JP2002260220A - Information recording medium, its manufacturing method and information recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information recording medium having high heat stability and a reduced medium noise. SOLUTION: The information recording medium 100 has a recording-assisting layer, a seeding layer, a record-holding layer and a protective layer on a substrate. The seeding layer contains an iron oxide as the main component. The record-holding layer is constituted, for example, with a multi-layer film in which Co having high magnetic anisotropy and a platinum group element are alternately laminated. The iron oxide of the seeding layer has low wettability to the platinum group element. For this reason, when the platinum group element is formed on the seeding layer with a spattering method, the platinum group element disperses in the surface. Such a platinum group element serves as a core, thereby grows the magnetic particles of the record-holding layer. By this, it is possible to make the magnetic particles fine. The medium noise is greatly reduced and a high S/N ratio can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium for recording a large amount of information quickly and accurately, a method of manufacturing the same, and an information recording apparatus. The present invention relates to an information recording medium capable of reproducing recorded information with low noise, a method for manufacturing the same, and an information recording device.

[0002]

2. Description of the Related Art In response to the recent development of a highly information-oriented society, needs for increasing the capacity and density of information recording apparatuses are increasing. A magnetic disk device is one of information recording devices that meet such needs. In the field of magnetic recording, a perpendicular magnetic recording method has attracted attention as a technique for realizing higher density. In the perpendicular magnetic recording method, magnetic recording is performed by using a magnetic disk having a recording layer exhibiting perpendicular magnetization and forming magnetic domains having perpendicular magnetization in the recording layer. Such a perpendicular magnetic recording system,
Since the demagnetizing field decreases as the magnetic domains formed in the recording layer are reduced in order to record information at a high density, this method is suitable for increasing the density and capacity of the magnetic disk.

As a material of a recording layer of a magnetic disk according to the perpendicular magnetic recording system, a Co-Cr-based polycrystalline film has been conventionally used. Such a material has a structure in which the composition is separated into a Co-rich region (ferromagnetic particles) having ferromagnetism and a non-magnetic Cr-rich region (grain boundary portion). The non-magnetic grain boundary cuts off the function to achieve excellent high-density recording characteristics and low noise characteristics.

In the perpendicular magnetic recording system, in order to efficiently apply a magnetic field from a magnetic head to a recording layer, a recording auxiliary layer made of a soft magnetic material and a hard magnetic material for recording information are used. There has been proposed a magnetic recording medium including two magnetic films in combination with a recording holding layer.

[0005]

By the way, as a recording layer of a magnetic recording medium, a study has been made on a magnetic layer having higher magnetic anisotropy than the above-mentioned Co-Cr based polycrystalline film and having excellent resistance to thermal disturbance. Has been promoted, and as such a magnetic layer,
For example, an artificial lattice multilayer film (Alternatively laminated multilayer film) in which Co and Pd or Co and Pt are alternately laminated, Fe
There is known an ordered lattice alloy film obtained by heat-treating an alloy film of Pt or Co and Pt at a high temperature. Since these artificial lattice multilayer films and ordered lattice alloy films have high magnetic anisotropy, high resistance to thermal disturbance is expected. However, these films are Co-Cr
Unlike the system polycrystalline film, there is a problem that a small magnetic domain cannot be formed due to strong magnetic interaction in a film surface direction, and a medium noise of a transitive nature is large.

An object of the present invention is to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an information recording medium capable of reproducing information at a high S / N with a low transitional medium noise and a method of manufacturing the same. It is to provide a method.

It is another object of the present invention to provide an information recording apparatus which has excellent heat-resistant disturbance characteristics and can reproduce the information with a high S / N even if the information is recorded at a high areal recording density.

[0008]

According to a first aspect of the present invention, in an information recording medium, a recording auxiliary layer formed by using a soft magnetic material; and a perpendicular magnetization formed by using a hard magnetic material. And a seed layer containing an Fe oxide, which is located between the recording auxiliary layer and the recording holding layer.

The information recording medium of the present invention is formed of a hard magnetic material exhibiting perpendicular magnetization, and has a Fe oxide layer between a recording holding layer for recording information and a recording auxiliary layer formed of a soft magnetic material. A seed layer containing an object. The seed layer is
The nuclei of the magnetic particles constituting the record holding layer can be grown on the surface at predetermined intervals. The record holding layer preferably contains a platinum group element, and in particular, is preferably an alternately laminated multilayer film in which a platinum group element and a Co element are alternately stacked. By forming a seed layer containing Fe oxide as a base of such a recording holding layer, a recording holding layer composed of an aggregate of fine magnetic particles can be formed. The reason will be described below.

The Fe oxide contained in the seed layer has low wettability with respect to the platinum group elements constituting the recording holding layer, for example, Pt and Pd. Therefore, on such a seed layer, Pt
Alternatively, when Pd is deposited by using, for example, a sputtering method,
t or Pd is finely dispersed in the in-plane direction on the seed layer due to the surface tension and is formed. As described above, Pt or Pd which is finely dispersed on the seed layer serves as a nucleus on which the magnetic particles of the recording holding layer grow, and thus Pt or Pd is deposited thereon.
By alternately depositing o and Pt or Pd,
From these nuclei, magnetic particles grow individually and in an isolated state. Since the magnetic particles thus grown have such finely dispersed nuclei as a unit, relatively fine magnetic particles can be obtained on the seed layer. Since the recording holding layer is composed of an aggregate of such minute magnetic particles, it is possible to form minute recording magnetic domains, reduce the magnetic interaction of the magnetic particles of the recording holding layer, and perform recording. Since the boundary between the magnetic domains becomes clear, noise can be reduced.

In the present invention, the seed layer preferably contains Fe present as a metal (hereinafter referred to as Fe metal) in addition to the Fe oxide. The information recording medium having such a seed layer further reduces the medium noise. Can be.
The reason will be described below.

The seed layer containing Fe metal in addition to Fe oxide is considered to be a state in which extremely small Fe metal particles are dispersed in Fe oxide. As mentioned above,
The Fe oxide has poor wettability with, for example, a platinum group element such as Pd or Pt which is an element constituting the recording holding layer. on the other hand,
Fe metal has good wettability with Pd and Pt. Therefore, Fe
When Pd or Pt is deposited on a seed layer in which metal particles are dispersed in Fe oxide, Pd or Pt becomes Fed.
Adsorbs selectively to metals. At this time, Fe in the seed layer
Since the metal is extremely small, Pd adsorbed on Fe metal
Alternatively, Pt is much finer than when it is formed on the seed layer made of Fe oxide described above. In addition, around the Fe metal, there is Fe, which has poor wettability to Pd or Pt.
Due to the presence of the oxide, Pd or Pt deposited on the seed layer is restricted from spreading two-dimensionally, that is, in an in-plane direction, and is dispersed at predetermined intervals while maintaining a small state. Conceivable. As described above, Pd or Pt dispersed extremely finely becomes a nucleus on which the magnetic particles of the recording holding layer grow, and therefore Co and Pd or Pt
Are alternately deposited, so that the magnetic particles of the recording holding layer grow from these minute nuclei. That is, Fe
When a seed layer containing an oxide and Fe metal is used as an underlayer of the recording holding layer, the Fe metal in the seed layer serves as a nucleus for growing extremely fine magnetic particles on the recording holding layer. I have. Then, since the magnetic particles grow in units of such fine nuclei, a recording holding layer formed from the fine magnetic particles is obtained. Thereby, the magnetic domains formed in the recording holding layer are also miniaturized, and the noise can be further reduced.

In the present invention, the number of Fe atoms present as a metal in the seed layer is defined as Fe _Metal ,
When the number of atoms of Fe present as an oxide is represented by Fe _Oxide , their atomic ratio (Fe _Metal / Fe
_Oxide ) is 0.02 <(Fe _Metal / Fe
_Oxide ) <0.2 is preferably satisfied. As will be described later in the examples, when the atomic ratio is larger than 0.02, information can be recorded on the recording holding layer at high density and the information can be reproduced with high S / N. it can. However, when the atomic ratio is larger than 0.2, the amount of Fe metal in the seed layer becomes too large, and the selectivity for adsorption of the platinum group element is lost, so that fine magnetic particles may not be formed on the recording holding layer. There is.

In the present invention, the seed layer containing Fe oxide preferably contains 80 vol% or more of Fe oxide as a whole, and the seed layer is formed by oxidizing the recording auxiliary layer at a high temperature as described later. In this case, impurities other than Fe oxide or Fe metal may contain about 10 at%.

In the present invention, the recording auxiliary layer made of a soft magnetic material forms a magnetic path between the recording auxiliary layer and the magnetic head during information recording, and efficiently applies a magnetic field generated from the magnetic head to the recording holding layer. It is a layer for. The soft magnetic material forming the recording auxiliary layer includes, for example, Ta, Nb, Z in Fe.
r is mainly composed of a soft magnetic material having a microcrystalline structure in which nitride or carbide of at least one element selected from the group consisting of Co and Zr is uniformly dispersed.
An amorphous alloy containing at least one element selected from b and Ti can be suitably used.

In the information recording medium of the present invention, the thickness of the seed layer is preferably 30 nm or less in order to prevent magnetic spacing from lowering the recording efficiency.

In the information recording medium of the present invention, the recording holding layer formed by using a hard magnetic material may be a perpendicular magnetization film having magnetization in a direction perpendicular to the film surface. As such a recording holding layer, various known artificial lattice multilayer films (alternately laminated multilayer films) and ordered lattice alloy films can be used. The hard magnetic material is preferably a material mainly composed of a platinum group element and Co. The platinum group element is preferably at least one of Pt and Pd, and it is preferable that the recording holding layer is formed using an alternately laminated multilayer film in which the platinum group element and Co are alternately stacked. Alternating multilayer films and superlattice alloy films can be formed at room temperature or at a relatively low substrate temperature, so they have excellent productivity, and
Since it has high magnetic anisotropy, it has excellent heat disturbance characteristics. Therefore, it is extremely optimal as a recording holding layer for high density recording.

According to a second aspect of the present invention, an information recording medium according to the first aspect of the present invention; a magnetic head for recording or reproducing information; And a driving device for driving the information recording device.

Since the information recording apparatus of the second aspect of the present invention includes the information recording medium of the first aspect, it is possible to reproduce information recorded at high density with low noise.

According to a third aspect of the present invention, in the method for manufacturing an information recording medium having a recording holding layer and a seed layer, the seed layer is reacted with a target containing Fe using a sputtering gas containing oxygen. A manufacturing method characterized in that the method includes forming by sputtering.

In the manufacturing method of the present invention, a seed layer is formed by reactively sputtering a target mainly composed of Fe using a sputtering gas containing oxygen. The seed layer formed by such a method contains Fe oxide. According to this manufacturing method, the information recording medium of the first aspect of the present invention can be manufactured.

In the manufacturing method of the present invention, by controlling the flow rate of the oxygen gas in the sputtering gas, the seed layer can contain Fe metal in addition to the Fe oxide. As described above, when the seed layer containing Fe oxide and Fe metal is used as a base of the recording holding layer, an aggregate of fine magnetic particles can be formed on the recording holding layer. As described above, when the Fe metal is formed in the seed layer by controlling the flow rate of the oxygen gas, the surface of the seed layer is sputter-etched after forming the seed layer and before forming the recording holding layer on the seed layer. It is desirable. The reason will be described below.

After the seed layer is formed by reactive sputtering using a sputtering gas containing oxygen gas, oxygen gas remains in the film forming chamber. Since a certain period of time is required to completely exhaust the oxygen gas, a thin oxide film is formed on the surface of the Fe metal in the seed layer by the oxygen gas remaining in the chamber during that time. Such an oxide film hinders the platinum group element in the record holding layer from adsorbing to Fe metal, for example, when forming a record holding layer containing a platinum group element on the seed layer. May be reduced. Therefore, as described above, after the seed layer is formed, the surface of the seed layer is sputter-etched to remove the oxide film formed on the surface of the Fe metal, thereby forming Pd, Pt, and the like constituting the recording holding layer. Since the platinum group element can be securely adsorbed on the Fe metal on the surface of the seed layer, fine magnetic particles can be formed on the recording holding layer. The gas used for sputter etching is preferably an inert gas such as Ar, Kr, or Xe, or a mixed gas of these inert gases and hydrogen gas.

According to a fourth aspect of the present invention, in a method for manufacturing an information recording medium including a recording auxiliary layer containing Fe, a seed layer, and a recording holding layer, after forming the recording auxiliary layer, A manufacturing method is provided, which comprises forming the seed layer by oxidizing the surface of the recording auxiliary layer. According to such a manufacturing method, an information recording medium including a seed layer containing Fe oxide as a main component can be manufactured, and thus the method is optimal as a method for manufacturing the information recording medium according to the first aspect of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the information recording medium according to the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0025]

FIG. 1 is a schematic sectional view of a magnetic disk according to the present invention. The magnetic disk 10 includes, on a substrate 11, a recording auxiliary layer 12 made of a soft magnetic material, a seed layer 13 made of an Fe oxide, a recording holding layer 14 made of a hard magnetic material, and a protective layer 15. The magnetic disk 100 having such a laminated structure was manufactured by the following method.

A Co / P layer in which an FeTaC film is used as a recording auxiliary layer and Co and Pd are alternately laminated as a hard magnetic recording layer.
d A multilayer film was used. This is a case where the Fe oxide layer is formed by a reactive sputtering method.

[Formation of Recording Auxiliary Layer] As a substrate 1 for a magnetic disk, a glass substrate having a diameter of 2.5 inches (about 6.25 cm) was used. On this glass substrate 1, a recording auxiliary layer 1
As No. 2, an FeTaC film was formed by a DC magnetron sputtering method. The target was an alloy of _Fe 79 _Ta 9 _{C 1 2} Composition. The film thickness was 400 nm. The film after the film formation was subjected to a lamp heating treatment in a vacuum. Heating temperature is 45
0 ° C. By this heat treatment, Fe microcrystals precipitate in the FeTaC film, and soft magnetic characteristics appear.

[Formation of Seed Layer] Next, the recording auxiliary layer 1
The seed layer 13 was formed on the substrate 2 by a reactive sputtering method. In the formation of the seed layer 13, a 5 nm-thick Fe oxide was deposited by performing DC sputtering on an Fe target while introducing a mixed gas of Ar and oxygen (flow ratio of oxygen to Ar = 20%).

[Deposition of Recording Retaining Layer] Next, a Co / Pd alternate multilayer film was formed as the recording retaining layer 14 by DC sputtering. First, Pd was deposited to a thickness of 5 nm on the seed layer, and Co and Pd were alternately deposited thereon. Co
In the formation of the / Pd alternate multilayer film, the shutters of the Pd target and the Co target are opened and closed to obtain 0.1%.
1 nm-thick Co and 0.76 nm-thick Pd were alternately laminated, and the number of layers was 26 each. Substrate heating was not performed during the formation of the Co / Pd alternate multilayer film.

[Formation of Protective Layer] Finally, a C (carbon) film having a thickness of 8 nm was formed as a protective layer 15 by RF sputtering to obtain a magnetic disk.

[0031]

Example 2 In this example, a magnetic disk was manufactured in the same manner as in Example 1 except that the seed layer was formed by a high-temperature oxidation method. Hereinafter, a method for forming the seed layer by the high-temperature oxidation method will be described. The method for forming the layers other than the seed layer is the same as that in the first embodiment, and a description thereof will not be repeated.

In the same manner as in Embodiment 1, Fe
A recording auxiliary layer made of TaC was formed and subjected to a lamp heat treatment. After the heating is completed, it is kept in vacuum for 1 minute,
Thereafter, oxygen gas was introduced at a flow rate of 200 sccm for 3 minutes. By exposing the FeTaC film to oxygen gas while the FeTaC film is still in a high temperature state due to the residual heat of the heat treatment,
An Fe oxide film, that is, a seed layer was formed on the surface of the aC film. The thickness of the seed layer was 5 nm.

A magnetic disk was manufactured by forming a recording holding layer and a protective layer on the seed layer in the same manner as in Example 1.

[0034]

Embodiment 3 In this embodiment, the recording auxiliary layer is made of CoZrT
A magnetic disk was manufactured in the same manner as in Example 1, except that the magnetic disk was formed using the film a. In forming the recording auxiliary layer, a DC magnetron sputtering method is used, and Co ₈₀ is used as a target.
An alloy having a composition of Zr ₁₂ Ta ₈ was used. 400 nm layer thickness
And The method for forming the layers other than the recording auxiliary layer is the same as in the first embodiment.

[0035]

Embodiment 4 In this embodiment, a magnetic disk was manufactured in the same manner as in Embodiment 1, except that a Co / Pt alternating multilayer film in which Co and Pt were alternately laminated was used as a recording holding layer.
Pt was first deposited to a thickness of 5 nm on the seed layer by using a DC sputtering method for forming the Co / Pt alternate multilayer film.
On top of this, 0.12 nm thick Co and 0.80 nm thick Pt
Were alternately laminated. The number of layers was 23 each. Co / P
The substrate temperature during the formation of the t-alternate multilayer film was 250 ° C. The method for forming the layers other than the record holding layer is the same as in the first embodiment.

[0036]

Embodiment 5 In this embodiment, the seed layer has a thickness of 30 n.
A magnetic disk was produced in the same manner as in Example 1 except that m was used.

[0037]

Comparative Example 1 Example 1 was repeated except that no seed layer was provided.
A magnetic disk was produced in the same manner as described above.

[0038]

Comparative Example 2 Example 3 was repeated except that no seed layer was provided.
A magnetic disk was produced in the same manner as described above.

[0039]

Comparative Example 3 Example 4 was repeated except that no seed layer was provided.
A magnetic disk was produced in the same manner as described above.

[0040]

Comparative Example 4 A magnetic disk was manufactured in the same manner as in Example 1 except that no recording auxiliary layer was provided.

[Evaluation of Medium] After a lubricant was applied on the protective layer of the magnetic disks of Examples 1 to 5 and Comparative Examples 1 to 4, the recording and reproducing characteristics of each magnetic disk were evaluated. For evaluation of recording / reproducing characteristics, a spin stand type recording / reproducing apparatus was used. A thin-film magnetic head using a soft magnetic film having a saturation magnetic flux density of 1.6 T was used for recording, and a spin-valve GMR magnetic head was used for reproduction. The gap length of the magnetic head is 0.12 μm. The distance between the head surface and the disk surface was kept at 20 nm.

The evaluation results of the magnetic disks of the example and the comparative example are shown in the table of FIG. Here, LFop / Nd is a reproduction output LFO when a signal having a linear recording density of 10 KFCI is recorded.
p and Nd which is noise when recording 400 kFCI
And it was used as an index of S / N of the medium. D5
0 is the linear recording density at which the reproduction output drops to １ ／ of LFop, and was used as an index of the recording resolution.

It can be seen that the magnetic disks of Examples 1, 3 and 4 in which the seed layer was formed with a thickness of 5 nm by reactive sputtering obtained high LFop / Nd and good D50. Also, excellent LFop / Nd and D50 were obtained in the magnetic disk of Example 2 in which the seed layer was formed by the high-temperature oxidation method. In the magnetic disk of Example 5 in which the thickness of the seed layer was 30 nm, a high LFop /
Although Nd was obtained, a decrease in D50 was observed. On the other hand, in the magnetic disks of Comparative Examples 1 to 3 in which the seed layer was not provided, D50 was slightly higher, but LFop / N
d is clearly lower. In particular, the LFop / Nd of the magnetic disk of Comparative Example 4 having no recording auxiliary layer was extremely low.

The structure and composition of the manufactured magnetic disk were analyzed by a high-resolution transmission electron microscope (TEM) and Auger electron spectroscopy (AES).
In each of the magnetic disks of Comparative Example 4 and Comparative Example 5,
It was confirmed that a layer made of Fe oxide containing Fe and oxygen as main components was formed with a thickness of about 5 nm on the recording auxiliary layer or the glass substrate. Further, it was confirmed that the layer made of Fe oxide was formed to a thickness of about 30 nm in the magnetic disk of Example 5.

Next, the magnetic disk of the example was assembled in a magnetic disk device, and the recording and reproducing characteristics were evaluated. FIG.
FIG. 1 schematically shows the configuration of a magnetic disk drive. The magnetic disk device includes a magnetic disk 21, a magnetic head 22, a magnetic disk drive 23, a magnetic head drive 24, and an electric circuit 25. As the magnetic head 22, a recording magnetic head and a reproducing magnetic head are integrated, and a thin-film magnetic head using a soft magnetic film having a high saturation magnetic flux density of 2.1T is used as the recording head. A dual spin valve type GMR magnetic head having a giant magnetoresistance effect was used. The gap length of the magnetic head 22 is 0.1
2 μm. The magnetic disk 21 is rotated by a magnetic disk drive unit 23, and the magnetic head 22 is controlled by a magnetic head drive unit 24. The distance between the bottom surface of the magnetic head 22 and the surface of the magnetic disk 21 was kept at 12 nm.

A signal (700 kFC) corresponding to an areal density of 40 Gb / inch ² was applied to the magnetic disk manufactured in Example 2.
I) was recorded and the S / N of the disc was evaluated.
A value of 4 dB was obtained. When the error rate was measured, it was 1 × 10 ⁻⁵ or less when no signal processing was performed.

[0047]

[Embodiment 6] In this embodiment, except that the seed layer was formed so as to contain Fe oxide and Fe metal.
A magnetic disk was produced in the same manner as described above. For forming the seed layer, a reactive sputtering method is used, and 6% with respect to Ar gas.
While introducing oxygen gas at a flow rate of
C was sputtered. By such sputtering, Fe oxide and F
A seed layer containing e-metal was formed to a thickness of 5 nm.

[0048]

Embodiment 7 In this embodiment, a magnetic disk is formed in the same manner as in Embodiment 6, except that the flow rate ratio of oxygen gas to Ar gas is 2.5% when the seed layer is formed by the reactive sputtering method. Was prepared.

[0049]

Example 8 A magnetic disk was manufactured in the same manner as in Example 6, except that a Co / Pt multilayer film in which Co and Pt were alternately stacked was used as a recording holding layer. For the formation of the Co / Pt alternate multilayer film, a DC sputtering method is used. First, Pt is deposited to a thickness of 5 nm on the seed layer, and 0.12 nm thick Co and 0.80 nm Pt are alternately formed thereon. Was laminated. The number of layers was 23 each. The substrate temperature at the time of forming the Co / Pt alternating multilayer film was 200 ° C.

[0050]

Embodiment 9 In this embodiment, after forming a seed layer,
A magnetic disk was manufactured in the same manner as in Example 6, except that the surface of the seed layer was sputter-etched. In the etching treatment of the seed layer surface, after a seed layer is formed in the same manner as in Example 1, a flow rate of Ar at a flow rate at which the degree of vacuum becomes 0.9 Pa is obtained.
The surface of the seed layer was subjected to RF sputter etching by introducing a gas. The sputter etching time was 30 seconds. After this sputter etching, a recording disk and a protective layer were formed in the same manner as in Example 6 to produce a magnetic disk.

[0051]

Embodiment 10 In this embodiment, a magnetic disk was produced in the same manner as in Embodiment 6, except that the flow rate ratio of oxygen gas to Ar gas was 8% when the seed layer was formed by the reactive sputtering method. did.

[0052]

Embodiment 11 In this embodiment, a magnetic disk was formed in the same manner as in Embodiment 6, except that the flow rate ratio of oxygen gas to Ar gas was 1.5% when the seed layer was formed by the reactive sputtering method. Was prepared.

[0053]

Embodiment 12 In this embodiment, the seed layer has a thickness of 30 n.
A magnetic disk was manufactured in the same manner as in Example 6, except that the magnetic disk was formed in m.

[0054]

Embodiment 13 In this embodiment, a magnetic disk was produced in the same manner as in Embodiment 8, except that the flow rate ratio of oxygen gas to Ar gas was 8% when the seed layer was formed by the reactive sputtering method. did.

[0055]

Embodiment 14 In this embodiment, a magnetic disk was formed in the same manner as in Embodiment 8, except that the flow rate ratio of oxygen gas to Ar gas was 1.5% when the seed layer was formed by the reactive sputtering method. Was prepared.

After a lubricant was applied on the protective layer of the magnetic disk manufactured as described above, the recording / reproducing characteristics of each magnetic disk were evaluated by the same method as in the above-mentioned "medium evaluation". FIG. 4 shows the recording / reproducing characteristics of the magnetic disks of Examples 6 to 14.

FIG. 4 shows an oxide in the seed layer.
Number of Fe atoms present_{Oxi de}And as metal
Number of Fe atoms present Fe_MetalRatio to the number of atoms
(Fe _Metal/ Fe_Oxide)showed that. Number of atoms
Ratio (Fe_Metal/ Fe_{Ox ide}) Is the magnet
X-ray photoelectron spectroscopy of chemical state of seed layer of gas disk
(XPS) analysis using depth analysis
Spectrum of the seed layer composed of
Two types of peaks, an oxide-derived peak and a metal-derived peak
Determined by separating into

The magnetic disks of Examples 6 to 10, 13 and 14
High LFop / N of 21.5-27.1 dB
d is obtained. In particular, the magnetic disks of Examples 6 to 10 were used.
Is good for both LFop / Nd and D50
I understand. Fe of the magnetic disks of Examples 6 to 10
_Metal/ Fe_OxideIs 0.02 <Fe
_Metal/ Fe_Oxide<0.2
Was. Example 9 in which the surface of the seed layer was sputter-etched
In the magnetic disk of No. 2, the value of LFop / Nd is 2
It was extremely high at 7.1. In addition, oxygen during seed layer deposition
Magnetic data of Examples 11 and 15 with 1.5% gas
Discs are 15.7 db and 15.7 db for LFop / Nd, respectively.
It was as low as 4.8 dB. Magnets of Examples 11 and 15
Fe in the seed layer of the gas disk_Metal/ Fe
_OxideThe values were 0.22 and 0.21, respectively.
That is, the magnetic disks of Examples 11 and 15
Fe metal in the seed layer compared to the magnetic disk of the embodiment
Many were included. From this, Fe gold in the seed layer
Record holding layer on the seed layer to contain
When formed, the platinum group element F constituting the record holding layer
e Increase in adsorption to metal, forming fine magnetic particles
It is thought that it was getting worse. Also, the seed layer thickness
In the magnetic disk of Example 13 having a thickness of 30 nm, D5
0 was as low as 144 kFCI. This is the seed
The thickness of the layer has been increased,
The gap becomes thicker, and the magnetic field from the magnetic head
It is probable that it was not applied with sufficient magnetic field strength.

Next, the magnetic disk of Example 6 was assembled in the magnetic disk device shown in FIG. 2 in the same manner as described above, and the recording and reproducing characteristics were evaluated. A signal (700 kFC) corresponding to an areal density of 40 Gb / inch ² was applied to the magnetic disk of Example 6.
When I) was recorded and the S / N of the magnetic disk was evaluated, a value of 36 dB was obtained. When the error rate was measured, it was 1 × 10 ⁻⁵ or less when no signal processing was performed.

Although the magnetic disk of the present invention has been described with reference to the embodiments, the present invention is not limited to these embodiments.

[0061]

According to the information recording medium of the present invention, a seed layer mainly composed of Fe oxide is provided between a recording auxiliary layer made of a soft magnetic material and a recording holding layer made of a hard magnetic material. Even when a Co / Pt alternately laminated multilayer film having high magnetic anisotropy is used as the recording holding layer, the magnetic particles of the recording holding layer can be miniaturized, and fine magnetic domains are formed in the recording holding layer. It is possible to form. For this reason, medium noise is reduced, and information can be reproduced with a high S / N. In addition, since the recording holding layer can be formed using a magnetic film having high magnetic anisotropy, it has high resistance to thermal disturbance and can record information at high density. The information recording apparatus of the present invention including such an information recording medium can record information with a surface recording density exceeding 40 Gb / inch ² and can reproduce the recorded information with low noise.

According to the manufacturing method of the present invention, an information recording medium having a seed layer containing Fe oxide as a main component is manufactured by reactively sputtering an Fe metal target using a sputtering gas containing oxygen gas. This is extremely suitable as a method for manufacturing the information recording medium according to the first aspect of the present invention.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a cross-sectional structure of a magnetic disk according to the present invention.

FIG. 2 is a schematic configuration diagram of a magnetic disk drive according to the present invention.

FIG. 3 is a table showing the results of recording and reproducing characteristics of the magnetic disks of Examples 1 to 5 and Comparative Examples 1 to 4.

FIG. 4 is a table showing the results of recording and reproducing characteristics of the magnetic disks of Examples 6 to 14.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Substrate 12 Recording auxiliary layer 13 Seed layer 14 Recording holding layer 15 Protective layer 21 Magnetic disk 22 Magnetic head 23 Magnetic disk drive unit 24 Magnetic head drive unit 25 Electric circuit system

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takanobu Takayama 1-1-88 Ushitora, Ibaraki-shi, Osaka Hitachi Maxell Co., Ltd. (72) Satoru Matsunuma 1-188 Ushitora, Ibaraki-shi, Osaka Hitachi Within Maxell Corporation (72) Harumi Sakamoto 1-88 Ushitora, Ibaraki City, Osaka Prefecture Inside Hitachi Maxell Co., Ltd. (72) Koichiro Wakabayashi 1-188 Ushitora Ibaraki City, Osaka Prefecture Hitachi Maxell F term in reference (reference) 5D006 BB01 BB08 CA03 CA04 CA05 CA06 DA08 EA03 5D112 AA04 AA05 AA06 BB05 BD03 FA04 FB08 GA05 GA20 GB01

Claims (14)

[Claims] 1. An information recording medium, comprising: a recording auxiliary layer formed by using a soft magnetic material; a recording holding layer formed by using a hard magnetic material and exhibiting perpendicular magnetization; And a seed layer containing an Fe oxide. 2. The information recording medium according to claim 1, wherein the recording holding layer is an alternately laminated multilayer film in which a platinum group element and Co are alternately laminated. 3. The information recording medium according to claim 2, wherein the platinum group element is at least one of Pt and Pd. 4. The method according to claim 1, wherein the seed layer is formed of F present as a metal.
The information recording medium according to any one of claims 1 to 3, wherein the information recording medium comprises e. 5. The method according to claim 1, wherein F is present as a metal in the seed layer.
The atomic number of e and _{Fe M etal,} when the number of atoms of Fe present as oxides and _{Fe Oxide,} number their atomic ratio _Fe Metal _{/ Fe Oxide} is, 0.02
_{<(Fe Me tal / Fe Oxide} ) < information recording medium according to claim 4, characterized in that satisfy 0.2 relationships. 6. The information recording medium according to claim 1, wherein the thickness of the seed layer is 30 nm or less. 7. The recording auxiliary layer according to claim 1, wherein the Fe, Ta, N
The information recording medium according to any one of claims 1 to 6, wherein the information recording medium has a structure in which nitride or carbide of at least one element selected from the group consisting of b and Zr is dispersed. 8. The recording auxiliary layer is formed using an amorphous alloy mainly composed of Co-Zr and containing at least one element selected from the group consisting of Ta, Nb and Ti. The information recording medium according to any one of claims 1 to 6, wherein 9. The information recording medium according to claim 7, wherein the seed layer is formed by oxidizing a surface of the recording auxiliary layer. 10. An information recording medium according to claim 1, a magnetic head for recording or reproducing information, and a magnetic head for driving said magnetic recording medium with respect to said magnetic head. An information recording device, comprising: a driving device; 11. A method for manufacturing an information recording medium including a recording holding layer and a seed layer, wherein the seed layer is formed by sputtering Fe using oxygen-containing sputtering gas.
And forming the target by reactive sputtering. 12. The method according to claim 11, wherein the amount of oxygen in the sputtering gas is controlled so that Fe present as a metal is contained in the seed layer. 13. The method according to claim 12, further comprising sputter etching the surface of the seed layer. 14. A method for manufacturing an information recording medium including a recording auxiliary layer containing Fe, a seed layer, and a recording holding layer, wherein after forming the recording auxiliary layer, the surface of the recording auxiliary layer is oxidized at a high temperature. Forming the seed layer.