JP2003016625A - Magnetic recording medium, its manufacturing method and magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording medium in which thermal demagnetization due to thermal fluctuation hardly occurs and which is excellent in SNR in high density recording and to provide its manufacturing method and a magnetic recording and reproducing device. SOLUTION: The magnetic recording medium is constituted of at least a nonmagnetic substrate, a nonmagnetic substrate layer, a magnetic layer and a protective layer and is characterized by that the magnetic layer contains a Co alloy, is separated to a large number of magnetic films by a layer containing CoRu bonding, at least a pair of magnetic films holding the layer containing the CoRu bonding therebetween are magnetized in the same directions when magnetized or a magnetization curve has no level difference and a Mr t value is smaller by 5 to 15% than that of the magnetic recording medium having the same film thickness of the Co alloy. Thereby SNR is improved and the obtained magnetic recording medium is suitable for high density recording. Further the magnetic recording and reproducing device of this invention uses the magnetic recording medium described above and thereby is suitable for high density recording.

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 used in a hard disk device, a method for manufacturing the magnetic recording medium, and a magnetic recording / reproducing apparatus.
In particular, the present invention relates to those having excellent recording and reproducing characteristics.

[0002]

2. Description of the Related Art A hard disk drive (HDD), which is one type of magnetic recording / reproducing apparatus, currently has an annual recording density of 60.
%, And that trend is said to continue.
A magnetic recording head suitable for high recording density and a magnetic recording medium are being developed. The magnetic recording medium used therein is required to have a high recording density, and accordingly, improvement of coercive force and reduction of medium noise are required.

As a magnetic recording medium for a hard disk device, one having a structure in which metal thin films are laminated by a film forming method by a sputtering method is predominant. Aluminum substrates and glass substrates are generally widely used as substrates for the magnetic recording medium. It has been examined that the substrate has smoothness and flatness that can be applied to a high recording density in which the flying height of the head is reduced. Since the glass substrate has rigidity with excellent impact resistance, its practical application has been studied. The aluminum substrate is obtained by applying NiP or NiP alloy to a thickness of about 10 μm on the surface of a substrate made of a mirror-polished AlMg alloy by electroless plating and further finishing it to a mirror surface. Glass substrates include amorphous glass and crystallized glass. A nonmagnetic underlayer and a magnetic layer are formed in this order on these substrates. C as a non-magnetic underlayer
An r or Cr alloy and a Co alloy are mainly used for the magnetic layer. The composition of the non-magnetic underlayer is such that when the Cr or Cr alloy layer is a single layer, it is composed of different compositions.
There are also cases of three layers. When the Co alloy that is the magnetic layer is also one layer, two layers of different compositions are used, and three layers
There may be layers.

Co alloy is generally used for the magnetic layer, and the alloy composition is CoCrNi, CoCrTa, C.
oCrPtTa and CoCrPtB have been developed and put into practical use in this order. CoCrPtB alloys are predominant for magnetic recording media exceeding the recording density of 10 Gb / (inch) ² .

In order to further increase the magnetic recording density, SNR (Signal to No) when recording and reproducing at high frequency is performed.
There is a demand for improving the "Ise Ratio", and for that purpose, there has been a demand for a magnetic recording medium with further reduced noise. The grain size of the crystal grains of the alloy of the magnetic layer is a major factor that determines the noise of the magnetic recording medium, and miniaturization of the crystal grains has been studied by devising the formation method and composition of the non-magnetic underlayer and the magnetic layer. A Co alloy having a crystal grain size of about 10 nm is obtained.

Further, since the sensitivity of the head has been improved, the thickness of the magnetic layer has been reduced. As the magnetic layer becomes thinner, the full width at half maximum (PW50) of the isolated reproduction waveform becomes smaller, and the overwrite (OW) characteristic and SNR characteristic are improved. At present, the thickness of the Co alloy layer is about 15 nm.

As described above, the grain size of the Co alloy crystal grains has become smaller and the thickness of the Co alloy layer has also become smaller.
The volume of crystal grains of o alloy has become very small. By the way, a ferromagnetic substance has a Curie temperature as its physical property, and becomes a paramagnetic substance at a temperature higher than that. That is, as the temperature rises, it becomes impossible to maintain ferromagnetism due to fluctuations due to heat. Here, it has been known that when the size of the ferromagnetic material is smaller than about 10 nm in diameter, the same phenomenon as the Curie temperature is lowered occurs. That is, there has been a problem that the Co alloy cannot maintain ferromagnetism due to thermal fluctuation even at room temperature. This phenomenon is called thermal demagnetization.

The susceptibility of the thermal demagnetization phenomenon has a trade-off relationship with the grain size of the crystal grains and the tendency of the film thickness of the magnetic layer as the recording density is improved. Since the size of the grain size and the thickness of the Co magnetic layer have already approached the limit of occurrence of thermal demagnetization, it has become difficult to further increase the recording density.

Under such a circumstance, a magnetic recording medium in which thermal demagnetization does not easily occur even if crystal grains are made small by using a CoRu layer, for example, has been studied. CoRu coupling contained in the CoRu layer causes antiferromagnetism. Shimesu. When the crystal exhibiting antiferromagnetism is in contact with the crystal of the Co alloy that is ferromagnetic, the magnetization of the Co alloy is reduced because the magnetization is canceled by the influence of the antiferromagnetism. When this state is viewed from the head, the portion of the Co alloy crystal grains that contributes to the magnetization is small, so the portion that is actually magnetically recorded feels like a very thin crystal grain, and the fluctuation due to heat Is considered to be in a state in which thermal demagnetization is unlikely to occur because the volume of the entire magnetic layer including those exhibiting antiferromagnetism can be considered.

On the other hand, by providing a separation layer composed of a non-magnetic layer in the Co alloy layer, the magnetic exchange coupling of the crystal grains of the Co alloy sandwiching the separation layer is cut, and as a result, the means for improving the SNR is special. It is proposed in Japanese Laid-Open Patent Publication No. 63-146219. Here, Al ₂ O ₃ and Si are used as the separation layer.
It is disclosed to provide O ₂ and Cr films.

EP 0892393A1 discloses that as the crystal orientation of the Co alloy, only the Co alloy (100) plane is advantageous for inserting the separation layer. BCC as the separation layer,
B2 structure having (112) plane, Co,
It has been proposed that an alloy with an HCP (100) structure containing Cr, Ru, Re and Os be good. Alternatively, JP-A-1
In JP-A-328646, Co alloy (100)
It is said that the B2 structure is effective as the separation layer not only on the surface but also on the Co alloy (110) surface. Further, NiAl and NiAlRu have been proposed as the spacer layer. Although not a B2 structure, a nonmagnetic Ru single layer having a film thickness of 0.3 to 3 nm is also proposed to be effective.

[0012]

A means for improving the SNR by cutting the magnetic exchange coupling of the crystal grains of the Co alloy sandwiching the separation layer by providing the separation layer in the Co alloy layer is described below.
If the thickness of the non-magnetic layer is increased to sufficiently cut the magnetic exchange coupling, the crystal orientation and crystallinity of the uppermost Co alloy layer of the separated magnetic layers will be insufficient and the magnetic characteristics (coercive force (H
Since c) and S *) are decreased and the residual magnetization is decreased, the reproduction output is decreased. That is, in order to break the magnetic coupling of the magnetic layer, the film thickness of the nonmagnetic layer needs to be 2 nm or more.
Crystal orientation is disturbed and it becomes difficult to maintain epitaxy growth, and the crystal orientation of the top Co alloy layer is not aligned in the plane, resulting in insufficient magnetic properties and a large decrease in coercive force. There was a fear.

On the other hand, in the method in which the CoRu coupling is provided in the Co alloy layer as in the conventional technique, the magnetic layer separated by the CoRu coupling is antiferromagnetically coupled while the thickness of the entire Co alloy layer is increased. The magnetic film thickness that contributes to magnetic recording and reproduction is reduced by canceling out the magnetic field by reducing Mrt (magnetization (Mr) and film thickness (t)).
Product of Although the reproduction output is reduced as a result of reducing the value of (1), the noise of the magnetic recording medium can be reduced and the PW50 can be reduced. However, while the SNR is determined by the ratio of the reproduction output and noise, the volume of each magnetic particle is small, so the noise can be reduced, but the number of magnetic particles per unit volume does not change. Therefore, the improvement of SNR was insufficient.

The present invention has been made in view of the above circumstances, and is a magnetic recording medium capable of coping with a higher recording density, having a higher coercive force and an improved SNR,
It is an object of the present invention to provide a manufacturing method thereof and a magnetic recording / reproducing device.

[0015]

In order to solve the above-mentioned problems, the inventors of the present invention completed the present invention by thoroughly studying the relationship between a magnetic layer having another layer in a Co alloy layer and recording / reproducing characteristics. did. 1) A first invention for solving the above-mentioned problems is to provide a magnetic recording medium comprising at least a non-magnetic substrate, a non-magnetic underlayer, a magnetic layer and a protective film, wherein the magnetic layer contains a Co alloy and has a CoRu bond. The magnetic recording medium is characterized in that it is divided into a large number of magnetic films by the containing layer, and when the magnetic films sandwiching at least one set of layers containing CoRu coupling are magnetized in the same direction. 2) A second invention for solving the above-mentioned problems is to provide a magnetic recording medium comprising at least a non-magnetic substrate, a non-magnetic underlayer, a magnetic layer and a protective film, wherein the magnetic layer contains a Co alloy and has a CoRu bond. The magnetic recording medium is characterized in that it is separated into a large number of magnetic films by the containing layer, and that the value of Mrt is 5 to 15% smaller than that of a magnetic recording medium in which there is no step in the magnetization curve and the film thickness of the Co alloy is the same. 3) A third invention for solving the above problems is CoRu.
The magnetic recording medium as described in 1) or 2), wherein the thickness of the layer containing a bond is 0.3 to 1.5 nm. 4) A fourth invention for solving the above-mentioned problems is CoRu.
4. The magnetic recording medium according to any one of 1) to 3), wherein the Co-containing layer has a Co content of 30 to 50 at% and a Ru content of 25 to 60 at%. is there. 5) A fifth invention for solving the above-mentioned problems is characterized in that, of the separated magnetic films, the second magnetic film from the surface of the magnetic recording medium has a thickness of 5 nm or more 1) to 4 (4) The magnetic recording medium according to any one of (1). 6) A sixth invention for solving the above-mentioned problems is characterized in that the total thickness of the magnetic layer is 25 nm or less. 1)
The magnetic recording medium according to any one of 1 to 5). 7) A seventh invention for solving the above-mentioned problems, wherein the non-magnetic substrate is a glass substrate, on which a NiAl layer and CrM are provided.
Multi-layer non-magnetic underlayer composed of o-based alloy layer, CoCr
Any of 1) to 6), characterized in that it has a non-magnetic intermediate layer made of an alloy and a magnetic layer made of a CoCrPB-based alloy having at least one set of layers containing CoRu bonds therein. The magnetic recording medium according to item 1. 8) An eighth invention for solving the above-mentioned problems is a substrate in which a non-magnetic substrate has a film made of NiP on a surface of an AlMg alloy substrate, and has a multilayer structure of a Cr layer and a CrMo-based alloy. 1) A magnetic underlayer, a non-magnetic intermediate layer made of a CoCr alloy, and a magnetic layer made of a CoCrPtB-based alloy having at least one set of layers containing CoRu bonds therein 1) 1 to 6)
The magnetic recording medium according to the item 1. 9) A ninth invention for solving the above-mentioned problems is CoRu.
A layer containing a bond is formed by using a sputtering target using a material containing a composition having a Co content of 30 to 50 at% and a Ru content of 25 to 60 at%, and a magnetic layer having a CoRu bond. A method of manufacturing a magnetic recording medium, in which a plurality of magnetic films are separated by a containing layer and at least one set of magnetic films sandwiching a layer containing CoRu coupling is formed so as to be magnetized in the same direction when magnetized. 10) A tenth invention for solving the above-mentioned problems is Co
A layer containing Ru bonds is formed by forming a Co alloy film and then stacking Ru on it for 0.5 to 1 nm to divide the magnetic layer into a large number of magnetic films by the layer containing CoRu bonds, and It is a method of manufacturing a magnetic recording medium in which at least one set of magnetic films sandwiching a layer containing CoRu coupling is magnetized in the same direction when magnetized. 11) An eleventh invention for solving the above-mentioned problems is Co
After forming the Co alloy film, the layer containing Ru bond
Of 0.1 to 0.3 nm and Ru of 0.5 to 1 nm are continuously laminated, the magnetic layer is divided into a large number of magnetic films by a layer containing CoRu bonds, and a layer containing CoRu bonds. It is a method of manufacturing a magnetic recording medium in which at least one set of magnetic films sandwiching the above is formed so as to be magnetized in the same direction when magnetized. 12) A twelfth invention for solving the above-mentioned problems is a magnetic recording / reproducing apparatus comprising a magnetic recording medium and a magnetic head for recording / reproducing information on / from the magnetic recording medium, wherein the magnetic recording medium is 1). (8) to (8), which is the magnetic recording medium according to any one of (1) to (8).

The operation of the present invention will be described below. In the present invention, a thin layer containing CoRu coupling having antiferromagnetism is provided in the magnetic layer to separate the magnetic layers. as a result,
It is possible to improve the SNR without decreasing the coercive force without decreasing the reproduction output, prevent the PW50 from deteriorating to the minimum, and suppress the thermal demagnetization to a level within which there is no problem.

Since CoRu coupling is antiferromagnetic, it is magnetized in the opposite direction to the direction of the applied external magnetic field (FIG. 2). As shown in FIG. 3, when the layer under CoRu coupling is thin, it is strongly influenced by the antiferromagnetism of CoRu coupling, so that the entire layer exhibits antiferromagnetism, that is, the direction opposite to the external magnetic field. It comes to show magnetization. On the other hand, as shown in FIG. 1, in the present invention, since the lower layer is sufficiently thick (for example, 5 nm or more), the layer has the effect of the CoRu coupling, and exhibits the original ferromagnetic property and is magnetized in the same direction as the magnetic field. And magnetize in the same direction as the upper layer. Therefore, the upper layer and the lower layer contribute to recording and reproduction, and the reproduction output becomes large. As a result, the reproduced signal output becomes large, so that SN
R (Signal to Noise Ratio) is improved.

On the other hand, in this case, the CoRu coupling portion is a thin (for example, 1 nm or less) antiferromagnetic layer. As a result, since a layer exhibiting opposite magnetization is provided in the middle of the Co alloy layer, magnetic coupling can be separated even if the film thickness is thin. As a result, it can be inferred that the upper film and the lower film have the same magnetization direction but weak magnetic coupling with each other. As a result, noise is reduced. As a result, the noise is reduced and the SNR is further improved.

The layer containing CoRu coupling according to the present invention may have a small film thickness necessary for breaking the magnetic coupling, so that the film thickness maintains the crystal orientation and crystallinity between the Co magnetic films sandwiching it. It will be what you did. As a result, for example, the first Co alloy film from the surface can sufficiently maintain the crystal orientation and crystallinity of the magnetic film formed thereunder, and the coercive force Hc, S
* Can suppress the decrease.

Further, in the case where the magnetic coupling is cut by providing the non-magnetic layer, the required film thickness becomes thicker,
When the total thickness of the Co alloy magnetic film is the same, the remanent magnetization is not reduced and the reproduction output during recording / reproduction does not decrease.

Layers containing CoRu alloys typically include Co
Although the Ru coupling, the CoCo coupling, and the RuRu coupling are included, the layer containing the CoRu coupling of the present invention exhibits sufficient antiferromagnetism and thus contains the CoRu coupling as the main component. The main component is a component exceeding 50 at%.
Further, it is considered preferable that the bonding directions are arranged in layers in a direction substantially parallel to the substrate surface.

When separated by the introduction of a non-magnetic separation layer which is a conventional technique, the Mr expected from the thickness of the Co alloy is
Comparing the value of t with the actual value of Mrt, the values are almost the same. On the other hand, when the Co magnetic layer is separated by the layer containing CoRu bonds according to the present invention, the actual Mrt value is better than the actual Mrt value predicted from the thickness of the Co alloy by comparison. It is reduced by about 0.2 to 0.3 memu / cm ² . That is, since CoRu coupling is formed, the actual value of Mrt is reduced by the amount of antiferromagnetism. On the other hand, when simply inserting the Ru layer,
The Ru layer merely acts as a separation layer which is non-magnetic, and thus Co
The value of Mrt expected from the thickness of the alloy layer and the actual Mrt
It can be confirmed that the values of are the same. Since the magnitude of Mrt has a proportional relationship with the magnitude of the reproduction output signal, a similar difference appears in the magnitude of the reproduction output signal. However, in the present invention, since the noise reduction is larger than the reproduction signal reduction, the SNR can be improved as a result.

Further, according to the present invention, since the layer containing CoRu bond is thin, the volume of the Co magnetic film sandwiching the CoRu bond is small as a whole, including the one exhibiting antiferromagnetic property against fluctuation due to heat. Since it can be considered, thermal demagnetization is unlikely to occur. Also, at least one of the separated magnetic films
Since the thickness of the film, for example, the second magnetic film from the surface of the magnetic recording medium is increased, it is more thermally stable.

[0024]

FIG. 4 shows an embodiment of a magnetic recording medium of the present invention. The magnetic recording medium shown here is
On the non-magnetic substrate 1, a non-magnetic underlayer 2, a non-magnetic intermediate layer 3,
The magnetic layer 4, the protective film 5, and the lubricating layer 6 are sequentially formed.

The non-magnetic substrate in the present invention is an Al alloy having a NiP plating film which is generally used as a substrate for magnetic recording media (hereinafter referred to as NiP plating Al.
Also called a substrate. ), The non-magnetic substrate is made of a non-metal material such as glass, ceramics, silicon, silicon carbide, carbon, or resin, and a film of NiP or NiP alloy is formed on the substrate of these non-metal materials. I can list the things I did.

As the recording density is increased, it is required to reduce the flying height of the head. Therefore, high smoothness of the substrate surface is required. That is, the non-magnetic layer substrate used in the present invention has an average surface roughness Ra of 2 nm (20 Å) or less, preferably 1 nm or less.

As the non-metal material, it is preferable to use a glass substrate in terms of cost and durability. From the viewpoint of surface smoothness, it is preferable to use a glass substrate, a silicon substrate or the like. Crystallized glass or amorphous glass can be used for the glass substrate. As amorphous glass, general-purpose soda lime glass, aluminate glass,
Aluminosilicates can be used. As the crystallized glass, lithium-based crystallized glass can be used. From the viewpoint of being adaptable to a wider variety of usage environments, crystallized glass having excellent chemical durability is preferable. Here, the constituents of the crystallized glass containing SiO ₂ and Li ₂ O are the points of matching the thermal expansion coefficient with other parts when actually used by incorporating them into the drive device, or It is preferable in terms of rigidity during assembly and use. Examples of the ceramic substrate include a general-purpose sintered body containing aluminum oxide, silicon nitride, or the like as a main component, and fiber-reinforced products thereof.

A nonmagnetic underlayer 2 is provided on the nonmagnetic substrate 1. The non-magnetic underlayer 2 is made of CrTi alloy, CrW
It is preferable to use a material containing one or more selected from the group-based alloys, CrMo-based alloys, CrV-based alloys, CrSi-based alloys and Ni ₅₀ Al ₅₀ .

The film thickness of the non-magnetic underlayer of the present invention is 20-40.
The range is preferably 0 nm (preferably 50 to 300 nm). This is because if it is less than 20 nm, the crystal growth is not sufficiently performed, and if it exceeds 400 nm, the crystal grains grow large.

In order to maximize the effect of the present invention, since Cr has a small lattice constant, CrMo, Cr
It is preferable to add Mo, W, V, etc. such as W, CrV to widen the lattice constant of Cr so as to match the Co alloy of the lattice magnetic layer.

The nonmagnetic underlayer in the present invention preferably has a multilayer structure from the viewpoint of SNR. In that case, as the composition, the same kind or different kinds of combinations selected from the above can be mentioned.

The magnetic layer provided on the non-magnetic underlayer 2 may be a Co alloy containing Co as a main raw material and having a hcp structure. For example, CoCrTa
It is possible to include any one selected from the group-based alloys, CoCrPt-based alloys, CoCrPtTa-based alloys, CoCrPtB-based alloys, CoCrPtBTa-based alloys, and CoCrPtBCu-based alloys. A material containing Pt and B is preferable because a high coercive force can be obtained.

When a glass substrate is used as the non-magnetic substrate, a NiAl layer is formed by, for example, the sputtering method, and a layer made of Cr or Cr alloy is formed as the non-magnetic underlayer by, for example, the sputtering method and made of Co alloy. The magnetic layers are sequentially laminated. In this case, the orientation plane of Cr or Cr alloy in the non-magnetic underlayer is the (112) plane, and the orientation plane of the magnetic layer made of the Co alloy is the (100) plane.

When a NiP-plated Al substrate is used as the non-magnetic substrate, the surface of the NiP layer formed by electroless plating is textured, and then a layer made of Cr or a Cr alloy is used as the non-magnetic underlayer. A magnetic layer made of a sputter method and made of a Co alloy is sequentially laminated. In this case, the oriented surface of the Cr or Cr alloy of the non-magnetic underlayer is the (200) plane, and the oriented surface of the magnetic layer of the Co alloy is the (110) plane. The present invention is commonly effective for magnetic recording media in which the direction of easy magnetization of Co alloy is in-plane.

The magnetic layer 4 of the present invention contains a Co alloy and contains C
The magnetic films that are separated into a large number of magnetic films 8 by the layer 7 including oRu coupling and sandwich at least one set of layers including CoRu coupling are magnetized in the same direction when magnetized.

Co separated by layer 7 containing CoRu bonds
The thickness of the second film from the surface of the alloy magnetic film 8 is 5 nm.
Or more (preferably 70 nm or more). If it is less than that, the second layer is magnetized in the opposite direction of the magnetic field under the influence of CoRu coupling. That is, it exhibits antiferromagnetism. In the state where the second surface layer exhibits antiferromagnetism, the second layer does not contribute to magnetic recording, so that the output decreases. Beyond that, since it is a normal ferromagnetism without being affected by CoRu coupling, it contributes to magnetic recording and the reproduction signal output increases. In this case, since the lower layer and the upper layer sandwich the antiferromagnetic layer, the magnetic coupling is separated and different particles are formed, so that the number of particles is increased. As a result, noise is reduced and, for example, SNR of 2-3 dB is improved.

When the Co magnetic layer is cut by the layer containing CoRu coupling and the underlying magnetic film is antiferromagnetically coupled, FIG.
As shown in, the magnetization curve has a step, which is due to Co
It means a phenomenon in which the magnetic film under the layer containing Ru coupling is magnetized. However, in the present invention, since the lower magnetic film has the same direction of the magnetic field, the phenomenon of magnetization reversal of the magnetic film below the layer containing CoRu coupling does not occur, and a step is visible in the magnetization curve as shown in FIG. It's gone. The magnetization curve of the present invention has the same shape as that in which the magnetic layer is not separated by a general antiferromagnetic layer. Further in the present invention,
Since it contains anti-ferromagnetic CoRu coupling, it has a smaller Mrt than a Co alloy layer of the same thickness. When the Co alloy magnetic layer is separated by a simple non-magnetic separation layer containing no CoRu bond, Mrt is the sum of that of the upper film and that of the lower film, whereas the magnetic recording medium of the present invention is Since they are separated by CoRu coupling having antiferromagnetism, the magnetization has a value of Mrt offset by the amount of antiferromagnetism. In the magnetic recording medium of the present invention, the value of Mrt is 5 to 15% (preferably 5 to 10) as compared with the Co alloy having the same film thickness.
%. ) Characterized by being small. Since the value of Mrt and the reproduction signal output are in a proportional relationship, the small value of Mrt can be confirmed by the small value of the reproduction signal output. The magnetization curve and the value of Mrt are, for example, VSM (vibrati).
ng sample magnetometer).

The thickness of the layer containing CoRu bond is 0.3 to.
The thickness is preferably 1.5 nm (preferably 0.5 to 1.2 nm) from the viewpoint of separating the magnetic coupling of the Co alloy layer. This is because the degree of orientation deterioration is small, the coercive force is not significantly reduced, and the degree of thermal demagnetization can be suppressed to a level at which there is no problem. This is because if the thickness is less than 0.3 nm, a state in which only one CoRu bond is lined up cannot be sufficiently formed, and if the thickness exceeds 1.5 nm, the antiferromagnetic layer is too thick and the direction of magnetization of the Co alloy magnetic film below the antiferromagnetic layer is too thick. It will not be the same as the upper membrane. As a result, the underlying film is prevented from contributing to magnetic recording and reproduction.

The content of Co in the layer containing CoRu bond is 3
0 to 50 at% (more preferably 40 to 50 at%, more preferably 45 to 50 at%), and the Ru content is 25 to 60 at% (more preferably 35 to 60 a).
t%. More preferably 45 to 55 at%. ) Is preferable. The layer containing Ru provided in the above Co alloy layer does not have antiferromagnetism other than CoRu coupling.
It includes Ru bond, PtRu bond, and BRu bond. Therefore, by setting this range, a higher effect of CoRu coupling can be obtained. This is because if the Co content is less than 30 at%, the CoRu bond becomes insufficient. This is because if the Co content exceeds 50 at%, Ru will be insufficient and the CoRu bond will also be insufficient. This is because if the Ru content is less than 25 at%, the CoRu bond becomes insufficient. Ru content is 60 at%
This is because Co is insufficient and CoRu bond is also insufficient when the value exceeds.

Among the separated magnetic films, the second magnetic film from the surface of the magnetic recording medium has a thickness of 50 nm or more (more preferably 70 to 100 nm, further preferably 80 to 95).
nm. ) Is preferable. This is because if it is less than 50 nm, the coercive force required for magnetic recording at high recording density cannot be obtained. Further, the thickness of 100 nm or less is more preferable because noise can be reduced.

The total thickness of the magnetic layer is preferably 25 nm or less (preferably 7 to 20 nm). 25 nm
This is because the PW50 becomes large and it becomes unsuitable for high recording density when it exceeds. Further, it is more preferable that the film thickness of the magnetic layer is 7 nm or more because the coercive force required for magnetic recording at a higher recording density can be obtained.

The composition of the magnetic layer is preferably as follows. For example, in the case of CoCrPt system, the Cr content is 10 to 25 at% and the Pt content is 8 to 16 at%.
Is preferable from the viewpoint of SNR. For example, CoCr
In the case of PtB type, the content of Cr is 10 to 25 at%, P
The content of t is 8 to 16 at%, and the content of B is 1 to 20 a.
It is preferably t% from the viewpoint of SNR. For example, Co
In the case of CrPtBTa system, the content of Cr is 10 to 25a
t%, Pt content is 8 to 16 at%, B content is 1
From the viewpoint of SNR, it is preferable that the content of Ta is 20 at% and the content of Ta is 1 to 4 at%. For example, CoCrPtBCu
In the case of the system, the content of Cr is 10 to 25 at%, the content of Pt is 8 to 16 at%, the content of B is 2 to 20 at%,
The Cu content is preferably 1 to 4 at% from the viewpoint of SNR.

Each layer of the magnetic layer separated into multiple layers can be a combination of materials selected from the above. Immediately above the non-magnetic underlayer of the magnetic layer separated into multiple layers, it is preferable to use a CoCrPtBTa-based alloy, a CoCrPtBCu-based alloy, or a CoCrPtB-based alloy from the viewpoint of improving the SNR characteristics of the recording / reproducing characteristics. The top layer is CoCrPtBC
It is preferable to use a u-based alloy or a CoCrPtB-based alloy from the viewpoint of improving the SNR characteristics of recording / reproducing characteristics.

A nonmagnetic intermediate layer is preferably provided between the nonmagnetic underlayer and the magnetic layer for the purpose of promoting epitaxial growth of the Co alloy. Magnetic characteristics such as coercive force improving effect and recording and reproducing characteristics such as SNR improving effect can be obtained. The nonmagnetic intermediate layer may contain Co and Cr. When a CoCr alloy is used, the content of Cr is 25 to
It is preferably 45 at% from the viewpoint of SNR. The thickness of the non-magnetic intermediate layer is preferably 0.5 to 3 nm from the viewpoint of SNR.

When the magnetic layer contains B, it is preferable that the Cr concentration is 40 at% or less in the region where the B concentration is 1 at% or more near the boundary between the non-magnetic underlayer and the magnetic layer. Prevents Cr and B from coexisting at a high concentration, and suppresses the formation of a covalent bond compound of Cr and B as much as possible.
As a result, it is possible to prevent the deterioration of the orientation in the magnetic layer due to it.

Further, an orientation adjusting film made of a metal material may be provided between the substrate and the nonmagnetic underlayer for the purpose of promoting the epitaxial growth of the nonmagnetic underlayer. The thickness of the orientation adjusting film is preferably 5 to 50 nm from the viewpoint of promoting epitaxial growth. Further, an adhesion layer may be provided between the non-metal substrate and the orientation adjustment film in order to improve the adhesion between the substrate and the orientation adjustment film. Adhesion layer is Cr, Ti,
Any one selected from W can be used. The thickness of the adhesive layer is 1 to 100 nm (more preferably 5 to 80 nm).
Is. More preferably, it is 7 to 70 nm. It is preferable from the viewpoints of adhesion and productivity. FIG. 7 shows a diagram of a film configuration when the orientation adjustment film 9 and the adhesion layer 10 are provided.

The protective film 5 is made of a conventionally known material, for example,
A simple substance of carbon or SiC or a material containing them as a main component can be used. The thickness of the protective film is 1 to 10n
m is preferable from the viewpoint of spacing loss or durability when used in a high recording density state.

A lubricating layer 6 made of a known lubricant such as a fluorine-based lubricant of perfluoropolyether can be provided on the protective film, if necessary.

The non-magnetic substrate may have a texture mark on the surface by a texture treatment. The average roughness of the surface of the substrate having texture marks is 0.1
It is preferable to process so as to have a thickness of not less than 0.7 nm and not more than 0.7 nm (more preferably not less than 0.1 nm and not more than 0.5 nm, further preferably not less than 0.1 nm and not more than 0.35 nm). It is preferable that the texture marks are formed substantially in the circumferential direction in order to enhance the magnetic anisotropy in the circumferential direction of the magnetic recording medium. The texture processing can be texture processing with addition of oscillation. Oscillation is an operation of running the tape in the circumferential direction of the substrate and simultaneously swinging the tape in the radial direction of the substrate. Oscillation conditions of 60 to 1200 times / minute are preferable because the amount of surface grinding by the texture becomes uniform.

As a texture processing method, a method of forming a texture mark having a linear density of 7500 [lines / mm] or more can be used. In addition to the mechanical texture method using the above-mentioned tape, fixed abrasive grains are used. The method described above, the method using a fixed grindstone, and the method using laser processing can be used.

In the magnetic recording medium of the present invention, the magnetic layer contains a Co alloy, is separated into a large number of magnetic films by a layer containing CoRu bonds, and the magnetic films sandwiching at least one set of layers containing CoRu bonds are magnetized. Since the magnetic recording medium is characterized in that it is sometimes magnetized in the same direction, the first Co alloy layer from the surface can sufficiently maintain the crystal orientation and crystallinity, and the coercive force Hc and S * are lowered. Never again,
Compared to the case where a non-magnetic layer having a film thickness necessary for breaking the magnetic coupling is provided, the reproduction output is reduced without lowering the residual magnetization as compared with the case where the Co alloy layer has the same thickness. Since it does not decrease, the SNR is improved and the magnetic recording medium is suitable for high recording density.

FIG. 8 shows an example of a magnetic recording / reproducing apparatus using the above magnetic recording medium. The magnetic recording / reproducing apparatus shown here includes a magnetic recording medium 80 having the configuration shown in FIG. 4, a medium drive unit 81 for rotating the magnetic recording medium 80, and a magnetic head 82 for recording / reproducing information on / from the magnetic recording medium 80.
A head drive section 83 for moving the magnetic head 82 relative to the magnetic recording medium 80, and a recording / reproducing signal processing system 84. The recording / reproducing signal processing system 84 can process the data input from the outside and send the recording signal to the magnetic head 82, or can process the reproducing signal from the magnetic head 82 and send the data to the outside. ing. Magnetic head 82 used in the magnetic recording / reproducing apparatus of the present invention
Is an MR (Magnetoresistence) that utilizes an anisotropic magnetoresistive effect (AMR) as a reproducing element.
It is possible to use a head suitable for higher recording density having not only an element but also a GMR element utilizing a giant magnetoresistive effect (GMR).

In the above magnetic recording / reproducing apparatus, when the magnetic layer contains a Co alloy, is separated into a large number of magnetic films by a layer containing CoRu bonds, and the magnetic films sandwiching at least one set of layers containing CoRu bonds are magnetized. Since a magnetic recording medium characterized by being magnetized in the same direction is used,
The second Co alloy layer can sufficiently maintain the crystal orientation and crystallinity, and the coercive forces Hc and S * do not decrease,
Further, compared with the case where a non-magnetic layer having a film thickness necessary for breaking magnetic coupling is provided, reproduction is performed without lowering the residual magnetization as compared with the case where the Co alloy layer has the same thickness. Since the output does not decrease, the SNR is improved, and the magnetic recording / reproducing apparatus is suitable for high recording density.

Next, an example of the manufacturing method of the present invention will be described.
As a non-magnetic substrate, an Al alloy (hereinafter also referred to as a NiP-plated Al substrate) on which a NiP plating film is formed, which is generally used as a substrate for a magnetic recording medium, or glass, ceramics, silicon, silicon carbide, carbon, resin Of non-metallic material or a substrate of these non-metallic materials on which a film of NiP or NiP alloy is formed is used.

The non-magnetic substrate has an average surface roughness Ra of 2 nm.
It is desirable that it is (20 Å) or less, preferably 1 nm or less.

The surface microwaviness (Wa) is 0.3.
It is preferably not more than nm (more preferably not more than 0.25 [nm]). Chamfer of chamfer part of the end face,
It is preferable for the flight stability of the magnetic head that at least one of the side surface portions has a surface average roughness Ra of 10 nm or less (more preferably 9.5 nm or less). The minute waviness (Wa) can be measured as a surface average roughness in a measurement range of 80 μm using, for example, a surface roughness measuring device P-12 (manufactured by KLM-TenCor).

If necessary, the surface of the non-magnetic substrate is textured, the substrate is washed, and the substrate is placed in the chamber of the film forming apparatus. If necessary, the substrate is heated to 100 to 400 ° C. by a heater, for example. On the non-magnetic substrate 1, a non-magnetic underlayer 2, a non-magnetic intermediate layer 3, a magnetic layer 4
Is formed by a DC or RF magnetron sputtering method using a sputtering target made of a material having the same composition as the material of each layer. The sputtering conditions for forming the film are as follows, for example. The inside of the chamber used for formation is evacuated until the degree of vacuum reaches 10 ⁻⁴ to 10 ⁻⁷ Pa. A substrate is housed in a chamber, Ar gas is introduced as a sputtering gas, and discharge is performed to perform sputter film formation. At this time, the power supplied is 0.2 to
A desired film thickness can be obtained by adjusting the discharge time and the supplied power to 2.0 kW.

When forming a non-magnetic underlayer, CrTi is used.
It is formed by a sputtering method using a sputtering target made of any one selected from the group-based alloys, CrW-based alloys, CrMo-based alloys, CrV-based alloys, CrSi-based alloys and Ni ₅₀ Al ₅₀ .

After forming the non-magnetic underlayer, 15 to 40n
A magnetic layer having a thickness of m is similarly formed by a sputtering method using a sputtering target made of the material of the magnetic layer. The sputtering target is CoC
rTa system, CoCrPt system, CoCrPtTa system, Co
CrPtB type, CoCrPtBTa type, CoCrPtB type
It is possible to use a material made of a material containing any one selected from Cu-based materials. For example, in the case of CoCrPt system, the content of Cr can be 10 to 25 at% and the content of Pt can be 8 to 16 at%. For example, Co
In the case of CrPtBTa system, the Cr content is 16 to 24a.
t%, Pt content is 8-16 at%, B content is 2
The content of Ta can be set to 8 at% and the content of Ta can be set to 1 to 4 at%. For example, in the case of CoCrPtBCu system, the Cr content is 16 to 24 at% and the Pt content is 8 to 16 a.
t content, B content is 2 to 8 at%, Cu content is 1 to
It can be 4 at%.

Here, the crystal orientation of Cr or Cr alloy of the non-magnetic underlayer is (200) when the NiP-plated aluminum alloy substrate is used, and the preferred orientation plane is N on the glass substrate.
When the iAl layer is provided, it is preferable to form it so that the preferentially oriented surface exhibits (112).

In the manufacturing method of the present invention, the magnetic layer is made of CoRu.
It is formed so as to be divided into a large number of magnetic films by a layer containing a bond and magnetized in the same direction when the magnetic films sandwiching at least one set of layers containing a CoRu bond are magnetized.

The layer containing CoRu coupling is 0.3 to 1.5 n in order to separate the magnetic coupling of the Co alloy magnetic film into upper and lower layers.
A thickness of m is preferred. If the CoRu couplings are arranged more neatly, the thickness is 0.3 nm, and if the thickness is at least less than this, the antiferromagnetic properties of the CoRu coupling do not work effectively. If it is greater than 1.5 nm, the antiferromagnetic layer is too thick. C below
This is because the o alloy magnetic film interferes with contributing to magnetic recording and reproduction. The film thickness of the layer containing CoRu bond means R
It means that the concentration of u is 30 at% or more.

Any of the following methods can be used to form a layer containing CoRu bonds. In order to form a layer containing CoRu bonds, after forming a Co alloy film, Ru is added thereon in an amount of 0.5 to 1 nm (preferably 0.6 nm).
It can be formed by stacking (.about.0.9 nm).

Alternatively, to form a layer containing CoRu bonds, a sputtering target using a material containing a composition having a Co content of 30 to 50 at% and a Ru content of 25 to 60 at% is used. It can be easily formed by using and sputtering. CoRu
It is preferable to form the film including the bond so that the film thickness is 0.8 to 2 nm.

After forming the Co alloy film, Co is continuously 0.1 to 0.3 nm (preferably 0.2 nm) and Ru is 0.5 to 1 nm (preferably 0.6 to 0.9 nm). Then, the CoRu bond can be formed efficiently. In the present specification, the "film thickness" in layers other than the layer containing CoRu bonds is obtained by multiplying the deposition rate (film thickness / hour) corresponding to the previously obtained sputtering conditions by the sputtering time.

After forming the Co alloy film, Co is 0.1 to 0.3 nm (preferably 0.2 nm), Ru is 0.5 to 1 nm (preferably 0.6 to 0.9 nm), C
When o is continuously laminated to 0.1 to 0.3 nm (preferably 0.2 nm), CoRu bond can be formed more efficiently.

However, if the layered Co is too thick at this time, the Co element diffuses into the Co alloy of the magnetic layer and may affect the composition of the Co alloy, so only one CoRu bond is arranged. The thickness, that is, the thickness of the Co film is preferably 0.2 to 0.3 nm. By doing so, when Ru is sputtered on the Co alloy, the formation ratio of CrRu bonds, PtRu bonds, and BRu bonds that do not contribute to antiferromagnetism other than CoRu bonds can be reduced.

When Ru is sputtered on the Co alloy, for example, the Co alloy is Co ₂₂ Cr ₁₂ Pt ₆ B (Cr content 22 at%, Pt content 12 at%, B content 6 a).
t%. 40% of the Co alloy already contains Cr, Pt, and B other than Co, and CoRu bonding can only be 60%. Furthermore, not all of them effectively form an antiferromagnetic layer, and if they are coupled side by side with, for example, Co-Ru-Ru-Co, they cancel each other's magnetization. Furthermore, if the CoRu couplings are arranged in a completely random direction, the antiferromagnetic layer does not function. Therefore, the thickness of Ru is calculated backward so that the thickness of the CoRu alloy layer is 6 to 10 Å (0.6 to 1 nm), and the deposition rate x time is calculated so that the thickness is the same. Is preferred. By doing so, when Ru is sputtered on the Co alloy, the formation ratio of CrRu bonds, PtRu bonds, and BRu bonds that do not contribute to antiferromagnetism other than CoRu bonds can be reduced.

When a nonmagnetic intermediate layer is provided between the nonmagnetic underlayer and the magnetic layer, a CoCr alloy (the content of Cr is 25
It is preferable to use a sputtering target with a raw material of about 45 at%). At this time, when the magnetic layer contains B, the Cr concentration in the region where the B concentration is 1 at% or more is 4 near the boundary between the non-magnetic underlayer and the magnetic layer.
It is preferable to form the film under the sputtering condition such that the content is 0 at% or less.

After forming the magnetic layer, a protective film, for example, a protective film containing carbon as a main component is formed by a known method such as a sputtering method, a plasma CVD method or a combination thereof.

Further, if necessary, a known lubricant such as a fluorine-based lubricant of perfluoropolyether is applied by a dipping method, a spin coating method or the like to form a lubricating layer.

When the orientation adjusting film is similarly formed between the nonmagnetic substrate 1 and the nonmagnetic underlayer 2, it is preferable to have a step of exposing the surface to an oxygen atmosphere. Exposing the surface to an oxygen atmosphere improves the crystal orientation of the Co alloy, which is preferable. The oxygen atmosphere to be exposed is, for example, 5 × 1
An atmosphere containing oxygen gas of 0 ⁻⁴ Pa or more is preferable. It is also possible to use a gas in which an atmospheric gas for exposure is brought into contact with water. The exposure time is preferably 0.5 to 15 seconds. For example, after the alignment adjusting film is formed, it can be taken out from the chamber and exposed to the outside air atmosphere or the oxygen atmosphere. Alternatively, a method of introducing the atmosphere or oxygen into the chamber to expose it without removing it from the chamber can be used. In particular, since the method of exposing in the chamber does not require a complicated step of taking out from the vacuum chamber, the nonmagnetic underlayer and the magnetic layer can be continuously processed as a series of film forming steps including film formation. preferable. In that case, for example, it is preferable that the ultimate vacuum is 10 ⁻⁶ Pa or less and the atmosphere contains oxygen gas of 5 × 10 ⁻⁴ Pa or more.

When an adhesion layer is formed between the non-magnetic substrate and the orientation adjustment film to improve the adhesion, a sputtering target having the same composition as the material of the adhesion layer is also formed before the orientation adjustment film is formed. Is used to form an adhesion layer having a film thickness of 1 to 100 nm by a sputtering method. As the sputtering target, a target made of any one selected from Cr, Ti and W can be used.

The magnetic recording medium manufactured according to the present invention comprises:
The magnetic layer contains a Co alloy, is separated into a large number of magnetic films by a layer containing CoRu bonds, and has at least one set of CoR layers.
It is characterized in that the magnetic films sandwiching the layer including u-coupling are magnetized in the same direction when magnetized or have no step in the magnetization curve and the Mrt value is 5 to 15% smaller than that of the magnetic recording medium having the same Co alloy film thickness. Since the magnetic recording medium is a magnetic recording medium, according to the manufacturing method of the present invention, magnetic characteristics such as coercive force are improved and recording and reproducing characteristics such as SNR are improved. Therefore, a magnetic recording medium suitable for high recording density can be easily manufactured. it can.

[0075]

EXAMPLES Hereinafter, the working effects of the present invention will be clarified by showing concrete examples. Example 1 A glass substrate having an outer diameter of 65 mm, an inner diameter of 20 mm, and a thickness of 0.635 mm was polished to an average surface roughness Ra of 0.3 nm, sufficiently washed with water, and then put into a sputtering machine. As the sputter machine, 3010 machine manufactured by Anerva Co. was used. The basic vacuum degree of the chamber was 9.0 × 10 ⁻⁶ Pa. The Ar pressure during film formation was 0.7 Pa. After heating the glass substrate up to 200 ° C. in the first chamber, a film made of NiAl as a non-magnetic underlayer having a thickness of 45 nm was formed by a sputtering method, and further Cr ₂₀ Mo (Mo content 2
0 at%. 15 nm in thickness was formed. Subsequently, a film made of Co ₃₅ Cr (Cr content 35 at%) was formed thereon to a thickness of 2 nm. Furthermore, subsequently, as a magnetic layer, Co ₂₂ Cr ₁₂ Pt ₆ B (Cr content ratio 22 at%, Pt content ratio 12 at%, B content ratio 6 a was formed by a sputtering method.
t%. 9 nm of a film made of a Co alloy having the composition
Next, a layer containing CoRu bonds was formed on the Co alloy by adding Ru.
It is formed by stacking 8 nm, and further Co ₂₂ Cr ₁₂ Pt
_A film of Co alloy having a composition of ₆ B was formed to a thickness of 9 nm. Then, a film having a thickness of 5 n is formed thereon by using a CVD method as a protective film.
After forming a carbon film of m, it was taken out from the sputtering machine. A lubricant (Zdol) was applied to the surface by the dip method.

The resulting magnetic recording medium was subjected to tape burnishing, and then a glide test was carried out using a burnish glide tester under the condition of a glide height of 0.4 μ inch, and the passed magnetic recording medium was tested by a write / read analyzer manufactured by Guzik. Reproduced signal output, PW50 (half-value width of solitary wave reproduction output), SNR, overwrite (O
Magnetic recording / reproducing characteristics such as W) were measured. Further, a composite type thin film magnetic recording head having a giant magnetoresistive (GMR) element was used for the measurement, and the recording condition was HF (high frequency condition) 170.
MHz, MF (medium frequency condition) 85 MHz, LF (low frequency condition) 28 MHz. Spindle speed is 72
The measurement radius was 00 rpm and the measurement radius was 23 mm. Thermal demagnetization is M
Measure the decrease of the playback signal output under F condition at 70 ° C and
Extrapolate the results measured after 10 seconds, 100 seconds, 1 second
Thermal demagnetization was calculated as the attenuation rate in 0 years.

The composition of the Co magnetic layer was analyzed by Auger spectroscopy, and the concentrations of Co and Ru in the portion containing CoRu bonds were quantitatively measured to confirm the film thickness. The static magnetic properties such as coercive force and S * were measured by VSM. The results are shown in Table 1.

Example 2 Instead of laminating 0.8 nm of Ru, 0.2 n of Co was used.
A magnetic recording medium was produced in the same manner as in Example 1 except that m and Ru were successively laminated to 0.8 nm.

Example 3 Instead of laminating 0.8 nm of Ru, 0.2 n of Co was used.
A magnetic recording medium was produced in the same manner as in Example 1 except that m, Ru was 0.8 nm and Co was 0.2 nm in this order.

Example 4 Instead of laminating 0.8 nm of Ru, Co ₃₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 30 at% was laminated to 1 nm.

Example 5 Instead of stacking 0.8 nm of Ru, Co ₄₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 40 at% was laminated to 1 nm.

Example 6 Instead of laminating 0.8 nm of Ru, Co ₅₀ Ru (Ru
A magnetic recording medium was prepared in the same manner as in Example 1 except that the content of 50 at% was laminated to 1 nm.

Example 7 Instead of laminating 0.8 nm of Ru, Co ₆₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 60 at% was laminated to 1 nm.

Example 8 Instead of laminating 0.8 nm of Ru, Co ₅₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 50 at% was laminated to 2 nm.

Example 9 Instead of stacking 0.8 nm of Ru, Co ₅₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 50 at% was laminated to 0.2 nm.

Comparative Example 1 A magnetic recording medium was prepared in the same manner as in Example 1 except that Ru was not laminated.

Comparative Example 2 A magnetic recording medium was produced in the same manner as in Example 1 except that Ru was not laminated and the thickness of the entire magnetic layer of Co ₂₂ Cr ₁₂ Pt ₆ B was set to 15 nm.

Comparative Example 3 Instead of laminating 0.8 nm of Ru, 0.2 nm of Ru was used.
A magnetic recording medium was produced in the same manner as in Example 1 except that the layers were laminated.

Comparative Example 4 A magnetic recording medium was prepared in the same manner as in Example 1 except that Ru was continuously laminated to 2 nm instead of 0.8 nm. Various measurements were performed on each of the finished magnetic recording media in the same manner as in Examples and Comparative Examples, and the results are shown in Table 1.

Example 10 Outer diameter 65 mm, inner diameter 20 mm, thickness 0.635 mm A
A film made of NiP is applied to the Mg alloy substrate by electroless plating.
To a mean surface roughness Ra.
Polish to 0.3 nm and wash thoroughly with water
Then, it was subjected to a texture treatment. Table after texture
The surface had an average surface roughness Ra of 0.3 nm. More than enough
After being washed and dried, it was put into a sputtering machine. Spa
As the tar machine, 3010 machine manufactured by Anerva Co. was used. Chamber
Has a basic vacuum of 9.0 × 10^-6It was Pa. During film formation
Ar pressure was 0.7 Pa. Substrate up to 220 ℃,
After heating in the first chamber, the
While applying a bias of 300 V as a magnetic underlayer, C
A film made of r with a thickness of 8 nm and further Cr₂₀Mo (including Mo
20at% of prevalence. 15 nm thick film of
It was Then Co on it ₃₅Cr (Cr content 35 at
%. 2) was formed to a thickness of 2 nm. Further on
As a magnetic layer by a sputtering method._{twenty two}Cr₁₂Pt
₆B (Cr content 22 at%, Pt content 12 at%,
B content 6 at%. ) Composition of a Co alloy film 7
nm, and then a layer containing CoRu bond is formed on the Co alloy.
Is formed by stacking 0.8 nm of Ru on the
_{twenty two}Cr₁₂Pt₆A film made of a Co alloy having a composition of B is 7 nm
Formed. Subsequently, a CVD method is used as a protective film on the above.
After forming a carbon film with a film thickness of 5 nm, sputter
I took it out of the machine. Lubricant (Zdol) was added to the surface.
It was applied by the dip method. Implement the completed magnetic recording medium
Various measurements were carried out in the same manner as in Example 1, and the results are shown in Table 1.

Example 11 Instead of laminating 0.8 nm of Ru, 0.2 n of Co was used.
A magnetic recording medium was produced in the same manner as in Example 10 except that m and Ru were continuously laminated to 0.8 nm.

Example 12 Instead of laminating 0.8 nm of Ru, 0.2 n of Co was used.
A magnetic recording medium was produced in the same manner as in Example 1 except that m, Ru was 0.8 nm and Co was 0.2 nm in this order.

Example 13 Instead of laminating 0.8 nm of Ru, Co ₃₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 30 at% was laminated to 1 nm.

Example 14 Instead of stacking 0.8 nm of Ru, Co ₄₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 40 at% was laminated to 1 nm.

Example 15 Instead of stacking 0.8 nm of Ru, Co ₅₀ Ru (Ru
A magnetic recording medium was prepared in the same manner as in Example 1 except that the content of 50 at% was laminated to 1 nm.

Example 16 Instead of laminating 0.8 nm of Ru, Co ₆₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 60 at% was laminated to 1 nm.

Example 17 Instead of stacking 0.8 nm of Ru, Co ₅₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 50 at% was laminated to 2 nm.

Example 18 Instead of laminating 0.8 nm of Ru, Co ₅₀ Ru (Ru
A magnetic recording medium was produced in the same manner as in Example 1 except that the content of 50 at% was laminated to 0.2 nm.

Comparative Example 5 A magnetic recording medium was prepared in the same manner as in Example 1 except that Ru was not laminated.

Comparative Example 6 A magnetic recording medium was prepared in the same manner as in Example 1 except that Ru was not laminated and the thickness of the entire magnetic layer of Co ₂₂ Cr ₁₂ Pt ₆ B was 12 nm.

Comparative Example 7 Instead of laminating 0.8 nm of Ru, 0.2 nm of Ru was used.
A magnetic recording medium was produced in the same manner as in Example 1 except that the layers were laminated.

Comparative Example 8 A magnetic recording medium was prepared in the same manner as in Example 1 except that Ru was continuously laminated to 2 nm instead of 0.8 nm. Various measurements were performed on each of the finished magnetic recording media in the same manner as in Examples and Comparative Examples, and the results are shown in Table 1.

[0103]

[Table 1]

Comparative Example 1 and Example 1, Comparative Example 5 and Example 1
Although 0 has the same thickness of the Co alloy layer, it means that Ru was not laminated or was laminated between the layers. The reproduction signal output (low frequency condition) is 16 in Comparative Example 1.
28, 1357 in Example 1, or 17 in Comparative Example 5.
04 and 1420 in Example 10. The Co alloy layer has the same film thickness, but
The layered structure of u has a layer of CoRu coupling showing antiferromagnetism, so that the reproduction signal output is small.

In Comparative Example 2, the thickness of the Co alloy was adjusted so that the same reproduction signal output (low frequency condition) as in Example 1 could be obtained. Example 1 in which the magnetic layer was cut by CoRu bonding
It can be seen that the SNR improved by 1.6 dB. Thermal demagnetization is within the preferable range of 2% / decade.

In Comparative Example 6, the thickness of the Co alloy was adjusted so that the same reproduction signal output (low frequency condition) as in Example 10 could be obtained. It can be seen that the SNR was improved by 1.7 dB in Example 10 in which the magnetic layer was cut by the CoRu bond.
Thermal demagnetization is within the preferable range of 2% / decade. In Comparative Example 3 and Comparative Example 7, the Ru concentration is less than 25%, which means that CoRu coupling is not sufficient to form an antiferromagnetic layer. Therefore, the SNR is not improved due to insufficient separation of the Co alloy magnetic layers.

In Comparative Example 4 and Comparative Example 8, the Co concentration was 10
%, Which means that the nonmagnetic layer is inserted. Therefore, Hc and S * are significantly reduced, and SNR is also insufficient.

[0108]

The magnetic recording medium of the present invention comprises at least
In a magnetic recording medium composed of a non-magnetic substrate, a non-magnetic underlayer, a magnetic layer and a protective film, the magnetic layer contains a Co alloy and Co
When a magnetic film that is separated into a large number of magnetic films by a layer containing Ru coupling and magnetizes at least one pair of layers containing CoRu coupling, magnetizes in the same direction or there is no step in the magnetization curve and the thickness of the Co alloy is Mr from the same magnetic recording medium
Since the magnetic recording medium is characterized in that the value of t is 5% to 15% smaller, thermal demagnetization due to thermal fluctuation is less likely to occur,
Since the SNR is improved, the magnetic recording medium is suitable for high recording density.

Further, the magnetic recording / reproducing apparatus of the present invention uses the above-mentioned magnetic recording medium, and thus is suitable for high recording density.

[Brief description of drawings]

FIG. 1 is a diagram showing directions of magnetization of a CoRu layer and a Co alloy layer of a magnetic recording medium of the present invention.

FIG. 2 is a diagram showing directions of magnetization of a CoRu layer and a Co alloy layer of a magnetic recording medium.

FIG. 3 is a diagram showing another direction of magnetization of a CoRu layer and a Co alloy layer of a magnetic recording medium.

FIG. 4 is a partial cross-sectional view showing an embodiment of a magnetic recording medium of the present invention.

FIG. 5 is a diagram of a magnetization curve of a magnetic recording medium (vertical axis: Mrt, unit is arbitrary; horizontal axis: external magnetic field (H) unit is [oe]).

FIG. 6 is a magnetization curve of the magnetic recording medium of the present invention (vertical axis: Mr.
t, unit is arbitrary. Horizontal axis: External magnetic field (H) unit is [o
e]).

FIG. 7 is a partial cross-sectional view showing another embodiment of the magnetic recording medium of the present invention.

FIG. 8 is a schematic configuration diagram showing an example of a magnetic recording / reproducing apparatus using the magnetic recording medium of the present invention.

[Explanation of symbols]

1: non-magnetic substrate, 2: non-magnetic underlayer, 3: non-magnetic intermediate layer, 4: magnetic layer, 5: protective film, 6: lubricating layer, 7: CoR
u-bond containing layer, 8: magnetic film, 9: orientation adjusting film, 10:
Adhesion layer 80: magnetic recording medium, 81: medium driving unit, 82: magnetic head, 83: head driving unit, 84: recording / reproducing signal processing system

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G11B 5/738 G11B 5/738 5/851 5/851 F term (reference) 5D006 BB01 BB07 BB08 CA06 CB04 CB06 CB08 5D112 AA05 BB05 BB06

Claims (12)

[Claims] 1. A non-magnetic substrate, a non-magnetic underlayer,
In a magnetic recording medium comprising a magnetic layer and a protective film, the magnetic layer contains a Co alloy, is separated into a large number of magnetic films by a layer containing CoRu bonds, and has at least one set of CoRu.
A magnetic recording medium characterized by being magnetized in the same direction when a magnetic film sandwiching a layer containing a bond is magnetized. 2. A non-magnetic substrate, a non-magnetic underlayer,
In a magnetic recording medium composed of a magnetic layer and a protective film, the magnetic layer contains a Co alloy, is separated into a large number of magnetic films by a layer containing CoRu bonds, and the magnetization curve has no step and is C
The value of Mrt is 5 to 5 from the magnetic recording medium having the same thickness of o alloy.
A magnetic recording medium characterized by being 15% smaller. 3. The thickness of the layer containing CoRu bonds is 0.3 to.
3. The magnetic recording medium according to claim 1, which has a thickness of 1.5 nm. 4. The content of Co in the layer containing CoRu bonds is 3
0 to 50 at% with Ru content of 25 to 60 at
%, Any one of claims 1 to 3 characterized in that
A magnetic recording medium according to item. 5. The magnetic according to claim 1, wherein the second magnetic film from the surface of the magnetic recording medium among the separated magnetic films has a thickness of 5 nm or more. recoding media. 6. The magnetic recording medium according to claim 1, wherein the total thickness of the magnetic layer is 25 nm or less. 7. A non-magnetic substrate is a glass substrate, a non-magnetic underlayer having a multilayer structure composed of a NiAl layer and a CrMo alloy layer, a non-magnetic intermediate layer composed of a CoCr alloy, and at least one set therein. 7. The magnetic recording medium according to claim 1, further comprising: a magnetic layer made of a CoCrPB-based alloy having a layer containing CoRu bond. 8. A non-magnetic substrate is Ni on the surface of an AlMg alloy substrate.
A substrate having a film made of P, comprising a Cr layer, Cr
Multi-layer non-magnetic underlayer made of Mo-based alloy, CoCr
7. A non-magnetic intermediate layer made of an alloy and a magnetic layer made of a CoCrPtB-based alloy having at least one set of layers containing CoRu bonds therein. 2. A magnetic recording medium according to item 1. 9. A layer containing CoRu bonds having a Co content of 3
0 to 50 at% with Ru content of 25 to 60 at
% Of at least one magnetic film formed by using a sputtering target using a material containing a composition of 10%, the magnetic layer being separated into a large number of magnetic films by a layer containing CoRu bonds, and sandwiching the layers containing CoRu bonds. A method of manufacturing a magnetic recording medium, which is formed so as to be magnetized in the same direction when magnetized. 10. A layer containing CoRu bonds is formed by forming a Co alloy film and then stacking 0.5 to 1 nm of Ru thereon, and a magnetic layer is composed of a layer containing CoRu bonds. A method of manufacturing a magnetic recording medium, which is formed so as to be magnetized in the same direction when at least one set of magnetic films sandwiching a layer containing CoRu coupling is magnetized. 11. A layer containing CoRu bonds is formed into a Co alloy film, and then Co is 0.1 to 0.3 nm and Ru is 0.1 to 0.3 nm.
It is formed by continuously laminating a magnetic layer having a thickness of 5 to 1 nm, the magnetic layer is separated into a large number of magnetic films by a layer containing CoRu bonds, and the same when at least one set of magnetic films sandwiching the layer containing CoRu bonds is magnetized. 1. A method of manufacturing a magnetic recording medium which is formed so as to be magnetized in a direction. 12. A magnetic recording / reproducing apparatus comprising a magnetic recording medium and a magnetic head for recording / reproducing information on / from the magnetic recording medium, wherein the magnetic recording medium is any one of claims 1 to 8.
A magnetic recording / reproducing apparatus, which is the magnetic recording medium according to the item 1.