JPH11219511A - Magnetic recording medium and magnetic recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an SN ratio, etc., better, recording and reproducing characteristic excellent, reliability high and high-density recording possible by successively laminating a ground surface layer having at least a B2 crystal structure and a Co alloy magnetic layer on a nonmagnetic substrate and forming a seed layer consisting essentially of Cr between the nonmagnetic substrate and the ground surface layer. SOLUTION: The seed layer consisting essentially of the Cr and the ground surface layer having the B2 crystal structure, such as NiAl, are successively formed on the nonmagnetic substrate and thereafter, the Co alloy magnetic layer is formed thereon. Further, the second ground surface layer consisting essentially of the Cr is preferably formed between the ground surface layer and the Co alloy magnetic layer. Namely, the seed layer essentially consisting of the Cr is disposed between the nonmagnetic substrate and the ground surface layer having the B2 crystal structure. The purpose thereof is to control the alignment of the crystal face of the ground surface layer formed on the seed layer, the second ground surface layer and eventually the Co alloy magnetic layer. As a result, the ratio of the axis of easy magnetization aligned within the substrate plane and a disk circumferential direction is greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention resides in a highly reliable magnetic recording medium having a high information recording density and excellent reproducing characteristics, and a magnetic recording apparatus used for a magnetic disk drive or the like.

[0002]

2. Description of the Related Art A disk-shaped magnetic recording medium (hereinafter, sometimes referred to as a "magnetic disk") often used in a recording apparatus is conventionally provided with a non-magnetic material such as NiP by electroless plating. A Cr or Cr alloy layer and a Co alloy magnetic layer are formed by a sputtering method on a non-magnetic substrate (hereinafter, sometimes simply referred to as a “substrate”) made of an Al—Mg alloy, and amorphous carbon or the like is mainly formed thereon. In general, a protective layer as a component, and further a lubricating layer and the like were formed.

[0003] At this time, concentric texturing is often performed on the surface of the NiP plating layer of the substrate, and as a method, concentric mechanical texturing is generally performed using diamond slurry or the like. This can improve the friction characteristics between the media and the head by giving a moderate surface roughness, and the crystal of the Cr layer is oriented in a specific direction along this concentric texturing structure. By doing so, the crystal structure of the Co alloy magnetic layer formed thereon is controlled, and as a result, the direction of the axis of easy magnetization of the magnetic thin film can be directed in the circumferential direction of the disk. Since the axis of easy magnetization is oriented in the circumferential direction of the disk, the recording and reproducing characteristics of the medium can be improved.

[0004] In recent years, from the viewpoints of impact resistance and surface smoothness, substrates of glass, especially crystallized glass, silicon, titanium, etc. have begun to be used instead of Al-Mg based alloy substrates. In these substrates, similar mechanical texturing can be performed after forming a metal film such as NiP on the substrate surface, and similar effects can be obtained in controlling the friction characteristics and the direction of the axis of easy magnetization. In the magnetic recording media, further higher recording density is required in the future, and therefore, further miniaturization of the magnetic particles in the magnetic layer is required. For example, Al-Mg alloys and glasses generally used in magnetic disks are used. C on non-magnetic substrate
Various proposals have been made to reduce the grain size in each layer, such as reducing the film thickness and lowering the temperature at the time of film formation, in order to reduce the particle size in the r or Cr alloy layer or the Co alloy magnetic layer such as the CoCrTaPt alloy. However, the demand for finer grain sizes corresponding to higher densities is progressing faster than these results.

In order to solve this problem and obtain more excellent magnetic properties, a technique has been developed in which an underlayer having a B2 crystal structure such as NiAl is used as a new underlayer. By using this technology, a high coercive force can be realized as compared to the case where a Cr underlayer is used, and a magnetic recording medium capable of high-density recording by making crystal grains of the magnetic layer fine can be realized. Obtainable. It has also been proposed to use an alloy layer having a B2 crystal structure below the Cr or Cr alloy layer (substrate side) (European Patent No. 0704839).

However, as a result of the study by the present inventors, Ni
Even when the Al underlayer is used for the substrate on which the above-mentioned concentric mechanical texturing has been performed, the phenomenon that the axis of easy magnetization is oriented in the circumferential direction of the disk is not observed, and a magnetic film having random magnetic characteristics almost in the disk surface. It has become. Further, although the alloy layer having the B2 crystal structure is effective in reducing the media grain size, the main crystal plane of the alloy layer is inclined and oriented with respect to the substrate surface, and as a result, The crystal plane of the provided Cr or Cr alloy layer is also oriented at an inclination with respect to the substrate surface by epitaxial growth, and the crystal plane of the main orientation component of the Co alloy magnetic layer further provided is also inclined with respect to the substrate surface, so that the axis of easy magnetization is formed. However, there is a disadvantage that it cannot be oriented in the substrate plane.

In general, a magnetic disk medium having a magnetic anisotropic orientation in the circumferential direction in the disk surface has a lower reproduction output especially at the time of high-density recording than a magnetic disk medium having no anisotropic orientation. It is known that it is small and has excellent recording / reproducing characteristics such as SN ratio and PW50. The recording / reproducing characteristics are very close to those of the directional medium. The reason for this is considered to be largely due to such an effect of making the magnetic film crystal grains fine. Therefore, if magnetic anisotropy in the circumferential direction within the substrate surface can be provided while utilizing the effect of miniaturizing the crystal grains of the underlayer having a B2 crystal structure such as NiAl, more excellent recording / reproducing characteristics can be obtained. It is expected that a magnetic disk medium will be obtained, but it has not been realized at present.

[0008]

SUMMARY OF THE INVENTION The present invention provides an underlayer having a B2 crystal structure such as NiAl as an underlayer on a non-magnetic substrate, preferably on a substrate having concentric mechanical texturing on its surface. In the magnetic recording medium used, as in the case where a Cr underlayer is used, the easy magnetization axis orientation in the substrate plane and in the disk circumferential direction is ensured, thereby improving the SN ratio and the like, and having excellent recording and reproducing characteristics. An object of the present invention is to provide an excellent magnetic recording medium and a magnetic recording device which are highly reliable and capable of high-density recording.

[0009]

SUMMARY OF THE INVENTION The present invention has been made as a result of intensive studies from this point of view. In this case, an underlayer having at least a B2 crystal structure and a Co alloy magnetic layer are sequentially laminated on a nonmagnetic substrate. Magnetic recording medium,
An object of the present invention is to provide a magnetic recording medium having a seed layer containing Cr as a main component between a nonmagnetic substrate and an underlayer, and a magnetic recording apparatus using the same.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The non-magnetic substrate of the magnetic recording medium of the present invention is, for example, an Al-M
Al alloy substrate such as g alloy, normal soda glass, aluminosilicate glass, amorphous glass, silicon,
Any non-magnetic substrate such as a substrate made of titanium, ceramics, and various resins can be used. Among them, it is preferable to use a glass substrate such as an Al alloy substrate or crystallized glass. In the process of manufacturing a magnetic disk, it is usual that the substrate is first washed and dried.
In the present invention as well, from the viewpoint of ensuring the adhesion of each layer, it is desirable to perform washing and drying before the formation.

In manufacturing the magnetic recording medium of the present invention,
It is preferable to form a nonmagnetic metal coating layer such as NiP on the surface of the nonmagnetic substrate. As a method for forming the nonmagnetic metal coating layer, a method used for forming a thin film such as an electroless plating method, a sputtering method, a vacuum evaporation method, and a CVD method can be used. In the case of a substrate made of a conductive material, it is possible to use electrolytic plating. The thickness of the nonmagnetic metal coating layer may be 50 nm or more. However, considering the productivity of the magnetic disk medium and the like, 50 nm or more 5
It is preferably not more than 00 nm. More preferably, it is 50 nm or more and 300 nm or less.

The area where the non-magnetic metal coating layer is formed is desirably the entire area of the substrate surface, but the present invention can be applied to only a part of the area, for example, only the area to be textured. Further, it is preferable to apply concentric texturing to the surface of the substrate or the surface of the substrate on which the nonmagnetic metal coating layer is formed. In the present invention, concentric texturing is, for example, mechanical texturing using loose abrasive grains and texture tape or texturing using a laser beam, or by using these together, by polishing in the circumferential direction. This refers to a state in which a large number of microgrooves are formed in the circumferential direction of the substrate.

[0013] As the type of free abrasive grains for mechanical texturing, diamond abrasive grains, particularly those whose surfaces are graphitized, are most preferred. Alumina abrasive grains are widely used as abrasive grains for mechanical texturing, but diamond abrasive grains have extremely good performance, especially from the viewpoint of orienting the axis of easy magnetization along the texturing grooves. Demonstrate.
Although the cause is not clear at present, extremely reproducible results have been obtained.

The surface of the substrate does not basically affect the effect of the present invention no matter what value the surface roughness (Ra) takes, but the fact that the head flying height is as small as possible is necessary for realizing high density magnetic recording. Is effective, and one of the features of these substrates is excellent surface smoothness.
a is preferably 2 nm or less, more preferably 1 nm or less, and particularly preferably 0.5 nm or less. However, the determination of Ra here is based on the case where measurement is performed using a stylus type surface roughness meter. At this time, the tip of the measuring needle has a radius of about 0.2 μm.

Next, on the non-magnetic substrate, a seed layer mainly composed of Cr and an underlayer having a B2 crystal structure such as NiAl are sequentially formed, and then a Co alloy magnetic layer is formed. Further, a second layer mainly composed of Cr is provided between the underlayer and the magnetic layer.
It is preferable to form the underlayer. A feature of the present invention resides in that a seed layer containing Cr as a main component is provided between a nonmagnetic substrate and an underlayer having a B2 crystal structure. The purpose is to form an underlayer having a B2 crystal structure formed on the seed layer,
The purpose of the present invention is to control the orientation of the crystal plane of the second underlayer containing Cr as a main component, and thus the Co alloy magnetic layer.

As a material having a B2 crystal structure, for example, CoAl, FeAl, NiAl, CoTi, FeTi
Binary alloys such as FeCoAl, CoNiAl, Ni
Ternary alloys such as FeAl and FeCoNiAl are exemplified. Incidentally, B2 crystal structure in the present invention, the systematic classification relates to a crystalline structure, including those that serial and L2 _0. The feature of this layer is that its grain size is small, its crystal lattice constant is about 2.88 °, and a second underlayer mainly composed of Cr (crystal lattice constant of 2. 88 ~
3.00%) or when a Co alloy magnetic layer is epitaxially grown, the particle size is preferably reduced. However, when an underlayer having a B2 crystal structure such as NiAl is directly provided on a substrate without forming a seed layer, (110) which is the main crystal plane of the underlayer is approximately 21 ° with respect to the substrate surface. For example, even if a second underlayer containing Cr as a main component is formed thereon, the main crystal plane Cr (11
0) is similarly strongly inclined at about 21 ° with respect to the substrate surface due to epitaxial growth. Accompanying this, Co (10
0) and the Co (101) crystal plane are also inclined at a high rate with respect to the substrate plane. As a result, about 20 ° to the substrate surface
In addition, an easy axis of magnetization having an inclination of about 54 ° appears at a high rate.

Further, when this underlayer is formed directly on the substrate subjected to the texturing as described above, and a Co alloy magnetic layer is formed thereon, that is, the layer structure of the present invention except for the particle layer is eliminated. In this case, the coercive force and other magnetostatic characteristics show excellent values, but magnetic anisotropy in the substrate surface hardly occurs, and the medium becomes an almost in-plane isotropic medium.

[0018] Such a problem such as the tilt orientation of the crystal plane is considered as follows.
The improvement was achieved by providing a seed layer mainly composed of Cr between the substrate and the underlayer having the B2 crystal structure.
That is, since the crystal plane of the seed layer mainly composed of Cr is oriented in parallel with the substrate surface, the underlying layer having a B2 crystal structure formed thereon has a main crystal plane whose main crystal surface is formed by epitaxial growth. Orient in parallel. Then, also in the second underlayer and the Co alloy magnetic layer formed on the underlayer, the proportion of crystal planes oriented parallel to the substrate surface is significantly increased, and the axis of easy magnetization is also oriented in the substrate surface. In addition, the seed layer is crystallographically oriented along the direction of the texturing groove, thereby controlling the crystal growth of the subsequently formed underlayer, and consequently producing the in-plane magnetism of the magnetic properties of the Co alloy magnetic layer. have. As the underlayer having the B2 crystal structure, CoAl, FeAl, NiA
1, FeCoAl, CoNiAl, NiFeAl, Fe
Al-containing alloys such as CoNiAl are preferable, and among them, those having an Al content of 30 to 70 atomic% (at%) are preferable, and 40 to 60 at%, particularly 45 to 55 at%.
% Is preferred. In addition, since the B2 crystal structure is important for miniaturization of the particle diameter of each layer, the B2 crystal structure is 70% or more, particularly 80% or more, especially 90% (both volume%) or more in the underlayer. Preferably it is.

In order to improve the matching of the crystal lattice constant with the adjacent layer such as the seed layer, the oxidation resistance, the spreadability, etc., the underlayer is made of Re, Nb, B, W, and Mo. ,
One or more elements such as Cr, V, Mn, Ta, Pd, and Hf may be added. The thickness of the underlayer having the B2 crystal structure may be appropriately determined depending on conditions of various characteristics required for the magnetic recording medium, but is usually 1 to 1500 nm.
Among them, 1 to 60 nm, particularly 1 to 30 nm is preferable.

As a material for the seed layer containing Cr as a main component, in addition to pure Cr, V, Ti, Mo, Zr, Hf, Ta, W, and G are used for the purpose of crystal matching with the Co layer.
e, Nb, Si, Cu, B and the like to which second and third elements are added, and Cr oxide are also included. Above all, pure Cr and T
Those having i, Mo, W, V, Ta, Si, Nb, Zr and Hf are preferable. The content of the second and third elements varies depending on the respective elements, but is generally 1 atomic% to 50 atomic%, preferably 5 atomic% to 30 atomic%, more preferably 5 atomic% to 20 atomic%. Atomic% range.

The film thickness of the seed layer containing Cr as a main component may be sufficient as long as it can express this anisotropy.
To 50 nm, preferably 0.3 to 30 nm, and more preferably 0.5 to 10 nm. Substrate heating may or may not be performed when forming a metal film containing Cr as a main component. The Co alloy magnetic layer is usually made of pure Co or CoN.
i, CoSm, CoCrTa, CoNiCr, CoCr
A Co alloy magnetic material generally used as a magnetic material such as Pt is used. In addition to these Co alloys, Ni, Cr,
An element such as Pt, Ta, W, B or a compound such as SiO ₂ may be added. For example, CoCrPtTa, CoC
rPtB, CoNiPt, CoNiCrPtB and the like. The thickness of the Co alloy magnetic layer is arbitrary, but usually 5
５０50 nm, preferably 10-30 nm.

Furthermore, it is preferable to further provide a second underlayer mainly composed of Cr between the underlayer having the B2 crystal structure and the Co alloy magnetic layer. This second underlayer can be made of the same material as the seed layer containing Cr as a main component, and the element composition of both may be the same or different. The thickness of the second underlayer can be arbitrarily set in accordance with the desired characteristics of the magnetic recording medium.
0 nm, preferably 5 to 50 nm.

Generally, an optional protective layer is formed on the magnetic layer, and then a lubricating layer is formed. As the protective layer,
Commonly used protective layer materials such as carbonaceous layers such as C, hydrogenated C, nitrogenated C, Amorphous C, and SiC, and SiO ₂ , Zr ₂ O ₃ , and TiN can be used. Further, the protective layer may be composed of two or more layers. The thickness of the protective layer is preferably 1 to 50 nm, particularly preferably 5 to 30 nm. Examples of the lubricant used for the lubricating layer include a fluorine-based lubricant, a hydrocarbon-based lubricant, a mixture thereof, and the like.
A lubricating layer is formed with a thickness of 4 nm.

The magnetic recording medium of the present invention further comprises a magnetic layer having a laminated structure of two or more kinds, and a non-magnetic CoC between a second underlayer mainly composed of Cr and the magnetic layer.
An intermediate layer such as r may be provided. The method for forming each layer of the magnetic recording medium is arbitrary, and examples thereof include physical vapor deposition methods such as direct current (magnetron) sputtering, high frequency (magnetron) sputtering, ECR sputtering, and vacuum deposition.

There are no particular restrictions on the conditions at the time of film formation, and the ultimate vacuum, substrate heating method and substrate temperature, sputtering gas pressure, bias voltage, etc. may be appropriately determined by the film forming apparatus. For example, in the case of sputtering film formation, usually, the ultimate vacuum degree is 1 × 10 ⁻⁶ Torr or less, the substrate temperature is from room temperature to 400 ° C., and the sputtering gas pressure is 1 × 1.
0 ^{−3 to} 20 × 10 ⁻³ Torr, and the bias voltage is generally 0 to −500V. In forming the film, a nonmagnetic substrate is generally used to promote the segregation of Cr in the magnetic layer.
It is preferable to heat to about 0 to 350 ° C. Substrate heating may be performed before the formation of the underlayer, or when a transparent substrate having a low heat absorption is used, in order to increase the heat absorption, a seed layer containing Cr as a main component or a B2 crystal structure is used. Is formed, and then the substrate is heated.
An alloy magnetic layer or a second underlayer containing Cr as a main component may be formed.

A magnetic recording apparatus according to the present invention comprises at least the magnetic recording medium described above, a driving unit for driving the magnetic recording medium in a recording direction, a magnetic head including a recording unit and a reproducing unit, and And a recording / reproducing signal processing means for performing signal input to the magnetic head and reproduction of an output signal from the magnetic head. By constructing the reproducing section of the above magnetic head with an MR head, it is possible to obtain sufficient signal strength even at high recording densities and realize a magnetic storage device with a high recording density of 2 gigabits per square inch or more. can do. If the magnetic head is levitated at a height of 0.01 μm or more and less than 0.05 μm, which is lower than the conventional height, the output is improved and a high S / N ratio can be obtained. Can be provided. The recording density can be further improved by combining a signal processing circuit based on the maximum likelihood decoding method.
A sufficient S / N can be obtained even when recording / reproducing at a recording density of TPI or more and a linear recording density of 200 kFCI or more and 2 Gbits / square inch or more.

Further, the reproducing portion of the magnetic head is disposed between a plurality of conductive magnetic layers which generate a large resistance change due to a relative change in their magnetization directions due to an external magnetic field, and the conductive magnetic layers. GM consisting of conductive non-magnetic layer
GMR using R head or spin valve effect
By using a head, the signal strength can be further increased, and more than 3 gigabits per square inch,
A highly reliable magnetic storage device having a linear recording density of kFCI or more can be realized.

[0028]

The present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist. Concentric mechanical texturing was performed on an Al—Mg alloy substrate (radius 95 mm) on which NiP plating had been performed, and a film was formed thereon using a DC sputtering method. At this time, the substrate surface roughness after mechanical texturing is Ra to 5 nm.
And

As a comparative example, a NiAl layer and a Co-
15Cr-2Ta-1W-6Pt (atomic%) alloy layer, C
Films were formed in the order of layers. Substrate temperature is 25
At 0 ° C., a substrate bias voltage of −200 V was applied to the substrate during the formation of Co-15Cr-2Ta-1W-6Pt. The Co-15Cr-2Ta-1W-6Pt film thickness was 17.5 nm. The thickness of the NiAl layer is 50 nm
During the film formation, a DC substrate bias potential was applied. The applied voltage at this time is 0, -100, -200, -300
V, and these are referred to as Comparative Examples 1 to 4, respectively.

On the other hand, using the same substrate and film forming apparatus as in Comparative Examples 1 to 4, a Cr layer, a NiAl layer, a Co-15Cr-2T
An a-1W-6Pt (atomic%) alloy layer and a C layer were sequentially formed to form a film. At this time, the thicknesses of the Cr layers were all set to 10 nm. In addition, Co-15Cr-2Ta-
The thickness of the 1W-6Pt film was 17.5 nm, and the thickness of the NiAl layer was 50 nm. Further, Co-15Cr-2Ta-
A DC bias potential was applied to the substrate when forming the 1W-6Pt alloy layer and the NiAl layer. The voltage value at this time is 0 V,-
The voltage was changed to 100 V, -200 V, and -300 V, and the respective values were used as Examples 1 to 4.

Table 1 below shows the magnetostatic characteristics of the magnetic recording medium thus prepared. Here, Br * t is the product of the residual magnetic flux density Br of the medium and the magnetic film thickness, and indicates the amount of residual magnetic flux per unit area of the medium. Hc is the radius of the medium 30 m
m is the in-plane coercive force measured in the circumferential direction of the medium surface at m. SQ is the saturation magnetization σs and the residual magnetization σr
SQ = σr / σs. S * is dσ / d
H = [sigma] r / {Hc (1-S *)}, which is called a coercive force squareness ratio. OR represents the coercivity ratio in the medium plane, and the coercivity in the circumferential direction of the medium is Hcci.
r, when the coercive force in the radial direction of the medium is Hcrad, OR =
Defined as Hccir / Hcrad. Generally, it is considered that the larger the OR, the better the recording / reproducing characteristics of the magnetic disk.

[0032]

[Table 1]

When the comparative examples 1 to 4 are compared with the examples 1 to 4, all of the ORs of the comparative examples have isotropic magnetic characteristics in the medium plane, whereas all of the ORs of the comparative examples have mechanical characteristics. It can be seen that the easy axis of magnetization is oriented along the groove direction of the formula texturing. Accordingly, the square non-SQ is also higher by about 0.1 in the embodiment. These are all factors that control the recording / reproducing characteristics of the magnetic recording medium, and the medium according to the present invention provided with the Cr seed layer formed on the lowermost layer of the medium showed superior characteristics.

Example 5 Example 1 except that the substrate surface roughness was changed to Ra to 1.2 nm.
Substrates similar to those in Nos. To 4 were prepared. This non-magnetic substrate is mounted in a front chamber of a DC magnetron sputtering apparatus, and evacuated. Simultaneously, the substrate is heated to 220 ° C., and after the vacuum pressure reaches 7 × 10 ⁻⁵ Torr or less, the vacuum pressure is reduced to 7 × 10 ⁻⁷ Torr. It was introduced into the following high vacuum film formation chamber, and a 5 nm thick Cr layer
A 60 nm CoAl alloy underlayer of 0Co-25Al was formed, and then the substrate temperature was increased to 270 ° C., and a 30 nm Cr underlayer (second underlayer) was formed thereon.

Subsequently, a bias voltage of -200 V is applied to the substrate to obtain 76Co-15Cr-6Pt-2.
A magnetic recording medium was formed by depositing a Ta-1W CoCrPtTaW (hereinafter abbreviated as Co alloy) magnetic layer to a thickness of 20 nm. From this magnetic recording medium, the area 2c
An mx 2 cm sample was cut out and analyzed for X-ray diffraction. The results will be described with reference to FIG. X-ray diffraction analysis
Both ordinary θ-2θ diffraction and low-angle incident diffraction at an incident angle of 1 ° with respect to the substrate surface were performed. In this analysis, a crystal plane oriented parallel to the substrate surface is detected by θ-2θ X-ray diffraction, and a crystal surface inclined with respect to the substrate surface is detected by low-angle incident X-ray diffraction.

FIG. 1A shows a spectrum of X-ray diffraction at θ-2θ, and FIG. 1B shows a spectrum of X-ray diffraction at low angle incidence. In FIG. 1a, in addition to the diffraction peak caused by the Al component of the Al—Mg alloy substrate, CoAl
(100), CoAl (200), Cr (200), C
o alloy (110) (referred to as Co (110) in the drawings, and the same applies hereinafter). It can be seen that the orientation of the crystal plane is very strong. On the other hand, in FIG. 1b, in addition to the background profile derived from the NiP plating layer on the substrate surface, only a few crystal planes having an orientation inclined with respect to the substrate surface are slightly detected. From the line diffraction spectrum, it can be seen that most of the easy axis of the magnetic layer is oriented in the substrate plane. Thereby, high recording density and improvement of the S / N ratio can be realized.

Comparative Example 5 A magnetic recording medium was prepared in the same manner as in Example 5 except that the Cr layer as a seed layer was not provided, and an X-ray diffraction sample was cut out and analyzed for X-ray diffraction. The result will be described with reference to FIG. FIG. 2a is a spectrum of X-ray diffraction of θ−2θ, FIG.
Shows the spectrum of X-ray diffraction at low angle incidence. FIG.
In a, the Co (100) crystal plane oriented parallel to the substrate surface is weakly detected. Further analysis revealed that CoAl (110) oriented parallel to the substrate surface,
Only a few Cr (110) crystal planes are formed. On the other hand, FIG.
b, CoAl (11) inclined at about 21 ° with respect to the substrate surface.
0), Cr (110) crystal plane is very strongly oriented. Correspondingly, about 19.
Co (100) which is oriented at an inclination of 5 ° and about 22.4 °,
The Co (101) crystal plane is also strongly oriented. From these two X-ray diffraction spectra, it can be seen that many of the easy axes of magnetization of the magnetic layer are inclined at about 20 ° and about 54 ° with respect to the substrate surface.

[0038]

According to the present invention, the ratio of the axis of easy magnetization oriented in the plane of the substrate and in the circumferential direction of the disk is remarkably improved as compared with the conventional magnetic recording medium, and the magnetic recording medium having a fine grain size is obtained. A medium is provided.

[Brief description of the drawings]

FIG. 1 shows (a) an X-ray diffraction spectrum of θ-2θ and (b) a low-angle incident X-ray diffraction spectrum of Example 5.

FIG. 2 shows (a) an X-ray diffraction spectrum of θ-2θ and (b) a low-angle incident X-ray diffraction spectrum of Comparative Example 5.

Claims (11)

[Claims] 1. A magnetic recording medium comprising: a base layer having at least a B2 crystal structure and a Co alloy magnetic layer sequentially laminated on a nonmagnetic substrate, wherein a magnetic recording medium is provided between the nonmagnetic substrate and the base layer having a B2 crystal structure. A magnetic recording medium comprising a seed layer mainly composed of Cr. 2. The magnetic recording medium according to claim 1, further comprising a second underlayer containing Cr as a main component between the underlayer having the B2 crystal structure and the Co alloy magnetic layer. 3. An underlayer having a B2 crystal structure is made of CoA.
1, FeAl, NiAl, CoTi, FeCoAl, C
3. The magnetic recording medium according to claim 1, comprising an alloy layer selected from the group consisting of oNiAl, NiFeAl, and FeCoNiAl. 4. A seed layer containing Cr as a main component is formed of a Cr or Cr—X alloy layer (X is Ti, Mo, W, V, Ta,
4. The magnetic recording medium according to claim 1, comprising one or more elements selected from the group consisting of Si, Nb, Zr, Hf and B). 5. The method according to claim 1, wherein the second underlayer mainly composed of Cr is C
r or Cr-X based alloy film (X is Ti, Mo, W, V,
The magnetic recording medium according to claim 2, wherein the magnetic recording medium comprises one or more elements selected from the group consisting of Ta, Si, Nb, Zr, Hf, and B). 6. The magnetic recording medium according to claim 1, wherein 70% or more of the underlayer having a B2 crystal structure has a B2 crystal structure. 7. The magnetic recording medium according to claim 1, wherein the non-magnetic substrate is a non-magnetic substrate having a non-magnetic coating layer. 8. The magnetic recording medium according to claim 1, wherein the non-magnetic substrate has a surface subjected to concentric texturing. 9. The magnetic recording medium according to claim 1, wherein the nonmagnetic substrate is a glass substrate. 10. The magnetic recording medium according to claim 1, wherein the medium is a magnetic disk. 11. A magnetic recording medium, a driving unit for driving the magnetic recording medium in a recording direction, a magnetic head including a recording unit and a reproducing unit, means for moving the magnetic head relative to the magnetic recording medium, 11. A magnetic storage device having a recording / reproduction signal processing means for inputting a recording signal to a head and outputting a reproduction signal from a magnetic head, wherein the magnetic recording medium is the magnetic recording medium according to claim 1. Magnetic recording device.