JPH0676260A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To produce the magnetic recording medium at a high yield and to improve the output and overwriting characteristic of magnetic recording thereof without degrading the squareness o a perpendicular magnetization curve by relieving the conditions for an oxygen partial, pressure at the time of film formation in order to obtain magnetic thin films having a high perpendicularly anisotropic magnetic field. CONSTITUTION:The magnetic layer 3 expressed by compsn. formula (CoaPtbBc)100-xOx ((a), (b), (c) and (x) are atomic % and a=100-b-c, 0<=b<=50, 0.1<=c<=30, 0<x<=15) is formed via an intermediate layer 2 on a nonmagnetic base 1. The intermediate layer 2 is formed of a face-centered cubic structure and the degree of orientation DELTAtheta50 determined by the locking curve of the (111) peak of the X-ray diffraction image of the intermediate layer 2 having the face-centered cubic structure is specified to <=10 deg. or the integrated intensity ratio I311/I222 of the (311) peak and (222) peak of the X-ray diffraction image is confined to <=0.8. More preferably, the intermediate layer 2 contains >=1 kinds among Al, Ni, Cu, Rh, Pd, Ag, Ir, Pt, Au, Fe and Co and a substrate contg. Ti or Cr between the nonmagnetic base 1 and the intermediate layer 2 is provided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a magnetic recording medium. More specifically, it relates to a perpendicular magnetic recording medium having a CoPtBO-based magnetic layer.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording, a perpendicular magnetic recording medium is being used in order to increase the recording density. As the magnetic thin film of this perpendicular magnetic recording medium,
Alloy magnetic thin films of CoCr, CoMo, CoV, CoRu, etc. are known.

Looking at the typical magnetic characteristics of the CoCr type alloys having the best magnetic characteristics among these alloys, the saturation magnetic flux density Bs is 0.4 to 0.6 T and the perpendicular coercive force Hcv is. , 1 when the substrate is heated to about 150 ° C. during deposition such as sputtering of this alloy thin film
Although the value reaches 20 kA / m, it shows a relatively low value of about 24 kA / m when the substrate temperature during film formation is about room temperature. Then, the squareness ratio in the vertical direction (Mr / M
s) is about 0.2, and the anisotropic magnetic field Hk is about 320 to 480k.
A / m. In this case, there is a problem that the saturation magnetic flux density Bs is relatively low, and since a high perpendicular coercive force Hcv cannot be obtained unless the substrate temperature during film formation is high, the substrate is inexpensive but heat resistant. There is a problem that a polyethylene terephthalate (PET) substrate having insufficient properties cannot be used.

On the other hand, the applicant of the present invention previously disclosed in Japanese Unexamined Patent Publication No.
In Japanese Patent No. 74012, a sufficient coercive force Hc is obtained even if the film thickness is increased, it is not necessary to raise the substrate temperature during film formation, and a sufficient saturation magnetic flux density Bs is easily realized.
An oPtBO-based alloy has been proposed. The composition formula of this CoPtBO-based alloy is (Co _a Pt _b B _c ) _100-x O _x.
, And its composition range is a = 100-b-
c, 0 ≦ b ≦ 50, 0.1 ≦ c ≦ 30, and 0 <x ≦ 1
5 (provided that a, b, c, and x are atomic%). In this magnetic film, the substrate temperature at the time of film formation is set to a relatively low temperature of about room temperature, and even if the film thickness is made relatively thick, a high perpendicular coercive force Hcv of about 240 kA / m,
High saturation magnetic flux density Bs (4πMs) of about 1 to 1.2T
And a high vertical anisotropic magnetic field Hk of about 1200 kA / m is realized.

Further, the applicant of the present invention previously disclosed in Japanese Unexamined Patent Publication No. 2-735.
In Japanese Patent Laid-Open No. 11-1999, even if the thickness of the magnetic thin film is increased by providing a thin film made of various materials such as Pt, Ti, Zr, and V on the underlayer of the magnetic thin film of CoPt-based or CoPtO-based alloy, It was proposed that a magnetic recording medium having excellent magnetic characteristics as a perpendicular magnetic recording medium or an in-plane magnetic recording medium can be manufactured without increasing the substrate temperature during film formation. Here, the perpendicular magnetic anisotropy field Hk (kA / m) and the saturation magnetic flux density Bs (T) of the perpendicular magnetic film made of a CoPtO alloy as the recording magnetic layer of the perpendicular magnetic recording medium have the following relationship. The one represented by the equation (1) is selected.

(10 ⁴ / 4π) × Hk ≧ Bs (1)

[0007]

However, when obtaining a perpendicular magnetization film using such a CoPtO-based alloy,
In practice, the various conditions during film formation, especially the oxygen partial pressure setting conditions, are strict, and these magnetic properties are sensitive to the oxygen content of the magnetic thin film, so it is difficult to control them, and the manufacturing process becomes complicated. There is a problem of becoming.

Further, in a magnetic recording medium having a perpendicularly magnetized film using a CoPtBO alloy, the coercive force tends to become excessively large in a composition region where the perpendicular anisotropy magnetic field is large, which deteriorates the overwrite characteristic. There was a problem of doing.

Further, generally in magnetic recording media, it is always desired to improve the output of magnetic recording without deteriorating the squareness of the perpendicular magnetization curve of the magnetic film.

The present invention is intended to solve the problems of the prior art as described above, and at the time of film formation for obtaining a magnetic thin film of CoPtBO type alloy having desirable magnetic characteristics, particularly a high perpendicular anisotropy magnetic field. It is a first object of the present invention to alleviate the oxygen partial pressure condition and to manufacture a desired magnetic recording medium with high reproducibility and yield. A second object of the present invention is to improve the overwrite characteristics of such a magnetic recording medium and the output of magnetic recording without deteriorating the squareness of the perpendicular magnetization curve.

[0011]

Means for Solving the Problems The present inventor achieves the above first object by providing an intermediate layer having a face-centered cubic structure between magnetic layers when they are formed on a non-magnetic substrate. It has been found that the above-mentioned second object can be achieved by further providing the soft magnetic layer between the magnetic layer and the intermediate layer, and has completed the present invention.

That is, the present invention provides the following compositional formula (Co _a Pt _b B _c ) _100-x O _x (wherein a, b, c and x are atomic% on a non-magnetic support, These are the following formulas: a = 100-bc; 0 ≦ b ≦ 50; 0.1 ≦ c ≦ 30; and 0 <x ≦ 15 are satisfied). A formed magnetic recording medium, wherein the intermediate layer has a face-centered cubic structure.

The present invention further provides a magnetic recording medium having a soft magnetic layer provided between the magnetic layer and the intermediate layer.

The present invention will be described in detail below.

As shown in FIG. 1, the basic embodiment of the magnetic recording medium of the present invention is such that a non-magnetic support 1 such as a glass substrate, an intermediate layer 2, and a magnetic layer 3 made of a CoPtBO type alloy are sequentially laminated. And is characterized in that the intermediate layer 2 has a face-centered cubic structure.

Thus, the above-mentioned Japanese Patent Laid-Open No. 2-74012
By forming the magnetic layer from the specific CoPtBO-based alloy proposed in Japanese Patent Laid-Open Publication No. 2003-242242 and further by forming the intermediate layer 2 into a face-centered cubic crystal structure, it is relatively thick without increasing the substrate temperature at the time of forming the magnetic layer. Even with the film thickness, a high vertical coercive force Hcv, a saturation magnetic flux density Bs (4πMs) and a vertical anisotropic magnetic field Hk can be realized.

In the present invention, when the face-centered cubic crystal of the intermediate layer 2 is the closest packed, the (111) plane of the crystal is parallel to the plane of the nonmagnetic support 1, that is, the (111) axis is nonmagnetic. It is perpendicular to the plane of the support 1. However, in reality, the (111) axes of all the crystals are not perpendicular to the plane of the non-magnetic support, and some of them tilt and fluctuate from the perpendicular direction. The degree of this fluctuation is determined when the intermediate layer 2 is examined by the surface analysis method using the θ-2θ scan in X-ray diffraction.
It can be represented by a range of angles at which the intensity is I / 2 or more with respect to the maximum intensity I in the rocking curve obtained by fixing 2θ on the (111) plane, ie, the orientation degree Δθ ₅₀ . When the value of the orientation degree Δθ ₅₀ is 0, it indicates that the crystal axes of the intermediate layer 2 are uniformly aligned, and conversely, the larger the value, the fluctuation in the direction perpendicular to the plane of the non-magnetic support 1. Is large, in other words, the crystal orientation is lowered.

Therefore, in the present invention, the orientation degree Δθ ₅₀ obtained from the rocking curve of the (111) peak of the X-ray diffraction image of the intermediate layer 2 having the face-centered cubic structure is expressed by the following equation (2) Δθ ₅₀ ≦ 10 (deg.) (2) It is preferable that the intermediate layer 2 be satisfied. In this way, Δθ _{50 is set} to 10 ° or less and the crystal orientation of the face-centered cubic crystal of the intermediate layer 2 is improved so that the magnetic characteristics of the magnetic layer 3, particularly the perpendicular anisotropy magnetic field Hk, can be improved as compared with the conventional one. It can be a high value, for example about 800 kA / m or more. Further, the range of oxygen partial pressure at the time of film formation for realizing the above-mentioned formula (1) (10 ⁴ / 4π) × Hk ≧ Bs (1), which is a condition to be satisfied as a perpendicular magnetization film, is set to be smaller than that of the conventional one. It can be significantly wider. This means that the oxygen partial pressure conditions during film formation can be relaxed, and therefore reproducibility and yield can be improved.

In the present invention, the degree of fluctuation of the face-centered cubic crystal of the intermediate layer 2 is controlled by the orientation degree Δθ ₅₀ as described above, and the integrated intensity I ₃₁₁ of the (311) peak of the X-ray diffraction image is used. The fluctuation of the crystal structure can also be controlled by the ratio (I ₃₁₁ / I ₂₂₂ ) of the integrated intensity I ₂₂₂ of the (222) peak. In this case, when the I ₃₁₁ / I ₂₂₂ ratio is 0, that is, when the (311) peak does not exist, the face-centered cubic crystals are ideally close-packed, and (111)
It shows that the axes are uniformly aligned in the direction perpendicular to the plane of the non-magnetic support 1, and that when the value of I ₃₁₁ / I ₂₂₂ increases, the orientation of the face-centered cubic crystal decreases. Shows.

In the present invention, the integrated intensity ratio I ₃₁₁ / I ₂₂₂ between the (311) peak and the (222) peak in the intermediate layer 2 is expressed by the following formula (3) I ₃₁₁ / I ₂₂₂ ≦ 0.8. It is preferable that the intermediate layer 2 satisfy the condition (3). I
_When the ratio of ₃₁₁ / I ₂₂₂ is 0.8 or less, the crystal orientation of the face-centered cubic crystal of the intermediate layer 2 is sufficiently good, which allows the magnetic properties of the magnetic layer 3, particularly the perpendicular anisotropy field. Hk
Can be set to a higher value than in the past, for example, a value of about 800 kA / m or more. Further, the range of oxygen partial pressure at the time of film formation for realizing the above-mentioned formula (1) (10 ⁴ / 4π) × Hk ≧ Bs (1), which is a condition to be satisfied as a perpendicular magnetization film, is set to be smaller than that of the conventional one. It can be significantly wider. This means that the oxygen partial pressure conditions during film formation can be relaxed, and therefore reproducibility and yield can be improved.

In the present invention, as the material for forming the intermediate layer 2, Al, Ni, C forming a face-centered cubic crystal are used.
u, Rh, Pd, Ag, Ir, Pt, Au, Fe and C
Those containing at least one kind of o are preferable, and in addition to them, Ti, Zr, V, Cr, Nb, Mo, Ta,
W, Hf, Mn, Re, Ru, Os, Zn, Cd, B,
Ga, Tl, C, Si, Ge, Sn, Pb, P, As,
Sb, Bi, S, Se, Te, Be, Mg, Ca, S
The intermediate layer 2 contains elements such as r, Ba, Sc, Y and rare earth elements.
Can be used within a range in which the face-centered cubic structure can be maintained, and these may be either a nonmagnetic film or a magnetic film.

Further, in the present invention, as shown in FIG. 2, an underlayer 4 containing at least Ti or Cr is further formed between the non-magnetic support 1 and the intermediate layer 2 to form the intermediate layer 2. The crystal orientation of the face-centered cubic structure is further improved, and the perpendicular coercive force Hcv and the saturation magnetic flux density Bs of the magnetic layer 3 are improved.
The magnetic characteristics such as (4πMs) and the perpendicular anisotropy magnetic field Hk can be improved. In particular, when the intermediate layer 3 is made of a non-magnetic film such as AlCu which is slightly inferior in crystal orientation to an expensive non-magnetic metal film such as Pt, Au or Pd which has excellent crystal orientation. However, an effect equivalent to that of an expensive metal such as Pt can be obtained, and in this case, there is an advantage that the intermediate layer 2 can be formed at low cost without using an expensive metal.

In the perpendicular magnetic recording, a single pole head may be used as the magnetic head and a ring head may be used. Particularly, in the case of the single pole head, the magnetic poles of 0. It has been proposed to use a relatively thick soft magnetic layer of about 5 to 1.0 μm (Suzuki, Negiya, Yoshida and Kitakami, IEICE Technical Report, MR88-6 (198).
8)), when a relatively thick soft magnetic layer having a face-centered cubic structure is used as the intermediate layer 2 in the present invention,
The presence of the underlayer 4 containing at least Ti or Cr is
Not only is the crystal orientation of the intermediate layer 2 improved, but
There is an advantage that the adhesion strength of the intermediate layer 2 can be improved and the crystallinity and orientation of the magnetic layer 3 can be improved.

The thickness of such an underlayer 4 can be appropriately determined according to need, but if it is too thick, the crystal orientation of the intermediate layer 2 formed thereon may be deteriorated, so that it is generally used. The thickness may be about 5 nm to about 50 nm. The base layer 4 may contain other metal elements or the like other than Ti or Cr as long as the crystal orientation of the intermediate layer 2 is not adversely affected.

In the present invention, as shown in FIGS. 3 and 4, a soft magnetic layer 5 may be further provided between the intermediate layer 2 and the magnetic layer 3. By further providing the soft magnetic layer 5 in this manner, the output of magnetic recording and the overwrite characteristic of the magnetic recording medium can be improved without deteriorating the squareness of the perpendicular magnetization curve.

Such soft magnetic layer 5 preferably has a body-centered cubic structure or a face-centered cubic structure. This is because when the structure of the soft magnetic layer 5 is an amorphous structure, the crystal orientation of the magnetic layer 3 is not sufficiently improved, and therefore the recording / reproducing characteristics particularly in the short wavelength region may not be sufficiently improved. Is. A FeSi layer can be preferably exemplified as the soft magnetic layer 5 having such a body-centered cubic structure or a face-centered cubic structure.

By forming the intermediate layer 2 from a soft magnetic film, the intermediate layer 2 can also serve as the soft magnetic layer 5.

In the present invention, the material of the non-magnetic support 1, its shape and thickness, and the thickness of the intermediate layer 2 can be appropriately determined as required. If necessary, as shown in FIGS. 2 and 4, a protective layer 6 made of carbon or the like may be formed on the magnetic layer 3.

In the magnetic recording medium of the present invention, for example, an intermediate layer made of Pt, AlCu, or the like is laminated on a non-magnetic support such as a glass substrate by sputtering, and the target and inflowing gas are changed, and the magnetic layer is formed by sputtering. It can be manufactured by stacking. If necessary, before laminating the magnetic layer, the soft magnetic layer can be laminated by sputtering while changing the target and the inflowing gas.
Further, the carbon protective film can be formed after laminating the magnetic layers. It is also possible to previously form an underlayer made of Ti or the like on the nonmagnetic support by sputtering before stacking the intermediate layer.

[0030]

In the magnetic recording medium of the present invention, since the intermediate layer provided between the non-magnetic support and the magnetic layer has a face-centered cubic crystal structure, it is possible to increase the substrate temperature during film formation of the magnetic layer. Further, even if the film thickness of the magnetic layer is made relatively thick, it is possible to realize a high perpendicular coercive force Hcv, a saturation magnetic flux density Bs (4πMs) and a perpendicular anisotropic magnetic field Hk. In particular, when controlling the degree of crystal orientation of the face-centered cubic structure of the intermediate layer, the degree of orientation Δθ ₅₀ obtained by the rocking curve of the (111) peak of the X-ray diffraction image of the intermediate layer is set to 10 ° or less. Or, the integrated intensity I ₃₁₁ of the (311) peak and (2
22) Ratio of integrated intensity I _{222 of} peak (I ₃₁₁ / I
_By setting ₂₂₂ ) to 0.8 or less, the crystal orientation can be well controlled.

If an underlayer containing at least Ti or Cr is formed between the non-magnetic support and the intermediate layer, the crystal orientation of the intermediate layer can be further improved, and the magnetic properties of the magnetic layer can be improved. It is possible to improve the characteristics.

When the soft magnetic layer is provided between the magnetic layer and the intermediate layer, the overwrite characteristic and the output of magnetic recording can be improved without deteriorating the squareness of the perpendicular magnetization curve. .

[0033]

EXAMPLES The magnetic recording medium of the present invention will be specifically described below with reference to examples. In the following examples and comparative examples, the perpendicular anisotropy magnetic field Hk was measured with a sample vibrating magnetometer, and Cu- was used for evaluating the crystallinity of the magnetic layer and the like.
The X-ray diffraction image was analyzed using Kα ray. Further, for evaluation of magnetic properties, a Kerr loop tracer (applied magnetic field of 960 kA / m) was used. In the case of evaluating the recording / reproducing characteristics, a carbon protective film is laminated on the surface of the magnetic film by a sputtering method to a thickness of 10 nm, and then a liquid lubricant is applied to manufacture a magnetic disk. -In-gap head (track width 2) using FeRuGaSi alloy film with saturated magnetic flux density
5 μm, gap length 0.35 μm), and the peripheral speed is 3
Recording / reproduction was performed under the condition of m / sec for evaluation.

Example 1 A Pt intermediate layer and a magnetic layer were sequentially laminated on a non-magnetic support made of a slide glass substrate by a magnetron type sputtering apparatus to manufacture a magnetic recording medium as shown in FIG. The film forming conditions for the intermediate layer and the magnetic layer at this time are as follows.

Background vacuum degree: 1.3 × 10 ⁻⁴ Pa Nonmagnetic support temperature: Room temperature Sputter input power: 300 W Sputter gas total pressure: 2.0 Pa Magnetic layer gas composition: Ar and oxygen total gas flow rate: 50 SCCM oxygen Partial pressure: 0.035 Pa Target: Alloy of Co ₆₈ Pt ₂₃ B ₉ (atomic%) composition (diameter 10 cm × thickness 4 mm) Film thickness: 100 nm Intermediate layer Introduced gas: Ar gas Target: Pt Under the above conditions The magnetic recording medium having various (111) peak orientation degrees Δθ ₅₀ of Pt intermediate layers was manufactured by changing the Ar gas flow rate, gas pressure, and intermediate layer thickness when forming the intermediate layer. take-ray diffraction image, Pt middle layer 2 (111) perpendicular anisotropy magnetic field and the orientation [Delta] [theta] ₅₀ as determined by the rocking curve of the peak H of this time
I investigated the relationship with. The result is shown in FIG.

The integrated intensity ratio I ₃₁₁ / I of the (311) peak and the (222) peak of the X-ray diffraction image of the intermediate layer
The relationship between ₂₂₂ and the perpendicular anisotropy magnetic field Hk was investigated. The result is shown in FIG.

Example 2 A magnetic recording medium was manufactured by repeating Example 1 except that Au was used as the intermediate layer.
The relationship between the orientation degree Δθ ₅₀ obtained from the rocking curve of the (111) peak in (1) and the perpendicular anisotropy magnetic field Hk was investigated.
The result is shown in FIG.

Also, the integrated intensity ratio I ₃₁₁ / I of the (311) peak and the (222) peak of the X-ray diffraction image of the intermediate layer.
The relationship between ₂₂₂ and the perpendicular anisotropy magnetic field Hk was investigated. The result is shown in FIG.

Example 3 A magnetic recording medium was manufactured by repeating Example 1 except that Pd was used as the intermediate layer.
The relationship between the orientation degree Δθ ₅₀ obtained from the rocking curve of the (111) peak in (1) and the perpendicular anisotropy magnetic field Hk was investigated.
The result is shown in FIG.

Further, the integrated intensity ratio I ₃₁₁ / I of the (311) peak and the (222) peak of the X-ray diffraction image of the intermediate layer.
The relationship between ₂₂₂ and the perpendicular anisotropy magnetic field Hk was investigated. The result is shown in FIG.

Example 4 A magnetic recording medium was manufactured by repeating Example 1 except that the intermediate layer was replaced with Ag.
The relationship between the orientation degree Δθ ₅₀ obtained by the rocking curve of the (111) peak of γ and the perpendicular anisotropy magnetic field Hk was investigated.
The result is shown in FIG.

Also, the integrated intensity ratio I ₃₁₁ / I of the (311) peak and the (222) peak of the X-ray diffraction image of the intermediate layer.
The relationship between ₂₂₂ and the perpendicular anisotropy magnetic field Hk was investigated. The result is shown in FIG.

As is clear from FIG. 5, the perpendicular anisotropy magnetic field Hk of the magnetic layer has a strong correlation with the orientation degree Δθ ₅₀ of the intermediate layer, and shows a steep slope in the vicinity of Δθ ₅₀ = 10 °. , And 800 kA / m in the range of Δθ ₅₀ ≦ 10 °
The above perpendicular anisotropy magnetic field Hk was obtained.

By the way, the saturation magnetic flux density Bs of the magnetic layers obtained in Examples 1 to 4 is about 1 to 1.2T, and the above-mentioned formula (1) (10 ⁴ / 4π) for obtaining a good perpendicular magnetization film is obtained. ) × Hk ≧ Bs (1) Substituting the numerical value (1 to 1.2T) of the saturation magnetic flux density Bs, the perpendicularly anisotropic magnetic field Hk required for practical use is about 800.
It becomes kA / m or more. Therefore, in Examples 1 to 4, it was found that by setting the orientation degree to Δθ ₅₀ ≦ 10 °, the formula (1) was satisfied, and good perpendicular magnetic recording media were obtained.

Further, as is apparent from FIG. 6, the perpendicular anisotropic magnetic field Hk of the magnetic layer depends on the integrated intensity ratio I ₃₁₁ / I ₂₂₂ of the (311) peak and the (222) peak of the intermediate layer, If this ratio is less than 0.8, 800 kA /
A perpendicular anisotropic magnetic field Hk of m or more is obtained. Therefore,
It can be seen that a good perpendicular magnetic recording medium can be obtained by setting the integrated intensity ratio I ₃₁₁ / I ₂₂₂ to 0.8 or less.

For reference, FIG. 7 shows an example of an X-ray diffraction image in the case of the Au intermediate layer. In this figure, ASTM generally used as a standard for X-ray diffraction data
(Amerian Society for Test
The position of the diffraction peak of Au having a face-centered cubic (fcc) structure is shown based on the Ining Materials card. Further, P _Co indicates the peak of the magnetic layer (CoPtBO), and P ₁₁₁ , P ₃₁₁ and P ₂₂₂ indicate the (111) peak, (311) peak and (222) peak of the Au intermediate layer, respectively. X-ray diffraction images similar to those in FIG. 7 can be obtained for other face-centered cubic crystal intermediate layers.

FIG. 8 shows the relationship between the peak intensity of the P _Co peak and the integrated intensity ratio I ₃₁₁ / I ₂₂₂ . As is clear from this figure, the smaller the integrated intensity ratio I ₃₁₁ / I _{222, the} stronger the peak intensity of P _Co. This indicates that the crystallinity of the magnetic layer is improved. The reason is that the smaller the integrated intensity ratio I ₃₁₁ / I ₂₂₂ is, the direction of the (111) axis is oriented more perpendicularly to the plane of the non-magnetic support, and the orientation improves the crystallinity of the magnetic layer. It is thought that

Example 5 A Pt intermediate layer and a magnetic layer were sequentially laminated on a non-magnetic support made of a slide glass substrate by a magnetron type sputtering apparatus to manufacture a magnetic recording medium as shown in FIG. The film forming conditions are the same as in Example 1 except that the intermediate layer is formed under the following conditions.

Intermediate layer Introduced gas: Ar gas Gas flow rate: 50 SCCM Total sputtering pressure: 2.0 Pa Target: Pt film thickness: 100 nm (Intermediate layer orientation degree Δθ ₅₀ = 7.0 to 8.0 (de)
g. ), The integrated intensity ratio I _{31 1} / I ₂₂₂ = 0.02-
0.04) In this case, under the above conditions, various magnetic layers were formed by changing the oxygen partial pressure at the time of forming the magnetic layer to produce various magnetic recording media. The relationship between the perpendicular magnetic anisotropy magnetic field Hk and the oxygen partial pressure was investigated for these. The result is shown in FIG.

Example 6 A magnetic recording medium was manufactured by repeating Example 5 except that the intermediate layer was replaced with Au, and the relationship between the perpendicular magnetic anisotropy magnetic field Hk and the oxygen partial pressure was examined in the same manner as in Example 5. It was The result is shown in FIG. The degree of orientation Δθ ₅₀ of the Au intermediate layer was 6.8 to 8.0 (deg.). Also, the integrated intensity ratio _I 311 _{/ I 222} was 0.04 to 0.07.

Example 7 A magnetic recording medium was manufactured by repeating Example 5 except that Pd was used as the intermediate layer, and the relationship between the perpendicular magnetic anisotropy magnetic field Hk and the oxygen partial pressure was examined in the same manner as in Example 5. It was The result is shown in FIG. The degree of orientation Δθ ₅₀ of the Pd intermediate layer was 8.0 to 9.0 (deg.). Further, the integrated intensity ratio I ₃₁₁ / I ₂₂₂ was 0.3 to 0.5.

Example 8 A magnetic recording medium was manufactured by repeating Example 5 except that the intermediate layer was replaced with Ag, and the relationship between the perpendicular magnetic anisotropy magnetic field Hk and the oxygen partial pressure was examined in the same manner as in Example 5. It was The result is shown in FIG. The degree of orientation Δθ ₅₀ of the Pd intermediate layer was 8.0 to 9.0 (deg.). Further, the integrated intensity ratio I ₃₁₁ / I ₂₂₂ was 0.1 to 0.35.

Comparative Example 1 A magnetic recording medium having a magnetic layer laminated directly on a non-magnetic support was manufactured by repeating Example 5 except that no intermediate layer was provided. The relationship between the anisotropic magnetic field Hk and the oxygen partial pressure was investigated. The results are shown in Fig. 9.
In FIG. 9, the solid line a is the result of Examples 5 to 8 and the dotted line b is the result of Comparative Example 1.

As is apparent from FIG. 9, in the measured total oxygen partial pressure range (0 to 0.07 Pa), Examples 5 to 8 were performed.
It is understood that the perpendicular anisotropy magnetic field Hk of the magnetic layer of No. 2 is larger than the perpendicular anisotropy magnetic field Hk of the magnetic layer of Comparative Example 1.

By the way, the saturation magnetic flux density Bs of the magnetic layers obtained in Examples 5 to 8 is about 1 to 1.2T, and the above-mentioned formula (1) (10 ⁴ / 4π) for obtaining a good perpendicular magnetization film is obtained. ) × Hk ≧ Bs (1) Substituting the numerical value (1 to 1.2T) of the saturation magnetic flux density Bs, the perpendicularly anisotropic magnetic field Hk required for practical use is about 800.
It becomes kA / m or more. The range of the oxygen partial pressure for obtaining such a perpendicular magnetization film is 0.035 P in Comparative Example 1.
In the vicinity of a, only in the fifth and sixth embodiments, namely Pt.
In the case of the magnetic recording medium having the Au and Au intermediate layers, the oxygen partial pressure is in the range of about 0.02 Pa to 0.06 Pa, and in the case of the magnetic recording medium having the Pd and Ag intermediate layers of Examples 7 and 8. Has an oxygen partial pressure of approximately 0.03 Pa to 0.0
The range is 5 Pa. Therefore, according to the example, it is understood that the oxygen partial pressure condition during film formation can be relaxed.

Example 9 An Au intermediate layer and a magnetic layer were sequentially laminated on a non-magnetic support made of a slide glass substrate by a magnetron type sputtering apparatus to manufacture a magnetic recording medium as shown in FIG. Further, a carbon protective film having a thickness of 10 nm was formed on the surface of the magnetic layer by a sputtering method. At this time, the film formation conditions for the intermediate layer and the magnetic layer were set so that the background vacuum degree was 5 × 10 5.
And ^{-5 Pa,} except that the film thickness of the magnetic layer and 200 nm, the intermediate layer is the same as the film formation conditions of Example 6, the magnetic layer is the same as the film formation conditions of Example 1.

Example 10 An Au intermediate layer, a soft magnetic layer, a magnetic layer, and a carbon protective film were sequentially laminated on a non-magnetic support made of a slide glass substrate by a magnetron type sputtering device, and magnetic recording as shown in FIG. The media was manufactured. The film forming conditions for the intermediate layer and the magnetic layer at this time are the same as in Example 9, and the film forming conditions for the soft magnetic layer are Fe in place of Au as a target in the film forming conditions for the intermediate layer in Example 9. _The conditions for forming the intermediate layer are the same, except that an alloy having a composition of ₉₆ Si ₄ (atomic%) is used and the thickness thereof is set to 15 nm.

Regarding the magnetic recording media obtained in Examples 9 and 10, the measurement results of the recording density characteristics are shown in FIG. 10, and the measurement results of the perpendicular magnetization curve are shown in FIG.
Shown in (a) and (b).

As is apparent from FIG. 10, the magnetic recording medium of Example 9 has practically sufficient output characteristics for magnetic recording, but the recording medium of Example 10 further provided with a soft magnetic layer has a long length. In the wavelength region (for example, 12 μm) to the short wavelength region (for example, 0.25 μm), the output of the magnetic recording of several dB can be improved as compared with the magnetic recording medium of Example 9.

As is clear from FIG. 11, the magnetic recording medium of the present invention retains high squareness.

Further, the overwrite characteristics of the magnetic recording media of Examples 9 and 10 were evaluated by the reduction amount of the recorded information at the recording wavelength of 6 μm when the recording was performed at the recording wavelength of 6 μm and then overwritten at the recording wavelength of 1 μm. did. The results are shown in Table 1. In this case, the smaller the value, the better the overwrite characteristic.

[0062]

[Table 1] Overwrite characteristics [recording wavelength 1 μm / 6 μm] (dB) Example 9-28.6 Example 10-44.0 As is clear from Table 1, the overwrite characteristics of the magnetic recording medium of Example 9 are practically sufficient, but the recording medium of Example 10 further provided with a soft magnetic layer was the magnetic recording medium of Example 9. It was observed that the overwrite characteristic was improved by 15.4 dB as compared with the recording medium.

Further, the X-ray diffraction intensity [cps] and the degree of orientation Δθ ₅₀ of the soft magnetic layers and magnetic layers of Examples 9 and 10 were obtained.
Are shown in Table 2. In this case, the larger the value of the X-ray diffraction intensity, the better the crystallinity.

[0064]

[Table 2] Magnetic film (002) peak Soft magnetic layer (110) peak Diffraction intensity Δθ ₅₀ Diffraction intensity Δθ ₅₀ [cps] [deg. ] [Cps] [deg. Example 9 123k 4.8 --- --- As apparent from Example 10 96k 6.3 8.1k 3.7 Table 2, the crystallinity of the magnetic film of the magnetic recording media of Examples 9 and 10 And the orientation was practically sufficient. For reference, as the soft magnetic layer, Nb ₁₁ Zr ₄ Ta is used.
_A magnetic recording medium was manufactured by repeating Example 10 except that ₂ amorphous alloy layers were used, and X-rays of the soft magnetic layer and the magnetic layer of the obtained magnetic recording medium were obtained in the same manner as in Examples 9 and 10. The diffraction intensity and the degree of orientation Δθ ₅₀ were measured. As a result, the crystallinity and orientation of the magnetic layer were lower than those of Examples 9 and 10.

Example 11 On a non-magnetic support made of a slide glass substrate, a Ti underlayer and Ni were formed by a magnetron type sputtering device.
CuTa intermediate layers were sequentially laminated. The film forming conditions of the underlayer and the intermediate layer at this time are as follows.

Background vacuum degree: 1.3 × 10 ⁻⁴ Pa Nonmagnetic support temperature: Room temperature Sputtering power: DC300W Intermediate layer Introduced gas: Ar gas Total gas flow rate: 100 SCCM Film thickness: 200 nm Target: Ni ₄₅ Cu ₅₀ Ta
Alloy of ₅ (atomic%) composition (diameter 10 cm × thickness 4 mm) Underlayer Introduced gas: Ar gas Total gas flow rate: 100 SCCM target: Ti X-ray diffraction image was obtained by changing the underlayer thickness under the above conditions. Then, the dependency of the orientation degree Δθ _{50 on} the Ti underlayer thickness on the (111) peak intensity and the rocking curve of the (111) peak of the NiCuTa intermediate layer having the face-centered cubic structure at this time was examined. The results are shown in FIGS. 12 and 13.

Example 12 Example 11 was repeated except that Cu was used for the intermediate layer, and the thickness of the underlayer was changed in the same manner as in Example 11 to obtain X.
A line diffraction image was taken, and the dependency of the (111) peak intensity and the orientation degree Δθ ₅₀ of the (111) peak of the Cu intermediate layer on the Ti underlayer thickness was examined. The results are shown in FIGS. 12 and 13.

Example 13 Example 11 was repeated except that Ni was used for the intermediate layer, and the thickness of the underlayer was changed in the same manner as in Example 11 to obtain X.
A line diffraction image was taken to examine the dependency of the (111) peak intensity and the (111) peak orientation degree Δθ ₅₀ of the Ni intermediate layer on the thickness of the Ti underlayer. The results are shown in FIGS. 12 and 13.

Example 14 Example 11 was repeated except that Al was used for the intermediate layer, and the thickness of the underlayer was changed in the same manner as in Example 11 to obtain X.
A line diffraction image was taken, and the dependency of the (111) peak intensity and the orientation degree Δθ ₅₀ of the (111) peak of the Al intermediate layer on the thickness of the Ti underlayer was examined. The results are shown in FIGS. 12 and 13.

Example 15 Example 11 was repeated except that Cu ₈₀ Al ₂₀ (atomic%) was used for the intermediate layer in Example 11, and the thickness of the underlayer was changed in the same manner to obtain an X-ray diffraction image. At this time, the dependence of the (111) peak intensity and the (111) peak orientation degree Δθ ₅₀ of the CuAl intermediate layer on the thickness of the Ti underlayer was examined.
The results are shown in FIGS. 12 and 13.

From FIG. 12, it can be seen that between the intermediate layer having the face-centered cubic structure and the non-magnetic support in Examples 11 to 15, 5 was formed.
It can be seen that by laminating the Ti underlayer having a thickness of nm or more, the diffraction peak intensity of each intermediate layer is 10 times or more as compared with the case where the underlayer is not present, and the crystallinity of the intermediate layer is significantly improved. In addition, from FIG.
It can be seen that by laminating the i underlayer, the degree of orientation Δθ ₅₀ was greatly reduced and the orientation was significantly improved.

Table 3 shows the peak intensities of the respective peaks that can be observed in the X-ray diffraction image, respectively when the underlayer is not laminated and when a Ti underlayer having a thickness of 5 nm is laminated.

[0073]

[Table 3] Change in X-ray diffraction peak intensity of each intermediate layer with or without Ti underlayer (unit is arbitrary intensity) Ti underlayer intermediate layer No peak (5 nm thickness) Cu (111) 18025 164582 (200) 2525-0 (311) 372-0 (222) 647 7353 Ni (111) 7832 97890 (200) 722 304 (220) 221 213 (311) 196 170 (222) 274 3038 NiCuTa (111) 7656 130682 (200) 531-0 (311) 201 ~ 0 (222) 291 4455 Al (111) 4505 82082 (200) 387-0 (311) 280-0 (222) 264 4000 CuAl (111) 6241 22312 (222) 372 903. From the results shown in Table 3, it can be seen that by stacking the Ti underlayer, the (111) and (222) peak intensities of the intermediate layer greatly increase, while the peak intensities of other peaks decrease. . This result indicates that the presence of the Ti underlayer causes the intermediate layer to have a strong (111) orientation and the crystallinity to be greatly improved.

As described above, from FIG. 12, FIG. 13 and Table 3, Ti
By laminating the underlayer between the intermediate layer and the non-magnetic support, the intermediate layer satisfies the conditions (2) and (3), which are the conditions for realizing the preferable perpendicular magnetization film, and therefore, It can be seen that a preferable perpendicular magnetization film can be realized.

Example 16 On a non-magnetic support made of a slide glass substrate, a Ti underlayer and Ni were formed by a magnetron type sputtering device.
A CuTa intermediate layer and a magnetic layer were sequentially laminated to manufacture a magnetic recording medium as shown in FIG. The film forming conditions of the underlayer, the intermediate layer and the magnetic layer at this time are as follows.

Degree of background vacuum: 1.3 × 10 ⁻⁴ Pa Temperature of non-magnetic support: Room temperature Sputtering power: DC300W Magnetic layer Total sputtering gas pressure: 2.0 Pa Gas composition: Ar and oxygen total gas flow rate: 50 SCCM target : Co ₆₈ Pt ₂₃ B ₉ (atomic%) composition alloy (diameter 10 cm x thickness 4 mm) Film thickness: 100 nm Intermediate layer Introduced gas: Ar gas total gas flow rate: 100 SCCM film thickness: 200 nm Target: Ni ₄₅ Cu ₅₀ Ta
Alloy of ₅ (atomic%) composition (diameter 10 cm × thickness 4 mm) Underlayer introduction gas: Ar gas total gas flow rate: 100 SCCM film thickness: 5 nm target: Ti Oxygen for forming the magnetic layer under the above conditions Various magnetic recording media were manufactured by changing the partial pressure, the perpendicular anisotropy magnetic field Hk and the perpendicular coercive force Hcv were obtained for these, and the relationship between them and the oxygen partial pressure PO ₂ was obtained. The results are shown in FIGS. 14 and 15.

Example 17 In Example 16, 100% was used instead of the intermediate layer and the underlayer.
A magnetic recording medium was manufactured by repeating Example 16 except that a Pt layer having a thickness of nm was used. As in Example 16, the perpendicular anisotropy magnetic field Hk, the perpendicular coercive force Hcv, and the oxygen partial pressure P were obtained.
The relationship with O ₂ was investigated. The results are shown in FIGS. 14 and 15. The Pt layer stacking conditions are such that the best perpendicular magnetic characteristics can be obtained when a single intermediate layer is used.

NiC of Examples 16 and 17
When the crystallinity and orientation of the uTa layer and the Pt layer were examined by an X-ray diffraction method, the degree of orientation Δ of the (111) peak of the Pt layer was found.
theta _{5 0} is 7.0 to 8.0 (deg.), the integrated intensity ratio _I 311 _{/ I 222} of the peak intensity was 0.02 to 0.04. On the other hand, the degree of orientation Δθ ₅₀ of the (111) peak of the NiCuTa layer was 4.5 to 6.1 (deg.), And the integrated intensity ratio I ₃₁₁ / I ₂₂₂ of the peak intensity was 0.01 or less. All of these results satisfy the conditions (2) and (3) of the intermediate layer for realizing the above-mentioned preferable perpendicular magnetization film, and therefore these results show that Ti
By stacking the underlayer, the NiCuTa layer becomes stronger (1
11) Oriented, which indicates that its crystallinity and orientation were improved.

By the way, the saturation magnetic flux density Bs of the magnetic layer obtained in Example 16 is about 1 to 1.2 T, and the above-mentioned formula (1) (104 / 4π) × for obtaining a good perpendicular magnetization film is obtained. By substituting the numerical value (1 to 1.2T) of the saturation magnetic flux density Bs into Hk ≧ Bs (1), the perpendicular anisotropic magnetic field Hk required for practical use is about 800.
14, the oxygen partial pressure range in which the perpendicular anisotropy magnetic field Hk of the magnetic recording media of Examples 16 and 17 is more than this value is about the same. The oxygen dependency and the magnitude of the perpendicular anisotropy magnetic field Hk are about the same as those of the sixteenth embodiment and the seventeenth embodiment. As is clear from FIG. 15, the perpendicular coercive force Hcv of the magnetic recording medium of Example 16 is larger than that of the magnetic recording medium of Example 17 using the Pt intermediate layer. Therefore, good magnetic properties can be realized by forming the Pt intermediate layer as in Example 17, but even when the NiCuTa intermediate layer that can be formed at a lower cost than the Pt intermediate layer is formed as in Example 16, the non-magnetic support is formed. It was found that by forming an underlayer between the body and the intermediate layer, perpendicular magnetic characteristics equivalent to or higher than the case of forming the Pt intermediate layer can be realized.

Example 18 In Example 16, the oxygen partial pressure PO ₂ at the time of forming the magnetic layer was 0.047 Pa, and the distance between the magnetic layer and the intermediate layer was 20 nm.
A magnetic recording medium using a thick Fe ₉₆ Si ₄ (atomic%) soft magnetic layer was manufactured, and a perpendicular anisotropic magnetic field Hk and a perpendicular coercive force H were obtained.
cv was calculated. As a result, the perpendicular anisotropy magnetic field H of this embodiment is obtained.
k is 960 kA / m, and the perpendicular coercive force Hcv is 182.
It was kA / m. This value is sufficiently larger than the value of the perpendicular anisotropy magnetic field Hk (about 800 kA / m or more) necessary for practical use, and therefore the magnetic recording medium obtained in this example has good perpendicular magnetic characteristics. Met.

Example 19 In Example 16, the intermediate layer was formed of Fe ₁₅ N having a thickness of 500 nm.
Example 1 except using an i ₈₀ Ta ₅ (atomic%) layer
A magnetic recording medium was manufactured by repeating 6 and the relationship between the perpendicular coercive force Hcv and the oxygen partial pressure PO ₂ was investigated.

FIG. 17 shows the oxygen partial pressure PO ₂ dependency of the perpendicular coercive force Hcv of Examples 18 and 17. FeNi
In the case of Example 18 in which the Ta intermediate layer and the Ti underlayer were combined, the oxygen partial pressure PO _{2 at which} the maximum value of the coercive force was obtained was higher than that in Example 17 in which the Pt intermediate layer was used. Although the oxygen concentration is shifted to the higher side, the tendency of the maximum value itself and the oxygen partial pressure PO ₂ dependency is almost the same.

FIG. 19 shows a perpendicular magnetization curve when the FeNiTa intermediate layer and the Ti underlayer are used. As is clear from FIG. 19, it is found that this magnetic recording medium maintains high squareness.

Further, I ₃₁₁ / I ₂₂₂ of the FeNiTa intermediate layer in Example 19 is 0.3 to 0.5, (11
1) The peak orientation degree Δθ ₅₀ is 3.8 to 5.5 (de).
g. )Met. These values all satisfy the conditions (2) and (3), which are the conditions for the intermediate layer from which the preferable perpendicular magnetization film is obtained, and therefore, by stacking the Ti underlayer, the FeNiTa intermediate layer is strongly strengthened. (111) orientation was possible, and its crystallinity and orientation could be improved. Therefore, it was possible to realize the perpendicular magnetic characteristics comparable to those of the Pt intermediate layer without the underlayer.

Example 20 In Example 16, the intermediate layer was formed of Fe ₆₀ Co having a thickness of 5 nm.
₄₀ (atomic%) layer is used, and oxygen partial pressure P at the time of forming the magnetic layer
A magnetic recording medium was manufactured with O _{2 set} to 0.047 Pa, and a perpendicular anisotropic magnetic field Hk and a perpendicular coercive force Hcv were obtained. As a result, the perpendicular anisotropy magnetic field Hk is 1150 kA / m,
The perpendicular coercive force Hcv was 175 kA / m. This value is the value of the perpendicular anisotropy magnetic field Hk (about 80
0 kA / m or more), showing good perpendicular magnetic characteristics.

[0086]

According to the magnetic recording medium of the present invention, it is possible to relax the conditions of oxygen partial pressure at the time of film formation for obtaining a magnetic thin film having desirable magnetic characteristics, particularly a high perpendicular anisotropy magnetic field. Further, the magnetic recording medium can be manufactured with high reproducibility and high yield. Furthermore, by providing the soft magnetic layer between the magnetic layer and the intermediate layer, it is possible to improve the magnetic recording output and the overwrite characteristic of the magnetic recording medium.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a magnetic recording medium according to a basic aspect of the present invention.

FIG. 2 is a cross-sectional view of a magnetic recording medium according to another aspect of the present invention.

FIG. 3 is a cross-sectional view of a magnetic recording medium according to another aspect of the present invention.

FIG. 4 is a cross-sectional view of a magnetic recording medium according to another aspect of the present invention.

FIG. 5 is a degree of orientation Δθ of the intermediate layer of the magnetic recording medium of the present invention.
It is a figure which shows the relationship between ₅₀ and the perpendicular anisotropy magnetic field Hk.

FIG. 6 is an integrated intensity ratio I of the intermediate layer of the magnetic recording medium of the present invention.
It is a figure which shows the relationship between ₃₁₁ / _I222 and the perpendicular anisotropy magnetic field Hk.

FIG. 7 is a diagram showing an example of an X-ray diffraction image of an Au intermediate layer.

FIG. 8 is a peak intensity of a P _Co peak of the magnetic layer of the magnetic recording medium of the present invention and an integrated intensity ratio I ₃₁₁ / I of the intermediate layer.
It is a figure which shows the relationship with ₂₂₂ .

FIG. 9 shows the total oxygen partial pressure range (0 to 0) in the magnetic recording medium.
It is a figure which shows the relationship between 0.07 Pa) and the perpendicular anisotropy magnetic field Hk.

FIG. 10 is an output characteristic diagram of magnetic recording showing an output of magnetic recording of a magnetic recording medium.

FIG. 11 is a perpendicular magnetization curve diagram of a magnetic film in a magnetic recording medium.

FIG. 12 is a diagram showing the relationship between the (111) peak intensity of the intermediate layer and the thickness of the Ti underlayer.

FIG. 13 is a diagram showing the relationship between the orientation degree Δθ50 of the intermediate layer and the thickness of the Ti underlayer.

FIG. 14 is a diagram showing the relationship between the oxygen partial pressure during film formation of the magnetic layer and the perpendicular anisotropic magnetic field of the magnetic layer.

FIG. 15 is a diagram showing the relationship between the oxygen partial pressure during film formation of the magnetic layer and the perpendicular coercive force of the magnetic layer.

FIG. 16 is a diagram showing the relationship between the oxygen partial pressure when forming a magnetic layer and the perpendicular coercive force of the magnetic layer.

FIG. 17 is an example of a perpendicular magnetization curve diagram of the magnetic recording medium of the present invention.

[Explanation of symbols]

 1 non-magnetic support 2 intermediate layer 3 magnetic layer 4 underlayer 5 soft magnetic layer 6 protective layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiko Hayashi 6-735 Kitashinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Koichi Aso 6-735 Kitashinagawa, Shinagawa-ku, Tokyo No. Sony Corporation

Claims (9)

[Claims] 1. A non-magnetic support having the following composition formula: (Co _a Pt _b B _c ) _100-x O _x (where a, b, c and x are atomic%, A magnetic layer represented by the formula: a = 100-bc; 0 ≦ b ≦ 50; 0.1 ≦ c ≦ 30; and 0 <x ≦ 15) is formed via an intermediate layer. A magnetic recording medium, wherein the intermediate layer has a face-centered cubic structure. 2. An orientation degree Δθ ₅₀ obtained from a rocking curve of a (111) peak of an X-ray diffraction image of the intermediate layer having a face-centered cubic structure is represented by the following formula Δθ ₅₀ ≦ 10 (deg.). The magnetic recording medium according to claim 1. 3. The integrated intensity ratio I ₃₁₁ / I ₂₂₂ between the (311) peak and the (222) peak of the X-ray diffraction image of the intermediate layer having a face-centered cubic crystal structure is expressed by the following formula I ₃₁₁ / I ₂₂₂ ≦ 0. The magnetic recording medium according to claim 1, represented by 4. The intermediate layer comprises Al, Ni, Cu, Rh, P
The magnetic recording medium according to claim 1, containing at least one of d, Ag, Ir, Pt, Au, Fe, and Co. 5. The magnetic recording medium according to claim 1, further comprising a soft magnetic layer formed between the magnetic layer and the intermediate layer. 6. The magnetic recording medium according to claim 5, wherein the soft magnetic layer has a body-centered cubic structure or a face-centered cubic structure. 7. The soft magnetic layer is a FeSi film.
The magnetic recording medium described. 8. The magnetic recording medium according to claim 1, further comprising an underlayer containing at least Ti or Cr formed between the non-magnetic support and the intermediate layer. 9. The magnetic recording medium according to claim 8, further comprising a soft magnetic layer formed between the magnetic layer and the intermediate layer.