JP2003217114A - Magnetic recording medium, method for producing the same and magnetic storage apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium for high density recording having excellent thermal stability and a low medium noise and to provide a magnetic storage apparatus. <P>SOLUTION: The magnetic recording medium 100 comprises, on a substrate 1, a soft magnetic layer 3, a seed layer 5 and a recording layer 6 having an artificial lattice structure. The seed layer 5 is formed of e.g. Pd and Si. Accordingly, the magnetic exchange coupling force of the recording layer 6 in the in-plane direction can be weakened. Minute recording magnetic domains can be formed in the recording layer 6, and the magnetization transition area is distinct as well. Thus, medium noise is reduced. That is, reproduction can be performed with a low medium noise even when information is recorded at a high density. The recording layer 6 having the artificial lattice structure has excellent thermal stability because of its high magnetic anisotropy. The magnetic storage apparatus provided with the magnetic recording medium as described above can achieve an area recording density of 150 Gigabits/square inch. <P>COPYRIGHT: (C)2003,JPO

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, and more particularly to a magnetic recording medium for quickly and accurately recording a large amount of information and reproducing the recorded information with low noise. The present invention also relates to a manufacturing method thereof and a magnetic storage device using the magnetic recording medium.

[0002]

2. Description of the Related Art In response to the progress of the advanced information society in recent years, there is a growing need for a large capacity and high density information recording apparatus. A magnetic storage device is known as one of the information recording devices that meet such needs. Magnetic storage devices include, for example, large servers, parallel computers,
It is used as a mass storage device for personal computers, network servers, movie servers, mobile PCs and the like. The magnetic storage device includes a magnetic recording medium on which information is recorded and a magnetic head for recording and reproducing information on the magnetic recording medium. The magnetic recording medium has a ferromagnetic thin film such as a cobalt alloy formed as a recording layer on a disk-shaped substrate by a sputtering method or the like, and on the recording layer, in order to improve sliding resistance and corrosion resistance, A protective layer and a lubricating film are formed.

With the increase in capacity of magnetic storage devices, the recording density of the magnetic recording medium has been improved by recording fine recording magnetic domains in the recording layer of the magnetic recording medium. A perpendicular magnetic recording method has been attracting attention as a method for achieving this. In the perpendicular magnetic recording method, magnetic recording is performed by using a magnetic recording medium having a recording layer exhibiting perpendicular magnetization and forming magnetic domains having perpendicular magnetization in the recording layer. In such a perpendicular magnetic recording system, since fine magnetic domains can be formed in the recording layer, the recording density of the magnetic recording medium can be increased.

As a material for the recording layer of the magnetic recording medium according to the perpendicular magnetic recording system, a Co--Cr type polycrystalline film has been used conventionally. This polycrystalline film has a structure in which a Co-rich region having ferromagnetism and a non-magnetic Cr-rich region are separated from each other, and the non-magnetic region has a magnetic mutual action acting between adjacent ferromagnetic regions. The action is cut off.

In order to further improve the areal recording density of the magnetic recording medium, it is necessary to reduce the medium noise. For that purpose, it has been known that miniaturization of the magnetization reversal unit and high sensitivity of the read head are effective. Of these, it has been found that miniaturization of magnetic crystal grains is effective for miniaturization of the magnetization reversal unit. However, if the magnetic crystal grains are made too fine, the magnetization state of the magnetic crystal grains becomes thermally unstable, so-called thermal demagnetization occurs. In order to prevent this, for example, in Japanese Patent Laid-Open No. 8-30951, a soft magnetic layer, a first seed layer made of carbon, a second seed layer, and a recording film having an artificial lattice structure are sequentially laminated on a nonmagnetic substrate. A magnetic recording medium is disclosed.

[0006]

By the way, since the artificial lattice multilayer film and the ordered lattice alloy film have high magnetic anisotropy,
High resistance to thermal disturbance is expected. However, unlike the Co—Cr-based polycrystalline film, these films have strong magnetic interaction in the in-plane direction (direction parallel to the substrate surface), so that small magnetic domains can be formed. Had the drawback of being large. In the magnetic recording medium disclosed in JP-A-8-30951, Pt or P is formed on the first seed layer made of carbon and formed on the soft magnetic layer.
By providing a second seed layer made of d and forming a Co / Pt or Co / Pd artificial lattice layer on the second seed layer, the crystal orientation of the artificial lattice layer is improved, the perpendicular magnetic anisotropy is increased, and the coercive force is increased. Is improving. However, in such a magnetic recording medium, the magnetic exchange coupling force in the in-plane direction of the recording layer becomes strong, and the transition noise that appears as jitter becomes high when the linear recording density becomes high. Was difficult. In addition, the first seed layer and the second seed layer
Since the two seed layers of the seed layer are used, the write magnetic field from the magnetic head does not reach the soft magnetic layer effectively,
There is a problem that the saturated recording characteristics are inferior.

The 24th Academic Meeting of the Japan Society for Applied Magnetics (2
In 000), Omori et al, on a substrate, using the Au-SiO ₂ and PdB-O as a seed layer, a magnetic recording using the artificial lattice layer comprising a CoB-O layer and PdB-O layer as the recording layer The medium is disclosed.

[0008] In addition, AIT-MINT Worksho
p 2001, Jack H. et al. Judy et al. Disclose a magnetic recording medium using ITO (Indium-Tin-Oxide) / Pd as a seed layer and an artificial lattice layer composed of a CoB layer and a Pd layer as a recording layer.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object thereof is magnetic recording in which the magnetic exchange coupling force in the in-plane direction of the recording layer is low and the transition noise is reduced. To provide the medium.

Another object of the present invention is to provide a magnetic storage device having excellent heat-resistant disturbance characteristics and capable of reproducing the information with a high S / N even if the information is recorded with a high areal recording density.

[0011]

According to a first aspect of the present invention, there is provided a magnetic recording medium comprising a substrate; directly or indirectly formed on the substrate, and Pd, Si, B, A seed layer formed of at least one selected from the group consisting of C and Zr; P formed directly on the seed layer,
There is provided a magnetic recording medium comprising: a magnetic recording layer which is formed by alternately stacking at least one platinum group layer of t and Pd and a Co layer and which does not contain oxygen.

The magnetic recording medium of the present invention is provided with a seed layer composed of a Pd element and at least one element selected from the group consisting of Si, B, C and Zr as an underlayer of the recording layer. The seed layer is particularly preferably formed of Pd and Si or Pd and B. When the seed layer is made of Pd and Si, 50 at%
~ 90 at% Pd and 10 at% ~ 50 at% Si
It is desirable to be formed from. Moreover, when the seed layer is formed of Pd and B, 40 at% to 80 a
It is preferably formed of t% Pd and 20 at% to 60 at% B. The seed layer preferably has a microcrystalline structure or a structure in which amorphous is partially present in the microcrystalline structure.

In the present invention, the seed layer can optimally control the crystal orientation of the recording layer formed thereon. When the seed layer is made of, for example, only Pd crystals, a recording layer with unclear grain boundaries is formed on the intermediate layer, and the magnetic exchange coupling force acting between crystal grains of the recording layer is strong in the in-plane direction. Become. Therefore, the size of the recording magnetic domain formed in the recording layer becomes large, and it is not possible to form a fine recording magnetic domain. On the other hand, when the seed layer is formed of Pd and Si or Pd and B, Si or B is segregated and present in Pd. Since the recording layer formed on the seed layer grows by using Pd in the seed layer as a nucleus, clear crystal grain boundaries are formed in the recording layer, and the magnetic exchange coupling force in the in-plane direction acting between the crystal grains is formed. Is reduced. Further, by controlling the ratio of Pd and Si or Pd and B in the seed layer to a predetermined value, the crystal orientation of the recording layer and the exchange coupling force in the in-plane direction can be optimized.
Therefore, a fine recording magnetic domain can be reliably formed in the recording layer, and the magnetization transition region becomes clear, so that noise can be reduced. That is, the magnetic recording medium of the present invention can achieve both low noise characteristics and high resolution, which are contradictory characteristics.

The thickness of the seed layer is preferably in the range of 1 nm to 30 nm. If the thickness of the seed layer is less than 1 nm, the crystal orientation of the recording layer thereon may not be controlled. If it is thicker than 30 nm, the distance between the magnetic pole of the recording magnetic head and the soft magnetic layer increases, and the recording magnetic field from the recording magnetic head may not be sufficiently applied to the recording layer. Further, the magnetic field from the recording magnetic head may be applied to the recording layer in a spread state, resulting in a decrease in resolution or an increase in disorder in the magnetization transition region, which may cause jittery noise.

In the magnetic recording medium of the present invention, the recording layer is formed directly on the seed layer, and mainly contains the platinum group element and Co.
And a platinum group element and Co are alternately laminated with a thickness of about several atoms or about one atom. As the platinum group element, for example, at least one of Pt and Pd can be used. Since such a film can be formed at room temperature or a relatively low substrate temperature and has a large magnetic anisotropy, it is optimal as a recording layer for high density recording. In the magnetic recording medium of the present invention, the recording layer does not contain oxygen (O). Further, it is desirable that the recording layer has an artificial lattice structure and exhibits perpendicular magnetization.

As used herein, the term "artificial lattice structure"
The term “structure” refers to a structure obtained by periodically stacking a plurality of different substances with a thickness of one atom or several atoms in one direction. A film having such an artificial lattice structure is also referred to as an artificial lattice film or an alternately laminated multilayer film.

The recording layer has a thickness of 0.05 nm to 0.5 n.
a Co layer having a film thickness selected from the range of m, and 0.5
Pd having a film thickness selected from the range of nm to 2 nm
Co / Pd artificial lattice film in which layers are alternately laminated, or a Co layer having a film thickness selected from the range of 0.05 nm to 0.5 nm, and a Co layer having a film thickness selected from the range of 0.1 nm to 2 nm. C in which Pt layers having a film thickness are alternately laminated
It is preferably an o / Pt artificial lattice film. The perpendicular magnetic anisotropy is most easily developed in the artificial lattice film having such a structure.

In the magnetic recording medium of the present invention, the above-mentioned C
When the recording layer is formed by using the o / Pd artificial lattice layer or the Co / Pt artificial lattice layer, the Pd layer or the Pt layer may contain an additional element. In this way, the Pd layer or P
By including the additional element in the t-layer, compositional fluctuation occurs, and the magnetic exchange coupling force in the in-plane direction of the recording layer can be reduced. The additive element is preferably Si, Zr, C or B, and B is particularly preferable. Pd layer or Pt
When it is added to the layer, the perpendicular magnetic anisotropy is less reduced than when it is added to the Co layer.

Further, a Co / Pd artificial lattice layer or C
Co in the o / Pt artificial lattice layer is preferably discontinuously distributed in the in-plane direction. Since Co distributed discontinuously in the artificial lattice layer partially cuts the magnetic exchange coupling force, the magnetic exchange coupling force in the in-plane direction of the recording layer can be reduced.

The recording layer may be formed of, for example, an aggregate of columnar crystal particles. The diameter of the column-shaped crystal particles may be 2 nm to 15 nm, and the difference between the uppermost part of the surface of the crystal particles and the lowermost part (the height position of the boundary part of the crystal particles) may be 1 nm to 10 nm. The magnetic exchange coupling force in the in-plane direction is reduced in the recording layer having such a structure, and even if a fine recording magnetic domain is formed in the recording layer, the magnetic domain exists stably, and the linear line of the magnetization transition region is present. It is also very popular.
Therefore, noise can be further reduced during reproduction.

In the present invention, the recording layer can be formed by using an ordinary sputtering apparatus. For example, two or more targets made of different materials are arranged in parallel and each target is formed. It can also be formed by alternately moving the substrate carriers relative to each other. Alternatively, at least two types of ring targets having different diameters may be arranged on the same plane and coaxially, the substrate may be arranged so as to face the targets, and the ring targets may be alternately discharged to form a film. It is possible.

From the viewpoint of magnetic characteristics, the thickness of the recording film is
5 nm-60 nm is suitable. The recording layer is on the substrate surface
The coercive force when measured in the direction perpendicular to 1.5 [k
Oe] to 10 [kOe (kiloersted)]
And is a product of the film thickness t of the recording layer and the residual magnetization Mr.
(Mr · t) is 0.3 to 1.0 m [emu / c
m ^Two] It is desirable to be in the range. Coercive force is 1.5
If it becomes smaller than [kOe], the high recording density (600 k
Output when playing back information recorded with FCI or higher)
There is a risk that it will get worse. Also, the magnetic anisotropy energy
There is a risk that it will become smaller and will easily be thermally demagnetized. Also,
The value of Mr · t is 1.0 m [emu / cm^Two] Larger
If so, the resolution will decrease and 0.3 m [emu / cm^Two]
If the value is smaller than 100, the output will be too small.
When high recording density of gigabit / square inch or more is performed
It becomes difficult to obtain sufficient recording and reproducing characteristics.

The magnetic recording medium of the present invention may include a soft magnetic layer between the substrate and the seed layer. The soft magnetic layer is
From the viewpoint of efficiently applying a magnetic field from the magnetic head to the recording layer, a microcrystalline structure in which Fe is uniformly dispersed with a nitride or a carbide of at least one element selected from Ta, Nb, and Zr. A soft magnetic film having is preferable. In addition to such a material, for example, an amorphous alloy mainly composed of Co-Zr and containing at least one element selected from Ta, Nb, and Ti may be used. Since these soft magnetic films have a large saturation magnetic flux density of 1.5 T or more, they are suitable for high density recording. Specific materials include NiFe and CoTaZ having high magnetic permeability.
r, CoNbZr, FeTaC, etc. can be used,
The magnetic layer made of these materials can be formed with a film thickness of 1000 nm or less by a sputtering method or vapor deposition.

The magnetic recording medium of the present invention may include an oxide layer containing iron oxide between the soft magnetic layer and the seed layer. The oxide layer contains iron oxide as a main component (80 vol% or more of the whole), and the oxide layer can be formed by, for example, a reactive sputtering method of iron and oxygen or a high temperature oxidation method. it can. The thickness of the oxide layer containing iron oxide as the main component is preferably 30 nm or less in order to prevent the recording efficiency from decreasing due to magnetic spacing.

The oxide layer containing iron oxide as a main component is
The wettability is low with respect to the seed layer containing Pd and Si or Pd and B. Therefore, when the seed layer is formed on the oxide layer, first, the nuclei of the crystal grains of the seed layer are dispersed in islands in the in-plane direction and are dispersed on the oxide layer. The crystal grains of the seed layer grow using the generated nuclei as a unit. Therefore, an aggregate of finely dispersed crystal grains is formed in the seed layer. Further, the crystal grains of the seed layer function as nuclei for growing the magnetic grains of the recording layer. Therefore, when the recording layer is formed on the seed layer, the magnetic particles of the recording layer grow individually and in an isolated state with the fine crystal particles of the seed layer as a unit. Therefore, relatively fine magnetic particles can be obtained in the recording layer. As described above, by forming the seed layer containing Pd and Si or Pd and B on the oxide layer containing iron oxide and forming the recording layer on the seed layer, it is possible to make the recording layer extremely fine. An aggregate of crystal particles can be formed extremely easily. The recording layer includes
Since it is possible to form a minute recording magnetic domain and the magnetization transition region becomes extremely clear, it is considered that noise can be reduced more than in the past.

The substrate of the magnetic recording medium of the present invention is, for example,
A non-magnetic substrate such as an aluminum-magnesium alloy substrate, a glass substrate or a graphite substrate can be used. The surface of the aluminum / magnesium alloy substrate may be plated with nickel / phosphorus. The substrate surface may be flattened by pressing diamond abrasive grains or a polishing tape against the substrate surface while rotating the substrate. This allows
When the magnetic head is levitated above the magnetic recording medium, the running characteristics of the magnetic head can be improved. The centerline roughness Ra of the substrate surface is preferably such that the centerline roughness of the protective layer formed on the substrate is 1 nm or less. In the case of a glass substrate, the surface may be chemically etched with a chemical such as a strong acid to flatten it. Further, by chemically forming a protrusion having a minute height, for example, 1 nm or less, a stable low flying height can be realized when a negative pressure slider is used.

An adhesive layer such as Ti may be formed on the substrate of the magnetic recording medium before the soft magnetic layer is formed in order to improve the adhesion.

The magnetic recording medium of the present invention may have a protective layer on the recording layer. Examples of the protective layer include any one of amorphous carbon, silicon-containing amorphous carbon, nitrogen-containing amorphous carbon, boron-containing amorphous carbon, silicon oxide, zirconium oxide and cubic boron nitride. It can be preferably used. As a method for forming these amorphous carbon protective layers,
For example, a method of forming by sputtering in an inert gas targeting graphite, or in a mixed gas of an inert gas and a hydrocarbon gas such as methane,
A method of forming a hydrocarbon gas, an organic compound such as alcohol, acetone, or adamantane alone or by mixing hydrogen gas or an inert gas by plasma CVD, or by ionizing the organic compound and accelerating it by applying a voltage to the substrate. There is a method of colliding and forming. Furthermore, the protective layer may be formed by an ablation method in which high-power laser light is condensed by a lens and is irradiated on a target such as graphite.

A lubricant may be applied on the protective layer in order to improve the sliding resistance. As the lubricant, a perfluoropolyether polymer lubricant whose main chain structure is composed of three elements of carbon, fluorine and oxygen is used. Alternatively, a fluorine-substituted alkyl compound can be used as a lubricant. Other organic lubricants or inorganic lubricants may be used as long as they are materials having stable sliding and durability.

A solution coating method is generally used as a method of forming these lubricants. In addition, in order to prevent global warming or to simplify the process, optical CV that does not use solvent
The lubricating film may be formed by the D method. The photo CVD method is
It is performed by irradiating a gaseous raw material of fluorinated olefin and oxygen with ultraviolet light.

As the film thickness of the lubricant, an average value of 0.
5 nm to 3 nm is suitable. If it is thinner than 0.5 nm,
If the lubrication property deteriorates and the thickness becomes thicker than 3 nm, the meniscus force becomes large and the static friction force (stiction) between the magnetic head and the magnetic disk becomes large, which is not preferable. After forming these lubricating films, heat at about 100 ° C. may be applied for 1-2 hours in nitrogen or air. This allows
Adhesion between the lubricating film and the protective layer can be improved by removing excess solvent and low molecular weight components. In addition to such post-treatment, for example, a method of irradiating ultraviolet rays with an ultraviolet lamp for a short time after forming the lubricating film may be used, and the same effect can be obtained by such a method.

According to a second aspect of the present invention, there is provided a magnetic recording medium, a substrate; a seed layer formed directly or indirectly on the substrate and containing Pd and B; and on the seed layer. A magnetic recording layer which is formed directly on the magnetic recording layer and contains at least one of Pt and Pd and B; and the average concentration of B in the seed layer is higher than the average concentration of B in the recording layer. A B concentration B1 at a boundary surface of the recording layer on the side of the seed layer, and a B concentration B2 at an intermediate portion between the boundary surface of the recording layer on the side of the seed layer and the boundary surface of the recording layer opposite to the seed layer side. Meanwhile, a magnetic recording medium satisfying the relationship of B1> B2 is provided.

In the magnetic recording medium of the second aspect of the present invention,
The seed layer contains Pd and B, the average concentration of B in the seed layer is higher than the average concentration of B in the recording layer, and the B concentration B1 at the boundary surface of the recording layer on the seed layer side,
It is preferable that the relationship of B1> B2 is established between the B concentration B2 in the middle of the boundary surface of the recording layer on the seed layer side and the boundary surface of the recording layer on the side opposite to the seed layer side. In this case, the B concentration B1 is 17.0 to 70.0a.
t%, and the B concentration B2 is 6.0 to 17.0 at%
Is desirable. Further, it is desirable to have a B concentration gradient of 0.2 to 4.2 at% / nm in the film thickness direction in the recording layer.

According to the third aspect of the present invention, a seed layer containing Pd and at least one element selected from the group consisting of Si, B, C and Zr is directly or indirectly provided on the substrate. Forming a magnetic recording layer containing at least one platinum group layer of Pt and Pd and a Co layer alternately on the seed layer and forming an oxygen-free magnetic recording layer. A method of making a medium is provided.

The seed layer contains Pd and B, the recording layer contains B, and the content B of B in the material for forming the seed layer is between the content Br of B in the material for forming the recording layer. Moreover, it is desirable that the condition of Bs> Br is satisfied. By making the content of B in the seed layer sufficiently larger than the content of B in the recording layer during film formation, part of B in the seed layer is diffused into the recording layer, and B in the crystal grain boundary portion in the recording layer is diffused. Can be promoted, and the magnetic interaction between crystal grains in the recording layer can be further reduced.

According to a fourth aspect of the present invention, a magnetic recording medium according to the first aspect; a magnetic head for recording or reproducing information; for driving the magnetic recording medium with respect to the magnetic head. And a drive device of the above.

Since the magnetic storage device of the present invention comprises the magnetic recording medium of the first aspect of the present invention, even if information is recorded at a high areal recording density, the information can be reproduced at a high S / N and is excellent. It has excellent heat disturbance characteristics.

In the magnetic storage device of the present invention, the magnetic head comprises a recording magnetic head for recording information on the magnetic recording medium and a reproducing magnetic head for reproducing the information recorded on the magnetic recording medium. Can be configured. The gap length of the recording magnetic head is preferably 0.2 μm to 0.02 μm. 400k when the gap length exceeds 0.2μm
It becomes difficult to record at a high linear recording density of FCI or higher. Further, a recording head having a gap length smaller than 0.02 μm is difficult to manufacture, and element breakdown due to static electricity is likely to occur.

The reproducing magnetic head can be constructed by using a magnetoresistive effect element. The reproducing shield interval of the reproducing magnetic head is preferably 0.2 μm to 0.02 μm. The reproduction shield interval is directly related to the reproduction resolution, and the shorter the reproduction shield interval, the higher the resolution. It is desirable that the lower limit value of the reproducing shield interval be appropriately selected within the above range depending on the stability, reliability, electric resistance characteristics, output, etc. of the element.

In the magnetic storage device of the present invention, the drive device can be constructed by using a spindle for rotationally driving the magnetic recording medium, and the rotation speed of the spindle is 30 per minute.
00 rotation to 20000 rotation is desirable. If it is slower than 3000 rpm, the data transfer rate becomes low, which is not preferable. Further, if the rotation speed exceeds 20,000 rpm, the noise and heat generation of the spindle will increase, which is not desirable. Considering these rotation speeds, the optimum relative speed between the magnetic recording medium and the magnetic head is 2 m / sec to 30 m / sec.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a magnetic recording medium and a magnetic storage device using the same according to the present invention will be specifically described below with reference to the drawings. In the following examples, magnetic disks (hard disks) were produced as magnetic recording media. However, the present invention is applicable to flexible disks, magnetic tapes,
It can also be applied to a type of recording medium such as a magnetic card in which a magnetic head and a magnetic recording medium come into contact with each other during recording or reproduction.

[0042]

EXAMPLE 1 FIG. 1 shows a schematic sectional view of a magnetic recording medium of the present invention. The magnetic recording medium 100 includes a soft magnetic layer 3, an iron oxide layer 4, a seed layer 5, a recording layer 6, a protective layer 7, and a lubricating layer 8 on a substrate 1 having an adhesion layer 2. The magnetic recording medium 100 having such a laminated structure was manufactured by the following method.

First, a glass substrate 1 having a diameter of 65 mm was prepared, and Ti having a thickness of 5 nm was formed as an adhesion layer 2 on the glass substrate 1 by a continuous sputtering device.

Then, Fe ₇₉ Ta ₉ C ₁₂ was formed as a soft magnetic layer 3 on the adhesion layer 2 to a film thickness of 400 nm. Further, the formed Fe ₇₉ Ta ₉ C ₁₂ was heated in a vacuum at 450 ° C. for 30 seconds by a carbon heater and then gradually cooled. Thus, the soft magnetic layer 3 containing Fe fine crystals was formed.

Next, the iron oxide layer 4 was formed on the soft magnetic layer 3 by the reactive sputtering method. That is, a mixed gas of argon and oxygen (a flow rate ratio of oxygen to argon is 20
%) Was introduced and the Fe target was DC sputtered. By the reactive sputtering, the iron oxide layer 4 is formed to a thickness of 5n.
It was formed with a film thickness of m.

Next, the substrate 1 on which the iron oxide layer 4 is formed
Was transferred to a sputtering chamber using a concentric ring target, and a seed layer 5 was formed on the iron oxide layer 4. In forming the seed layer 5, DC sputtering was performed on each of the Pd target and the Si target while introducing an argon gas into the chamber. Thereby, the iron oxide layer 4
A seed layer 5 made of Pd of 74 at% and Si of 26 at% was formed thereon to a film thickness of 4 nm.

Next, the recording layer 6 having an artificial lattice structure was formed on the seed layer 5. In forming the recording layer 6, DC sputtering is performed in Ar gas while alternately opening and closing the shutters of the Co target and the Pd target, and the recording layer 6 having an artificial lattice structure in which the Co layers and the Pd layers are alternately laminated. Was formed. The Co layer has a film thickness of 0.11 nm and the Pd layer has a film thickness of 0.92 nm.
The number of laminated o layers is 26 for Pd layers and 25 for Co layers.
It was a layer.

Next, a protective layer 7 made of amorphous carbon is formed on the recording layer 6 by a plasma CVD method to a film thickness of 3
nm. After forming the protective layer 7, the substrate was taken out from the film forming apparatus. Finally, a solution of a perfluoropolyether lubricant having a thickness of 1 nm was applied on the protective layer 7 to form a lubricating layer 8.

Thus, the magnetic recording medium 100 having the laminated structure shown in FIG. 1 was produced.

Next, the manufactured magnetic recording medium 100 is
It was incorporated into a magnetic memory device 200 having a planar structure as schematically shown in FIG. The magnetic storage device 200 includes a magnetic recording medium 100, a rotary drive unit 18 for rotationally driving the magnetic recording medium 100, a magnetic head 10, and a head drive for moving the magnetic head 10 to a desired position on the magnetic recording medium. A device 11 and a recording / reproducing signal processing device 12 are provided.
The magnetic head 10 includes a single magnetic pole type write element and a GMR (Gi
ant Magneto-Resistive) reading element, which is provided at the tip of the arm of the head drive device 11. The single-pole write element of the magnetic head 10 can record information on the magnetic recording medium by applying a magnetic field according to the data to be recorded on the magnetic recording medium at the time of recording information. Magnetic head 1
The 0 GMR read element can detect the change in the leakage magnetic field from the magnetic recording medium and reproduce the information recorded in the magnetic recording medium. Recording / reproducing signal processing device 12
Can encode data to be recorded on the magnetic recording medium 100 and transmit a recording signal to the single-pole write element of the magnetic head 10. Further, the recording / reproducing signal processing device 12
Can decode the reproduction signal from the magnetic recording medium 100 detected by the GMR reading element of the magnetic head 10.

The magnetic recording device 200 is driven to maintain the magnetic spacing (distance between the main magnetic pole surface of the magnetic head 10 and the recording layer surface of the magnetic recording medium 9) at 13 nm, and the linear recording density is 1000 kBPI and the track. Density 15
Information was recorded under the condition of 0 kTPI, and the recorded information was reproduced to evaluate the recording / reproducing characteristics.
Was obtained as 24.5 dB. Furthermore, recording / reproduction was possible at an areal recording density of 150 gigabits / square inch. In the head seek test, the magnetic head was sought from the inner circumference to the outer circumference of the magnetic recording medium 100,000 times, and the bit error of the magnetic recording medium was measured after the head seek test.
The average failure interval of 300,000 hours could be achieved. The above S / N was calculated using the following formula. S / N = 20log (S0 _-p / _Nrms ) In the formula, _{S0 -p} is from zero point to peak (zero to pe).
ak) is half the reproduced signal amplitude, and N _rms is the root mean square value of the noise amplitude measured by the spectrum analyzer.

[Measurement of Electromagnetic Conversion Characteristics] Next, the electromagnetic conversion characteristics of the magnetic recording medium were measured using a recording / reproducing tester of a spin stand. As the magnetic head of the recording / reproducing tester, a composite type head of a single magnetic pole type writing element and a GMR reading element was used. The effective write track width of the main pole (main pole) of the single-pole write element is 110 n.
m and Bs were 2.1T. The effective track width of the GMR element was 97 nm and the shield interval was 45 nm. In the recording / reproducing test, the distance between the main magnetic pole surface of the single magnetic pole type write element of the magnetic head and the recording layer surface of the magnetic recording medium was set to 13 nm. The measurement results of the electromagnetic conversion characteristics are shown in FIG. In FIG. 4, S / Nd is the S / N at 500 kFCI, and Re is the output resolution divided by the solitary wave output. For comparison, FIG. 4 shows a conventional magnetic recording medium, a magnetic recording medium using a recording layer made of a Co—Cr-based polycrystalline material (Comparative Example 1), and an in-plane magnetic recording method. The measurement results of the magnetic recording medium (Comparative Example 2) are also shown. As is clear from FIG. 4, the magnetic recording medium manufactured in this example has a better S / N ratio than the conventional magnetic recording medium.
Is obtained and the resolution is as high as 18% or more. From this, it is understood that the magnetic recording medium of the present example has reduced transition noise even in a high frequency range, and has both high resolution and high S / N.

[Observation of Cross-sectional Structure of Recording Layer] Next, the cross-sectional structure of the magnetic recording medium was observed using a high resolution transmission electron microscope. FIG. 3 schematically shows an observation result of the cross-sectional structure of the recording layer 6 having the artificial lattice structure. As shown in FIG.
The recording layer 6 was composed of an aggregate of columnar crystal particles 31, and the upper surface of each crystal particle 31 was hemispherical. The diameter d of the crystal particles was about 8 nm, and the difference h between the uppermost part A and the lowermost part B of the hemisphere on the surface of the crystal particles was 2 nm. Since the recording layer 6 is composed of such cylindrical crystal grains, the magnetic coupling force in the in-plane direction is reduced,
It is considered that fine recording bits are stabilized and the linearity of the magnetization transition region is improved.

[Measurement of Thermal Demagnetization Factor] Next, the thermal demagnetization factor of the magnetic recording medium was measured. Thermal demagnetization factor is 24
The ratio of the change in the reproduced signal amplitude with respect to time when the signal recorded at the linear recording density of 100 kFCI was reproduced under the environment of ° C was defined. FIG. 5 shows the measurement result of the thermal demagnetization rate. For comparison, FIG. 5 shows the measurement results of the magnetic recording medium of Comparative Example 1 as a conventional magnetic recording medium. As shown in FIG. 5, in the conventional magnetic recording medium, the normalized output decreases with the passage of time, whereas in the magnetic recording medium of the present embodiment, the normalized output hardly decreases with time, It can be seen that there was no thermal demagnetization. This is considered to be because the magnetic transition region of the recording layer is clear and has high linearity in the magnetic recording medium of the present example. The error rate measured on-track at 1000 kBPI was 1 × 10 ⁻⁵ or less.

Next, the Si concentration in the seed layer is set to 0 at
%, 4.1 at%, 26.0 at%, 41.0 at%,
Magnetic recording media were prepared in the same manner as above except that the contents were changed to 50.6 at% and 63.2 at%, and the S / Nd and coercive force of each magnetic recording medium were measured. The measurement results are shown in the table below.

[0056]

[Table 1]

As can be seen from the table, the S / Nd is 24.0 dB or more and the coercive force is 2 in the magnetic recording media having Si concentrations of 26.0 at% and 41.0 at% in the seed layer.
It was good as 690 [Oe]. It was found that when the Si concentration in the seed layer of the magnetic recording medium is in the range of 10 at% to 50 at%, good S / Nd and coercive force can be obtained.

[0058]

Embodiment 2 FIG. 6 shows a schematic sectional view of a magnetic recording medium of the present invention. The magnetic recording medium 300 includes a soft magnetic layer 3, a seed layer 5, a recording layer 6, a protective layer 7, and a lubricating layer 8 on a substrate 1 having an adhesion layer 2. In addition, in FIG.
The layers having the same functions as the layers constituting the magnetic recording medium of Example 1 shown in FIG. In this embodiment, the seed layer 5 is made of Pd and B, and the recording layer 6 is made of Cd.
It was formed from an artificial lattice layer in which o layers and PdB layers were alternately laminated. A method of manufacturing the magnetic recording medium 300 having such a laminated structure will be described below.

First, a glass substrate 1 having a diameter of 65 mm was prepared, and Ti having a thickness of 5 nm was formed as an adhesion layer 2 on the glass substrate 1 by a continuous sputtering device.

Then, Fe ₇₉ Ta ₉ C ₁₂ was formed as a soft magnetic layer 3 on the adhesion layer 2 in a thickness of 400 nm. Further, the formed Fe ₇₉ Ta ₉ C ₁₂ was heated in a vacuum at 450 ° C. for 30 seconds by a carbon heater and then gradually cooled. Thus, the soft magnetic layer 3 containing Fe fine crystals was formed.

Next, Pd ₆₀ B ₄₀ was formed as the seed layer 5 on the soft magnetic layer 3 to have a film thickness of 5 nm. Seed layer 5
In the film formation of, the Pd target was DC sputtered and the B target was RF sputtered while introducing an argon gas into the sputtering chamber.

Next, as the recording layer 6 on the seed layer 5,
A layer made of Co and a Pd layer containing B (hereinafter referred to as PdB
To form an artificial lattice layer. In the film formation of the artificial lattice layer, after introducing the argon gas into the sputtering chamber, only the Co target was DC sputtered when the Co layer was formed. On the other hand, when forming the PdB layer, stop the DC sputtering of the Co target,
The Pd target was DC sputtered and the B target was RF sputtered. The artificial lattice layer thus formed has a Co layer thickness of 0.16 nm and a PdB layer thickness of 0.81 nm.
The number of laminated o layers is 25 for PdB layers and 2 for Co layers.
There were 5 layers.

In this embodiment, the addition amount of B in the Pd layer of the artificial lattice layer which is the recording layer 6 is 5 at%, 11 at%, 41 at%.
A plurality of magnetic recording media were produced by changing the amount to at%. Also, a magnetic recording medium was prepared in which B was not contained in the Pd layer of the artificial lattice layer.

Next, a protective layer 7 made of amorphous carbon is formed on the recording layer 6 by plasma CVD to a thickness of 3
nm. After forming the protective layer 7, the substrate was taken out from the film forming apparatus. Finally, a solution of a perfluoropolyether lubricant having a thickness of 1 nm was applied on the protective layer 7 to form a lubricating layer 8.

Thus, the magnetic recording medium 300 having the laminated structure shown in FIG. 6 was produced.

[Measurement of S / N and coercive force] Next, the S / N and coercive force of each magnetic recording medium prepared by changing the amount of B added in the Pd layer of the artificial lattice layer were measured.
The measurement results are shown in the graphs of FIGS. 7 and 8, respectively. Figure 7
As can be seen from the graph of, the addition amount of B in the Pd layer is 5a.
The magnetic recording media of t% and 11 at% have Pd of the artificial lattice layer.
The S / N ratio was increased as compared with the magnetic recording medium in which B was not added to the layer. Further, as shown in the graph of FIG. 8, the coercive force is as high as 1500 [Oe] or more in the magnetic recording medium in which the amount of B added to the Pd layer of the artificial lattice layer is 5 at% and 11 at%. 2 for 11 at% magnetic recording medium
A coercive force of 700 [Oe] or more could be obtained. On the other hand, the coercive force was as low as 200 [Oe] or less in the magnetic recording medium in which the added amount of B in the Pd layer of the artificial lattice layer was 41 at%.

Next, the addition amount of B in the seed layer is set to 1
0.8 at%, 40.7 at%, 50.9 at%, 6
A magnetic recording medium was manufactured in the same manner as described above except that the content was changed to 3.6 at%, and S was measured for each magnetic recording medium.
/ Nd and coercive force were measured. The measurement results are shown in the table below.

[0068]

[Table 2]

As can be seen from the table, the S / Nd is 24.2 dB or more and the coercive force is 2 in the magnetic recording media in which the amount of B added in the seed layer is 40.7 at% and 50.9 at%.
It was as good as 001 [Oe] or more. It was found that good S / Nd and coercive force can be obtained when the amount of B added in the seed layer of the magnetic recording medium is in the range of 20 at% to 60 at%.

[0070]

Example 3 A magnetic recording medium was produced in the same manner as in Example 2 except that the seed layer was formed using PdC and the recording layer was an artificial lattice layer in which Co layers and PdC layers were alternately laminated. . The method for forming the seed layer was the same as in Example 2 except that the C (carbon) target was used instead of the B (boron) target, and a seed layer of Pd ₆₇ C ₃₃ was formed to a film thickness of 5 nm. did. Recording layer Co / PdC
The artificial lattice layer has a Co layer thickness of 0.16n per layer.
The film thickness of each of the m and PdC (Pd ₈₈ C ₁₂ ) layers was 0.80 nm, and the number of Co layers and PdC layers stacked was 25 layers each.

The electromagnetic conversion characteristics of this magnetic recording medium were measured in the same manner as in Example 1. Measurement result, S / N
d = 24.7 dB, Re = 18.6%, S / N
Both d and Re were good.

[0072]

[Embodiment 4] In this embodiment, the thickness of the iron oxide layer is 2 nm.
And the seed layer is formed using PdZr and the recording layer is C
A magnetic recording medium was produced in the same manner as in Example 1 except that an artificial lattice layer in which the o layers and the PdZr layers were alternately laminated was used. In forming the seed layer, argon was used as a sputtering gas, and a Pd ₉₀ Zr ₁₀ target was DC-sputtered. The thickness of the seed layer was 5 nm. In forming the recording layer, argon gas was used as the sputtering gas, and DC sputtering was performed on the Co target and the Pd ₉₀ Zr ₁₀ target while alternately opening and closing the shutters. The film thickness of one Co layer of the recording layer is 0.17 n
m, and the thickness of each PdZr layer is 0.85 nm.
The number of stacked Co layers and PdZr layers was set to 25 layers.

The electromagnetic conversion characteristics of this magnetic recording medium were measured in the same manner as in Example 1. Measurement result, S / N
d = 25.7 dB, Re = 18.1%, S / N
Both d and Re were good.

[0074]

Fifth Embodiment FIG. 9 shows a schematic sectional view of a magnetic disk 400 manufactured in this example. As shown in FIG. 9, a magnetic disk 400 was produced by sequentially laminating an adhesion layer 2, a soft magnetic layer 3, a seed layer 5, a recording layer 6 and a protective layer 7 on a substrate 1.

The substrate 1 has a diameter of 2.5 inches (6.
A glass substrate (25 cm) was prepared, and a Ti film as the adhesion layer 2 was formed on the glass substrate by a DC magnetron sputtering method in an Ar gas atmosphere. The thickness of the adhesion layer 2 is 5 nm
And

Next, a CoB film was formed as a soft magnetic layer 3 on the adhesion layer 2 by a DC magnetron sputtering method using a Co ₈₅ B ₁₅ alloy target in an Ar gas atmosphere. The film thickness of the soft magnetic layer 3 was 200 nm.

Further, a PdB film was formed as the seed layer 5 on the soft magnetic layer 3. The film formation is carried out by using the simultaneous sputtering method in an Ar gas atmosphere, Pd by the DC magnetron sputtering method, B by the RF magnetron sputtering method,
The composition of the seed layer 5 was adjusted to be Pd ₆₇ B ₃₃ . The seed layer 5 had a thickness of 4 nm.

On the seed layer 5 formed as described above, a CoB / PdB alternating multilayer film showing perpendicular magnetization was formed as the recording layer 6. The method for forming the CoB / PdB alternating multilayer film is as follows.
DC magnetron sputtering is performed by alternately opening and closing a shutter for opening and closing a Co target and a Pd target in an Ar gas atmosphere, thereby alternately laminating a magnetic layer mainly containing Co and a metal layer mainly containing Pd. A film was formed. Here, 0.14 nm Co layer and 0.94
Each of the 25 nm Pd layers was laminated. B was co-sputtered by the RF magnetron sputtering method at the time of forming the alternate multilayer film to be contained in the multilayer film. At this time, the recording layer 6 of B
The content was adjusted to be 12 at%.

Finally, C is formed as the protective layer 7 on the recording layer 6.
The film was formed by the RF magnetron sputtering method in an Ar gas atmosphere. The thickness of the protective layer 7 was 3 nm.

The structure of the magnetic disk manufactured in this example is
It was analyzed with a high resolution transmission electron microscope (TEM). TEM
Although not shown in the figure, the crystal grains and crystal grain boundary portions of the recording layer were clearly observed by the plane TEM observation. From the high angle scattering dark field image (HAADF-STEM image), it can be confirmed that many light elements are present in the crystal grain boundary part of the recording layer,
It was found that B segregated at the crystal grain boundary portion of the recording layer.

Next, the distribution of B concentration in the film thickness direction contained in the magnetic disk manufactured in this example was analyzed by X-ray photoelectron spectroscopy (XPS). The results are shown in Fig. 10. The broken line in FIG. 10 is the B concentration distribution in the film thickness direction of the magnetic disk of Example 5. However, in this experiment, etching and B concentration measurement by XPS were repeated from the protective layer side to examine the distribution of B concentration in the film thickness direction. Therefore, the horizontal axis of FIG. 10 represents the etching time. As shown in FIG. 10, the etching time is 0 to about 1 min, the protective layer is about 1 to about 1 min.
About 3 min corresponds to the region of the recording layer, about 3 to about 4.25 min to the seed layer, and about 4.25 min to the soft magnetic layer region.

In the recording layer of the magnetic disk manufactured in Example 5, as shown in FIG. 10, the B concentration decreased from the boundary surface with the seed layer toward the boundary surface with the protective layer, and A B concentration gradient occurs in the film thickness direction in the layer. It is considered that this is because a part of B contained in the seed layer diffused into the recording layer when the recording layer was formed.
The B concentration was 17.0 near the boundary surface between the recording layer and the seed layer.
At%, which is closer to the seed layer than the intermediate B concentration of 12.5 at% between the boundary surface of the recording layer on the seed layer side and the boundary surface of the recording layer on the protective layer side, the diffusion amount of B increases. Although the B concentration is high, as it goes away from the seed layer toward the protective layer from the boundary surface between the recording layer and the seed layer, the diffusion amount of B is reduced and the B concentration is reduced. The B concentration in the vicinity of the boundary surface between the recording layer and the seed layer is the B concentration distribution curve at the B concentration measurement position at the seed layer side etching time of 3.2 min with respect to the boundary surface between the recording layer and the seed layer. Tangential line and recording layer side etching time 2.8m
It was determined by the point of intersection with the tangent line of the B concentration distribution curve at the in B concentration measuring position. On the other hand, the method of obtaining the B concentration in the middle between the boundary surface of the recording layer on the seed layer side and the boundary surface of the recording layer on the protective layer side is as follows.
The density is determined by the same method as the method for obtaining the B density in the vicinity of the boundary surface between the recording layer and the seed layer, and then the intermediate position in the recording layer is determined with reference to both boundary surfaces. Then, the B density at the intermediate position in the recording layer was obtained from the positions of both boundary surfaces of the recording layer and the B density and the intermediate position.

In the magnetic disk manufactured in this example, after the film formation, the average B concentration of the recording layer was 15 at%, and the average B concentration of the seed layer was 28 at%. Since a part of B in the seed layer diffuses and flows out to the recording layer, the average B concentration after the formation of the seed layer becomes smaller than the B content (33 at%) in the seed layer forming material at the time of film formation. On the other hand, in the recording layer, B
As a result of diffusion from the seed layer, the average B concentration of the recording layer after film formation was higher than the B content (12 at%) in the recording layer forming material at the time of film formation.

Next, the magnetic disk 40 manufactured in this example.
After applying a lubricant (not shown) on the protective layer 7 of No. 0, the recording / reproducing characteristics of the magnetic disk 400 were evaluated. However, a single pole head suitable for perpendicular magnetic recording was used for recording, and a spin valve type GMR magnetic head was used for reproducing. The distance between the magnetic head surface and the magnetic disk surface was kept at 10 nm.
As a result of evaluating the magnetic disk 400, Slf / Nd = 2
3.1 was obtained. Slf has a linear recording density of 20k.
It is a reproduction output when an FCI signal is recorded, Nd is a noise level when a signal having a linear recording density of 450 kFCI is recorded, and Slf / Nd is an index of the signal-to-noise ratio of the medium.

Further, the magnetic disk 40 produced in this example.
0 was incorporated into a magnetic recording device to evaluate the recording / reproducing characteristics.

The magnetic disk 400 manufactured in this example is
The reproduction test of the magnetic disk 400 was conducted by mounting the magnetic disk 400 on a magnetic recording device. Here, 60 Gb on the magnetic disk 400
The signal corresponding to its / inch ² was recorded. The distance between the magnetic head surface of the magnetic recording device and the surface of the magnetic disk 400 was kept at 10 nm. As a result of the reproduction test, a reproduction signal having a signal-to-noise ratio S / N = 30 dB was obtained, and the error rate was 1 × 10 ⁻⁵ or less when no signal processing was performed.

[0087]

Comparative Example 3 In Comparative Example 3, a comparison with Example 5 is made. In Comparative Example 3, the content of B at the time of forming the seed layer was
A magnetic disk was manufactured in the same manner as in Example 5, except that the content was adjusted to 12 at% in the material forming the seed layer, that is, Pd: B = 88: 12. The B content of this seed layer is the same as the B content at the time of forming the recording layer.

The concentration distribution of B contained in the magnetic disk manufactured in this example was analyzed by X-ray photoelectron spectroscopy (XPS) in the same manner as in Example 5. The results are shown in Fig. 10. The solid line in FIG. 10 represents the B concentration distribution in the film thickness direction of the magnetic disk of Comparative Example 3. In the magnetic disk manufactured in this example, as shown in FIG. 10, there was almost no gradient of the B concentration in the recording layer as compared with the result of Example 5 (broken line in FIG. 10). It is considered that this is because the B content at the time of film formation of the seed layer and the B content at the time of film formation had the same value, so that B did not diffuse from the seed layer to the recording layer at the time of film formation of the recording layer. Further, comparing the results of Example 5 and Comparative Example 3 regarding the B concentration in the recording layer, as shown in FIG. 10, the B concentration in the recording layer of the magnetic disk manufactured in Example 5 was
It was larger than that produced in Comparative Example 3. This concentration difference is considered to correspond to the diffusion amount of B diffused from the seed layer to the recording layer.

The Slf / Nd of the magnetic disk manufactured in this example was measured in the same manner as in Example 5. The results are shown in Table 3 together with the results of Example 5. However, Br in Table 3 is the B content when the recording layer is formed,
Bs is the B content at the time of forming the seed layer, B1 is the B concentration in the vicinity of the interface between the recording layer after the film formation and the seed layer, and B2 is the seed layer of the recording layer after the film formation. It is the B concentration at an intermediate position between the side boundary surface and the boundary surface on the protective layer side of the recording layer.

[0090]

[Table 3]

In the magnetic disk manufactured in Comparative Example 3, as shown in Table 3, Slf / Nd = 18.1 dB,
The value was lower than that of the magnetic disk of Example 5. this is,
This is because the B content in the seed layer and the B content in the recording layer are the same, so that B was hardly diffused from the seed layer into the recording layer and segregation of B in the crystal grain boundary portion in the recording layer was not promoted. Conceivable. Therefore, as in Example 5, by making the B content at the time of forming the seed layer sufficiently larger than that of the recording layer, B was diffused from the seed layer to the recording layer, and at the crystal grain boundary portion of the recording layer. It is considered that the B segregation of B is promoted and the transition noise is reduced, so that Slf / Nd is increased.

[0092]

[Sixth Embodiment] In a sixth embodiment, when a magnetic disk is formed,
Except that various magnetic disks were produced by varying the B content of the seed layer in the range of 33.0 to 100.0 at% and the B content of the recording layer in the range of 5.0 to 15.0 at%, respectively.
A magnetic disk was manufactured in the same manner as in Example 5.

Slf / Nd of the various magnetic disks manufactured in this example was measured in the same manner as in Example 5. The results are shown in Table 4. In Table 4, Br is the B content at the time of forming the recording layer, Bs is the B content at the time of forming the seed layer, and B1 is near the boundary surface between the recording layer and the seed layer after the film formation. And B2 is the B concentration at the intermediate position between the seed layer side boundary surface of the recording layer and the protective layer side boundary surface of the recording layer after film formation. In addition, Table 4 also shows the results of Example 5 and Comparative Example 3.

[0094]

[Table 4]

As shown in Table 4, the B content Bs during film formation of the seed layer is set to 33.0 to 100.0 at% and the B content Br during film formation of the recording layer is 5.0 to 15. 0.0 at% and the difference in content between Bs and Br is 18.0 to 95.0 a.
By setting t%, Slf / N of 22.0 dB or more
It was found that d was obtained. At that time, B1 in the recording layer of the magnetic disk was 18.0 to 60.0 at%,
2 was 7.0 to 17.0 at%.

Although the magnetic recording medium of the present invention has been specifically described above, the present invention is not limited to these and may include various modifications and improvements.

[0097]

According to the magnetic recording medium of the present invention, Si, Al, Zr, Ti is used as a base of a recording layer having an artificial lattice structure.
Since the seed layer composed of Pd and at least one of B and B is used, the magnetic coupling force in the in-plane direction of the recording layer can be reduced. As a result, the disturbance in the magnetization transition region of the recording layer is reduced, so that information can be reproduced with low noise even if the linear recording density is increased. Also. Since the artificial lattice film having high magnetic anisotropy is used as the recording layer, it has high thermal stability.

According to the method of manufacturing a magnetic recording medium of the present invention, by making the B content of the seed layer sufficiently larger than the B content of the recording layer during film formation, a part of B in the seed layer is It is possible to diffuse into the recording layer, promote the segregation of B in the crystal grain boundary portion in the recording layer, and further reduce the magnetic interaction between the crystal grains in the recording layer. As a result, it is possible to provide a magnetic recording medium in which medium noise is reduced and information can be reproduced with high S / N.

Since the magnetic storage device of the present invention comprises the magnetic recording medium of the present invention, even if information is recorded at a high areal recording density of 150 gigabits / square inch (about 23.25 gigabits / square centimeter), a high S / Information can be reproduced by N, and it has high heat-resistant demagnetization characteristics.

[Brief description of drawings]

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

FIG. 2 is a schematic plan view of a magnetic storage device according to the present invention.

FIG. 3 is a diagram schematically showing a cross-sectional structure of a recording layer of a magnetic recording medium.

4 is a measurement result of electromagnetic conversion characteristics of the magnetic recording medium manufactured in Example 1. FIG.

5 is a graph of reproduction signal output with respect to time of the magnetic recording medium manufactured in Example 1. FIG.

FIG. 6 is a schematic sectional view of a magnetic recording medium manufactured in Example 2.

FIG. 7 is a graph of S / N with respect to the amount of B added to the Pd layer of the recording layer of the magnetic recording medium.

FIG. 8 is a graph of coercive force with respect to the amount of B added to the Pd layer of the recording layer of the magnetic recording medium.

FIG. 9 is a schematic cross-sectional view of a magnetic disk manufactured in Example 5.

10 is a distribution diagram of B concentration in the film thickness direction of the magnetic disks manufactured in Example 5 and Comparative Example 3. FIG.

[Explanation of symbols]

1 substrate 2 Adhesion layer 3 Soft magnetic layer 5 Seed layer 6 recording layers 7 protective layer 100, 300, 400 Magnetic recording medium 200 magnetic storage device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoru Matsunuma             Hitachima, 1-88, Torora, Ibaraki City, Osaka Prefecture             Within Kucsel Co., Ltd. (72) Inventor Takanobu Takayama             Hitachima, 1-88, Torora, Ibaraki City, Osaka Prefecture             Within Kucsel Co., Ltd. F-term (reference) 5D006 BB01 BB06 BB07 BB08 BB09                       CA01 CA03 CA04 CA05 CA06                       DA08

Claims (23)

[Claims] 1. A magnetic recording medium comprising: a substrate; formed directly or indirectly on the substrate, and comprising Pd and at least one selected from the group consisting of Si, B, C and Zr. And a magnetic recording layer which is formed directly on the seed layer and is formed by alternately laminating at least one platinum group layer of Pt and Pd and a Co layer and which does not contain oxygen. Magnetic recording medium. 2. The seed layer is 50 at% to 90 at.
% Of Pd and 10 at% to 50 at% of Si are formed, The magnetic recording medium of Claim 1 characterized by the above-mentioned. 3. The seed layer is 40 at% to 80 at
% Of Pd and 20 at% to 60 at% B are formed, The magnetic recording medium of Claim 1 characterized by the above-mentioned. 4. The magnetic recording medium according to claim 1, wherein the seed layer has a microcrystal structure or a crystal structure partially containing amorphous. 5. The film thickness of the seed layer is 1 nm to 30 nm.
The magnetic recording medium according to any one of claims 1 to 4, wherein the magnetic recording medium is within the range. 6. The recording layer has an artificial lattice structure and exhibits perpendicular magnetization, and the magnetic recording medium further comprises a soft magnetic layer between the substrate and the seed layer. The magnetic recording medium according to 1. 7. The soft magnetic layer has a structure in which a nitride or a carbide of at least one element selected from the group consisting of Ta, Nb and Zr is dispersed in Fe. 6. The magnetic recording medium according to 6. 8. The soft magnetic layer is mainly formed of Co—Zr and is formed of an amorphous alloy containing at least one element selected from the group consisting of Ta, Nb and Ti. The magnetic recording medium according to claim 6, characterized in that 9. The oxide layer containing iron oxide is provided between the soft magnetic layer and the seed layer.
9. The magnetic recording medium according to any one of items 8 to 8. 10. The magnetic recording medium according to claim 9, wherein the oxide layer has a thickness of 30 nm or less. 11. The recording layer is an artificial lattice layer of a Co layer and a Pd layer, or an artificial lattice layer of a Co layer and a Pt layer, and Co is discontinuously distributed in a direction parallel to the substrate surface. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is a magnetic recording medium. 12. Si, B, C and Z in the recording layer
The magnetic recording medium according to claim 1, containing at least one element selected from the group consisting of r. 13. The recording layer is an artificial lattice layer formed by alternately stacking Pd layers and Co layers, and the artificial lattice layer contains B, and the content of B is Pd and B. The magnetic recording medium according to claim 1, wherein the total amount is 10 at% to 40 at%. 14. The recording layer is composed of an aggregate of crystal grains, each crystal grain extends in a column shape in a direction perpendicular to the surface of the substrate, and a tip thereof is raised on the surface of the recording layer, The diameter of the crystal particles is in the range of 2 nm to 15 nm, and the height of the ridges of the crystal particles is 1 nm to 10 n.
The magnetic recording medium according to any one of claims 1 to 13, wherein m is m. 15. The recording layer has a thickness of 0.05 nm to 0.5.
Co layer having a thickness in the range of 0.5 nm to 0.5 nm to 2
The magnetic recording medium according to any one of claims 11 to 14, which is a Co / Pd artificial lattice layer formed by alternately stacking Pd layers having a film thickness within a range of nm. . 16. The recording layer has a thickness of 0.05 nm to 0.5.
Co layer having a thickness in the range of 0.1 nm to 0.1 nm to 2
15. The magnetic recording medium according to claim 11, wherein the magnetic recording medium is a Co / Pt artificial lattice layer formed by alternately stacking Pt layers having a film thickness within a range of nm. . 17. A magnetic recording medium comprising: a substrate; a seed layer formed directly or indirectly on the substrate and containing Pd and B; directly formed on the seed layer and Pt and Pd. A magnetic recording layer containing at least one of B and B, wherein the average concentration of B in the seed layer is higher than the average concentration of B in the recording layer, and the boundary surface of the recording layer on the seed layer side. Between the B concentration B1 in B and the B concentration B2 in the middle of the boundary surface of the recording layer on the seed layer side and the boundary surface of the recording layer on the side opposite to the seed layer side, B1> B2
A magnetic recording medium that satisfies the relationship. 18. The B concentration B1 is 17.0 to 70.0.
%, and the B concentration B2 is 6.0 to 17.0 at
The magnetic recording medium according to claim 17, wherein the magnetic recording medium is%. 19. The recording layer of 0.2 to 0.2 in the film thickness direction.
19. The magnetic recording medium according to claim 17, which has a B concentration gradient of 4.2 at% / nm. 20. Pd directly or indirectly on the substrate
And forming a seed layer containing at least one element selected from the group consisting of Si, B, C and Zr;
A method of manufacturing a magnetic recording medium, which comprises directly laminating at least one platinum group layer of Pt and Pd and a Co layer directly on the seed layer and forming a magnetic recording layer containing no oxygen. 21. The seed layer contains Pd and B and the recording layer contains B, and a B content Bs in the seed layer forming material and a B content Br in the recording layer forming material. 21. The manufacturing method according to claim 20, wherein the condition of Bs> Br is satisfied during the period. 22. A magnetic recording medium according to claim 1, a magnetic head for recording or reproducing information, and a drive device for driving the magnetic recording medium with respect to the magnetic head. Magnetic storage device characterized by. 23. The magnetic storage device according to claim 22, wherein the magnetic head includes a magnetoresistive effect magnetic head.