JP2000260020A - Magnetic recording medium and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure sufficient shock resistance to an unexpected collision of a magnetic head even when the thickness of a protective coat is reduced in a data are and to prevent a wear and breaking of the protective coat due to the contact and friction of the magnetic head in a CSS area. SOLUTION: When a magnetic film 3 and carbon-base protective coats 4, 5 which protect the magnetic film are disposed on a substrate 1 to produce the magnetic recording medium, the contact parts of the protective coats 4, 5 which come in contact with a magnetic head at the start or stop of the magnetic head are formed by an ion beam method using a gaseous hydrocarbon optionally in combination with at least one selected from Ne, Ar, Kr and Xe and then the protective coats 4, 5 are formed on the nearly entire surface of the magnetic recording medium by a sputtering method using N2 and at least one selected from H2, Ne, Ar, Kr and Xe. In other way, an amorphous carbon layer is formed on the entire surface of the recording medium by the sputtering method and then a DLC layer is formed in the CSS area by the ion beam method.

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 having excellent reliability and capable of high-density magnetic recording, a method of manufacturing the same, and a magnetic disk drive used as an auxiliary storage device of a computer.

[0002]

2. Description of the Related Art Magnetic disk drives used for storage devices such as large computers, workstations, personal computers and the like have become increasingly important year by year, and have been developed to have large capacity and small size. High density is indispensable for reducing the capacity and size of the magnetic disk drive. One technique for achieving this is to reduce the distance between the magnetic recording layer of the magnetic recording medium and the magnetic head.

Conventionally, a magnetic recording medium manufactured by sputtering has been provided with a protective film for the purpose of protecting the magnetic film from sliding by a magnetic head. Reducing the thickness of the protective film and reducing the distance between the surface of the protective film and the magnetic head are the most effective means for reducing the distance between the magnetic recording layer and the magnetic head. This protective film includes DC sputtering, RF sputtering (JP-A-5-174369), and CVD (JP-A-4-9369).
No. 0125) is most commonly used, and in order to obtain a protective film having higher strength, a method of mixing nitrogen atoms, hydrogen atoms, and the like into the film (Japanese Patent Application Laid-Open No. 62-246129). JP-A-5-225556).

[0004] In addition, in a general interface system between a magnetic recording medium and a magnetic head, minute irregularities are provided so that the magnetic head does not adhere to the magnetic recording medium on the magnetic recording medium when not operating. Contact start and stop (CSS) in which contact is stopped at a predetermined position, and the surface floats while maintaining an extremely small gap between the magnetic recording medium during operation, that is, when recording, reading, and waiting. There is a method. In a magnetic disk drive employing this method, as the protective film of the magnetic recording medium becomes thinner, the magnetic recording medium comes into contact with the magnetic head at the start and end of the operation, and wear and breakage of the protective film due to friction occur. The problem is getting worse. Also, during operation, as the distance between the surface of the protective film of the magnetic recording medium and the magnetic head is reduced, the problem of wear and destruction of the protective film due to unexpected contact becomes more serious.

[0005]

Conventionally, the protection film thickness of an area where CSS is performed (hereinafter referred to as a CSS area) is made thicker than the protection film thickness of an area where data is written (hereinafter referred to as a data area) so that durability is improved. Proposal to improve
However, in the situation where large capacity and miniaturization are required as in the present case, a sufficient effect cannot be obtained by simply changing the film thickness. That is, it is necessary to make the data area as large as possible in order to perform maximum recording within a limited disk area.
The S area and the data area are necessarily adjacent to each other. Under such circumstances, it is industrially difficult to greatly change the film thickness of the CSS area and the data area, and even if it is realized, when the head is sought between the CSS area and the data area, the reference position of the disk surface suddenly decreases. Causes a change in the attitude of the magnetic head. Therefore, the difference in film thickness could be at most about 5 nm, and the effect could not be obtained only by changing the thickness with a single film quality.

Hitherto, a proposal has been made that an area for performing CSS is mainly a diamond and a data area is a protective film in which graphite and diamond are mixed (Japanese Patent Laid-Open No. 3-272017).
However, in this case, when the thickness is reduced to about 10 nm, sufficient strength is not obtained in the CSS area. The protective film is easily destroyed.

Further, a proposal has been made in which the area for performing CSS has a graphite structure and the data area has an amorphous structure (JP-A-4-32021). However, a graphite structure thin film having a thickness of about 10 nm is resistant to CSS. Clearly not. Japanese Unexamined Patent Publication No. Hei 3-2720
No. 17 and Japanese Unexamined Patent Publication No. Hei 4-32021.
Even with the combination of Japanese Patent Application Laid-Open No. 0-23406, even when the protective film thickness in the data area is about 10 nm or less, the magnetic head has sufficient strength against unexpected collisions, It has not been possible to obtain a magnetic recording medium in which the protective film does not wear or break due to contact and friction between the magnetic recording medium and the magnetic head.

Further, when a protective film having properties suitable for the CSS area and the data area is used by the sputtering method, or when the thickness of only the CSS area is to be increased, magnetic recording is performed on the data area. Even if film formation is performed using a shielding plate or the like that is not in contact with the recording medium, sputter particles that wrap around the data area can be limited only to some extent due to the nature of sputtering, and the film quality of the CSS area and the data area is clearly separated. Also, it has been difficult to greatly change the film thickness in a short distance.

Also, ion beam deposition is known as a means for producing a protective film layer having a thinner film thickness and a stronger characteristic than a protective film layer mainly composed of carbon produced by sputtering. However, since the lifetime of the hot filament used for the ion gun is short, it is industrially difficult to form the protective film layer only by ion beam deposition.

The present invention has been made in view of the above-mentioned problems and problems. A first object of the present invention is to reduce the thickness of a protective film layer to about 10 nm or less in a data area,
Further, it is an object of the present invention to provide a method of manufacturing a magnetic recording medium in which the protection film is not destroyed due to contact and friction between the magnetic recording medium and the magnetic head at the start and end of the operation in the CSS area. That is, in a method of manufacturing a magnetic recording medium provided with a magnetic film and a protective film containing carbon as a main component that protects the magnetic film on a substrate, by using both the ion beam deposition method and the sputtering method, An object of the present invention is to provide a magnetic recording medium having sufficient shock resistance and flying stability in a data area and sufficient sliding reliability in a CSS area.

A second object of the present invention is to provide a magnetic recording medium obtained as a result of achieving the first object. A third object is to provide a magnetic storage device suitable for achieving both high recording density and high reliability by using a magnetic recording medium that has achieved the second object.

[0012]

In order to solve the above problems, the present invention mainly employs the following configuration.

In a method for manufacturing a magnetic recording medium having a magnetic film provided on a base and a protective film containing carbon as a main component for protecting the magnetic film, the protective film which comes into contact with the magnetic head when the magnetic head is started or stopped. Ne, A at the contact part
A film is formed by an ion beam method using at least one of r, Kr, and Xe and a hydrocarbon gas or only a hydrocarbon gas, and then protected by physical vapor deposition or chemical vapor deposition on substantially the entire surface of the magnetic recording medium. A method for manufacturing a magnetic recording medium for forming a film.

In a method for manufacturing a magnetic recording medium having a magnetic film and a protective film mainly composed of carbon for protecting the magnetic film provided on a base, a physical vapor deposition method or a chemical vapor deposition method is applied to substantially the entire surface of the magnetic recording medium. A protective film is formed by a vapor deposition method, and then at least one of Ne, Ar, Kr, and Xe and a hydrocarbon gas or a hydrocarbon are contacted with a contact portion of the protective film that contacts the magnetic head when the magnetic head is started or stopped. A method for manufacturing a magnetic recording medium in which a film is formed by an ion beam method using only gas.

In a magnetic recording medium provided with a magnetic film and a protective film mainly composed of carbon for protecting the magnetic film on a substrate, the magnetic head is in contact with the magnetic head when the magnetic head is started or stopped. The contact portion of the film is composed of a diamond-like (DLC) layer mainly composed of carbon and hydrogen, and an amorphous carbon layer mainly composed of carbon, or carbon and nitrogen, or carbon, nitrogen and hydrogen. A magnetic recording medium wherein a portion of the protective film other than a contact portion is mainly formed of an amorphous carbon layer made of carbon, or carbon and nitrogen, or carbon, nitrogen and hydrogen.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an outline of the structure, function and operation of the present invention will be described below. In a magnetic recording medium in which a magnetic film and a protective film mainly composed of carbon for protecting the magnetic film are provided on a base, contact of the protective film with the magnetic head when starting and / or stopping the magnetic head The portion of the protective film other than the contact portion is mainly composed of carbon and a diamond-like (DLC) layer mainly composed of carbon and hydrogen and an amorphous carbon layer mainly composed of carbon and nitrogen and containing hydrogen. It is made of an amorphous carbon layer made of nitrogen and containing hydrogen.

The reason why the contact portion of the protective film is composed of a diamond-like (DLC) layer mainly composed of carbon and hydrogen and an amorphous carbon layer composed mainly of carbon and nitrogen and containing hydrogen is that the magnetic head at the time of CSS is used. This is to provide sufficient strength to prevent the slide from being broken. The reason why the portion of the protective film other than the contact portion is mainly made of an amorphous carbon layer containing carbon and nitrogen and containing hydrogen is to provide sufficient strength against collision with a magnetic head.

Furthermore, it is desirable that the thickness of the portion of the protective film other than the portion of the protective film that comes into contact with the magnetic head when the magnetic head is started and / or stopped be 10 nm or less, and furthermore that the magnetic head be started and / or stopped. Sometimes, the thickness of the portion of the protective film that contacts the magnetic head is greater than the portion of the protective film other than the contact portion, and
nm or less, and the thickness change rate in the radial direction of the protective film at the boundary between the protective film at the contact portion and the protective film other than the contact portion is radially different at the portion of the protective film other than the contact portion. It is preferable that the rate of change is larger than the film thickness change rate and the value is 1.0 nm / mm or more.

The reason why the thickness of the portion of the protective film other than the portion of the protective film that contacts the magnetic head when starting and / or stopping the magnetic head is preferably 10 nm or less is as follows.
If the thickness is more than 10 nm, the distance between the magnetic head and the magnetic recording layer increases, which is not suitable for high recording density.
When the magnetic head is started and / or stopped, the portion of the protective film that is in contact with the magnetic head is thicker than the portion of the protective film other than the contact portion, and has a thickness of 20 nm.
The reason for being desirably the following is that while giving sufficient strength, if the thickness is more than 20 nm, the posture of the magnetic head is not stable at the time of startup, and the possibility of contact between the magnetic head and the magnetic recording medium increases. This is because

Further, the rate of change of the thickness of the protective film in the radial direction at the boundary between the protective film at the contact portion and the protective film other than the contact portion may be smaller in the radial direction at the portion of the protective film other than the contact portion. The reason why the ratio is preferably larger than the film thickness change rate and the value is preferably 1.0 nm / mm or more is that the film thickness of the portion of the protective film that comes into contact with the magnetic head when starting and / or stopping the magnetic head is short. By starting up as steeply as possible at a distance, the uniformity of the film thickness in the data area is ensured.
Alternatively, it is for ensuring the desired thickness of the protective film that comes into contact with the magnetic head when stopped.

The above-mentioned protective film is provided at least at least one of Ne, Ar, Kr, and Xe with hydrocarbon gas or hydrocarbon gas at a contact portion of the protective film that comes into contact with the magnetic head when the magnetic head is started and / or stopped. A film is formed by an ion beam method using only a hydrocarbon gas, and then a protective film is formed on substantially the entire surface of the magnetic recording medium by a sputtering method using at least one of H2, Ne, Ar, Kr, and Xe and N2. Or H2, N is applied to almost the entire surface of the magnetic recording medium.
A protective film is formed by a sputtering method using at least one of e, Ar, Kr, and Xe and N2, and then Ne is added to a contact portion of the protective film that comes into contact with the magnetic head when starting and / or stopping the magnetic head. , Ar, Kr, Xe
Can be formed by ion beam deposition using at least one of them and a hydrocarbon gas or only a hydrocarbon gas. When forming a film on the contact portion by an ion beam method, it is an effective means to provide a shield near the magnetic recording medium and to perform a means for preventing a film from being formed other than the contact portion.

Also, a magnetic storage device according to the present invention includes a magnetic recording medium, a drive unit for driving the magnetic recording medium, a magnetic head including a recording unit and a reproducing unit, and a magnetic head for the magnetic recording medium. The magnetic head has a magnetoresistive effect, wherein the magnetic head has means for inputting a signal to the magnetic head and means for processing a recording / reproducing signal for reproducing an output signal from the magnetic head. This is realized by configuring the magnetic recording medium with a magnetic recording medium having various configurations as described above.

Further, the magnetoresistive sensor portion of the magnetoresistive effect type magnetic head is formed between two shield layers made of a soft magnetic material which are separated from each other by a distance of 0.2 μm or less. The product of the thickness t of the magnetic layer of the magnetic recording medium having the above configuration and the residual magnetic flux density Br measured by applying a magnetic field in the relative running direction of the magnetic head with respect to the magnetic recording medium during recording is Br × t. Is 3.2 mA
(40 Gauss / micron) or more and 9.6 mA (120 Gauss / micron) or less.

It is the maximum that the magnetoresistive sensor portion of the magnetoresistive head must be formed between two shield layers made of a soft magnetic material which are separated from each other by a distance of 0.2 μm or less. Linear recording density of 220 kFCI
Is insufficient to obtain a sufficient reproduction output in a magnetic storage device exceeding the number. The distance between the two shield layers made of a soft magnetic material is preferably 0.12 μm or more from the viewpoint of easiness in working.

The thickness t of the magnetic layer of the magnetic recording medium having the above-described configuration and the residual magnetic flux density Br measured by applying a magnetic field in the direction of travel of the magnetic head relative to the magnetic recording medium during recording are measured. The product Br × t is not less than 3.2 mA (40 gauss / micron) and not more than 9.6 mA (120 gauss / micron) because Br × t is 3.2 mA (40 gauss / micron) for a long time after recording. , The danger of reproducing erroneous information increases, and if it exceeds 9.6 mA (120 gauss / micron), overwriting during recording becomes difficult.

Further, by forming at least two underlayers of the magnetic recording medium, the crystal orientation of the magnetic layer can be controlled. By forming this multilayer underlayer, the influence of atomic diffusion from the underlayer to the magnetic layer can be greatly reduced, and at the same time, the crystallinity of the underlayer close to the magnetic layer can be improved, and the adhesion between the magnetic layer and the underlayer can be improved. It becomes strong, and high sliding resistance is obtained. Further, since the surface of the underlayer close to the magnetic layer does not have a periodic arrangement of atoms over a long distance, the crystal grains of the magnetic layer formed thereon can be refined and the crystal orientation can be controlled. Become. This makes it possible to reduce the average grain size of the crystals constituting the magnetic layer to 15
It can be controlled to a fine size of nm or less, and at the same time, the direction of the axis of easy magnetization can be controlled in a direction parallel to the film surface suitable for in-plane magnetic recording.

A magnetoresistive head used in the magnetic storage device according to the present invention includes a plurality of conductive magnetic layers which generate a large resistance change when their magnetization directions are relatively changed by an external magnetic field. The magnetoresistive sensor includes a conductive nonmagnetic layer disposed between the conductive magnetic layers. It is 300 to use such a reproducing head.
It is used to stably reproduce a signal recorded at the highest linear recording density exceeding kFCI and obtain a signal output.

Further, the magnetoresistive head has an air bearing surface rail area of 1.25 mm ² or less and a mass of 2 mm.
The present invention is attained by being formed on a magnetic head slider of not more than mg. The reason why the area of the air bearing surface rail is 1.25 mm ² or less is to reduce the probability of colliding with the above-mentioned projections and, at the same time, reduce the mass to 2 mg or less, thereby improving the impact resistance reliability. This makes it possible to achieve both a recording density of 5 gigabits or more per square inch and high impact resistance.

Next, an embodiment of the present invention will be described in detail. FIG. 1 shows an example of an embodiment of the present invention.

[Embodiment 1] N was placed on an aluminum alloy substrate (outer diameter 95 mm, inner diameter 25 mm, thickness 0.8 mm).
The substrate 1 on which the i-P plating has been performed is subjected to texturing, and processed so that Ra = 2 nm and Rp = 15 nm (Ra and Rp are indices representing roughness). 15n height in the range of .5mm
m, a projection having a diameter of 3.5 μm and an interval of 10 μm were formed and sufficiently washed.

This was converted to 5.3 × 10E-5Pa (4.0 × 10E-5Pa).
10E-7 Torr). First, the substrate was transferred to a heating chamber in a vacuum layer, and the substrate was heated to 260 ° C. by an IR heater (infrared heater). Subsequently, the substrate is transferred to a base layer forming chamber, and an Ar atmosphere of about 0.
Under a condition of 8 Pa (6 mTorr), Cr-10 at. % Mo-7.5
at. % Ti alloy underlayer 2 was formed to a thickness of 30 nm.

Subsequently, the wafer is transferred to a magnetic recording layer forming chamber,
Under a condition of an atmosphere of about 0.9 Pa (7 mTorr), Co-20 at.
% Cr-4 at. % Ta-8 at. % Pt alloy layer 3 (forming a magnetic layer) was formed to a thickness of 22 nm. This Cr-1
0 at. % Mo-7.5 at. % Ti alloy underlayer 2, C
o-20 at. % Cr-4 at. % Ta-8 at. % P
Using the substrate formed up to the t alloy layer 3, a protective film layer mainly composed of carbon according to the present invention described below was formed.

The substrate 1 is made of an Al--Mg alloy substrate obtained by electroless plating of Ni--P, as well as a ceramic or glass glazing made of chemically strengthened aluminosilicate, soda lime glass, silicon, borosilicate glass, or the like. A rigid substrate made of applied ceramics or the like can be used.

The underlayer 2 is used as an underlayer that controls the crystal orientation of the underlayer formed thereon. As the underlayer, a nonmagnetic Cr— layer that forms an irregular solid solution that can be oriented (100) with good crystal matching with the magnetic layer is used.
V, Cr-Ti, Cr-Mo, Cr-Si, Cr-Mo
A thin film of a Cr-based alloy such as a -Ti alloy can also be used. Further, when 0.5% to 50% by volume of nitrogen was simultaneously added to a discharge gas used for sputtering to form an underlayer, crystal grains of the underlayer were refined. As a result, the crystal grains of the magnetic layer formed continuously were also refined, and the medium noise could be reduced.

The magnetic layer 3 is made of Co—Cr—Ta—P
It is possible to use not only a t-alloy but also a multi-component alloy containing Co as a main component, containing platinum to increase coercive force, and further adding Cr, Ta, SiO ₂ , Nb, etc. to reduce medium noise. it can. In particular, Ta, Nb, V, Ti
Is preferred because the melting point of the target decreases and the composition separation of the magnetic layer containing Cr easily proceeds.

In a Co-based alloy system to which Pt, Ni or Mn is added, the decrease in magnetic anisotropy energy is small compared to other added elements, and it is practical. Specifically, Co-Cr
In addition to -Pt, Co-Cr-Pt-Ta, Co-Cr-
_{Pt-SiO 2, Co-Cr} -Pt-Mn, Co-Cr
-Nb-Pt, Co-Cr-V-Pt, Co-Cr-T
i-Pt, Co-Cr-Nb-Ta-Pt, Co-Pt
It can be used -ni-SiO ₂ or the like of the alloy. Regarding the magnetism of the Co alloy layer that forms the ferromagnetic portion, the solid solution amount of Cr is 5 to 10 at. %, The solid solution amount of Ta is about 2 at. %, And by forming the Co alloy magnetic layer in excess of these solid solution amounts, magnetic separation in the magnetic layer progresses and media noise is reduced.

As a practical composition, for example, Co-2
0 at. % Cr-4 at. % Ta-8 at. % Pt alloy, Co-22 at. % Cr-20 at. % Pt alloy,
Co-15at. % Cr-8 at. % Pt-20mol
% SiO ₂ alloy, Co-17 at. % Cr-12 at.
% Pt-5 at. % Mn alloy, Co-17 at. % Cr
-5 at. % Nb-10 at. % Pt alloy, Co-20
at. % Cr-5 at. % V-12 at. % Pt alloy, Co-20 at. % Cr-10 at. % V-15a
t. % Pt alloy, Co-15 at. % Cr-5 at. %
Nb-5 at. % Ta-20 at. % Pt alloy or the like can be used.

Here, in (1) of FIG. 1, the left side of the figure represents the inner peripheral side of the magnetic disk, a raised area exists and is a CSS area, and the right side of the figure represents the outer peripheral side of the disk. It is a data area.

The substrate was transferred to the protective film layer forming chamber 21 by the ion beam method shown in FIG. 2 without being taken out of the vacuum layer. This protective film layer forming chamber 21 is provided with a hot filament 22
And an ion gun comprising an anode 23 and a grid 24 disposed in front of the hot filament. Further, a film is positively deposited only in an area where the magnetic head within a radius of 20.7 mm on the substrate comes into contact with the magnetic head when the magnetic head is activated and / or stopped, provided with the vapor-deposited particle shield 25, The structure is extremely difficult to deposit a film. That is, a film is formed only in the CSS area on the inner peripheral portion of the disk by the ion beam method. While evacuating this protective film layer forming chamber 21 with a turbo molecular pump, Ar gas was introduced from the rear of the anode at 15 sccm (Standard Cubi).
c centimeter per minutes)
And ethylene (C ₂ H ₄ ) gas were introduced through a 15 sccm mass flow controller. The pressure at this time was about 0.5 Pa (4 mTorr) using a Baratron gauge.

Next, 350 mA was applied to the hot filament of the ion gun located on both sides of the substrate, and DC + was applied to the anode.
A voltage of 120 V was applied to induce plasma. Then, -530 V was applied to the grid to extract ions. Further, a pulse bias of -80 V and 3 kHz was applied to the substrate. At this time, the anode current was 500 mA, and the bias current of the substrate was 120 mA. By this so-called ion beam deposition method (IBD), Co-Cr
A DLC protective film layer 4 mainly composed of carbon and hydrogen within a range of a radius of 20.7 mm above the Ta-Pt alloy layer 3 by 5n;
m was formed. The deposition rate of the film at this time is 1.0 nm /
s.

Next, this substrate was transferred to the protective film forming chamber 31 by the sputtering method shown in FIG. While evacuating the protective layer forming chamber 31 in turbomolecular pumps, the N ₂ 30% and H ₂ 6.0% mixed gas was 24sccm introduced through a mass flow controller to Ar. The pressure at this time is about 1 Pa (8
mTorr). Next, DC 1000 W was applied to the graphite sintered target fixed to the cathode located on both sides of the substrate to induce plasma. At this time, the discharge current was about 1.5 A, and the discharge voltage was about 670 V. By this so-called reactive sputtering method, an amorphous carbon protective film layer 5 containing carbon and nitrogen as main components and containing hydrogen was formed to a thickness of 6 nm on almost the entire surface of the substrate having the protective film layer 4. The deposition rate of the film at this time is 0.
It was 8 nm / s.

As a result, as shown in FIG. 1B, the protective film layer has a two-layer structure of a DLC layer and an amorphous carbon layer inside a radius of 20.7 mm, and has a total thickness of 11 n.
m, outside the radius of 20.7 mm, only the amorphous carbon layer has a thickness of 6 nm. The substrate was removed from the vacuum layer and allowed to cool to room temperature.

A plurality of discs were prepared by the above-described method, and some discs were subjected to analysis of the protective film layer. Some discs were subjected to tape cleaning, and then a fluorocarbon-based lubricant was provided in a thickness of about 2 nm, and a floating check was performed. After performing the test, a sliding test using a single plate or a reliability test was conducted by assembling the magnetic disk device.

The area from the contact start and stop (CSS) area of the protective film layer of the disk manufactured by the above method to the so-called data area where there is no regular contact with the magnetic head in an area other than performing the CSS. The film thickness was measured at a pitch of 0.1 mm using an ellipsometer. As a result, the transition region from 90% of the thickness of the CSS region, ie, 9.9 nm, to 110% of the thickness of the data area, ie, 6.6 nm, was 2.6 mm.

That is, referring to (3) of FIG. 1, the formation of the DLC layer in the CSS area is performed in a vertical state as schematically shown in (2) of FIG. 1 at the boundary with the data area. Is practically impossible in practice, and the layers are laminated with a certain degree of gentleness. As a numerical value representing the lamination state at the boundary, the thickness A of the CSS area
% Of the disk radius R1 at a point of 110% of the thickness B of the data area (R1).
2-R1), that is, the smaller the transition region, the steeper the boundary surface. It can be said that the difference of 5 or less is an index indicating steepness. In order to secure strength in the CSS area, it is preferable that A / B is 1.3 or more.

The reason why the transition region between the CSS area and the data area is smaller than the index 5 in the first embodiment is that the DLC layer is formed only in the CSS area using the ion beam method. . It was found that in the sputtering method, an ion wraparound phenomenon appeared, and the steepness at the film formation boundary was inferior to that of the ion beam method.

Further, Raman spectroscopy was performed to examine the structure of the protective film layer of the disk manufactured by the above method. For simplicity, a disk without the protective film layer 4 and a disk without the protective film layer 5 were used. As an analyzer, an Ar laser (514.5 nm) and a measurement wave number of 100 were used using a Raman spectroscopic analyzer 2010 manufactured by Lennyshaw.
0 to 1800 or 1000 to 2300 / cm. As a result, as shown in FIG.
A typical DLC film has a characteristic of having only one peak near 50 Kaiser (1550 (1 / cm) on the horizontal axis in FIG. 4) and not having a very large peak near 1350 Kaiser. It was confirmed that it was.

As shown in FIG. 5, the protective film layer 5
A typical amorphous carbon waveform having a broad peak from 900 to 1800 / cm is shown.
In the vicinity of 230 / cm, there is a vibration peak of C = N terminal bond-C≡N. In addition, since the background has a gentle slope from 900 to 2300 / cm, it was confirmed that the amorphous carbon was rich in nitrogen and also contained hydrogen.

On the other hand, the disk provided with the lubricant was mounted on a contact start and stop (CSS) evaluation device and tested. 10 disks with 7500 rpm
r. p. When the test was performed 50000 times at m, the test was completed without crashing all 10 sheets, and thereafter the surface was carefully observed with a microscope and visually with oblique light, but no damage to the disc was observed. As a result, it has been proved that the magnetic recording medium according to the present invention has sufficient sliding reliability when the thickness of the protective film in the region where the magnetic head performs CSS is 11 nm.

Next, in a region other than the case where CSS is performed, a random seek of the magnetic head is performed at 7500 rpm in a so-called data area (radius 21 mm to 46 mm) where there is no regular contact with the magnetic head. p. Then, 0.1 g of alumina particles having an average particle diameter of 0.1 μm were put on the disk while the particles were sought for 120 seconds, and then the surface was observed with a microscope and visually with oblique light. As a result, although the surface of the protective film was slightly scratched, the protective film was broken, that is, a so-called crash did not occur. As a result, it has been proved that the magnetic recording medium according to the present invention can obtain sufficient sliding reliability even though the thickness of the protective film layer in the data area is as thin as 6 nm.

[Embodiment 2] N was placed on an aluminum alloy substrate (outer diameter 95 mm, inner diameter 25 mm, thickness 0.8 mm).
After texturing is applied to the substrate 1 on which the i-P plating has been performed, Ra = 2 nm and Rp = 15 nm (Ra and Rp are indices representing roughness), and then a radius of 18.0-20. 15 nm height in a range of 5 mm,
Protrusions having a diameter of 3.5 μm and an interval of 10 μm were formed and sufficiently washed.

This was converted to 5.3 × 10E-5Pa (4.0 × 10E-5Pa).
10E-7 Torr). First, the substrate was transferred to a heating chamber in a vacuum layer, and the substrate was heated to 260 ° C. by an IR heater (infrared heater). Subsequently, the substrate is transferred to a base layer forming chamber, and an Ar atmosphere of about 0.
Under a condition of 8 Pa (6 mTorr), Cr-10 at. % Mo-7.5
at. % Ti alloy underlayer 2 was formed to a thickness of 30 nm.

Subsequently, it is transported to the magnetic recording layer forming chamber and
Under a condition of an atmosphere of about 0.9 Pa (7 mTorr), Co-20 at.
% Cr-4 at. % Ta-8 at. % Pt alloy layer 3 (forming a magnetic layer) was formed to a thickness of 22 nm. This Cr-1
0 at. % Mo-7.5 at. % Ti alloy underlayer 2, C
o-20 at. % Cr-4 at. % Ta-8 at. % P
Using the substrate formed up to the t alloy layer 3, a protective film layer mainly composed of carbon according to the present invention described below was formed.

The substrate 1 is made of an Al—Mg alloy substrate obtained by electroless plating Ni—P, as well as a ceramic or glass glazing made of chemically strengthened aluminosilicate, soda lime glass, silicon, borosilicate glass, or the like. A rigid substrate made of applied ceramics or the like can be used.

The underlayer 2 is used as an underlayer that controls the crystal orientation of the underlayer formed thereon. As the underlayer, a nonmagnetic Cr— layer that forms an irregular solid solution that can be oriented (100) with good crystal matching with the magnetic layer is used.
V, Cr-Ti, Cr-Mo, Cr-Si, Cr-Mo
A thin film of a Cr-based alloy such as a -Ti alloy can also be used. Further, when 0.5% to 50% by volume of nitrogen was simultaneously added to a discharge gas used for sputtering to form an underlayer, crystal grains of the underlayer were refined. As a result, the crystal grains of the magnetic layer formed continuously were also refined, and the medium noise could be reduced.

The magnetic layer 3 is made of Co—Cr—Ta—P
It is possible to use not only a t-alloy but also a multi-component alloy containing Co as a main component, containing platinum to increase coercive force, and further adding Cr, Ta, SiO ₂ , Nb, etc. to reduce medium noise. it can. In particular, the addition of Ta, Nb, V, and Ti is preferable because the melting point of the target decreases and the composition separation of the Cr-containing magnetic layer easily proceeds.

In a Co-based alloy system to which Pt, Ni or Mn is added, the decrease in magnetic anisotropy energy is small compared to other added elements, and it is practical. Specifically, Co-Cr
In addition to -Pt, Co-Cr-Pt-Ta, Co-Cr-
_{Pt-SiO 2, Co-Cr} -Pt-Mn, Co-Cr
-Nb-Pt, Co-Cr-V-Pt, Co-Cr-T
i-Pt, Co-Cr-Nb-Ta-Pt, Co-Pt
It can be used -ni-SiO ₂ or the like of the alloy. Regarding the magnetism of the Co alloy layer that forms the ferromagnetic portion, the solid solution amount of Cr is 5 to 10 at. %, The solid solution amount of Ta is about 2 at. %, And by forming the Co alloy magnetic layer in excess of these solid solution amounts, magnetic separation in the magnetic layer progresses and media noise is reduced.

As a practical composition, for example, Co-2
0 at. % Cr-4 at. % Ta-8 at. % Pt alloy, Co-22 at. % Cr-20 at. % Pt alloy,
Co-15at. % Cr-8 at. % Pt-20mol
% SiO ₂ alloy, Co-17 at. % Cr-12 at.
% Pt-5 at. % Mn alloy, Co-17 at. % Cr
-5 at. % Nb-10 at. % Pt alloy, Co-20
at. % Cr-5 at. % V-12 at. % Pt alloy, Co-20 at. % Cr-10 at. % V-15a
t. % Pt alloy, Co-15 at. % Cr-5 at.
% Nb-5 at. % Ta-20 at. % Pt alloy or the like can be used.

FIG. 3 shows the state in which the substrate is not taken out of the vacuum layer.
Was transported to the protective film layer forming chamber 31 by the sputtering method shown in FIG. While evacuating the protective layer forming chamber 31 in turbomolecular pumps, the N ₂ 30% H2 in Ar 6.
0% mixed gas through mass flow controller 2
4 sccm was introduced. The pressure at this time was about 1 Pa (8 mTorr) with a Baratron gauge. Next, DC 1000 W was applied to the graphite sintered target fixed to the cathode located on both sides of the substrate to induce plasma. At this time, the discharge current was about 1.5 A, and the discharge voltage was about 670 V. By this reactive sputtering method, an amorphous carbon protective film layer 5 containing carbon and nitrogen as main components and containing hydrogen is formed on the Co—Cr—Ta—Pt alloy layer 3 to a thickness of 6 nm over the entire CSS area and data area. Formed. At this time, the deposition rate of the film was 0.8 nm / s.

Next, this substrate was transferred to the protective film layer forming chamber 21 by the ion beam method as shown in FIG. The protective film layer forming chamber 21 includes a hot filament 22 and an anode 2.
3 and an ion gun comprising a grid 24 disposed in front of the hot filament. In addition, a vapor deposition particle shield 25 as shown in FIG.
The film is positively deposited only in a region where the magnetic heads contact when the magnetic head is activated and / or stopped, and the film is extremely unlikely to deposit outside of 20.7 mm. While evacuating the protective film layer forming chamber 21 with a turbo molecular pump, Ar gas and ethylene (C ₂ H ₄ ) gas were introduced from the back of the anode through a mass flow controller at 15 sccm and 15 sccm, respectively. The pressure at this time was about 0.5 Pa (4 mTorr) using a Baratron gauge.

Next, 350 mA was applied to the hot filament of the ion gun located on both sides of the substrate, and DC + was applied to the anode.
A voltage of 120 V was applied to induce plasma. Then, -530 V was applied to the grid to extract ions. Further, a pulse bias of -80 V and 3 kHz was applied to the substrate. At this time, the anode current was 500 mA, and the bias current of the substrate was 120 mA. By this so-called ion beam deposition method (IBD), the protective film layer 5 is formed.
A DLC protective film layer 4 containing carbon and hydrogen as main components was formed to a thickness of 5 nm within a radius of 20.7 mm above. That is, an amorphous carbon protective film layer 5 is formed on the magnetic layer and a DLC layer 4 is formed on the protective film layer 5 as a CSS area on the inner peripheral side of the disk. At this time, the deposition rate of the film was 1.0 nm / s. As a result, the protective film layer has a two-layer structure of an amorphous carbon layer and a DLC layer inside the radius of 20.7 mm, and has a total thickness of 11 n.
m, outside the radius of 20.7 mm, only the amorphous carbon layer has a thickness of 6 nm. The substrate was removed from the vacuum layer and allowed to cool to room temperature.

A plurality of disks were prepared by the above-mentioned method, some of them were subjected to analysis of the protective film layer, and some of them were subjected to tape cleaning, then provided with a fluorocarbon-based lubricant of about 2 nm in thickness, and checked for flying height. After performing the test, a sliding test using a single plate or a reliability test was conducted by assembling the magnetic disk device.

The area from the contact start and stop (CSS) area of the protective film layer of the disk manufactured by the above method to the so-called data area where there is no regular contact with the magnetic head in an area other than performing the CSS. The film thickness was measured at a pitch of 0.1 mm using an ellipsometer. As a result, the transition region from 90% of the thickness of the CSS region, ie, 9.9 nm, to 110% of the thickness of the data area, ie, 6.6 nm, was 2.4 mm.

Further, Raman spectroscopy was performed to examine the structure of the protective film layer of the disk manufactured by the above method. For simplicity, a disk without the protective film layer 4 and a disk without the protective film layer 5 were used. As an analyzer, an Ar laser (514.5 nm) and a measurement wave number of 100 were used using a Raman spectroscopic analyzer 2010 manufactured by Lennyshaw.
0 to 1800 or 1000 to 2300 / cm.

As a result, as shown in FIG. 4, the protective film layer 4 has 1550 Kaiser (1550 (1 / c on the horizontal axis in FIG. 4).
m) has only one peak near 1350 and 1350
By exhibiting a characteristic having no such a large peak near Kaiser, it was confirmed that the film was a typical DLC film.

As shown in FIG. 5, the protective film layer 5
A typical amorphous carbon waveform having a broad peak from 900 to 1800 / cm is shown.
In the vicinity of 230 / cm, there is a vibration peak of C = N terminal bond-C≡N. In addition, since the background has a gentle slope from 900 to 2300 / cm, it was confirmed that the amorphous carbon was rich in nitrogen and also contained hydrogen.

On the other hand, the disk provided with the lubricant was mounted on a contact start and stop (CSS) evaluation device and tested. 10 disks with 7500 rpm
r. p. When the test was performed 50000 times at m, the test was completed without crashing all 10 sheets, and thereafter the surface was carefully observed with a microscope and visually with oblique light, but no damage to the disc was observed. As a result, it has been proved that the magnetic recording medium according to the present invention has sufficient sliding reliability when the thickness of the protective film in the region where the magnetic head performs CSS is 11 nm.

Next, in a so-called data area (radius of 21 mm to 46 mm) where there is no regular contact with the magnetic head in an area other than the area where CSS is performed, a random seek of the magnetic head is performed at 7500 rpm. p. Then, 0.1 g of alumina particles having an average particle diameter of 0.1 μm were put on the disk while the particles were sought for 120 seconds, and then the surface was observed with a microscope and visually with oblique light. As a result, although the surface of the protective film was slightly scratched, the so-called crash that destroyed the protective film did not occur. As a result,
It has been proved that the magnetic recording medium according to the present invention can obtain sufficient sliding reliability even though the thickness of the protective film layer in the data area is as thin as 6 nm.

[Comparative Example 1] A disk was manufactured by substantially the same manufacturing method as in "Embodiment 1" except that the DLC protective film layer 4 was not provided. That is, almost the entire surface of the disk is protected by the amorphous carbon protective film layer 5 alone.
Ten disks provided with the lubricant were mounted on a (CSS) evaluation device in the same manner as in the first embodiment, and a test was performed. As a result, all 10 disks crashed less than 1,000 times. Further, when a seek test and surface observation were performed using the other 10 sheets in the same manner as in Embodiment 1, although the surface of the protective film was slightly scratched, a so-called crash that destroyed the protective film did not occur. Did not. As a result, it was found that the disk manufactured by the method of Comparative Example 1 had sufficient sliding reliability in the data area but did not have sufficient sliding reliability in the area where CSS was performed.

[Comparative Example 2] A substantially entire surface of the disk was covered with a DLC protective film without providing the amorphous carbon protective film layer 5 and using a vapor deposition particle shield when providing the DLC protective film layer 4. At this time, a protective film layer 4 was formed to a thickness of 5 nm. Except for the above, a disk was manufactured by substantially the same manufacturing method as in "Embodiment 1". Ten disks provided with the lubricant were mounted on a (CSS) evaluation device in the same manner as in the first embodiment, and a test was performed.

As a result, all the ten disks were 700
It crashed in less than 0 times. In addition, another 10
When a seek test and surface observation were performed using the same method as in the first embodiment, although the surface of the protective film was slightly scratched, the so-called crash that destroyed the protective film layer did not occur. As a result, it was found that the disk manufactured by the method of Comparative Example 2 had sufficient sliding reliability in the data area, but did not have sufficient sliding reliability in the CSS area.

Comparative Example 3 The protective film forming chamber 21 had the same sputtering gun as the protective film forming chamber 31. Outside the radius of 20.7 mm, the shield is not removed so that sputtered particles are less likely to adhere.
When the protective film layer 4 is provided in the protective film forming chamber 21,
A gas containing 30% of N ₂ and 6.0% of H ₂ mixed with Ar was introduced at 24 sccm through a mass flow controller. The pressure at this time is about 1.0 Pa (8.
0 mTorr).

Next, DC1 was applied to a graphite sintered target fixed to cathodes located on both sides of the substrate.
000 W was applied to induce plasma. At this time, the discharge current was about 1.5 A, and the discharge voltage was about 670 V. By this so-called reactive sputtering method, Co-C
A protective film layer 4 containing a large amount of carbon, nitrogen, and hydrogen is formed on the r-Ta-Pt alloy layer 3 within a radius of 20.7 mm within 5n
m was formed. The deposition rate of the film at this time is 0.8 nm /
s. As described above, a disk was manufactured by substantially the same manufacturing method as that of “Embodiment 1” except for the method of providing the protective film layer 4.

The area from the contact start and stop (CSS) area of the protective film layer of the disk manufactured by the above method to the so-called data area which does not normally contact with the magnetic head in the area other than performing the CSS. The film thickness was measured at a pitch of 0.1 mm using an ellipsometer. As a result, the transition region from 90% of the thickness of the CSS region, ie, 9.9 nm, to 110% of the thickness of the data area, ie, 6.6 nm, was 8.7 mm.

As a result, when the protective film layer 4 is formed by using the reactive sputtering method, even if a shield similar to that used by the ion beam deposition method is provided, the CSS may be used.
It was found that the film thickness of the area could not be sharply raised at a short distance, the uniformity of the film thickness of the data area could not be secured, and the film thickness of the CSS area could not be secured as desired. Ten disks provided with the lubricant were mounted on a (CSS) evaluation device in the same manner as in the first embodiment, and a test was performed.

As a result, all of the 10 disks
It crashed in less than 00 times. And another one
When a seek test and surface observation were carried out using the zero sheet in the same manner as in Embodiment 1, although the surface of the protective film had some very shallow scratches, no so-called crash that destroyed the protective film layer was found. As a result, it was found that the disk manufactured by the method of Comparative Example 3 had sufficient sliding reliability in the data area, but did not have sufficient sliding reliability in the CSS area.

The disk described in "Embodiment 3", "Embodiment 1" or "Embodiment 2" was subjected to 50,000 CS
As a result of the S sliding resistance test, the thickness of the magnetic film was reduced to 15 n
In any of the magnetic recording media of m, 17 nm, and 21 nm, the magnetic recording medium and the magnetic head were not broken, and good sliding reliability was obtained.

By reducing the thickness of the magnetic layer, the product Br × t of the thickness t of the magnetic layer and the residual magnetic flux density Br was greatly reduced. The in-plane coercive force Hc is approximately 176 kA / m to 256 kA / m, the coercive force squareness ratio S ^* is about 0.7 from 0.74 to 0.65, and the squareness ratio S is 0.78 to 0.7.
Met. These magnetic properties were measured at 25 ° C. using a vibrating sample magnetometer.

The electromagnetic conversion characteristics of these magnetic recording media were measured using a magnetic head in which the shield gap length Gs of the magnetoresistive read element (MR element) was 0.18 μm and the gap length of the write element was 0.3 μm. . The sense current of the MR element was 6 mA, and the write current Iw was 41 mA. By changing the rotation speed of the magnetic recording medium (magnetic disk medium) and changing the flying height of the head, the output half width PW50 of the isolated reproduction wave was measured by a digital oscilloscope (Tektronix TDS544A). The PW50 is smaller as the magnetic film is thinner and the flying height of the magnetic head is lower. When the magnetic film thickness is 15 nm and the flying height of the head is 25 nm, a small value of 240 nm is obtained.

The output at the maximum linear recording density of 360 kFCI measured by the spectrum analyzer was 1-2% of the output of the isolated reproduction wave at 10 kFCI measured by the digital oscilloscope. The output at the maximum linear recording density of 360 kFCI measured by the spectrum analyzer was obtained by integrating the output of the odd-order waveform until the output exceeded 100 MHz. Further, the 0-p output (SL
F) and the ratio SLF / Nd of integrated medium noise (Nd) when a signal of 360 kFCI was recorded was evaluated. here,
The flying height of the head is 25 nm, and Nd is 0.5 kFCI.
To 540 kFCI. In each medium, a high SLF / Nd ratio of 24 dB or more was obtained at a high recording density of 360 kFCI.

The magnetic disk medium 61, a drive unit 62 for driving the magnetic recording medium, a magnetic head 63 composed of a recording unit and a reproducing unit, and means for moving the magnetic head relative to the magnetic recording medium FIG. 6 shows a magnetic memory device having a signal input means to the magnetic head 64 and a recording / reproducing signal processing means 65 for reproducing an output signal from the magnetic head.

The reproducing section of the magnetic head is constituted by a magnetoresistive magnetic head. FIG. 7 shows a schematic perspective view of the magnetic head used for the measurement. This head is a composite type head having both an electromagnetic induction type head for recording and a magnetoresistive head for reproduction formed on a substrate 601. The recording head was composed of an upper recording magnetic pole 603 sandwiching a coil 602 and a lower recording magnetic pole / upper shield layer 604, and the gap length between the recording magnetic poles was 0.3 μm. Further, copper having a thickness of 3 μm was used for the coil. The reproducing head includes a magnetoresistive sensor 605 and electrode patterns 606 at both ends of the magnetoresistive sensor. Both magnetoresistive sensors have a lower recording magnetic pole / upper shield layer 604 and a lower shield layer 60 having a thickness of 1 μm.
7, and the shield interlayer distance is 0.20 μm. In FIG. 7, the gap layer between the recording magnetic poles and the gap layer between the shield layer and the magnetoresistive sensor are omitted.

FIG. 8 shows a sectional structure of the magnetoresistive sensor.
The signal detection region 701 of the magnetic sensor includes a lateral bias layer 702 and an isolation layer 7 on a gap layer 700 of aluminum oxide.
03, consisting of portions where the magnetoresistive ferromagnetic layers 704 are sequentially formed. The magnetoresistive ferromagnetic layer 704 has a thickness of 20 nm of Ni.
-Fe alloy was used. 25 nm for the lateral bias layer 702
Ni-Fe-Nb alloy was used, but Ni-Fe-Rh
Any ferromagnetic alloy having relatively high electric resistance and good soft magnetic properties may be used. The lateral bias layer 702 is formed by a magnetic field generated by a sense current flowing through the magnetoresistive ferromagnetic layer 704.
It is magnetized in an in-plane direction (lateral direction) perpendicular to the current, and applies a lateral bias magnetic field to the magnetoresistive ferromagnetic layer 704. As a result, a magnetic sensor showing a linear reproduction output with respect to the leakage magnetic field from the medium 61 is selected. Separation layer 70 that prevents shunting of sense current from magnetoresistive ferromagnetic layer 704
3 is made of Ta having a relatively high electric resistance, and has a thickness of 5n.
m.

At both ends of the signal detection region, there are tapered portions 705 processed into a tapered shape. Tapered part 705
Is composed of a permanent magnet layer 706 for turning the magnetoresistive ferromagnetic layer 704 into a single magnetic domain, and a pair of electrodes 606 formed thereon for extracting signals. The permanent magnet layer 706 needs to have a large coercive force and the magnetization direction does not easily change, and an alloy such as Co—Cr or Co—Cr—Pt is used.

A magnetic storage device shown in FIG. 6 was constructed by combining the magnetic recording medium described in “Embodiment 1” or “Embodiment 2” with the above-described head shown in FIG. As a result, in a levitation system having a magnetic levitation height hm of about 48 to 60 nm, a magnetic field is applied to the thickness t of the magnetic layer and the relative running direction of the magnetic head with respect to the magnetic recording medium during recording. If the product Br × t with the measured residual magnetic flux density Br exceeds 9.6 mA (120 gauss / micron), sufficient writing cannot be performed, and overwriting (overwriting characteristics deteriorates, especially output in a high linear recording density region) Also fell.

On the other hand, when Br × t is smaller than 3.2 mA (40 gauss / micron), a decrease in reproduction output is observed for 4 days at 70 ° C., depending on the composition or thickness of the recording layer of the medium. There was a case. Accordingly, a magnetic field is applied in the thickness t of the magnetic layer described in the magnetic recording medium described in the “Embodiment 1” and the “Embodiment 2” and in the direction of travel of the magnetic head relative to the magnetic recording medium during recording. Br × t with the residual magnetic flux density Br measured at 3.2 mA
(40 Gauss / micron) or more and 9.6 mA (120 Gauss / micron) or less, the magnetic storage device was configured.

When the magnetoresistive sensor of the magnetoresistive effect type magnetic head uses a head formed between two shield layers made of a soft magnetic material and separated from each other by a distance exceeding 0.2 μm. Has a maximum linear recording density of 250k
If the FCI was exceeded, sufficient reproduction output could not be obtained. The distance between the two shield layers made of a soft magnetic material is 0.12 μm.
If it was less than the above, it was not possible to easily form an element due to difficulty in processing. From these results, a magnetic storage device was configured using a head formed between two shield layers made of a soft magnetic material separated by a distance of 0.12 μm or more and 0.2 μm or less. With the magnetic storage device thus configured, a recording density of 5 gigabits per square inch or more could be realized.

[Fourth Embodiment] Instead of the magnetoresistive head used in the third embodiment, the magnetoresistive head 63 according to the third embodiment has the same structure as that of the third embodiment. The magnetoresistive sensor includes a plurality of conductive magnetic layers that generate a large resistance change when the direction relatively changes by an external magnetic field, and a conductive nonmagnetic layer disposed between the conductive magnetic layers. The magnetic storage device was configured with the same configuration as that of FIG. 6 except that a magnetic head was used.

FIG. 9 shows a sectional view of the sensor used. This sensor includes a 5 nm Ta buffer layer 801, a 7 nm first magnetic layer 802, a 1.5 nm copper intermediate layer 803, and a 3 nm second magnetic layer 80 on a gap layer 608.
4, 10 nm Fe-50 at. % Mn antiferromagnetic alloy layer 805 is sequentially formed. The first magnetic layer contains Ni-20 at. % Fe alloy was used, and cobalt was used for the second magnetic layer 804. Due to the exchange magnetic field from the antiferromagnetic layer 805, the magnetization of the second magnetic layer 804 is fixed in one direction. On the other hand, the second magnetic layer 804
Since the direction of magnetization of the first magnetic layer 802 in contact with the first magnetic layer 802 via the nonmagnetic layer 803 changes due to the leakage magnetic field from the magnetic recording medium 61, a change in resistance occurs.

The resistance change caused by the change in the relative directions of the magnetizations of the two magnetic layers is called a spin valve effect. In this embodiment, a spin-valve magnetic head utilizing this effect is used as a reproducing head. Tapered part 70
Reference numeral 5 has the same configuration as the magnetic sensor of the “third embodiment”.

The Br × t of the magnetic recording medium used for the measurement was 3, 3.2, 4, 6, 8, 10, 12, 14 mA. When Br × t was set to 3 mA (37.5 gauss microns), the reproduction signal significantly decreased with time, and it was difficult to obtain a practically preferable coercive force. When Br × t exceeds 12 mA (150 gauss microns), the output of 2F is large, but the output resolution tends to decrease.

When such a spin-valve reproducing head is used, as described in the third embodiment, 360 k
A signal recorded at the highest linear recording density exceeding FCI was reproduced stably and a signal output was obtained.

The head shown here is the third embodiment.
And the magnetoresistive effect type magnetic head was formed on a magnetic head slider having an air bearing surface rail area of 1.4 mm ² or less and a mass of 2 mg or less. The reason why the area of the air bearing surface rail is 1.4 mm ² or less is that the probability of colliding with the above-mentioned projection is reduced, and at the same time, the mass is 2 mg or less, so that the impact resistance can be improved. As a result, both high recording density and high impact resistance can be achieved, and a mean time between failures (MTBF) of 300,000 hours or more can be realized at a recording density of 5 gigabits per square inch or more.

Embodiment 5 N was placed on an aluminum alloy substrate (outer diameter 95 mm, inner diameter 25 mm, thickness 0.8 mm).
After texturing processing was performed on the substrate 1 on which the i-P plating was performed to obtain Ra = 2 nm and Rp = 15 nm (Ra and Rp are indices indicating roughness), the substrate 1 was sufficiently washed. This is 5.3 × 10E-5Pa (4.0 × 10E-
7 Torr). First, the substrate was transferred to a heating chamber in a vacuum layer, and the substrate was heated to 260 ° C. by an IR heater (infrared heater).

Subsequently, the substrate was transported to the underlayer forming chamber, and was subjected to DC magnetron sputtering under a condition of about 0.8 Pa (6 mTorr) in an Ar atmosphere to obtain Cr-10 at. % Mo
-7.5 at. % Ti alloy underlayer 2 was formed to a thickness of 30 nm. Subsequently, the substrate is transported to a magnetic recording layer forming chamber and subjected to Co-20 at. By a DC magnetron sputtering method under an Ar atmosphere of about 0.9 Pa (7 mTorr). % Cr-
4 at. % Ta-8 at. % Pt alloy layer 3 (forming a magnetic layer) was formed to a thickness of 22 nm.

This Cr-10at. % Mo-7.5a
t. % Ti alloy underlayer 2, Co-20 at. % Cr-4
at. % Ta-8 at. Using the substrate formed up to the% Pt alloy layer 3, a protective film layer mainly containing carbon according to the present invention described below was formed.

The substrate 1 may be made of an Al—Mg alloy substrate obtained by electroless plating of Ni—P, as well as a ceramic or glass glazing made of chemically strengthened aluminosilicate, soda lime glass, silicon, borosilicate glass, or the like. A rigid substrate made of applied ceramics or the like can be used.

The underlayer 2 is used as an underlayer that controls the crystal orientation of the underlayer formed thereon. As the underlayer, a nonmagnetic Cr— layer that forms an irregular solid solution that can be oriented (100) with good crystal matching with the magnetic layer is used.
V, Cr-Ti, Cr-Mo, Cr-Si, Cr-Mo
A thin film of a Cr-based alloy such as a -Ti alloy can also be used. Further, when 0.5% to 50% by volume of nitrogen was simultaneously added to a discharge gas used for sputtering to form an underlayer, crystal grains of the underlayer were refined. As a result, the crystal grains of the magnetic layer formed continuously were also refined, and the medium noise could be reduced.

The magnetic layer 3 is made of Co—Cr—Ta—P
It is possible to use not only the t alloy but also a multi-element alloy containing Co as a main component, containing platinum for increasing the coercive force, and further adding Cr, Ta, SiO2, Nb, etc. for reducing the medium noise. . In particular, the addition of Ta, Nb, V, and Ti is preferable because the melting point of the target decreases and the composition separation of the Cr-containing magnetic layer easily proceeds.

In a Co-based alloy to which Pt, Ni or Mn is added, the magnetic anisotropy energy is practically less reduced than other added elements. Specifically, Co-Cr
In addition to -Pt, Co-Cr-Pt-Ta, Co-Cr-
_{Pt-SiO 2, Co-Cr} -Pt-Mn, Co-Cr
-Nb-Pt, Co-Cr-V-Pt, Co-Cr-T
i-Pt, Co-Cr-Nb-Ta-Pt, Co-Pt
It can be used -ni-SiO ₂ or the like of the alloy. Regarding the magnetism of the Co alloy layer that forms the ferromagnetic portion, the solid solution amount of Cr is 5 to 10 at. %, The solid solution amount of Ta is about 2 at. %, And by forming the Co alloy magnetic layer in excess of these solid solution amounts, magnetic separation in the magnetic layer proceeds and medium noise is reduced.

As a practical composition, for example, Co-2
0 at. % Cr-4 at. % Ta-8 at. % Pt alloy, Co-22 at. % Cr-20 at. % Pt alloy,
Co-15at. % Cr-8 at. % Pt-20mol
% SiO ₂ alloy, Co-17 at. % Cr-12 at.
% Pt-5 at. % Mn alloy, Co-17 at. % Cr
-5 at. % Nb-10 at. % Pt alloy, Co-20
at. % Cr-5 at. % V-12 at. % Pt alloy,
Co-20 at. % Cr-10 at. % V-15 at.
% Pt alloy, Co-15 at. % Cr-5 at. % Nb
-5 at. % Ta-20 at. % Pt alloy or the like can be used.

FIG. 3 shows a state in which the substrate is not taken out of the vacuum layer.
Was transferred to the protective film layer forming chamber 31 shown in FIG. While evacuating this protective film layer forming chamber 31 with a turbo molecular pump,
A gas containing 30% of N ₂ and 6.0% of H ₂ mixed with r was introduced at 24 sccm through a mass flow controller. The pressure at this time is about 1 Pa (8 mTorr) using a Baratron gauge.
r).

Next, DC1 was applied to a graphite sintered target fixed to cathodes located on both sides of the substrate.
000 W was applied to induce plasma. At this time, the discharge current was about 1.5 A, and the discharge voltage was about 670 V. By this so-called reactive sputtering method, Co-C
On the r-Ta-Pt alloy layer 3, an amorphous carbon protective film layer 5 containing carbon and nitrogen as main components and containing hydrogen was formed to a thickness of 6 nm. At this time, the deposition rate of the film was 0.8 nm / s.

Next, the substrate was transferred to the protective film layer forming chamber 21. The protective film layer forming chamber 21 is an ion gun including a hot filament 22, an anode 23, and a grid 24 disposed in front of the hot filament. Further, a vapor deposition particle shield 25 as shown in FIG. 10 is provided, and a film is positively deposited only on a region outside a radius of 45.5 mm on the substrate, and a film is extremely deposited inside a region of 45.5 mm. The structure is difficult. While evacuating the protective film layer forming chamber 21 with a turbo molecular pump, 15 sccm of Ar gas and 15 sccm of ethylene (C ₂ H ₄ ) gas are supplied from the back of the anode.
Introduced via mass flow controller. The pressure at this time is about 0.5 Pa (4 mTorr) using a Baratron gauge.
Met.

Next, 350 mA was applied to the hot filament of the ion gun located on both sides of the substrate, and DC + was applied to the anode.
A voltage of 120 V was applied to induce plasma. Then, -530 V was applied to the grid to extract ions. Further, a pulse bias of -80 V and 3 kHz was applied to the substrate. At this time, the anode current was 500 mA, and the bias current of the substrate was 120 mA. By this so-called ion beam deposition method (IBD), the protective film layer 4 is formed.
A DLC protective film layer 5 containing carbon and hydrogen as main components was formed to a thickness of 5 nm outside the radius of 45.5 mm above. At this time, the deposition rate of the film was 1.0 nm / s. As a result, the protective film layer has a two-layer structure of an amorphous carbon layer and a DLC layer outside the radius of 45.5 mm, and has a total thickness of 11 nm, and inside the radius of 45.5 mm only the amorphous carbon layer and has a thickness of 6 nm. The substrate was removed from the vacuum layer and allowed to cool to room temperature.

A plurality of discs were prepared by the above-mentioned method, and some discs were subjected to analysis of the protective film layer, and some discs were subjected to tape cleaning, and then a fluorocarbon-based lubricant was provided in a thickness of about 2 nm, and a floating check was performed. After performing the test, a sliding test using a single plate or a reliability test was conducted by assembling the magnetic disk device.

An ellipsometer is used to measure the area from the ramp load area of the protective film layer of the disk manufactured by the above method to the so-called data area in a region other than the region where the ramp load is performed and where there is no regular contact with the magnetic head. And the film thickness was measured at a pitch of 0.1 mm. As a result, the transition region from 90% of the film thickness of the ramp load region, ie, 9.9 nm, to 110% of the film thickness of the data area, ie, 6.6 nm, was 2.4 mm. In addition, Raman spectroscopy was performed to examine the structure of the protective film layer of the disk manufactured by the above method. For simplicity, a disk without the protective film layer 4 and a disk without the protective film layer 5 were used. As an analyzer, an Ar laser (514.5 n) was used using a Raman spectroscopic analyzer 2010 manufactured by Lennyshaw.
m), measurement wave number 1000-1800 or 1000-1000
It was 2300 / cm.

As a result, as shown in FIG. 4, the protective film layer 4 is made of a typical DLC as described in the first embodiment.
The film was confirmed to be a film. The protective film layer 5 is formed as shown in FIG.
As shown in FIG. 7, as in the first embodiment, it was confirmed that the amorphous carbon was rich in nitrogen and also contained hydrogen.

On the other hand, the disk provided with the lubricant was mounted on a ramp load evaluation device and tested. 10 disks were rotated at 7,500 rpm. p. ramp load 500 m
When the test was carried out 00 times, the test was completed without crashing all 10 sheets, and the subsequent surface was carefully observed with a microscope and visually with oblique light, but no damage to the disk was found. As a result, in the magnetic recording medium according to the present invention, the thickness of the protective film in the region where the magnetic head performs the ramp load is one.
In the case of 1 nm, it was proved that the sliding resistance was sufficient.

Next, in a region other than the region where the ramp load is performed, a random seek of the magnetic head is performed at 7500 r.m. in a so-called data area (radius 21 mm to 45.5 mm) where there is no regular contact with the magnetic head. p. 0.1 g of alumina particles having an average particle diameter of 0.1 μm
Was placed on a disk and sought for 120 seconds, and then the surface was observed with a microscope and visually with oblique light. As a result, although the surface of the protective film was slightly scratched, the so-called crash that destroyed the protective film did not occur.
As a result, it has been proved that the magnetic recording medium according to the present invention can obtain a sufficient sliding reliability even though the thickness of the protective film layer in the data area is as thin as 6 nm.

As described above, the embodiments of the present invention include the following configuration examples.

In a method for manufacturing a magnetic recording medium having a magnetic film and a protective film containing carbon as a main component for protecting the magnetic film provided on a substrate, the protective film which comes into contact with the magnetic head when the magnetic head is started or stopped. Ne, A at the contact part
r, Kr, deposited by ion beam method using only the at least one hydrocarbon gas or hydrocarbon gas, of Xe, H ₂ over substantially the entire surface of the magnetic recording medium and then, Ne, A
r, Kr, a method of manufacturing a magnetic recording medium for forming a protective film by a sputtering method using at least one and N ₂ of Xe.

Further, in the method of manufacturing a magnetic recording medium provided with a magnetic film and a protective film containing carbon as a main component for protecting the magnetic film on a base, substantially the entire surface of the magnetic recording medium is covered with H ₂ , Ne, At least one of Ar, Kr and Xe and N ₂
A protective film is formed by a sputtering method, and then at least one of Ne, Ar, Kr, and Xe and a hydrocarbon gas are applied to a contact portion of the protective film that contacts the magnetic head when the magnetic head is started or stopped. Alternatively, a method for producing a magnetic recording medium in which a film is formed by an ion beam method using only a hydrocarbon gas.

Further, in a magnetic recording medium provided with a magnetic film and a protective film mainly composed of carbon for protecting the magnetic film on a substrate, the protective film which comes into contact with the magnetic head when the magnetic head is started or stopped. The contact portion of the film is composed of a diamond-like (DLC) layer mainly composed of carbon and hydrogen and an amorphous carbon layer mainly composed of carbon and nitrogen and containing hydrogen, and the portion of the protective film other than the contact portion is mainly composed of A magnetic recording medium comprising an amorphous carbon layer composed of carbon and nitrogen and containing hydrogen.

In a magnetic recording medium provided with a magnetic film and a protective film mainly composed of carbon for protecting the magnetic film on a base, the protection other than the portion that comes into contact with the magnetic head when the magnetic head is started or stopped. The thickness of the film part is 10 nm
The thickness of a portion of the protective film in a portion that contacts the magnetic head when the magnetic head is started or stopped is thicker than the portion of the protective film other than the contact portion and is 20 nm or less. The rate of change in the thickness of the protective film in the radial direction at the boundary between the protective film and the portion of the protective film other than the contact portion is greater than the rate of change in the thickness of the protective film other than the contact portion in the radial direction. A magnetic recording medium having a value of 1.0 nm / mm or more.

[0116]

According to the present invention, in a method for manufacturing a magnetic recording medium having a magnetic film and a protective film containing carbon as a main component for protecting the magnetic film on a substrate, a method for starting or stopping a magnetic head is provided. At least one of Ne, Ar, Kr, and Xe is deposited on a contact portion of the protective film in contact with the magnetic head by an ion beam method using a hydrocarbon gas or only a hydrocarbon gas. H is applied to almost the entire surface of the medium.
_2, Ne, Ar, Kr, or to form a protective film by a sputtering method using at least one and N ₂ of Xe, or substantially the entire surface H _2, Ne of the magnetic recording medium, Ar,
A protective film is formed by a sputtering method using at least one of Kr and Xe and N ₂ , and then Ne, Ar, Kr, and Kr are added to a contact portion of the protective film that contacts the magnetic head when the magnetic head is started or stopped. By forming a film by an ion beam method using at least one of Xe and a hydrocarbon gas or only a hydrocarbon gas, it is possible to obtain a method of manufacturing a magnetic recording medium which can perform high-density recording and has excellent reliability. .

Since the contact portion of the protective film that comes into contact with the magnetic head when starting or stopping the magnetic head is formed by the ion beam method, the boundary between the contact portion and the other portion has a steep curved surface. Thus, the recording area can be efficiently expanded.

Further, by combining the present magnetic recording medium and a magnetic head, it is possible to provide a large capacity and highly reliable magnetic disk drive.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a magnetic recording medium according to an embodiment of the present invention.

FIG. 2 is a schematic view of a protective film forming chamber 21.

FIG. 3 is a schematic view of a protective film forming chamber 31.

FIG. 4 is a spectrum of a result of Raman spectroscopic analysis of a protective film layer formed by an ion beam deposition method according to the embodiment of the present invention.

FIG. 5 is a spectrum of a result of Raman spectroscopic analysis of a protective film layer formed by a sputtering method according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating an overall configuration of a magnetic storage device.

FIG. 7 is a schematic perspective view of a magnetic head.

FIG. 8 is a diagram showing a cross-sectional structure of a magnetoresistive sensor.

FIG. 9 is a cross-sectional view of a sensor using a spin valve magnetic head.

FIG. 10 is a schematic diagram of a protective film forming chamber 21 for forming a film on the outer peripheral side of a magnetic recording medium.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Non-magnetic substrate 2 Cr alloy underlayer 3 Co alloy magnetic layer 4 Protective film layer 5 Protective film layer 21 Protective film forming room 22 Hot filament 23 Anode electrode 24 Hot filament 25 Evaporated particle shield 31 Protective film forming room 61 Magnetic recording medium 62 Driving unit for driving a magnetic recording medium 63 Magnetic head comprising a recording unit and a reproducing unit 64 Means for moving a magnetic head relative to the magnetic recording medium 65 Signal input means to the magnetic head and output signal reproduction Recording / reproducing signal processing means 601 Base 602 Coil 603 Upper recording magnetic pole 604 Lower recording magnetic pole and upper shield layer 605 Magnetoresistance sensor 606 Electrode pattern at both ends of magnetoresistance sensor 607 Lower shield layer 608 Gap layer 700 Aluminum oxide gap layer 701 Magnetic sensor Signal detection area 702 Layer 703 Separation layer 704 for preventing sense current shunting 704 Magnetoresistive ferromagnetic layer 705 Tapered portion 706 processed into a tapered shape 706 Permanent magnet layer 801 Ta buffer layer 802 First magnetic layer 803 Nonmagnetic intermediate layer made of copper 804 2 magnetic layer 805 antiferromagnetic alloy layer

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01F 41/14 H01F 41/14 // H01F 10/14 10/14 (72) Inventor Yoshinori Honda Kozuhara, Odawara-shi, Kanagawa Address 2880 F-term in Storage Systems Division, Hitachi, Ltd. (Reference) 4K029 AA02 BA34 BB02 BC02 BD11 CA03 CA05 EA01 5D006 AA05 AA06 DA03 EA03 FA05 5D112 AA07 AA24 BC05 FA01 FA09 5E049 AA04 AA09 AC05 BA06 DB02 GC01 GC01 GC08

Claims (5)

[Claims] 1. A method of manufacturing a magnetic recording medium comprising: a magnetic film provided on a substrate; and a protective film mainly composed of carbon for protecting the magnetic film, wherein the magnetic head contacts the magnetic head when the magnetic head is started or stopped. At least one of Ne, Ar, Kr, and Xe is formed on the contact portion of the protective film by an ion beam method using a hydrocarbon gas or only a hydrocarbon gas, and then over substantially the entire surface of the magnetic recording medium. A method for manufacturing a magnetic recording medium, comprising forming a protective film by a physical vapor deposition method or a chemical vapor deposition method. 2. A method of manufacturing a magnetic recording medium comprising a substrate and a magnetic film provided thereon and a protective film containing carbon as a main component for protecting the magnetic film, wherein a physical vapor deposition method or a chemical vapor deposition method is applied to substantially the entire surface of the magnetic recording medium. A protective film is formed by a vapor deposition method. Next, when starting or stopping the magnetic head, Ne, Ar, Kr,
A method for manufacturing a magnetic recording medium, comprising forming a film by an ion beam method using at least one of Xe and a hydrocarbon gas or only a hydrocarbon gas. 3. A magnetic recording medium having a magnetic film provided on a substrate and a protective film mainly composed of carbon for protecting the magnetic film, wherein the magnetic head contacts with the magnetic head when the magnetic head is started or stopped. The contact portion of the film is composed of a diamond-like (DLC) layer mainly composed of carbon and hydrogen, and an amorphous carbon layer mainly composed of carbon, or carbon and nitrogen, or carbon, nitrogen and hydrogen. A magnetic recording medium, wherein a portion of the protective film other than a contact portion is mainly composed of an amorphous carbon layer made of carbon, or carbon and nitrogen, or carbon, nitrogen and hydrogen. 4. A magnetic recording medium provided with a magnetic film and a protective film mainly composed of carbon for protecting the magnetic film on a substrate, wherein a portion other than a portion which is in contact with the magnetic head when the magnetic head is started or stopped. The thickness of the portion of the protective film is 10 nm or less, and the thickness of the portion of the protective film that is in contact with the magnetic head when the magnetic head is started or stopped is smaller than that of the portion of the protective film other than the contact portion. The thickness of the protective film at the boundary between the protective film at the contact portion and the protective film other than the contact portion in the radial direction of the protective film at a boundary between the protective film and the protective film other than the contact portion; The thickness of the protective film at the contact portion is A nm, and the thickness of the protective film at portions other than the contact portion is B.
When A / B> 1.15 is satisfied and the film thickness is 90% of the film thickness A, that is, the radius position of the end in the film thickness decreasing direction giving a film thickness of 0.9 A is R1 mm. Magnetic recording characterized by satisfying | R2-R1 | <5 when a radial position of an end in a film thickness increasing direction giving a film thickness corresponding to 110% of the thickness B, that is, a film thickness of 1.1B is R2 mm. Medium. 5. A magnetic recording medium according to claim 3 or 4, a driving unit for driving the magnetic recording medium, a magnetic head having a recording unit and a reproducing unit, and signal transmission / reception between the magnetic head. A magnetic storage device comprising: a recording / reproducing signal processing unit to be performed; and a magnetoresistive head as a reproducing unit of the magnetic head.