JP2911783B2 - Magnetic recording medium and method of manufacturing the same - Google Patents

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 such as a magnetic disk and a magnetic tape and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, a magnetic recording medium having a magnetic layer formed of a metal magnetic thin film manufactured by sputtering or vacuum evaporation has attracted attention. As is well known, a major reason why a metal magnetic thin film has attracted attention as a magnetic recording medium is that a higher recording density can be realized as compared with a conventional magnetic recording medium coated with magnetic powder. As a magnetic material for such a metal magnetic thin film, a Co-containing alloy is known to exhibit good coercive force and squareness. Particularly in recent years, CoPt-based alloy thin films have
Due to its high coercive force and high residual magnetic flux density, it has attracted a great deal of industrial attention as a material that can cope with high density magnetic recording.

Further, in a magnetic recording medium for an MR (magnetoresistive) head, it is required that the medium noise is smaller than the magnitude of the output. To meet such demands, there is known a magnetic recording medium in which two magnetic layers of CoPtCr are provided on a substrate, and a non-magnetic intermediate layer made of Cr is interposed between the two magnetic layers. [JP 2
-210614 gazette]. In this magnetic recording medium, since the magnetic layer is divided into two layers by a non-magnetic intermediate layer, the thickness of each magnetic layer is smaller than that of a single magnetic layer having the same total thickness. Can be reduced at the time of reproduction.

[0004]

However, as a result of various studies on characteristics other than the medium noise of the magnetic recording medium described in the above publication from a practical viewpoint, the following problems were found. The coercive force is remarkably reduced as compared with the case of only one magnetic layer. Overwriting characteristics (overwrite characteristics) are insufficient.

Accordingly, a first object of the present invention is to provide a magnetic recording medium having two or more CoPt-based alloy magnetic layers divided by a non-magnetic intermediate layer, which has low medium noise, coercive force and overwrite. An object of the present invention is to provide a magnetic recording medium having excellent characteristics and a method for manufacturing the same.

Incidentally, CoNiCr alloys and CoCrT
It is known that a high coercive force can be obtained by using Cr as a base layer in a magnetic recording medium having a magnetic layer such as an a alloy (for example, IEEE TRANSACTION ON MAGNETIC).
S VOL.MAG-3, NO.3 (1967) p205-207).

However, in the case of a CoPt alloy magnetic layer, there is a problem that the use of an underlayer consisting of a single component of Cr deteriorates the C-axis orientation. Since the atomic radius of Pt is large, the lattice constant of the CoPt-based alloy magnetic layer is larger than the crystal lattice constant of a conventional magnetic layer such as a CoNiCr alloy or a CoCrTa alloy. For this reason, the consistency of the atomic arrangement with the underlayer consisting of a single component of Cr was deteriorated, and as a result, the C-axis orientation was also poor. As a means for solving this problem, it has been proposed to add a second metal (a dissimilar metal) for increasing the crystal lattice constant to the Cr underlayer. Cr
By changing the lattice constant of the alloy underlayer using a Cr alloy (for example, CrV) underlayer to which a dissimilar metal is added, the C-axis orientation of the magnetic layer in the film plane is improved, and the coercive force and the squareness ratio are improved. Can be improved.
No. 6848).

However, as a result of the study by the present inventors,
It has been clarified that the medium noise increases sharply by adding a dissimilar metal to the Cr underlayer.

Accordingly, a second object of the present invention is to provide two or more CoPt layers divided by a Cr alloy underlayer and a non-magnetic intermediate layer.
An object of the present invention is to provide a magnetic recording medium having a system alloy magnetic layer, which has low medium noise and a method of manufacturing the same. In addition, a third object of the present invention is a magnetic recording medium having a Cr alloy underlayer and a CoPt-based alloy magnetic layer, the magnetic recording medium having high coercive force and squareness ratio and low medium noise, and a method of manufacturing the same. Is to provide. Further, a fourth object of the present invention is a magnetic recording medium having two or more CoPt-based alloy magnetic layers divided by a Cr alloy underlayer and a nonmagnetic intermediate layer, which has low medium noise, coercive force and An object of the present invention is to provide a magnetic recording medium having excellent overwriting characteristics and a method for manufacturing the same.

The present inventors have conducted various studies. As a result, in a magnetic recording medium having two or more CoPt-based alloy magnetic layers divided by a non-magnetic intermediate layer, the magnetic coercive force and the overwriting characteristics are deteriorated. It was found that the composition of the film material for dividing the layers and the production conditions were satisfied. When a CoPt-based alloy is used as the magnetic layer, an alloy mainly composed of Cr and Mo is used for the non-magnetic intermediate layer that divides the magnetic layer, and the crystal of the (002) plane of the CoPt-based alloy magnetic layer is used. The lattice spacing and (11) of the Cr alloy non-magnetic underlayer immediately below the magnetic layer
It has been found that by matching the difference in the crystal lattice spacing between the 0) planes, the medium noise can be further reduced without lowering the coercive force and the overwriting characteristics.

As a result of studies by the present inventors, it has been found that the addition of a dissimilar metal (for example, Mo) to the Cr underlayer causes non-uniformity in crystal grain size and reduction in crystallinity. Observation revealed. That is, a CoPt-based alloy magnetic layer (for example, C
oPtCr or the like grows strongly affected by the grain size and crystallinity of the underlayer. Therefore, it has been found that if the crystal grain size of the Cr alloy underlayer is non-uniform and the crystallinity is poor, the magnetic layer has non-uniform crystal grain size and the crystallinity is significantly reduced. It has been found that this causes an increase in medium noise.

Then, when a second underlayer of a Cr alloy in which a different kind of metal was added to Cr was laminated on a film (underlayer) having a uniform crystal grain size and good crystallinity, it was found that the crystal of the Cr alloy underlayer was It was experimentally found that the particle size became uniform and the crystallinity improved. However, reduction of the medium noise is not sufficient only by using two underlayers.

[0013] Then, further investigation revealed that CoPt
Matching the crystal lattice spacing of the (002) plane of the base alloy magnetic layer with the crystal lattice spacing of the (110) plane of the Cr alloy (Cr added with a dissimilar metal) which is the uppermost layer of the underlayer. It was found that the medium noise was significantly reduced. That is, by reducing the difference between the crystal lattice spacing of the (002) plane of the CoPt-based alloy magnetic layer and the crystal lattice spacing of the (110) plane of the Cr alloy underlayer, which is the uppermost layer of the underlayer, the coercive force is reduced. And the squareness ratio can be improved, and at the same time, the medium noise can be reduced.

It is desirable that the difference between the crystal lattice spacing of the (002) plane of the CoPt-based alloy magnetic layer and the crystal lattice spacing of the (110) plane of the Cr alloy underlayer or the Cr alloy intermediate layer be zero. Do not mean. From the results of various experiments, it is preferable to have a slight difference from the viewpoint of noise reduction. That is, the medium noise is reduced by controlling the C-axis orientation of the magnetic layer within a certain range.

[0015]

Accordingly, the present invention provides a magnetic recording medium having a non-magnetic underlayer and a CoPt-based magnetic layer group on a substrate in this order, wherein the CoPt-based magnetic layer group comprises:
It is composed of two or more magnetic layers, with Cr and Mo between each magnetic layer.
And a non-magnetic intermediate layer made of a material mainly composed of Cr and Mo immediately below the magnetic layer based on the crystal lattice spacing of the hcp (002) plane of the magnetic layer. The difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the bcc (110) plane of the magnetic intermediate layer is 0.002 to 0.
The present invention relates to a magnetic recording medium (the magnetic recording medium of the first embodiment), which is in a range of 032 Å.

Further, the present invention relates to a magnetic recording medium having a non-magnetic underlayer and a CoPt-based magnetic layer group in this order on a substrate, wherein the CoPt-based magnetic layer group comprises two or more magnetic layers. A non-magnetic intermediate layer made of a material containing Cr and Mo as main components between the magnetic layers;
The difference (d) is obtained by subtracting the crystal lattice spacing of the bcc (110) plane of the nonmagnetic intermediate layer made of a material mainly composed of Cr and Mo directly below the magnetic layer from the crystal lattice spacing of the (002) plane.
₍₀₀₂₎ -d ₍₁₁₀₎ ) is in the range of 0.002 to 0.032 angstroms, and the nonmagnetic underlayer is composed of one or more layers, and is the lowermost layer of the CoPt-based magnetic layer group. The nonmagnetic underlayer immediately below the magnetic layer is made of a material containing Cr and Mo as main components, and the Cr and Mo are determined from the crystal lattice spacing of the hcp (002) plane of the lowermost magnetic layer in the magnetic layer group. Bcc of the nonmagnetic underlayer made of a material mainly composed of
Difference (d ₍₀₀₂₎ −
d ₍₁₁₀₎ ) in the range of 0.002 to 0.032 angstroms (the magnetic recording medium of the second embodiment).

Further, the present invention provides the method for manufacturing a magnetic recording medium according to the first aspect of the present invention, wherein the CoPt-based magnetic layer group and the non-magnetic intermediate layer made of a material containing Cr and Mo as main components are provided. The substrate heating temperature range is 250 ° C. to 425 ° C.,
The present invention relates to a method for manufacturing a magnetic recording medium, wherein the magnetic recording medium is formed by a sputtering method with an Ar gas pressure range of 0.5 to 10 mTorr.

In addition, the present invention provides the method for manufacturing a magnetic recording medium according to the second aspect of the present invention, wherein the non-magnetic underlayer made of a material containing at least Cr and Mo as main components;
The t-type magnetic layer group and the non-magnetic intermediate layer made of a material containing Cr and Mo as main components were heated at a substrate heating temperature range of 250 ° C. to 42 ° C.
5 ° C., Ar gas pressure range 0.5 to 10 mTorr
The present invention relates to a method for manufacturing a magnetic recording medium, which is formed by a sputtering method. Hereinafter, the present invention will be described.

The magnetic recording medium of the present invention has a CoPt-based magnetic layer group, the magnetic layer group includes two or more magnetic layers, and has a non-magnetic intermediate layer between each magnetic layer. At least one of the nonmagnetic intermediate layers is a nonmagnetic intermediate layer made of a material containing Cr and Mo as main components. Each magnetic layer is made of CoP
It is a t-based alloy, that is, an alloy containing Co and Pt as main components. From the viewpoint of obtaining a sufficient coercive force, the alloy containing Co and Pt as main components is suitably an alloy having a total of 70 at% or more of Co and Pt. Although there is no particular limitation on the ratio of Co to Pt, considering the coercive force, noise and cost, Pt (at%) / Co (at%) is 0.1%.
Suitably, it is in the range of 07 or more and 0.2 or less.

There are no particular restrictions on the components other than Co and Pt, but for example, Cr, Ta, Ni, Si, B, O, N,
One or more of Nb, Mn, Mo, Zn, W, Pb, Re, V, Sm and Zr can be used as appropriate. The addition amount of these elements is appropriately determined in consideration of the magnetic characteristics and the like, and is usually preferably 30 at% or less. More specific materials for the magnetic layer include, for example, CoP
tCr alloy, CoPtTa alloy, CoPtCrB alloy,
CoPtCrTa alloy, CoPtCrNi alloy and the like can be mentioned.

Further, at least one non-magnetic intermediate layer includes:
It is made of a material containing Cr and Mo as main components. This Cr and M
A non-magnetic intermediate layer made of a material mainly containing o
It is called a CrMo-based nonmagnetic intermediate layer. When the CrMo-based nonmagnetic intermediate layer is composed of only Cr and Mo, the amount of Mo added to the Cr metal is set to 40 atomic% or less, so that a film having a uniform crystal grain system and good crystallinity can be obtained. It is appropriate from the viewpoint.

Further, instead of part of Mo, Zr, W,
B, V, Nb, Ta, Fe, Ni, Re, Ce, Zn,
One or more of P, Si, Ga, Hf, Al, Ti and the like can be added. It is appropriate that the total amount of these components and the amount of Mo be 40 atom% or less from the viewpoint that a film having a uniform crystal grain system and good crystallinity can be obtained. However, the amount of Mo or the like added to Cr can be appropriately adjusted depending on the content of Co, Pt or other additional elements in the magnetic layer and the type of the additional element.

For example, in the CoPtCr alloy magnetic layer, the Pt content is set to 4 to 20 at%, the Cr content is set to 3 to 30 at%, and the CrMo-based non-magnetic intermediate layer immediately thereunder is formed of CrM.
In the case of o, the content of Mo in the CrMo-based non-magnetic intermediate layer is set to 2 to 20 atomic%,
The non-magnetic intermediate layer has a uniform crystal grain size and good crystallinity,
Further, the difference between the crystal lattice constants of the CrMo-based non-magnetic intermediate layer and the magnetic layer is easily controlled within an appropriate range, which is preferable. Further, the Mo content is particularly preferably 5 to 10 atomic% because Hc is large and has a high S / N ratio.

CrMoZ as a CrMo-based non-magnetic intermediate layer
When an r alloy is used, it is preferable that a high Hc, Mrδ, and an S / N ratio are obtained. When Zr is added to the CrMo alloy, the noise reduction effect is further enhanced, so that S / N
This is because the ratio is improved. In order to bring out such an effect, the content of Zr is preferably set in a range of 2 to 5 at%.

The number of magnetic layers constituting the magnetic layer group may be two or more, three layers, four layers or more in consideration of reproduction output and overwriting characteristics.
, Five layers or the like. However, from a practical viewpoint, the number of layers is usually about 5 at the maximum. However, if necessary, six or more magnetic layers can be provided.

The magnetic recording medium of the present invention has a non-magnetic intermediate layer in at least one of two or more magnetic layers, and at least one of the non-magnetic intermediate layers is a CrMo-based non-magnetic intermediate layer. . The non-magnetic intermediate layer is provided directly between the magnetic layers, and if necessary, another layer may be provided between the magnetic layer and the non-magnetic intermediate layer thereabove. Also,
When there are three or more magnetic layers, it is preferable to provide a non-magnetic intermediate layer between each magnetic layer. In this case, if the number of magnetic layers is n, n-1 nonmagnetic intermediate layers are provided. However, when there are three or more magnetic layers, in some cases, a non-magnetic intermediate layer is not provided between all the magnetic layers,
A non-magnetic intermediate layer can be provided at least between the magnetic layers.

The layer structure of the magnetic layer group includes, for example, a magnetic layer—a nonmagnetic intermediate layer—a magnetic layer, a magnetic layer—a nonmagnetic intermediate layer—a magnetic layer—a nonmagnetic intermediate layer—a magnetic layer, Non-magnetic intermediate layer-magnetic layer-non-magnetic intermediate layer-magnetic layer-non-magnetic intermediate layer-magnetic layer. Further, the number of sets of the magnetic layer and the non-magnetic intermediate layer can be appropriately increased. In addition, the material and the thickness of each magnetic layer may be the same or different. Similarly, when there are two or more non-magnetic intermediate layers, the materials and thicknesses of the respective non-magnetic intermediate layers may be the same or different.

It is appropriate that the thickness of each magnetic layer is 20 to 230 °, preferably 40 to 150 °. If it is less than 20 °, a sufficient coercive force cannot be obtained, and if it exceeds 230 °, the overwriting characteristics tend to deteriorate and the medium noise tends to increase. The thickness of each non-magnetic intermediate layer is suitably 10 to 100 °, preferably 30 to 80 °. If it is less than 10 °, a sufficient coercive force cannot be obtained, and if it exceeds 100 °, the output tends to decrease, the overwriting characteristics deteriorate, and the medium noise tends to increase.

In the magnetic recording medium of the present invention, the bcc (11) of the CrMo-based nonmagnetic intermediate layer immediately below the magnetic layer is determined from the crystal lattice spacing of the hcp (002) plane of the magnetic layer.
Difference obtained by subtracting the crystal lattice spacing of the (0) plane (d ₍₀₀₂₎ −d
₍₁₁₀₎ ) is suitably in the range of 0.002 to 0.032 angstroms. The above (d ₍₀₀₂₎ -d
₍₁₁₀₎ ) is less than 0.002 angstroms and 0.1.
When it exceeds 032 Å, Hc decreases and the S / N ratio also decreases. When two or more CrMo-based nonmagnetic intermediate layers are provided, the above (d ₍₀₀₂₎ −
d ₍₁₁₀₎ ) is independently 0.0 for each non-magnetic intermediate layer.
02 to 0.032 angstroms.

From the viewpoint of obtaining a higher S / N ratio, the crystal lattice spacing of the bcc (110) plane of the CrMo-based nonmagnetic intermediate layer is subtracted from the crystal lattice spacing of the hcp (002) plane of the magnetic layer. The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) is 0.0
Preferably, it is in the range of 14 to 0.030 angstroms. When there are two or more CrMo-based non-magnetic intermediate layers, the above (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) may be independently in the range of 0.014 to 0.030 angstroms for each non-magnetic intermediate layer. preferable.

Further, the magnetic recording medium of the present invention has one or more nonmagnetic underlayers, and the nonmagnetic underlayer in contact with the lowermost layer of the CoPt-based magnetic layer group contains Cr and Mo as main components. It consists of the material which does. This non-magnetic underlayer is hereinafter referred to as Cr
It is referred to as a Mo-based nonmagnetic underlayer. When the CrMo-based nonmagnetic underlayer is composed of only Cr and Mo, the amount of Mo added to the Cr metal is set to 40 atomic% or less, whereby a film having a uniform crystal grain system and good crystallinity can be obtained. It is appropriate from the viewpoint.

Further, instead of part of Mo, Zr, W,
B, V, Nb, Ta, Fe, Ni, Re, Ce, Zn,
One or more of P, Si, Ga, Hf, Al, Ti and the like can be added. It is appropriate that the total amount of these components and the amount of Mo be 40 atom% or less from the viewpoint that a film having a uniform crystal grain system and good crystallinity can be obtained. However, the amount of Mo or the like added to Cr can be appropriately adjusted depending on the contents of Co, Pt or other additional elements in the magnetic layer in contact with the CrMo-based nonmagnetic underlayer, and the types of the additional elements.

For example, in the CoPtCr alloy magnetic layer, the Pt content is set to 4 to 20 at%, the Cr content is set to 3 to 30 at%, and the CrMo-based non-magnetic underlayer immediately below the CrMo based non-magnetic underlayer is made of CrM.
In the case of o, the content of Mo in the CrMo-based nonmagnetic underlayer is preferably set to 2 to 20 atomic%,
The non-magnetic underlayer has a uniform crystal grain size and good crystallinity,
Further, the difference between the crystal lattice constants of the CrMo-based nonmagnetic underlayer and the magnetic layer can be easily controlled within an appropriate range, which is preferable. Further, the Mo content is particularly preferably 5 to 10 atomic% because Hc is large and has a high S / N ratio.

The thickness of the CrMo-based nonmagnetic underlayer is 10 to
Suitably, it is 150 °. The upper and lower limits of the thickness of the CrMo-based non-magnetic underlayer are determined so that the film has a uniform crystal grain size and good crystallinity, and has a crystal lattice spacing suitable for the magnetic layer. From such a viewpoint, C
The preferred thickness of the rMo-based nonmagnetic underlayer is 20 to 100.
Å.

As a CrMo-based nonmagnetic underlayer, CrMoZ
When an r alloy is used, it is preferable that high Hc, Mr δ, and S / N ratio be obtained. This is because when Zr is added to the CrMo alloy, the noise reduction effect is further enhanced, and the S / N ratio is improved. In order to bring out such an effect, the content of Zr is preferably set in a range of 2 to 5 at%. This characteristic also depends on the film thickness.
The film thickness of the MoZr alloy nonmagnetic underlayer is 10 to 150 °, particularly preferably 20 to 100 °. If it is less than 10 °, sufficient Hc may not be obtained, and if it exceeds 150 °, the output tends to decrease, the overwriting characteristics deteriorate, and noise tends to increase.

In the magnetic recording medium of the present invention, the Cp is determined from the crystal lattice spacing of the hcp (002) plane of the magnetic layer.
The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the bcc (110) plane of the rMo-based nonmagnetic underlayer is 0.00
It is in the range of 2 to 0.032 angstroms. (D
_{If (002)} −d ₍₁₁₀₎ ) is less than 0.002 Å or more than 0.032 Å, Hc decreases and the S / N ratio also decreases. In order to obtain a higher S / N ratio, it is preferable that (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) be in the range of 0.014 Å to 0.030 Å.

In the magnetic recording medium of the present invention, the C
One more layer or two between the rMo-based nonmagnetic underlayer and the substrate
It can have more than one non-magnetic underlayer. And
The nonmagnetic underlayer in contact with the CrMo-based nonmagnetic underlayer is preferably made of a metal having a body-centered cubic crystal structure.
An example of the nonmagnetic underlayer made of a metal having a body-centered cubic crystal structure is a Cr underlayer. The CrM
The nonmagnetic underlayer in contact with the o-based nonmagnetic underlayer is preferably a metal film having a uniform crystal grain size and good crystallinity,
It was experimentally confirmed that the Cr film was most preferable. In addition, as a metal having a body-centered cubic crystal structure,
i, Ta, and Zr can be exemplified.

The thickness of the nonmagnetic underlayer made of a metal having a body-centered cubic crystal structure is suitably in the range of 100 to 1000 °. The upper and lower limits of this nonmagnetic underlayer are:
The thickness of the non-magnetic underlayer is in the range of 100 to 800 ° in order to determine a film having a uniform crystal grain size and good crystallinity, and particularly to have a large Hc and a high S / N ratio. It is appropriate to do so. Further, the ratio of (film thickness of CrMo-based nonmagnetic underlayer) / (film thickness of nonmagnetic underlayer made of metal having a body-centered cubic crystal structure) is 0.05 to 0.5.
It is preferable from the viewpoint that Hc is large and the S / N ratio is high.

In the magnetic recording medium of the present invention, another nonmagnetic underlayer can be further provided between the nonmagnetic underlayer made of the metal having the body-centered cubic crystal structure and the nonmagnetic substrate. As such a nonmagnetic underlayer, Al, T
i, Zr film and the like. The thickness of this nonmagnetic underlayer can be, for example, 10 to 100 °. The upper limit and the lower limit of the thickness of the nonmagnetic underlayer are determined as ranges in which a film made of a metal having a body-centered cubic crystal structure laminated thereon has a uniform crystal grain size and good crystallinity. In order to further increase Hc and have a high S / N ratio, the film thickness is preferably 30 to 80 °.

In the magnetic recording medium of the present invention, a protective layer and a lubricating layer can be provided on the CoPt-based magnetic layer.
The protective layer has a role of protecting the magnetic layer from chemical attack such as moisture, and a protective layer on the magnetic layer (the surface opposite to the non-magnetic substrate) for the purpose of protecting the magnetic layer from damage caused by sliding contact with the head. There is a protective layer provided to provide abrasion resistance. The protective layer can be composed of one or more layers of different materials. In the magnetic recording medium of the present invention, the material and structure of the protective layer are not particularly limited. Examples of the material include a metal film such as Cr as a chemical protection layer, and a silicon oxide film, a carbon film, a zirconia film, a hydrogenated carbon film, a nitrogen film as a protection layer for imparting wear resistance. Examples include a silicon film and a SiC film.

The lubricating layer is a film provided for the purpose of resisting sliding by contact with the head, and the material and the like are not particularly limited. For example, perfluoropolyether and the like can be mentioned.

The material of the substrate is not particularly limited as long as it is a non-magnetic substrate. For example, a glass substrate, a crystallized glass substrate, an aluminum substrate, a ceramic substrate, a carbon substrate, a silicon substrate, or the like can be used.

The magnetic recording medium according to the first embodiment of the present invention can be manufactured by using a known thin film forming method such as a sputtering method. In particular, while adjusting the composition of the CrMo-based non-magnetic intermediate layer,
By adjusting the conditions for forming the Pt-based magnetic layer, it is possible to obtain a magnetic recording medium having a difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) of the crystal lattice spacing in a predetermined range.

Further, the magnetic recording medium according to the second embodiment of the present invention can be manufactured by using a known thin film forming method such as a sputtering method. In particular, by adjusting each composition of the CrMo-based non-magnetic underlayer and the CrMo-based non-magnetic intermediate layer, and by adjusting the formation conditions of the CrMo-based non-magnetic under-layer, CrMo-based non-magnetic intermediate layer, and CoPt-based magnetic layer, The difference in the crystal lattice plane spacing in a predetermined range (d ₍₀₀₂₎ −d
₍₁₁₀₎ ) can be obtained.

For example, at least the CrMo-based non-magnetic underlayer and / or the CrMo-based non-magnetic intermediate layer and the CoPt-based magnetic layer are heated at a substrate heating temperature range of 250 ° C. to 425 ° C.
A magnetic recording medium having a predetermined range of crystal lattice spacing difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) can be obtained by forming the Ar gas pressure range from 0.5 to 10 mTorr by a sputtering method. it can. The range of the substrate heating temperature is preferably from 300C to 400C. Also, Ar
The range of the gas pressure is preferably 1 to 8 mTorr.

Since the magnetic recording medium of the present invention has low medium noise, it is useful for magnetic disks, magnetic tapes and the like. Furthermore, the magnetic recording medium of the present invention has reduced medium noise, high coercive force and squareness, and excellent overwriting characteristics depending on the configuration. Further, the magnetic recording medium of the present invention is useful as a magnetic recording medium for an MR (magnetoresistive) head because the medium noise is small.

[0047]

The present invention will be described in detail below with reference to examples and comparative examples.

Embodiment 1 As shown in FIG. 1, the magnetic recording medium of this embodiment has a base layer 2, a first magnetic layer 3, a non-magnetic intermediate layer 4,
This is a magnetic disk in which a magnetic layer 5, a protective layer 6, and a lubricating layer 7 are sequentially laminated.

The glass substrate 1 is made of aluminosilicate glass, and its surface is mirror-polished to Ra = about 50 °. The underlayer 2 is made of an Al thin film 2a from the glass substrate 1 side.
(Thickness 50 mm), Cr thin film 2b (thick 600 mm), Cr
It is composed of the Mo thin film 2c (50 ° in thickness). The CrMo thin film 2c has a composition ratio of 98 atomic% of Cr and 2 atomic% of Mo.

The first magnetic layer 3 and the second magnetic layer 5 are made of the same material CoPtCr alloy (Co: 78 atomic%, Pt: 11 atomic%, Cr: 11 atomic%), and each has a thickness of 1%.
20 °. The non-magnetic intermediate layer 4 existing between the first magnetic layer 3 and the second magnetic layer 5 is made of a 50 .mu.m thick CrMo alloy (Cr: 98 atomic%, Mo: 2 atomic%).

The protective layer 6 comprises a first protective layer 6a and a second protective layer 6b from the substrate side. The first protective layer 6a has a thickness of 50
The Cr film is a chemical protection film for the magnetic layer. The other second protective layer 6b is made of a silicon oxide film having a thickness of 160 ° in which hard fine particles are dispersed, and the second protective layer 6b provides wear resistance. Lubrication layer 7
Is made of perfluoropolyether, and this film alleviates the contact with the magnetic head.

Hereinafter, a method for manufacturing the magnetic disk will be described. The above glass substrate is used as a substrate holder (pallet)
After the pallet 18 is introduced into the charging chamber 11 of the in-line type sputtering apparatus 10 shown in FIG.
Is evacuated from the atmospheric state until the degree of vacuum in the sputtering chamber (vacuum chamber) 12 becomes equal to that of the vacuum chamber. Then, the partition plate 1
4 and the pallet 18 is moved to the first vacuum chamber 12a.
Introduce within. In the first vacuum chamber 12a,
The glass substrate mounted on the pallet 18 is
After heating at 300 ° C. for 1 minute by heating, the pallet 18 was moved at a transport speed of 1.2 m / min.
In a discharge state under the condition of an Ar gas pressure of 5 mTorr,
The target is sequentially passed between the targets 15a and 16a and the targets 15b and 16b which are arranged to face each other. The targets are arranged in the order of Al and Cr with respect to the pallet transport direction, and the Al underlayer 2a and the Cr underlayer 2b are laminated on both surfaces of the glass substrate in the order of the arranged targets. The input power of the Al target is 30
Sputtering was performed at a power of 1.0 kW with a 0 W, Cr target.

Next, the pallet 18 is moved to the second vacuum chamber 12b through the port 21, and the substrate is heated again by the heater 20 arranged in the second vacuum chamber 12b. The heating condition is 375 ° C. for 1 minute. afterwards,
CrMo targets 15c and 16c, CoPtCr targets 15d and 16d, CrMo targets 15e and 1
6e, CoPtCr targets 15f and 16f, Cr targets 15g and 16g are arranged in this order, and 1.2 m / g is set between targets 15c-16c to 15g-16g in a discharge state under the condition of Ar gas pressure of 1.3 mTorr.
The pallets 18 are sequentially passed at a transport speed of min. Then, in the order of the arranged targets, the CrMo
Each layer is laminated in the order of the underlayer 2c, the CoPtCr first magnetic layer 3, the CrMo non-magnetic intermediate layer 4, the CoPtCr second magnetic layer 5, and the Cr first protective layer 6a. The input power of the CrMo target was 500 W, the input power of the CoPtCr target was 300 W, and the input power of the Cr target was 50 W.
Sputtering was performed at 0W. Furthermore, the ultimate pressure (degree of vacuum) in the first vacuum chamber and the second vacuum chamber is 5 ×
10 ^-6 Torr or less.

After completion of the film formation by the above-mentioned sputtering, the first protective layer 6a is subjected to a hydrophilization treatment by IPA (isopropyl alcohol) cleaning, and then the substrate is treated with an organic silicon compound solution in which silica fine particles (particle diameter: 100 °) are dispersed. (Water and IP
A mixed solution of A and tetraethoxysilane) and baked to form a second protective layer 6b made of SiO ₂ . Finally, a lubricant made of perfluoropolyether is dipped on the second protective layer 6b to form a lubricating layer 7
Was formed.

The running test of the magnetic disk thus obtained was performed at a head flying height of 0.075 μm or less. As a result, it was good. Then, the coercive force (Hc), the product of the residual magnetization film thickness (Mrδ), and the S / N ratio were evaluated. Table 1 shows the results. Further, the composition and thickness of the CrMo underlayer 2c, the composition and thickness of the CrMo non-magnetic intermediate layer 4,
The substrate heating temperature and the Ar gas pressure when the underlayer 2c and the CrMo nonmagnetic intermediate layer 4 were formed, and the (0) of the CoPtCr magnetic layer 3
The difference (d) obtained by subtracting the crystal lattice spacing of the (110) plane of the CrMo underlayer 2c in contact therewith from the crystal lattice spacing of the (02) plane.
₍₀₀₂₎ −d ₍₁₁₀₎ ) and the crystal lattice spacing of the (002) plane of the CoPtCr magnetic layer 5 and the CrM in contact therewith.
Table 1 shows the difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the (110) plane of the nonmagnetic intermediate layer 4.

The CrMo underlayer 2c in contact with the (002) crystal lattice spacing of the CoPtCr magnetic layer 3
Difference (d ₍₀₀₂₎ −
d ₍₁₁₀₎ ) and the difference (d ₍₀₀₂₎₎ obtained by subtracting the crystal lattice spacing of the (110) plane of the CrMo nonmagnetic intermediate layer 4 in contact with the crystal lattice spacing of the (002) plane of the CoPtCr magnetic layer 5.
−d ₍₁₁₀₎ ) is the same because the manufacturing conditions of the underlayer 2c and the non-magnetic intermediate layer 4 and the manufacturing conditions of the magnetic layer 3 and the magnetic layer 5 were the same. ,
Together, only one value is shown. Table 2 is similar.

The S / N was evaluated as follows.
Using a thin film head having a magnetic head flying height of 0.060 μm, the relative speed between the thin film head and the disk was set to 5.0 m /
The recording / reproducing output at a linear recording density of 110 kfci was measured. In addition, carrier frequency 13.5 MHz
Then, the noise spectrum at the time of signal recording and reproduction was measured for this magnetic disk by a spectrum analyzer with the measurement band set to 27 MHz. The MR (magnetoresistive) head used in the above measurement has a recording track width of 4.2 μm, a reproduction track width of 3.5 μm, a recording gap length of 0.43 μm, and a reproduction gap length of 0.31 μm.

Examples 2 to 29 In Examples 2 to 25, the composition and thickness of the CrMo-based underlayer 2c, the composition and thickness of the CrMo nonmagnetic intermediate layer 4,
A magnetic disk was manufactured in the same manner as in Example 1 except that the substrate heating temperature and the Ar gas pressure at the time of manufacturing the o-based underlayer 2c and the CrMo nonmagnetic intermediate layer 4 were changed as shown in Table 1. In Examples 26 to 29, the CrMo-based underlayer 2
c and CrMo nonmagnetic intermediate layer 4 is formed of
Example 1 except that a Zr alloy was used and the composition ratio was as shown in Table 2.
A magnetic disk was produced in the same manner as described above.

A running test of the magnetic disk thus obtained was performed at a head flying height of 0.075 μm or less. As a result, it was good. Then, the coercive force (Hc), the product of the residual magnetization film thickness (Mrδ), and the S / N ratio were evaluated. Note that S
The measurement of the / N ratio was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2. Further, the composition and thickness of the CrMo underlayer 2c, the composition and thickness of the CrMo non-magnetic intermediate layer 4,
Substrate heating temperature and Ar gas pressure during preparation of rMo underlayer 2c and CrMo nonmagnetic intermediate layer 4, CoPtCr magnetic layer 3
Of the (002) plane of the crystal lattice
The difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the (110) plane of the Mo underlayer 2c, and the C lattice contacting the crystal lattice plane spacing of the (002) plane of the CoPtCr magnetic layer 5,
Tables 1 and 2 show the difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the (110) plane of the rMo nonmagnetic intermediate layer 4.

Comparative Examples 1 to 6 In Comparative Example 1, a magnetic disk was manufactured in the same manner as in Example 1 except that the underlayer 2c and the nonmagnetic intermediate layer 4 were changed to Cr. In Comparative Example 2, a magnetic disk was manufactured in the same manner as in Example 1 except for the composition ratio of the CrMo base layer 2c and the CrMo nonmagnetic intermediate layer 4. In Comparative Examples 3 and 4, magnetic disks were manufactured in the same manner as in Example 1 except that the substrate heating temperature and the Ar gas pressure during the formation of the CrMo-based underlayer 2c and the CrMo nonmagnetic intermediate layer 4 were changed. In Comparative Examples 5 and 6, magnetic disks were manufactured in the same manner as in Example 23 except that the substrate heating temperature and the Ar gas pressure during the formation of the CrMo-based underlayer 2c and the CrMo nonmagnetic intermediate layer 4 were changed.

A running test of the magnetic disk thus obtained was performed at a head flying height of 0.075 μm or less. As a result, it was good. Then, the coercive force (Hc), the product of the residual magnetization film thickness (Mrδ), and the S / N ratio were evaluated. Note that S
The measurement of the / N ratio was performed in the same manner as in Example 1. Table 2 shows the results. Further, the composition and thickness of the CrMo underlayer 2c, the composition and thickness of the CrMo non-magnetic intermediate layer 4,
The substrate heating temperature and the Ar gas pressure at the time of manufacturing the Mo underlayer 2c and the CrMo nonmagnetic intermediate layer 4 and the crystal lattice plane spacing of the (002) plane of the CoPtCr magnetic layer 3 indicate that CrM in contact with the MoP.
o The difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the (110) plane of the underlayer 2c, and the CoPtCr magnetic layer 5
Of the (002) plane of the crystal lattice
Table 2 shows the difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the (110) plane of the Mo nonmagnetic intermediate layer 4.

[0062]

[Table 1]

[0063]

[Table 2]

As can be seen from Tables 1 and 2, Examples 1 to
The underlayer 2c and the nonmagnetic intermediate layer 4 shown in FIG.
The magnetic recording medium made of an alloy has a coercive force (Hc), a remanence film thickness product (Mrδ), and an S / N ratio which are lower than those of the magnetic recording medium of Comparative Example 1 in which the underlayer 2c and the nonmagnetic intermediate layer 4 are Cr. Large ratio.

Further, the magnetic recording medium in which the underlayer 2c and the nonmagnetic intermediate layer 4 shown in Examples 26 to 29 were made of a CrMoZr alloy was the same as the underlayer 2c and the nonmagnetic intermediate layer 4 of Comparative Example 1.
Has a larger coercive force (Hc), a product of a residual magnetization film thickness (Mrδ), and an S / N ratio than a magnetic recording medium in which is represented by Cr. In particular, when Zr is added to the CrMo alloy, the noise reduction effect is further enhanced, so that the S / N ratio is improved. In order to obtain such an effect, the content of Zr should be 2 to 5 at.
% Is preferable.

Further, based on the crystal lattice spacing of the (002) plane of the first magnetic layer 3, the (110)
Difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the planes
The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the (110) plane of the nonmagnetic intermediate layer 4 adjacent thereto from the crystal lattice spacing of the (002) plane of the second magnetic layer 5 is obtained. , Base layer 2
c, composition of the nonmagnetic intermediate layer 4, substrate heating temperature and A
It can be seen from the comparison between Examples 1 to 29 and Comparative Examples 2 to 6 that the pressure varies with the r gas pressure. For example, in the magnetic recording medium of Comparative Example 2, since each of the Mo contents of the CrMo alloy of the underlayer 2c and the nonmagnetic intermediate layer 4 was 25 at%, each (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) was −0. .014
As a result, the S / N ratio decreased as compared with the magnetic recording media of Examples 1 to 29. The result is
₍₀₀₂₎ -d ₍₁₁₀₎ ) in the predetermined range of the present invention, it is necessary that the underlayer 2c and the nonmagnetic intermediate layer 4 be made of M
This indicates that the o content is preferably 2 to 20 at%.

Further, from the results of Comparative Examples 3 to 6, (d
It can be seen that ₍₀₀₂₎ −d ₍₁₁₀₎ ) changes greatly depending on the substrate heating temperature and the Ar gas pressure. This is presumably because lattice distortion occurs in the film depending on the film production conditions, and lattice distortion in the film changes due to changes in the substrate heating temperature and the Ar gas pressure. From this, (d ₍₀₀₂₎ −
d ₍₁₁₀₎ ) is adjusted by adjusting the substrate heating temperature and the Ar gas pressure together with the Mo content of the CrMo-based underlayer 2 c and the nonmagnetic intermediate layer 4, so that each (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) can be obtained. It shows that it can be within the scope of the present invention.

In Comparative Examples 3 and 4, although the composition ratio and the film thickness of the underlayer 2c and the non-magnetic intermediate layer 4 were the same as those in Example 1, the magnetic layers were manufactured with different substrate heating temperatures and different Ar gas pressures. It is a disk. In Comparative Example 3, (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) was 0.035 due to a decrease in the substrate heating temperature, and as a result, Hc and S / N ratio were reduced. Comparative Example 4
Then, due to the increase in the Ar gas pressure, (d ₍₀₀₂₎ -d
₍₁₁₀₎ ) is 0.037, so that Mrδ and S
/ N ratio decreased. Comparative Examples 5 and 6 are magnetic disks manufactured with the same composition ratio and film thickness of the underlayer 2c and the non-magnetic intermediate layer 4 as in Example 23, but with different substrate heating temperatures and different Ar gas pressures. . In Comparative Example 5, (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) became -0.004 due to the increase in the substrate heating temperature, and as a result, Mr δ and the S / N ratio decreased. In Comparative Example 6, (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) was -0.006 due to the decrease in Ar gas pressure, and as a result, Hc and S / N ratio decreased.

Examples 30 to 46 A magnetic disk was manufactured in the same manner as in Example 1 except that the combination of the composition ratio of the CrMo base layer 2c and the composition ratio of the CrMo nonmagnetic intermediate layer 4 was changed as shown in Table 3. did. A running test of the magnetic disk thus obtained was performed at a head flying height of 0.075 μm or less. As a result, it was good. Then, the coercive force (Hc) and the product of the residual magnetization film thickness (Mr
δ) and the S / N ratio were evaluated. The measurement of the S / N ratio was performed in the same manner as in Example 1. The results are shown in Table 3 together with the conditions.

[0070]

[Table 3]

As can be seen from Table 3, the Mo content was 2 to
It can be seen that the combination of the 20 at% CrMo underlayer 2 c and the CrMo nonmagnetic intermediate layer 4 has large values of Hc, Mr δ, and S / N ratio. Preferred combinations of composition ratios for increasing the S / N ratio include Mo content of 2 to 2
Mo content of 5 to 10 relative to 0 at% CrMo underlayer
at% CrMo non-magnetic intermediate layer and Mo content 2-20 at% CrMo non-magnetic intermediate layer
This is a combination of a CrMo underlayer having a content of 5 to 10 at%. The most preferable combination having a larger S / N ratio is a combination of a CrMo nonmagnetic intermediate layer having a Mo content of 5 to 10 at% with a CrMo underlayer having a Mo content of 5 to 10 at%.

Examples 47 to 64 In Examples 47 to 56, the combinations of the composition ratio of the magnetic layer 3, the composition ratio of the CrMo base layer 2c, and the composition ratio of the CrMo nonmagnetic intermediate layer 4 were changed as shown in Table 4. A magnetic disk was produced in the same manner as in Example 1 except for the above. Example 57-
In No. 64, a magnetic disk was prepared in the same manner as in Example 1 except that the material and composition ratio of the magnetic layer 3, the composition ratio of the CrMo underlayer 2c, and the composition ratio of the CrMo non-magnetic intermediate layer 4 were changed as shown in Table 4. Produced.

The running test of the magnetic disk thus obtained was performed at a head flying height of 0.075 μm or less. As a result, it was good. Then, the coercive force (Hc), the product of the residual magnetization film thickness (Mrδ), and the S / N ratio were evaluated. The results are shown in Table 4 together with the conditions. Note that, as in Table 1, Co
The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the (110) plane of the CrMo underlayer 2c in contact with the crystal lattice spacing of the (002) plane of the PtCr magnetic layer 3 and the CoP
The difference (d ₍₀₀₂₎ -d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the (110) plane of the CrMo nonmagnetic intermediate layer 4 adjacent to the (002) crystal lattice spacing of the tCr magnetic layer 5 is Manufacturing conditions of underlayer 2c and nonmagnetic intermediate layer 4 and magnetic layer 3
Since the manufacturing conditions of the magnetic layer 5 and the magnetic layer 5 were the same, they were the same, and Table 4 shows only one value for both.

[0074]

[Table 4]

As can be seen from Table 4, the underlayer 2c and the non-magnetic intermediate layer 4 have a CrMo content of 5 to 10 at%.
When an alloy is used and the magnetic layer is a CoPtCr alloy (see Examples 47 to 56), the Co content is 60 to 90a.
t%, Pt content 4 to 20 at%, Cr content 3 to
By setting the content to 30 at%, a high Hc and a high S / N ratio can be obtained. Further, in order to obtain a high Hc and a high S / N ratio, the Co content of the CoPtCr alloy magnetic layer is 64 to 84%.
It is appropriate to set the Pt content to 5 to 18 at% and the Cr content to 5 to 25 at%.

When the magnetic layer is a CoPtTa alloy (see Examples 57 to 60), the Co content is 80 to 90 at.
%, Pt content 5-15 at%, Ta content 1-7.
By setting at%, a high Hc and a high S / N ratio can be obtained. When the magnetic layer is a CoPtCrTa alloy (Example 6)
1 to 64), Co content 70 to 80 at%, Pt content 5 to 15 at%, Cr content 5 to 25 at%, Ta
By setting the content to 1 to 7 at%, a high Hc and a high S / N ratio can be obtained.

Test Example (Overwriting Evaluation Test) The overwriting characteristics (OW (dB)) of the magnetic disk were evaluated. The evaluation method is as follows. (Overwriting evaluation method) Writing at 3.4 MHz. The output and V _1. Overwritten at 13.5 MHz. After overwriting, obtaining the output V ₂ of the written signal at 3.4MHz. OW (dB) was determined by the following equation. OW (dB) = 20 log (V ₂ / V ₁ ) The flying height of the magnetic head and the MR (magnetoresistive) head used are the same as those used in the first embodiment.

In Examples 5, 11, and 65 to 70 and Comparative Examples 1 and 7 to 12, the film thickness of the magnetic layer, the composition ratio of the underlayer and the non-magnetic intermediate layer, and the film thickness were changed. In the same manner as in Example 1, a magnetic disk was produced. The overwriting characteristics (OW) of each of the obtained magnetic disks were evaluated. In general, the overwrite characteristic (OW) shows a tendency that its absolute value increases and saturates as the write current increases, so the OW value this time is a saturated value. Table 5 shows the results together with the composition and thickness of the magnetic layer, the composition and thickness of the underlayer, and the composition and thickness of the non-magnetic intermediate layer.

[0079]

[Table 5]

As can be seen from Table 5, the underlayer and the nonmagnetic intermediate layer shown in Examples 5, 11 and 65 to 70 were formed of CrM.
It can be seen that the one using the o-alloy has much better overwriting characteristics than the one using Cr of Comparative Example 1. It can also be seen that the overwriting characteristics vary greatly depending on the thicknesses of the magnetic layer, the underlayer and the non-magnetic intermediate layer. −38
In order to have the overwriting characteristic of (dB) or more, the thickness of the magnetic layer is 230 ° or less, the thickness of the underlayer is 150 ° or less,
The thickness of the non-magnetic intermediate layer is preferably set to 100 ° or less. More preferably, the thickness of the magnetic layer is 150 ° or less, the thickness of the underlayer is 100 ° or less, and the thickness of the nonmagnetic intermediate layer is 80 ° or less.
The following is appropriate.

[0081]

According to the present invention, the conventional Cr underlayer, C
r Excellent magnetostatic characteristics (coercive force, residual magnetization film thickness product) and recording / reproducing characteristics (S / N ratio, O / O ratio) as compared to a magnetic disk composed of a combination of a r non-magnetic intermediate layer and a CoPt-based alloy magnetic film.
W), it is possible to provide a magnetic disk having a large output, a small medium noise and an excellent overwriting characteristic even in recording and reproduction at a surface recording density of 600 Mb / in ² or more.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a magnetic disk according to the present invention.

FIG. 2 is a schematic diagram of an in-line type sputtering apparatus used in the present embodiment.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Jun Nozawa 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo Inside Hoya Co., Ltd. (56) References JP 5-325163 (JP, A) JP JP-A-7-21523 (JP, A) JP-A-7-134820 (JP, A) JP-A-8-227525 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 5 / 66 G11B 5/85 H01F 10/16 H01F 10/30

Claims (15)

(57) [Claims] 1. A magnetic recording medium having a non-magnetic underlayer and a CoPt-based magnetic layer group in this order on a substrate, wherein the CoPt-based magnetic layer group is composed of two or more magnetic layers. A nonmagnetic intermediate layer made of a material containing Cr and Mo as main components, and based on the crystal lattice spacing of the hcp (002) plane of the magnetic layer, Cr and Mo immediately below the magnetic layer are used as main components. The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the bcc (110) plane of the nonmagnetic intermediate layer made of
A magnetic recording medium having a range of 0.032 angstroms. 2. The method according to claim 1, wherein the magnetic layer has two or more non-magnetic intermediate layers, and each non-magnetic intermediate layer has Cr and Mo immediately below the magnetic layer based on the crystal lattice spacing of the hcp (002) plane of the magnetic layer. Bcc (11
Difference obtained by subtracting the crystal lattice spacing of the (0) plane (d ₍₀₀₂₎ −
2. The magnetic recording medium according to claim 1, wherein d ₍₁₁₀₎ ) is in the range of 0.002 to 0.032 angstroms. 3. A crystal lattice of a bcc (110) plane of a nonmagnetic intermediate layer made of a material containing Cr and Mo as a main component immediately below the magnetic layer from a crystal lattice plane spacing of an hcp (002) plane of the magnetic layer. The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) obtained by subtracting the plane distance is equal to 0.
The magnetic recording medium according to claim 1, wherein the magnetic recording medium has a range of 014 to 0.030 angstroms. 4. A non-magnetic intermediate layer comprising two or more non-magnetic intermediate layers, wherein each of the non-magnetic intermediate layers is independently formed of Cr and Mo immediately below the magnetic layer based on the crystal lattice spacing of the hcp (002) plane of the magnetic layer. Bcc (11
Difference obtained by subtracting the crystal lattice spacing of the (0) plane (d ₍₀₀₂₎ −
2. The magnetic recording medium according to claim 1, wherein d ₍₁₁₀₎ ) is in the range of 0.014 to 0.030 angstroms. 5. A magnetic recording medium having a non-magnetic underlayer and a CoPt-based magnetic layer group in this order on a substrate, wherein the CoPt-based magnetic layer group is composed of two or more magnetic layers. A nonmagnetic intermediate layer made of a material containing Cr and Mo as main components, and based on the crystal lattice spacing of the hcp (002) plane of the magnetic layer, Cr and Mo immediately below the magnetic layer are used as main components. The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the bcc (110) plane of the nonmagnetic intermediate layer made of
0.032 angstroms, wherein the nonmagnetic underlayer is composed of one or more layers, and the nonmagnetic underlayer immediately below the lowermost magnetic layer of the CoPt-based magnetic layer group contains Cr and Mo. From the crystal lattice spacing of the hcp (002) plane of the lowermost magnetic layer of the magnetic layer group, the nonmagnetic underlayer bcc ( The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) obtained by subtracting the crystal lattice spacing of the (110) plane is 0.00
A magnetic recording medium having a range of 2 to 0.032 angstroms. 6. A non-magnetic intermediate layer comprising two or more non-magnetic intermediate layers, wherein each of the non-magnetic intermediate layers is independently formed of Cr and Mo immediately below the magnetic layer based on the crystal lattice spacing of the hcp (002) plane of the magnetic layer. Bcc (11
Difference obtained by subtracting the crystal lattice spacing of the (0) plane (d ₍₀₀₂₎ −
6. The magnetic recording medium according to claim 5, wherein d ₍₁₁₀₎ ) is in the range of 0.002 to 0.032 angstroms. 7. A crystal lattice of a bcc (110) plane of a nonmagnetic intermediate layer made of a material mainly composed of Cr and Mo immediately below the magnetic layer based on a crystal lattice plane spacing of an hcp (002) plane of the magnetic layer. The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) obtained by subtracting the plane distance is equal to 0.
6. The magnetic recording medium according to claim 5, wherein the range is from 014 to 0.030 angstroms. 8. A non-magnetic intermediate layer comprising at least two non-magnetic intermediate layers, wherein each of the non-magnetic intermediate layers is independently formed of Cr and Mo immediately below the magnetic layer based on the crystal lattice spacing of the hcp (002) plane of the magnetic layer. Bcc (11
Difference obtained by subtracting the crystal lattice spacing of the (0) plane (d ₍₀₀₂₎ −
6. The magnetic recording medium according to claim 5, wherein d ₍₁₁₀₎ ) is in the range of 0.014 to 0.030 angstroms. 9. A difference crystal obtained by subtracting a crystal lattice spacing of a bcc (110) plane of a nonmagnetic underlayer made of a material mainly composed of Cr and Mo from a crystal lattice spacing of an hcp (002) plane of a magnetic layer. The difference (d ₍₀₀₂₎ −d ₍₁₁₀₎ ) in the lattice spacing is 0.
9. The magnetic recording medium according to claim 5, wherein the magnetic recording medium has a range of 014 to 0.030 angstroms. 10. A non-magnetic underlayer made of a material mainly composed of Cr and Mo and one or more non-magnetic underlayers between a substrate and said non-magnetic underlayer mainly composed of Cr and Mo. 10. The magnetic recording medium according to claim 5, wherein the nonmagnetic underlayer in contact with the nonmagnetic underlayer made of a material is made of a metal having a body-centered cubic crystal structure. 11. The magnetic recording medium according to claim 10, wherein the nonmagnetic underlayer made of a metal having a body-centered cubic crystal structure is a Cr layer. 12. The magnetic recording medium according to claim 1, wherein the CoPt-based magnetic layer is a CoPtCr alloy magnetic layer. 13. The CoPtCr alloy has a Co content of 60 to 90 at%, a Pt content of 4 to 20 at%, and C
The magnetic recording medium according to claim 12, wherein the content of r is 3 to 30 at%. 14. The method for manufacturing a magnetic recording medium according to claim 1, wherein the CoPt-based magnetic layer group and a non-magnetic layer composed of a material containing Cr and Mo as main components. The magnetic intermediate layer is heated at a substrate heating temperature range of 250 ° C.
To 425 ° C, and the Ar gas pressure range is 0.5 to 10 mT
A method for manufacturing a magnetic recording medium, wherein orr is formed by a sputtering method. 15. The method for manufacturing a magnetic recording medium according to claim 5, wherein a nonmagnetic underlayer made of a material containing at least Cr and Mo as a main component, and a CoPt-based magnetic layer group. And a non-magnetic intermediate layer made of a material containing Cr and Mo as main components, the substrate heating temperature range is set to 250 ° C. to 425 ° C., and the Ar gas pressure range is set to 0.5.
A method for manufacturing a magnetic recording medium, wherein the magnetic recording medium is formed by sputtering at a pressure of 10 to 10 mTorr.