JP2002334424A - Magnetic recording medium, method for manufacturing the same and magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording medium in which the crystal orientation of the magnetic film can be increased and the magnetic particles can be made fine, and to provide a method for manufacturing the medium and a magnetic recording and reproducing device. SOLUTION: A soft magnetic base film 2, orientation controlling film 4, perpendicular magnetic film 5 and protective film 6 are formed on a nonmagnetic substrate 1. The orientation controlling film 4 consists of an alloy containing a first element and a second element which can form a solid solution with the first element. The first element is Ru and/or Re while the second element has the solid solution limit with the first element and does not form the hcp structure as a single crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic recording medium, a method for manufacturing the same, and a magnetic recording / reproducing apparatus using the magnetic recording medium.

[0002]

2. Description of the Related Art Conventionally, an in-plane magnetic recording medium in which an easy axis of magnetization in a magnetic film is mainly oriented parallel to a substrate has been widely used. In an in-plane magnetic recording medium, it is necessary to reduce noise in order to achieve high recording density. However, if the size of magnetic particles is reduced for noise reduction, the volume of the particles is reduced. As a result, the reproduction characteristics are likely to deteriorate due to the thermal fluctuation. In addition, when the recording density is increased, medium noise may increase due to the influence of a demagnetizing field at a recording bit boundary. On the other hand, a so-called perpendicular magnetic recording medium in which the easy axis of magnetization in the magnetic film is mainly oriented perpendicular to the substrate has a small effect of the demagnetizing field at the bit boundary even when the recording density is increased, and the boundary is small. Since a clear recording magnetic domain is formed, thermal fluctuation characteristics and noise characteristics can be enhanced, examples of perpendicular magnetic recording media that have received great attention include JP-A-60-214417 and JP-A-60-214417. 63-111117. For the perpendicular magnetic film of the perpendicular magnetic recording medium, usually, a Co alloy such as a CoCr alloy capable of increasing magnetic anisotropy is used. Co on the non-magnetic substrate directly
When an alloy magnetic film is formed, the crystal orientation of the magnetic film deteriorates, and the grain size of the columnar crystals becomes non-uniform, so that by providing a base film between the non-magnetic substrate and the perpendicular magnetic film,
Attempts have been made to improve the crystal orientation (C-axis orientation) of the magnetic film. It has been reported that the hexagonal close-packed structure material such as Ti can easily improve the orientation of a Co alloy magnetic film by using this as a base film because the crystal is easily oriented to (0001). For perpendicular magnetic recording media using a Ti-containing underlayer, see IEEE Transacti
ons on Magnetics MAG., 19 (1983) 1644. Japanese Patent Publication No. 7-101495 proposes a method of improving the C-axis orientation of a Ti-containing base film and a Co alloy magnetic film by providing a film made of Si, Ge, Sn or the like under a Ti-containing base film. Have been. Patent No. 26695
No. 29 discloses a technique for improving the lattice alignment between a base film and a Co alloy magnetic film and improving the crystal orientation of the Co alloy magnetic film by adding another element to the Ti-containing base film. Has been proposed.

[0003]

In recent years, in order to improve the magnetic characteristics of a perpendicular magnetic recording medium and achieve a higher recording density, it has been desired to increase the reproduction output and reduce noise. However, in the above-mentioned conventional magnetic recording medium, the crystal orientation is likely to be insufficient, and it is difficult to make the magnetic particles finer, so that at present, sufficient magnetic characteristics cannot be obtained. In particular, when the thickness of the underlayer is reduced to reduce the crystal grains, the crystal grains of the underlayer become non-uniform due to the influence of the initial growth layer, and the crystal orientation of the perpendicular magnetic film may deteriorate. Was. In recent years, a soft magnetic underlayer (a so-called backing layer) made of a soft magnetic material is provided between a perpendicular magnetic film and a substrate.
There has been proposed a magnetic recording medium in which the efficiency of moving a magnetic flux between a magnetic head and a magnetic recording medium is improved. In this magnetic recording medium, at the time of recording and reproduction, the magnetic flux from the magnetic head forms a closed magnetic path passing through the perpendicular magnetic film and the soft magnetic underlayer, so that the efficiency of the entry and exit of the magnetic flux increases, and high-density recording and reproduction is performed. Becomes possible. However, in the conventional magnetic recording medium, the crystal orientation of the perpendicular magnetic film is insufficient and the magnetic anisotropy is inferior, so the closed magnetic path tends to be unstable, and the recording / reproducing characteristics, thermal fluctuation characteristics, recording resolution, etc. There was a problem that was likely to be insufficient. The present invention has been made in view of the above circumstances, and provides a magnetic recording medium capable of improving the crystal orientation of a magnetic film and miniaturizing magnetic particles, a method for manufacturing the same, and a magnetic recording / reproducing apparatus. With the goal.

[0004]

The magnetic recording medium of the present invention controls the orientation of a soft magnetic underlayer made of at least a soft magnetic material, an orientation control underlayer, and a film directly above a nonmagnetic substrate. An orientation control film, a perpendicular magnetic film whose easy axis is mainly oriented perpendicular to the substrate, and a protective film are provided, and the orientation control film is capable of forming a first element and a solid solution with respect to the first element. An alloy containing a second element, wherein the first element is Ru and / or Re, the second element has a solid solution limit to the first element, and the single crystal does not have an hcp structure. It is characterized by being. As the second element,
V, Nb, Ta, Cr, Mo, W, Mn, Ni, Pd,
At least one selected from Pt and Ir can be mentioned. As a material of the orientation control film, at least one selected from Si oxide, Zr oxide, Hf oxide, Ti oxide, Al oxide, C and B is Ru.
And / or alloys added to Re. The orientation control base film is made of NiAl, FeAl, CoF
e, CoZr, NiTi, AlCo, AlRu, CoT
It is preferable that one or more alloys of i be a main component. The distance between the soft magnetic underlayer and the perpendicular magnetic layer is preferably set to 60 nm or less.

According to the method of manufacturing a magnetic recording medium of the present invention, a soft magnetic underlayer made of at least a soft magnetic material, an orientation control underlayer, and an orientation control film for controlling the orientation of the film immediately above are provided on a nonmagnetic substrate. A method for manufacturing a magnetic recording medium, comprising: a perpendicular magnetic film whose easy axis of magnetization is oriented mainly perpendicular to the substrate; and a protective film, wherein the orientation control film comprises: a first element;
An alloy containing a second element capable of forming a solid solution with the element,
The first element is Ru or Re, the second element has a solid solution limit to the first element, and the single crystal is hcp
It is characterized by having no structure. In the method for manufacturing a magnetic recording medium of the present invention, the orientation control film is formed by converting at least one selected from Si oxide, Zr oxide, Hf oxide, Ti oxide, Al oxide, C, and B with Ru.
And / or an alloy added to Re.

A magnetic recording / reproducing apparatus according to the present invention includes the above-mentioned magnetic recording medium, and a magnetic head for recording / reproducing information on / from the magnetic recording medium.

[0007]

FIG. 1 is a cross-sectional view schematically showing the structure of a magnetic recording medium according to an embodiment of the present invention. As shown in FIG. 1, the magnetic recording medium of the present embodiment is:
On a non-magnetic substrate 1, a soft magnetic under film 2, an orientation control under film 3, an orientation control film 4, a perpendicular magnetic film 5, a protective film 6,
The lubrication film 7 is provided. As the substrate 1, N, which is generally used as a substrate for a magnetic recording medium, is used.
Examples include an aluminum alloy substrate having an iP plating film, a glass substrate (crystallized glass, tempered glass, etc.), a ceramic substrate, a carbon substrate, a silicon substrate, and a silicon carbide substrate. In addition, NiP
A substrate on which a film is formed by a plating method, a sputtering method, or the like can be given. The average roughness Ra of the surface of the substrate 1 is:
0.01 to 2 nm (preferably 0.05 to 1.5 nm)
It is preferable that When the surface average roughness Ra is less than this range, the magnetic head is likely to be attracted to the medium and the magnetic head vibrates during recording and reproduction. If the surface average roughness Ra exceeds this range, the glide characteristics tend to be insufficient.

The soft magnetic underlayer 2 is provided to more firmly fix the magnetization of the perpendicular magnetic film 5 in a direction perpendicular to the substrate 1. As a soft magnetic material constituting the soft magnetic underlayer 2, an Fe alloy containing 60 at% or more of Fe can be used. Examples of this material include FeCo-based alloys (FeCo, FeCoV, etc.) and FeNi-based alloys (FeNi, FeNiMo, FeNiCr, FeNiS
i), FeAl alloys (FeAl, FeAlSi,
FeAlSiCr, FeAlSiTiRu, etc.), Fe
Cr-based alloys (FeCr, FeCrTi, FeCrCu, etc.), FeTa-based alloys (FeTa, FaTaC, etc.),
FeC alloy, FeN alloy, FeSi alloy, FeP
Alloys, FeNb-based alloys, and FeHf-based alloys. The soft magnetic underlayer 2 is made of FeAlO, FeMg
A structure having fine crystals such as O, FeTaN, and FeZrN can be provided. Further, a structure having a granular structure in which the fine crystals are dispersed in a matrix may be employed. In addition to the above, Co is added to
0 at% or more and Zr, Nb, Ta, Cr, M
It is possible to use a Co alloy containing at least one of o and the like. For example, CoZr, CoZrNb,
Suitable examples include CoZrTa, CoZrCr, and CoZrMo. Also, the soft magnetic underlayer 2 may be made of an alloy having an amorphous structure.

The soft magnetic underlayer 2 preferably has a saturation magnetic flux density of 0.8 T or more. If the saturation magnetic flux density is smaller than 0.8T, the reproduced waveform may be disturbed and noise may increase. It is preferable that the coercive force of the soft magnetic underlayer 2 is as small as possible. However, practically, if the coercive force is smaller than 200 (Oe) (15.8 × 10 ³ A / m), sufficient magnetic properties can be obtained. Obtainable.

The thickness of the soft magnetic underlayer 2 is
Is appropriately set in accordance with the saturation magnetic flux density of the material constituting. Specifically, the saturation magnetic flux density Bs (T) of the material constituting the soft magnetic underlayer and the thickness t (nm) of the soft magnetic underlayer 2
It is desirable that Bs · t (T · nm), which is the product of the above, be 40 T · nm or more (preferably 60 T · nm or more).

The surface of the soft magnetic underlayer 2 (the orientation control underlayer 3
The side surface) is preferably formed by partially or completely oxidizing the material constituting the soft magnetic underlayer 2.
The thickness of the oxidized portion (oxide layer) is 0.1 nm or more and 3 nm.
It is preferred to be less than. The oxidized state of the soft magnetic underlayer 2 can be confirmed by Auger electron spectroscopy, SIMS, or the like. The thickness of the oxidized portion (oxide layer) on the surface of the soft magnetic underlayer 2 can be determined, for example, by a transmission electron microscope (TEM) photograph of a cross section of the medium.

The orientation control base film 3 is provided to improve the orientation of the orientation control film 4 and to refine the crystal grains. The material of the orientation control base film 3 is NiAl, FeAl, CoFe, CoZr, NiT
one or two of i, AlCo, AlRu, and CoTi
An alloy containing at least one kind of alloy as a main component can be given. The main component means that the component is contained in excess of 50 at%. In addition, Cr, Nb,
A material to which V, W, Mo, B, O, N, Ru, Nd, or the like is added can also be used. The binary alloy (NiAl,
FeAl, CoFe, CoZr, NiTi, AlCo,
In the case of using AlRu or CoTi), the content of each of the two components constituting the alloy is set to 40 to 60 at.
% (Preferably 45 to 55 at%). As the material of the orientation control base film 3, a material having a B2 structure is preferable. The thickness of the orientation control base film 3 is 0.1
It is preferable to set it to 20 nm. When the alignment control base film 3 has a melting point of 1200 ° C. or more,
This is preferable because the crystal grain size can be reduced.

The orientation control film 4 is a film provided for controlling the orientation and the crystal grain size of the perpendicular magnetic film 5 located immediately above. The orientation control film 4 can be made of an alloy containing Ru and / or Re (hereinafter, sometimes referred to as a first element) and a second element that is soluble in the first element.

The second element is an element capable of forming a solid solution with the first element, but having a solid solution limit (solid solution only in a limited composition range). The second element is an element whose single crystal does not have an hcp structure at room temperature.
As the second element, V, Nb, Ta, Cr, Mo,
At least one selected from W, Mn, Ni, Pd, Pt, and Ir can be mentioned. Table 1 shows the crystal structures of these elements at room temperature, the maximum solid solubility in Ru and Re, and the a-axis length of the elements. Table 1 also shows the single crystal structures of Ru and Re.

[0015]

[Table 1]

As shown in Table 1, the element shown here is R
The solid solubility for u and Re has a limit value (maximum solid solubility). Although the maximum solid solubility of Mn with respect to Re is unknown, it has been confirmed that Mn is an element having a solid solubility limit with respect to Re. Table 1 also shows that the crystal structure of the element shown here does not take the hcp structure.

Specific examples of the alloy used for the orientation control film 4 include Ru-V, Ru-Nb, Ru-Ta, and Ru-C.
r, Ru-Mo, Ru-W, Ru-Mn, Ru-Ni,
Ru-Pd, Ru-Pt, Ru-Ir, Re-V, Re
-Nb, Re-Ta, Re-Cr, Re-Mo, Re-
W, Re-Mn, Re-Ni, Re-Pd, Re-P
t and Re-Ir.

The content of the second element in the alloy constituting the orientation control film 4 is 1 to 50 at% (preferably 1 to 40 at%).
%). If the content is less than the above range, the crystal grain size of the orientation control film 4 becomes large and the magnetic particles in the perpendicular magnetic film 5 are undesirably coarsened. If the second element content exceeds the above range, the orientation of the orientation control film 4 is deteriorated, and the orientation of the perpendicular magnetic film 5 is easily deteriorated. Further, the orientation control film 4 may be made of an alloy containing not only the first and second elements but also other elements as long as the crystal structure of the orientation control film 4 is not deteriorated.

The orientation control film 4 contains at least one selected from the group consisting of Si oxide, Zr oxide, Hf oxide, Ti oxide, Al oxide, C and B as a first element (Ru and / or Alternatively, an alloy added to Re) can be used. Specific examples of this alloy include Ru—SiO ₂ , Ru
_{-ZrO 2, Ru-HfO 2,} Ru-TiO 2, Ru-A
l ₂ O ₃ , Ru-C, Ru-B, Re-SiO ₂ , Re-
ZrO ₂ , Re-HfO ₂ , Re-TiO ₂ , Re-Al ₂
O ₃ , Re-C and Re-B can be mentioned. In the alloy constituting the orientation control film 4, the content of the above materials (at least one of Si oxide, Zr oxide, Hf oxide, Ti oxide, Al oxide, C, and B) is 1 to 3. 50at
% (Preferably 1 to 40 at%). If the content is less than the above range, the crystal grain size of the orientation control film 4 becomes large and the magnetic particles in the perpendicular magnetic film 5 are undesirably coarsened. When the content exceeds the above range, the orientation of the orientation control film 4 is deteriorated, and the orientation of the perpendicular magnetic film 5 is easily deteriorated.

The thickness of the orientation control film 4 is preferably 1 to 50 nm (preferably 1 to 30 nm). If the thickness is less than the above range, the effect of enhancing the crystal orientation of the perpendicular magnetic film 5 tends to be insufficient. If the thickness exceeds the above range, the crystal grain size in the orientation control film 4 becomes large, and the magnetic particles in the perpendicular magnetic film 5 tend to become coarse. In addition, the distance between the magnetic head and the soft magnetic underlayer 2 at the time of recording / reproducing becomes large, so that the resolution of the reproduced signal is lowered and the noise characteristic is deteriorated, which is not preferable. It is preferable that at least the surface (upper surface in the figure) of the orientation control film 4 has an hcp structure.

The perpendicular magnetic film 5 is a magnetic film in which the axis of easy magnetization is oriented mainly perpendicular to the substrate, and it is preferable to use a Co alloy for the perpendicular magnetic film 5. For example, CoC
An rPt alloy or a CoPt alloy can be used. Further, Ta, Zr, Nb, Cu, Re, Ru,
An alloy to which at least one element selected from V, Ni, Mn, Ge, Si, B, O, and N is added can be used.

The perpendicular magnetic film 5 may have a uniform single-layer structure made of the above-mentioned Co alloy.
It may have a multilayer structure in which a layer made of a Co alloy) and a layer made of a noble metal (Pt, Pd, etc.) are stacked. This C
As the o alloy, the above-mentioned CoCrPt-based alloy or CoPt-based alloy can be used. When a CoCrPt-based alloy is used, the Pt content is preferably set to 8 to 24 at% in order to increase the perpendicular magnetic anisotropy. The thickness of the layer made of a noble metal is preferably in the range of 0.4 to 1.4 nm. This is because when the thickness of the noble metal layer is smaller than 0.4 nm, the coercive force Hc and the reverse magnetic domain nucleation magnetic field decrease, and it is difficult to set the layer thickness. When the thickness is larger than 1.4 nm, the noise characteristics deteriorate. To do that. The thickness of the layer made of a transition metal is preferably 0.1 to 0.6 nm (preferably 0.1 to 0.4 nm). If the transition metal layer is too thin, the coercive force Hc and the reverse magnetic domain nucleation magnetic field decrease, and it is difficult to set the thickness. If the transition metal layer is too thick, the noise characteristics deteriorate. In the perpendicular magnetic film 5,
Any of the transition metal layer and the noble metal layer may be the uppermost layer, but the lowermost layer is preferably a noble metal layer.

The constituent materials of the above-mentioned single-layer structure type and laminated structure type magnetic films each have a polycrystalline structure. In the magnetic recording medium of the present invention, a material having an amorphous structure may be used. Specifically, an alloy containing a rare earth element (TbFeC
o-based alloy) can be used.

The thickness of the perpendicular magnetic film 5 may be appropriately optimized depending on the intended reproduction output. However, if the perpendicular magnetic film 5 is too thick, there are problems such as deterioration of noise characteristics and reduction of resolution. 3 to 100 in practice
It is preferably nm. It is preferable that the perpendicular magnetic film 5 has an hcp structure.

The distance between the perpendicular magnetic film 5 and the soft magnetic underlayer 2,
That is, the interval A shown in FIG. 1 is preferably 60 nm or less (preferably 40 nm or less, more preferably 20 nm or less). By setting the interval A within the above range, the closed magnetic path formed between the magnetic head, the perpendicular magnetic film 5 and the soft magnetic underlayer 2 during recording and reproduction is stabilized, the efficiency of magnetic flux entry and exit is increased, and recording and reproduction is performed. Characteristics, thermal fluctuation characteristics, recording resolution, and the like can be improved. If the interval A exceeds the above range, it becomes difficult for the magnetic flux from the magnetic head to reach the soft magnetic underlayer 2 at the time of recording / reproducing, and the above-mentioned characteristics are deteriorated.

The protective film 6 prevents corrosion of the perpendicular magnetic film 5, prevents damage to the medium surface when the magnetic head comes into contact with the medium, and ensures lubrication characteristics between the magnetic head and the medium. It is possible to use a conventionally known material, for example, a single composition of C, SiO ₂ , ZrO ₂ ,
Alternatively, those containing these as main components and containing other elements can be used. It is desirable that the thickness of the protective film 6 be in the range of 1 to 10 nm.

Known lubricants such as perfluoropolyether, fluorinated alcohol, and fluorinated carboxylic acid can be used for the lubricating film 7. The type and thickness can be appropriately set according to the properties of the protective film and the lubricant used.

To manufacture the magnetic recording medium having the above structure,
A soft magnetic underlayer 2 is formed on a substrate 1 shown in FIG. 1 by a sputtering method or the like.
Is subjected to an oxidizing treatment, and then an orientation control base film 3, an orientation control film 4, and a perpendicular magnetic film 5 are sequentially formed by a sputtering method or the like. Next, after forming the protective film 6 by a sputtering method, a CVD method, an ion beam method or the like, a lubricating film 7 is formed by a dip coating method, a spin coating method or the like.

In the case where the surface of the soft magnetic underlayer 2 is subjected to an oxidation treatment, the soft magnetic underlayer 2 is formed and then the soft magnetic underlayer 2 is formed.
May be exposed to an oxygen-containing gas, or a method of introducing oxygen into a process gas when forming a portion near the surface of the soft magnetic underlayer 2. When the surface of the soft magnetic underlayer 2 is exposed to an oxygen-containing gas, the soft magnetic underlayer 2 is exposed to a diluent gas obtained by diluting oxygen with argon or nitrogen or pure oxygen.
The contact may be performed for about 30 seconds. Alternatively, a method of exposing the soft magnetic underlayer 2 to the atmosphere can be adopted. Specifically, 10 ^-4
A preferable oxidation state can be obtained by exposing the surface of the soft magnetic underlayer 2 to an atmosphere having an oxygen gas pressure of 10 ^-3 Pa or more with respect to a degree of vacuum of 10 ^-6 Pa for 0.1 to 30 seconds. When exposing the soft magnetic underlayer 2 to an oxygen-containing gas, the degree of oxidation can be adjusted by appropriately setting the amount of oxygen used and the time of exposure to oxygen. In particular, when a gas obtained by diluting oxygen with a rare gas such as argon is used, the degree of oxidation of the surface of the soft magnetic underlayer 2 can be easily adjusted by setting the dilution ratio of the gas. When oxygen is introduced into the process gas for forming the soft magnetic underlayer 2, for example, a sputtering method is used as the film formation method, and only a part of the film formation time (for example, one second before the completion of the film formation) is performed. A method of performing sputtering using a process gas containing oxygen can be employed. As this process gas, for example, oxygen is added to argon in a volume ratio of 0.1.
Gas mixed with about 05 to 10% is preferably used. By oxidizing the surface of the soft magnetic underlayer 2, the soft magnetic underlayer 2
The magnetic fluctuation of the outermost surface can be suppressed, and the crystal grains of the orientation control base film 3 and the orientation control film 4 formed on the soft magnetic base film 2 can be refined to obtain an effect of improving noise characteristics.
In addition, the function of the oxidized portion on the surface of the soft magnetic underlayer 2 as a barrier layer prevents the corrosive substance from migrating from the soft magnetic underlayer 2 or the non-magnetic substrate 1 to the surface of the medium, thereby preventing the corrosion of the medium surface. it can.

A first element (Ru and / or
Or Re) and the second element (V, Nb, Ta, Cr, M)
When an alloy containing o, W, Mn, Ni, Pd, Pt, Ir, etc.) is used, the orientation control film 4 can be formed by sputtering using a target made of this alloy.

When a first element alloy containing the above oxide (at least one selected from Si oxide, Zr oxide, Hf oxide, Ti oxide and Al oxide) is used for the orientation control film 4. Then, the orientation control film 4 can be formed using a target made of a material containing this oxide and the first element. Alternatively, the orientation control film 4 may be formed using a target made of a material containing at least one of Si, Zr, Hf, Ti, and Al and the first element, and using a process gas containing oxygen.

When the perpendicular magnetic film 5 has a multilayer structure composed of a transition metal layer and a noble metal layer, the transition metal (Co, Co
Alloy) and a noble metal (Pt, Pt)
d), the perpendicular magnetic film 5 is formed by alternately sputtering the material of each target.

The protective film 6 can be formed by a sputtering method using a carbon target, a CVD method, or an ion beam method. RF sputtering using a target of SiO ₂ or ZrO ₂ , or Si or ZrO ₂
With the target, by reactive sputtering using a gas containing oxygen as a process gas, SiO ₂ and ZrO ₂
A method of forming the protective film 6 made of When the CVD method or the ion beam method is used, the protective film 6 having extremely high hardness can be formed, and the film thickness can be significantly reduced as compared with the protective film formed by the sputtering method. Therefore, spacing loss during recording and reproduction can be reduced, and high-density recording and reproduction can be performed.

In the magnetic recording medium of the present embodiment, the orientation control film 4 is made of an alloy containing a first element and a second element which can form a solid solution with the first element, wherein the first element is Ru and / or
Or, it is Re, and the second element has a solid solution limit with respect to the first element, and its single crystal does not have an hcp structure. The crystal orientation of the film 5 can be improved. Further, the crystal grains in the orientation control film 4 are reduced in size,
The magnetic particles can be reduced in the perpendicular magnetic film 5. Therefore, the coercive force can be increased, the reproduction output can be improved, and noise can be reduced.

The reason why excellent magnetic properties can be obtained by forming the orientation control film 4 from an alloy containing the first and second elements can be considered as follows. The second element is an element capable of forming a solid solution with the first element, but having a solid solution limit. further,
The first element is an element in which a single crystal has an hcp structure, while the second element is an element in which a single crystal does not have an hcp structure. As described above, since the second element has different properties from the first element in terms of solid solubility and crystal structure, when the crystal grain grows in the orientation control film 4, the grain boundary where the second element is precipitated is formed. It is considered that a layer is easily formed. Therefore, many uniform crystal grains having a small grain size are formed in the orientation control film 4. The grain boundary layer containing the second element promotes the formation of a grain boundary layer in the perpendicular magnetic film 5 grown under the influence of the orientation control film 4, and fine and uniform magnetic particles are formed in the perpendicular magnetic film 5. . Therefore, the coercive force can be increased, the reproduction output can be improved, and noise can be reduced.

In the orientation control film 4, when a crystal grain grows, the orientation plane of the crystal grain is considered to be affected by the grain boundary layer growing adjacent to the crystal grain. Since this grain boundary layer contains a large amount of the second element, the crystal plane of the crystal grain is
It tends to be constant depending on the type and content of this second element. For this reason, the orientation plane of the crystal grains of the orientation control film 4 becomes uniform. Therefore, the crystal orientation of the perpendicular magnetic film 5 grown under the influence of the orientation control film 4 can be enhanced. Therefore, magnetic characteristics such as coercive force and reproduction output can be further improved.

On the other hand, it has no solid solution limit to the first element (that is, it forms a solid solution over the entire composition) and hc
When an alloy containing an element having a p-structure (for example, Co) is used for the orientation control film 4, this element (for example, Co) becomes the first element.
Since it has properties very similar to the element, it forms a solid solution with no resistance to the first element, so that a grain boundary layer is hardly formed and the crystal grain size tends to be large. Therefore, the magnetic particles in the perpendicular magnetic film 5 tend to be coarse and non-uniform.

Further, at least one selected from the group consisting of Si oxide, Zr oxide, Hf oxide, Ti oxide, Al oxide, C and B is added to Ru and / or Re to the orientation control film 4. By using the alloy thus obtained, the crystal orientation of the orientation control film 4 and the perpendicular magnetic film 5 can be improved. Further, the crystal grains can be reduced in the orientation control film 4 and the magnetic particles can be reduced in the perpendicular magnetic film 5. Therefore, the coercive force can be increased, the reproduction output can be improved, and noise can be reduced.

The reason why excellent magnetic properties can be obtained by using the above alloy for the orientation control film 4 can be considered as follows. The above oxide, C, B
Is a substance that does not form a solid solution with the first element (Ru and / or Re), and is more likely to precipitate in the grain boundary layer than the crystal grains when the crystal grains grow in the orientation control film 4. In the orientation control film 4, a grain boundary layer is easily formed. In addition, the grain boundary layer tends to be wide.
Therefore, many uniform crystal grains having a small grain size are formed in the orientation control film 4. Further, the crystal grains are largely separated from each other. Therefore, increase the coercive force,
It is possible to improve the reproduction output and reduce noise.

In the orientation control film 4, the crystal plane of the crystal grain is formed by the above-mentioned material (the oxide, C,
B) It tends to be constant depending on the type and content. For this reason, the orientation plane of the crystal grains of the orientation control film 4 becomes uniform. Therefore, the crystal orientation of the perpendicular magnetic film 5 grown under the influence of the orientation control film 4 can be enhanced. Therefore, magnetic characteristics such as coercive force and reproduction output can be further improved.

Since the crystal orientation of the perpendicular magnetic film 5 can be improved, the magnetic anisotropy of the perpendicular magnetic film 5 can be increased. For this reason, the closed magnetic path formed between the magnetic head, the perpendicular magnetic film 5 and the soft magnetic underlayer 2 during recording and reproduction is prevented from becoming unstable in the perpendicular magnetic film 5, and a stable closed magnetic path is formed. can do. Therefore, it is possible to increase the efficiency of the magnetic flux in and out, and to improve the recording / reproducing characteristics, the thermal fluctuation characteristics, the recording resolution, and the like.

In this magnetic recording medium, Ru and / or Re are added to the above-mentioned materials (the second element, the above-mentioned oxide,
Since an alloy containing C and B) is used, material costs can be reduced as compared with a case where expensive Ru and / or Re are used alone. Therefore, the manufacturing cost can be reduced.

In this embodiment, the orientation control underlayer 3 made of NiAl or the like is interposed between the soft magnetic underlayer 2 and the orientation control layer 4.
Was provided. Ru alloy, R, which is a constituent material of the orientation control film 4
The e-alloy has a property that the crystal grain size tends to be large. However, in the present embodiment, the crystal of the orientation control film 4 is refined by providing the orientation control base film 3 functioning as a crystal grain refinement film. The crystal grain size of the perpendicular magnetic film 5 formed on the substrate can be reduced. Therefore, it is possible to further reduce noise. It is considered that the provision of the orientation control base film 3 enables the crystal size of the orientation control film 4 to be reduced because the crystal grain size of the orientation control base film 3 (NiAl or the like) is reduced.

Further, Co-based soft magnetic materials (CoZr-based, Co-
ZrNb, CoZrTa, CoZrCr, CoZ
rMo alloys, etc.), Fe soft magnetic materials (FeCo, F
When the orientation control film 4 made of a Ru alloy or a Re alloy is directly formed on the soft magnetic underlayer 2 made of eNi-based, FeAl-based, FeCr-based alloy, etc. Due to the difference in crystallinity with the control film 4, nucleation hardly occurs during the initial growth of the orientation control film 4, and the crystal grain size in the orientation control film 4 tends to be non-uniform. On the other hand, in the present embodiment, since the orientation control base film 3 made of NiAl or the like resembles the orientation control film 4 in terms of crystallinity, nucleation during initial growth of the orientation control film 4 is improved. And uniform crystal grains are easily formed. Therefore, in the present embodiment, by providing the orientation control base film 3, uniform crystal grains having a small grain size are formed in the orientation control film 4, and noise can be further reduced.

In the manufacturing method of this embodiment, the alignment control film 4
In this case, an alloy containing the first and second elements is used.
The crystal orientation of the orientation control film 4 and the perpendicular magnetic film 5 can be improved. Further, the crystal grains can be reduced in the orientation control film 4 and the magnetic particles can be reduced in the perpendicular magnetic film 5. Therefore, the coercive force can be increased, the reproduction output can be improved, and noise can be reduced.

The above-mentioned oxide, C,
By using the first element alloy containing B, the crystal orientation of the orientation control film 4 and the perpendicular magnetic film 5 can be improved, and excellent magnetic anisotropy can be obtained. Further, the crystal grains can be reduced in the orientation control film 4 and the magnetic particles can be reduced in the perpendicular magnetic film 5. Therefore, the coercive force can be increased, the reproduction output can be improved, and noise can be reduced.

As shown in FIG. 2, in the magnetic recording medium of the present invention, a non-magnetic intermediate film 8 made of a non-magnetic material can be provided between the orientation control film 4 and the perpendicular magnetic film 5. For the nonmagnetic intermediate film 8, a Co alloy can be used. As this Co alloy, CoCr can be used. Ta, Zr, Nb, Cu, Re, Ru, Ni, Mn,
An alloy in which one or more elements selected from Ge, Si, O, N, and B are added to CoCr can be used. Ta, Zr, Nb, Cu, Re, Ru, Ni,
A nonmagnetic Co alloy containing Co and one or more elements selected from Mn, Ge, Si, O, N, and B and Co can also be used. If the non-magnetic intermediate film 8 is too thick, the resolution between the non-magnetic intermediate film 5 and the soft magnetic under film 2 is increased due to an increase in the distance, and the noise characteristics are deteriorated. More preferably, the thickness is 10 nm or less. By providing the nonmagnetic intermediate film 8, the orientation of the perpendicular magnetic film 5 can be improved and the coercive force can be increased.

As shown in FIG. 3, in the magnetic recording medium of the present invention, a hard magnetic film 9 made of a hard magnetic material having in-plane magnetic anisotropy is provided between the soft magnetic underlayer 2 and the substrate 1. You can also. The material used for the hard magnetic film 9 is Co
A Cr alloy can be used. A magnetic material (such as a CoSm alloy) made of an alloy of a transition metal and a rare earth element can also be used. The hard magnetic film 9 has a coercive force Hc of 50.
It is preferably 0 (Oe) or more (preferably 1000 (Oe) or more). The thickness of the hard magnetic film 9 is 20 to 15
It is preferably set to 0 nm (preferably 40 to 70 nm). The hard magnetic film 9 is magnetized in a radial direction from the center of the substrate so that the soft magnetic underlayer 2 does not form a domain wall in the substrate radial direction, and exchange coupling is formed between the hard magnetic film 9 and the soft magnetic underlayer 2. Is preferred. Immediately below the hard magnetic film 9,
It is preferable to provide a base film (not shown) made of Cr or a Cr alloy.

By providing the hard magnetic film 9, it is possible to prevent the occurrence of spike noise due to the giant magnetic domains formed by the soft magnetic underlayer 2, and to provide a magnetic recording medium having excellent error rate characteristics and capable of high-density recording. Obtainable. This is for the following reason. The soft magnetic underlayer 2 forms a huge magnetic domain in the in-plane direction of the substrate 1 because the coercive force is small and the direction of magnetization is easily changed. The domain wall, which is the boundary of the magnetic domains in the soft magnetic underlayer 2, may cause spike noise and may lower the error rate of the magnetic recording medium. By providing the hard magnetic film 9 between the soft magnetic under film 2 and the substrate 1, the hard magnetic film 9 and the soft magnetic under film 2
Are exchange-coupled, and the magnetization direction of the soft magnetic underlayer 2 is forcibly directed in the radial direction of the substrate 1 so that the giant magnetic domain is not formed. Therefore, generation of spike noise can be prevented.

FIG. 4 is a sectional view showing an example of a magnetic recording / reproducing apparatus according to the present invention. The magnetic recording / reproducing apparatus shown in FIG. 1 includes a magnetic recording medium 10 having the above configuration, a medium driving unit 11 for driving the magnetic recording medium 10 to rotate, and a magnetic head 1 for recording / reproducing information on / from the magnetic recording medium 10.
2 and a head drive unit 13 for driving the magnetic head 12
And a recording / reproducing signal processing system 14. The recording / reproducing signal system 14 can process input data and send a recording signal to the magnetic head 12, or can process a reproducing signal from the magnetic head 12 and output data.

As the magnetic head 12, a single-pole head can be used. FIG. 5 shows an example of a single-pole head. The single-pole head 12 includes a magnetic pole 15 and a coil 1.
6 and 6. The magnetic pole 15 is formed in a substantially U-shape in side view having a narrow main magnetic pole 17 and a wide auxiliary magnetic pole 18, and the main magnetic pole 17 generates a magnetic field applied to the perpendicular magnetic film 5 during recording, and At the time of reproduction, the magnetic flux from the perpendicular magnetic film 5 can be detected.

When recording is performed on the magnetic recording medium 10 using the single pole head 12, the magnetic flux generated from the tip of the main pole 17 causes the perpendicular magnetic film 5 to move in the direction perpendicular to the substrate 1. Magnetize. At this time, since the magnetic recording medium 10 is provided with the soft magnetic underlayer 2, the magnetic flux from the main magnetic pole 17 passes through the perpendicular magnetic film 5 and the soft magnetic underlayer 2 to form the auxiliary magnetic pole 1.
8 to form a closed magnetic circuit. Since the closed magnetic path is formed between the single-pole head 12 and the magnetic recording medium 10, the efficiency of entering and exiting the magnetic flux increases, and high-density recording / reproduction becomes possible. Although the magnetic flux between the soft magnetic film 2 and the auxiliary magnetic pole 18 is opposite to the magnetic flux between the main magnetic pole 17 and the soft magnetic film 2, the area of the auxiliary magnetic pole 18 is larger than that of the main magnetic pole 17. Since the magnetic flux density is sufficiently large, the magnetic flux density from the auxiliary magnetic pole 18 is sufficiently small, and the magnetic flux from the auxiliary magnetic pole 18 does not affect the magnetization of the perpendicular magnetic film 5. In the present invention, a magnetic head other than a single-pole head, for example, a composite thin-film magnetic recording head having a giant magnetoresistive (GMR) element in a reproducing section can be used.

The magnetic recording medium of the present invention is a magnetic recording medium 1
Since the alloy containing the first and second elements (or the first element alloy containing the above oxides, C and B) is used for the zero orientation control film 4, the crystal orientation of the orientation control film 4 and the perpendicular magnetic film 5 is controlled. Performance can be improved. Further, the crystal grains can be reduced in the orientation control film 4 and the magnetic particles can be reduced in the perpendicular magnetic film 5. Therefore, increase the coercive force,
It is possible to improve the reproduction output and reduce noise. Therefore, high recording density can be achieved.

[0054]

The following examples are provided to clarify the operation and effect of the present invention. (Examples 1 to 36) A cleaned glass substrate 1 (manufactured by OHARA, 2.5 inches in outer diameter) was housed in a film forming chamber of a DC magnetron sputtering apparatus (C-3010, manufactured by Anelva), and the ultimate vacuum degree was set. After the inside of the film forming chamber was evacuated to 1 × 10 ⁻⁵ Pa, 89 at% Co-4 at% Zr-7 at% N was placed on the glass substrate 1 at a temperature of 100 ° C.
A soft magnetic underlayer 2 (thickness: 100 nm) made of b was formed by a sputtering method. Then, at a temperature of 200 ° C.,
On the soft magnetic underlayer 2, 50 at% Ni-50 at% Al
An alignment control base film 3 (thickness: 8 nm) and an alignment control film 4 (thickness: 5 nm) were formed by sputtering. The orientation control film 4 includes a first material (Ru or Re) and a second material.
Raw materials (V, Nb, Ta, Cr, Mo, W, Mn, Ni,
Pd, Pt, Ir, SiO ₂ , ZrO ₂ , HfO ₂ , Ti
An alloy consisting of O ₂ , Al ₂ O ₃ , C or B) was used. The content of the second raw material was as shown in Table 2. Next, 62 at% Co-20 at% Cr-14 at% Pt
A perpendicular magnetic film 5 (thickness: 30 nm) of -4 at% B was formed. In the sputtering step, argon is used as a process gas for film formation, and a gas pressure of 0.5 is used.
Film formation was performed at Pa. Next, a protective film 6 (thickness: 5 nm) made of carbon was formed by a CVD method. Next, a lubricating film 7 (2 nm thick) made of perfluoropolyether was formed by dip coating to obtain a magnetic recording medium.

(Comparative Examples 1 and 2) A magnetic recording medium was manufactured in the same manner as in Example 1 except that the orientation control film was made of Ru or Re.

The magnetic characteristics of each magnetic recording medium were determined by GUZIK
The measurement was performed using a read / write analyzer RWA1632 manufactured by KK and a spin stand S1701MP. For evaluation of magnetic characteristics, a single pole head was used as the magnetic head,
Linear recording density 100 kFCI, error rate 600 kFC
The measurement was performed at I (during regeneration). Table 2 shows the results. H
c indicates a coercive force when the magnetic recording medium is magnetized in a direction perpendicular to the substrate 1.

[0057]

[Table 2]

As shown in Table 2, Ru or Re was used for the orientation control film 4.
In the example using the alloy in which the second raw material was added to Ru or Re for the orientation control film 4, as compared with the comparative example using No., excellent results were obtained in the coercive force Hc, the reproduction output, and the SNR. Understand.

(Example 37) A magnetic recording medium was manufactured in the same manner as in Example 1 except that the distance between the soft magnetic underlayer 2 and the perpendicular magnetic film 5 was changed by changing the thickness of the orientation control underlayer 3. Produced. FIG. 6 shows the results of measurement of overwriting (overwriting, hereinafter referred to as OW) of these magnetic recording media. As shown in FIG.
When the distance between the magnetic layer and the perpendicular magnetic film 5 exceeds 60 nm, O
Whereas W becomes 35 dB or less and the reproduction characteristics are lowered,
It can be seen that excellent reproduction characteristics could be obtained by setting this interval to 60 nm or less.

[0060]

As described above, in the magnetic recording medium of the present invention, the orientation control film includes the first element and the first element.
An alloy containing a second element capable of forming a solid solution with the element,
The structure in which the first element is Ru and / or Re, the second element has a solid solution limit with respect to the first element, and the single crystal thereof does not have the hcp structure, and thus the crystal orientation of the orientation control film is obtained. And the crystal orientation of the perpendicular magnetic film can be improved. Further, the crystal grains can be reduced in the orientation control film and the magnetic particles can be reduced in the perpendicular magnetic film. Therefore, the coercive force can be increased, the reproduction output can be improved, and noise can be reduced.

Further, at least one selected from Si oxide, Zr oxide, Hf oxide, Ti oxide, Al oxide, C and B was added to Ru and / or Re to the orientation control film. By using an alloy, the crystal orientation of the orientation control film and the perpendicular magnetic film can be improved. Further, the crystal grains can be reduced in the orientation control film and the magnetic particles can be reduced in the perpendicular magnetic film. Therefore, while increasing the coercive force and improving the reproduction output,
Noise can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a first embodiment of a magnetic recording medium according to the present invention.

FIG. 2 is a partial sectional view showing a second embodiment of the magnetic recording medium of the present invention.

FIG. 3 is a partial cross-sectional view illustrating a third embodiment of the magnetic recording medium of the present invention.

FIG. 4 is a schematic configuration diagram illustrating an example of a magnetic recording / reproducing apparatus according to the present invention.

5 shows an example of a magnetic head used in the magnetic recording / reproducing apparatus shown in FIG.

FIG. 6 is a graph showing test results.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Non-magnetic substrate, 2 ... Soft magnetic base film, 3 ... Alignment control base film, 4 ... Alignment control film, 5 ... Perpendicular magnetic film, 6 ... Protective film,
10 ... magnetic recording medium, 12 ... magnetic head

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akira Sakawaki 5-1, Yawata Kaigandori, Ichihara-shi, Chiba Prefecture Inside Showa Denko H.D. Co., Ltd. (1) Inside Showa Denko H.D. Co., Ltd. (72) Inventor Masato Kokubu 5-1, Yawata Kaigan-dori, Ichihara City, Chiba Prefecture Inside Showa Denko H. D. Co., Ltd. (72) Inventor Hiroshi Sakai Ichihara, Chiba Prefecture 5th, Yawata Kaigandori Showa Denko H.D. Co., Ltd. F-term (reference) 5D006 CA01 CA06 DA08 EA03 5D112 AA03 BD03 BD08

Claims (8)

[Claims] 1. A non-magnetic substrate, comprising: a soft magnetic underlayer made of at least a soft magnetic material; an orientation control underlayer; an orientation control film for controlling the orientation of a film immediately above the nonmagnetic substrate; A perpendicular magnetic film mainly oriented vertically and a protective film are provided, and the orientation control film is made of an alloy containing a first element and a second element which is soluble in the first element. A magnetic recording medium, wherein the element is Ru and / or Re, the second element has a solid solution limit with respect to the first element, and a single crystal thereof does not have an hcp structure. 2. The method according to claim 1, wherein the second element is V, Nb, Ta, Cr,
2. The material according to claim 1, wherein the material is at least one selected from Mo, W, Mn, Ni, Pd, Pt, and Ir.
The magnetic recording medium according to the above. 3. A soft magnetic underlayer made of at least a soft magnetic material on a nonmagnetic substrate, an orientation control underlayer, an orientation control film for controlling the orientation of a film immediately above, and an easy axis of magnetization with respect to the substrate. A perpendicular magnetic film mainly oriented vertically and a protective film are provided. The orientation control film is made of Si oxide, Zr oxide, Hf oxide,
A magnetic recording medium comprising an alloy obtained by adding at least one selected from Ti oxide, Al oxide, C, and B to Ru and / or Re. 4. The alignment control underlayer is made of NiAl or FeA.
1, CoFe, CoZr, NiTi, AlCo, AlR
The magnetic recording medium according to any one of claims 1 to 3, wherein one or more alloys of u and CoTi are used as main components. 5. The magnetic recording medium according to claim 1, wherein an interval between the soft magnetic underlayer and the perpendicular magnetic layer is 60 nm or less. 6. A non-magnetic substrate, comprising: a soft magnetic under film made of at least a soft magnetic material; an orientation control under film; an orientation control film for controlling the orientation of the film immediately above; What is claimed is: 1. A method for manufacturing a magnetic recording medium comprising a perpendicular magnetic film mainly oriented vertically and a protective film, wherein the orientation control film comprises a first element and a second element capable of forming a solid solution with the first element. Wherein the first element is Ru and / or Re, the second element has a solid solution limit to the first element, and the single crystal thereof does not have an hcp structure. A method for manufacturing a magnetic recording medium. 7. A non-magnetic substrate, comprising: a soft magnetic underlayer made of at least a soft magnetic material; an orientation control underlayer; an orientation control film for controlling the orientation of the film immediately above; What is claimed is: 1. A method for manufacturing a magnetic recording medium comprising a perpendicular magnetic film mainly oriented vertically and a protective film, wherein the orientation control film is formed of a Si oxide, a Zr oxide, a Hf oxide,
A method for manufacturing a magnetic recording medium, comprising an alloy in which at least one selected from Ti oxide, Al oxide, C, and B is added to Ru and / or Re. 8. A magnetic recording / reproducing apparatus comprising: the magnetic recording medium according to claim 1; and a magnetic head for recording / reproducing information on / from the magnetic recording medium.