JP2001006145A - Magnetic recording medium and manufacture of the same and magnetic storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic recording medium for ensuring high sliding resistance reliability in a hard sliding resistance test while maintaining low noise characteristics significant at the time of realizing high recording density. SOLUTION: First base layers 12 and 12' made of alloy using Ni as main components and simultaneously containing Cr and Zr are formed between a substrate 11 and magnetic layers, and second base layers 13 and 13' made of alloy using Co as main components and simultaneously containing Cr and Zr are formed on the first base layers, and third base layers 14 and 14' are formed as films for controlling crystalline orientation on the second base layers in this order. Then, magnetic layers made of alloy using cobalt as main components and protecting layers using carbon as main components are formed.

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 and a magnetic storage device capable of recording large-capacity information, and more particularly to a magnetic recording medium suitable for high-density magnetic recording and a small and large-capacity magnetic recording medium using the same. It relates to a storage device.

[0002]

2. Description of the Related Art The demand for large capacity magnetic storage devices is increasing at present. In response to this demand, in recent years, a composite head using a magnetoresistive head having high sensitivity for reproduction by separating the recording and reproduction heads has been rapidly advancing. In order to improve the sensitivity of a magnetoresistive head using the fact that the electrical resistance of the head element changes with the change in magnetic flux leakage from the medium, a magnetic layer of a type in which multiple magnetic layers are stacked via a non-magnetic layer is used. Higher sensitivity heads utilizing a very large magnetoresistance change (giant magnetoresistance effect or spin valve effect) generated in the layer are also being put to practical use. This is because the relative magnetization directions of the plurality of magnetic layers via the non-magnetic layer change due to the leakage magnetic field from the medium,
This utilizes the fact that the magnetic resistance changes.

On the other hand, factors necessary for increasing the density of the magnetic recording medium include (1) compatibility between flattening the surface due to the low flying height of the magnetic head and avoiding the head sticking phenomenon when the magnetic head is stopped, and (2) Noise reduction and (3) realization of stable magnetic characteristics with a large process margin are mentioned.

In general, in order to increase the recording density, it is necessary to reduce the distance (magnetic flying height) between the magnetic layer (recording layer) of the magnetic recording medium and the magnetic head. The head sticks to the disk by retracting the head outside the disk when the rotation of the disk is stopped in order to achieve both flattening of the surface due to the low flying height of the magnetic head and avoiding the head sticking phenomenon when the magnetic head stops. A device equipped with a mechanism for preventing the occurrence of a noise is proposed in JP-A-11-110933. This mechanism is called a load / unload mechanism, and by adopting this mechanism, it is possible to achieve both low flying height of the magnetic head and prevention of adhesion. However, when this mechanism is adopted, when the magnetic head slider is put on the magnetic disk (load) or when the magnetic head slider is separated from the magnetic disk (unload), the magnetic disk rotating at a high speed and the magnetic head slider come into contact with each other. Therefore, it is necessary to design reliability considering this.

As a technique relating to low noise, Japanese Patent Laid-Open No. 10-7
As described in Japanese Patent No. 4314, improvement can be achieved by providing a nonmagnetic alloy layer mainly composed of Co under the underlayer, and it is shown that medium noise which is a problem particularly in a magnetoresistive head can be reduced. Have been. Also, JP-A-10-143
As described in JP-A-865, this nonmagnetic alloy layer mainly containing Co contains Cr or Zr having a high tendency to oxidize, and the surface is exposed to an oxygen atmosphere to slightly oxidize the surface, thereby further reducing the medium noise. It is shown that it can be stably reduced.

Further, as described in Japanese Patent Application No. 10-128473, Co or Ni is mainly contained between the substrate and the magnetic layer,
And at least one element selected from the first group consisting of Cr, Ti, V, Mo, and Nb and at least one element selected from the second group consisting of Zr, Ta, Hf, Y, and W A first underlayer made of an alloy containing the following elements simultaneously, a second underlayer having a rough surface is formed thereon, and Ni as a main component, and Cr, Ti, V, An alloy containing at least one element selected from the first group consisting of Mo and Nb and at least one element selected from the second group consisting of Zr, Ta, Hf, Y and W at the same time By using a magnetic recording medium characterized in that a third underlayer is formed, and a fourth underlayer is further formed thereon in this order as a layer for controlling the crystal orientation, it is possible to use a severe In the sliding resistance test under the conditions, it was found that the crash hardly occurred. Here, the sliding resistance test in which dust was injected means that about 0.1 g of alumina particles having a size of about 2 microns was sprinkled on the surface of the magnetic disk in the magnetic disk device, and the seek operation of the magnetic head was repeated, thereby causing a crash. This is a test for measuring the number of seeks up to.

Further, as described in Japanese Patent Application No. 10-330544, a base film made of a non-magnetic alloy containing Cr and Ti and a Co-Cr-Pt
There has been proposed a magnetic recording medium characterized in that an intermediate layer made of a Co-Cr-Pt alloy exists between a magnetic layer made of a -Ta-based alloy.

[0008]

According to the technology described above, a Ni-20at.% Cr-10at.% Zr alloy layer is provided as a first underlayer, and a Cr-20at.% As a second underlayer is provided thereon. % Ti alloy layer, and the Cr-Ti alloy underlayer and Co-21at.% Cr-8at.% Pt-3a
Co-22at.% Cr-10at. between the magnetic layer made of t.% Ta alloy.
A magnetic disk having an intermediate layer made of a Pt alloy and a protective layer formed thereon was manufactured.
In order to achieve GB capacity, the playback output resolution is insufficient, and to solve this, the flying height of the head has been reduced,
At the same time, it became clear that improving the sliding reliability was a problem to be solved.

A first object of the present invention is to maintain high noise resistance and high output resolution, which are important for realizing a high recording density, and to provide a high sliding resistance even in the above-mentioned severe sliding resistance test. An object of the present invention is to provide a magnetic recording medium capable of ensuring dynamic reliability. A second object of the present invention is to provide a method for manufacturing such a magnetic recording medium. A third object is to provide a large-capacity magnetic storage device using the magnetic recording medium described in the first object.

[0010]

Means for Solving the Problems In order to solve the above problems, between a substrate and a magnetic layer, Ni as a main component, and Cr,
At least one element selected from the first group consisting of Ti, V, Mo, and Nb and at least one element selected from the second group consisting of Zr, Ta, Hf, Y, and W simultaneously Forming a first underlayer made of an alloy containing Co as a main component,
And at least one element selected from the first group consisting of Cr, Ti, V, Mo, and Nb and at least one element selected from the second group consisting of Zr, Ta, Hf, Y, and W Forming a second underlayer made of an alloy containing the following elements simultaneously, and further forming a third underlayer as a film for controlling crystal orientation,
Furthermore, it has been found that good results can be obtained by using a magnetic recording medium characterized by forming a magnetic layer mainly composed of Co and a protective layer mainly composed of C in this order.

The third underlayer is an underlayer made of a non-magnetic alloy containing Cr and Ti, and the third underlayer is
It is preferable to use a magnetic recording medium in which an intermediate layer made of a Co-Cr-Pt alloy exists between a magnetic layer made of a -Cr-Pt-Ta alloy and low noise characteristics and high output resolution. Further, it is preferable that the thickness of the second underlayer is 18 nm or less, because the output resolution does not decrease.
The third base layer may have a Ti addition concentration of 18 at.% To 23 a.
When the value is t.% or less, the index Siso / Nd indicating the ratio of the medium noise Nd to the isolated reproduction wave output Siso increases, which is preferable. The composition of the intermediate layer made of the Co-Cr-Pt alloy is such that when the magnetic recording medium is characterized in that the Cr concentration is 18 to 23 at.%, The Pt concentration is 8 to 13 at.%, And the balance is Co. Is preferable because low noise characteristics and high output resolution can be obtained.

Preferably, the first underlayer is substantially a Ni-Cr-Zr alloy. The first underlayer may contain an element such as Hf which is inevitably mixed when Zr is added. Further, the second underlayer is substantially made of Co-Cr-Zr.
In the case of an alloy, particularly preferable electromagnetic conversion characteristics are obtained in terms of lowering noise and increasing recording density. However, the alloy may contain a constituent element other than Zr selected from the second group.

In the method for manufacturing these magnetic recording media, a step of heating the substrate before forming the third underlayer on the substrate, and a step of heating the substrate and then forming the third underlayer in a vacuum chamber A step of sequentially forming a magnetic layer containing Co as a main component and a protective layer containing C as a main component in this order by a sputtering method, and wherein the substrate temperature at the time of forming the third underlayer and the magnetic layer is 190 ° C. or higher. By setting the substrate temperature at 260 ° C. or lower and the substrate temperature at the time of forming the protective layer at 260 ° C. or lower, a magnetic recording medium with low noise and high sliding resistance can be formed. By setting the substrate temperature at the time of forming the third underlayer and the magnetic layer to 260 ° C. or less, the substrate temperature at the time of forming the protective layer containing carbon as a main component formed thereon can also be lowered to 260 ° C. or less. A magnetic recording medium which is dense and has excellent sliding resistance can be obtained. In general, if the substrate temperature at the time of forming the magnetic film is too low, noise increases, but in the magnetic recording medium of the present invention in which the second underlayer containing Co as a main component is formed, the case where the second underlayer is not formed Since a medium with low noise can be obtained at a lower substrate temperature as compared with, it is possible to achieve both low noise and sliding reliability at a high level. This is considered to be because the crystal grains of the Cr-Ti underlayer and the magnetic layer can be refined by forming the second underlayer containing Co as a main component.

A magnetic recording medium formed by the above manufacturing method;
A driving unit for driving the magnetic recording medium, a magnetic head including a recording unit and a reproducing unit, means for moving the magnetic head relative to the magnetic recording medium, a mechanism for ramping the head, and the magnetic head In constructing a magnetic storage device having a signal input unit for inputting a signal to a magnetic head and a recording / reproducing signal processing unit for reproducing an output signal from the magnetic head, the reproducing units of the magnetic head are configured such that the magnetization directions of the magnetic heads are relatively changed by an external magnetic field. And a magnetic recording medium comprising a plurality of conductive magnetic layers that cause a large resistance change by changing the magnetic resistance, and a conductive nonmagnetic layer disposed between the conductive magnetic layers. A magnetic storage device characterized by being the magnetic recording medium described in any one of Items 1 to 7, provides high reliability by adopting a load / unload mechanism, and is small and large. A magnetic storage device having a large capacity can be provided.

Hereinafter, each element technology will be described in detail.

As described above, an alloy containing Ni as a main component and simultaneously containing Cr and Zr is used as a material constituting the first underlayer. When the first underlayer is made of an alloy containing Ni as a main component, high adhesion strength to the substrate can be obtained.
It is desirable that the magnetization of the first underlayer be so small as to be negligible when viewed from the reproducing head. By adding Cr as an additional element, the ferromagnetic component of Ni contained in the first underlayer can be effectively reduced. Further, the addition of Cr is preferable since the corrosion resistance reliability is improved. At the same time, by adding Zr, the alloy layer can be made amorphous without deteriorating the corrosion resistance. Further, the first underlayer is preferably an alloy layer made of microcrystal or substantially amorphous. By forming the first underlayer as a layer made of microcrystal or substantially amorphous, the surface shape of the second underlayer formed thereon can be stably controlled and mass-produced. This is because the surface energy and the shape of the first underlayer serving as the underlayer of the second underlayer can be made substantially constant regardless of the substrate. Here, “microcrystal” means that the crystal grain size is 8 nm or less, and “substantially amorphous” means that a diffraction pattern is observed as a halo when a selected area diffraction image is taken with a transmission electron microscope. Is defined. The fine structure of the layers constituting such a magnetic recording medium is obtained by cutting a sample thinly cut in a direction perpendicular to the substrate surface or a sample obtained by thinning the substrate by mechanical polishing from both upper and lower directions of the sample surface by an ion thinning method. It can be evaluated by thinning the film and observing the relevant portion with a transmission electron microscope at a high magnification or by observing a diffraction pattern with a selected area diffraction image.

The second underlayer is also preferably an alloy layer made of microcrystal or substantially amorphous. By forming the second underlayer as an underlayer made of microcrystalline or substantially amorphous film, the crystal grains of the third underlayer formed thereon can be made finer, and the crystal orientation can be controlled. Becomes Thereby, the size of the crystal grains constituting the magnetic layer is controlled to a fine size suitable for reducing noise,
At the same time, the direction of the magnetic anisotropy can be controlled. As described above, the material constituting the second underlayer is preferably an alloy containing Co as a main component. Further, by adding Cr and Zr at the same time to form a material containing the same kind of element as the first underlayer, the adhesion to the surface of the first underlayer is further increased, and the CSS proof stress can be improved. Cr has the effect of effectively reducing the ferromagnetic component of Co and the effect of improving the corrosion resistance, and Zr has the effect of making the alloy film amorphous without deteriorating the corrosion resistance. As a result, the magnetization of the first underlayer can be made negligibly small as viewed from the read head.

It should be noted that even if Cr, Ti, V, Mo, and Nb are added instead of Cr added to the first and second underlayers, almost the same effect as in the case of Cr can be obtained. Also, instead of Zr added to the first underlayer and the second underlayer, Ta, Hf, Y, W
Almost the same effect as that of the case of Zr can be obtained even if Zr is added. The thickness of the first underlayer is preferably 5 nm or more and 50 nm or less. If the thickness is less than 5 nm, the film may grow in an island shape instead of a continuous thin film, making it difficult to suppress the influence of adsorbed substances on the substrate surface. If the thickness exceeds 50 nm, the efficiency of mass production decreases, which is not preferable. The thickness of the second underlayer is preferably 5 nm or more and 20 nm or less. If the thickness is less than 5 nm, it may be difficult to control the crystallinity and crystal orientation of the third underlayer and the magnetic layer formed thereon since island-like growth may occur. Exceeding the range is not preferable because the output resolution decreases.

The crystal structure of the third underlayer has a body-centered cubic structure, and is preferably a nonmagnetic metal. For example, a thin film of a nonmagnetic Cr-based alloy or the like that forms a solid solution having a (100) orientation that is expected to have good crystal matching with the magnetic layer is used.
Here, the (100) orientation means that the (100) plane of the crystal is oriented parallel to the substrate surface. As the material of the third underlayer,
Cr-Ti alloy, Cr-Ti-Mo alloy, Cr-Mo alloy or the like can be used. The thickness of the third underlayer is preferably 5 nm or more and 50 nm or less. If the thickness is less than 5 nm,
It becomes difficult to control the crystallinity and crystal orientation of the magnetic layer formed thereon, and if the thickness exceeds 50 nm, the efficiency of mass production decreases, which is not preferable. When the third underlayer is made of a Cr-Ti alloy, the Ti addition concentration is set to 18 at.
It is preferably at most 3 at.%. If the concentration of Ti added to the third Cr—Ti alloy underlayer is less than 18 at.%, The crystal matching with the magnetic layer formed thereon is deteriorated. On the other hand, if the Ti addition concentration exceeds 23 at.%, The crystal grains of the underlayer become large,
The crystal grains of the magnetic layer formed continuously on the underlayer are also large, which is not preferable because the medium noise increases.

Further, the concentration of cobalt and platinum in the constituent elements of the magnetic layer is less than 80 at.
The coercive force measured by a sample vibration magnetometer at room temperature with 0 kA / m applied is preferably 240 kA / m or more. This is due to the excellent electromagnetic conversion characteristics in the high recording density region. However, if the coercive force exceeds 320 kA / m and is too high, the overwrite characteristics are degraded. Therefore, it is preferable that the coercive force of the medium is controllable within a range in which overwriting is possible. The third
A fourth underlayer such as Cr-Mo may be further provided between the underlayer and the magnetic layer. In order to improve the sliding resistance, it is preferable to provide a protective layer containing carbon as a main component on the magnetic layer and further form a lubricating layer thereon.

A magnetic recording medium, a driving unit for driving the magnetic recording medium, a magnetic head comprising a recording unit and a reproducing unit, means for moving the magnetic head relative to the magnetic recording medium, and a ramp for the head And a recording / reproducing signal processing means for reproducing a signal output from the magnetic head. By configuring with a head, and configuring the magnetic recording medium with the magnetic recording medium of the present invention as described above,
A small-sized and large-capacity magnetic storage device having high reliability and high recording density can be realized. In particular, a higher recording density and higher reliability can be obtained by combining the load / unload mechanism suitable for low flying height and the magnetic recording medium of the present invention in which a second underlayer containing Co as a main component is formed. . That is, when a load / unload mechanism is employed, the magnetic disk rotating at a high speed and the magnetic head slider come into contact with each other at the time of loading or unloading. By using the magnetic recording medium of the present invention, it is possible to increase the reliability of such contact while maintaining low noise. This is because low noise characteristics are maintained even when the substrate temperature at the time of forming the third underlayer and the magnetic layer is relatively low, so that both low noise characteristics and denseness of the protective film can be achieved.

The magneto-resistance effect type magnetic head includes:
It is desirable that the magnetoresistive sensor section is formed between two shield layers made of a soft magnetic material and separated from each other by a distance of 0.10 μm or more and 0.15 μm or less. The distance between the shield layers
If it exceeds 0.15 μm, sufficient reproduction output cannot be obtained in the maximum linear recording density region exceeding 500 kFCI. Also,
When the distance between the shield layers is smaller than 0.10 μm, it is not easy to maintain the insulation between the shield layers and the magnetoresistive sensor. The product of the thickness t of the magnetic layer of the magnetic recording medium 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
It is desirable that Br × t be not less than 3.2 mA (40 gauss / micron) and not more than 6.4 mA (80 gauss / micron). Br × t is 3.2mA
If it is smaller than (40 Gauss / micron), there is a high risk of incorrect information being reproduced due to a decrease in playback output due to long-term storage after recording, and if it exceeds 6.4 mA (80 Gauss / micron) Overwriting of time becomes difficult.

In the magnetic storage device described above, a plurality of conductive magnetic layers which generate a large change in resistance when their magnetization directions are relatively changed by an external magnetic field as a reproducing portion of the magnetic head; With a magnetoresistive sensor that includes a conductive non-magnetic layer located between layers, 400k
It is preferable because a signal recorded at the highest linear recording density exceeding FCI can be reproduced stably. Further, it is desirable to form the magnetic head on a magnetic head slider having an air bearing surface rail area of 1.4 square millimeters or less and a mass of 2 mg or less. As a result, the probability of collision between the magnetic head and the above-mentioned projections can be reduced, and at the same time, the impact in the event of a collision can be reduced, and both high recording density of 11 gigabits per square inch or more and high impact reliability can be achieved.

The second object is achieved by forming a magnetic recording medium by the following manufacturing method. That is,
First, a first underlayer is formed over a substrate by a sputtering method, a second underlayer is formed over the first underlayer, and a third underlayer is formed.
Heating the substrate before forming the underlayer, and heating the substrate. Then, the third underlayer, the magnetic layer mainly containing Co, and the protective layer mainly containing C are combined in a vacuum chamber. A step of sequentially forming by a sputtering method in order, and
The substrate temperature during the formation of the underlayer and the magnetic layer is set to 190 ° C. or more and 260 ° C. or less, and the substrate temperature during the formation of the protective layer is set to 260 ° C. or less. The formation of each underlayer is preferably performed in an independent vacuum chamber in order to enhance controllability of the discharge atmosphere. By forming the first underlayer on the substrate, the influence of the adsorbate on the substrate surface, which causes the shape of the second underlayer to fluctuate, can be reduced to a negligible level. It is preferable to use a film made of metal-metal based microcrystals or substantially amorphous as the first underlayer because the adsorbate on the substrate surface can be efficiently covered with a chemically active element.

In general, when a heating step is performed in a later step, the problem of released gas is associated with the heating step.
By forming the underlayer described above, the source of the released gas is substantially confined, and the released gas is suppressed to a level having no practical problem. After the second underlayer is formed, the magnetic layer is heated again in the adjacent vacuum chamber, and then the third underlayer is formed in the adjacent vacuum chamber. Further, the medium noise can be reduced by controlling the crystal grain size. A magnetic layer is formed on the multilayer underlayer, a protective layer containing carbon as a main component is formed, and the pressure is returned to atmospheric pressure. As a method of forming the first or second underlayer made of a microcrystalline or substantially amorphous film between the substrate and the magnetic layer, a sputtering method is preferable. This is because the range of element types that can be deposited by the sputtering method is wider than that of the plating method. This makes it possible to form a thin film containing a large amount of Cr, which is difficult with the plating method. In addition, the sputtering method has a higher adhesive strength between the formed thin film and the substrate or the adjacent thin film than the vacuum evaporation method. It has the advantage of being controllable over a wide range. After the second underlayer is formed, the surface thereof is exposed to an atmosphere containing oxygen, so that the medium noise can be reduced stably. The step of exposing the surface of the second underlayer to an oxygen atmosphere can be performed immediately after forming the second underlayer or after reheating the substrate thereafter. Further, by cooling the substrate before forming the protective layer containing carbon as a main component, a protective layer having excellent sliding reliability can be formed. The substrate can be cooled by flowing an inert gas such as nitrogen into the vacuum chamber, or by installing a water-cooled chill plate.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described in detail with reference to the drawings.

Embodiment 1 FIG. 1 is a sectional structural view of an embodiment of a magnetic recording medium according to the present invention. As the substrate 11, an aluminosilicate glass substrate having a thickness of 0.635 mm and a diameter of 2.5 inches whose surface was chemically strengthened was used. After washing this substrate, a single-wafer sputtering apparatus (M
Using DP250B), the following multilayer film was formed in 9 seconds. The chamber configuration or the station configuration of this sputtering apparatus is as shown in FIG. First, the first base layer forming chambers 22 and 22 ′ have a thickness of 4
First underlayers 12 and 12 ′ made of a 0 nm Ni-20at.% Cr-10at.% Zr alloy were formed on both sides of the substrate. The second underlayers 13 and 13 'made of a Co-30at.% Cr-10at.% Zr alloy having a thickness of 10 nm were formed thereon in the second underlayer forming chamber 23. Further, after that, the temperature of the substrate is reduced to about
After heating to 230 ° C., in an oxidation chamber 25, 99% Ar-1% O 2
Pressure of 0.67Pa (5mTorr, gas flow rate 21scc using mixed gas)
m) for 3.5 seconds, and then in a third underlayer forming chamber 26, a third layer of a Cr-20at.% Ti alloy having a thickness of 27 nm is formed.
And a magnetic layer 16 and 16 'made of a Co-22at.% Cr-12at.% Pt alloy having a thickness of 10 nm in a first magnetic layer forming chamber 27. Then, magnetic layers 17 and 17 'made of a Co-21at.% Cr-12at.% Pt-3at.% Ta alloy having a thickness of 10 nm are formed thereon in a second magnetic layer forming chamber 28, and 2. In each of the protective layer forming chambers 29 and 29 ′, protective layers 18 and 18 ′ having a total thickness of 8 nm were formed with a thickness of 4 nm. Thereafter, the substrate was taken out of the sputtering apparatus, and a lubricant containing perfluoroalkylpolyether as a main component was applied on the protective layer to form lubrication layers 19 and 19 'having a thickness of 2 nm.

The first underlayers 12 and 12 ', the second underlayers 13 and 13', the third underlayers 14 and 14 ', and the magnetic layer
For the formation of 16, 16 ', 17 and 17', Ar gas was used as the discharge gas.
And the gas pressure was 0.93 Pa (7 mTorr). Further, at the time of forming the protective layers 18 and 18 ′ made of carbon, Ar containing nitrogen was used as a discharge gas to 1.33 Pa (10 mTorr).

The magnetic recording medium thus formed is cut, and the laminated thin film portion is thinned up and down from a direction perpendicular to the film surface by an ion thinning method so that the fine structure of the first and second underlayers is reduced. Observation with a transmission electron microscope at an accelerating voltage of 200 kV revealed that the crystal grain size was 8 nm or less, and when a selected area diffraction image was taken, a halo was observed, confirming that the film was substantially amorphous.

When the magnetic properties of the obtained magnetic disk medium were evaluated using a sample vibration magnetometer, the coercive force was 248 k.
A / m, the coercive force squareness ratio was 0.76, and the product Br × t of the thickness t of the magnetic layer and the residual magnetic flux density Br was 4.64 mA (58 gauss / micron).

As the substrate 10, besides chemically strengthened aluminosilicate, soda lime glass, silicon,
Use ceramics made of borosilicate glass or the like, glass-glazed ceramics, or an Al-Mg alloy substrate in which Ni-P is electrolessly plated, or a rigid substrate made of glass in which Ni-P is electrolessly plated. be able to.

The third underlayer is used as an underlayer for controlling the crystal orientation of the magnetic layer formed thereon. By forming a second underlayer under the third underlayer,
The crystallinity of the third underlayer can be improved. In addition, by forming the second underlayer as a substantially amorphous layer containing the same element as the first underlayer, the adhesion between the second underlayer and the first underlayer is increased, and high resistance to high resistance is obtained. Sliding performance is obtained. Further, since the surface of the second underlayer does not have a periodic arrangement of atoms over a long distance, the crystal grains of the third underlayer formed thereon can be refined, and the crystal orientation can be improved. Control becomes possible. Thus, the average grain size of the crystals constituting the magnetic layer is controlled to a fine size of 15 nm or less suitable for reducing noise, and at the same time, the direction of the easy axis is parallel to the film surface suitable for in-plane magnetic recording. The direction could be controlled.

The third underlayer is made of a nonmagnetic Cr-V, Cr-Mo, Cr-Si or the like which forms an irregular solid solution that can be oriented (100) with good crystal matching with the magnetic layer. A thin film of a Cr-based alloy can also be used. For the magnetic layer, not only Co-Cr-Pt alloy but also Co as the main component to improve the coercive force
Contains Cr, Ta, and Pt to further reduce media noise
A multi-element alloy system to which SiO2, aluminum oxide, Nb, or the like is added can be used. In particular, when Ta, Nb, V, and Ti are added, the melting point of the target is lowered, and the composition separation of the Cr-containing magnetic layer is facilitated, which is preferable. 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 is practical. Specifically, in addition to Co-Cr-Pt, Co-Cr-Pt-Ta, Co-Cr-Pt-SiO
2, Co-Cr-Pt-Al2O3, Co-Cr-Pt-Mn, Co-Cr-Nb-Pt, Co-Cr-
Alloys such as V-Pt, Co-Cr-Ti-Pt, Co-Cr-Nb-Ta-Pt, and Co-Pt-Ni-SiO2 can be used. Providing a protective layer containing carbon as a main component on the magnetic layer was preferable in improving the sliding resistance.

Example 2 In the second underlayer forming chamber 23, Co-30at.% Cr-10a having a thickness of 10 nm was used.
A magnetic recording medium was formed in the same manner as in Example 1, except that the thicknesses of the second underlayers 13 and 13 'made of the t.% Zr alloy were set to 0 nm, 15 nm, 18 nm and 20 nm.

The medium is supplied with a write current of 34 mA and a sense current of
Electromagnetic conversion characteristics were measured at a peripheral speed of 3.77 m / s using a head with a shield gap length of 0.15 μm and a write gap length of 0.27 μm at 6 mA. The mechanical flying height is 22 nm. Co-30a
As the thickness of the second underlayer made of the t.% Cr-10at.% Zr alloy increased, the output of the isolated reproduction wave monotonously decreased in proportion to the thickness of the second underlayer. That is, the product Br × t of the thickness t of the magnetic layer of the magnetic recording medium 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 is the second. It is considered that the thickness decreases with an increase in the thickness of the underlayer. On the other hand, the half width of the isolated reproduction wave output slightly increased from 186 nm to 189 nm as the thickness of the second underlayer increased.

The medium noise Nd obtained by integrating up to the band of 436 kFCI hardly increased at about 29 μVrms even if the thickness of the second underlayer was increased from 0 nm to about 18 nm. The thickness increased to 29.8 μVrms when the thickness of the second underlayer was increased to 20 nm. The ratio ReMF between the output EMF and the output of the isolated reproduction wave at 207.5 kFCI was largest when the thickness of the second underlayer was 10 nm. From these results, when the thickness of the second underlayer is set to 18 nm or less, the ratio of output to noise increases, and preferably, when the thickness of the second underlayer is 10 nm, ReMF increases. It became clear.

Embodiment 3 Instead of forming the third underlayers 14 and 14 ′ made of a Cr-20at.% Ti alloy having a thickness of 27 nm in the third underlayer formation chamber 26,
r-15at.% Ti alloy, Cr-18at.% Ti alloy, Cr-23at.% Ti alloy, Cr-
Example 1 except that a 25 at.% Ti alloy target was used.
A magnetic recording medium was formed in the same manner as described above. When the substrate temperature is heated to 230 ° C., the coercive force Hc measured by applying a magnetic field in the relative running direction of the magnetic head increases with an increase in the Ti addition concentration, and 240 kA when 18 at.% Or more Ti is added. / m or more coercive force was obtained. From this result, it was found that it is preferable to add 18 at.% Or more of Ti in order to obtain a high coercive force of 240 kA / m or more.

For these media, the Nd of signals written at 415 kFCI using the same head as that described in Example 2 was compared. As a result, when a magnetic recording medium was formed using a Cr-25at.% Ti alloy target, the reproduction output of the solitary wave was 1.086 mVpp and Nd = 29.47 μVrms. On the other hand, Cr
When a magnetic recording medium is formed using a -20 at.% Ti alloy target, the reproduction output of a solitary wave is 1.23 mVpp, and Nd = 29.
26 μVrms. Also, when using a Cr-23at.% Ti alloy, the reproduction output of the solitary wave is 1.16mVpp, and the Nd value is 29.3μ.
Vrms. The disk noise was almost constant regardless of the Cr-Ti concentration. On the other hand, the reproduction output of the solitary wave decreased as the concentration of added Ti increased. When the Cr-25at.% Ti alloy target is used, the reproduction output of the solitary wave decreases due to the thickness t of the magnetic layer of the magnetic recording medium and the relative running direction of the magnetic head with respect to the magnetic recording medium during recording. This is because the product Br × t with the residual magnetic flux density Br measured by applying a magnetic field to is reduced. From these results, it is preferable that the concentration of Ti added is 23 at.

Embodiment 4 FIG. 3 is a sectional structural view of a magnetic recording medium of this embodiment, and FIG. 4 shows a chamber configuration or a station configuration of a sputtering apparatus used for forming the magnetic recording medium of this embodiment.
Shown in The magnetic recording medium of the present embodiment is the same as the medium of the first embodiment shown in FIG. 1 except that the third underlayers 14 and 14 'and the first magnetic layer
It has a structure in which fourth underlayers 15 and 15 'are further provided between 16 and 16'. The second underlayers 13 and 13 ′ were formed in the second underlayer formation chamber 23 in the same manner as in Example 1. Thereafter, the temperature of the substrate is reduced by a lamp heater in the heating chamber 24.
After heating to 230 ° C., in an oxidation chamber 25, 99% Ar-1% O 2
Exposure was performed for 3.5 seconds in an atmosphere of a pressure of 5 mTorr (gas flow rate of 21 sccm) using a mixed gas.
To form 15 nm-thick third underlayers 14 and 14 'made of Cr, and a fourth underlayer-forming chamber 26' formed thereon a 15-nm-thick C
Fourth underlayers 15 and 15 ′ made of an r-20at.% Ti alloy were formed by a sputtering method. Thereafter, a magnetic layer made of a Co-22at.% Cr-12at.% Pt alloy having a thickness of 10 nm is formed in the first magnetic layer forming chamber 27.
16 and 16 'are formed thereon, and a magnetic layer 17 and 17' made of a Co-21at.% Cr-12at.% Pt-3at.% Ta alloy having a thickness of 10 nm is formed thereon in a second magnetic layer forming chamber 28. And a protective layer 18 having a total thickness of 8 nm on each of the two protective layer forming chambers 29 and 29 ′ with a thickness of 4 nm.
And 18 'were formed. Further, the lubricating layers 19 and 19 'were formed in Example 1.
It was formed in the same manner as described above. The medium thus obtained had a coercive squareness of about 0.77, which was about 0.05 higher than that of the medium having the structure of Example 1, and a relatively high output was obtained in a high recording density region. Further, by laminating the fourth underlayers 15 and 15 ′ having different lattice constants on the third underlayers 14 and 14 ′, the laminating effect of a large number of thin films can be removed in the shearing direction during CSS. The strength has increased, and the life before crashing has been extended by about 10% when CSS is repeated.

Example 5 The temperature at which the substrate was heated by the lamp heater in the heating chamber 24 was
A magnetic recording medium was formed in the same manner as in Example 1 except that the temperature was changed from 180 ° C. to 270 ° C.

For these media, the Nd of signals written at 415 kFCI using the same head as that described in Example 2 was compared. As a result, when the substrate temperature was set to 230 ° C. as shown in FIG. 5, the disk noise Nd was 31.3 μV
It was minimized at rms. Further, as shown in FIG. 6, the output of the isolated reproduction wave of the magnetic recording medium decreased almost monotonously with the increase of the substrate temperature. Furthermore, 0-p output (Sis
o) and the accumulated medium noise (N
The ratio Siso / Nd of d) was evaluated. Here, the flying height of the head is 2
Nd was 2 nm, and Nd was a value obtained by integrating noise in a band corresponding to 7 kFCI to 436 kFCI. As shown in FIG. 7, it was found that Siso / Nd had a maximum at a substrate temperature of about 215 ° C. When examining the relationship between the output half-line recording density D50 and the substrate temperature, when the substrate temperature was 190 ° C or more and 260 ° C or less,
A recording density of D50 = 185 kFCI or more was obtained.

Using the medium of this embodiment, a magnetic disk drive similar to that of Embodiment 7 was manufactured, and about 0.1 g of alumina particles having a size of about 2 μm was sprinkled on the surface of the magnetic disk.
The seek operation of the magnetic head was repeated 200 times, and the number of seeks until a crash was measured. As a result, in a magnetic storage device formed with a substrate temperature of 270 ° C., the number of seeks until a crash occurs is the least, and it is clear that the substrate temperature is preferably set to 260 ° C. or less at the maximum to ensure reliability. became.

In FIGS. 5, 6 and 7, the results of the magnetic recording medium without the second seed layer are shown by broken lines for comparison. When the second seed layer is not formed, Nd monotonously increases as the substrate temperature is lowered to 260 ° C. or lower. In addition, Siso / Nd decreases monotonously with this.
Therefore, by forming the second seed layer, the recording / reproducing characteristics at a low substrate temperature are improved, thereby making it possible to achieve both high reliability and high recording density.

Embodiment 6 The magnetic recording medium has the same configuration as that of the magnetic recording medium described in Embodiment 1 except that the thickness of the magnetic layer is different, and the thickness of the magnetic layer is 17 nm, 21 nm, and 24 nm.
Three types of magnetic recording media having nm were produced in the same manner as in Example 1. Here, the film thickness ratio between the first magnetic layer and the second magnetic layer
1: 1.

The fine structure of the first and second underlayers of the magnetic disk medium thus formed was evaluated using a transmission electron microscope in the same manner as in Example 1, and as a result, both layers were substantially Was amorphous.

As a result of performing the CSS sliding resistance test 50,000 times, it is found that the magnetic recording medium and the magnetic head are destroyed in any of the magnetic recording media having the magnetic layer thicknesses of 17 nm, 21 nm, and 24 nm. And good sliding reliability was obtained.

FIG. 8 shows the relationship between the coercive force of these magnetic recording media and the thickness of the magnetic film. FIG. 9 shows the relationship between the coercive force squareness ratio S * and the thickness of the magnetic film. Thickness t of the magnetic layer of the magnetic recording medium
Magnetic flux density measured by applying a magnetic field in the direction of travel of the magnetic head relative to the magnetic recording medium during and after recording
FIG. 10 shows the relationship between the product Br × t of Br and the thickness of the magnetic film.

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 is greatly reduced. The in-plane coercive force Hc is approximately 242 to 248 kA / m, the coercive force squareness ratio S * is about 0.7 from 0.63 to 0.72, and the squareness ratio S is 0.75 to 0.
It was almost constant at 78. These magnetic properties were measured at 25 ° C. with a sample vibration magnetometer.

The electromagnetic conversion characteristics of these magnetic recording media are the spin valve type reproducing element described in Example 9 in which the shield gap length Gs is 0.15 μm, and the electromagnetic induction type writing element having a gap length of 0.27 μm. The measurement was performed using a head. The read element has a sense current of 6 mA and a write current I
w was 34 mA. PW50 is a digital oscilloscope (Tekt
ronix TDS544A). The thinner the magnetic layer,
Further, as shown in FIG. 11, when the magnetic layer thickness was 17 nm and the flying height of the head was 22 nm, a small value of 183 nm was obtained as shown in FIG. The output at the maximum linear recording density of 415 kFCI measured by the spectrum analyzer was 2 to 5% of the output of the isolated reproduction wave at 20 kFCI measured by the digital oscilloscope. The output at the highest linear recording density of 415 kFCI measured by the spectrum analyzer was obtained by integrating the output of the odd-order waveform until the output exceeded 100 MHz. In addition, 0-p output (SLF) of isolated reproduction wave and 415k
Ratio of integrated medium noise (Nd) when recording FCI signal Sis
o / Nd was evaluated. Here, the flying height of the head is 22 nm,
Nd is a value obtained by integrating noise in a band corresponding to 7 kFCI to 436 kFCI. In each medium, high Siso / Nd of 25 dB or more was obtained at a high recording density of 415 kFCI.

When the flying height of the head was 11 nm, the PW50 was about 174 nm even when the thickness of the magnetic layer was 20 nm.

Example 7 After forming up to the magnetic layer 16 of the magnetic disk medium having the structure shown in FIG. 1 in the same manner as in Example 1, the substrate was transferred into a vacuum chamber equipped with a water-cooled chill plate, and nitrogen gas was supplied. The substrate was cooled down to a temperature of 200 ° C. After that, the magnetic layer 17
8 ′ protective layer 18 mainly composed of carbon on
And 18 ′ and lubricating layers 19 and 19 ′ containing perfluoroalkyl polyether as main components were formed in the same manner as in Example 1.

The magnetic disk medium manufactured in the present embodiment and the magnetic disk medium manufactured in the first embodiment were both heated to a temperature of 60 ° C.
After being left in an atmosphere under a high-temperature and high-humidity condition of 80% humidity for 10 hours, the error rate was evaluated using the magnetic storage device described in Example 9 and compared with the error rate before the high-temperature and high-humidity condition was left. As a result, the error rate of the medium of the first embodiment increased by about 40%, whereas the change of the error rate of the medium of the present embodiment was 10% or less. It is considered that by forming the protective layer after cooling the substrate to lower the temperature of the substrate, a dense protective layer was obtained and the corrosion resistance was improved.

Embodiment 8 In the medium of Embodiment 1, Ni-30at.% Cr-10at.% Zr and Ni-30at.% Cr-10at.% Were used as the materials of the first underlayers 12 and 12 '.
Ta, Ni-30at.% Cr-9at.% Hf, Ni-30at.% Cr-9.8at.% Zr-0.2
at.% Hf, Ni-30at.% Cr-10at.% W, Ni-20at.% Nb-10at.% Y,
Ni-20at.% Mo-10at.% Ta, in the medium of Example 1, the second
Co-30at.% Cr-10at.% T as the material of the underlayers 13 and 13 '
a 、 Co-30at.% Cr-10at.% Hf 、 Co-30at.% Cr-9.8at.% Zr-0.2
at.% Hf, Co-30at.% Cr-10at.% Y, Co-30at.% Ti-10at.% Z
r, Co-20% Ti-15at.% Zr, Co-30at.% V-9.8at.% Zr-0.2at.%
Hf, Co-20at.% Mo-9.9at.% Zr-0.1at.% Hf, Co-20at.% Nb-
9.8at.% Zr-0.2at.% Hf, Co-30at.% Cr-10at.% W, Co-30wt.
% Cr-4.5wt.% W-1wt.% C, Co-30wt.% Cr-5.5wt.% W-1.3wt.% C
Using -1.25 wt.% Fe-2wt.% Si-3wt.% Ni, a magnetic disk medium was formed in the same manner as in Example 1. The microstructure of the first underlayer of the obtained medium was evaluated in the same manner as in Example 1. As a result, it was confirmed that the first underlayer formed using any of the materials was substantially amorphous. Was done.
As a result of evaluating these medium noises in the same manner as in Example 1, in any case, the magnetic disk medium formed by directly oxidizing the surface on the first underlayer without forming the second underlayer was obtained. The result that the medium noise was small was obtained.

In this embodiment, each layer constituting the magnetic recording medium is formed by the DC magnetron sputtering method. However, instead of the DC magnetron sputtering method, an ordinary RF sputtering method or an RF magnetron sputtering method may be used. A magnetic recording medium was formed.

The magnetic layers 16, 16 ', 17 and 1 containing Cr as a component
In the case of forming 7 ', magnetic composition separation becomes easier to progress by using RF magnetron sputtering method, more preferably RF sputtering method, rather than DC magnetron sputtering method, and media noise is reduced. Preferred above. From the viewpoint of mass production in a short time, the ordinary RF sputtering method has a lower film formation speed than the magnetron sputtering method even if the plasma is focused by a focus coil or the like. In addition, the magnetic recording medium could be formed by physical vapor deposition such as ion beam sputtering. From the viewpoint of mass production at high speed in a short time, a production method by DC magnetron sputtering is most preferable. The formation of the protective layer mainly composed of carbon
It is well known that it can be formed by CVD (chemical vapor deposition) in addition to DC magnetron sputtering. Further, by forming the first underlayer by a sputtering method,
Elements such as Cr that cannot be contained in large amounts by plating can be contained at a high concentration of 20 at.%. Further, a higher adhesive strength with the substrate was obtained as compared with the vacuum evaporation method.

Embodiment 9 The magnetic recording medium 91 described in Embodiments 1 to 8, a driving unit 92 for driving the magnetic recording medium, a magnetic head 93 including a recording unit and a reproducing unit, and the magnetic head A means 94 for making relative movement with respect to the recording medium, a signal input means for the magnetic head, a recording / reproducing signal processing means 95 for reproducing an output signal from the magnetic head, and a mechanism 96 for retreating during unloading. The magnetic storage device having the above configuration was configured as shown in FIG.

The reproducing section of the magnetic head is constituted by a magnetoresistive head. FIG. 13 is a schematic perspective view showing the structure of the magnetic head. This head has a base 40
1 is a composite type head having both an electromagnetic induction type head for recording and a magnetoresistive effect type head for reproduction formed thereon.
The recording head was composed of an upper recording magnetic pole 403 sandwiching a coil 402 and a lower recording magnetic pole / upper shield layer 404, and the gap length between the recording magnetic poles was 0.27 μm. Further, copper having a thickness of 3 μm was used for the coil. The reproducing head comprises a magnetoresistive sensor 405 and electrode patterns 406 at both ends thereof. The magnetoresistive sensor is sandwiched between a lower recording pole / upper shield layer 404 and a lower shield layer 407, and the distance between the two shield layers is 0.15.
μm. In this figure, the gap layer between the recording magnetic poles,
Also, a gap layer between the shield layer and the magnetoresistive sensor is omitted.

FIG. 14 shows a sectional structure of the magnetoresistive sensor.
The signal detection region 500 of the magnetic sensor includes a plurality of conductive magnetic layers that generate a large resistance change when their magnetization directions relatively change due to an external magnetic field, and a conductive layer disposed between the conductive magnetic layers. It is constituted by a magnetoresistive sensor (spin-valve type reproducing element) including a nonmagnetic layer.
This magnetic sensor has a structure in which a Ta buffer layer 502, a first magnetic layer 503, and an intermediate layer 50 made of copper are formed on a gap layer 501.
4, a second magnetic layer 505 and an antiferromagnetic layer 506 made of an Fe-50at.% Mn alloy are sequentially formed. A Ni-20at.% Fe alloy was used for the first magnetic layer, and cobalt was used for the second magnetic layer. Due to the exchange magnetic field from the antiferromagnetic layer,
The magnetization of the second magnetic layer is fixed in one direction. On the other hand, the direction of magnetization of the first magnetic layer, which is in contact with the second magnetic layer via the non-magnetic layer, changes due to the leakage magnetic field from the magnetic recording medium, so that a resistance change occurs.

At both ends of the signal detection area, there are tapered portions 507 which are formed into a tapered shape. The tapered portion includes a permanent magnet layer 508 for converting the first magnetic layer into a single magnetic domain, and a pair of electrodes 406 formed thereon for extracting a signal.
Consists of The permanent magnet layer needs to have a large coercive force and the magnetization direction does not easily change, and a Co-Cr-Pt alloy was used.

By combining the magnetic recording medium of the present invention described in Examples 1 to 8 with the above-described head shown in FIG.
The magnetic storage device shown in FIG. 12 was configured. With any of the above media, the magnetic storage device thus configured was able to achieve a recording density of 11 gigabits per square inch or more.

In this embodiment, the area of the air bearing surface rail is 1.4
A magnetic head having a magnetoresistive effect type magnetic head formed on a magnetic head slider having a square millimeter or less and a mass of 2 mg or less was used. By setting the area of the slider's air bearing surface rail to 1.4 square millimeters or less and the mass to 2 mg or less, the impact resistance can be improved. This makes it possible to achieve both high recording density and high impact resistance. At a recording density of 11 gigabits per square inch or more, the mean time between failures (MTBF) is 300,000 hours or more.
Was realized.

Comparative Example A magnetic recording medium similar to that of Example 1 except that the composition of the target for forming the first underlayer was changed, except that the thickness of the magnetic layer was 21 nm was formed. Al-30at.% Si, SiO2, B as a target for forming the first underlayer
Four types of magnetic recording media using four types of targets, 4C and Ti-20at.% Cr-10at.% Zr, were produced. The adhesion of the magnetic disk medium thus manufactured to the head slider after CSS was evaluated in the same manner as in Example 1, and the result was compared with the medium of Example 3. In the medium of Example 3, the adhesive force hardly changed from the initial value even after performing 50,000 times of CSS, whereas in the case of the medium of this example using B4C as the first underlayer. Had a crash in which the media surface and the sliding surface of the head slider were destroyed after 10,000 CSS operations. Further, Al-30at.% Si, SiO is used as the first underlayer.
2. In the case of the medium using Ti-20at.% Cr-10at.% Zr, the crash did not occur even after 50,000 times of CSS, but the adhesive strength was about 3 to 7 gf higher than the initial state. Then, scratches caused by sliding of the head slider were found on the surface of the medium. As described above, in the medium experimentally manufactured in this comparative example, the problem of sliding occurred earlier than in the medium of Example 1, and the magnetic recording medium of Example 1 was excellent in the high recording density region. It can be seen that it has excellent sliding reliability as well as recording / reproducing characteristics.

Example 10 In the medium of Example 1, the material of the first underlayer 12 was Ni-30at.% Cr-10at.% Ta, Ni-30at.% Cr-9at.% Hf,
30at.% Cr-9.8at.% Zr-0.2at.% Hf 、 Ni-30at.% Cr-10at.%
Using W, Ni-20at.% Nb-10at.% Y, Ni-20at.% Mo-10at.% Ta, a magnetic disk medium was formed in the same manner as in Example 1. Example 1 shows the microstructure of the first underlayer of the obtained medium.
As a result of the evaluation in the same manner as in the above case, it was confirmed that the first underlayer formed using any of the materials was substantially amorphous. As a result of performing a dust injection test on these media, the first underlayer was Co-30at.% Cr-10 in each case.
Compared to a magnetic disk medium having at.% Zr, the number of seeks up to the crash was more than three times, and the result was that the sliding resistance was excellent.

[0064]

The magnetic recording medium of the present invention has a contact
Variations and variations in adhesive strength at start / stop can be reduced, and sliding resistance in a dust injection test can be improved. Further, the magnetic recording medium of the present invention also has a feature that noise is low in a high recording density region, and is suitable for realizing a small-sized magnetic storage device having a large storage capacity and high reliability.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a magnetic recording medium of the present invention.

FIG. 2 is a schematic view illustrating a chamber configuration of a sputtering apparatus.

FIG. 3 is a schematic sectional view showing an example of the magnetic recording medium of the present invention.

FIG. 4 is a schematic view showing a chamber configuration of a sputtering apparatus.

FIG. 5 is a diagram showing the relationship between disk noise and substrate temperature of the magnetic recording medium of the present invention.

FIG. 6 is a diagram showing a relationship between an isolated reproduction wave output and a substrate temperature of the magnetic recording medium of the present invention.

FIG. 7 is a diagram showing the relationship between Siso / Nd and substrate temperature of the magnetic recording medium of the present invention.

FIG. 8 is a diagram showing the relationship between the coercive force of the magnetic recording medium of the present invention and the thickness of the magnetic layer.

FIG. 9 is a diagram showing the relationship between the coercive force squareness ratio of the magnetic recording medium of the present invention and the thickness of the magnetic layer.

FIG. 10 is a diagram showing the relationship between Brt and the thickness of a magnetic layer of the magnetic recording medium of the present invention.

FIG. 11 is a view showing the relationship between PW50 and the thickness of a magnetic layer of the magnetic recording medium of the present invention.

FIG. 12 is a schematic view of a magnetic storage device according to the present invention.

FIG. 13 is a schematic diagram showing an example of a sectional structure of a magnetoresistive sensor of a magnetic head in the magnetic storage device of the present invention.

FIG. 14 is a schematic sectional view showing an example of a sectional structure of a magnetoresistive sensor of a magnetic head in the magnetic storage device of the present invention.

[Explanation of symbols]

11 ... substrate, 12, 12 '... first underlayer, 13,
13 ': second underlayer, 14, 14': third underlayer, 15, 15 '
.., A fourth underlayer, 16, 16 ′, a first magnetic layer, 17, 17 ′, a second magnetic layer, 18, 18 ′, a protective layer, 19, 19 ′, a lubricating layer,
... substrate, 21 ... preparation chamber, 22, 22 '... first underlayer formation chamber, 23 ... second underlayer formation chamber, 24 ... heating chamber,
25 oxidation chamber, 26 third underlayer formation chamber, 26 'fourth
, A first magnetic layer forming chamber, 28 a second magnetic layer forming chamber, 29 and 29 'a protective layer forming chamber, 30 a take-out chamber, 31 a main chamber, 91 magnetic recording Medium, 92 ... Drive section for driving magnetic recording medium,
93: magnetic head, 94: means for moving the magnetic head relative to the magnetic recording medium, 95: recording / reproducing signal processing means, 96: mechanism for retreating during unloading, 401: base, 402: coil, 403: upper part Recording magnetic pole, 404: Lower recording magnetic pole and upper shield layer, 405: Magnetic resistance sensor, 406: Electrode pattern, 407: Lower shield layer, 500: Signal detection area of magnetic sensor, 501: Gap layer, 502: Ta buffer layer, 503: first magnetic layer, 504
... intermediate layer, 505 ... second magnetic layer, 506 ... antiferromagnetic layer, 507
… Taper portion, 508… permanent magnet layer.

Continued on the front page (72) Inventor Koji Sakamoto 2880 Kokuzu, Odawara-shi, Kanagawa Prefecture, Hitachi, Ltd.Storage Systems Division (72) Inventor Akira Kato 2880 Kozu, Kokuzu, Odawara-shi, Kanagawa Prefecture, Hitachi, Ltd. Storage Systems Division, Hitachi, Ltd. (72) Inventor Joe Hosoe 2880 Kozu, Odawara-shi, Kanagawa Prefecture F-term in Storage Systems Division, Hitachi, Ltd. FA04 GB01

Claims (9)

[Claims] 1. A method according to claim 1, wherein at least one element containing Ni as a main component and selected from a first group consisting of Cr, Ti, V, Mo, and Nb is provided between the substrate and the magnetic layer; , Hf, Y, W, a first underlayer made of an alloy containing at least one element selected simultaneously from the second group, and Co as a main component, and Cr, Ti , V, Mo, Nb, at least one element selected from the first group, and Zr, Ta, Hf, Y, W
Forming a second underlayer made of an alloy simultaneously containing at least one element selected from the second group consisting of: a third underlayer as a layer for controlling the crystal orientation, A magnetic recording medium comprising a magnetic layer mainly composed of Co and a protective layer mainly composed of C formed in this order. 2. The method according to claim 1, wherein the third underlayer is an underlayer made of a non-magnetic alloy containing Cr and Ti, and the third underlayer is formed of Co-Cr-Pt-T
2. The magnetic recording medium according to claim 1, wherein an intermediate layer made of a Co-Cr-Pt alloy exists between the magnetic layer made of an a-based alloy. 3. The magnetic recording medium according to claim 1, wherein the thickness of the second underlayer is 18 nm or less. 4. The method according to claim 1, wherein said third underlayer has a Ti concentration of 18 at.% To 23 at.%.
The magnetic recording medium according to any one of the above items. 5. The composition of an intermediate layer comprising a Co—Cr—Pt alloy according to claim 2, wherein the composition of Cr is 18 to 23 at.%, The concentration of Pt is 8 to 13 at.%, And the balance is Co. Magnetic recording medium. 6. The magnetic recording medium according to claim 1, wherein the first underlayer is substantially made of a Ni—Cr—Zr alloy. 7. The magnetic recording medium according to claim 1, wherein the second underlayer is substantially a Co—Cr—Zr alloy. 8. A method of manufacturing a magnetic recording medium according to claim 1, wherein the step of heating the substrate before forming the third underlayer on the substrate, After that, a step of sequentially forming a third underlayer, a magnetic layer mainly containing Co, and a protective layer mainly containing C in this order in a vacuum chamber by a sputtering method, and A method for manufacturing a magnetic recording medium, wherein the substrate temperature during formation of the underlayer and the magnetic layer is 190 ° C. or higher and 260 ° C. or lower, and the substrate temperature during formation of the protective layer is 260 ° C. or lower. 9. A magnetic recording medium, a driving unit for driving the magnetic recording medium, a magnetic head comprising a recording unit and a reproducing unit, means for moving the magnetic head relative to the magnetic recording medium, and a head In a magnetic storage device having a mechanism for ramping, a signal input means for the magnetic head, and a recording / reproducing signal processing means for reproducing an output signal from the magnetic head, the reproducing section of the magnetic head has a magnetized structure. A plurality of conductive magnetic layers that cause a large resistance change by the direction being relatively changed by an external magnetic field,
A magnetic recording medium comprising a magnetoresistive sensor including a conductive nonmagnetic layer disposed between the conductive magnetic layers, and wherein the magnetic recording medium is the magnetic recording medium according to any one of claims 1 to 7. Characteristic magnetic storage device.