface layer portion of Ni—P with a film thickness of 5 to 10 nm. The oxygen concentration x defined by the chemical formula (1) can be obtained without taking out the disk substrate on which the first underlayer is formed into the air.
Were analyzed by Auger electron spectroscopy or secondary ion mass spectrometry.

Subsequently, using a magnetron sputtering device on the first underlayer, the substrate temperature was 150 ° C., the input power was 3 W / cm ² , and the argon pressure was 5 mTorr.
A 50 nm-thickness Cr layer to be the second base films 13 and 13 'was formed. The magnetic layers 14, 14 'are formed on the second underlayer film.
As a film thickness of 60 nm, Co-12 at% Cr-4 at%
The Ta layer was laminated. A 20 nm-thick carbon protective film 15, 15 ′ is laminated on this magnetic film by a similar sputtering device, and a lubricating layer (not shown) made of adsorbable perfluoroalkyl polyether or the like is further provided on the protective film. It was

The recording / reproducing characteristics of the magnetic recording medium thus formed were measured at a relative velocity of 12 m / s and a floating spacing of 0.1.
At 2 μm, a thin film magnetic head having an effective gap length of 0.3 μm and a track width of 10 μm was used to measure the modulation (Md), the limit recording density (D ₅₀ ), and the S / N value. The modulation is Md = (HL) / (H +) depending on the maximum output H and the minimum output L in the medium plane.
L) × 100%.

Table 1 shows changes in oxygen concentration x, Md, D ₅₀ and S / N when the heat treatment time of the substrate was changed. In addition,
Table 1 also shows the recording / reproducing characteristics of the conventional example in which the first underlayer 16 is not provided as a comparative example. This comparative example was similarly used in all the examples described below unless otherwise specified.

[0044]

[Table 1]

As is clear from Table 1, the value of x is 0.0
When it was 008 to 0.50, Md decreased and D ₅₀ and S / N values improved. Furthermore, the film thickness of the first underlayer containing oxygen is changed to 1 n by changing the heat treatment temperature and time of the non-magnetic substrate.
Even when the thickness was changed from m to 50 nm, the same effect of improving the magnetic characteristics as in Table 1 was confirmed.

Example 2 By the same procedure as in Example 1, the surface of the Al—Mg alloy substrate plated with the Ni—P layer was polished to form a texture, which was used as a substrate. A first underlayer 16, 16 ′ containing a predetermined amount of oxygen is formed on the non-magnetic substrate by a magnetron sputtering device using a Cr target as the A element in the chemical formula (1) and a mixed gas of oxygen and argon.
To a film thickness of 5 to 10 nm. At that time, the substrate temperature is set to 15
The input power was set at 0 ° C. and 3 W / cm ² . Other A elements such as Mg, Al, Si, Ca, Sc, T
i, V, Mn, Fe, Co, Ni, Cu, Zn, Ge,
Sr, Y, Zr, Nb, Mo, Ru, Rh, Pd, A
g, Cd, In, Sn, Sb, Ba, Hf, Ta, W,
In the same manner, at least one element selected from the group of elements consisting of Re, Os, Ir, Pt, Au, Tl, Pb and Bi is used to form the first underlayer 16 or 16 'containing a predetermined amount of oxygen. A film thickness of 5 to 10 nm was formed.

The value of the oxygen concentration x in the first underlayer was analyzed by Auger electron spectroscopy or secondary ion mass spectrometry without taking out the substrate on which the first underlayer was formed into the air, The oxygen gas partial pressure during film formation was controlled so that the value of x was in the range of 0.001 to 0.50 (0.1 to 50 at% in terms of atomic%). On the first underlayer, the second underlayer films 13, 13 'containing Cr as in Example 1 are provided.
Co-12 at% Cr-4 at% Ta magnetic film 14, 1
4 ′ and carbon protective films 15 and 15 ′ were sequentially laminated. Furthermore, a thin film magnetic recording medium was completed by providing a lubricating layer made of an adsorbent perfluoroalkyl polyether or the like on the protective film.

The recording / reproducing characteristics of the medium thus formed were measured in the same manner as in Example 1, and the modulation (Md),
Limit recording density (D ₅₀ ) and S / N values were determined, and the results are shown in Table 2. In Table 2, the first underlayer 16,
16 'is Mg, Al, Ti, V, Cr, Mn, N
Oxygen concentration x, Md, D ₅₀ , S when a film is formed using an i, Cu, Zn, Zr, Nb, Mo, Ta, W target.
The value of / N is shown.

[0049]

[Table 2]

As is clear from Table 2, the value of x is 0.0
Although the values are 08 to 0.41 (0.8 to 41 at%), the Md was decreased and the D ₅₀ and S / N values were improved in comparison with the comparative examples. Although not illustrated in Table 2, Si, Ca, Sc, Fe, C are used as the first underlayer forming target.
o, Ge, Sr, Y, Ru, Rh, Pd, Ag, Cd,
In, Sn, Sb, Ba, Hf, Re, Os, Ir, P
Using t, Au, Tl, Pb, and Bi, the value of the oxygen concentration x in the first underlayer is 0.001 to 0.50 (0.1 to 50).
(at%) even when set to the range of Md = 6%
Below, D ₅₀ = 29 kFCI or more and S / N = 6.5 or more, and in both cases, Md was decreased and the values of D ₅₀ and S / N were improved as compared with the comparative example.

In the above example, a target having a single composition was used at the time of forming the first underlayer, but a target containing two or more of the above elements was used, and a film thickness of 5 was obtained under the same conditions as above. A first underlayer of 10 nm was formed. Also in this case, it was confirmed that the same effect of improving the magnetic properties as in Table 2 was confirmed, depending on the oxygen concentration, not on the concentration ratio of these two or more elements. Further, when the non-magnetic substrate 11 was a substrate made of organic resin or ceramics instead of the Al—Mg alloy substrate, the same effect of improving the magnetic properties as in Table 2 was confirmed.

<Embodiment 3> As in Embodiment 1, Ni-P
The surface of the Al-Mg alloy substrate 11 plated with the layer 12 was polished to form a texture, which was used as a substrate. Using a magnetron sputtering device on this non-magnetic substrate,
Using a Ni target and a target composed of one element selected from the second group consisting of B, C, P, and S, the first method containing oxygen in a thickness of 5 to 10 nm in the same manner as in Example 2 The underlayers 16 and 16 'were formed.

In this first underlayer, the concentration ratio of the element selected from the second group to Ni was set to 5 to 20 at%. Moreover, the value of oxygen concentration x in the first underlayer was analyzed by Auger electron spectroscopy or secondary ion mass spectrometry, and the value of x was 0.001 to 0.50 (0.1 to 50 at).
%) Was controlled so that the partial pressure of oxygen gas during film formation was within the range. Then, C was formed on the first underlayer in the same manner as in Example 1.
The second base films 13 and 13 'containing r are coated with C
Magnetic films 14, 1 of o-12 at% Cr-4 at% Ta
4 ', and the carbon protective films 15, 15' were further laminated thereon. Finally, a lubricating layer (not shown) made of an adsorbent perfluoroalkyl polyether or the like was provided on the protective film.

The recording / reproducing characteristics of the medium thus formed were measured in the same manner as in Example 1, and the modulation (Md),
The limit recording density (D ₅₀ ) and S / N values were determined, and the results are shown in Table 3.

[0055]

[Table 3]

As is clear from Table 3, the oxygen concentration x was 0.008 to 0.25 in the sample in which Ni of the first underlayer contained 5 to 20 at% of B, C, P and S, respectively. Md is decreased also when you were improved D ₅₀ and S / N value. Since B, C, P, and S have an effect of suppressing magnetization of the Ni layer when the first underlayer is made of Ni, it is desirable to contain an appropriate amount.

<Embodiment 4> As in Embodiment 1, Ni-P
The surface of the Al-Mg alloy substrate 11 plated with the layer 12 was polished to form a texture, which was used as a substrate. Using a magnetron sputtering apparatus on this non-magnetic substrate, a fluorine-containing target (including A element forming the first underlayer) and an Ar sputtering gas are used to form the fluorine-containing first underlayer 16, 16 ′. To a film thickness of 5 to 10 nm. The value of the fluorine concentration x in the first underlayer was analyzed by Auger electron spectroscopy or secondary ion mass spectrometry, and the value of x was 0.001 to 0.50 (0.1 to 50 at).
%), The substrate temperature, pressure, and power density were controlled.

On the first underlayer, second underlayers 13 and 13 'containing Cr were formed in the same manner as in Example 1, and a magnetic layer 14 of Co-12 at% Cr-4 at% Ta was formed thereon. 1
4 ', and the carbon protective films 15, 15' were further laminated thereon. Finally, a lubricating layer (not shown) made of an adsorbent perfluoroalkylpolyether or the like was provided on the protective film.

The recording / reproducing characteristics of the medium thus formed were measured in the same manner as in Example 1, and the modulation (Md),
The limit recording density (D ₅₀ ) and S / N values were determined, and the results are shown in Table 4.

[0060]

[Table 4]

As is clear from Table 4, in this example, when the value of x was 0.008 to 0.50 (0.1 to 50 at%), Md decreased and D ₅₀ and S / N value improved. ..
Although not shown in Table 4, Si, Ca, Sc, Fe, Co, Ge, Sr, Y, R are formed when the first underlayer is formed.
u, Rh, Pd, Ag, Cd, In, Sn, Sb, B
a, Hf, Re, Os, Ir, Pt, Au, Tl, P
b, Bi and a target containing fluorine are used, and the value of the fluorine concentration x in the first underlayer is 0.001 to 0.03.
When set in the range of (0.1-3at%), Md5
% Or less, D ₅₀ 29 kFCI or more, and S / N 6.4 or more, and the characteristics were remarkably improved as compared with the comparative example.

In the above example, a target having a single composition was used when forming the first underlayer, but a target containing two or more of the above elements was used, and a film thickness of 5 was obtained under the same conditions as above. A first underlayer of 10 nm was formed. Also in this case, it was confirmed that the effect of improving the magnetic characteristics was the same as in Table 4, depending on the fluorine concentration, not on the concentration ratio of these two or more elements.

When forming the first underlayer, Ar is used.
When a film is formed using a mixed gas of oxygen and oxygen, and the film thickness of the first underlayer containing fluorine is 5 to 10 nm, the oxygen concentration in the film is set to the range of 0.1 to 3 at%. ,
The same effect of improving the magnetic properties as in Table 4 was confirmed.

Furthermore, the first underlayer is divided into two layers,
The first layer is the first underlayer containing fluorine, and the second layer is the first underlayer containing oxygen and fluorine, and the total thickness is 5 to 10 nm. Although formed in this way, the effect of improving the magnetic characteristics similar to that in Table 4 was confirmed in this case as well. It should be noted that the same effect of improving the magnetic characteristics as in Table 4 was confirmed when a substrate made of organic resin or ceramics was used as the non-magnetic substrate 11 instead of the Al—Mg alloy substrate.

<Embodiment 5> As in Embodiment 1, Ni-P
The surface of the Al-Mg alloy substrate 11 plated with the layer 12 was polished to form a texture, and the substrate was obtained. Using a magnetron sputtering device on this non-magnetic substrate, a target containing nitrogen (including the constituent elements of the first underlayer)
And the Ar sputter gas, the first underlayer 1 containing nitrogen.
6 and 16 'were formed to a film thickness of 5 to 10 nm. The value of nitrogen concentration x in this first underlayer was analyzed by Auger electron spectroscopy or secondary ion mass spectrometry, and the value of x was 0.00
The substrate temperature, pressure, and power density were controlled so as to be in the range of 1 to 0.50 (0.1 to 50 at%).

C was formed on the first underlayer in the same manner as in Example 1.
The second base films 13 and 13 'containing r are coated with C
Magnetic films 14, 1 of o-12 at% Cr-4 at% Ta
4 ', and the carbon protective films 15 and 15' were sequentially laminated on the 4 '. Finally, a lubricating layer made of adsorbent perfluoroalkylpolyether or the like was provided on this protective film to complete a thin film magnetic recording medium.

The recording / reproducing characteristics of the medium thus obtained were measured in the same manner as in Example 1 to obtain the values of modulation (Md), limit recording density (D ₅₀ ), and S / N. The results are shown in Table 5 as values of fluorine concentration x, Md, D ₅₀ and S / N when the metal element in the target was changed.

[0068]

[Table 5]

As is clear from Table 5, the value of x is 0.0
09-0.25, Md decreased, D ₅₀ and S /
Both N values have improved.

Although not shown in Table 5, when forming the first underlayer 16, 16 ', Si, Ca, Sc,
Fe, Co, Ge, Sr, Y, Ru, Rh, Pd, A
g, Cd, In, Sn, Sb, Ba, Hf, Re, O
Using a target containing s, Ir, Pt, Au, Tl, Pb, Bi and nitrogen, the value of nitrogen concentration x in the film is 0.0
When set in the range of 1 to 0.3 (0.1 at% to 3 at%), Md = 6% or less, D ₅₀ = 29 kFCI or more,
The S / N was 6.4 or more, showing a marked improvement in characteristics as compared with the comparative example.

In the above example, a target having a single composition was used when forming the first underlayer, but a target containing two or more of the above elements was used, and a film thickness of 5 was obtained under the same conditions as above. A first underlayer of 10 nm was formed. Also in this case, it was confirmed that the same effect of improving the magnetic characteristics as in Table 5 was obtained, depending on the nitrogen concentration, not on the concentration ratio of these two or more elements.

When forming the first underlayers 16 and 16 ′, a mixed gas of Ar and oxygen is used to form the film, and the oxygen concentration in the film is set to a range of 0.1 to 3 at%. As well as
The film thickness of the first underlayer containing nitrogen is 5 to 10 nm.
Although formed, in this case as well, the same effect of improving the magnetic properties as in Table 5 was confirmed.

Furthermore, the first underlayer is divided into two layers, the first underlayer is the first underlayer containing nitrogen, and the second underlayer is the second underlayer containing oxygen and nitrogen. Was formed to a film thickness of 5 to 10 nm. In this case as well, the effect of improving the magnetic characteristics similar to that in Table 5 was confirmed. It should be noted that the same effect of improving the magnetic properties as in Table 5 was confirmed even when a substrate made of organic resin or ceramics was used as the non-magnetic substrate 11 instead of the Al—Mg alloy substrate.

<Embodiment 6> As in Embodiment 1, Ni-P
The surface of the Al-Mg alloy substrate plated with the layer 12 was polished to form a texture, which was used as the substrate. Using a magnetron sputtering device on this non-magnetic substrate, a target containing the constituent elements of the first underlayer and nitrogen and C
The film thickness is 5 to 1 by Ar sputtering gas containing F _4.
A first underlayer containing 0 nm of nitrogen and fluorine was formed.

The value of the total concentration x of nitrogen and fluorine in the first underlayer was analyzed by Auger electron spectroscopy or secondary ion mass spectrometry, and the value of x was 0.001 to 0.50.
The substrate temperature should be in the range of (0.1 to 50 at%),
The pressure and power density were controlled.

On the first underlayer, the second underlayer films 13 and 13 'containing Cr as in Example 1 and C on the second underlayer films 13 and 13'.
Magnetic films 14, 1 of o-12 at% Cr-4 at% Ta
4 ', and further carbon protective films 15 and 15' were sequentially laminated thereon. Finally, a lubricating layer (not shown) made of adsorbable perfluoroalkyl polyether or the like is formed on this protective film.
Was established.

The recording / reproducing characteristics of the thin film magnetic recording medium thus formed were measured in the same manner as in Example 1, and the values of modulation (Md), limit recording density (D ₅₀ ) and S / N were obtained. The results are shown in Table 6, where the total concentration x, Md of nitrogen and fluorine when the metal element in the target was changed,
The values are shown as D ₅₀ and S / N.

[0078]

[Table 6]

As is clear from Table 6, the value of x is 0.0
At 08 to 0.50 (0.1 to ₅₀ at%), Md decreased, and both D ₅₀ and S / N value improved. In particular, x
When the value of was 0.01 to 0.15 (1 to 15 at%), Md was further decreased, and higher D ₅₀ and S / N values were obtained.

Although not shown in Table 6, Si, Ca, Sc, Fe, Co, Ge, and S are formed when the first underlayer is formed.
r, Y, Ru, Rh, Pd, Ag, Cd, In, Sn,
Sb, Ba, Hf, Re, Os, Ir, Pt, Au, T
Using a target of 1, Pb and Bi, the value of the total concentration x of nitrogen and fluorine in the film was 0.008 to 0.25 in the same manner.
When set in the range of (0.8 to 25 at%), M
d = 6% or less, D ₅₀ = 29 kFCI or more, S / N = 6.
It was 3 or more, and the characteristics were remarkably improved as compared with the comparative example.

In the above example, a target having a single composition was used when forming the first underlayer, but a target containing two or more of the above elements was used, and a film thickness of 5 was obtained under the same conditions as above. A first underlayer of 10 nm was formed. In this case as well, it was confirmed that the same effect of improving the magnetic properties as in Table 6 was confirmed, depending on the concentrations of nitrogen and fluorine, not on the concentration ratio of these two or more elements.

As in the above example, a film was formed by using a mixed gas of Ar and oxygen, and the oxygen concentration in the film was 0.1 to 3 at.
The first underlayer containing nitrogen and fluorine set in the range of 5% was formed to a film thickness of 5 to 10 nm. In this case as well, the effect of improving the magnetic characteristics similar to that in Table 6 was confirmed.

Furthermore, the first underlayer is divided into two layers, the first layer is a first underlayer containing nitrogen and fluorine, and the second layer is formed on the first underlayer containing oxygen, nitrogen and fluorine. An underlayer containing Al was formed to a film thickness of 5 to 10 nm, and in this case as well, the effect of improving magnetic characteristics similar to that in Table 6 was confirmed. It should be noted that the same effect of improving the magnetic characteristics as in Table 6 was confirmed even when a substrate made of organic resin or ceramics was used as the non-magnetic substrate 11 instead of the Al—Mg alloy substrate.

<Embodiment 7> As in Embodiment 1, Ni-P
The surface of the Al-Mg alloy substrate 11 plated with the layer 12 was polished to form a texture, and the substrate was obtained. Using a magnetron sputtering device on this non-magnetic substrate, Ni ₁₀ C
Using a r ₉₀ alloy target and a mixed gas of oxygen and hydrogen (which can be introduced by steam) and argon, the first underlayers 16 and 16 ′ containing oxygen and hydrogen are formed with a film thickness of 5 to 5
10 nm was formed. At that time, the substrate temperature was set to 150 ° C. and the input power was set to 3 W / cm ² . The values of oxygen concentration x and hydrogen concentration y in this first underlayer are determined by photoelectron spectroscopy or Auger electron spectroscopy, secondary ion mass spectrometry, CHN.
Analyzed by analysis method, mass spectrometry method, etc., oxygen concentration is x =
Has a hydrogen content of 0.013 and at the same time a hydrogen concentration of y = 0.0000
Ultimate vacuum or evacuation speed, evacuation method by turbo molecular pump, Ar gas purity, oxygen gas partial pressure during film formation, and hydrogen so as to have a value in the range of 1 to 0.05 (0.001 to 5 at%) The gas partial pressure was controlled respectively.

On the first underlayers 16, 16 ', the second underlayer films 13, 13' containing Cr as in Example 1 are formed.
On top of them, Co-12 at% Cr-4 at% Ta magnetic films 14 and 14 ′, and carbon protective film 1 on top of them.
5, 15 'were sequentially laminated.

At this time, the average hydrogen concentration in the second underlayer films 13 and 13 'and the magnetic films 14 and 14' is y = 0.000.
Ultimate vacuum or evacuation speed, evacuation method using turbo molecular pump, Ar gas purity during formation, oxygen gas partial pressure, hydrogen so as to have a value in the range of 01 to 0.05 (0.001 to 5 at%) The gas partial pressure was controlled respectively. Finally, a lubricating layer (not shown) made of an adsorptive perfluoroalkyl polyether or the like was provided on the carbon protective films 15 and 15 'to complete the thin film magnetic recording medium.

The recording / reproducing characteristics of the medium thus formed were measured in the same manner as in Example 1, and the modulation (Md),
The limit recording density (D ₅₀ ) and the value of S / N were obtained. The results are shown in Table 7 as the average hydrogen concentration y, Md, D ₅₀ and S / N value in the first and second underlayer films and the magnetic film.

[0088]

[Table 7]

As is clear from Table 7, the value of hydrogen concentration y is 0.0001 to 0.05 (0.001 to 5 at%).
In M, the Md decreased and the values of D ₅₀ and S / N were improved, and good results were obtained.

A second underlayer film is formed directly on the substrate without forming the first underlayer layers 16 and 16 ', and the average hydrogen concentration in the second underlayer film and the magnetic film is 0. .001
Ultimate vacuum or pumping speed so that it becomes ~ 5at%,
When the exhaust method using a turbo molecular pump or the like, the Ar gas purity, and the oxygen gas partial pressure during film formation were controlled, Md = 1%, D
₅₀ = 31 kFCI or more and S / N = 6.7 or more, Md decreased compared to the comparative example, and D ₅₀ and S / N values also improved.

<Embodiment 8> The steps are the same as those in Embodiment 7, except that the second undercoating film is formed directly on the substrate without forming the first undercoating layers 16 and 16 ', and the ultimate vacuum is achieved. Temperature or exhaust rate, exhaust method using a turbo molecular pump, Ar gas purity, and oxygen gas partial pressure during film formation are controlled, and hydrogen in the second underlayer and magnetic film has an average concentration of 0.00
A thin film magnetic recording medium was manufactured by containing 1 to 5 at%. The characteristics of this medium are Md = 1% and D ₅₀ = 31.
kFCI or more and S / N = 6.7 or more, the Md was decreased, and the values of D ₅₀ and S / N were improved as compared with the comparative example containing no hydrogen. This example is the effect of hydrogen doping as described above, and the first underlayer containing oxygen, fluorine, nitrogen, etc. is omitted.

<Embodiment 9> Four thin film magnetic recording media of the present invention produced in each of Embodiments 1 to 8 were incorporated into a magnetic disk device, and a recording / reproducing test was conducted. As for the device configuration,
A known device was used in which seven thin-film magnetic heads each having a magnetic pole material of CoTaZr alloy were combined. As shown in the cross-sectional view of FIG. 2, this device is composed of components such as a magnetic recording medium 21, a rotation driving unit 22 of the magnetic recording medium, a magnetic head 23, a magnetic head driving unit 24, and a recording / reproducing signal processing system 25. ..

In this magnetic disk device, the recording medium 21
The fluctuation of the magnetic characteristics during the period was reduced to 1/3 of the conventional one, and the modulation was reduced to 1/2. Furthermore, the recording density is 1.
The size can be increased five times, and a compact magnetic disk device can be realized as compared with the conventional device. Further, in the present embodiment, the case of using the thin film magnetic head using CoTaZr alloy as the magnetic pole material has been described, but in addition to the case of using the thin film magnetic head using NiFe, CoFe alloy or the like as the magnetic pole material,
Similar effects were obtained even when a metal-in-gap type (MIG) magnetic head having a gap portion made of Zr, FeAlSi alloy, or the like was used.

[0094]

As described above, according to the present invention, it is possible to realize a magnetic recording medium capable of high density recording, a manufacturing method thereof, and a small-sized and large-capacity magnetic disk device using the same. Was able to achieve the purpose of.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a magnetic recording medium according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a magnetic disk device according to an embodiment of the present invention.

[Explanation of symbols]

11 ... Base, 12, 12 '
... Non-magnetic plating layer, 13, 13 '... Second underlayer,
14, 14 '... magnetic layer, 15, 15' ... protective layer,
16, 16 '... First underlayer 21 ... Magnetic recording medium, 22 ... Rotation drive unit of magnetic recording medium, 23 ... Magnetic head,
24 ... Magnetic head drive unit, 25 ... Recording / reproducing signal processing system.

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Tomio Yamamoto 1-280, Higashi Koikeku, Kokubunji City, Tokyo Metropolitan Research Center, Hitachi, Ltd. (72) Inventor Yasuo Yaku 1-280, Higashi Koikeku, Kokubunji, Tokyo Hitachi Ltd. (72) Inventor, Tadashi Ono 1-280, Higashi Koigokubo, Kokubunji, Tokyo

Claims (14)

[Claims] 1. A thin-film magnetic recording medium comprising a non-magnetic substrate and at least an underlayer, a magnetic layer and a protective layer sequentially laminated on the non-magnetic substrate, the underlayer being provided on at least a first underlayer and a second underlayer. While having a multi-layered structure in which the formation is laminated, at least one element selected from the group of elements of oxygen, fluorine and nitrogen is present in at least the surface layer portion of the first underlayer in an atomic percentage of 0.1 to 0.1. A magnetic recording medium containing 50%. 2. At least the surface layer portion of the first underlayer,
The magnetic recording medium according to claim 1, comprising a nonmagnetic layer satisfying the following chemical formula (1). Embedded image A (1-x) Zx (1) where A is B, Mg, Al, Si, P, Ca, S
c, Ti, V, Cr, Mn, Fe, Co, Ni, Cu,
Zn, Ge, Sr, Y, Zr, Nb, Mo, Ru, R
h, Pd, Ag, Cd, In, Sn, Sb, Ba, H
f, Ta, W, Re, Os, Ir, Pt, Au, Tl,
At least one element selected from the element group consisting of Pb and Bi, Z is at least one element selected from the element group consisting of oxygen, fluorine and nitrogen, and x is 0.001 to 0. It is 0.50 and is 0.1% to 50% in terms of atomic percentage. 3. A in the chemical formula (1) is replaced with Mg, Al, T
i, V, Cr, Mn, Ni, Cu, Zn, Mo and W
3. At least one element selected from the element group consisting of, and Z is at least one element selected from the element group consisting of oxygen and fluorine.
The magnetic recording medium described. 4. The second underlayer is formed of Cr, Mo and W.
At least one metal or Ti to these metals,
5. The magnetic recording medium according to claim 1, which is composed of an alloy layer containing at least one of Si, Fe and V. 5. A thin-film magnetic recording medium comprising a non-magnetic substrate and at least an underlayer, a magnetic layer and a protective layer, which are sequentially laminated, wherein hydrogen is present in at least a surface layer portion of the underlayer in an atomic percentage of 0.001 to 0.001. A magnetic recording medium containing 5%. 6. The underlayer has a multi-layer structure in which a second underlayer is laminated on at least a first underlayer, and oxygen, fluorine and 6. The magnetic recording medium according to claim 5, wherein at least one element selected from the element group of nitrogen is contained in an atomic percentage of 0.1 to 50%. 7. The thickness of the first underlayer is 1 to 50 nm,
7. The magnetic recording medium according to claim 1, wherein the second underlayer has a thickness of 10 to 500 nm, the magnetic layer has a thickness of 10 to 100 nm, and the protective layer has a thickness of 10 to 50 nm. 8. The magnetic recording medium according to claim 7, wherein the protective layer is formed of a carbon film, and a lubricating layer is formed on the carbon film. 9. The magnetic recording medium according to claim 7, wherein the magnetic layer is composed of a Co-based alloy magnetic film. 10. The Co-based alloy magnetic film is made of Ni, Cr, Z.
8. The magnetic recording medium according to claim 7, which is composed of a Co alloy to which at least one metal element selected from the group of elements consisting of r, Ta and Pt is added. 11. A method of manufacturing a thin-film magnetic recording medium, comprising a step of sequentially laminating at least an underlayer, a magnetic layer and a protective layer on a non-magnetic substrate, wherein at least the underlayer is formed. In addition to having a plurality of underlayer forming steps of stacking a second underlayer on the first underlayer, in the first underlayer forming step, at least the surface layer portion of the element group of oxygen, fluorine and nitrogen 0.1-50 at least one element selected from the atomic percentage
%, A method of manufacturing a magnetic recording medium, which comprises a forming step of containing. 12. A method of manufacturing a thin film magnetic recording medium, comprising a step of sequentially forming at least an underlayer, a magnetic layer and a protective layer on a non-magnetic substrate, wherein at least the underlayer forming step is performed. In addition to having a plurality of underlayer forming steps of laminating a second underlayer on one underlayer, in the first underlayer forming step, at least the surface layer portion thereof contains an element group of oxygen, fluorine and nitrogen. 0.1-50% in atomic percent of at least one element selected from
Forming step to contain and hydrogen in atomic percent of 0.
001 to 5% forming step, and a method for manufacturing a magnetic recording medium. 13. The method of manufacturing a magnetic recording medium according to claim 11, wherein a Ni—P plating layer is previously formed on the non-magnetic substrate and a texture processing step is performed. 14. A magnetic disk device comprising a magnetic recording medium, a magnetic recording medium rotation drive section, a magnetic head, a magnetic head drive section, and a recording / reproducing signal processing system.
A magnetic disk device comprising the magnetic recording medium according to claim 1.