JPH0773433A - Magnetic recording medium, its production and magnetic recorder - Google Patents

Abstract

PURPOSE:To provide a magnetic recording medium, its producing method, and a magnetic recorder where low floating of a head and high-density recording are possible. CONSTITUTION:With respect to the magnetic recording medium which is provided with at least a nonmagnetic disk substrate 11 and a magnetic film 14 formed on the nonmagnetic disk substrate 11 directly or with a foundation film 13 of at least one layer between them, the value of a product Brdelta between a residual magnetic flux density Br of the magnetic film 14 measured in the head running direction and an overall film thickness delta of the magnetic film is set to 5Gmum to <80Gmum. Further, the value of an anisotropic magnetic field Hk is set to 7kOe to 20kOe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium such as a magnetic drum, a magnetic tape, a magnetic disk and a magnetic card, and a magnetic recording device, and particularly to a thin film medium suitable for high density magnetic recording and a small and large size using the thin film medium. The present invention relates to a capacitive magnetic recording device.

[0002]

2. Description of the Related Art In recent years, as information processing devices such as electronic computers have become smaller and faster, there has been an increasing demand for larger capacity and faster access to magnetic disk devices and other external storage devices. In particular, the magnetic disk recording device is an information storage device suitable for high density and high speed, and its demand is further increasing.

As a recording medium used in a magnetic disk device, a medium in which powder of an oxide magnetic material is coated on a substrate and a thin film medium in which a thin film of a metal magnetic material is sputter-deposited on a substrate have been developed. Among them, the thin film medium is suitable for high-density recording / reproduction because the magnetic substance contained in the magnetic recording layer has a higher density than the coating type medium. Al-Mg alloy, chemically strengthened glass, organic resin, ceramics, etc. are used for the substrate of the thin film medium, and the center line average roughness (hereinafter abbreviated as Ra) is used on the substrate surface for the purpose of preventing head adhesion or improving magnetic characteristics. Groove) or protrusion having a thickness of 2 to 10 nm is formed.

Further, by using a giant magnetoresistive effect type element (hereinafter abbreviated as GMR) in the reproducing portion of the magnetic head, the reproducing sensitivity of the head is improved as compared with the conventional induction type magnetic head. A head (hereinafter abbreviated as GMR head) has been developed. If a GMR head is used, a sufficient signal S / N can be obtained even if the recording bit area is small, so that the recording density of the medium can be dramatically improved.

A Co alloy sputtered film having a high saturation magnetic flux density (Bs) is mainly used for the magnetic film. Co alloy has a hexagonal close packed (hcp) crystal structure, and the easy axis of magnetization is the c-axis of the crystal. Therefore,
In the in-plane recording method, it is necessary to orient and grow the crystal so that the c axis is parallel to the substrate surface. Therefore, Cr having a body centered cubic (bcc) structure,
Alternatively, a technique of using an alloy film of Cr-Ti, Cr-V or the like and epitaxially growing a Co alloy thin film on the alloy film is used.

The magnetic characteristics of the conventional magnetic film are measured in the head traveling direction as described in, for example, the magazine "EEE Transaction on Magnetics" Vol. 29 (1993), p. 307. The product (Brδ) of the measured residual magnetization of the magnetic film (hereinafter abbreviated as Br) and the total film thickness (δ) of the magnetic film is about 80 to 180 Gμm, and the coercive force (Hc) measured in the head traveling direction is 1600. ~ 21
It is about 00 Oe.

Also, the magazine "I-E-E-Transaction on Magnetics" Vol. 29 (19
1993, p. 292, by observing the crystal lattice of the magnetic film with a transmission electron microscope, the crystal grain boundaries, the orientation of the c-axis, the face centered cubic (fc)
c) The results of analysis of the presence of a different phase having a crystal structure, the density of stacking faults, and the like are described.

[0008]

In order to further improve the recording density in the future, development of a GMR head having high reproduction sensitivity,
Also, it is essential to develop a recording medium having magnetic characteristics adapted to a GMR head and having a smoother surface than before in order to reduce the flying height of the head. Conventional recording medium and G
When a recording / reproducing experiment was performed using an MR head, Br
δ was 80 Gμm or more, and when reproduced with a GMR head, noise increased significantly with output, and high S / N could not be obtained. Also, when Brδ is large, GMR
There is a problem that the output of the head is saturated and the reproduced signal waveform becomes asymmetric between the positive side and the negative side, which makes it difficult to discriminate the signals. Further, when the Br δ of the medium is large, the magnetization of the GMR film excessively rotates and becomes unstable, which causes a problem that Barkhausen noise occurs from the head and a recording bit error occurs.

To solve such a problem, Br of the medium is used.
It is effective to reduce δ to less than 80 Gμm. For that purpose, the thickness δ of the magnetic film or the residual magnetic flux density Br
Need to be reduced. However, when Brδ was set to the above value by any method, the coercive force Hc of the medium was significantly lower than that of the conventional medium and was less than 1000 Oe. When Hc decreases in this way, the linear recording density becomes 100.
In a high recording density region of kBPI or higher, the head output is remarkably reduced, which causes a problem that an error occurs.

Further, in the above-mentioned medium according to the prior art, a method of isolating magnetic film crystal grains has been proposed because it is considered that the reduction of the inter-particle interaction of the magnetic film is effective for reducing the medium noise. However, this method has a problem that the output at a high recording density is reduced due to the decrease in the coercive force squareness ratio (S ^* ) and the corrosion resistance of the magnetic film is reduced. Further, in order for the magnetic flux from the medium to be effectively detected by the GMR head, the flying height of the head needs to be 0.1 μm or less. However, in the conventional medium, a texture with Ra of 2 nm or more is formed on the substrate surface for the purpose of preventing head sticking or improving magnetic characteristics. When the flying height is reduced, the protrusions of the texture easily come into contact with the head, and the flying height increases. Is not reduced to 0.1 μm or less. Therefore, it is necessary to form a medium having a smoother surface than in the past so that the head can fly stably.

In view of the above problems and circumstances, the first aspect of the present invention
It is an object of the present invention to provide a recording medium adapted to a GMR head having high reproduction sensitivity and capable of obtaining high S / N. That is, when the flying height of the GMR head is 0.1 μm or less, the linear recording density is 150 kBPI or more and the track density is 10 kTP.
Recording / reproduction at I or higher (1.5 GMb / in in areal recording density)
It is to provide a magnetic recording medium having an S / N value of 1 or more (corresponding to ² or more). A second object of the present invention is to provide a method of manufacturing such a medium with good reproducibility, and a third object of the present invention is to provide a large-capacity and highly reliable magnetic recording apparatus using such a medium. Is to provide.

[0012]

When a GMR head is used, the product (Brδ) of the residual film thickness of the magnetic film and the total film thickness of the magnetic film measured in the running direction of the head as a medium is reduced, and It is important to reduce the influence of the demagnetizing field of the magnetization transition portion by increasing the anisotropic magnetic field (Hk) of the magnetic film.

As a result of intensive studies on the magnetic characteristics of the medium and the recording / reproducing characteristics of the GMR head, the present inventors have found that, in order to achieve the above object, the residual magnetization of the magnetic film of the medium measured in the head traveling direction. The product Brδ of Br and the total magnetic film thickness δ is set to 5 Gm or more and less than 80 Gm and the anisotropic magnetic field Hk of the medium is 7 kOe or more, 2
It has been found that it is effective to set it to 0 kOe or less.
In particular, in order to further reduce the medium noise and improve the S / N at a linear recording density of 150 kBPI or more, the value of Brδ is preferably 5 Gm or more and 30 Gm or less.

The value of Hk can be measured by the method described below using a torque meter. That is, while applying a magnetic field to the substrate surface of the magnetic film sample, the sample is reciprocally rotated 360 degrees on the substrate surface, and the area inside the obtained torque curve is obtained. This area is called a rotation history loss Wr. This Wr is plotted against the reciprocal of the applied magnetic field, and the magnetic field at which Wr becomes 0 on the high magnetic field side is Hk.

In the above magnetic recording medium, the total magnetic film thickness δ
When the coercive force is 5 nm or more and 30 nm or less and the coercive force is 1000 Oe or more and 3500 Oe or less, the disorder of the magnetization in the magnetization transition region is reduced, the width of the magnetization transition region is reduced, and high output can be obtained even in the high recording density region. When the width of the grain boundary of the magnetic film crystal is 0.5 nm or more and 5 nm or less, Hc is improved and noise is reduced.

In the above magnetic recording medium, the magnetic film has a hexagonal crystal structure, the c-axis thereof is substantially oriented in the in-plane direction of the substrate, and the hexagonal lattice constants a and When the ratio of the length of c, c / a, is 1.3 or more and 1.6 or less, the anisotropic magnetic field is improved. Here, the values of c and a are obtained by an X-ray diffraction analysis method, an electron beam diffraction analysis method, or a transmission electron microscope observation method of the magnetic film. In the X-ray diffraction analysis, the incident X-ray may be incident on the sample surface as necessary. It is necessary to tilt with respect to.

In the above magnetic recording medium, if the density of stacking faults forming face-centered cubic lattice (fcc) in the magnetic film crystal having a hexagonal crystal structure is set to 5% or less, the anisotropic magnetic field is improved. The width of the crystal grain boundary of the magnetic film or the density of stacking faults can be obtained by directly observing and averaging the lattice images of about 100 magnetic film crystal grains with a high resolution transmission electron microscope.

In the above magnetic recording medium, when the total concentration of oxygen, carbon and nitrogen in the magnetic film is 1 atomic% or less, the anisotropic magnetic field is further improved. Here, the total concentration of oxygen, carbon, and nitrogen in the magnetic film can be obtained by a fluorescent X-ray analysis method or a secondary ion mass spectrometry method using cluster ions of Cs ions and analysis elements. In manufacturing the magnetic recording medium described in this specification, the evacuation rate of the film forming vacuum chamber and the film growth rate are increased, and a negative bias voltage of 10 V or more is applied to the substrate during formation of the nonmagnetic underlayer film and the magnetic film. Fifty
When 0 V or less is applied, the crystallinity of the film is improved and the anisotropic magnetic field is improved. The same effect can be obtained even if an AC bias contains a DC component.

By applying the above bias voltage, the ion implantation method, etc., Ar, Xe,
When at least one element of Kr is made to exist at an atomic concentration of 0.1% or more and 5% or less, compressive stress increases in the film surface and the anisotropic magnetic field and coercive force improve. In particular, when Xe or Kr having a large atomic radius is mixed, the compressive stress in the film surface can be significantly improved, and the anisotropic magnetic field and the coercive force can be improved.

In the above magnetic recording medium, the magnetic film contains Co as a main component, and Ni, Cr, Mo,
High Hc is obtained by adding at least one element selected from the group consisting of W, Zr, Ta, Nb, Al, Si, Pt, B, and P. In particular, when the magnetic film has Co as a main component and Cr is added to the magnetic film at a concentration of 15 atom% or more and 22 atom% or less, noise of the medium is significantly reduced.

The substrate temperature during film formation is 200 ° C. or higher, 5
When the temperature is 00 ° C. or less, the segregation structure in the magnetic film is promoted and Hc is improved. When the medium is heat-treated at a temperature of 200 ° C. or higher after film formation, segregation is promoted, coercive force is increased, and noise is reduced. However, if the heat treatment temperature is higher than 600 ° C., the grain size becomes large and noise increases, so it is desirable to perform the heat treatment at 600 ° C. or lower.

Cr, Mo, W, V, Ta, Nb, Zr,
When the magnetic film is multi-layered into two or more layers by a non-magnetic intermediate layer having a film thickness of 0.5 nm or more and 5 nm or less containing at least one of Ti, B, Be, C, Ni-P, and Ni-B as a main component. Media noise is significantly reduced. When the center line average roughness Ra measured in the direction perpendicular to the head running direction on the surface of the magnetic film is 0.3 nm or more and 1.9 nm or less, stable flying can be achieved even if the head flying height is 0.1 μm or less. Further, when the magnetic recording medium has a protective film on the magnetic film and the center line average roughness Ra measured in the direction perpendicular to the head running direction on the surface of the protective film is 0.3 nm or more and 3 nm or less, the head flying height increases. Even if the amount is 0.1 μm or less, it is possible to stably float.

C is provided between the non-magnetic disk substrate and the magnetic film.
r, Mo, W, Nb, or Ta as the main component,
An alloy underlayer film containing at least one element selected from Ti, Pt, Pd, Si, Fe, V, Ru, P, and B is formed adjacent to the magnetic film, and the film thickness is 5 nm or more and 500.
When the thickness is less than or equal to nm, the orientation of the magnetic layer is improved, the anisotropic magnetic field is improved, and the medium noise is reduced. Further, the underlayer is composed of at least two nonmagnetic layers, and the substrate-side underlayer is Zr, Si, Ti, Sc, Al, C, Ge, S.
b, Ga, Ru, Pd, V, Nb, Ta, Hf, Rh,
Ni-P, Ni-B, or alloys containing these as the main components, chemically strengthened glass, organic resin, Ti, S
Even when a substrate made of i, carbon, or a ceramic material such as TiO ₂ or SiC is used, the anisotropic magnetic field is improved and high Br and coercive force are obtained.

For the magnetic layer, Co, Fe, Ni or an alloy containing these as the main components is desirable.
Ni, Co-Cr, Co-Fe, Co-Mo, Co-
It is preferable to use an alloy such as W or Co-Re as a main component, and to orient the crystal so that the (110) crystal lattice plane of the hexagonal crystal structure is substantially parallel to the substrate because Hc is improved.
In addition, when excellent corrosion resistance is required, Co-Ni-Zr, Co-Cr-Ta, C is used as a magnetic material forming the magnetic film.
It is desirable to use an alloy containing o-Ni-Cr and Co-Cr-Pt as main components.

Carbon as a protective layer for the magnetic film, hydrogenation
Carbon or non-magnetic with carbon as the main component
Form a material with a film thickness of 10 to 50 nm and
A lubrication layer such as fluoroalkyl polyether has a thickness of 3 to 2
High reliability by setting 0 nm and high density recording possible
An effective magnetic recording medium can be obtained. WC, (W-
Mo) -C and other carbides, (Zr-Nb) -N, Si₃N
_FourNitride such as SiO₂ , ZrO₂Oxides, etc.
Is B, B_FourC, MoS₂, Rh, etc.
It is preferable because the corrosion resistance can be improved. These protective films are
1 to 20% in area ratio by etching the surface using a disc
Projections or adjust film formation conditions, composition, etc.
The protective film allows the protective film to be
It is more preferable to have a large surface roughness.

When the Ra on the surface of the medium is set to a value smaller than the conventional value, in order to suppress the adhesion of the head during CSS operation, plasma protection is performed using a fine mask after forming a protective film on the magnetic film. 20nm height on the surface
When the following fine irregularities are formed, or when fine protrusions are formed on the surface of the protective film by using a target of a compound or mixture, or when fine irregularities are formed on the surface by heat treatment, the head and The frictional force of the medium can be reduced, and the problem of the head sticking to the medium is avoided.

By combining this magnetic recording medium with a GMR head having a track width of 2 μm or less, it is possible to provide a magnetic recording device having a large capacity and high reliability. Further, by combining with a signal processing circuit based on the maximum likelihood decoding method, the recording density can be further improved.

[0028]

If the product Brδ of the residual magnetization Br of the medium and the film thickness δ is excessively large, the magnetization rotation of the GMR film becomes unstable, and Barkhausen noise is generated from the head. Further, as Brδ increases, the diamagnetic field Hd increases in the transition region of the recording bit and the fluctuation of the magnetization increases, so that the GM having high reproduction sensitivity.
When the R head is used, the medium noise Nd becomes extremely large. Further, since the GMR head has high reproduction sensitivity, Brδ
Is 80 Gμm or more, the reproduction output is saturated and the waveform of the output signal becomes asymmetric. On the other hand, when Br δ is less than 5 Gμm, the reproduction output is small and the magnitude of the medium noise is about the same, so that a high signal S / N cannot be obtained. Therefore, the GM to use
Brδ of the medium is 5 Gμm in conformity with the reproducing sensitivity of the R head.
As described above, high S / is achieved by controlling in the range of less than 80 Gμm.
N can be obtained.

By controlling Brδ in the range of 5 Gμm or more and 30 Gμm or less, the fluctuation of the magnetization in the recording bit can be reduced, and the medium noise can be remarkably reduced at the high linear recording density of 150 kBPI or more. Further, at a high linear recording density of 150 kBPI or more, the length of the recording bit becomes short, and the zigzag shape of the magnetization transition portion becomes approximately the same as the bit length. Further, the interaction between the magnetization transition portions also appears, and the shape of the recording bit is not an ideal rectangular shape as in the conventional low recording density, but tends to be an irregular shape. Even in such a case, in order to obtain a high output, it is effective to increase the value of the anisotropic magnetic field Hk of the magnetic film of the medium to 7 kOe or more and 20 kOe, which is higher than the conventional value, and reduce the influence of the demagnetizing field of the magnetization transition portion. Is.

Further, in order to set Hc to 1000 Oe or more, it is necessary to set δ to a value of 5 nm or more and 30 nm or less. When Hc is 1000 Oe or more, the width of the magnetization transition region is reduced and the output half recording density D ₅₀ is improved, so that a high output can be obtained even at a high linear recording density, and at the same time, the medium noise N
Since d is reduced, the S / N ratio of the reproduced signal is improved. Also,
When Hc is higher than 3500 Oe, the overwrite characteristic becomes 20 dB or less, so it is preferable to set Hc to 3500 Oe or less. When the total magnetic film thickness δ of the medium is 5 nm or less, the crystal grain size of the magnetic film becomes smaller as δ decreases, and the coercive force Hc is reduced due to the effect of temperature fluctuation of magnetization.
Will fall. When the magnetic film thickness δ is 30 nm or more, the magnetic film is likely to be magnetized in the perpendicular direction and Hc is lowered, which is not preferable.

The width of the grain boundary of the magnetic film crystal is 0.5 nm or more,
When the thickness is 5 nm or less, magnetic interaction between magnetic clusters is reduced, Hc is improved, and medium noise is reduced. The c-axis of the magnetic film having a hexagonal crystal structure is oriented substantially in the in-plane direction of the substrate, and compressive strain in the in-plane direction of the magnetic film is imparted to the hexagonal lattice constant a and When the value of the ratio c / a of the lengths of c is 1.3 or more and 1.6 or less, Hk and Hc can be improved by the inverse magnetostrictive effect as compared with the conventional case.

When the density of stacking faults forming the face-centered cubic lattice in the magnetic film crystal is reduced to 5% or less, a hexagonal crystal having a large magnetic anisotropy constant is converted into a magnetic domain wall having a width of 20 to 30 n.
Since H can be controlled to a uniform size, Hk and Hc are improved. When the total concentration of oxygen, carbon, and nitrogen in the magnetic film is 1 atomic% or less, disorder and defects of the hexagonal crystal lattice of the magnetic film are reduced, so that the magnetic anisotropy constant is increased and Hk and Hc are improved. .

In order to form such a high Hk and high Hc magnetic film, at the time of forming the non-magnetic underlayer film and the magnetic film, the evacuation speed of the film forming chamber is increased to reduce the concentration of impurity gas such as water vapor. It is effective to increase the film speed and apply a substantially negative bias voltage of 10 V or more and 500 V or less to the substrate. In particular, it is possible to form a magnetic film having desired magnetic characteristics by applying a voltage of -200V or more. This is because the concentration of the impurity gas in the deposition chamber is reduced, the deposition rate is increased, and the bias voltage is applied to remove the contaminated layer on the surface of the substrate and the underlying film, the removal of impurities such as oxygen and nitrogen, and the substrate surface of vapor deposition particles. This is because defects and disorder of the crystal lattice are reduced by promoting diffusion, and crystal grain boundaries are developed due to segregation of nonmagnetic elements to the crystal grain boundaries.

Further, in order to form a high Hk and high Hc magnetic film, the size of the crystal lattice of the underlayer film should be matched with the size of the crystal lattice of the magnetic film to reduce defects and disorder of the crystal lattice. is important. To this end, Cr, Mo, W, N
b or Ta is the main component of the underlying layer, Ti,
It is effective to add at least one element selected from Pt, Pd, Si, Fe, V, Ru, P, and B. Further, like the magnetic film, it is important to reduce defects and disorder of the crystal lattice of the underlayer. For that purpose, the underlayer is composed of at least two non-magnetic layers, and the substrate-side underlayer is made of Z.
r, Si, Ti, Sc, Al, C, Ge, Sb, Ga,
Ru, Pd, V, Nb, Ta, Hf, Rh, Ni-P,
By using Ni-B or an alloy containing these as the main components, the disorder of the crystal orientation due to the substrate material and the diffusion of impurities can be suppressed.

In order to effectively detect the magnetic flux from the medium with the GMR head, it is effective to reduce the flying height of the head. Here, the center line average roughness Ra of the surface of the medium protective film measured in the direction perpendicular to the head traveling direction is 0.3.
When the thickness is not less than 3 nm and not more than 3 nm, the head flies stably even if the flying height is not more than 0.1 μm. Further, the center line average roughness R measured on the surface of the magnetic film in a direction perpendicular to the head traveling direction.
When a is 0.3 nm or more and 1.9 nm or less, the head flies stably even when the flying height is 0.1 μm or less.

After forming a protective film on the magnetic film, plasma etching is performed using a fine mask to increase the height of the surface to 2
When fine irregularities of 0 nm or less are formed, fine projections are formed on the surface of the protective film by using a target of a compound or mixture, or fine irregularities are formed on the surface by heat treatment, the contact area between the head and the medium, Since the frictional force is reduced and the problem of the head sticking to the medium is avoided, it is particularly preferable to make the protective film have a surface roughness different from that of the magnetic film surface by the above-mentioned treatment or the like. Since the medium according to the present invention has an extremely high S / N, the track width is 2 μm.
Track density of 1 when reproduced with the following GMR head
A high-capacity magnetic recording device having an S / N of 1 or more can be obtained at a high recording density of 0 kTPI or more and 150 kBPI or more.

[0037]

EXAMPLES The present invention will be described in more detail below with reference to examples.
Reveal FIG. 1 shows a cross-sectional structure of a thin film medium according to the present invention.
It is shown as a formula. In the figure, reference numeral 11 is A
1-Mg alloy, chemically strengthened glass, organic resin, Ti, S
i, carbon, or TiO₂, SiC, etc.
Substrate 12 and 12 'are both sides of the substrate 11.
Non-magnetic film made of Ni-P, Ni-WP, etc.
It is a layer. When using Al-Mg alloy as the substrate
Used a substrate with such a plating layer as the substrate
However, for other substrates, 12 and
12 'may be omitted. 13 and 13 'are Cr, Mo,
W, V, Ta, Nb, Zr, Ti, B, Be, C, Ni
-P, Ni-B made of an alloy containing as a main component
Metal base film, 14 and 14 'are formed on the base film
Co-Ni, Co-Cr, Co-Fe, Co-M
o, Co-W, Co-Pt, Co-Re, Co-P, C
o-Ni-Pt, Co-Cr-Ta, Co-Cr-P
t, Co-Ni-Cr, Co-Cr-Al, Co-Cr
-Nb, Co-Ni-P, Co-Cr-Si, etc.
And 15 and 15 'are formed on the magnetic film.
Formed on carbon, WC, (W-Mo) -C, (W-
Zr) -C, SiC, (Zr-Nb) -N, Si
₃N_Four, SiO₂, ZrO₂, Boron, B_FourC, Mo
S ₂, Or a non-magnetic protective film made of Rh, etc., respectively.
Show.

[Example 1] Outer diameter 95 mm, inner diameter 25 m
Ni-12P (wt%) on both sides of a disk substrate made of Al-4Mg with a thickness of 0.8 mm (the number preceding the atomic symbol indicates the content of the material. The unit of the content is wt%). 13 μm in thickness was formed on the plated layer of (1). The surface of this non-magnetic substrate was smooth-polished using a lapping machine until the centerline average roughness Ra became 0.3 nm, washed and dried. Then, using a tape polishing machine, in the presence of an abrasive having an average abrasive grain size of 0.5 μm or less,
Disk substrate 1 with polishing tape through contact roll
By pressing 1 on both sides of the disk surface while rotating, texture grooves having irregular depth and density in the head running direction were formed on the substrate surface. Further, dirt such as abrasives attached to the substrate was washed and dried. The center line average roughness Ra of the groove on the substrate surface measured in the radial direction is 0.7 nm,
The average density of the grooves having a depth of 1 nm or more and 50 nm or less was 20 at a distance of 1 μm in the direction substantially perpendicular to the head traveling direction.

The disk substrate 24 is placed in a sputtering apparatus and the exhaust rate of water vapor per volume of the vacuum chamber is 200 l /
Using an exhaust pump of s or more, the degree of vacuum is maintained at 2 nTorr, the substrate is heated to 250 ° C., and then 0.5 mTorr.
A Cr underlayer 23 having a film thickness of 50 nm was formed under the conditions of argon pressure. Co-17Cr-5T is formed on this base film.
An a (atomic%) alloy magnetic film 22 was formed to a thickness of 5 to 30 nm. After that, a hydrogen-containing carbon protective film 21 having a film thickness of 20 nm was formed on the magnetic film. Further, a particle-forming mask having an opening pitch of 1 μm or more and 100 μm or less was provided on the surface of the protective film. After that, the portion of the protective film not covered by the mask is etched by oxygen plasma to a depth of 1 nm or more,
The protective film has a surface roughness different from that of the surface of the magnetic film by etching to a thickness of not more than nm.

As a result, as shown in FIG. 2, unevenness 2 having a pitch of 1 μm or more and 100 μm or less on the surface of the carbon protective film.
5 was formed. A lubricating layer such as an adsorbent perfluoroalkylpolyether was formed on the protective film. The magnetostatic characteristics (Hc, Br, Hk) of the medium are the maximum applied magnetic field of 14 kO.
The measurement was performed using a vibration type magnetometer (e.g., e.g., e.g., VSM) and a torque meter. In addition, the recording / reproducing characteristic is set to 0.
06μm, effective gap length 0.4μm, track width 2μ
m, recording / reproducing S at a linear recording density of 150 kBPI using a composite type thin film magnetic head having a GMR element in the reproducing section.
The value of / N was determined.

In the above medium, by controlling the film thickness δ of the magnetic film, the value Brδ of the residual magnetization Br and δ of the medium magnetic film measured in the head traveling direction is set to 5 Gμm or more,
Hg is controlled to 79 Gμm or less, and further, by controlling the evacuation speed of the film forming chamber, the film forming speed of the underlying film and the magnetic film, and the DC bias voltage on the substrate side during film formation in the range of −10 V to −500 V. A medium in which the pressure was changed from 5 kOe to 30 kOe was prepared.

FIG. 3 shows the relationship between Hk and S / N during recording and reproduction. S in the range where Hk is 7 kOe or more and 20 kOe or less
It was confirmed that / N could be 1 or more. At this time, the coercive force Hc measured in the head traveling direction is 1000 Oe or more,
It was 3500 Oe or less. As a result of X-ray diffraction analysis of the magnetic recording medium formed by the above method, it was found that in the Cr underlayer, crystals were oriented and grown so that the (200) crystal lattice plane of the body-centered cubic structure was substantially parallel to the substrate surface. confirmed.
Further, in the magnetic layer, the (110) plane of the hexagonal structure was oriented substantially parallel to the disk substrate surface, and the c-axis was oriented substantially parallel to the disk substrate surface. Also, oxygen in the magnetic film,
It was confirmed that the total concentration of carbon and nitrogen was 1 atomic% or less.

Further, the center line average roughness Ra measured in the radial direction of the protective film surface is 0.3 nm or more and 3 by controlling the abrasive grain size and the processing time during the texture formation of the substrate.
The center line average roughness Ra of the magnetic film surface is 0.3 nm or less.
As a result of seeking 100,000 times from the inner circumference to the outer circumference of the MR head at a flying height of 0.06 μm using a medium having a thickness of not less than 1.9 nm and not more than 1.9 nm, it was confirmed that the head did not come into contact with the medium.

The above effect is obtained by applying Co-10Ni- to the magnetic material.
The same was found when 10Cr (atomic%), Co-40Ni-5Zr (atomic%), and Co-30Ni-10Pt (atomic%) were used. Further, when the magnetic film is directly formed on the substrate without forming the base film, the coercive force is reduced by 100 to 200 Oe as compared with the case where the base film is formed, but the S / N is 1 or more. Was confirmed. Further, the magnetic film is formed of Cr, Mo, W, V, Ta, Nb, Zr, T.
When a non-magnetic intermediate layer composed of i, B, Be, C, Ni-P, and Ni-B and having a film thickness of 0.5 nm or more and 5 nm or less is formed into two layers, the medium noise is a single layer. It was reduced to about 2/3 that of the magnetic film, and the S / N value was further improved.

[Embodiment 2] Outer diameter 65 mm, inner diameter 20 m
The center line average roughness Ra of the n-sided canasite glass substrate having a thickness of 0.3 mm and a thickness of 0.3 mm was 0.3 n using a lapping machine.
It was smoothly polished until it reached m, washed and dried. This disk substrate was held in vacuum in a sputtering device using an exhaust pump having an exhaust rate of water vapor per volume of a vacuum chamber of 400 l / s or more, and after heating the substrate temperature to 400 ° C.,
Under the conditions of an argon pressure of 5 mTorr, Ti was formed to a thickness of 20 nm as the first underlayer film, and then a Cr-15Ti (atomic%) alloy was formed to a thickness of 50 nm as the second underlayer film. A 10 nm thick Co-Cr- film is formed on the composite underlayer.
A Pt-Si magnetic film was formed. At that time, 13.
A high frequency bias voltage of 56 MHz was applied at 300 W.
At this time, the DC component of the bias voltage is -300 V, Br?
The value of was 25 Gμm.

By controlling the additive concentration of Cr, Pt, and Si in the magnetic film in the range of 5 atom% or more and 20 atom% or less, the grain boundary width of the magnetic film crystal observed by a high resolution transmission electron microscope. Was controlled in the range of 0.1 nm or more and 10 nm or less. The value of Brδ at this time is 5 Gμm or more, 3
The value of Hk was 0 Gμm or less, and the value of Hk was 7 kOe or more and 20 kOe or less.

FIG. 4 shows the width of the grain boundary of the magnetic film crystal and the coercive force H.
c, head flying height 0.03 μm, linear recording density 200
The relationship between the recording / reproducing S / N values in kPBI is shown. Hc is 1 when the width of the grain boundary is 0.5 nm or more and 5 nm or less
000 Oe or more, 3500 Oe or less, and S / N of 1 or more, showing good characteristics. As a result of X-ray diffraction analysis of the magnetic recording medium formed by the method of this example, crystals were oriented and grown in the Cr underlayer so that the (110) crystal lattice plane of the body-centered cubic structure was substantially parallel to the substrate surface. Was confirmed. Moreover, in the magnetic layer, the (100) plane of the hexagonal structure was oriented so as to be substantially parallel to the surface of the disk substrate. The center line average roughness Ra of the protective film surface was 1.0 nm, and the center line average roughness Ra of the magnetic film surface was 0.9 nm.

Using the medium of this example, the flying height is 0.03.
At the μm, the GMR head is 10
As a result of 10,000 seeks, it was confirmed that contact between the head and the medium did not occur. This effect is achieved by using Zr as the first underlayer film,
Si, Sc, Al, C, Ge, Sb, Ga, Ru, P
d, V, Nb, Ta, Hf, Rh, Ni-P, Ni-B
Alternatively, it was similarly observed when an alloy containing these as the main components was used.

[Embodiment 3] Outer diameter 48 mm, inner diameter 12 m
The surface of the carbon substrate having a thickness of 0.3 mm and a thickness of 0.3 mm was smoothly polished using a lapping machine until the center line average roughness Ra was 0.3 nm, washed and dried. After that, using a tape polishing machine, in the presence of a diamond abrasive having an average abrasive grain size of 1 μm or less, the polishing tape is pressed against both sides of the disk surface while rotating the disk substrate through a contact roll, so that the depth and density of the substrate surface are increased. Formed irregular texture grooves. Further, dirt such as abrasives attached to the substrate was washed and dried.

The center line average roughness Ra of the grooves on the substrate surface measured in the radial direction is 0.5 nm, and the average density of the grooves having a depth of 1 nm or more and 50 nm or less at a distance of 1 μm in the direction substantially perpendicular to the head running direction is 50. It was a book. This disk substrate was held in a vacuum in a sputtering apparatus by using an exhaust pump having an evacuation rate of water vapor per vacuum chamber volume of 500 l / s or more, and the substrate temperature was heated to 400 ° C., and then 1 mTorr.
A Cr-15Ti base film was formed to a thickness of 10 nm under the condition of an argon pressure of r. Co-film with a thickness of 5 nm is formed on this base film.
A Cr-Pt-Ta magnetic film was formed. At this time, the value of Brδ was 10 Gμm.

The DC bias voltage during film formation is from −10V to −
By controlling in the range of 500 V, the ratio of the lattice constants a and c of the magnetic film having the hexagonal crystal structure c and the length ratio c / a
And the Ar concentration in the underlayer film and the magnetic film were changed. At this time, the value of Brδ was 5 Gμm or more and 30 Gμm or less, and Hc was 1000 Oe or more and 3500 Oe or less.

FIG. 5 shows the lattice constant ratio c / a of the magnetic film and H
k, head flying height 0.03 μm, linear recording density 200
The relationship between the recording / reproducing S / N values in kPBI is shown. When the lattice constant ratio c / a is 1.3 or more and 1.6 or less, H
The value of k is 7 kOe or more and 20 kOe or less, and S / N
Shows a good characteristic of 1 or more. When the Ar concentration in the underlayer and the magnetic film is 0.01 atomic% or more and 5 atomic% or less, the value of Hk is 8 kOe or more and 20 kOe or less,
The S / N ratio was 1.2 or more, which was a better characteristic.

As a result of X-ray diffraction analysis of the magnetic recording medium formed by the method of this example, the crystals were oriented in the Cr underlayer so that the (100) crystal lattice plane of the body-centered cubic structure was substantially parallel to the substrate surface. It was confirmed that it was growing. Further, in the magnetic layer, the (110) plane of the hexagonal structure was oriented so as to be substantially parallel to the disk substrate surface. The center line average roughness Ra of the protective film surface was 1.0 nm, and the center line average roughness Ra of the magnetic film surface was 0.5 nm.

Using the medium of this example, the flying height is 0.03.
At the μm, the GMR head is 10
As a result of 10,000 seeks, it was confirmed that contact between the head and the medium did not occur. This effect is mainly composed of Cr, Mo, W, Nb, or Ta, and Pt, Pd, Si, F
Even when an alloy underlayer film in which at least one element selected from e, V, Ru, P, and B is added in an amount of 1 atomic% or more and 30 atomic% or less with a film thickness of 5 nm or more and 500 nm or less is similarly recognized. It was

[Embodiment 4] Outer diameter 48 mm, inner diameter 12 m
The surface of the Si-C substrate having a thickness of 0.3 mm and a thickness of 0.3 mm was smoothly polished using a lapping machine until the centerline average roughness Ra was 0.3 nm, washed and dried. This disk substrate was held in a vacuum in a sputtering apparatus by using an exhaust pump having an evacuation rate of water vapor per volume of a vacuum chamber of 500 l / s or more, and the substrate temperature was heated in the range of 100 ° C. to 400 ° C., after which Xe of 1 mTorr was applied. Ni underlayer under pressure
-B is formed to a thickness of 50 nm, and then Co-Ni-Pt-Ta is formed.
A magnetic film having a thickness of 10 nm was formed. At this time, the values of the residual magnetic flux density film thickness product Brδ are changed by changing the concentrations of Pt and Ta in the magnetic film within the range of 1 atomic% to 30 atomic% and the magnetic film thickness within the range of 1 nm to 40 nm. Was changed in the range of 1 Gm or more and 200 Gm or less.

FIG. 6 shows the relationship between Brδ and coercive force Hc.
Hc is 1 when Brδ is 5 Gμm or more and less than 80 Gμm
It was 000 Oe or more and 3500 Oe or less. Further, the recording / reproducing S / N at a head flying height of 0.02 μm and a linear recording density of 250 kPBI has a Brδ of 5 Gμm or more, 80
When it is less than Gμm, it becomes 1 or more, and Brδ is 5Gμ.
When m or more and 30 Gμm or less, the medium noise was remarkably reduced and the S / N became 1.2 or more. Furthermore, the Xe concentration in the underlayer film and the magnetic film was controlled by controlling the DC bias voltage during film formation in the range of -10V to -500V. As a result, the Xe concentration was 0.01 atom% or more and 5 atom% or more. In the following cases, the value of Hk was 10 kOe or more and 20 kOe or less, and the S / N ratio was 1.5 or more, showing further excellent characteristics.

[Embodiment 5] Outer diameter 65 mm, inner diameter 20 m
The surface of the TiO ₂ substrate having a thickness of 0.3 mm and a thickness of 0.3 mm was smoothed by a lapping machine until the centerline average roughness Ra became 0.3 nm, washed and dried. After that, using a tape polishing machine, in the presence of a diamond abrasive having an average abrasive grain size of 1 μm or less, the polishing tape is pressed against both sides of the disk surface while rotating the disk substrate through a contact roll, so that the depth and density of the substrate surface are increased. Formed irregular texture grooves. Further, dirt such as abrasives attached to the substrate was washed and dried. The center line average roughness Ra of the groove on the substrate surface measured in the radial direction is 0.
The average density of the grooves having a depth of 1 nm or more and 50 nm or less was 100 at a distance of 7 nm and a distance of 1 μm in the direction substantially perpendicular to the head traveling direction.

The disk substrate was vacuum-held in a sputtering apparatus by using an exhaust pump having an exhaust rate of water vapor per volume of the vacuum chamber of 500 l / s or more, and the substrate temperature was set to 100.
0.1mTorr after heating in the range of ℃ to 400 ℃
Under a Kr pressure in the range from 1 to 5 mTorr, Ru was formed to a thickness of 10 nm as a first-layer underlayer film, and then Cr-5Si alloy was formed to a thickness of 10 nm as a second-layer underlayer film. A Co-Cr-Ta magnetic film having a thickness of 5 nm was formed on this composite underlayer. At this time, the value of Brδ was 20 Gμm. By controlling the substrate temperature and the Kr partial pressure during film formation, the density of the face-centered cubic crystal lattice in the magnetic film crystal was controlled.
Hc at this time was 1000 Oe or more and 3500 Oe or less.

FIG. 7 shows the face centered cubic lattice type crystal lattice density,
Hk, head flying height 0.02 μm, linear recording density 25
The relationship between the values of recording / reproducing S / N at 0 kPBI is shown.
As the substrate temperature during film formation is increased and the Kr partial pressure is decreased, the face-centered cubic lattice type crystal lattice density is reduced. When the face-centered cubic lattice type crystal lattice density is 0.01% or more and 5% or less. , Hk is 7 kOe or more and 20 kOe or less,
The S / N ratio was 1 or more, indicating good characteristics. Furthermore, by controlling the DC bias voltage during film formation in the range of −10 V to −500 V, the Kr concentration in the underlayer and the magnetic film was controlled. As a result, the Kr concentration was 0.01 atomic% or more and 5 atomic% or more. In the following cases, the value of Hk was 10 kOe or more and 20 kOe or less, and the S / N ratio was 1.2 or more, showing further excellent characteristics.

As a result of the X-ray diffraction analysis of the magnetic recording medium formed by the method of this example, the Cr-Si underlayer was crystallized so that the (110) crystal lattice plane of the body-centered cubic structure was substantially parallel to the substrate surface. It was confirmed that the grains were oriented and grown. Moreover, in the magnetic layer, the (100) plane of the hexagonal structure was oriented so as to be substantially parallel to the surface of the disk substrate. The center line average roughness Ra of the protective film surface was 1.0 nm, and the center line average roughness Ra of the magnetic film surface was 0.9 nm.

Using the medium of this embodiment, the flying height is 0.02.
At the μm, the GMR head is 10
As a result of 10,000 seeks, it was confirmed that contact between the head and the medium did not occur. This effect is achieved by using Zr as the first underlayer film,
Si, Sc, A, C, Ge, Sb, Ga, Ru, P
d, V, Nb, Ta, Hf, Rh, Ni-P, Ni-B
Alternatively, Zr-Ta, Si-containing these as main components
C, Sc-V, Al-Mg, V-Fe, Nb-Cr, T
The same was found when alloys such as a-Cr, Hf-Zr, and Ta-Mo were used.

[Embodiment 6] Four magnetic recording media having the same characteristics as those of the media shown in Embodiments 1 to 5 were used, and Co-
A composite thin-film magnetic head having Ni-Fe or Co-Ta-Zr alloy as a recording magnetic pole material and a GMR element in a reproducing portion, and a thin-film head having a servo Ni-Fe alloy as a recording / reproducing magnetic pole. A magnetic recording device was manufactured by combining the above. As shown in a plan view 8 (a) and an AA ′ cross-sectional view 8 (b), this apparatus includes a magnetic recording medium 81, a magnetic recording medium drive unit 82, a magnetic head 83, and a magnetic head drive unit 8.
4. The recording / playback signal processing system 85 and other components.

Using this magnetic recording device, when the average time until an error occurred at a spacing of 0.03 μm was obtained, it was 2-3 times that of the conventional device, demonstrating extremely high reliability. did it. Further, since the magnetic recording device prototyped in this example has a low head flying height, the phase margin in recording / reproducing a signal is wide, and the areal recording density is 10 when the flying height is 0.12 μm using the medium of the comparative example. It was possible to provide a compact and large-capacity magnetic recording device that can be doubled in size.

When reproducing with a GMR head having a track width of 2 μm or less using this apparatus, the S / N is 1 or more at a high recording density of 200 kBPI or more, and the overwriting (O / W) characteristic is 26 dB or more. A capacitive magnetic recording device was obtained. In particular, even at a high recording density of 10 kTPI or higher, the medium of the present example sufficiently bleeds in the track width direction, so that a high S / N was obtained. Also, since the texture shape of the substrate surface is small, the quality of the servo signal is high, and good head positioning was possible. Similar effects were obtained when the servo head was a composite head.

In the present embodiment, the case of using the thin film magnetic head having the magnetic pole material of Co--Ni--Fe or CoTaZr alloy has been described. However, the NiFe, Fe--Al alloy magnetic film, or the multilayer magnetic film using them. Recording / reproducing separated thin-film magnetic head having recording magnetic pole material, CoTaZ
Metal with r, FeAlSi alloy, etc. provided in the gap
In-gap (MIG) recording / reproducing composite magnetic head,
Furthermore, it was confirmed that the same effect was obtained when an inductive thin film head or MIG head was used.

[0066]

According to the present invention, a GMR having high reproduction sensitivity
It is possible to provide a magnetic recording medium having a high S / N suitable for a head and capable of being floated by a GMR head with a flying height of 0.1 μm or less, a manufacturing method thereof, and a small-sized and large-capacity magnetic recording device using the same.

[Brief description of drawings]

FIG. 1 is a sectional structural view of a thin film magnetic recording medium according to the present invention.

FIG. 2 is a sectional structural view of a thin film magnetic recording medium of one embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between an anisotropic magnetic field Hk of a thin film magnetic recording medium of one embodiment of the present invention and S / N at the time of recording / reproducing.

FIG. 4 is a graph showing the width of the grain boundary of the magnetic film crystal of the thin film magnetic recording medium according to the embodiment of the present invention, the coercive force Hc, and S at the time of recording / reproducing.
The figure which shows the relationship with / N.

FIG. 5 is a diagram showing the relationship between the lattice constant ratio c / a of the magnetic film of the thin film magnetic recording medium of one embodiment of the present invention, the anisotropic magnetic field Hk, and the S / N during recording / reproduction.

FIG. 6 is a diagram showing a relationship between a residual magnetic flux density film thickness product Brδ and a coercive force Hc of a thin film magnetic recording medium according to an example of the present invention.

FIG. 7 shows the density of the face-centered cubic lattice type crystal lattice in the magnetic film crystal of the thin film type magnetic recording medium of one embodiment of the present invention, the anisotropic magnetic field Hk, and the S / N at the time of recording / reproducing. The figure which shows a relationship.

FIG. 8 is a sectional structural view of a magnetic recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

11 ... Magnetic disk substrate, 12, 12 '... Non-magnetic plating layer, 13, 13' ... Metal base film, 14, 14 '... Metal magnetic film, 15, 15' ... Non-magnetic protective film, 21 ... Non-magnetic protective film , 22 ... Metal magnetic film, 23 ... Non-magnetic underlayer film, 24 ... Magnetic disk substrate, 25 ... Protective film etching section, 81 ... Magnetic recording medium, 82 ... Magnetic recording medium drive section, 83 ... Magnetic head, 84 ... Magnetic head Drive unit, 85 ... Recording / reproducing signal processing system

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Yasuo Yaku 1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. Central Research Laboratory, Mfg. Co., Ltd. (72) Inventor Manwakazu Igarashi 1-280, Higashikoigakubo, Kokubunji, Tokyo Metropolitan Research Center, Hitachi, Ltd.

Claims (21)

[Claims] 1. A magnetic recording medium comprising a non-magnetic disk substrate and at least one magnetic film formed on the non-magnetic disk substrate directly or via at least one underlayer film, the magnetic film being measured in a head traveling direction. The value of the product Brδ of the residual magnetization Br and the total film thickness δ of the magnetic film is 5 Gμm.
As described above, the magnetic recording medium is less than 80 Gμm and the anisotropic magnetic field Hk of the medium is 7 kOe or more and 20 kOe or less. 2. The value of Brδ is 5 Gμm or more and 30 Gμm.
The magnetic recording medium according to claim 1, wherein: 3. A coercive force of 1000 Oe or more and 3500 Oe.
3. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is e or less. 4. The magnetic recording medium according to claim 1, 2 or 3, wherein the grain boundary width of the magnetic film crystal is 0.5 nm or more and 5 nm or less. 5. The magnetic film has a substantially hexagonal crystal structure, the c-axis of the magnetic film is oriented substantially in the in-plane direction of the substrate, and the hexagonal lattice constants a and c are used. Ratio of length c / a
5. The magnetic recording medium according to claim 1, wherein the value of is 1.3 or more and 1.6 or less. 6. The magnetic film has a substantially hexagonal crystal structure, and the density of stacking faults forming a face-centered cubic lattice present in the magnetic film crystal is 5% or less. The magnetic recording medium according to claim 1. 7. Ar, X in the magnetic film and / or underlayer film
At least one element of e and Kr is 0.01% or more, 5
% Of the atomic concentration is present or less.
7. The magnetic recording medium according to any one of claims 6 to 6. 8. Cr, Mo, W, V, Ta, Nb, Z
A film thickness of 0.5 nm or more and 5 n containing at least one of r, Ti, B, Be, C, Ni-P, and Ni-B as a main component.
8. The magnetic recording medium according to claim 1, wherein the magnetic film is multi-layered into two or more layers via a non-magnetic intermediate layer of m or less. 9. The center line average roughness measured in the direction perpendicular to the head running direction on the surface of the magnetic film is 0.3 nm or more and 1.9.
The magnetic recording medium according to claim 1, wherein the magnetic recording medium has a thickness of not more than nm. 10. A magnetic film according to claim 1, wherein a protective film is provided on the magnetic film, and the protective film has a larger surface roughness than the surface of the magnetic film. recoding media. 11. The center line average roughness Ra measured in the direction perpendicular to the head running direction on the surface of the protective film is 0.3 nm or more,
The magnetic recording medium according to claim 10, which has a thickness of 3 nm or less. 12. A thin film containing Cr, Mo, W, Nb or Ta as a main component between the non-magnetic disk substrate and the magnetic film, and
An alloy underlayer film containing at least one element selected from i, Pt, Pd, Si, Fe, V, Ru, P and B is formed adjacent to the magnetic film and has a thickness of 5 nm or more, 50
It is 0 nm or less, The magnetic recording medium of any one of Claims 1-11 characterized by the above-mentioned. 13. The base film is composed of at least two non-magnetic films, and the base film on the substrate side is Zr, Si, Ti, S.
c, Al, C, Ge, Sb, Ga, Ru, Pd, V, N
13. The magnetic recording medium according to claim 1, which is b, Ta, Hf, Rh, Ni-P or Ni-B, or an alloy containing any of these as a main component. 14. The magnetic film is a Co—Cr—Ta system, Co—
The magnetic recording medium according to any one of claims 1 to 13, which comprises a Cr-Ni-based or Co-Cr-Pt-based alloy as a main component. 15. The substrate is an Al—Mg alloy, chemically strengthened glass, organic resin, Ti, Si, carbon, or TiO ₂ ,
15. The magnetic recording medium according to claim 1, wherein the magnetic recording medium is made of ceramics such as SiC. 16. A method of forming a magnetic film on a non-magnetic disk substrate by a sputtering method.
16. The method for manufacturing a magnetic recording medium according to claim 5, wherein a negative bias voltage of 10 V or more and 500 V or less is applied to the nonmagnetic disk substrate in the step. Manufacturing method of magnetic recording medium according to item 17. A base film made of a non-magnetic material is formed on a non-magnetic disk substrate by a sputtering method.
16. The method of manufacturing a magnetic recording medium according to claim 1, further comprising: 16. The method of manufacturing a magnetic recording medium according to claim 1, wherein a negative bias voltage of 10 V or more and 500 V or less is applied to the non-magnetic disk substrate in the first step and the second step. 18. A magnetic recording device comprising a magnetic recording medium, a magnetic recording medium driving means, a magnetic head having a giant magnetoresistive effect element as a reproducing means, a magnetic head driving means, and a recording / reproducing signal processing means. The flying height of the head is 0.1 μm or less, and the product B of the residual film thickness Br of the magnetic film in the magnetic recording medium and the total film thickness δ measured in the head traveling direction.
The value of rδ is 5 Gμm or more and 80 Gμm or less, and the value of the anisotropic magnetic field Hk of the medium is 7 kOe or more, 2
A magnetic recording device characterized by being 0 kOe or less. 19. The magnetic recording medium has a linear recording density of 150 k.
The magnetic recording device according to claim 18, wherein the magnetic recording medium has a BPI or more. 20. The recording track density of a magnetic recording medium is 1
The magnetic recording device according to claim 18, wherein the magnetic recording device has a recording capacity of 0 kTPI or more. 21. A magnetic recording medium according to claim 1, a magnetic recording medium driving means, a magnetic head having a magnetic recording / reproducing section, a magnetic head driving means, and a recording / reproducing signal processing means. And a magnetic recording device including.