JP2850312B2 - Magnetic recording medium and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium using a glass substrate, and more particularly to a magnetic recording medium suitable for high-density recording having a high coercive force Hc.

[0002]

2. Description of the Related Art In recent years, magnetic recording media capable of high-density recording have been demanded. For this reason, efforts have been made to develop magnetic recording media having a higher coercive force Hc. In the field of magnetic disks, sputter-type disks that can cope with high-density recording have become the mainstream, instead of conventional coating-type disks.

[0003] The magnetic disk of the above-mentioned sputter type comprises an Al substrate plated with NiP and a Cr underlayer, a Co-Ni film.
Alternatively, a Co-Ni-Cr magnetic film is provided in this order, and a carbon film and a lubricating layer are provided on this magnetic film. With the improvement in recording density, a glass substrate capable of reducing the flying height of the head has appeared, and low noise Co-Cr-Ta and Co-Cr-Pt have been developed for magnetic films.

In order to further increase the coercive force Hc, for example, Japanese Patent Application Laid-Open No. 1-256017 discloses a Co-Cr-Ta
A technique using a magnetic layer made of -Pt is described,
Japanese Patent Publication No. 4-50653 discloses a bias sputtering technique for forming a film while applying a negative bias voltage.

[0005]

However, in any of the above-mentioned technologies, when a glass substrate excellent in the low flying height characteristic is used, a high-performance magnetic material having a coercive force Hc exceeding 2200 (Oe) is used. No disc was obtained. An object of the present invention is to provide a magnetic recording medium having a coercive force Hc of 2200 (Oe) or more and a method of manufacturing the same.

[0006]

In order to solve the above problems , at least one of V and Mo is provided on a glass substrate.
Pre-coating film containing the is formed, a magnetic recording medium in which a magnetic film made of a quaternary alloy of underlayer and Co-Cr-Ta-Pt of Cr are formed in this order over the pre-coating film, the base film Lattice plane of Cr crystal of Cr (200)
Also, the lattice plane Co (110) of the Co crystal in the magnetic film is both lower than the X-ray diffraction intensity when preferentially oriented parallel to the glass substrate surface.

Further, according to the manufacturing method of the present invention, a precoat film is formed of a material containing at least one of V and Mo , and a base film and a magnetic film are formed by sputtering while applying a negative bias voltage. It is formed.

[0008]

[Function] At least one of V and Mo on a glass substrate.
A pre-coat film including various types is formed, and a base film made of Cr and a magnetic film made of a quaternary alloy of Co-Cr-Ta-Pt are formed on the pre-coat film in this order.
By making the lattice plane Cr (200) of the r crystal and the lattice plane Co (110) of the Co crystal in the magnetic film both lower than the X-ray diffraction intensity when preferentially oriented parallel to the glass substrate plane. The crystallinity of the growing Cr crystal and Co crystal is reduced, and the coercive force Hc is improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial sectional view showing an example of a magnetic disk according to the present invention. This magnetic disk 1 is C
The magnetic film 2 composed of a quaternary alloy of o-Cr-Ta-Pt is
It is formed on a glass substrate 5 provided with a base film 3 made of and a precoat film 4. For use as the magnetic disk 1, a carbon lubricating layer (not shown) is provided on the magnetic film 2, and a lubricant is further applied thereon.

The lattice planes of the Cr crystal (body-centered cubic) of the underlayer 3 and the Co crystal (hexagonal) of the magnetic film 2 are C
Lattice lattice plane Cr (200) and Co crystal lattice plane C
Compared with the X-ray diffraction intensity when both o (110) are preferentially oriented parallel to the glass substrate surface, Cr (200) and C
The X-ray diffraction intensity of o (110) is low. Also,
Similarly, the X-ray diffraction intensity of Cr (110) is high. The magnetic disk 1 according to the present invention having such a lattice plane has a coercive force Hc of 2200 (Oe) or more, and can even exceed 3200 (Oe).

The above contents will be specifically described. FIG. 9 is a conceptual diagram showing a unit cell of a Cr crystal and a Co crystal in which conventional Cr (200) and Co (110) are preferentially oriented parallel to the glass substrate surface. In X-ray diffraction by the 2θ / θ method, X-rays are diffracted only from the lattice plane parallel to the plane of the glass substrate 5.
The diffraction intensity of (200) and Co (110) is strong.

However, when Cr (200) and Co (110) are preferentially oriented parallel to the surface of the glass substrate 5 as described above, as shown in FIG. Is no longer parallel to Therefore, this Cr (1)
The diffraction intensity of 10) decreases.

FIG. 2 is a conceptual diagram showing a unit cell of a Cr crystal of the base film 3 in which Cr (110) according to the present invention is preferentially oriented parallel to the glass substrate surface. FIG. 2 and FIG.
As is clear from the comparison of Cr (11
The diffraction intensity of 0) becomes stronger than that of FIG. on the other hand,
FIG. 3 shows Cr (200) and Co (11) according to the present invention.
9), the diffraction intensity of Cr (200) and Co (110) in FIG. 3 is lower than that in FIG. 9 as is clear from comparison with FIG.

That is, C in the base film 3 according to the present invention is
The X-ray diffraction intensities of r (200) and Co (110) in the magnetic film 2 are represented by I _{Cr (200)} and I _{Co (110)} , respectively, and the X-ray diffraction of Cr (200) and Co (110) in FIG. _Assuming that the diffraction intensities are I _{OCr (200)} and I _{OCo (110)} respectively, (I _{Cr (200)} / I _{OCr (200)} ) <1, but preferably (I _{Cr (200)} / I _{OCr ( 200)} ) ≦ 0.4. Also, (I _{Co (110)} / I _{OCo (110)} ) <1, but preferably (I _{Co (110)} / I _{OCo (110)} ) ≦ 0.6.

Further, the Cr in the underlayer 3 according to the present invention is
Assuming that the X-ray diffraction intensity of ₍₁₁₀₎ is I _{Cr (110)} , FIG.
The X-ray diffraction intensity of Cr (110) at 0 is _calculated as I _{OCr (110)}
(I _{Cr (110)} / I _{OCr (110)} )> 1, but preferably (I _{Cr (110)} / I _{OCr (110)} ) ≧ 1.35.
It is.

Next, an example of a method of manufacturing the magnetic disk 1 according to the present invention will be described. As described above, the preferred orientation planes of Cr in the underlayer 3 and Co crystals in the magnetic film 2 change. Is most important, and there is no limitation on any manufacturing method that can cause this change in the orientation plane.

FIG. 4 is a schematic view showing an example of a sputtering apparatus according to the present invention. In FIG. 1, a sputtering apparatus 6 includes a target 8 and a magnetic disk holder 9 in a vacuum layer 7, and an inlet 10 for an inert gas such as Ar and a vacuum exhaust port 11 are provided. The target 8 is connected to a DC power supply 12 for sputtering, and the magnetic disk holder 9 is connected to a DC power supply 13 for bias.
Is connected.

In order to manufacture the magnetic disk 1 according to the present invention using the sputtering apparatus 6, first, the precoat film 4 which has been formed from a material containing at least one of V and Mo by a sputtering method or the like. The attached glass substrate 5 is attached to the magnetic disk holder 9. And the vacuum exhaust port 1
After evacuation from 1, for example, Ar gas is introduced from the inlet 10, and a DC voltage is applied by the DC power supply 12 for sputtering and the DC power supply 13 for bias.

As described above, when a Cr underlayer 3 or a Co—Cr—Ta—Pt quaternary alloy magnetic film 2 is formed while applying a negative bias voltage to the glass substrate 5 with the precoat film 4, Glass substrate 5 flying from target 8
Some of the atoms such as Cr adhered to the surface are sputtered under the influence of the negative bias voltage, causing a change in the preferential orientation plane, and having the lattice plane according to the present invention, and the coercive force Hc2.
The magnetic disk 1 of 200 (Oe) or more can be obtained.

Next, embodiments according to the present invention will be described in more detail. Example 1 A precoat film 4 made of V was formed on a 3.5-inch glass substrate 5 by DC magnetron at a thickness of 60 °. The film formation conditions at this time were as follows: the ultimate vacuum was 2 × 10 ⁻⁶ Torr.
r, Ar sputtering gas pressure 2 mTorr, glass substrate 5
Was heated to 200 ° C. After the formation of the precoat film 4, the glass substrate 5 was cooled and removed from the vacuum device.

Next, the glass substrate 5 with the pre-coated film 4 is mounted on the magnetic disk holder 9 of the sputtering device 6, and the glass substrate 5 is applied with a bias voltage of -200 V to make the base film 3 made of Cr 4000 °. Co _75.2 Cr _9.4 Ta on the _5.7 Pt _{9 .7} magnetic film 2 quaternary alloy having the composition (each numerical value accompanying the atoms are at%) 2
The magnetic disk 1 was formed by forming a film of 50 °. At this time, the deposition conditions are as follows: ultimate vacuum degree is 2 × 10 ⁻⁶ Torr, Ar sputtering gas pressure is 2 mTorr, and heating temperature of the glass substrate 5 is 2 mm.
50 ° C.

For comparison with the present embodiment, a magnetic disk 1 (R-1) was prepared in exactly the same manner as in the above manufacturing method except that no bias voltage was applied. The crystal orientation of the magnetic films 2 of Examples 1 and R-1 was measured by an X-ray diffractometer, and the magnetic properties (coercive force Hc) were measured by a vibrating sample magnetometer (VSM).

The results for the obtained magnetic disk 1 are shown in FIGS. Figure 5 is a measurement chart of the X-ray diffraction intensity, as compared to R-1 magnetic disk 1 of this embodiment of the base film 3 Cr (200) and the magnetic film 2 Co
The strength of (110) was low and the strength of Cr (110) was high. FIG. 7 shows bias voltage-coercive force H
FIG. 13 is a c-line diagram, in which the coercive force Hc of the magnetic disk 1 of R-1 is 2100 (Oe), whereas the coercive force Hc of the present embodiment is 3100.
060 (Oe).

FIG. 8 shows an X-ray diffraction intensity ratio-coercive force H.
It is a c-line diagram, and A-C in a figure represents the following contents. In addition,
I in the following is the X-ray diffraction intensity of the magnetic disk 1 of each embodiment, and IO is the X-ray diffraction intensity of the magnetic disk 1 for comparison. A: X-ray diffraction intensity ratio of _{Cr (200)} ; A = I _{Cr (200)} / I _{OCr (200)} B: X-ray diffraction intensity ratio of _{Co (110)} ; B = I _{Co (110)} / I _{OCo (110)} C... X-ray diffraction intensity ratio of _{Cr (110)} ; C = I _{Cr (110)} / I _{OCr (110) As} shown in FIG. 0.08, B was 0.16, and C was 2.77 (the R-1, magnetic disk 1 is 1 for all A, B, and C).

Embodiments 2 to 4 The bias voltage applied to the glass substrate 5 of Embodiment 1 is -1.
00V (Example 2), -300V (Example 3), -40
Each of the magnetic disks 1 was manufactured in the same manner as in Example 1 except that the voltage was changed to 0 V (Example 4).

These results are also shown in FIGS. 5, 7 and 8. In FIG. 5, the magnetic disk 1 according to the present embodiment has Cr (200) and Co (110) compared to R-1.
Is low, and the strength of Cr (110) is high. Further, as shown in FIG. 7, the coercive force Hc of each of Examples 2 to 4 is 2450 (Oe) and 3100 (Oe), respectively.
(Oe) and 2800 (Oe).

Further, in FIG. 8, A of the magnetic disk 1 according to Examples 2 to 4 is 0.15, 0.0, respectively.
3,0.07, B is 0.26, 0.13, 0.26, C
Were 2.81, 2.93, and 1.38.

Example 5 A magnetic disk 1 was manufactured in the same manner as in Example 1 except that the thickness of the underlayer 3 was changed to 1000 °. The coercive force Hc of this magnetic disk 1 was 2300 (Oe). Further, a comparative magnetic disk 1 (R-2) to which no bias voltage was applied was also prepared.
It was as low as 00 (Oe).

FIG. 6 is a measurement chart of the X-ray diffraction intensity according to the present embodiment. The intensity of Cr (200) and Co (110) is lower than that of R-2.

Embodiment 6 In the same manner as in Embodiment 1 except that a Cr film 500 #, a carbon film 500 #, and a Mo film 60 # are formed in this order in place of the V pre-coat film 4 of Example 1 to obtain a pre-coat film 4. Thus, the magnetic disk 1 was manufactured. The coercive force Hc of this magnetic disk 1 was 3230 (Oe). Further, a comparison magnetic disk 1 (R-
3), but this coercive force Hc is 2150 (Oe).
Was low.

COMPARATIVE EXAMPLE 1 Instead of the precoat film 4 made of V in Example 1, a Cr film 60Å was formed, and was not taken out from the vacuum apparatus.
The magnetic disk 1 was manufactured in the same manner as in Example 1 except that the base film 3 made of Cr was formed at 2000 ° while applying a bias voltage of 200 V, but the coercive force Hc was 20.
It was as low as 50 (Oe).

As is apparent from the above results, the magnetic disk 1 according to the present invention formed by applying a negative bias voltage has the R-1 to R- formed without applying the negative bias voltage. 3 has a higher coercive force H than that of the magnetic disk 1
c. Further, the peak of the coercive force Hc has a bias voltage near -300 V, and the magnetic disk 1 of about 3100 (Oe) can be obtained. Further, as shown in Example 6, the coercive force H
A very high performance magnetic disk 1 with c3230 (Oe) was also obtained.

As is apparent from FIGS. 5 and 6, R-1 and R- formed without applying a negative bias.
The magnetic disk 1 of No. 2 has Cr (200) of the underlayer 3 and
Although Co in the magnetic layer 2 (110) is parallel to preferentially oriented in the glass substrate 5, the magnetic disk 1 of the embodiment of applying a negative bias, Cr (200) underlayer 3, a magnetic film
Crystal orientation is lowered with respect to the glass substrate surface of in 2 Co (110), Cr underlayer 3 (110) is a glass substrate 5
Tend to be preferentially oriented parallel to

[0034]

As described above, according to the present invention, a precoat film containing at least one of V and Mo is formed on a glass substrate, and Cr is formed on the precoat film. An underlayer and a magnetic film composed of a quaternary alloy of Co—Cr—Ta—Pt are formed in this order, and the lattice plane Cr (200) of the Cr crystal of the underlayer and the lattice plane Co of the Co crystal in the magnetic film are formed.
(110) is lower than the X-ray diffraction intensity when both are preferentially oriented parallel to the glass substrate surface, and the growing Cr
Since the crystallinity of the crystal and the Co crystal was reduced, the coercive force H
A magnetic recording medium capable of high-density recording with a very high c can be obtained.

Further, according to the manufacturing method of the present invention, the precoat film is formed of a material containing at least one of V and Mo , and the undercoat film and the magnetic film are formed by a sputtering method while applying a negative bias voltage. To form Cr
By preferentially orienting the (110) lattice plane parallel to the glass substrate surface, a magnetic recording medium capable of high-density recording can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a conceptual diagram showing a unit cell of a Cr crystal of a base film in which Cr (110) is preferentially oriented parallel to a glass substrate surface according to the present invention.

FIG. 3 shows Cr (200) and Co (11) according to the present invention.
Conceptual diagram showing orientation of 0)

FIG. 4 is a schematic view showing an example of a sputtering apparatus according to the present invention.

FIG. 5 is a measurement chart of X-ray diffraction intensity of Examples 1 to 4.

FIG. 6 is a measurement chart of X-ray diffraction intensity of Example 5.

FIG. 7 is a diagram showing bias voltage-coercive force Hc diagrams of Examples 1 to 4.

FIG. 8 is an X-ray diffraction intensity ratio-coercive force Hc diagram of Examples 1 to 4.

FIG. 9 is a conceptual diagram showing a unit cell of a conventional Cr crystal and Co crystal in which Cr (200) and Co (110) are preferentially oriented parallel to the glass substrate surface.

FIG. 10 is a conceptual diagram showing the orientation of conventional Cr (110).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic recording medium (magnetic disk), 2 ... Magnetic film, 3 ...
Base film, 4 precoat film, 5 glass substrate, 6 sputtering device, 7 vacuum layer, 8 target, 9 magnetic disk holder, 12 DC power source for sputtering, 13 DC power source for bias.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 5/66 G11B 5/85

Claims (2)

(57) [Claims] 1. At least V, Mo on a glass substrate
Among them, a precoat film containing one type is formed, and a base film made of Cr and Co—Cr—Ta are formed on the precoat film.
A magnetic recording medium in which a magnetic film made of a quaternary alloy of -Pt is formed in this order, wherein a lattice plane Cr (200) of a Cr crystal of the base film and a lattice plane C of a Co crystal in the magnetic film are formed.
A magnetic recording medium characterized in that the X-ray diffraction intensity of o (110) is both lower than the X-ray diffraction intensity when preferentially oriented parallel to the glass substrate surface. 2. A precoat film is formed on a glass substrate,
On this pre-coat film, a base film made of Cr and Co-C
In a method for manufacturing a magnetic recording medium in which a magnetic film made of a quaternary alloy of r-Ta-Pt is formed in this order, the pre-coat film is formed of a material containing at least one of V and Mo. A method for manufacturing a magnetic recording medium, wherein a ground film and a magnetic film are formed by a sputtering method while applying a negative bias voltage.