JPH07235034A - Perpendicular magnetic recording medium and magnetic recording / reproducing apparatus - Google Patents

Abstract

(57) [Summary] [Object] The present invention can improve the cotton density by decreasing the perpendicular magnetic recording medium having a large saturation magnetization, the perpendicular magnetic anisotropy and the coercive force and a small magnetic dispersion and the spacing. A magnetic recording / reproducing device is provided. The present invention is a perpendicular magnetic recording medium having a CoPt alloy-based magnetic thin film formed on a substrate, the magnetic thin film comprising a CoPt alloy crystal phase (2), a Co oxide phase, and a nitride. And a compound phase (3) selected from the group consisting of a phase and a carbide phase. A magnetic recording / reproducing apparatus using this recording medium is also provided.

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 recording / reproducing apparatus.

[0002]

2. Description of the Related Art Since a magnetic thin film containing Co as a main component has a large saturation magnetic flux density and crystal magnetic anisotropy, it is becoming the mainstream as a magnetic thin film for a magnetic recording medium. In particular, by utilizing the large anisotropy energy of this magnetic thin film,
It has been considered to form a perpendicular magnetic film suitable for ultra high density recording. As a result of recent research, in order to improve the coercive force and medium S / N ratio of such a Co-based perpendicular magnetization film, it is necessary to form a film structure that divides the magnetic interaction of Co-based crystal grains. It is becoming clear that there is.

Further, in a perpendicular magnetic recording medium having a two-layer structure in which a soft magnetic film having a high magnetic permeability is provided on a substrate and a perpendicular magnetic film is provided on the soft magnetic film, which is higher than that of a perpendicular magnetic recording medium having only a perpendicular magnetic film. It is known that the better recording and reproducing characteristics are exhibited by the interaction between the head and the soft magnetic film (for example,
JP-A-52-78403). Therefore, in the case of a perpendicular magnetic recording medium, it is common to provide a soft magnetic underlayer (backing layer) under the perpendicular magnetization film.

Conventionally, as a Co-based perpendicularly magnetized film,
(1) The most prominent CoCr alloy film, or N
i, Ta, Pt added, (2) Co-CoO film formed by vacuum deposition in an oxygen atmosphere (for example, Japanese Patent Laid-Open No. 59-162622), (3) CoPt formed by sputtering ( Cr) alloy film (Proceedings of the 14th Annual Meeting of the Japan Society for Applied Magnetics, 8pB-11,199)
0), (4) CoPtBO film (Japanese Patent Laid-Open No. 3-5831)
6), (5) There is known a laminated film of Co and Pt (Japanese Unexamined Patent Publication No. 80421/1993) which has been studied mainly for magneto-optical recording media.

The perpendicular magnetization films (1) to (5) will be described in more detail below. (1) In the pure Co film, the shape magnetic anisotropy energy based on the thin film shape is larger than the crystal magnetic anisotropy energy. On the other hand, in a CoCr alloy film in which Cr is added to Co, the segregation of Cr in the Co grain boundaries reduces the magnetic interaction of the Co grains, resulting in a decrease in shape magnetic anisotropy and a certain degree of coercive force. Expected to increase. However, since Cr also mixes into Co crystal grains, the crystal magnetic anisotropy is lower than that of pure Co, and the saturation magnetization amount is also lower. Therefore, in order to obtain a perpendicularly magnetized film by increasing the degree of decrease in shape magnetic anisotropy rather than the degree of decrease in crystalline magnetic anisotropy, C
It is necessary to increase the addition amount of r. The saturation magnetization amount of such a film containing a large amount of Cr is about 1/4 of that of a pure Co film, which is extremely small.

In the case of the perpendicular recording medium, unlike the in-plane recording medium, the surface magnetic flux density of the medium cannot be increased by increasing the film thickness, so that the saturation magnetization amount of the film is large in order to obtain high output. is necessary. However, for the above reason, even if a CoCr perpendicularly magnetized film can be produced, a high output cannot be obtained because the saturation magnetization amount is small.

(2) In the Co-CoO film, the Co grain density decreases, and the formation of antiferromagnetic CoO mainly having a Neel point near room temperature in the Co grain boundaries forms Co.
Since the magnetic interaction between the crystal grains is reduced, a certain increase in coercive force can be expected. When the film thickness of the Co—CoO film is large, it is expected that the columnar crystals add shape magnetic anisotropy energy. The Co-CoO film is C
The saturation magnetization is larger than that of the oCr film.

However, since Co has a strong bond with oxygen,
When actually manufactured, the growth of (002) oriented crystal grains is unlikely to occur. As a result, the crystalline magnetocrystalline anisotropy is significantly reduced, the crystal orientation is also likely to be deteriorated, and a large coercive force cannot be obtained.

At the same time that the crystal magnetic anisotropy is significantly reduced, the crystal magnetic anisotropy is different between the crystal grains, so that the film has a large anisotropy dispersion. Especially, since the Neel point of CoO is near room temperature, when the operating temperature of the medium is lower than room temperature, a bias magnetic field is eventually applied to the Co crystal. In this case, non-uniformity of the CoO crystal such as crystal orientation causes local non-uniformity of the bias magnetic field, resulting in increased magnetic dispersion of the film.

Further, the crystal orientation deteriorates, that is, C
As a result, the C axis of o becomes difficult to be oriented perpendicular to the substrate, and as a result, the perpendicular magnetic anisotropy energy is only comparable to the in-plane magnetic anisotropy energy, and the characteristics as a perpendicular magnetization film cannot be obtained sufficiently.

(3) The CoPt (Cr) alloy film has a large saturation magnetization amount, and the perpendicular magnetic anisotropy energy can be increased by optimizing the sputtering conditions. Pt
The perpendicular magnetic anisotropy energy is larger than that of pure Co when the added amount is 30 at% or less, which is a characteristic not seen when other added elements are used.

However, in this film, the magnetic interaction between crystal grains is strong and the perpendicular coercive force is small. Therefore, there is a drawback that the low frequency output is low. (4) The CoPtBo film is obtained by adding B to CoPt and forming the film in an oxygen atmosphere. This film also has a large amount of saturation magnetization.

However, since this film is likely to be in the fcc phase and perpendicular magnetic anisotropy is generated based on the shape magnetic anisotropy,
It is necessary to increase the film thickness. Further, the film is easily oxidized by the addition of B, and the crystal orientation is likely to be disturbed, as in the case of the Co—CoO film. Therefore, it is necessary to maintain the crystal orientation by using a base film such as Pt.

In the case of a perpendicular magnetic recording medium, it is general to provide a soft magnetic underlayer under the perpendicular magnetization film as described above. However, if the thickness of the perpendicular magnetization film is increased or an underlayer for controlling the crystal orientation is used, the spacing between the head and the soft magnetic underlayer is increased, resulting in a decrease in interaction. (5) In a film in which Co and Pt are sequentially stacked, the anisotropic energy is considered to be caused by the interface effect between Co and Pt.

[0015]

In the perpendicularly magnetized film described above, it is necessary to control the state of the interface. Therefore, it is necessary to avoid conditions that disturb the interface state,
For example, it is difficult to increase the film forming speed. Further, since this film has a laminated structure, the average saturation magnetization amount of the film is small, which is about the same as that of the CoCr film.

In addition to the above-mentioned problems, it is desired in the future to reduce the spacing in order to increase the recording density. In the thin film magnetic recording medium, a protective film of C or the like having a thickness of about 20 nm is formed in preparation for collision with the head. However, if the flying height is made smaller than Rmax that represents the unevenness of the medium surface in order to reduce the spacing, the medium and the head are in constant contact. In this case, a thicker protective film is required, so that the spacing cannot be reduced.

When a recording / reproducing experiment is performed using the above-described perpendicular magnetic recording medium having a two-layer structure, spike noise is observed. This spike noise is not observed when a recording / reproducing experiment is performed using a recording medium having a single-layer structure composed of only perpendicularly magnetized films. The spike noise is not generated by the interaction between the soft magnetic underlayer and the perpendicular magnetic film laminated thereon, but is generated only by the soft magnetic underlayer. Further, it is known that this noise does not occur uniformly in the medium, that there are many domain walls where noise is generated, and that there are no domain walls where noise does not occur (Japanese Patent Publication No. 53,686). This noise is caused by the irreversible transition of the domain wall, and is generally called Barkhausen noise. From the above, in order to suppress the Barkhausen noise, it is necessary to suppress the generation of the magnetic domain wall in the soft magnetic underlayer, but no suitable means for solving this has been heretofore known.

Further, in order to obtain even better recording / reproducing characteristics, it is an important issue to construct a magnetic recording / reproducing apparatus in which a perpendicular magnetic recording medium and a recording / reproducing head are optimally combined.

It is an object of the present invention to provide a perpendicular magnetic recording medium which has a large amount of saturation magnetization, perpendicular magnetic anisotropy and coercive force and has little magnetic dispersion at room temperature and low temperature. Another object of the present invention is to provide a perpendicular magnetic recording medium that is less damaged by collision and sliding with the head.

Another object of the present invention is to provide a perpendicular magnetic recording medium capable of effectively suppressing Barkhausen noise caused by domain wall movement in a soft magnetic underlayer, and having high sensitivity and high resolution recording and reproduction. To provide. Still another object of the present invention is to provide a magnetic recording / reproducing apparatus which can obtain good recording / reproducing characteristics.

[0021]

The perpendicular magnetic recording medium of the first invention comprises a substrate and a crystal phase of a CoPt-based alloy and a Co oxide, a Co nitride, and a Co carbide formed on the substrate. And a perpendicular magnetization film containing a compound phase selected from the group.

A perpendicular magnetic recording medium of the second invention of the present application has a substrate and a perpendicular magnetic film made of a Co-based alloy, which is formed on the substrate and has two peaks in the oxygen concentration distribution on the surface. Is.

A perpendicular magnetic recording medium according to the third invention of the present application is a substrate and a Co film containing 1 to 15 at% of at least one of adsorbed oxygen and adsorbed nitrogen formed on the substrate.
And a perpendicular magnetization film made of a system alloy.

The perpendicular magnetic recording medium of the fourth invention is the first to the first.
An underlayer is provided between the substrate and the perpendicular magnetization film of the recording medium of the third invention. The perpendicular magnetic recording medium of the fifth invention has an underlayer and a nonmagnetic film provided between the substrate and the perpendicular magnetization film of the recording medium of the first to third inventions.

A perpendicular magnetic recording medium according to a sixth aspect of the present invention is the recording medium of the fifth aspect, in which the underlayer has a laminated structure of a soft magnetic film and an antiferromagnetic film. The perpendicular magnetic recording medium of the seventh invention comprises a substrate and a Co-based (CoPt, CoCr, CoNi
Etc.) A base layer is provided in a laminated structure of a soft magnetic film and an antiferromagnetic film between a perpendicular magnetization film.

The magnetic recording / reproducing apparatus of the eighth invention of the present application is selected from the group consisting of a substrate, a crystal phase of a CoPt-based alloy, and a Co oxide, a Co nitride, and a Co carbide formed on the substrate. A perpendicular magnetic recording medium having a perpendicular magnetization film containing a compound phase, a recording head for magnetizing the perpendicular magnetization film of the perpendicular magnetic recording medium in the perpendicular direction to record a signal, and a magnetic resistance for reading the recorded signal. And an effective reproducing head (hereinafter referred to as MR head).

A magnetic recording / reproducing apparatus of the ninth invention of the present application has a substrate and a perpendicularly magnetized film made of a Co-based alloy formed on an outer substrate and having two peaks in the oxygen concentration distribution on the surface. The magnetic recording medium includes a magnetic recording medium, a recording head that records a signal by vertically magnetizing a perpendicularly magnetized film of the perpendicular magnetic recording medium, and an MR head that reads a recorded signal.

[0028]

The present invention will be described in more detail below. First application
In the perpendicular magnetization recording medium of the invention of claim 1, the perpendicular magnetization film is CoPt.
Crystal phase of Co-based alloys, Co oxide, Co nitride and Co
And a compound phase selected from the group consisting of carbonaceous materials. As shown in FIG. 1, a perpendicular magnetization film 1 formed on a substrate 11 includes an hcp phase CoPt columnar crystal grain 2 in which the C axis is oriented perpendicular to the film surface, and an hcp phase CoPt.
It is composed of a compound phase 3 selected from the group consisting of Co oxide, Co nitride, and Co carbide existing at the grain boundaries of the columnar crystal grains 2.

CoPt constituting this perpendicular magnetization film
Cr, Mo, W, V, Nb, Ta, Ti,
At least one element selected from the group consisting of Zr and Hf may be added. Further, when the compound phase is made of Co oxide, that is, CoO, it is preferable that the crystal orientation is (lll) orientation perpendicular to the film surface. This CoO phase may contain Pt or another third element as long as its antiferromagnetism is not disturbed.

The perpendicularly magnetized film having the structure as shown in FIG. 1 is produced by forming a CoPt-based alloy film in an inert gas by a vacuum deposition method or a sputtering method, and then subjecting it to oxidation, nitriding or carbonization treatment. can do.

The CoPt film has a large saturation magnetization and a large crystal magnetic anisotropy energy. This film has a Pt concentration of 3
A perpendicular magnetization film is obtained by orienting (002) perpendicularly to the film surface at 0 at% or less. Further, by oxidizing, nitriding or carbonizing the crystal grain boundaries to form a compound phase, the magnetic interaction between the CoPt crystal grains is reduced and the coercive force is increased. Since this film has a very large perpendicular magnetic anisotropy, and the perpendicular magnetic anisotropy is generated based on the crystal magnetic anisotropy, a film having a thickness of 100 nm or less is a good perpendicular magnetization film.

In addition, C, Cr, Mo, W, V,
When at least one element selected from the group consisting of Nb, Ta, Ti, Zr, and Hf is added, CoP is added.
The crystal grains of the t-based alloy can be refined. As the crystal grains become finer, the magnetization rotation of the magnetic particles approaches the ideal simultaneous magnetization rotation. As a result, the coercive force can be increased and the medium nozzle can be lowered.

Further, when the compound is CoO, C
When oO is oriented perpendicularly to the film surface (111), even if it becomes antiferromagnetic at low temperature, the bias magnetic field given to the CoPt crystal is uniform and the anisotropic dispersion does not increase.

In the perpendicular magnetic recording medium of the second invention, the perpendicular magnetization film is a Co type alloy such as CoPt, CoNi, CoC.
It is composed of r and has two peaks in the oxygen concentration distribution on its surface. The oxygen concentration distribution on the surface is measured as follows. EDX using analytical electron microscope
Thus, the oxygen concentration in each minute region is examined so that the surface of the magnetic thin film is divided into minute regions each having a size of several nm square in a grid pattern. Then, an oxygen concentration distribution map showing the ratio of the area of the minute region having a certain oxygen concentration to the total area analyzed is created. In the perpendicularly magnetized film according to the second invention of the present application, minute regions occupying a large area ratio in this oxygen concentration distribution diagram are concentrated near two points on the oxygen concentration axis,
It has two peaks. Among these, the minute region having a relatively high oxygen concentration corresponds to the crystal grain boundary, and the minute region having a relatively low oxygen concentration corresponds to the inside of the crystal grain.

In this perpendicular magnetization film, the region having a relatively high oxygen concentration corresponding to the crystal grain boundary reduces the magnetic interaction between the grains. Therefore, it is possible to suppress the decrease in the coercive force of the film due to the magnetization reversal caused by the interaction acting between a large number of particles, and the coercive force of individual particles can be effectively used.

Unlike the conventional magnetic thin film having an oxide phase, such as a Co--CoO film, this perpendicularly magnetized film does not contain much oxygen in the crystal grains that exhibit magnetism, so that the crystal magnetic anisotropy, It is difficult for the crystal orientation and the saturation magnetic flux density to decrease. On the other hand, when a small amount of oxygen is added to this region, it is possible to prevent the magnetization from easily reversing due to the movement of the domain wall, and to prevent non-uniform magnetization reversal within the particles. As a result, the coercive force of individual particles can be increased. The occurrence of a peak in the oxygen concentration distribution means that the dispersion of oxygen concentration is small and the magnetic properties of each particle are uniform.

Here, it is preferable that the oxygen concentration of the region corresponding to the crystal grain boundary is 15 at% or more, and the oxygen concentration of the region corresponding to the inside of the crystal grain is 1 to 15 at%. This is for the following reasons. That is, if the oxygen concentration in the region corresponding to the crystal grain boundary is less than 15 at%, the coercive force cannot be increased. Regarding the oxygen concentration in the region corresponding to the inside of the crystal grains, when the oxygen concentration exceeds 15 at%, the crystal orientation tends to be remarkably deteriorated and the perpendicular magnetic anisotropy tends to decrease, and conversely, when it is less than 1 at%, the coercive force decreases. .

Such a perpendicularly magnetized film can be produced by the following method. In principle, a Co-based target is sputtered in a sputtering atmosphere containing oxygen to obtain a relatively high energy and a relative amount. It suffices to generate two kinds of sputtered particles having extremely low energy. Such two kinds of sputtered particles may be generated at the same time or may be generated alternately in a short time. However, it is preferable to alternately generate two kinds of sputtered particles over time like the latter. Two kinds of sputtered particles having different energies have different bondability with oxygen. That is, sputtered particles having lower energy are more likely to bond with oxygen. Therefore, a region containing a large amount of oxygen can be formed in a region formed with sputtered particles having low energy, and a film containing almost no oxygen can be formed in a region formed with sputtered particles having high energy.

More specific methods include the following methods. A method of alternately changing the pressure of a rare gas / oxygen mixed gas used as a sputtering gas to a high pressure and a low pressure, a method of alternately changing the sputtering power to a high output and a low output, and a sputtering gas and a target 2
Method of setting the sputter power of each sputter gas to different values in combination, and two kinds of rare gas as sputter gas.
A method of using an oxygen mixed gas (one of which may be a rare gas only), a method of alternately changing the distance between the sputtering gas and the substrate to a short distance and a long distance, and two sputtering gases having different distances from the substrate. There is a method of using.
As described above, sputtered particles having different energies can be generated depending on the difference in the thickness of the sputtered Ar, the sputter power, the type of rare gas for sputtering, the distance between the sputter gun and the substrate.

As described above, the perpendicularly magnetized film having two peaks in the oxygen concentration distribution on the surface is excellent in the perpendicular magnetic recording medium because the magnetocrystalline anisotropy and the crystal orientation are less likely to deteriorate.

Further, in the present invention, at least one of the adsorbed and bound oxygen and the adsorbed and bound nitrogen is 1 to 15a.
A perpendicularly magnetized film containing t% may be used. Unlike oxygen bound to Co, adsorbed oxygen or nitrogen does not significantly reduce the saturation magnetization of the film. Moreover, since stress is generated in the CoPt particles to increase the hardness of the film and it is difficult to move dislocations within the particles, plastic deformation can be suppressed even when stress occurs due to contact between the perpendicular magnetization film and the head. Here, regarding the content of the adsorbed and bound oxygen or the adsorbed and bound nitrogen, if the content is less than 1 at%, the hardness of the film is insufficient and scratches are likely to occur at the time of contact with the head. Cracks are likely to occur at the time of contact with the head.

A specific structure of the perpendicular magnetic recording medium according to the present invention will be described with reference to the drawings. In the perpendicular magnetic recording medium of the present invention, for example, as shown in FIG. 1 described above, the perpendicular magnetic film 1 may be simply provided on the substrate 11. Although not shown, a protective film may be provided on the perpendicular magnetization film 1, and a lubricating film may be further provided on the protective film. However, when the perpendicular magnetization film has sufficient hardness, it is not always necessary to provide a protective film or a lubricating film.

The perpendicular magnetic medium according to the present invention may have a structure in which a soft magnetic underlayer 12 and a perpendicular magnetization film 1 are provided on a substrate 11, as shown in FIG. Further, as shown in FIG. 3, in addition to the structure of FIG. 2, a structure in which a non-magnetic film for suppressing exchange interaction between the soft magnetic underlayer and the perpendicular magnetization film is provided, that is, a substrate. 11 / Soft magnetic underlayer 12 /
The structure of non-magnetic film 13 / perpendicular magnetization film 1 may be used. As the soft magnetic film that can be used, CoZrNb, Co
FeTa, NiFe, Fe-C, and the like are included, but are not limited thereto.

The configuration of the perpendicular magnetic recording medium capable of suppressing Barkhausen noise may be as follows. For example, in the disk-shaped perpendicular magnetic recording medium shown in FIG. 4, the soft magnetic film 12 and the antiferromagnetic film 1 are formed on the substrate 11.
4, the perpendicular magnetization film 1 and the protective film 15 are sequentially laminated. That is, the underlayer has a laminated structure of a soft magnetic film and an antiferromagnetic film. This structure utilizes exchange coupling between the antiferromagnetic film and the soft magnetic film to apply a bias magnetic field larger than the soft magnetic coercive force in the direction (radial direction) orthogonal to the track direction to eliminate the domain wall. It is a thing. In the medium of FIG. 4, since the spacing between the surface of the soft magnetic film and the head may be large and the recording / reproducing characteristics may be deteriorated, the antiferromagnetic film / soft magnetic underlayer / A medium is also known in which a perpendicular magnetic film is formed in this order to improve recording / reproducing characteristics.

However, in the perpendicular magnetic recording medium of FIG. 4, when the thickness of the soft magnetic underlayer is large, the bias magnetic field is lowered. However, since the film thickness of the soft magnetic underlayer affects the resistance of the magnetic circuit composed of the head and the medium, a certain amount of film thickness is necessary, especially for high density recording with a large saturation magnetization and coercive force. For the perpendicular magnetic recording medium, the soft magnetic underlayer needs to be thick in order to generate a sufficient recording magnetic field. Therefore, with the structure of FIG. 4, it is difficult to apply a bias magnetic field sufficient to eliminate the generation of domain walls. For example, a film thickness of 1.5μ on the substrate
When the CoZrNb film of m is formed and the FeMn film is formed thereon, the bias magnetic field is small and the domain wall cannot be eliminated.

On the other hand, the perpendicular magnetic recording medium having the structure shown in FIG. 5 is more advantageous than the structure shown in FIG. 4 in applying a bias magnetic field to the soft magnetic film. In this medium, the underlayer has a laminated structure of a soft magnetic film and an antiferromagnetic film. In other words, it has a structure in which the soft magnetic film forming the underlayer is divided by at least one antiferromagnetic film. The antiferromagnetic film has a function of eliminating the domain wall by applying a bias magnetic field larger than the soft magnetic coercive force in a direction (radial direction) orthogonal to the track direction by exchange coupling with the soft magnetic film. As the film provided for the purpose of applying the bias magnetic field as described above, in addition to the antiferromagnetic film, for example, an in-plane oriented high coercive force magnetic film or an artificial lattice film can be used. Hereinafter, a film having such an action is referred to as a bias film.

The disk-shaped perpendicular magnetic recording medium shown in FIG. 5 will be described more specifically. On the glass substrate 11, 15 soft magnetic films 12 made of CoZrNb and 15 antiferromagnetic films 14 made of FeMn each having a thickness of 20 nm are alternately formed on the glass substrate 11. On top of that, a soft magnetic film 12 having a thickness of 100 nm and a non-magnetic film 1 made of Ti having a thickness of 10 nm are formed.
Perpendicular magnetization film made of CoPtO with a thickness of 3,60 nm 1,
A protective film 15 made of SiO ^{2 having a} thickness of 5 nm is formed. The bias magnetic field is applied in the radial direction of the disc.

The soft magnetic film 12 forms a magnetic circuit together with the head, efficiently applies a large magnetic field to the perpendicular magnetization film 1 during recording, and uses the magnetomotive force of the perpendicular magnetization film 1 as magnetic flux during reproduction. It has the effect of efficiently passing through.
Further, due to the exchange coupling between the antiferromagnetic film 14 and the soft magnetic film 12, a bias magnetic field is applied to the soft magnetic film 12 and the generation of domain walls is suppressed. In this case, Co that contacts FeMn
By optimizing the film thickness of ZrNb to about 100 nm,
The magnetic permeability of the CoZrNb film can be maintained at 1000 or more. If the CoZrNb film is too thick, the magnitude of the bias magnetic field is insufficient and noise cannot be reduced. On the other hand, if the CoZrNb film is too thin, the magnetic resistance increases (the magnetic permeability decreases), and the reproduction output decreases. As described above, in the structure in which the soft magnetic film is divided by the bias film, one bias film and adjacent ones are formed.
The magnitude of the bias magnetic field is determined by the film thickness of the soft magnetic film of the layer, and the magnitude of the magnetic resistance is independently determined by the total film thickness of the soft magnetic film. Therefore, noise reduction and output increase can be suppressed independently.

As the antiferromagnetic film, NiO, CoO or the like can be used in addition to FeMn. Also,
As the bias film, besides the antiferromagnetic film, a high coercive force film such as CoPt having in-plane anisotropy, CoFe / Cu
You may use the artificial lattice film, such as. When the artificial lattice film is used, the bias magnetic field can be made uniform to reduce noise.

Since the soft magnetic film closest to the substrate has a strong influence on the bias direction of the entire medium, it is possible to align the bias direction by using a soft magnetic film of NiFe or the like having a slightly lower saturation magnetic flux density if necessary. Sometimes required. In this case, by using a plurality of types of soft magnetic films in the medium, it is possible to increase the saturation magnetic flux density of the entire medium and cope with high density recording. Also, the strength of the bias magnetic field can be changed in the thickness direction by changing the film thickness of each layer or the type of the bias film according to the magnetic field distribution of the head.
Further, when the soft magnetic film formed under the film forming conditions with good productivity becomes thick and vertical anisotropy is likely to occur, the film thickness per layer may be thinned. When the magnetic permeability decreases, a non-magnetic film or a film having a small amount of magnetization may be sandwiched between the antiferromagnetic film and the soft magnetic film.

A recording / reproducing head which can be suitably used for the perpendicular magnetic recording medium of the present invention as described above will be described with reference to FIGS. 6 to 10. In each of these figures, for ease of explanation, a perpendicular magnetic recording medium having a structure in which a soft magnetic underlayer 12, a nonmagnetic layer 13, and a perpendicular magnetization film 1 are sequentially formed on a substrate 11 is used. .

FIG. 6 shows a magnetic head 100 having a yoke type MR reproducing head. A reproduction return yoke 102 is formed at the end of the arm 101. The magnetic poles 103, 104 for reproduction and the bridge M between them are provided on the outer side of the magnetic poles.
An R film 105 is provided. These members are covered with an insulating material 106. The lower ends of the reproducing return yoke 102 and the reproducing magnetic pole 104 face the surface of the medium 10. Further, a recording main magnetic pole 107 is formed on the outer side thereof. A protrusion is formed in the center of the main magnetic pole 107, and a recording coil 108 is provided around the protrusion. Further, a recording return yoke 109 is formed so as to face the protrusion at the center of the main magnetic pole 107. These members are covered with an insulating material 110. Main pole 1
07 and the lower ends of the return yoke 109 face the surface of the medium 10.

FIG. 7 shows a magnetic head 100 having a shield type MR reproducing head. DC at the end of arm 101
The magnetic shield film 111 and the nonmagnetic film 112 made of CoZrNb are formed by the sputtering method. An MR film 113 made of NiFe is formed on the outer side by an ion beam sputtering method. The lower end of the MR film 113 faces the surface of the medium 10. A nonmagnetic film 114, a magnetic shield film 115, and a nonmagnetic film 116 are formed outside the MR film 113. The outer surface of the non-magnetic film 116 is smoothed, and the main magnetic pole 117 for recording made of FeSi is formed on this surface. This main pole 11
The lower end of 7 faces the surface of the medium 10. Main pole 11
A protrusion is formed at the center of 7, and a recording coil 118 is provided around the protrusion. Recording coil 11
8 is covered with an insulating material 119.

FIG. 8 shows a magnetic head 100 having a dual type MR reproducing head. At the end of the arm 101, M
An R film 121, an insulating material 122, an MR film 121, and an insulating material 123 are formed. The pair of MR films 121 face each other, and their lower ends face the surface of the medium 10. A main magnetic pole 124 for recording is formed on the outer side thereof. A protrusion is formed on the upper portion of the main magnetic pole 124, and a recording coil 125 is provided around the protrusion. A recording return yoke 126 is formed so as to face the protrusion of the main magnetic pole 124. This member is covered with an insulating material 127. The lower ends of the main magnetic pole 124 and the return yoke 126 face the surface of the medium 10.

FIG. 9 shows a magnetic head 100 having a dual type MR reproducing head different from that of FIG. In FIG.
The difference from FIG. 8 is that the pair of MR films 121 facing each other.
That is, the soft magnetic films 131 are formed on the surface opposite to the surface opposite to. The lower side of the soft magnetic film 131 faces the surface of the medium 10. With such a configuration, the MR film 121 is exchange-coupled with the soft magnetic film 131.

FIG. 10 shows a recording / reproducing integrated magnetic head 10.
Indicates 0. A pair of main magnetic poles 141a, 1 made of CoFe
41b are provided so as to sandwich the nonmagnetic layer 142 made of Ti. A recording coil 144 covered with an insulating material 143 is arranged around the main magnetic poles 141a and 141b. In the case of this example, the number of turns of the recording coil 144 is three.
It's a turn. The lower ends of the main magnetic poles 141 a and 141 b are arranged so as to face the medium 10. Main pole 141
An insulating layer 145 and an MR film 146 made of permalloy are provided on the upper side of a and 141b. MR film 14
The film surface of 6 is parallel to the surface of the medium 10. Two lead wires 147 are connected to both ends of the MR film 146, and a sense current flows from the leads 147 to the MR film 146.

In the magnetic recording / reproducing apparatus having the above magnetic head, recording and reproduction are performed as follows. At the time of recording, a strong magnetic flux is generated in the main pole by supplying a recording current to the recording coil. At this time,
Due to the magnetic coupling between the main magnetic pole and the soft magnetic underlayer 12 of the medium 10, a large and sharp distribution recording magnetic field is generated inside the perpendicular magnetization film 1 sandwiched between them, and the perpendicular magnetization film 1 is magnetized. .

During reproduction, a constant sense current is passed through the MR film. When the magnetic transition of the perpendicular magnetization film 1 passes through the front surface of the MR film, the magnetic flux passing from the perpendicular magnetization film 1 through the MR film 102 changes, so that the electrical resistance changes sharply. This resistance change can be converted into a voltage change and obtained as a reproduction signal voltage.

Since the magnetic recording / reproducing apparatus of the present invention is a combination of a medium having a large saturation magnetization and a perpendicular magnetic anisotropy and a perpendicular recording head, it can generate a steep recording magnetic field and has a higher density. It is possible to record.

Further, since the perpendicular magnetic film has high hardness, the protective film can be made thin, and the distance between the head and the perpendicular magnetic film and the distance between the head and the surface of the underlayer can be reduced. As a result, a device with higher efficiency, higher resolution and higher reliability can be provided.

Further, since the perpendicularly magnetized film contains a phase having a low electric conductivity, the electric resistance of the medium becomes high. Therefore, when the protective film is very thin or absent, even if the MR reproducing head comes into contact with the medium, the sense current does not flow in the medium and the signal does not deteriorate. Further, as in the yoke type MR reproducing head shown in FIG. 6, a magnetic flux circulates through the medium and the reproducing head, and a device using a reproducing system having a small magnetic circuit resistance can obtain a particularly large reproducing output.

[0062]

Embodiments of the present invention will be described below with reference to the drawings. Example 1 C was formed by the DC magnetron sputtering method as follows.
An oPr film was formed. Glass having a thickness of 0.7 mm as a substrate and Co 20 at% Pt with a diameter of 5 inches as a target
Each alloy is used and the distance between the substrate and the target is 10
It was set to 0 mm or more and installed in a DC magnetron sputtering device. Substrate temperature is set to room temperature and ultimate pressure is 4 × 10
^It was evacuated to ^-5 Pa. First, the substrate was cleaned by rf reverse sputtering for 90 seconds in a pure Ar atmosphere of 2 Pa. After that, sputtering is performed in a pure Ar atmosphere of 3 Pa at a sputtering power of 120 kW for 3 minutes to obtain a film thickness of 50 m.
A CoPt film of m or less was formed.

With respect to the obtained magnetic thin film, the saturation magnetization amount I
The S was 1.5 T and the holding power was 210 Oe. According to a torque meter measurement, this film is a perpendicular magnetization film,
The perpendicular magnetic anisotropy energy was 1080 kJ / m ³ . The C-axis dispersion angle Δθ ₅₀ of CoPt was 6 deg.

Next, this film was heat-treated in the atmosphere at 300 ° C. for 1.5 hours. AES (Auger elec)
As a result of the tron spectroscopy analysis, O, C, Co, Cl, Pt,
N was detected. Further, as a result of performing AES analysis while etching with Xe ions, after 1 minute, O, Co,
C was detected, Co, O, Pt, N was detected 8 minutes later, and Co, O, Pt, Si, N was detected 14 minutes later.

Focusing on the oxygen concentration, the oxygen concentration was higher than the Co concentration in the surface layer, but the oxygen concentration was slightly lower and the C concentration was higher on the outermost surface. It was confirmed that the oxygen concentration decreased from the surface layer toward the inside and increased again near the substrate. Judging from the etching rate, the film thickness of the oxide layer on the surface is thinner than 20 nm. On the other hand, focusing on the nitrogen concentration, the nitrogen concentration is low on the surface,
It was expensive inside. However, it was confirmed that the oxygen concentration was higher than the nitrogen concentration even in the region where the oxygen concentration was the lowest.

FIG. 11 shows the XRD (X- of the heat-treated film.
ray diffraction). As shown in this figure, the peaks assigned to the Co oxide and the Co
A peak indicating that the C-axis of Pt was oriented perpendicular to the substrate was detected. The peak of Co oxide is STA
The angle is shifted to a lower angle side than the reflection angle obtained from the M card, indicating that Pt is mixed. Further, since the (002) reflection peak of CoPt has a widened skirt on the low angle side, it can be seen that there is a region where the lattice is spread in the thickness direction. Even after the oxide layer on the surface is removed by etching, the peak of Co (Pt) O does not disappear although it decreases in intensity.
Was confirmed to exist. At this time, C of CoPt
The dispersion angle Δθ ₅₀ of the shaft was 6 deg or less, which was low dispersion. Further, as shown in FIG. 12, CoO (111)
The dispersion angle Δθ ₅₀ of the peaks attributed to the plane was 7 deg or less, which was low dispersion.

FE-SEM (Field emission)
type-secondary electron m
As a result of the observation by an electron microscope, it was confirmed that the surface was rougher than the particles before the heat treatment but fine particles having a diameter of 10 nm appeared by etching.

When the film after etching was observed with a transmission electron microscope, the crystal structure of Co (Pt) O was confirmed at the grain boundary of CoPt. In addition, this film was subjected to EDX (Energy disper) using a super-resolution analytical electron microscope.
sire method in X-ray Spec
As a result of the trocopy analysis, it was confirmed that the CoPt crystal grain boundaries contained a large amount of oxygen.

FIG. 13 shows the I-H loop of this membrane.
The saturation magnetization of this film was 1.2 T, and the coercive force was 500 Oe, which was higher than that before the heat treatment. On the other hand, the in-plane squareness ratios S and S ^* are 0.22 and 0.3, respectively.
2, which is not increased as compared with that before the heat treatment. The magnitude of perpendicular magnetic anisotropy energy of this film is 580 kJ / m.
^3, which is lower than that before heat treatment. However, the ratio of the perpendicular magnetic anisotropy energy in the thin film shape to the in-plane magnetic anisotropy energy is from 0.17 before heat treatment to 0.
It has increased to 54.

Next, a soft magnetic underlayer of (Co ₉₀ Fe ₁₀ ) ₉₂ Ta ₈ having a thin film of 0.5 μm and a C nonmagnetic film having a thickness of 10 nm or less were sequentially formed on the glass substrate, and then the above method was used. A perpendicular magnetic film made of CoPtO was formed to manufacture a perpendicular magnetic recording medium having the structure shown in FIG. The non-magnetic film is provided to prevent exchange interaction between the soft magnetic underlayer and the perpendicular magnetization film.

For comparison, the film thickness is 0.5 on the glass substrate.
After forming a soft magnetic underlayer of CoFeTa having a thickness of μm, a conventional perpendicular magnetization film and a protective film having a film thickness of 20 nm were formed, and a perpendicular magnetic recording medium (Comparative Example 1) was manufactured. The conventional perpendicular magnetization film used here has a saturation magnetization of 0.6 T.
Hereinafter, the coercive force is 1600 Oe or less and the perpendicular magnetic anisotropy energy is 150 kJ / m ³ or less.

A magnetic recording / reproducing apparatus was produced by combining each of the above-mentioned media and a head having a single magnetic pole perpendicular recording head and a yoke type MR reproducing head shown in FIG. Recording and reproduction were performed using these devices, and the recording density characteristics and medium S / N characteristics were examined. At this time, the track width was set to 4 μm or less, and the flying height of the head was set so that the distance between the head tip surface and the soft magnetic underlayer surface was 0.09 μm or less. In addition,
When the flying height is small as described above, contact between the head and the medium may occur. As a result, the device of this example is the same as that of Comparative Example 1.
The recording density characteristics and the S / N characteristics were superior to those of the above. In particular, the device of this example produced a larger output at a recording density of 100 kFCI or more than the device of Comparative Example 1.

For comparison, a soft magnetic underlayer (Fe
A medium (Comparative Example 2) having a two-layer structure of (Ni) / conventional perpendicular magnetization film (CoCr) and having no protective film was prepared. Recording / reproduction was performed on the medium of the present example and the comparative example 2 at a low flying height at which contact between the head and the medium might occur.
As a result, the device of this example is
The reliability against head crash was excellent.

The medium of this embodiment can obtain various effects even when combined with the head shown in FIGS. For example, in the medium of this example, the perpendicular magnetization film contains an oxide layer, so that the magnetic resistance of the medium surface is high. Therefore, even when a shield type MR reproducing head in which the end surface of the MR film faces the medium surface as shown in FIG. 7 is used and reproducing is performed with the head and the medium in contact with each other, the sense current of the MR head Can be reproduced with higher sensitivity and reliability without flowing into the medium. The same effect can be obtained when a dual type MR reproducing head in which the end surface of the MR film faces the medium surface as shown in FIG. 8 is used. Moreover, the recording resolution can be increased.

Further, the recording resolution can be increased also when a dual type MR reproducing head in which the MR film and the soft magnetic pole are exchange-coupled as shown in FIG. 9 is used. Further, as shown in FIG.
When a head in which the R reproducing head is integrated is used, there is no track deviation between recording and reproducing, so that the track density can be increased.

Similar to FIG. 5, a perpendicular magnetic recording medium in which the underlayer has a laminated structure of a soft magnetic pole and an antiferromagnetic film, and a nonmagnetic film and the perpendicular magnetization film of this embodiment are formed on the underlayer, You may produce. In this medium, a bias magnetic field larger than the coercive force is applied to the soft magnetic film in the radial direction, and as a result, generation of domain walls is suppressed. Therefore, in the device in which this medium and the recording / reproducing head are combined, noise can be reduced and a high-quality signal can be obtained, and reliability can be improved. Further, in this case, when CoFeTa is used as the soft magnetic film, the crystallinity is good and the soft magnetic property is good, so that the crystallinity of the thin antiferromagnetic film is also good, and both a large bias magnetic field and a high magnetic permeability are obtained. Can be achieved.

In the present embodiment, the case where the protective film is not provided on the medium surface has been described, but a protective film may be formed to further emphasize reliability, and a lubricating film may be further formed on the protective film. Also, a film for strengthening the adhesive force may be formed between the substrate and the underlayer. In this case, even if the underlayer is thick, film peeling does not occur when the head collides with the medium surface. Therefore, the reliability of the device can be improved.

Example 2 C was formed by the DC magnetron sputtering method as follows.
An oPt film was formed. Glass having a thickness of 0.7 mm as a substrate and Co 20 at% Pt with a diameter of 5 inches as a target
5 at% Ti alloy was used, and the distance between the substrate and the target was set to 100 mm or more, and the alloy was set in a DC magnetron sputtering apparatus. The substrate temperature was set to room temperature, and the substrate was evacuated to an ultimate pressure of 4 × 10 ⁻⁵ Pa. First, 2Pa
The substrate was cleaned for 90 seconds by rf reverse sputtering in a pure Ar atmosphere. Then, in a pure Ar atmosphere of 3 Pa, sputtering was performed for 3 minutes at a sputtering power of 120 kW to form a CoPtTi film having a film thickness of 48 nm.

With respect to the obtained magnetic thin film, the saturation magnetization amount I
s was 1.26T and coercive force was 726 Oe. According to a torque meter measurement, this film was a perpendicular magnetization film, and the perpendicular magnetic anisotropy energy was 1008 kJ / m 3.

Next, this film was heat-treated in the atmosphere at 300 ° C. for 1.5 hours. As a result of the AES analysis, O, C, Co, Cl, Pt, Ti, N were detected on the surface of the heat-treated film. Further, as a result of performing the AES analysis while etching with Xe ions, O was observed after 1 minute. , Co, T
i, C were detected, and after 8 minutes, Co, O, Pt, Ti,
N was detected, and after 14 minutes, Co, O, Pt, Ti, S
i, N was detected.

Focusing on the oxygen concentration, the oxygen concentration was higher than the Co concentration in the surface layer, but the oxygen concentration was low and the C concentration was high in the outermost surface. It was confirmed that the oxygen concentration decreased from the surface layer toward the inside and increased again near the substrate. Judging from the etching rate, the film thickness of the oxide layer on the surface is thinner than 20 nm. On the other hand, focusing on the nitrogen concentration, the nitrogen concentration is low on the surface,
It was expensive inside. However, it was confirmed that the oxygen concentration was higher than the nitrogen concentration even in the region where the oxygen concentration was the lowest.

As a result of XRD analysis of the heat-treated film,
A peak attributed to the oxide and a peak indicating that the C-axis of CoPtTi is oriented perpendicular to the substrate were confirmed. The peak of Co oxide is shifted to a lower angle side than the reflection angle obtained from the STAM card, and P
It shows that t and Ti are mixed. Also, C
Since the hem of the (002) reflection peak of oPtTi is wide on the low angle side, it can be seen that there is a region where the lattice is wide. Even after the oxide layer on the surface is removed by etching, the peak of Co (Pt, Ti) O does not disappear but disappears in the film, and Co (Pt, Ti) O also remains in the film.
It was confirmed that O was present.

The C-axis dispersion angle Δθ ₅₀ of CoPtTi is 8d.
It was eg, and was slightly spread as compared with the film to which Ti was not added. Similarly, Co (Pt, Ti) O (11
1) The dispersion angle Δθ _{50 of} the peak belonging to the plane is also 9.5 deg.
And spread a little. In addition, the hcp phase CoPtTi (0
02) Half-width of reflection ΔI (002) is 0.300 deg
And was wider than the film to which Ti was not added.
From this, it was confirmed that the crystal grain size was miniaturized. At this time, the half-value width of Co (Pt, Ti) O (111) reflection is 0.403 deg, and CoPtTi (00
2) It was confirmed that the half-width of reflection was larger and the crystal grain size of Co oxide was smaller.

As a result of the FE-SEM observation, it was confirmed that the surface was rougher than before the heat treatment but fine particles smaller than 10 nm in diameter appeared by etching.

Observation of the film after etching with a transmission electron microscope revealed that Co (Pt,
The crystal structure of Ti) O was confirmed. In addition, when this film was subjected to EDX analysis using a super-resolution analytical electron microscope,
It was confirmed that a large amount of oxygen was contained in the crystal grain boundary of CoPtTi.

The saturation magnetization of this film is 0.775.
The coercive force was 1002 Oe, which was higher than that before the heat treatment. This value is higher than that of the film to which Ti is not added. On the other hand, the in-plane squareness ratios S and S ^* are each 0.2
2 and 0.32, which are not increased as compared with those before the heat treatment. The magnitude of the perpendicular magnetic anisotropy energy of this film is 651 kJ / m ^3, which is lower than that before the heat treatment.
However, the ratio of the perpendicular magnetic anisotropy energy in the thin film shape to the in-plane magnetic anisotropy energy increased from 1.20 before the heat treatment to 1.85.

The film of this embodiment was formed from NiFe and CoZrN.
The medium formed on the soft magnetic film of b, Fe-C, CoFe, etc. is superior in reliability to recording density, medium S / N ratio, low flying height recording or contact recording as compared with the conventional medium. . Therefore, the recording density exceeds 100 kFCI,
It is particularly suitable for a high recording density magnetic recording device having a track width of less than 4 μm.

Next, NiFe and CoZr were formed on the glass substrate.
A soft magnetic underlayer made of Nb, Fe-C, CoFe, etc.,
After a nonmagnetic film having a film thickness of 10 nm or less was sequentially formed, a perpendicular magnetization film made of CoPtTiO was formed by the above method to manufacture a perpendicular magnetic recording medium having the structure shown in FIG.

A magnetic recording / reproducing apparatus was manufactured by combining this medium with a single-pole perpendicular recording head shown in FIG. 6 and a head having a yoke type MR reproducing head. Recording and reproduction were performed using these devices, and the recording density characteristics and medium S / N characteristics were examined. As a result, the apparatus of the present embodiment has a recording density, S /
Excellent reliability in N ratio, extremely low flying recording or contact recording. In particular, the output was large when the recording density was 100 kFCI or more.

In this example, Ti was added to CoPt, but Cr, Mo, W, V, Nb,
Even when Ta, Ti, Zr, and Hf were added, the particle size was smaller and the coercive force was larger than when not added. However, when these elements were added at 10 at% or more, the crystal magnetic anisotropy and the crystal orientation were likely to deteriorate.

Example 3 Co at 20% Pt alloy with Ti at 2 at% and 5 at, respectively.
%, 8 at%, and 11 at% were added, and CoPtTi was formed by DC magnetron sputtering.
A membrane was prepared. With respect to the obtained four types of magnetic thin films, the saturation magnetization amounts are 1.4, 1.3, 1.2 and 1.1 T, respectively.
Perpendicular magnetic anisotropy field is 9.5-6kOe, coercive force is 15
It was 0 to 230 Oe.

Next, these four types of films were heat-treated in the atmosphere at 300 ° C. for 3 hours. According to XRD analysis
It was confirmed that CoO was generated in all the films.
When the crystal grain size of these films was observed using a field emission SEM, the grain size became smaller as the amount of Ti added increased, and the grain size decreased from 10 nm to 5 nm. Regarding the four kinds of heat-treated magnetic thin films, the saturation magnetization amounts are 1.1, 1.0, 0.9, 0.8 T, the perpendicular magnetic anisotropy magnetic fields are 9, 10, 9, 8 kOe, and the coercive force is It was 600,1000,650,550 Oe, respectively. It can be seen that the coercive force of any of the films is increased compared to 500 Oe of the film after the heat treatment of Example 1 in which Ti is not added. FIG. 14 shows an I-H loop of the film in which the amount of Ti added is 5 at%.

In place of Ti, Cr, Mo, W,
Even when V, Nb, Ta, Ti, Zr, and Hf were added, the particle size was smaller and the coercive force was larger than when not added. However, if these elements are added too much, the crystal magnetic anisotropy and the crystal orientation are likely to deteriorate.

Example 4 Using a Co20% Pt5at% Ti alloy target, D
A CoPtTi film was formed by the C magnetron sputtering method. The saturation magnetization of the obtained magnetic thin film was 1.3.
T, perpendicular magnetic anisotropy magnetic field is 10 kOe, coercive force is 180
It was Oe.

This film was placed in the atmosphere at 150 ° C. for 2 hours.
It heat-processed at 25 degreeC, 300 degreeC, 370 degreeC, or 450 degreeC for 3 hours. The crystal orientation of CoO differs depending on the heat treatment conditions, and the film heat-treated at 300 ° C is the most (111).
The orientation was strong. These films were measured I-H loop by VSM in liquid N ₂ temperature. Each I-
When the shapes of the H loops were compared, it was found that the better the orientation of CoO, the stronger the tension of the IH loop. Table 1 shows the relationship between the heat treatment conditions and the crystal orientation of CoO of the obtained film and the tension of the shoulder of the I-H loop.

[0096]

[Table 1]

It is known that the less the magnetic dispersion, the stronger the tension of the shoulder of the I-H loop. Therefore, C
It can be seen that a film with less magnetic dispersion can be produced by improving the orientation of oO.

An R / W test was carried out in a low thermostatic bath using a medium using such a film. As a result, CoO becomes (1
11) The oriented medium is recording resolution, output, medium S
Both of the / N ratios were excellent.

Example 5 Co20% Pt5% Ti alloy was used as a target,
A CoPtTi film was formed by the DC magnetron sputtering method. The obtained film has a saturation magnetization of 1.5 T,
The perpendicular magnetic anisotropy magnetic field was 8 kOe and the coercive force was 150 Oe. Further, according to the measurement by the torque meter, this film is a perpendicular magnetization film, and the perpendicular magnetic anisotropy energy is 1
It was 200 kJ / m ³ . The C-axis dispersion angle Δθ ₅₀ of CoPt was 6 deg.

This film was heated at 300 ° C. in an N ₂ atmosphere.
And heat treated for 1.5 hours. When XRD analysis of this film was performed, peaks attributed to Co ₂ N and Co ₃ N were recognized. The perpendicular magnetic anisotropy field of the heat-treated film was 10 kOe and the coercive force was 480 Oe, which were higher than those before the heat treatment. At this time, the dispersion angle Δθ ₅₀ of C-axis of CoPt is 6d
The dispersion remained as low as eg.

Example 6 The same CoPtTi film as obtained in Example 5 was replaced with CO
Was heat-treated at 300 ° C. for 1.5 hours in an atmosphere containing. XRD analysis of this film revealed that Co ₂ C and Co
A peak attributed to ₃ C was observed. The heat-treated film has a perpendicular magnetic anisotropy field of 10 kOe and a coercive force of 5
It was 50 Oe, which was larger than that before the heat treatment. At this time, CoP
The dispersion angle Δθ ₅₀ of the C axis of t was 6 deg, which was low dispersion.

Example 7 The same CoPtTi film as obtained in Example 5 was adjusted to pH
It was left for 3 hours at 25 ° C. in 6.8 H ₂ O. When XRD analysis of this film was performed, a peak attributed to CoO (111) was observed. With respect to the film after the treatment, the perpendicular magnetic anisotropy magnetic field was 10 kOe and the coercive force was 550 Oe, which were higher than those before the treatment. At this time, CoPt C-axis dispersion angle Δ
The θ ₅₀ remained as low as 6 deg. In addition, CoO
The dispersion angle Δθ _{50 of} the peak attributed to the (111) plane is also 7 de
g and low dispersion.

Example 8 C was formed by the DC magnetron sputtering method as follows.
The oPt film was formed. Glass that has undergone chemical strengthening treatment as a substrate, Co 20% P with a diameter of 5 inches as a target
Each t-alloy is used, and the distance between the substrate and target is 1
It was set to 50 mm and installed in a DC magnetron sputtering device. The substrate temperature was set to room temperature, the total sputtering pressure was set to 4 Pa, the sputtering power was set to 1 kW per 5 inch diameter, and sputtering was performed to form a CoPt film having a film thickness of 50 nm. At this time, Ar gas and 0.01% oxygen-containing A were used as sputtering gas.
Two kinds of R gas were used and alternately switched 20 times during sputtering. In this experiment, the sputtering time T [Ar + 0] with Ar / oxygen mixed gas was used in the total sputtering time T [t].
Was changed variously.

FIG. 15 shows T [Ar + 0] / T [t],
The relationship between the magnetic properties of the film, that is, the perpendicular coercive force, the in-plane coercive force, the saturation magnetization amount Is, and the squareness ratios S and S ^* is shown. Figure 1
From 5 it can be seen that: T [Ar + 0] / T
When [t] is 0.2 or more, an increase in perpendicular coercive force is recognized. As the coercive force increases, the ratio S of the residual magnetization amount to the in-plane saturation magnetization amount also increases. On the other hand, the saturation magnetization tends to decrease. However, for example, T [Ar + 0] / T
The film formed under the condition that [t] is 0.4 has a high perpendicular coercive force of 1700 Oe and a squareness ratio S in the in-plane direction of 0.
It is as low as 3 or less, and the saturation magnetization is sufficiently large as 1.1T.

FIG. 16 shows the relationship between T [Ar + 0] / T [t] and the perpendicular magnetic anisotropy energy (Kp = Ku ^exp + Is ² / 2μ _o ) measured by a magnetic torque meter. The film formed under the condition that T [Ar + 0] / T [t] is 0.4 is a perpendicular magnetization film having a Kp of 900 kJ / m ³ .

As a result of AES analysis, O, C,
Co, Pt, Cl, N were detected. Further, AES analysis was performed while etching with Xe ions. Focusing on the oxygen concentration, the oxygen concentration in the surface layer is higher than the Co concentration, but the oxygen concentration in the outermost surface is slightly lower than that in the C concentration.
The concentration was high. It was confirmed that the oxygen concentration decreased from the surface layer toward the inside and increased again near the substrate. Judging from the etching rate, the film thickness of the oxide layer on the surface is thinner than 5 nm. It was confirmed that the nitrogen concentration was lower than the oxygen concentration in every region.

As a result of XRD analysis, a peak indicating that the C-axis of CoPt was oriented perpendicular to the substrate was detected. In addition, since the (002) reflection peak of CoPt has an asymmetric shape in which the skirt is widened on the low angle side from the wide angle side, there is a region where the lattice spreads in the C-axis direction and has distortion. Recognize. At this time, the C-axis dispersion angle Δθ ₅₀ of CoPt was as low as 8 deg or less.

As a result of observing this film by FE-SEM, it was confirmed that the film was composed of fine particles having a diameter of 15 nm or less. As a result of observing this film with a transmission electron microscope,
It was confirmed that it was composed of crystal grains having a diameter of 15 nm or less and an amorphous phase. The proportion of the amorphous phase was 50% or less of the total area.

About this film, an analytical electron microscope (Ana
lytical electronmicroscop
y) using EDX, and its surface is in a grid pattern with a number of n
The oxygen concentration of each micro area was examined so that the micro area was divided into micro areas of size m. FIG. 17 shows the ratio of the area of a region having a certain oxygen concentration to the total area analyzed.
(Hereinafter, such a figure is referred to as an oxygen concentration distribution). From this figure, it can be seen that the oxygen concentration distribution on the surface of the film has two peaks. It is considered that the minute region having a high oxygen concentration corresponds to the grain boundary because it is amorphous, and the minute region having a low oxygen concentration corresponds to the inside of the crystal grain.

On the other hand, for comparison, according to the prior art, an experiment of forming a CoPt film at a total pressure of 2 Pa using only Ar / oxygen mixed gas as a sputtering gas was performed by changing the oxygen concentration in the sputtering gas. went. In this case, the perpendicular coercive force tended to increase as the oxygen concentration was increased. However, a film having a perpendicular coercive force of 1300 Oe or more cannot be used as a perpendicular magnetization film because the in-plane squareness ratios S and S ^* increase.

FIG. 18 shows the result of examining the oxygen concentration distribution on the surface of this film in the same manner as in FIG.
As shown in FIG. 18, in a film formed by using a single mixed gas of Ar and oxygen, the oxygen concentration distribution on the surface has only one peak, and oxygen is dispersed almost uniformly. I understand.

When reflection X-ray diffraction was measured for the film of this example having two peaks in the oxygen concentration distribution as shown in FIG. 17, separation of peaks was observed in correspondence with the peak of oxygen concentration.

Next, a C film having a thickness of 0.5 μm was formed on the glass substrate.
After a soft magnetic underlayer made of oFeTa and a non-magnetic film having a thickness of 10 nm or less were sequentially formed, a perpendicular magnetic film was formed by the above method, and a perpendicular magnetic recording medium having the structure shown in FIG. 3 was produced. For comparison, the perpendicular magnetic recording medium of Comparative Example 1 described above was used.

A magnetic recording / reproducing apparatus was manufactured by combining each of the above-mentioned media with a head having a single magnetic pole perpendicular recording head and a yoke type MR reproducing head shown in FIG. Recording and reproduction were performed using these devices, and the recording density characteristics and medium S / N characteristics were examined. At this time, the track width was set to 4 μm or less, and the flying height of the head was set so that the distance between the head tip surface and the soft magnetic underlayer surface was 0.09 μm or less. In addition,
When the flying height is small as described above, contact between the head and the medium may occur. As a result, the device of this example is the same as that of Comparative Example 1.
The recording density characteristics and the S / N characteristics were superior to those of the above. In particular, the device of this example produced a larger output at a recording density of 100 kFCI or more than the device of Comparative Example 1. Further, the apparatus of the present embodiment was excellent in reliability against head crash even when recording / reproducing was carried out at a low flying height where the contact between the head and the medium could occur.

Even when the medium of this embodiment is combined with the head shown in FIGS. 7 to 10, various effects similar to those described in Embodiment 1 can be obtained. As in FIG. 5, the underlayer has a laminated structure of a soft magnetic film and an antiferromagnetic film,
A perpendicular magnetic recording medium having a non-magnetic film and the perpendicular magnetization film of this embodiment formed thereon may be manufactured. In this medium,
As a result of applying a bias magnetic field larger than the coercive force in the radial direction to the soft magnetic film, the generation of domain walls is suppressed. Therefore, in the device in which this medium and the recording / reproducing head are combined, noise can be reduced and a high-quality signal can be obtained, and reliability can be improved. In this case, CoFe is used as the soft magnetic film.
When Ta is used, the crystallinity is good and the soft magnetic property is good, so that both a large bias magnetic field and a high magnetic permeability can be achieved.

In the present embodiment, the case where the protective film is not provided on the medium surface has been described. However, a protective film may be formed to further emphasize reliability, and a lubricating film may be further formed on the protective film. . Further, a film may be formed between the substrate and the underlayer to enhance the adhesive force. In this case, even if the underlayer is thick, film peeling does not occur when the head collides with the medium surface, so that the reliability of the device can be improved.

Although CoPt is used in this embodiment,
Similar effects were obtained with other Co alloys such as CoNi and CoCr. Example 9 C was formed by the DC magnetron sputtering method as follows.
An oPt film was formed. Glass subjected to chemical strengthening treatment as a substrate, Co 20% Pt with a diameter of 5 inches as a target
Each alloy is used and the distance between the substrate and the target is 15
It was set to 0 mm and installed in a DC magnetron sputtering device. Substrate temperature is room temperature, sputtering gas is 0.01%
Sputtering was performed using oxygen-containing Ar gas and the sputtering power was set to 1 kW per 5 inch diameter, and a CoP film with a thickness of 50 nm was formed.
A t film was formed. At this time, the sputtering pressure was alternately switched 20 times during the sputtering so that the sputtering pressure was 1 Pa or 10 Pa. This experiment was performed by changing the ratio of the time T [10 Pa] at which the sputtering pressure was 10 Pa to the total sputtering time T [t].

FIG. 19 shows T [10Pa] / T [t],
The relationship between the magnetic properties of the film, that is, the perpendicular coercive force, the in-plane coercive force, the saturation magnetization amount Is, and the squareness ratios S and S ^* is shown. Figure 1
The following can be seen from 9. T [10Pa] / T
When [t] is 0.2 or more, an increase in perpendicular coercive force is recognized. As the coercive force increases, the ratio S of the residual magnetization amount to the in-plane saturation magnetization amount also increases. On the other hand, the saturation magnetization tends to decrease. However, for example, T [10 Pa] / T
The film formed under the condition that [t] is 0.5 has a high perpendicular coercive force of 2500 Oe, a low residual magnetization ratio S in the inner surface direction of 0.3 or less, and a saturation magnetization amount of 0.8 T, which is sufficiently large. .

In FIG. 20, T [10Pa] / T [t] and
The relationship with the perpendicular magnetic anisotropy energy (Kp = Ku ^exp + Is ² / 2u ₀ ) measured by a magnetic torque meter is shown. The film formed under the condition that T [10 Pa] / T [t] is 0.5 is a perpendicular magnetization film having a Kp of 600 kJ / m ³ .

With respect to this film, the oxygen concentration of each minute region was examined by EDX using an analytical electron microscope so that the surface was divided into minute regions having a size of several nm in a substrate-like pattern. It was found that the ratio of the area of the region having a certain oxygen concentration to the total area analyzed was that the oxygen concentration distribution on the surface of the film had two peaks as in FIG. confirmed.

On the other hand, for comparison, according to the conventional technique, an experiment of forming a CoPt film by using Ar gas containing 0.01% oxygen as a sputtering gas was conducted while changing the total sputtering pressure. In this case, when the total sputter pressure was 3 Pa or more, the perpendicular coercive force tended to increase. However, a film having a perpendicular coercive force of 1300 Oe or more increases the in-plane squareness ratio to 0.5 and cannot be used as a perpendicular magnetization film. Further, in these films, the oxygen concentration distribution on the surface has only one peak, and it can be seen that oxygen is dispersed almost uniformly. When reflection X-ray diffraction was measured for the film of this example having an oxygen concentration distribution having two peaks, peak separation was observed corresponding to the oxygen concentration peak.

As in the case of Example 8, by laminating the soft magnetic film, the non-magnetic film and the perpendicular magnetization film of this Example on the substrate,
A perpendicular magnetic recording medium was produced. Furthermore, this medium is shown in FIG.
A device combined with the head shown in FIG. Then, when the recording / reproducing characteristics were evaluated by contact recording, the result that the linear recording resolution was high and the noise was small was obtained as compared with the one using the conventional medium. Other experiments conducted in the same manner as in Example 8 also gave the same results as in Example 8.

Example 10 C was formed by the DC magnetron sputtering method as follows.
An oPt film was formed. Chemically strengthened glass as a substrate, two 5 inch diameter Co 20% as a target
Using a Pt alloy (No. 1 and No. 2), the distance between the substrate and the target was set to 150 mm, and the Pt alloy was set in the DC magnetron sputtering apparatus. The substrate temperature was room temperature, Ar gas containing 0.01% oxygen was used as the sputtering gas, and the sputtering power was set to No. No. 1 is constant at 3.0 kW / 5 inch (W [1]), No. For 2, 0.06-3.
Sputtering was performed at a constant value (W [2]) of 0 kW / 5 inch to form a CoPt film having a film thickness of 50 nm.

In FIG. 21, W [2] / W [1] and the magnetic characteristics of the film, that is, the perpendicular coercive force, the in-plane coercive force, and the saturation magnetization I
The relationship between s and the squareness ratios S and S ^* is shown. As can be seen from FIG. 21, an increase in the perpendicular coercive force is recognized when W [2] / W [1] is around 0.3. The film formed under the condition that W [2] / W [1] is 0.3 has a perpendicular coercive force of 1500.
The Oe and saturation magnetization were 1.1T. When the perpendicular magnetic anisotropy energy Kp was measured with a magnetic torque meter, it was found that the perpendicular magnetic film had Kp = 900 kJ / m ³ .

With respect to this film, the oxygen concentration of each minute region was examined by EDX using an analytical electron microscope so that the surface was divided into minute regions having a size of several nm in a matrix pattern. It was found that the ratio of the area of the region having a certain oxygen concentration to the total area analyzed was that the oxygen concentration distribution on the surface of the film had two peaks as in FIG. confirmed.

On the other hand, for comparison, according to the prior art, N
o. The CoPt film was formed by using only the target No. 2 and changing the sputtering power variously. In this case, an increase in perpendicular coercive force was observed when the sputtering power was in the range of 0.08 to 2.0 kW. However, a film having an abnormal perpendicular coercive force of 1300 Oe has an in-plane squareness ratio of 0.5 and cannot be used as a perpendicular magnetization film. Further, in these films, the oxygen concentration distribution on the surface has only one peak, and it can be seen that oxygen is dispersed almost uniformly.

When the reflection X-ray diffraction was measured for the film of this example having an oxygen concentration distribution having two peaks, separation of the peaks was observed corresponding to the peak of the oxygen concentration. Even when one target and one sputter gun were used and the level of the sputter power was changed over time, the same results as in the present example were obtained.

As in the case of Example 8, by laminating the soft magnetic film, the non-magnetic film and the perpendicular magnetization film of this Example on the substrate,
A perpendicular magnetic recording medium was produced. Furthermore, this medium is shown in FIG.
A device combined with the head shown in FIG. Then, when the recording / reproducing characteristics were evaluated by contact recording, the result that the linear recording resolution was high and the noise was small was obtained as compared with the one using the conventional medium. Other experiments conducted in the same manner as in Example 8 also gave the same results as in Example 8.

Example 11 C was formed by the DC magnetron sputtering method as follows.
An oPt film was formed. Glass subjected to chemical strengthening treatment as a substrate, Co 20% Pt with a diameter of 5 inches as a target
The alloys are used and the distance between the substrate and target is 90
It was set to mm and installed in a DC magnetron sputtering device. The substrate temperature was set to room temperature, the total sputtering pressure was set to 4 Pa, the sputtering power was set to 1 kW per 5 inch diameter, and sputtering was performed to form a CoPt film having a film thickness of 50 nm. At this time, as sputtering gas, 0.01% oxygen-containing Xe gas and 0.01
% Oxygen-containing Ar gas was used, and the ratio of the two was changed.

FIG. 22 shows the pressure P of the Xe / oxygen mixed gas.
The ratio of [Xe + O] to the total pressure P [t], the magnetic properties of the film, that is, the perpendicular coercive force, the in-plane coercive force, the saturation magnetization Is,
And the squareness ratios S and S ^* are shown. The following can be seen from FIG. Vertical coercive force is P [Xe + O] /
P [t] increases in the range of 0.2 to 0.8. The in-plane coercive force increases when P [Xe + O] / P [t] is about 0.8. In-plane squareness ratio, S ^* is P [Xe + O]
The value of / P [t] is small up to 0.5, which is characteristic of the perpendicular magnetization film, and increases when P [Xe + O] / P [t] exceeds 0.5, and the characteristics of the in-plane magnetization film are strengthened. On the other hand, P [Xe +
The saturation magnetization tends to decrease as O] / P [t] increases.

FIG. 23 shows P [Xe + O] / P [t],
The relationship with the perpendicular magnetic anisotropy energy (Kp = Ku ^exp + Is ² / 2u ₀ ) measured by a magnetic torque meter is shown. Kp is 1 when only Ar / oxygen mixed gas is used
It shows a large value of 500 Oe. P [Xe +] / P [t]
Kp decreases as the saturation magnetization decreases, and Kp is almost zero when P “Xe + O] / P [t] is 0.8 or more.

From the above results, it can be seen that a film having a large perpendicular coercive force and an in-plane coercive force can be produced by forming a film using two kinds of gases. For example, PXe + O] / P
When [t] is 0.5, a saturation magnetization amount of 1 T or more, a perpendicular magnetic anisotropy energy of 700 kJ / m ³ , and a perpendicular coercive force of 2400 Oe can be obtained. In addition, P [Xe
When + O] / P [t] is 0.8, the in-plane coercive force is 175
An in-plane magnetized film of 0 Oe is obtained. Fig. 24 shows P [Xe +
The relationship between O] / P [t] and the Auger electron spectroscopic intensity ratio O / Co of oxygen and Co atoms by AES analysis is shown. This Auger electron spectral intensity ratio O / Co corresponds to the average oxygen concentration in the film. From this figure, P [Xe + O] /
It can be seen that the oxygen concentration increases as P [t] increases. For example, P [Xe + O] / P [t] is 0.
5, 0.125P [Xe + O] / P [t] is 0.8
At that time, the value is 0.25.

Next, the Auger electron spectroscopic intensity ratio O / C in the film
The oxygen partial pressure of the sputtering gas was adjusted so that o was about 0.1, and the same experiment as above was performed. In FIG. 25, P
The relationship between [Xe + O] / P [t] and the magnetic properties of the film, that is, the perpendicular coercive force, the in-plane coercive force, the saturation magnetization amount Is, and the squareness ratios S and S ^* are shown. In FIG. 26, P [Xe + O] /
The relationship between P [t] and the perpendicular magnetic anisotropy energy (Kp = Ku ^exp + Is ² / 2u ₀ ) measured by a magnetic torque meter is shown. From these figures, it can be seen that the magnetic characteristics change depending on the sputtering gas composition even when the oxygen concentration in the film is almost the same. For example, P [Xe + O] / P
When [t] is less than 0.2, the perpendicular coercive force is small, but when it is 0.2 or more, the perpendicular coercive force increases. Also,
When P [Xe + O] / P [t] is 0.6 or more, the inner surface coercive force increases.

With respect to the film of this example, the oxygen concentration of each minute region was examined by EDX using an analytical electron microscope so that the surface was divided into minute regions of a grid size of several nm. The concentration distribution was examined. Except for the film formed by using only the Xe / oxygen mixed gas or only the Ar / oxygen mixed gas as the sputtering gas, the other films had two peaks in the oxygen concentration distribution on the surface. The degree of separation of the two peaks in the oxygen concentration distribution is P [Xe +
It was more remarkable as O] / P [t] was closer to 0.5.

In a film formed by using only Xe / oxygen mixed gas or only Ar / oxygen mixed gas as a sputtering gas, the oxygen concentration distribution on the surface has only one peak, and oxygen is dispersed almost uniformly. You can see that

The above results are the same when He, Ne or Kr is used instead of Xe or Ar. When reflection X-ray diffraction was measured for the film of this example having an oxygen concentration distribution having two peaks, peak separation was observed corresponding to the oxygen concentration peak.

Similar to the case of the eighth embodiment, the soft magnetic film, the non-magnetic film and the perpendicular magnetization film of the present embodiment are laminated on the substrate,
A perpendicular magnetic recording medium was produced. Furthermore, this medium is shown in FIG.
A device combined with the head shown in FIG. Then, when the recording / reproducing characteristics were evaluated by contact recording, the linear recording resolution was higher than that using a conventional medium,
The result is that the noise is also small. Other experiments conducted in the same manner as in Example 8 also gave the same results as in Example 8.

Next, the relationship between the oxygen concentration in the film and the magnetic characteristics of the film was examined in more detail by EDX decomposition. These results are shown in FIGS. 27 and 28. FIG. 27 shows the relationship between the oxygen concentration at the grain boundaries and the coercive force. FIG. 28 shows the relationship between the oxygen concentration in the grains, the coercive force, and the half-width of the C-axis.

As is clear from FIG. 27, when the oxygen concentration at the grain boundary is less than 15 at%, the maximum coercive force is 30 K.
Only A / m. Further, as is clear from FIG. 28, when the oxygen concentration in the grains exceeded 15 at%, the crystal orientation was significantly reduced, and the perpendicular magnetic anisotropy tended to be reduced. On the other hand, when the oxygen concentration in the grain is less than 1 at%, the stacking fault is small and the coercive force is small in the region within one grain. Therefore, it is desirable that the oxygen concentration is 15 at% or more at the grain boundary and 1 to 15 at% in the grain. Although the CoPt film was used in this example, similar effects were obtained with other Co alloys such as CoNi and CoCr. Further, in this embodiment, a CoPt binary alloy is used, but Pd and N having large magnetic anisotropy are not limited to Pt as long as oxygen is mainly bonded to Co.
An alloy containing i, Cr, Sm, etc. in a range of 40 at% or less may be used. Further, in order to make the crystal grain size finer, Mo, W, Fe, Ti, Cr, Nb,
At least one element selected from the group consisting of Zr and Hf may be added in the range of 20 at% or less. In addition,
From the viewpoint of magnetic anisotropy, the addition amount of these elements is 10
It is preferably at% or less. Further, at least one element selected from the group consisting of Si, V, C, B, and P is used for the purpose of changing the ratio of Co bound to oxygen to oxygen bound to all metal elements. 10a
You may add in the range of t% or less. From the viewpoint of corrosion resistance, the added amount of these elements is preferably 5 at% or less.

Example 12 A glass subjected to a chemical strengthening treatment was used as a substrate, and a soft magnetic film and a nonmagnetic film made of a PtPd alloy were sequentially formed on the glass. Next, a CoPt film was formed by the DC magnetron sputtering method as follows. A Co 20% Pt alloy having a diameter of 5 inches was used as a target, and the distance between the substrate and the target was set to 120 mm, and the target was set in a DC magnetron sputtering apparatus. The substrate temperature was set to 5 ° C. or lower by cooling the back side of the substrate holder with liquid nitrogen, the total sputtering pressure was set to 4 Pa, and the sputtering power was set to 1 kW per 5 inch diameter to form a CoPt film. At this time, as the sputtering gas, 0.01% oxygen-containing Xe gas,
Two kinds of Ar gas containing 0.01% oxygen were used, and the ratio of both was set to 1: 1.

Oxygen mixed in the film is converted into XPS (X-ray).
photoelectron spectroscopy
Oxy), the oxygen concentration was 30 at%. Of these, the proportion of oxygen adsorbed and bound is 60
%, The proportion of oxygen bound to the metal element was 20%, and the proportion of oxygen bound to form a hydrogen group was 20%. This film was heat-treated in a temperature range of 500 to 300 ° C. for 1 to 120 minutes in vacuum to prepare a film in which the ratio of adsorbed and bonded oxygen to the total oxygen amount was different depending on the heating temperature and the heating time. In this case, when the substrate temperature was low, the total oxygen content tended to decrease. On the other hand, when the substrate temperature was high, the total oxygen amount did not decrease, and only the adsorbed oxygen amount tended to decrease.

These films were subjected to a sliding test with a pin-on-disk using a sapphire pin, and the number of slidings until scratches or cracks were generated was examined.
FIG. 29 shows the relationship between the concentration of adsorbed oxygen and the number of slides. In addition, the number of sliding times in FIG. 29 is shown by standardizing the value of the most successful one as 1.0. from this result,
I found the following. That is, the hardness of the film is insufficient in the film having the adsorbed oxygen amount of less than 1 at%,
The surface of the film was dented and scratched. On the other hand, the amount of adsorbed oxygen is 15
When it exceeds at%, although the film hardness is sufficient, the internal compressive force of the film is strong and cracks easily occur. Adsorbed oxygen amount is 1
The film with ˜15 at% showed good sliding properties.

As a result of performing EDX analysis on these films, the oxygen concentration peak was separated into two peaks. In addition, regarding these films, EELS (electronene)
As a result of performing the rgy-loss spectroscopy analysis, in the film in which the oxygen in the grain is mainly adsorbed and bound and the oxygen in the grain boundary is bound to Co, the perpendicular magnetic anisotropy energy and the sliding property are particularly used. It turned out to be excellent. The same results as above were obtained when nitrogen was contained in addition to oxygen.

[0144]

As described above in detail, according to the present invention, it is possible to provide a magnetic thin film for a magnetic recording medium which has a large saturation magnetization amount, a perpendicular magnetic anisotropy, a coercive force, and a small magnetic dispersion. Further, according to the magnetic recording / reproducing apparatus of the present invention, since the magnetic thin film of the magnetic recording medium contains the chemical phase, the electric resistance of the medium becomes high, and the perpendicularly recorded state becomes a magnetoresistive effect type. It becomes possible to read by the reproducing head. Further, since the magnetic thin film of the magnetic recording medium contains the chemical phase, the mechanical strength of the medium is increased, and the protective film to be formed on the surface of the medium can be eliminated or thinned. Can be reduced to improve the cotton density.

[Brief description of drawings]

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

FIG. 2 is a sectional view of a perpendicular magnetic recording medium according to the present invention.

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

FIG. 4 is a sectional view of a perpendicular magnetic recording medium according to the present invention.

FIG. 5 is a sectional view of a perpendicular magnetic recording medium according to the present invention.

FIG. 6 is a configuration diagram showing a recording / reproducing head according to the present invention.

FIG. 7 is a configuration diagram showing a recording / reproducing head according to the present invention.

FIG. 8 is a configuration diagram showing a recording / reproducing head according to the present invention.

FIG. 9 is a configuration diagram showing a recording / reproducing head according to the present invention.

FIG. 10 is a configuration diagram showing a recording / reproducing head according to the present invention.

FIG. 11: Co produced in Example 1 of the present invention
The X-ray diffraction diagram after heat processing of a Pt magnetic thin film.

FIG. 12: Co produced in Example 1 of the present invention
Rocking curve of CoO crystal grains after heat treatment of Pt magnetic thin film.

FIG. 13: Co produced in Example 1 of the present invention
The figure which shows the IH loop after heat processing of a Pt magnetic thin film.

FIG. 14: Co produced in Example 3 of the present invention
The figure which shows the IH loop after heat processing of a Pt magnetic thin film.

FIG. 15: Co produced in Example 8 of the present invention
For the Pt magnetic thin film, the ratio of the sputtering time by Ar / oxygen mixed gas to the total sputtering time T [Ar + O] /
The figure which shows the relationship between T [t], the perpendicular coercive force of a film | membrane, the in-plane coercive force, the saturation magnetization amount Is, and the squareness ratios S and S ^* .

FIG. 16: Co produced in Example 8 of the present invention
For the Pt magnetic thin film, T [Ar + O] / T [t]
The relationship with the perpendicular magnetic anisotropy energy is shown.

FIG. 17: Co produced in Example 8 of the present invention
The figure which shows the oxygen concentration distribution of the surface about a Pt magnetic thin film.

FIG. 18 is a diagram showing the oxygen concentration distribution on the surface of a CoPt magnetic thin film produced using only an Ar / oxygen mixed gas as a sputtering gas.

FIG. 19: Co produced in Example 9 of the present invention
For the Pt magnetic thin film, the ratio of the time when the sputtering pressure was 10 Pa to the total sputtering time T [10 Pa] / T
[T], perpendicular coercive force of the film, in-plane coercive force, saturation magnetization I
The figure which shows the relationship with s and squares S and S ^* .

FIG. 20: Co produced in Example 9 of the present invention
For the Pt magnetic thin film, T [10 Pa] / T [t]
The figure which shows the relationship with perpendicular magnetic anisotropy energy.

FIG. 21: C prepared in Example 10 of the present invention
Regarding the oPt magnetic thin film, no. No. 2 of sputtering power for the target of No. 2 Ratio W [2] / W [1] to sputtering power (3.0 kW) for 1 target
FIG. 7 is a diagram showing the relationship among the perpendicular coercive force of the film, the in-plane coercive force, the saturation magnetization amount Is, and the squareness ratios S and S ^* .

FIG. 22 C prepared in Example 11 of the present invention
Regarding the oPt magnetic thin film, the ratio P [Xe + O] / P [t] of the pressure of the Xe / oxygen mixed gas to the total pressure, the perpendicular coercive force of the film, the in-plane coercive force, the saturation magnetization Is, and the squareness ratio S, S. ^The figure which shows the relationship with ^* .

FIG. 23: C prepared in Example 11 of the present invention
For the oPt magnetic thin film, P [Xe + O] / P [t]
FIG. 6 is a diagram showing the relationship between the magnetic field and the perpendicular magnetic anisotropy energy.

FIG. 24: C prepared in Example 11 of the present invention
For the oPt magnetic thin film, P [Xe + O] / P [t]
FIG. 6 is a diagram showing the relationship between the Auger electron spectroscopic intensity ratio O / Co of oxygen and Co atoms by AES analysis.

FIG. 25 shows O / C in the film in Example 11 of the present invention.
For a CoPt magnetic thin film produced under the condition that o is substantially constant, P [Xe + O] / P [t], the perpendicular coercive force of the film, the in-plane coercive force, the saturation magnetization amount Is, and the squareness ratio S, The figure which shows the relationship with S ^* .

FIG. 26 shows O / C in the film in Example 11 of the present invention.
The figure which shows the relationship between P [Xe + O] / P [t] and perpendicular magnetic anisotropy energy about the CoPt magnetic thin film produced on condition that o became substantially constant.

FIG. 27 C prepared in Example 11 of the present invention
The figure which shows the relationship between oxygen concentration in a grain boundary, and coercive force about an oPt magnetic thin film.

FIG. 28: C prepared in Example 11 of the present invention
The figure which shows the relationship between the oxygen concentration in a grain, coercive force, and the half-value width of a C-axis about an oPt magnetic thin film.

FIG. 29. C prepared in Example 12 of the present invention
The figure which shows the relationship between the adsorption oxygen concentration and the number of sliding times in a sliding test about an oPt magnetic thin film.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Perpendicular magnetization film, 10 ... Medium, 11 ... Substrate, 12
... Underlayer, 13 ... Non-magnetic film, 14 ... Antiferromagnetic film,
Reference numeral 15 ... Protective film, 100 ... Magnetic head, 101 ... Arm, 102 ... Playback return shake, 103, 1
04 ... Reproducing electrode, 105, 113 ... MR film, 10
6, 110, 119 ... Insulating material, 107, 117 ... Main magnetic pole, 108, 118 ... Recording coil, 109 ... Recording return shake, 111, 115 ... Magnetic shield film, 112, 114, 116 ... Non-magnetic film.

Claims (10)

[Claims] 1. A magnetic recording medium having a CoPt alloy-based perpendicular magnetization film formed on a substrate, wherein the perpendicular magnetization film is CoP.
A perpendicular magnetic recording medium comprising a crystalline phase of a t alloy and a compound phase selected from the group consisting of a Co oxide phase, a nitride phase and a carbide phase. 2. A perpendicular magnetic recording medium having a Co-based perpendicular magnetic film formed on a substrate, wherein the perpendicular magnetic film has two peaks in oxygen concentration distribution on its surface. 3. A magnetic recording medium in which a Co-based perpendicular magnetic film is formed on a substrate, wherein the perpendicular magnetic film contains at least one of adsorbed oxygen and adsorbed nitrogen in an amount of 1 to 15 at.
% Perpendicular magnetic recording medium. 4. A perpendicular magnetic recording medium having an underlayer provided between the substrate and the perpendicular magnetization film of the magnetic recording medium according to claim 1. 5. A perpendicular magnetic recording medium comprising an underlayer non-magnetic film provided between the substrate and the perpendicular magnetic film of the magnetic recording medium according to claim 1. 6. A perpendicular magnetic recording medium, wherein the underlayer according to claim 5 has a laminated structure of a soft magnetic film and an antiferromagnetic film. 7. A perpendicular magnetic recording medium in which a Co-based perpendicular magnetization film is formed on a substrate, wherein a laminated structure underlayer of a soft magnetic film and an antiferromagnetic film is provided between the substrate and the perpendicular magnetization film. A perpendicular magnetic recording medium characterized by the above. 8. A magnetic recording medium in which a CoPt alloy-based magnetic thin film provided on a substrate contains a CoPt alloy crystal phase and a compound phase selected from the group consisting of a Co oxide phase, a nitride phase and a carbide phase. A magnetic recording / reproducing apparatus characterized in that the magnetic recording medium is magnetized in the perpendicular direction by a magnetic head for recording, and the recorded state is read by a magnetoresistive reproducing head. 9. A Co-based magnetic thin film provided on a substrate,
A magnetic recording medium having two peaks in the oxygen concentration distribution on its surface, in which this magnetic recording medium is perpendicularly magnetized and recorded, and the recorded state is recorded by a magnetic low-diffusion effect reproducing head. A magnetic recording / reproducing apparatus characterized by reading. 10. The magnetic recording / reproducing apparatus according to claim 5, wherein the reproducing head is a yoke type MR head, and the recorded state is read by contacting the magnetic recording medium.