JPH07121856A - Magnetic recording medium and its production - Google Patents

Abstract

PURPOSE:To produce a magnetic recording medium adaptable to the increase of recording density by improving horizontal magnetization characteristics. CONSTITUTION:This magnetic recording medium consists essentially of a nonmagnetic substrate, an under film, a magnetic film, a protective film and a lubricative film and further contains a film of CraOb (a=1 and 0.1<=b<=1.4), TicOd (c=1 and 0.8<=d<=1.8) or NiePfOg (e=1, 0.05<=f<=0.25 and 0.002<=g<=0.02) interposed between the substrate and under film.

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 in which various films are sequentially laminated on a non-magnetic substrate so as to be integrated, and more specifically, a magnetic recording medium which can cope with high recording density and a manufacturing method thereof. It is about.

[0002]

2. Description of the Related Art In a conventional magnetic recording medium, a base film, a magnetic film, a protective film and the like are sequentially formed on an Al substrate plated with Ni-P by a sputtering method or the like, and then a lubricant is coated on the surface. It is made by.

Among the above various films, the magnetic film is
For example, JP-A-61-292219 and JP-A-62-1922
239420, or Japanese Patent Laid-Open No. 62-137720.
As disclosed in Japanese Patent Publication No.
It has been proposed to form a three-element or four-element alloy containing b, Ta, Cr, Ni, etc. by a sputtering method or the like. Further, as the base film, for example, Japanese Patent Laid-Open No.
Cr or Cr alloys are used as shown in JP-A-257618, JP-A-63-106917, or JP-A-61-292219.

Furthermore, recently, as a non-magnetic substrate,
In order to increase the recording density, it is considered to change the material from a conventional Al substrate to a glass or carbon substrate which is light and strong and has excellent flatness.

[0005]

However, even if the glass or carbon substrate is used as it is instead of the conventional Al substrate as the non-magnetic substrate, some of the elements present on the surface of the glass or carbon substrate are used. Is Cr
Alternatively, H ₂ O and H _{2 which} are diffused into a base film made of a Cr alloy or retained (included) in pores or grain boundaries existing in a glass or carbon-based substrate are released. Due to the diffusion of ions, for example, the coercive force (Hc) in the magnetic film is lowered and the hysteresis of the magnetization represented by the squareness ratio becomes unsuitable, so that high recording density may not be achieved.

Therefore, the magnetic recording medium disclosed in Japanese Patent Laid-Open No. 61-222021 proposed as an improvement is ZrO ₂ , MgF ₂ , In ₂ O between the non-magnetic substrate and the underlying film.
_3, the SnO ₂ or the like are interposed, the magnetic recording medium described in JP-A-1-173427 is Cr, Mo, Ta, W,
Two different layers of films selected from V, Ti, Zr, and Cu are interposed to improve magnetic properties and mechanical properties, respectively. However, Cr
The intervening film formed between the base film and the non-magnetic substrate not only suppresses the movement of disturbance elements or ions from the non-magnetic substrate to the magnetic film, but also controls the film forming conditions of the intervening film. The ground film and the magnetic film must be in a shape suitable for magnetic recording. In particular, as the orientation of the Co magnetic film, it is necessary to give priority to the orientation of the Co (110) plane contributing to the horizontal magnetization while suppressing the orientation of the Co (002) plane contributing to the vertical magnetization.

[0007]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive studies to solve the above problems and achieve a higher recording density. As a result, a non-magnetic substrate, a base film, a magnetic film, a protective film and a lubrication film A magnetic recording medium having a film as a basic structure, wherein a non-magnetic substrate, a base film, a magnetic film, a protective film, and a lubricating film are basically formed between a non-magnetic substrate and a base film. , The intervening film interposed between the non-magnetic substrate and the base film is Cr _a O _b , c in which a = 1 and b = 0.1 to 1.4.
= 1, d = 0.8 to 1.8, Ti _c O _d , e = 1,
A magnetic recording medium having a composition selected from Ni _e P _f O _g in which f = 0.05 to 0.25 and g = 0.002 to 0.02 and a manufacturing method thereof have been found. It is a thing.

Each component of the magnetic recording medium of the present invention will be described. The non-magnetic substrate, undercoating film, magnetic film, protective film and lubricating film are not particularly limited in their materials and compositions, but may be known ones. It can be appropriately selected and used, and the film forming method is not particularly limited. For example, as the non-magnetic substrate, a glass-based substrate such as canasite glass or tempered glass or a carbon-based substrate can be used. Further, as described above, a base film made of Cr or a Cr alloy may be used, and a magnetic film containing Co as a main component may be formed by a sputtering method.

The intervening film formed between the non-magnetic substrate and the base film is Cr _a O _b (a =
1, b = 0.1~1.4), Ti c O d (c = 1, d =
_{0.8~1.8), Ni e P f O} g (e = 1, f = 0.
Co (110), which has a composition selected from the range of 05 to 0.25, g = 0.002 to 0.02), has a function of preventing diffusion of gas or ions, and is suitable for horizontal magnetic recording. ) Create a substrate on which an oriented magnetic film grows.

Cr _a with a = 1 and b = 0.1-1.4
The intervening film having a composition of O _b is formed by reactive sputtering in an argon gas atmosphere containing 0.2 to 2% of oxygen or a Cr target containing 0.1 to ₂ vol% of O ₂ . The film is formed by a sputter or the like. The film forming temperature of the Cr _a O _b film is set to 100 to 300 ° C., and the film forming temperature of the Cr base film is set to 300 to 500 ° C. The intervening film having a composition of Ti _c O _d in which c = 1 and d = 0.8 to 1.8 is reactive sputtered in an argon gas atmosphere containing 0.2 to 2% of oxygen, or 0.
A film is formed by sputtering or the like using a Ti target to which 1 to ₂ vol% O ₂ is added. In addition, this Ti _c
The film forming temperature of the _Od film is set to 30 to 300 ° C, and the film forming temperature of the Cr underlayer film is set to 300 to 500 ° C. e =
1, f = 0.05 to 0.25, g = 0.002 to 0.0
Interlayer having a composition of a 2 Ni _e P _f O _g was added reactive sputtering or 0.1～2Vol% of O _2, the oxygen and argon gas atmosphere was added 0.2 to 2% The film is formed by sputtering using a NiP target. The film forming temperature of this Ni _e P _f O _g film was 3
The temperature is set to 0 to 100 ° C., and the Cr underlayer deposition temperature is 15
It is set to 0 to 300 ° C.

[0011]

The magnetic recording medium of the present invention has the above-mentioned Cr _a O _b , T
The intervening film having a kind of composition selected from i _c O _d and Ni _e P _f O _g prevents diffusion of gas or ions, and can reliably protect the underlying film immediately above. Moreover, the Co (110) axis is oriented perpendicularly to the non-magnetic substrate in the magnetic film by the intervening film having the above-mentioned configuration, and as a result, the horizontal magnetization performance can be improved.

[0012]

EXAMPLES Examples of the present invention will be shown below.

[0013] [Examples 1-3, Comparative Examples 1-3]; by conventional sputtering, the interlayer 3.5-inch non-magnetic substrate (Cr _a O _b or Ti _c O _d or Ni _e P _f O
_g ), a base film, a magnetic film, and a protective film are sequentially formed, and a perfluoropolyether-based lubricant is applied on the uppermost surface of Examples 1 to 1.
The magnetic recording medium of No. 3 was manufactured, and B-
The shift was measured and shown in Table 2. The constitutional contents of the above-mentioned non-magnetic substrate and various films are shown in Table 1. Also, B-
The shift measurement conditions were a thin film head having a gap length of 0.35 μm and a track width of 6.9 μm, and a flying height of 2.5 microinches and a radius of 20 mm. The modulation code is M.I. F. M. The recording pattern was evaluated by B6D9. On the other hand, a 3 × 4 cm test piece was cut out from each magnetic recording medium, and the Co (110) plane (2θ =
74 °) orientation and Co (002) plane (2θ = 44
Orientation) was measured to determine whether or not it was in a state suitable for horizontal magnetic recording. Further, regarding magnetic characteristics, a 7 mm square sample was cut out from each magnetic recording medium, and coercive force (Hc), remanent magnetization * film thickness (Br) were measured by a vibration type magnetic characteristic device (VSM).
.Delta.) And squareness ratio (S ^* ) were measured. In Table 1, the film forming temperatures of various films are measured with a radiation thermometer. Further, the magnetic recording media of Comparative Examples 1 to 3 having exactly the same configuration except that the above-mentioned intervening film was not formed were manufactured, and the same test was performed.

[0014]

[Table 1]

[0015]

[Table 2]

[Embodiment 4] The magnetic recording medium of Embodiment 4 was manufactured in the same manner as in Embodiment 1 except that the Cr target containing 0.5% oxygen was used as the target for the intervening film. Table 3 shows the result of the test. The results of Comparative Example 1 are shown in Table 3 for comparison.

[0017]

[Table 3]

[Examples 5 to 7] Examples 5 to 7 are exactly the same as Examples 1 to 3 except that the target for the intervening film is replaced by pure Ti (Ar atmosphere containing 1.0% of oxygen). Table 4 shows the results of manufacturing the magnetic recording medium of No. 1 and performing the same test. For comparison, the results of Comparative Examples 1 to 3 are shown in Table 4.
It was written side by side.

[0019]

[Table 4]

[Embodiment 8] The magnetic recording medium of Embodiment 8 was manufactured in the same manner as in Embodiment 1 except that the Ti target containing 0.5% oxygen was used as the target for the intervening film. Table 5 shows the result of the test. The results of Comparative Example 1 are also shown in Table 5 for comparison.

[0021]

[Table 5]

[Examples 9 to 11] Example 9 was exactly the same as Examples 1 to 3 except that the target for the intervening film was changed to Ni ₁ P _0.2 (Ar atmosphere containing 1.0% oxygen). ~
11 magnetic recording media were manufactured and the same test was performed. The results are shown in Table 6. The results of Comparative Examples 1 to 3 are also shown in Table 6 for comparison.

[0023]

[Table 6]

[0024] [Example 12]; except that the target for the intervening film was changed to Ni ₁ P _0.2 target oxygen 0.5% containing, producing a magnetic recording medium of Example 1 in exactly the same manner as in Example 12 The results of the same tests are shown in Table 7. The results of Comparative Example 1 are also shown in Table 7 for comparison.

[0025]

[Table 7]

[0026]

As described above, the magnetic recording medium of the present invention has magnetic characteristics suitable for high density recording.

Further, the intervening film prevents diffusion of gas or ions, and moreover, the intervening film prevents Co in the magnetic film.
The (110) axis can be oriented perpendicular to the non-magnetic substrate, resulting in improved horizontal magnetization performance.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a magnetic recording medium of the present invention.

Claims (4)

[Claims] 1. A magnetic recording medium having a non-magnetic substrate, a base film, a magnetic film, a protective film, and a lubricating film as a basic structure, wherein an intervening film interposed between the non-magnetic substrate and the base film is a = 1,
Cr _a O _b where b = 0.1 to 1.4, c = 1, d =
Ti _c O _{d of} 0.8 to 1.8, e = 1, f = 0.0
5 to 0.25, which is g = 0.002~0.02 Ni _e
A magnetic recording medium having a composition selected from P _f O _g . 2. The magnetic recording medium according to claim 1, wherein the non-magnetic substrate is a glass or carbon-based substrate. 3. The magnetic recording medium according to claim 1, wherein the underlayer film contains Cr as a main component. 4. A = 1, b = 0.1 on a non-magnetic substrate.
Cr _a O _{b of} 1.4, c = 1, d = 0.8 to 1.8
Ti _c O _d , e = 1, f = 0.05 to 0.25,
interlayer is formed that comprises a composition selected from a _{g = 0.002~0.02 Ni e P f O} g, underlying film on the surface of the interlayer, a magnetic film, a protective film and a lubricant film formed A method of manufacturing a magnetic recording medium, characterized in that a film is formed.