JP2002269718A - Perpendicular magnetic recording medium and magnetic storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a perpendicular magnetic recording medium having excellent low noise characteristics and stability of recording magnetization and suitable for super high density magnetic recording and to provide a magnetic storage device. SOLUTION: In the perpendicular magnetic recording medium, a perpendicularly magnetized film 20 having a laminated structure consisting of Co/(Pt or Pd) multilayered films 14, 16 and 18 and Co-Xa/(Pt or Pd) multilayered films 15 and 17 (Xa: Cr, B, Ta, Mn, V) or consisting of the Co/(Pt or Pd) multilayered films and Co/(Pt-Ya or Pd-Ya) multilayered films (Ya: B, Ta, Ru, Re, Ir, Mn, Mg, Zr, Nb) is used and an amorphous material or a polycrystalline thin film having a noncolumnar structure is used as a backing layer 12 whose magnetic domain structure is controlled by a magnetic domain fixing layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perpendicular magnetic recording medium and a magnetic storage device which are suitable for ultra-high-density magnetic recording and have low reproduction noise and excellent recording magnetization stability.

[0002]

2. Description of the Related Art In order to improve the linear recording density in the in-plane magnetic recording system currently used practically, the residual magnetization of a magnetic film as a recording medium must be reduced in order to reduce the influence of a demagnetizing field during recording. It is necessary to reduce the product (Br · t) of (Br) and the magnetic film thickness (t) to increase the coercive force. Further, in order to reduce the medium noise generated from the magnetization transition, it is necessary to orient the easy axis of the magnetic film parallel to the substrate surface and to control the crystal grain size.

As a magnetic film for longitudinal magnetic recording, Co is used as a main component and Cr, Ta, Pt, Rh, Pd, T
A Co alloy thin film to which i, Ni, Nb, Hf or the like is added is used. As the Co alloy constituting the magnetic thin film, a material having a hexagonal close-packed lattice structure (hereinafter, referred to as an hcp structure) is mainly used. The c axis of the crystal has an easy axis in the <00.1> direction, and the easy axis is oriented in the in-plane direction. In order to control the crystal orientation and grain size of the magnetic thin film, an underlayer for structure control is formed between the substrate and the magnetic film. The base layer is mainly composed of Cr, and Ti, Mo, V, W, P
A material to which t, Pd, or the like is added is used. The magnetic thin film is formed by a vacuum evaporation method or a sputtering method. As described above, in order to reduce medium noise and improve linear recording density in longitudinal magnetic recording, it is necessary to reduce the product of the residual magnetization (Br) and the magnetic film thickness (t) of the magnetic film. First, the thickness of the magnetic film is reduced to 20 nm or less, and the crystal grain size is reduced to 1 nm.
It is necessary to reduce the size to 0 to 15 nm. However, such a medium in which the magnetic crystal grains are made fine has a very serious problem that the recording magnetization decreases due to thermal fluctuation, which is an obstacle to high-density recording.

On the other hand, the perpendicular magnetic recording system is a magnetic recording system in which magnetic domains are formed perpendicularly to the recording medium surface so that adjacent recording bits are antiparallel to each other. There is an advantage that the smaller the recording density is, the more easily the magnetization can be stably maintained as the recording density is high. This is one of the effective means of the high-density magnetic recording. Perpendicular magnetic recording has an advantage that the magnetic film thickness can be made thicker than in-plane magnetic recording, and that the recording magnetization in a high recording density region can be stably maintained, particularly. In order to improve linear recording density by perpendicular magnetic recording, it is necessary to reduce medium noise generated from magnetic domains having irregular structures formed inside recording bits and in a magnetization transition region. To this end, it is necessary to align the easy axis of the magnetic film perpendicular to the substrate surface, reduce the orientation dispersion of the easy axis, and control the crystal grain size.

[0005] The perpendicular magnetic recording medium includes a single-layer perpendicular magnetic recording medium in which a perpendicular magnetization film is formed on a substrate via a structure control layer, and a soft magnetic film formed on a substrate, on which a structure control layer is formed. There is a two-layer perpendicular magnetic recording medium in which a perpendicular magnetization film is formed through the medium. In the former case, the main cause of the medium noise is a magnetic domain having an irregular structure formed in the recording bit and in the magnetization transition region. On the other hand, in the case of the latter two-layer perpendicular magnetic recording medium, the medium noise is caused by the magnetic domain structure of the soft magnetic film provided below the perpendicular magnetization film in addition to the irregular domain formed inside the recording bit and the magnetization transition region. It is also caused by turbulence.

[0006]

There have been proposed many means for reducing noise and improving the stability of recording magnetization in perpendicular magnetic recording. For example, Digest of the Fourth Perpe
ndicular Magnetic Recording Conference '97 and Digest
of the Fifth Perpendicular Magnetic Recording Con
CoCr alloy / Ti as described in ference 2000
Of the crystal orientation of the CoCr alloy magnetic film by introducing a two-layer underlayer made of CoCrPt-O granular magnetic film, Co / Pt (or Pd) multilayer magnetic film, Te-Fe
A method of improving the squareness ratio of a perpendicular magnetization film by coating a Co / Pt (or Pd) multilayer magnetic film on a -Co amorphous magnetic film or a CoCr alloy magnetic film has been proposed. In a conventional perpendicular magnetization film using a CoCr alloy system, C
Controlling the interaction between magnetic particles by introducing an oCr alloy composition or an additive element such as Ta, B, Nb, or improving the crystal orientation of a CoCr alloy magnetic film by using a seed layer, etc., to reduce medium noise and stabilize magnetization. Improvements were made.

However, in a conventional perpendicular magnetization film using a CoCr alloy system, a technique for simultaneously reducing medium noise and stabilizing magnetization has not been established. Co / Pt (or
Pd) The multilayer magnetic film and the Te—Fe—Co amorphous magnetic film have large perpendicular magnetic anisotropy and excellent magnetization stability. However, there is a disadvantage that is improved. In order to overcome this drawback, in the prior art, a method of forming microscopic undulations in a seed layer, a method of controlling a sputtering gas pressure, or a method of coating a Co / Pt (or Pd) multilayer magnetic film on a CoCr alloy magnetic film. And the like. In these prior arts, the perpendicular magnetic anisotropy dispersion of the Co / Pt (or Pd) multilayer magnetic film is enlarged, which is an obstacle to high-density recording, such as impairing medium noise and magnetization stability.

Although the recording efficiency can be improved by forming a soft magnetic underlayer below the perpendicular magnetization film, noise generated from magnetic domains formed in the soft magnetic layer is also an important issue. As a method for controlling the magnetic domain structure of the soft magnetic film, for example, a method in which an in-plane magnetized film is directly in contact with a lower layer of the soft magnetic film as disclosed in Japanese Patent Application Laid-Open No. 11-191217, "Method for Manufacturing a Perpendicular Magnetic Recording Medium" Has been proposed. According to this method, the effect that the disturbance of the magnetic domain structure of the soft magnetic film due to the external magnetic field can be reduced to some extent is recognized, but by forming the in-plane magnetic film directly in contact with the lower layer of the soft magnetic film, the in-plane magnetic film can be reduced. The disturbance of the magnetic domain structure is transferred to the soft magnetic film thereon, and as a result, there is a problem that noise generated from the soft magnetic film is included in the reproduction signal of the perpendicular magnetization film, which causes an obstacle to high-density recording.

In order to realize ultra-high-density magnetic recording with a perpendicular magnetic recording medium composed of a Co / Pt or Co / Pd multilayer film having excellent perpendicular magnetic anisotropy, not only the linear recording density is improved but also the reproduction signal is included. It is important to reduce the medium noise and to keep the recording magnetization stable. In a perpendicular magnetic recording medium, the perpendicular magnetic film as a recording layer has a large perpendicular magnetic anisotropy to overcome the demagnetizing field, has a squareness ratio in the direction perpendicular to the film surface infinitely close to 1, and has a negative nucleation field. Value, the interaction between the magnetic particles is moderately controlled and the magnetic domain size when recording at high density is small,
It is desirable to reduce medium noise and signal degradation.

The present invention has been made in view of such a problem.
It is an object of the present invention to provide a perpendicular magnetic recording medium and a magnetic storage device that have excellent low noise characteristics and stable recording magnetization and that are suitable for ultra-high-density magnetic recording while solving the drawbacks of the prior art.

[0011]

Means for Solving the Problems The present inventors have proposed Co / P
The present inventors have found a perpendicular magnetization film suitable for ultra-high-density magnetic recording which has low noise characteristics and excellent recording magnetization stability without impairing the excellent perpendicular magnetic anisotropy of the t multilayer film or the Co / Pd multilayer film. It was completed.

That is, a perpendicular magnetic recording medium according to the present invention is a perpendicular magnetic recording medium comprising a perpendicular magnetic film including a Co / Pt or Co / Pd multilayer film, wherein Co-Xa / Pt or Co -Xa / Pd multilayer film layer (X
a is at least one element selected from the group consisting of Cr, B, Ta, Mn, and V).

[0013] The perpendicular magnetic recording medium according to the present invention also includes:
In a perpendicular magnetic recording medium composed of a perpendicular magnetic film including a Co / Pt or Co / Pd multilayer film, C
o / Pt-Ya or Co / Pd-Ya multilayer film layer (Ya is B, Ta, Ru, Re, Ir, Mn, Mg, Zr, Nb
At least one element selected from the group consisting of:

In the Co—Xa / Pt or Co—Xa / Pd multilayer film, the additive element Xa (Xa: Cr, B, Ta,
Mn, V) has the effect of controlling the magnetic interaction between Co particles, and also Co / Pt-Ya or Co / Pd-Y
aAdditional element Ya (Ya: B, Ta, R) in a multilayer film layer
u, Re, Ir, Mn, Mg, Zr, Nb) have the effect of controlling the crystal grain size of the Pt layer or Pd layer. This gives C
An ultra-high-performance film that controls the magnetic interaction between magnetic grains and maintains excellent low-noise characteristics and stable recording magnetization without impairing the excellent perpendicular magnetic anisotropy inherent in the o / Pt multilayer film or the Co / Pd multilayer film. A perpendicular magnetic recording medium suitable for high-density magnetic recording is obtained.
The perpendicular magnetic recording medium may have a soft magnetic layer below the perpendicular magnetic film, or may have a non-magnetic intermediate layer between the soft magnetic layer and the perpendicular magnetic film.

The soft magnetic layer is made of Co-Zr-Xb (Xb is T
at least one selected from a, Nb, Mo, W, and Ni
Non-columnar polycrystals such as an amorphous alloy film of Fe-Al-Si alloy, Fe-C-Yc (Yc is at least one element selected from Ta, Hf, Zr, and Nb) alloys It is preferable to be composed of any of a film and a Ni—Fe alloy.

Further, in the perpendicular magnetic recording medium provided with the above-described soft magnetic underlayer, one side of the perpendicular magnetic film is
IrMn, PtMn,
It has been found that spike noise generated from the soft magnetic film can be reduced by providing an antiferromagnetic layer film such as PtCrMn.

In the perpendicular magnetic recording medium according to the present invention, as an example, soft magnetic layers are provided on both surfaces of an antiferromagnetic layer disposed immediately below a perpendicular magnetization film to provide a flux return path for a leakage magnetic field from a recording head during magnetic recording. A structure in which a recording layer is formed to improve recording efficiency, a structure in which a non-magnetic intermediate layer is disposed between the soft magnetic layer immediately below the perpendicular magnetic film and the perpendicular magnetic film, and a Co-
Zr-Xb (Xb: Ta, Nb, Mo, W, Ni) amorphous alloy film, or Fe-Al-Si alloy or Fe-C
A configuration is employed in which a non-columnar polycrystalline film such as -Yc (Yc: Ta, Hf, Zr, Nb) alloy or a soft magnetic layer of Ni-Fe alloy is provided on one or both surfaces of the antiferromagnetic layer.

A magnetic storage device according to the present invention comprises a magnetic recording medium, a ring or single pole type magnetic recording head, and a magnetoresistive, spin valve or magnetic tunnel type signal reproducing head. In the storage device, the above-described perpendicular magnetic recording medium is used as the perpendicular magnetic recording medium.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. In the figure, the portions denoted by the same reference numerals indicate portions having the same performance characteristics. FIG. 1 is a schematic sectional view showing an example of the basic structure of a perpendicular magnetic recording medium according to the present invention. Although the perpendicular magnetic recording medium according to the present invention can be used with a perpendicular medium having no underlying soft magnetic layer in the lower layer, the perpendicular magnetic recording medium according to the present invention uses the two-layer perpendicular magnetic recording medium shown in FIG. Explain the contents.

The perpendicular magnetic recording medium of the present invention is formed by forming a soft magnetic underlayer 12, a non-magnetic intermediate layer 13, a multilayer perpendicular magnetic film 20, and a protective layer 19 on a substrate 11. As the substrate 11, a Si disk substrate other than a glass substrate,
An NiP-coated aluminum substrate, a carbon substrate, a polymer substrate, or the like is used. The soft magnetic underlayer 12 is made of Co
-Zr-Xb (Xb: Ta, Nb, Mo, W, Ni) based amorphous alloy film, or Fe-Al-Si alloy or Fe-
In order to control the magnetic domain structure of the backing soft magnetic layer by using a non-columnar polycrystalline film such as a C-Yc (Yc: Ta, Hf, Zr, Nb) alloy or a soft magnetic film of a Ni-Fe alloy. I
An antiferromagnetic layer film such as rMn, PtMn, PtCrMn is provided.

The antiferromagnetic layer film is used to suppress the formation of magnetic domains in the soft magnetic underlayer and to prevent the occurrence of spike noise. The antiferromagnetic layer film is desirably provided at a distance of 10 to 200 nm from the lower surface of the perpendicular magnetization film 20. The non-magnetic intermediate layer 13 is generated from the backing soft magnetic layer by weakening the magnetic interaction between the perpendicular magnetization film and the backing soft magnetic layer in addition to controlling the crystal orientation and crystal grain size of the perpendicular magnetization film formed thereon. This has the effect of reducing noise.
As the nonmagnetic intermediate layer 13, for example, a TiCr alloy, CoC
r alloy, NiTaZr alloy, Ti, or Si, G
e, C, amorphous thin film, Pt, Pd, Ru thin film, I
A TO (Indium Tin Oxide) thin film or the like can be used. The thickness of the non-magnetic intermediate layer 13 is 1 to 5 nm.

The perpendicular magnetization film 20 is formed of a Co / Pt multilayer film or Co / Pd multilayer films 14, 16, 18 and Co-Xa / P
t, Co-Xa / Pd (Xa: Cr, B, Ta, Mn,
V) or Co / Pt-Ya, Co / Pd-Ya (Ya:
B, Ta, Ru, Re, Ir, Mn, Mg, Zr, N
b) A laminated structure with multilayer films 15 and 17 selected from multilayer films. Co-Xa / Pt, Co-Xa / Pd (X
a: Cr, B, Ta, Mn, V) The additive (Xa: Cr, B, Ta, Mn, V) in the multilayer film has the effect of controlling the particle diameter of the Co layer and promoting the isolation of the magnetic particles. is there. Co / Pt-Ya, Co / Pd-Ya (Ya: B, T
a, Ru, Re, Ir, Mn, Mg, Zr, Nb) Additives in a multilayer film (Ya: B, Ta, Ru, Re, I)
(r, Mn, Mg, Zr, Nb) have the effect of controlling the particle diameter of the Pt layer or Pd layer and promoting the isolation of magnetic particles.

According to the present invention, Co / Pt, Co / Pd multilayer film and Co-Xa / Pt, Co-Xa / Pd, Co / P
By using a perpendicular magnetization film having a laminated structure with any of the t-Ya and Co / Pd-Ya multilayer films, the conventional Co / Pt
Alternatively, low noise and high magnetization stability can be realized as compared with a Co / Pd multilayer perpendicular magnetization film. The magnitude of the magnetization of the perpendicular magnetization film can be arbitrarily changed by changing the lamination ratio.

The outline of the magnetic storage device used for evaluating the recording and reproducing characteristics of the medium according to the present invention will be described with reference to FIG. The magnetic storage device includes a magnetic disk 31, a magnetic head 32 for recording and reproduction, a suspension 33 supporting the magnetic head, an actuator 34, a voice coil motor 35, a recording and reproduction circuit 36, a positioning circuit 37, an interface control circuit 38, and the like. You. The magnetic disk 31 is shown in FIG.
And a lubricating film is coated on the protective film. The magnetic head 32 is composed of a slider, a magnetic recording head provided thereon, and a reproducing head composed of a magnetoresistive, giant magnetoresistive or spin-valve element or a magnetic tunnel element for reproducing signals. You. The gap length of the magnetic head for reproducing the recording signal is set at 0.
25 μm or less, preferably 0.08 to 0.15 μm
And As a magnetic recording head, a ring type head or a single pole type head was used. The track width of the playback head is
The recording head magnetic pole is made narrower than the track width to reduce reproduction noise generated from both ends of the recording track. The magnetic head 32 is supported by the suspension 33. Using this apparatus, medium noise characteristics and recording / reproduction characteristics evaluation described in the following examples were performed.

Example 1 The contents of a perpendicular magnetic recording medium of the present invention are shown in FIG.
This will be described below with reference to FIG.

A medium A was prepared by the following method. The washed glass substrate 11 was set in a high vacuum DC magnetron sputtering apparatus, and after heating the substrate to 250 ° C., a Ta layer having a thickness of 5 nm was formed as a precoat layer. The precoat layer is used to increase the adhesion strength between the thin film formed thereon and the substrate. On this precoat layer, a film thickness of 10 n
m of the non-magnetic intermediate layer 13 was formed. As the nonmagnetic intermediate layer 13, a Pd film was used.

Subsequently, [Pd (0.75 nm) / Co
(0.25 nm)]. The film having this configuration is hereinafter referred to as [Pd (0.75 nm) / Co
(0.25 nm)] × 4 multilayer film. Furthermore, [Pd
(0.75 nm) / Co-Mn (0.25 nm)] × 4
The multilayer film 15, [Pd (0.75 nm) / Co (0.25 nm)
nm)] × 4 multilayer film 16, [Pd (0.75 nm) / C
o-Mn (0.25 nm)] × 4 multilayer film 17, [Pd
(0.75 nm) / Co (0.25 nm)] × 4 multilayer films 18 were stacked to form a perpendicular magnetization film 20 having a total thickness of 20 nm. Here, [Pd (0.75 nm) / Co
-Mn (0.25 nm)] × 4 multilayer film 15, [Pd
(0.75 nm) / Co-Mn (0.25 nm)] × 4
In the multilayer film 17, the addition amount of Mn in the Co-Mn layer was set in a range of 2 to 10 at%, and in this embodiment, 5 at%. Any of Cr, B, Ta, and V can be used instead of Mn. A medium A was formed by forming a C protective layer 19 having a thickness of 5 nm on the surface of the perpendicular magnetization film 20.

When the structure of the perpendicular magnetization film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pd and Co were detected. As a result of measuring the magnetic properties of the medium A in the direction perpendicular to the film surface with a Kerr effect magnetometer, the coercive force was 3.
7 kOe, nucleation field Hn =-
The squareness ratio SQ was 1.2 kOe. Here, the nucleation field Hn is defined by the magnetic field strength at the intersection of the tangent to the coercive force and the extension of the saturation magnetization in the magnetization magnetic field curve. The squareness ratio SQ is determined by the residual magnetization Mr
And the ratio Mr / Ms of the saturation magnetization Ms.

A medium B was prepared by the following method. The washed glass substrate 11 was set in a high vacuum DC magnetron sputtering apparatus, and after heating the substrate to 250 ° C., a Ta layer having a thickness of 5 nm was formed as a precoat layer. The precoat layer is used to increase the adhesion strength between the thin film formed thereon and the substrate. On this precoat layer, a film thickness of 10 n
m of the non-magnetic intermediate layer 13 was formed. As the nonmagnetic intermediate layer 13, a Pd film was used.

Subsequently, [Pd (0.75 nm) / Co
(0.25 nm)] × 4 was formed. Further, [Pd-B (0.75 nm) / Co (0.25 nm)
nm)] × 4 multilayer film 15, [Pd (0.75 nm) / C
o (0.25 nm)] × 4 multilayer film 16, [Pd-B
(0.75 nm) / Co (0.25 nm)] × 4 multilayer film 17, [Pd (0.75 nm) / Co (0.25 n)
m)] The total film thickness 20 of the configuration in which the × 4 multilayer films 18 are stacked in this order.
The perpendicular magnetization film 20 of nm was manufactured. Here [Pd-B
(0.75 nm) / Co (0.25 nm)] × 4 multilayer film 15, [Pd-B (0.75 nm) / Co (0.25 n)
m)] In the × 4 multilayer film 17, the addition amount of B in the Pd—B layer is in the range of 2 to 10 at%, and is 5 at in the present embodiment.
%. Ta, Ru, Re, Ir, M instead of B
It is also possible to use any of n, Mg, Zr, and Nb. A medium B was formed by forming a 5 nm-thick C protective layer 19 on the surface of the perpendicular magnetization film 20.

When the structure of the perpendicular magnetic film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pd and Co were detected. As a result of measuring the magnetic properties of the medium B in the direction perpendicular to the film surface using a Kerr effect magnetometer, the coercive force was 3.
8 kOe, nucleation field Hn =-
1.1 kOe and squareness ratio SQ = 1.

A comparative medium C was prepared. The washed glass substrate 11 was set in a high vacuum DC magnetron sputtering apparatus, and after heating the substrate to 250 ° C., a Ta layer having a thickness of 5 nm was formed as a precoat layer. The pre-coat layer
It is used to increase the adhesion strength between the thin film formed thereon and the substrate. A nonmagnetic intermediate layer 13 having a thickness of 10 nm was formed on the precoat layer. As the nonmagnetic intermediate layer 13, a Pd film was used. Subsequently, [Pd (0.75n
m) / Co (0.25 nm)] × 20 to form a perpendicular magnetization film 20 having a total thickness of 20 nm and a multilayer structure. A comparative medium C was formed by forming a C protective layer 19 having a thickness of 5 nm on the surface of the perpendicular magnetization film 20.

When the structure of the perpendicular magnetization film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pd and Co were detected. As a result of measuring the magnetic properties of the medium C in the direction perpendicular to the film surface using a Kerr effect magnetometer, the coercive force was 3.
2 kOe, nucleation field Hn =-
1.8 kOe and squareness ratio SQ = 1.

A comparative medium D was prepared. The washed glass substrate 11 was set in a high vacuum DC magnetron sputtering apparatus, and after heating the substrate to 250 ° C., a Ta layer having a thickness of 5 nm was formed as a precoat layer. The pre-coat layer
It is used to increase the adhesion strength between the thin film formed thereon and the substrate. A nonmagnetic intermediate layer 13 having a thickness of 10 nm was formed on the precoat layer. As the nonmagnetic intermediate layer 13, a Pt film was used. Subsequently, [Pt (0.75n
m) / Co (0.25 nm)] × 20 to form a perpendicular magnetization film 20 having a total thickness of 20 nm and a multilayer structure. A comparative medium D in which a 5 nm-thick C protective layer 19 was formed on the surface of the perpendicular magnetization film 20 was produced.

When the structure of the perpendicular magnetization film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pt and Co were detected. As a result of measuring the magnetic properties of the medium D in the direction perpendicular to the film surface with a Kerr effect magnetometer, the coercive force was 3.
0 kOe, nucleation field Hn =-
1.7 kOe and squareness ratio SQ = 1.

A comparative medium E using a CoCrPt alloy as a perpendicular magnetization film was manufactured. The washed glass substrate 11 is set in a high vacuum DC magnetron sputtering apparatus,
After heating the substrate to 300 ° C., a nonmagnetic intermediate layer 13 having a thickness of 10 nm was formed. As the non-magnetic intermediate layer 13, Ni-
A 30 at% Ta-5 at% Zr film was used. Successively, a film thickness 2 of Co-22 at% Cr-14 at% Pt
A perpendicular magnetization film 20 having a thickness of 0 nm was formed. The perpendicular magnetization film 2
On the surface of No. 0, a C protective layer 19 having a thickness of 5 nm was formed to obtain a comparative medium E.

When the structure of the perpendicular magnetization film 20 was measured by X-ray diffraction, a diffraction peak of a <002> -oriented CoCrPt alloy was detected. As a result of measuring the magnetic properties of the medium E in the direction perpendicular to the film surface using a Kerr effect magnetometer, the coercive force was 3.0 kOe, and the nucleation field Hn was measured.
= 0.5 kOe and squareness ratio SQ = 0.95. Table 1 shows the characteristics of the medium A, the medium B, the medium C, the medium D, and the medium E.
Is shown in comparison with.

[0038]

[Table 1]

In Table 1, the noise is the ratio to the medium E using the CoCrPt alloy perpendicular magnetization film, and the SNR is 40.
The signal-to-noise ratio at 0 kFCI and the magnetic domain size were recorded as the average diameter of irregular magnetic domains obtained by measuring the magnetic domain structure on the sample surface subjected to AC erasing with a magnetic force microscope (MFM), and the signal degradation rate was recorded at 10 kFCI. And the ratio of the signal intensity after 1 × 10 ⁶ seconds to the signal immediately after recording. The smaller the magnetic domain size, the more suitable the medium for high density recording.
D ₅₀ is used as an index of the recording resolution, and is a linear recording density at which a signal output becomes 50% of a signal output at a low recording density. The larger this value, the better the performance.

Using the magnetic recording apparatus described with reference to FIG. 2, magnetic recording was performed on the medium with a ring-type magnetic head having a track width of 0.2 m, and reproduction was performed with a giant magnetoresistive head (GMR head) having a shield interval of 80 nm. Media noise and recording resolution were measured. The spacing during recording and reproduction was 16 nm. The magnetic domain structure on the surface of the medium after AC erasing was observed with a magnetic force microscope, and the size of the irregular magnetic domains formed on the surface was measured. Here, the sizes of the irregular magnetic domains were compared by the diameter when approximated to a circle having the same area. The larger the diameter of the irregular magnetic domain, the greater the medium noise and the lower the recording resolution.

As is clear from the comparison in Table 1, CoCr
The conventional medium E using the Pt perpendicular magnetization film has a relatively small magnetic domain size and relatively excellent recording resolution and SNR characteristics, but has a disadvantage of a large signal deterioration rate. Co / Pd
Conventional media C and D using a multilayer film or a Co / Pt multilayer film have large perpendicular magnetic anisotropy, excellent SQ characteristics and Hn characteristics, and a small signal deterioration rate, but have poor recording resolution characteristics and SNR characteristics. . On the other hand, the mediums A and B of the present invention have large perpendicular magnetic anisotropy, excellent SQ characteristics and Hn characteristics, a small signal degradation rate, and moderately controlled interaction between magnetic particles. Small, medium noise, SNR
It can be seen that the characteristics and the recording resolution characteristics are excellent.

Using a vibrating sample magnetometer (VSM), the dependence of the magnetic properties (coercive force) on the applied magnetic field direction was measured for the medium A, medium B, medium C, medium D, and medium E, and the results were compared. Is shown in FIG. The horizontal axis in the figure indicates the inclination angle (θ) from the direction perpendicular to the film surface of the sample. The vertical axis is the inclination angle (θ)
The ratio Hc (θ) / Hc of the coercive force Hc (θ) measured in the above to the coercive force Hc (⊥) measured in the direction perpendicular to the film surface.
(⊥). The behavior of the magnetic properties (coercive force) depending on the direction of the applied magnetic field is used as a means for evaluating the magnetic isolation of magnetic particles in a measurement sample.

The medium E is a sample in which the magnetic isolation of the magnetic particles is promoted by adding a high concentration of Cr to the CoCrPt perpendicular magnetization film. The medium E has a small medium noise and indicates that the magnetization rotation type magnetization reversal is performed. On the other hand, the Co / Pd multilayer film (medium C) and the Co / Pt multilayer film (medium D) perpendicular media have large angle dependence of coercive force, large media noise, strong interaction between magnetic particles, and domain wall displacement type magnetization reversal. You are. On the other hand, the medium A and the medium B of the present invention are
It is evident that the magnetic isolation of the magnetic particles was greatly improved as compared with the case of, and the stability of magnetization was improved together with the reduction of the medium noise.

Embodiment 2 The contents of a perpendicular magnetic recording medium according to the present invention will be described below with reference to FIG. 1 using a perpendicular magnetic film having a soft magnetic layer provided on the back surface as an example. The medium F was produced as follows. The cleaned glass substrate 11 having a diameter of 2.5 inches is placed in a high vacuum DC magnetron sputtering apparatus, and the substrate is heated to 250 ° C., and then has a thickness of 5 n as a precoat layer.
m Ta layers were formed. The precoat layer is used to increase the adhesion strength between the thin film formed thereon and the substrate.
50 at% Ir-M having a thickness of 20 nm on the pre-coat layer
n-1 antiferromagnetic film, 200 nm-thick amorphous Co-1
Backing soft magnetic layer 1 of 0 at% Ta-2 at% Zr
2 was formed. During the formation of the thin film, a magnetic field of about 300 Gauss was applied in the radial direction of the disk to give the backing soft magnetic layer 12 a magnetic anisotropy in the radial direction. A nonmagnetic intermediate layer 13 having a thickness of 5 nm was formed on the soft magnetic underlayer 12. As the nonmagnetic intermediate layer 13, a Pd-5 at% B film was used.

Subsequently, [Pd (0.75 nm) / Co
(0.25 nm)] × 4 was formed. Further, [Pd (0.75 nm) / Co-B (0.25 nm)
nm)] × 4 multilayer film 15, [Pd (0.75 nm) / C
o (0.25 nm)] × 4 multilayer film 16, [Pd (0.7
5 nm) / Co-B (0.25 nm)] × 4 multilayer film 1
7, [Pd (0.75 nm) / Co (0.25 nm)]
A perpendicular magnetization film 20 having a total thickness of 20 nm and a configuration in which the × 4 multilayer films 18 were stacked in this order was manufactured. Here, [Pd (0.75n
m) / Co—B (0.25 nm)] × 4, the amount of B added in the Co—B layer was in the range of 2 to 10 at%, and was 5 at% in the present embodiment. C instead of B
It is also possible to use any of r, Mn, Ta, and V. A medium F was formed by forming a C protective layer 19 having a thickness of 5 nm on the surface of the perpendicular magnetization film 20.

When the structure of the perpendicular magnetic film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pd and Co were detected. As a result of measuring the magnetic properties of the medium F in the direction perpendicular to the film surface using a Kerr effect magnetometer, the coercive force was measured.
3 kOe, nucleation field Hn =-
The squareness ratio SQ was 1.2 kOe.

A medium G was prepared. The cleaned glass substrate 11 having a diameter of 2.5 inches was placed in a high vacuum DC magnetron sputtering apparatus, and after heating the substrate to 250 ° C., a Ta layer having a thickness of 5 nm was formed as a precoat layer. The precoat layer is used to increase the adhesion strength between the thin film formed thereon and the substrate. A film thickness of 20 on the precoat layer
50 at% Ir-Mn antiferromagnetic film with a thickness of 200 nm
Co-10at% Ta-2at% Zr having an amorphous structure of m
A soft magnetic underlayer 12 made of During the formation of the thin film, a magnetic field of about 300 Gauss was applied in the radial direction of the disk to give the backing soft magnetic layer 12 a magnetic anisotropy in the radial direction.
Non-magnetic intermediate layer 1 having a thickness of 5 nm on soft magnetic under layer 12
3 was formed. As the non-magnetic intermediate layer 13, Pd-5a
A t% B film was used.

Subsequently, [Pd (0.75 nm) / Co
(0.25 nm)] × 4 was formed. Further, [Pd-B (0.75 nm) / Co (0.25 nm)
nm)] × 4 multilayer film 15, [Pd (0.75 nm) / C
o (0.25 nm)] × 4 multilayer film 16, [Pd-B
(0.75 nm) / Co (0.25 nm)] × 4 multilayer film 17, [Pd (0.75 nm) / Co (0.25 n)
m)] The total film thickness 20 of the configuration in which the × 4 multilayer films 18 are stacked in this order.
The perpendicular magnetization film 20 of nm was manufactured. Here [Pd-B
(0.75 nm) / Co (0.25 nm)] × 4, the addition amount of B in the Pd—B layer is in the range of 2 to 10 at%, and is 5 at% in the present embodiment. T instead of B
It is also possible to use any of a, Ru, Re, Ir, Mn, Mg, Zr, and Nb. A medium G was formed by forming a C protective layer 19 having a thickness of 5 nm on the surface of the perpendicular magnetization film 20.

When the structure of the perpendicular magnetization film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pd and Co were detected. As a result of measuring the magnetic properties of the medium G in the direction perpendicular to the film surface with a Kerr effect magnetometer, the coercive force was measured.
2 kOe, nucleation field Hn =-
1.1 kOe and squareness ratio SQ = 1.

A comparative medium H was prepared. The cleaned glass substrate 11 having a diameter of 2.5 inches was placed in a high vacuum DC magnetron sputtering apparatus, and after heating the substrate to 250 ° C., a Ta layer having a thickness of 5 nm was formed as a precoat layer. The precoat layer is used to increase the adhesion strength between the thin film formed thereon and the substrate. On the precoat layer, a 50 at% Ir-Mn antiferromagnetic film having a thickness of 20 nm, and an amorphous Co-10 at% Ta-2a film having a thickness of 200 nm.
A backing soft magnetic layer 12 of t% Zr was formed. During the formation of the thin film, a magnetic field of about 300 Gauss was applied in the radial direction of the disk to give the backing soft magnetic layer 12 a magnetic anisotropy in the radial direction. A nonmagnetic intermediate layer 13 having a thickness of 5 nm was formed on the soft magnetic underlayer 12. As the non-magnetic intermediate layer 13, P
d film was used.

Subsequently, [Pd (0.75 nm) / Co
(0.25 nm)] A perpendicular magnetization film 20 having a total thickness of 20 nm and a multilayer structure of × 20 was formed. The perpendicular magnetization film 2
On the surface of No. 0, a C protective layer 19 having a thickness of 5 nm was formed to obtain a comparative medium H. When the structure of the perpendicular magnetization film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pd and Co were detected. As a result of measuring the magnetic properties of the medium H in the direction perpendicular to the film surface using a Kerr effect magnetometer, the coercive force was 3.3 kOe, and the nucleation field Hn =
-1.7 kOe and squareness ratio SQ = 1.

A comparative medium I was prepared. The cleaned glass substrate 11 having a diameter of 2.5 inches was placed in a high vacuum DC magnetron sputtering apparatus, and after heating the substrate to 250 ° C., a Ta layer having a thickness of 5 nm was formed as a precoat layer. The precoat layer is used to increase the adhesion strength between the thin film formed thereon and the substrate. On the precoat layer, a 50 at% Ir-Mn antiferromagnetic film having a thickness of 20 nm, and an amorphous Co-10 at% Ta-2a film having a thickness of 200 nm.
A backing soft magnetic layer 12 of t% Zr was formed. During the formation of the thin film, a magnetic field of about 300 Gauss was applied in the radial direction of the disk to give the backing soft magnetic layer 12 a magnetic anisotropy in the radial direction. A nonmagnetic intermediate layer 13 having a thickness of 5 nm was formed on the soft magnetic underlayer 12. As the non-magnetic intermediate layer 13, P
A t film was used. Subsequently, [Pt (0.75 nm) / C
o (0.25 nm)] × 20, and a perpendicular magnetization film 20 having a total film thickness of 20 nm having a multilayer structure was formed. A C protective layer 19 having a thickness of 5 nm was formed on the surface of the perpendicular magnetization film 20 to obtain a comparative medium I.

When the structure of the perpendicular magnetic film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pt and Co were detected. As a result of measuring the magnetic properties of the medium I in the direction perpendicular to the film surface using a Kerr effect magnetometer, the coercive force was 3.
2 kOe, nucleation field Hn =-
1.6 kOe and squareness ratio SQ = 1.

A comparative medium J using a CoCrPt alloy as the perpendicular magnetization film was manufactured. The cleaned glass substrate 11 having a diameter of 2.5 inches was placed in a high vacuum DC magnetron sputtering apparatus, and after heating the substrate to 250 ° C., a Ta layer having a thickness of 5 nm was formed as a precoat layer. The precoat layer is used to increase the adhesion strength between the thin film formed thereon and the substrate. 20 nm thick on the pre-coat layer
And a backing soft magnetic layer 12 of Co-10 at% Ta-2 at% Zr having an amorphous structure and a thickness of 200 nm was formed. About 30 during thin film formation
A magnetic field of 0 Gauss was applied in the radial direction of the disk to impart a magnetic anisotropy in the radial direction to the soft magnetic underlayer 12. After heating the substrate to 300 ° C., a nonmagnetic intermediate layer 13 having a thickness of 5 nm was formed on the soft magnetic underlayer 12. Non-magnetic intermediate layer 1
As No. 3, a Ni-30 at% Ta-5 at% Zr film was used. Subsequently, Co-22 at% Cr-14 at%
A 20-nm-thick perpendicular magnetization film 20 made of Pt was formed. A C protective layer 19 having a thickness of 5 nm was formed on the surface of the perpendicular magnetization film 20 to obtain a comparative medium J.

When the structure of the perpendicular magnetization film 20 was measured by X-ray diffraction, a diffraction peak of a <002> -oriented CoCrPt alloy was detected. As a result of measuring the magnetic properties of the medium E in the direction perpendicular to the film surface with a Kerr effect magnetometer, the coercive force was 3.1 kOe and the nucleation field Hn
= 0.5 kOe and squareness ratio SQ = 0.94. Table 2 shows the characteristics of medium F, medium G, medium H, medium I, and medium J.
Is shown in comparison with.

[0056]

[Table 2]

In Table 2, the noise is the ratio to the medium J using the CoCrPt alloy perpendicular magnetization film, and the SNR is 40.
The signal-to-noise ratio at 0 kFCI and the magnetic domain size were recorded as the average diameter of irregular magnetic domains obtained by measuring the magnetic domain structure on the sample surface subjected to AC erasing with a magnetic force microscope (MFM), and the signal degradation rate was recorded at 10 kFCI. And the ratio of the signal intensity after 1 × 10 ⁶ seconds to the signal immediately after recording. The smaller the magnetic domain size, the more suitable the medium for high density recording. D ₅₀ is used as an index of the recording resolution, and is a linear recording density at which a signal output becomes 50% of a signal output at a low recording density. The larger this value, the better the performance.

Using the magnetic recording apparatus described with reference to FIG. 2, magnetic recording was performed on the medium with a single pole type magnetic head having a track width of 0.2 m, and reproduction was performed with a giant magnetoresistive head (GMR head) having a shield interval of 80 nm. Media noise and recording resolution were measured. The spacing during recording and reproduction was 16 nm. The magnetic domain structure on the surface of the medium after AC erasing was observed with a magnetic force microscope, and the size of the irregular magnetic domains formed on the surface was measured. Here, the sizes of the irregular magnetic domains were compared by the diameter when approximated to a circle having the same area. The larger the diameter of the irregular magnetic domain, the greater the medium noise and the lower the recording resolution.

As is clear from the comparison of Table 2, CoCr
The conventional medium J using the Pt perpendicular magnetization film has a relatively small magnetic domain size and relatively excellent recording resolution and SNR characteristics, but has a disadvantage of a large signal deterioration rate. Co / Pd
Conventional media H and I using a multilayer film or a Co / Pt multilayer film have large perpendicular magnetic anisotropy, excellent SQ characteristics and Hn characteristics, and a small signal deterioration rate, but have poor recording resolution characteristics and SNR characteristics. . On the other hand, the mediums F and G of the present invention have large perpendicular magnetic anisotropy, excellent SQ characteristics and Hn characteristics, a small signal deterioration rate, and moderately controlled interaction between magnetic particles. Small, medium noise, SNR
It can be seen that the characteristics and the recording resolution characteristics are excellent.

Further, it is difficult for the comparative medium having the conventional medium configuration to simultaneously reduce the medium noise, improve the recording resolution, and stabilize the magnetization, but the medium of the present invention has a coercive force, nucleation, and nucleation. The magnetic properties such as field, squareness ratio, magnetic isolation, etc. can be greatly improved, and it is possible to simultaneously reduce medium noise, improve recording resolution, and greatly improve magnetization stability. Also, by realizing high coercive force and high squareness ratio, linear recording density from 5 kFCI to 400 kFC
It was found that long-term magnetization stability can be maintained in the wide recording density region of I.

Embodiment 3 Another application example of the perpendicular magnetic recording medium of the present invention having the medium configuration shown in FIG. 1 will be described below.
In the present embodiment, the Co / (Pt, or Pd) multilayer film
-Xa / (Pt, or Pd)
(Pt, or Pd) Multilayer film and Co / (Pt-Ya, or Pd)
d-Ya) A medium in which the lamination ratio of the multilayer film was changed was used.
Here, a perpendicular magnetization film in which the stacking ratio of the Co / Pd multilayer film and the Co-Xa / Pd multilayer film (Xa is V) is changed, and Co / P
A perpendicular magnetization film in which the stacking ratio of the d multilayer film and the Co / Pd-Ya multilayer film (Ya is B) is changed will be described as an example.

A cleaned glass substrate 1 having a diameter of 2.5 inches
1 was placed in a high-vacuum DC magnetron sputtering apparatus, the substrate was heated to 250 ° C., and a 5 nm-thick Ta layer was formed as a precoat layer. The precoat layer is used to increase the adhesion strength between the thin film formed thereon and the substrate. 50 at% I of 20 nm thickness on the pre-coat layer
r-Mn antiferromagnetic film, 200 nm thick amorphous C
A backing soft magnetic layer 12 made of o-10 at% Ta-2 at% Zr was formed. During the formation of the thin film, a magnetic field of about 300 Gauss was applied in the radial direction of the disk to give the backing soft magnetic layer 12 a magnetic anisotropy in the radial direction. Backing soft magnetic layer 12
A non-magnetic intermediate layer 13 having a thickness of 5 nm was formed on the substrate. As the nonmagnetic intermediate layer 13, a Pd-5 at% B film was used.

Subsequently, [Pd (0.75 nm) / Co
(0.25 nm)] × m multilayer film 14, [Pd (0.75 nm)
nm) / Co-V (0.25 nm)] × n multilayer film 15,
[Pd (0.75 nm) / Co (0.25 nm)] × m
The multilayer film 16, [Pd (0.75 nm) / Co-V (0.
25 nm)] × n multilayer film 17 and [Pd (0.75 n
m) / Co (0.25 nm)] × m multilayer film 18 was stacked in this order to produce a perpendicular magnetization film 20 having a total film thickness of 20 nm. m and n are the number of layers of the multilayer film.

Here, [Pd (0.75 nm) / Co
(0.25 nm)] layer number m and [Pd (0.75n)
m) / Co-V (0.25 nm)], the stacking ratio was changed by changing the number n of layers. Also, [Pd (0.75n
m) / Co-V (0.25 nm)] layer.
Samples were prepared in which the V addition amount of the film was changed to 3 at%, 5 at%, and 8 at%. A film thickness of 5 on the surface of the perpendicular magnetization film 20
A medium having a C protective layer 19 of nm was formed.

When the structure of the perpendicular magnetic film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pd and Co were detected. As a result of measuring the magnetic properties of the medium in the direction perpendicular to the film surface using a Kerr effect magnetometer, the coercive force was 4.3.
ニ ュ ー 3.8 kOe, nucleation field Hn = −1.3 to −1.1 kOe, squareness ratio SQ = 1１〜
The range was 0.98.

The cleaned glass substrate 1 having a diameter of 2.5 inches
1 was placed in a high-vacuum DC magnetron sputtering apparatus, the substrate was heated to 250 ° C., and a 5 nm-thick Ta layer was formed as a precoat layer. The precoat layer is used to increase the adhesion strength between the thin film formed thereon and the substrate. 50 at% I of 20 nm thickness on the pre-coat layer
r-Mn antiferromagnetic film, 200 nm thick amorphous C
A backing soft magnetic layer 12 made of o-10 at% Ta-2 at% Zr was formed. During the formation of the thin film, a magnetic field of about 300 Gauss was applied in the radial direction of the disk to give the backing soft magnetic layer 12 a magnetic anisotropy in the radial direction. Backing soft magnetic layer 12
A non-magnetic intermediate layer 13 having a thickness of 5 nm was formed on the substrate. As the nonmagnetic intermediate layer 13, a Pd-5 at% B film was used.

Subsequently, [Pd (0.75 nm) / Co
(0.25 nm)] × m multilayer film 14, [Pd-B (0.
75 nm) / Co (0.25 nm)] × n multilayer film 15,
[Pd (0.75 nm) / Co (0.25 nm)] × m
The multilayer film 16, [Pd-B (0.75 nm) / Co (0.
25 nm)] × n multilayer film 17, [Pd (0.75 nm)
/ Co (0.25 nm)] × m multilayer film 18 was stacked in this order to produce a perpendicular magnetization film 20 having a total thickness of 20 nm.

Here, [Pd (0.75 nm) / Co
(0.25 nm)] layer number m and [Pd-B (0.75 nm)
nm) / Co (0.25 nm)] layer, the stacking ratio was changed. In addition, [Pd-B (0.75
nm) / Co (0.25 nm)] layer, and the amount of B added of Pd-B was changed to 3 at%, 5 at%, and 8 at%. 5 nm thick on the surface of the perpendicular magnetization film 20
The medium on which the C protective layer 19 was formed was produced.

When the structure of the perpendicular magnetization film 20 was measured by X-ray diffraction, diffraction peaks of <111> -oriented Pd and Co were detected. The structure of the perpendicular magnetization film 20 is represented by X
<111> -oriented Pd as measured by X-ray diffraction
And Co diffraction peaks were detected. As a result of measuring the magnetic characteristics of the medium in the direction perpendicular to the film surface using a Kerr effect magnetometer, the coercive force was in the range of 4.2 to 3.9 kOe, the nucleation field Hn was in the range of -1.25 to -1.1 kOe, and the angle was The mold ratio SQ was in the range of 1 to 0.98.

FIG. 5A shows a Co / Pd multilayer film and a Co-Pd multilayer film.
The relationship between the lamination ratio of the perpendicular magnetization film and the noise, in which the lamination ratio of the Xa / Pd multilayer film (Xa is V) is changed, is shown with the addition amount of V as a parameter. The horizontal axis in FIG. 5A is (Co-V / Pd multilayer film number) / ｛(Co / Pd multilayer film number) + (Co).
−V / Pd multilayer film number)｝. FIG.
o / Pd multilayer film and Co / Pd-Ya multilayer film (Ya is B)
The relationship between the lamination ratio of the perpendicular magnetization film and the noise, in which the lamination ratio is changed, is shown using the addition amount of B as a parameter. The horizontal axis in FIG. 5B is (Co / Pd-B multilayer film number) / ｛(Co / Pd
(Number of layers of multilayer film) + (number of layers of Co / Pd-B multilayer film)}. In FIG. 5, the noise is a linear recording density of 400 kFC.
The medium noise at I is represented by a value normalized by the signal intensity at a linear recording density of 10 kFCI.

As is clear from FIG. 5, a perpendicular magnetization film in which a Co / Pd multilayer film and a Co-Xa / Pd multilayer film (Xa is V) is laminated, or a Co / Pd multilayer film and a Co / Pd-Ya multilayer film ( Ya is a layer of perpendicular magnetization formed by laminating B) by appropriately selecting the lamination ratio and the amount of addition to form a Co / Pd multilayer film or a Co / Pd multilayer film.
-Xa / Pd multilayer film (Xa is V) or Co / Pd-
It can be seen that noise can be reduced as compared with a perpendicular magnetization film composed of a single combination such as a Ya multilayer film (Ya is B).

FIG. 6 shows the Co / Pd multilayer film of the present invention and Co / Pd multilayer film.
-Xa / Pd multilayer film (Xa is V), total thickness 20
nm perpendicular magnetization film, Co / Pd multilayer film and Co / Pd
The change over time of the residual magnetization of a magnetic recording medium using a perpendicular magnetization film having a total film thickness of 20 nm in which a multilayered Ya film (Y is B) is shown. The addition amount of V and B is 8 at%, and the lamination ratio is 0.4.
An example using the medium described above. Total thickness 20nm for comparison
Perpendicular magnetic recording medium using a Co / Pd multilayer film, a perpendicular magnetic recording medium using a Co-V / Pd multilayer film having a total thickness of 20 nm, and Co-22 at% Cr-1 having a total thickness of 20 nm
A perpendicular magnetic recording medium using 4 at% Pt is also shown. Co /
The magnetic recording medium of the present invention using a perpendicular magnetic film in which a Pd multilayer film and a Co-V / Pd multilayer film are stacked, and a perpendicular magnetic film in which a Co / Pd multilayer film and a Co / Pd-B multilayer film are stacked. The remanent magnetization of the magnetic recording medium of the present invention shows almost the same change with time, and FIG. 6 shows both of them collectively plotted by white circles.

FIG. 6 shows a measurement result in a remanent magnetization state in which the magnetization is greatly attenuated by the demagnetizing field in the perpendicular magnetic recording medium. The vertical axis of the figure indicates the initial remanence Mr (0) after elapse of t time. Ratio of residual magnetization Mr (t) Mr (t) /
Shows Mr (0). Co-22at% Cr-14at%
Since the perpendicular magnetic recording medium using Pt has a nucleation field Hn = 0.5 kOe and a squareness ratio of 0.94, the attenuation of the magnetization in the remanent magnetization state is large. CoV /
A perpendicular magnetic recording medium using a Pd multilayer film has a nucleation field Hn = -0.3 kOe and a squareness ratio of 0.9.
8 is a medium having relatively good perpendicular magnetic anisotropy, but the magnetization was attenuated within a long time. A perpendicular magnetic recording medium using a Co / Pd multilayer film is a medium having a nucleation field Hn = -1.7 kOe and a squareness ratio of almost 1, and hardly any attenuation of magnetization in a remanent magnetization state is recognized.
However, this medium has a drawback that the medium noise is large as shown in FIG. On the other hand, both media of the present invention have excellent perpendicular magnetic anisotropy and nucleation field Hn = -1.
The medium is 2 kOe and has a squareness ratio of almost 1, and hardly any attenuation of magnetization in the residual magnetization state is recognized. Further, as shown in FIG. 5, a feature that the medium noise is small is recognized.

[Embodiment 4] An embodiment in which the relationship between the location of the antiferromagnetic layer for fixing the magnetic domain of the backing soft magnetic layer disposed on the back surface of the perpendicular magnetization film and the spike noise is described with reference to FIG. The washed glass substrate 11 is placed in a high vacuum DC magnetron sputtering apparatus, and a Ta precoat layer 41 having a thickness of 5 nm and a 48 at% Mn-Ir film having a thickness of 20 nm are provided.
Anti-ferromagnetic film 42 and amorphous Co-10 at% T
A soft magnetic film A43 made of a-2 at% Zr was sequentially formed. The thickness of the soft magnetic film A is 10 nm, 50 nm, and 100 n.
m, 200 nm, and 300 nm. 300
C. and heat treatment in a magnetic field of 1 kOe. A solenoid-type electromagnet was disposed behind the substrate, and a current was applied to the solenoid to generate a magnetic field in the radial direction of the disk. As the substrate temperature decreased, the applied magnetic field intensity decreased. This processing provided anisotropy in the radial direction of the magnetic disk. Subsequently, a nonmagnetic intermediate layer 44 made of Pt having a thickness of 5 nm, a perpendicular magnetization film 45 having a multilayer structure having a total thickness of 20 nm, and a C protective layer 46 are successively formed thereon in the same vacuum, and a layer shown in FIG. The medium M (−1,
−2, −3, −4, −5).

In this embodiment, the perpendicular magnetization film 45 having a multilayer structure is used.
Co / Pt multilayer film and Co-Xa / Pt multilayer film (X
a is a perpendicular magnetization film having a total thickness of 20 nm in which V) is laminated, and the added amount of V is 8 at%, and the Co / Pt multilayer film and the Co-Xa / P
An example using a medium with a lamination ratio of the t multilayer film of 0.4 will be described.

The cleaned glass substrate 11 was placed in a high vacuum DC magnetron sputtering apparatus, and a 5 nm-thick T
a Pre-coat layer 41 is formed, and a soft magnetic layer B
47 is Fe-8 at% Ta-12 having a thickness of 300 nm.
An at% C film was formed and heated to 400 ° C. By this heat treatment, a soft magnetic film having a structure in which fine crystal grains of Fe were precipitated was formed. As the backing soft magnetic layer B47, Co-Zr-
Xb (Xb: Ta, Nb, Mo, W, Ni) based amorphous alloy film, Fe-Al-Si alloy or Fe-C-Yc
(Yc: Ta, Hf, Zr, Nb) alloy or the like can be used. 48 atm of 10 nm thickness on the backing soft magnetic layer B47
% Mn-Ir antiferromagnetic film 42 and a film thickness of 10 nm, 50
A soft underlayer A43 made of Co-10 at% Ta-2 at% Zr having an amorphous structure of nm, 100 nm, 200 nm, and 300 nm was formed. Heat treatment was performed at 300 ° C. in a magnetic field of 1 kOe. A solenoid-type electromagnet was disposed behind the substrate, and a current was applied to the solenoid to generate a magnetic field in the radial direction of the disk. As the substrate temperature decreased, the applied magnetic field intensity decreased. This processing provided anisotropy in the radial direction of the magnetic disk. Then, in the same vacuum, a 5 nm thick P
7A, a non-magnetic intermediate layer 44, a perpendicular magnetization film 45 having a multilayer structure with a total film thickness of 20 nm, and a C protective layer 46 are sequentially formed, and a medium N (-1, -2, -3) having the configuration of FIG. , -4,-
5) was produced.

In this embodiment, the perpendicular magnetization film 45 having a multilayer structure is used.
As a Co / Pt multilayer film and a Co / Pt-Ya multilayer film (Y
For a, a perpendicular magnetization film having a total film thickness of 20 nm laminated with B) was used. The amount of B added is 8 at%, and the Co / Pt multilayer film and Co / Pt
An example using a medium in which the stacking ratio of the Pt-Ya multilayer film is 0.4 will be described.

The medium M (-1, -2,
−3, −4, −5) and medium N (−1, −2, −3,
−4, −5) are installed in the magnetic recording apparatus described with reference to FIG. 2, and a spike-like noise signal generated from a magnetic domain formed in the backing soft magnetic layer A43 is measured and compared with an overwrite characteristic when magnetic recording is performed. Table 3 shows the results. Here, the spike-like noise signal is defined as follows. The perpendicular magnetic film 45 is DC-erased by a magnetic head, and an irregular signal having a signal strength of 1.2 times or more of an average DC erasing noise level detected by the reproducing head is set as a spike noise signal, The numbers detected per round were compared. Regarding the overwrite characteristics, a signal having a linear recording density of 300 kFCI was recorded first, and a signal having a linear recording density of 40 kFCI was overwritten on the same recording track. At this time, a characteristic in which the ratio (N / S) of the remaining erased signal (N) recorded first and a signal (S) recorded later was worse than -35 dB was indicated by x, and excellent characteristics were indicated by ○.

[0079]

[Table 3]

As is clear from the comparison in Table 3, by arranging the antiferromagnetic film 42 below the perpendicular magnetization film, the formation of magnetic domains in the backing soft magnetic layer A disposed therebetween can be suppressed. In particular, the anti-ferromagnetic film 42 is disposed at a distance of 200 nm or less from the perpendicular magnetic film 45, and a soft magnetic layer is disposed between the perpendicular magnetic film 45 and the anti-ferromagnetic film 42. Great effect of reduction. Under the antiferromagnetic film 42, a soft magnetic underlayer B47 is also provided.
Is arranged, the recording efficiency can be improved in addition to the reduction of spike noise, and as a result, the overwrite characteristics can be improved.

Although the present embodiment has been described using an example of a material such as a soft magnetic underlayer, an antiferromagnetic layer, a non-magnetic intermediate layer, and a magnetic film, the same effect can be obtained by any other combination of the above materials. Can be obtained.

In this embodiment, as the soft magnetic under layer, Co-
10 at% Ta-2 at% Zr amorphous film, Fe-8 at
% Ta-12 at% C polycrystalline film and Fe-12 at%
As described in the example using the Al-5 at% Si polycrystalline film,
In addition, Co-Zr-Xb (Xb: Ta, Nb, Mo,
W, Ni) amorphous alloy film, or Fe-Al-Si
Alloy or Fe-C-Yc (Yc: Ta, Hf, Zr, N
b) A similar effect can be obtained by using a non-columnar polycrystalline film such as an alloy. Further, Mn-Pt is used as an antiferromagnetic layer.
Although the description has been given of the example using the alloy, the Mn-Fe alloy, M
An n-Ir alloy, a Cr-Mn-Pt alloy, or the like may be used. Further, as the perpendicular magnetization film of the present invention, a perpendicular magnetization film in which a Co / Pt multilayer film and a Co-Xa / Pt multilayer film (Xa is V) are laminated, a Co / Pt multilayer film, and a Co / Pt-Ya multilayer film (Y
In the description of the invention, the content of the invention has been described with a medium configuration including a perpendicular magnetic film in which B) is stacked.
t, or Pd) Multilayer film and Co-Xa / (Pt, or Pd)
A multilayer structure of a multilayer film (Xa: Cr, B, Ta, Mn, V), or a Co / (Pt, or Pd) multilayer film and Co /
(Pt-Ya, or Pd-Ya) Multilayer (Ya: B, T)
a, Ru, Re, Ir, Mn, Mg, Zr, Nb). Further, although an example using a glass substrate as the substrate 11 has been described, a Si disk substrate, a NiP-coated aluminum substrate, a carbon substrate, a polymer substrate, or the like may be used instead of the glass substrate.

[Embodiment 5] An embodiment of a magnetic storage device according to the present invention will be described with reference to FIG. The magnetic storage device
It comprises a magnetic disk 31, a recording / reproducing magnetic head 32, a suspension 33 supporting the magnetic head, an actuator 34, a voice coil motor 35, a recording / reproducing circuit 36, a positioning circuit 37, an interface control circuit 38 and the like. The magnetic disk 31 is made of the perpendicular magnetic recording medium described in the above embodiment, and the protective film is covered with a lubricating film. The magnetic head 32 is composed of a slider, a magnetic recording head provided thereon, and a reproducing head composed of a magnetoresistive, giant magnetoresistive or spin-valve element or a magnetic tunnel element for reproducing signals. You. The gap length of the magnetic head for reproducing the recording signal is set to 0.25 μm or less, preferably 0.08 to 0.15 μm in order to obtain a high-resolution reproduction signal. As a magnetic recording head, either a single pole type head or a ring type head may be used. The track width of the reproducing head is made narrower than the track width of the recording head magnetic pole to reduce reproduction noise generated from both ends of the recording track. The magnetic head 32 is supported by the suspension 33.

Using this apparatus, the evaluation of the medium noise characteristics and the recording / reproducing characteristics of this embodiment were performed. As shown in Tables 1 and 2, the perpendicular magnetic recording medium of the present invention has a recording resolution of 30.
High-density recording of 0 kFCI or more can be realized, high-density characteristics with a medium noise of 8 μVrms / μVpp and an error rate of 10 ⁻⁶ or less at this density can be obtained, and a surface recording density of 50
A magnetic disk drive of Gb / in ² or more can be configured.

[0085]

According to the present invention, Co / (Pt, or P
d) Multilayer film and Co-Xa / (Pt, or Pd) multilayer film (X
a: a laminated structure of Cr, B, Ta, Mn, V) or a Co / (Pt, or Pd) multilayer film and Co / (Pt-Y)
a, or Pd-Ya) multilayer film (Ya: B, Ta, Ru,
A perpendicular magnetic film having a laminated structure of (Re, Ir, Mn, Mg, Zr, Nb) is used, and an amorphous material or a non-columnar polycrystalline thin film is used as a backing magnetic layer. By controlling the magnetic domain structure, it is possible to suppress irregular magnetic domains on the surface of the perpendicular magnetic film medium that causes medium noise and to reduce the size of the irregular magnetic domains. A perpendicular magnetic recording medium suitable for density magnetic recording can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a basic structure of a perpendicular magnetic recording medium according to the present invention.

FIG. 2 is an explanatory diagram of a magnetic storage device.

FIG. 3 is a schematic sectional view showing one embodiment of a perpendicular magnetic recording medium according to the present invention.

FIG. 4 is an explanatory diagram of the angle dependence of magnetic characteristics.

FIG. 5 is a performance comparison diagram of noise characteristics.

FIG. 6 is a performance comparison diagram of magnetization stability.

FIG. 7 is a schematic sectional view showing one embodiment of a perpendicular magnetic recording medium according to the present invention.

[Explanation of symbols]

11: substrate, 12: soft magnetic underlayer, 13: nonmagnetic intermediate layer, 14: multilayer, 15: multilayer, 16: multilayer, 1
7: multilayer film, 18: multilayer film, 19: protective layer, 20: perpendicular magnetization film, 31: magnetic disk, 32: magnetic head, 3
3: Suspension, 34: Actuator, 35: Voice coil motor, 36: Recording / reproducing circuit, 37: Positioning circuit, 38: Interface control circuit, 41: Precoat layer, 42: Antiferromagnetic film, 43: Soft magnetic film A, 4
4: non-magnetic intermediate layer, 45: perpendicular magnetization film, 46: protective layer,
47: Soft magnetic film B.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 10/26 H01F 10/26 (72) Inventor: Itaru Tanahashi 1-280, Higashi-Koigabo, Kokubunji-shi, Tokyo Hitachi, Ltd. Hitachi, Ltd. At the Central Research Laboratory of the Works (72) Atsushi Kikukawa, Inventor 1-280, Higashi Koigakubo, Kokubunji-shi, Tokyo F-term at the Central Research Laboratory of Hitachi, Ltd.

Claims (5)

[Claims] 1. A perpendicular magnetic recording medium comprising a perpendicular magnetic film including a Co / Pt or Co / Pd multilayer film, wherein a part of the perpendicular magnetic film is Co-Xa / Pt or Co-Xa / P.
A perpendicular magnetic recording medium comprising a d multilayer film layer (Xa is at least one element selected from Cr, B, Ta, Mn, and V). 2. A perpendicular magnetic recording medium comprising a perpendicular magnetic film including a Co / Pt or Co / Pd multilayer film, wherein a part of the perpendicular magnetic film has Co / Pt-Ya or Co / Pd-Y.
a multilayer film layer (Ya is B, Ta, Ru, Re, Ir, M
at least one element selected from n, Mg, Zr, and Nb). 3. The perpendicular magnetic recording medium according to claim 1, further comprising a soft magnetic layer below the perpendicular magnetization film, wherein the soft magnetic layer is formed of Co—Zr—Xb (Xb is Ta, Nb,
At least one element selected from Mo, W, and Ni) -based amorphous alloy films, Fe-Al-Si alloys and Fe-C
Non-columnar polycrystalline films such as -Yc (Yc is at least one element selected from Ta, Hf, Zr, and Nb) alloys;
A perpendicular magnetic recording medium comprising any one of a Ni-Fe alloy. 4. The perpendicular magnetic recording medium according to claim 3, further comprising a non-magnetic intermediate layer between said soft magnetic layer and said perpendicular magnetic film. 5. The perpendicular magnetic recording medium according to claim 3, further comprising an antiferromagnetic layer film of IrMn, PtMn, PtCrMn or the like separated from the back surface of the perpendicular magnetization film by a distance of 10 to 200 nm. Characteristic perpendicular magnetic recording medium.