JP3415884B2 - Magnetic recording media - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording medium,
In particular, the present invention relates to a magnetic recording medium in which the crystallographic orientation of crystal grains of a magnetic film is improved to be suitable for high density magnetic recording, and a method for manufacturing the same.

[0002]

[Outer 1]

[0003]

2. Description of the Related Art In order to realize high-density magnetic recording, research and development using a continuous magnetic film for a magnetic recording medium have been advanced. These magnetic recording media are polymer films, NiP
A thin film made of ferromagnetic metal Co or Co alloy is formed on a substrate made of a non-magnetic material such as aluminum or glass coated with a film by a high frequency sputtering method, an ion beam sputtering method, a vacuum deposition method, an electroplating method, or a chemical method. It is formed by a plating method or the like. In the magnetic recording medium thus manufactured, there is a close relationship between the fine structure of the magnetic film and the magnetic characteristics, and various attempts have been made to improve the magnetic film in order to increase the recording density and reproduction output of magnetic recording. Has been.

In order to improve the fine structure of the magnetic film having in-plane magnetic anisotropy and improve the recording / reproducing characteristics, a method of providing an underlayer between the substrate and the magnetic film has been studied.
In Japanese Unexamined Patent Publication No. 62-257617, a W, Mo, Nb or V film is used as an underlayer of a Co-Pt magnetic film, and in Japanese Unexamined Patent Publication No. 62-257618, V-Cr is used as an underlayer. Alternatively, it is described that an Fe-Cr alloy material is used, and in JP-A-63-106917, Co, N is used.
i, Cr and Pt are used as an underlayer of a magnetic film, Cr,
A method for forming a film of a non-magnetic material such as Ho, Ti, Ta is disclosed in Japanese Patent Laid-Open No. 63-187414, Co-Pt-.
It is described that Cr or a Cr-V alloy is effective as the underlayer of the Cr magnetic film.

When a Cr or Cr alloy is formed as a base layer on the substrate by a sputtering method or the like, a (100) or (110) oriented film is obtained, and when a Co alloy magnetic film is formed on the (100) oriented film, an easy axis of magnetization is formed. Becomes parallel to the substrate, while (1
10) When formed on the orientation film, the easy axis of magnetization is approximately 30 degrees from the surface of the substrate, but is substantially parallel to the substrate, and it is known to be desirable as an in-plane magnetic recording medium.

[0006]

As an in-plane magnetic recording medium capable of high density magnetic recording and high reproduction output, in addition to the large coercive force (Hc) and saturation magnetization (Ms) of the magnetic film, It is necessary that the magnetic susceptibility (Mr / Ms) is large and the dispersion of magnetic anisotropy is small. The above-mentioned known technique can form a magnetic recording medium having a large Hc and Ms to some extent, but is insufficient to form a medium having a large residual magnetic susceptibility and a small dispersion of magnetic anisotropy. .

The dispersion of the residual magnetic susceptibility and the magnetic anisotropy is correlated with the grain size distribution of the crystal grains forming the magnetic thin film and the distribution of the easy axis of magnetization, and realizes a large residual magnetic susceptibility and a small dispersion of the magnetic anisotropy. For this purpose, it is necessary that the crystal grain sizes are uniform and the easy axes of magnetization of the crystal grains are substantially aligned in the in-plane direction. More preferably, the axis of easy magnetization should be aligned with the running direction of the magnetic head used for recording and reproduction.

The present invention provides an in-plane magnetic recording medium suitable for high-density magnetic recording, in which the easy axis of magnetization of the magnetic film faces in-plane and the dispersion of magnetic anisotropy is small, and a method for manufacturing the same. To aim.

[0009]

As a result of experiments conducted by the present inventors, it was revealed that the above object can be achieved by the following method. That is, NaC as a substrate or a base layer
(110) single crystal or (11) with l-type crystal structure
0) An alignment film is used, and a body-centered cubic structure (bcc) is formed on the alignment film.
By forming the underlayer material having a single crystal or orientation film having a (211) plane orientation parallel to the substrate. When a Co-based alloy magnetic film having a hexagonal close-packed structure (hcp) is formed on this film, a single crystal film or an orientation film whose (1-100) plane is parallel to the substrate is obtained as the magnetic film. In this case, the [0001] axis, which is the easy axis of magnetization of the magnetic film, is parallel to the substrate.

Further, it has a NaCl type crystal structure (11
0) hcp directly on single crystal or (110) oriented film
Even if a Co-based alloy magnetic film having a structure is formed, the [0001] axis, which is the easy axis of magnetization of the magnetic film, is parallel to the substrate. b
When the film having the cc structure is used, the crystal grain size and the distance between the crystal grains can be adjusted while maintaining the (211) orientation by controlling the film forming conditions, and thus the fine structure of the magnetic recording medium can be adjusted. Therefore, the magnetic recording medium may be used depending on the purpose of use.

As a method of forming a (110) oriented film of a material having an NaCl structure on a base substrate, for example, a fine undulation called a grating or a texture is formed on the substrate, and graphoepitaxial growth is used on this. Then, it is possible to grow a (110) orientation film. Regarding the graphoepitaxial growth technique, for example, “Solid State Physics” Vol. 20, No. 10 (198)
5), pages 815-820. If the grating or texture is formed in the circumferential direction of the disk-shaped substrate, the easy axis of magnetization of the Co-based alloy magnetic film can be aligned in the circumferential direction.

When the above method is used, the easy axis of magnetization of the magnetic film can be controlled in parallel with the substrate, and the easy axis of magnetization can be aligned in the circumferential direction on a disk-shaped substrate. The running direction of the magnetic head can be made the same, and as a result, the performance of the in-plane magnetic recording medium is improved. Since the distribution of crystal grains in the magnetic film can be controlled, it is possible to provide a recording medium suitable for high density magnetic recording.

Further, when a magnetic recording medium is used in combination with a magnetic head, in consideration of realizing a high track density, the magnetic recording medium manufactured by the above method is provided with a groove or a dent, a nonmagnetic region or an optical region. Areas having different reflectances may be provided. As a material having a NaCl type crystal structure,
MgO, CaO, TiO, VO, MnO, CoO, Ni
Any one of O or a mixed crystal containing these as a main component, any one of LiCl, NaCl and KCl or a mixed crystal containing any of these as a main component, LiF, or TiC, Z
Any of rC, HfC, NbC, and TaC or a mixed crystal containing these as the main components is suitable. The film thickness is preferably 10 nm or more and 100 μm or less. When the thickness is 10 nm or less, it becomes difficult to block the influence of the base substrate on the growth of the film having the bcc structure, and when it is 100 μm or more, the time required for the film formation becomes long, and the crystal grains of the alignment film become coarser, which is not desirable. A phenomenon occurs.

As the film having the bcc structure, Cr, V,
Nb, Mo or an alloy containing these elements as the main components can be used. The film thickness is preferably 1 μm or less, and more preferably 200 nm or less economically and practically considering that the film is formed by a film forming method such as a sputtering method. hc
The Co-based alloy magnetic film having a p-structure is based on Co, and contains Cr, Ni, Fe, V, Ti, Zr, Hf, and M.
o, W, Ta, Re, Ru, Rh, Ir, Pt, Pd,
An alloy film containing at least one element of Au, Ag, Cu, B, Al, C, Si, P and N can be used. For example, Co-Cr, Co-Ni, Co-Fe, Co-V,
Co-Mo, Co-Ta, Co-Re, Co-Pt, C
Binary alloys such as o-Pd, or Co-Cr-Ta and Co-Cr-P obtained by adding a third element to these binary alloys.
t, Co-Cr-Mo, Co-Cr-W, Co-Cr-
Re, Co-Ni-Zr, Co-Pt-Ta, Co-P
ternary alloys such as t-B, or Co-C added with a fourth element
r-Ta-B, Co-Cr-Ta-Si, Co-Cr-
Ta-C, Co-Cr-Ta-P, Co-Cr-Ta-
N, Co-Cr-Pt-B and the like. If the ratio of Co is maximum and the crystal structure is hcp, the Co-based alloy magnetic film of the present invention can be obtained. Further, the magnetic film is not limited to a single layer, but can be a multilayer film or a film having a composition gradient in the film thickness direction. The film thickness is 2 nm or more and 100 nm
Hereafter, it is preferably 5 nm or more and 50 nm or less.

As a film forming method, a high frequency sputtering method, a high frequency magnetron sputtering method, an ion beam sputtering method,
Physical vapor deposition methods such as an ion beam plating method and a vacuum vapor deposition method can be used.

[0016]

1 is a sectional perspective view of a part of a disk-shaped magnetic disk according to an embodiment of the present invention. A description will be given with reference to this figure. For example, a grating or texture 102 having an apex angle θ of about 90 degrees is provided on the surface of a non-magnetic substrate 101 having an outer shape, and a surface having a NaCl-type crystal structure is formed by grapho-epitaxial growth on the surface. An alignment film 103 having 110) is obtained.

It is effective to align the grating or texture with the circumferential direction of the disk. in this case,
The grating or texture does not necessarily need to be continuous all around, and may be intermittent. NaCl
A material having a type crystal structure tends to develop the {100} plane, and if the apex angle is approximately 90 degrees as shown in Fig. 1, the {100} plane will grow parallel to the slope. ,
As a result, the surface of the film parallel to the base substrate becomes the (110) plane. Even if the apex angle is deviated by about 30 degrees around 90 degrees, Na having a (110) plane parallel to the base substrate is used.
A Cl orientation film is obtained. A film having a NaCl-type crystal structure in which the (110) plane is preferentially oriented can be obtained even if there is an error of several tens% in the depth of each undulation with respect to the average depth. When it is desired to make the surface of this film flat, it is desirable to carry out polishing after graphoepitaxial growth.

The [001] direction of each crystal grain of the alignment film having the NaCl type crystal structure is substantially parallel to the direction of the grating or the texture stripe, that is, the circumferential direction of the disk-shaped substrate. When a film having a bcc structure is formed on this film, it becomes (21
1) The alignment film 104 whose surface is parallel to the base substrate is grown.
Next, when a Co-based alloy magnetic film having an hcp structure is formed, an alignment film 105 whose (1-100) plane is parallel to the base substrate grows due to an epitaxial phenomenon. The easy axis of magnetization [0001] of the magnetic film is parallel to the substrate, and is almost parallel to the direction of the grating or texture stripes.
That is, it is parallel to the circumferential direction of the disk-shaped substrate. A magnetic recording medium is obtained by forming the protective film 106 on this.

The depth of the grating or texture is related to the size of individual crystal grains of the oriented film having a NaCl type crystal structure formed thereon, and the smaller the depth, the smaller the film forming conditions under the same conditions. Crystal grains are formed.
The desirable size range of the crystal grains of the material having the hcp structure forming the magnetic film is 2 nm or more and 100 nm or less. In order to form such a magnetic film, the depth of the grating or texture should be 1 nm or more and 200 nm.
The following is desirable. The average pitch of the texture peaks is also 1 nm or more in the radial direction of the disk-shaped substrate.
It is preferably 0 nm or less. If the pitch is 1 nm or less, grapho-epitaxial growth becomes difficult to occur, and if it is 500 nm or more, the easy axis of magnetization of the magnetic film is difficult to align in the circumferential direction of the disk.

FIG. 2 shows a magnetic recording having a structure in which a material film having a bcc structure is omitted and a Co-based alloy magnetic film having an hcp structure is directly formed on a film having a (110) oriented NaCl type crystal structure. It is a cross-sectional structure schematic diagram of a medium. In this case as well, the easy axis of magnetization of the magnetic film is parallel to the substrate, and an effect similar to the above occurs. FIG. 3 shows a case where a discrete grating or texture is provided on the surface of the non-magnetic substrate 301, and the material film having a bcc crystal structure formed directly on the undulations has a (211) orientation and Co having an hcp crystal structure. The base alloy magnetic film exhibits a (1-100) orientation. Furthermore, the easy axis of magnetization of the magnetic film formed directly on the undulations is along the direction of the texture or grating, and the distribution of crystal grains on the substrate is also along that direction.
When performing magnetic recording, a desired effect similar to the above case is produced. In this case, the distance between the undulations is a fraction of the magnetic recording width defined by the track width of the magnetic head.
It is necessary to set it below, and in order to achieve a magnetic recording density of 1 Gb / in ² or more, it is desirable to set it to 100 nm or less.

FIG. 4 shows a structure in which the material film having the bcc structure in FIG. 3 is omitted and the Co-based alloy magnetic film having the hcp structure is directly formed on the film having the (110) -oriented NaCl type crystal structure. FIG. 3 is a schematic sectional view of a magnetic recording medium of Also in this case, the easy axis of magnetization of the magnetic film formed directly on the undulations is parallel to the substrate, and the same effect as in the case of FIG. 3 is produced.

FIG. 5 shows Na having a (110) plane as a substrate surface.
This is a case where a single crystal substrate of a material having a Cl type crystal structure is used. Since the (211) plane is epitaxially grown on the bcc structure film and the (1-100) plane is epitaxially grown on the hcp structure film, the easy axis of magnetization is parallel to the substrate.
Since there is usually a mismatch in the lattice constant between the substrate and the material having the bcc crystal structure, subgrain boundaries are formed in the material film having the bcc and hcp crystal structures in order to mitigate the mismatch. By adjusting the film forming conditions, such as the substrate temperature and the film forming rate, the size of the crystal grains divided at the sub-grain boundaries can be controlled to 5 to 100 nm which is desirable for magnetic recording.

In FIG. 6, the material film having the bcc structure is omitted in FIG. 5, and the Co having the hcp structure is directly formed on the single crystal substrate having the NaCl type crystal structure having the (110) plane.
FIG. 3 is a schematic cross-sectional structure diagram of a magnetic recording medium having a structure in which a base alloy magnetic film is formed. Also in this case, the easy axis of magnetization of the magnetic film is parallel to the substrate, and an effect similar to the case of FIG. 3 is produced.

The magnetic recording medium using the single crystal substrate shown in FIGS. 5 and 6 can be used for magnetic recording as a disk-shaped magnetic disk. In this case, the direction of the easy axis of magnetization in the magnetic recording medium with respect to the magnetic head changes depending on the direction of the disk, and, for example, the reproduction output changes. However, this change is a change that occurs periodically with respect to the crystal orientation of the disk, and can be corrected during recording and reproduction. Further, by combining a magnetic recording medium formed on a rectangular single crystal substrate with a magnetic head that makes a single oscillatory motion on the substrate, it can be used as a new magnetic recording system. By moving the magnetic recording medium in a direction orthogonal to the movement of the magnetic head, recording and reproduction can be performed on the rectangular magnetic recording medium.

[0025]

EXAMPLES The present invention will be described in detail below with reference to examples. Example 1 A quartz glass substrate 101 having a diameter of 1.8 inches
Using a diamond terminal with a tip angle of 90 degrees on the surface of
A concentric circular grating 102 having a depth of 50 nm and a pitch of 100 nm was formed. Using this substrate, a magnetic recording medium having the structure shown in FIG. 1 was manufactured by the following procedure.

The substrate 101 is kept at a high temperature by the high frequency sputtering method, and the LiF film 103 having a NaCl structure is formed to 100 n.
It was formed to a thickness of m. After forming the film, heat treatment was performed in an electric furnace kept in an inert gas atmosphere. As a result of examining the LiF film by the X-ray diffraction method, the LiF film was an oriented polycrystalline film in which the (110) plane was substantially parallel to the substrate, and the crystal grain [00]
It was found that the [1] directions were distributed in almost concentric circles. When the fine structure of the LiF film was examined by a scanning electron microscope, it was confirmed that the LiF film was composed of crystal grains having a particle diameter of 50 to 100 nm and that undulations of 30 to 100 nm were present on the surface.

Then, after the surface is polished and flattened, a high-frequency magnetron sputtering method is used to form a Cr film 104 having a bcc crystal structure and having a thickness of 50 nm and an hc having a thickness of 30 nm.
A Co-Cr-Pt film 105 having a p crystal structure was formed. Co-18 at% Cr-6 at% Pt for magnetic film
A target was used. Substrate temperature during formation of Cr film is 400
The substrate temperature at the time of forming the magnetic film is 18 ° C.
It was set to 0 ° C. Ar gas pressure for sputtering is 3-10 mT
The orr and the sputter power were set to 6 to 10 W / cm ² .
Further, a carbon film having a thickness of 10 nm was formed as the protective film 106 to manufacture a magnetic recording medium. The film structure was examined by X-ray diffraction, and the Cr film had a (211) orientation and Co-Cr-P
It was confirmed that the t film was a polycrystalline film having a (1-100) orientation.

Under the same conditions as above, instead of Cr, V,
Nb, Mo, Cr-5 at% Ti, Cr-2 at% Z
A magnetic recording medium using r, Cr-20 at% V, Cr-1 at% B was produced. Base film with bcc structure, hc
It was confirmed by an X-ray diffraction method that a structure similar to the above was realized in the magnetic film having the p structure. As a comparative sample, a magnetic recording medium was prepared in which a Cr film, a Co—Cr—Pt magnetic film, and a C protective film were directly formed on a silica glass substrate without forming a grating under the same conditions as above. As a result of X-ray diffraction analysis, the Cr film was (100) and (11).
0) shows a mixed orientation, and the easy axis of magnetization of the magnetic film is parallel to the substrate and the easy axis of magnetization is about 30 from the substrate.
It was found that the crystal grains that were tilted were mixed and the direction of the easy axis was irregularly distributed in the plane of the substrate.

The recording / reproducing characteristics of these magnetic recording media were evaluated using a thin film magnetic head. The magnetic head track width was 5 μm, the gap length was 0.2 μm, the distance between the magnetic head and the magnetic recording medium at the time of measurement was 0.06 μm, and the relative speed was 10 m / s. As evaluation items, recording density characteristics, signal-to-noise ratio (S / N ratio), and off-track characteristics were selected. The recording density characteristic is an output half recording density (D ₅₀ ) that is half of the reproduction output at low frequency, the S / N ratio is a relative value based on the S / N ratio of the comparative sample, and the off-track characteristic is recording at the track edge portion. The bleed distance was measured as a relative value compared to the comparative sample. The larger the S / N ratio,
The smaller the off-track characteristic, the more suitable it is for high-density magnetic recording.

[0030]

[Table 1]

The magnetic recording medium of this example has improved recording density characteristics, S / N ratio and off-track characteristics as compared with the comparative example, and it is confirmed that the magnetic recording medium has desirable characteristics as a high density magnetic recording medium. It was Further, as a material having a NaCl-type crystal structure, LiCl or NaC is used instead of LiF.
1, KCl, MgO, CaO, TiO, VO, MnO,
CoO, NiO, TiC, ZrC, HfC, NbC, T
An experiment using a (110) orientation film made of any material of aC was also conducted. Different materials change the conditions of graphoepitaxy growth, and it is necessary to select a film forming method suitable for the material, a substrate temperature during film formation, a heat treatment after film formation, or the like. ) It was found that even when the preferential orientation film is used, it has desirable characteristics as a high density magnetic recording medium as described above.

Reference Example 1 A concentric grating 202 having a depth of 50 nm and a pitch of 100 nm was formed by the same procedure as in Example 1 except that the film formation of the material having the bcc crystal structure was omitted. A (110) oriented film 203 having a NaCl structure, an oriented magnetic film 204 having an hcp structure, and a protective film 205 are sequentially formed on the surface of an 8-inch quartz glass substrate 201 to manufacture a magnetic recording medium having the structure shown in FIG. did.

As the magnetic film 204, Co-18 at%
Cr, Co-12 at% Ni, Co-18 at% Fe,
Co-20 at% V, Co-20 at Mo, Co-16
at% Ta, Co-20 at% Re, Co-16 at%
Pt, Co-15 at% Pd binary alloy, Co-
18 at% Cr-2 at% Ta, Co-21 at% Cr
-3 at% Mo, Co-19 at% Cr-1.5 at%
W, Co-15 at% Cr-7 at% Re, Co-14
at% Ni-1 at% Zr, Co-16 at% Pt-2
ternary alloy consisting of at% Ta, Co-18 at% Pt-0.8 at% B, Co-18 at% Cr-2 at% Ta
-2 at% B, Co-20 at% Cr-1.5 at% T
a-0.3 at% Si, Co-19 at% Cr-2.5
at% Ta-0.8 at% C, Co-22 at% Cr-
1.6 at% Ta-0.2 at% P, Co-21 at%
Cr-1 at% Ta-0.2 at% N, Co-12 at
A quaternary alloy composed of% Cr-8 at% Pt-0.7 at% B was used.

As comparative samples, magnetic recording media were prepared in which a 50 nm thick Cr film was formed as a base film on a flat quartz glass substrate, the above magnetic film was formed thereon, and then a C protective film was formed. Among the recording / reproducing characteristics of the magnetic recording medium obtained by using the (110) oriented film of NiO as the material having the NaCl crystal structure, the linear recording density (D ₅₀ : kFC
I) was as follows.

[0035]

[Table 2]

Also in the S / N ratio and the off-track characteristics other than the linear recording density, the magnetic recording medium according to the present reference example is compared with a comparative sample having a magnetic film of the same composition formed using a conventional Cr underlayer. An improvement of 10% or more was confirmed, and it was found to be excellent as a high density magnetic recording medium. Also,
The same improvement effect was observed when the magnetic film was formed on the (110) oriented film having a NaCl crystal structure other than NiO.

Example 2 A glass substrate 301 having a diameter of 1.8 inches has a tip angle of 9 on the surface thereof.
Groove 30 with a depth of 20 nm using a 0 degree diamond terminal
2 were formed concentrically with a pitch of 75 nm. Using this substrate, a magnetic recording medium having the structure shown in FIG. 3 was manufactured by the following procedure.

NaC is formed on the substrate 301 by the high frequency sputtering method.
A KCl film 303 having an l structure was formed to a thickness of 50 nm. After forming the film, heat treatment was performed in an electric furnace maintained in a gas atmosphere containing water vapor. As a result of investigating the KCl film by the X-ray diffraction method, the KCl film is an oriented polycrystalline film in which two kinds of planes, the (110) plane and the (100) plane, are substantially parallel to the substrate.
It was confirmed by line diffraction that the intensity of the (110) plane was strong and that it was a preferential alignment film of the (110) plane. Furthermore, the crystal grains are
It was found that they were distributed almost concentrically. When the fine structure of the KCl film was examined by a scanning electron microscope, it was confirmed that the KCl film was composed of crystal grains having a particle diameter of 30 to 100 nm and that undulations of 20 to 50 nm were present on the surface.

After the surface is polished and flattened, a Cr-2 at% Zr film 304 having a thickness of 50 nm having a bcc crystal structure and a Co-Cr-Ta film having a thickness of 20 nm having an hcp crystal structure are formed by a high frequency magnetron sputtering method. The film 305 was formed. Co-18 at% Cr-3 at for magnetic film
% Ta target was used. The substrate temperature during formation of the Cr-Zr film was 300 ° C, and the substrate temperature during formation of the Co-Cr-Ta magnetic film was 150 ° C. Ar gas pressure for sputtering is 3 to 10 mTorr, sputtering power is 6 to 10 W / c
It was set to m ² . Further, a carbon film having a thickness of 10 nm was formed as the protective film 306 to manufacture a magnetic recording medium. X
The film structure was examined by line diffraction, and the (200) diffraction was slightly observed in the Cr-Zr film, but the intensity of the (211) diffraction line was strong,
It was confirmed to be a (211) preferential alignment film. Co-C
It was confirmed that the r-Ta film was a polycrystalline film having a (1-100) preferential orientation.

Reference Example 2 In the same manner as in Example 2 , Cr-having a bcc crystal structure was used.
Glass substrate 4 provided with groove 402 without forming a Zr film
01 directly on the KCl film 403 formed on
A -Ta magnetic film 404 was formed, and a C protective film 405 was further provided to manufacture a magnetic recording medium having the structure shown in FIG.

As a comparative sample to Example 2 and Reference Example 2, a Cr-Zr film and a Co- film were directly formed on a flat glass substrate.
A magnetic recording medium having a Cr-Ta film and a C film formed was produced. As a result of comparing the recording / reproducing characteristics under the same conditions as in Example 1, the magnetic recording media according to Example 2 and the reference example 2 provided with the KCl film exhibiting the (110) preferential orientation have linear recording densities. 20%, the S / N ratio was 45%, and the off-track characteristic was 30% or more, which was superior to the comparative sample. The same desirable effect was confirmed when LiCl, NaCl, or LiF was used as another material instead of the KCl film.

Example 3 A magnetic recording medium having a structure shown in FIG. 5 was manufactured by the following procedure using a rectangular (110) MgO single crystal having a side of 20 mm as a substrate 501. A 30 nm thick V film 502 having a bcc crystal structure and a 15 nm thick Co-C film having an hcp crystal structure were formed by a high frequency magnetron sputtering method.
An r-Ta-Si film 503 was formed. Co for magnetic film
A -19 at% Cr-2 at% Ta-2 at% Si target was used. The substrate temperature at the time of V film formation is 450 ° C, C
The substrate temperature during the formation of the o-Cr-Ta-Si magnetic film is 150.
It was set to ° C. Ar gas pressure for sputtering is 3 mTorr,
The sputtering power was 10 W / cm ² . Further, a boron film having a thickness of 10 nm was formed as the protective film 504 to manufacture a magnetic recording medium.

The film structure was examined by X-ray diffraction, and the V film was (21
1) Epitaxially grow the plane parallel to the substrate, Co-C
It was confirmed that the r-Ta-Si film was epitaxially grown with the (1-100) plane parallel to the substrate. When the structure of the magnetic recording medium was examined with a transmission electron microscope, the magnetic film contained sub-grain boundaries, and the crystal grains separated by the sub-grain boundaries had an inclination of 0.3 to 1 degree. The average size of the crystal grains was 45 nm. In addition, when the composition inside the crystal grains was examined, Cr and Si were segregated near the subgrain boundaries.
The easy axis of magnetization of this magnetic recording medium is aligned in one direction, and this direction corresponds to [001] of the (110) MgO substrate.

Reference Example 3 In the same manner as in Example 3 , the C film was directly formed on the (110) MgO substrate 601 without forming the V film having the bcc crystal structure.
An o-Cr-Ta-Si magnetic film 602 is formed, and further C
A magnetic recording medium having the structure shown in FIG. 6 provided with the protective film 603 was manufactured. Also in this magnetic recording medium, the easy magnetization axis was aligned in one direction.

[Embodiment 4 ] As shown in FIG. 7, a rectangular magnetic recording medium 701 manufactured in Embodiment 3 or Reference Example 3 is combined with a multi-head 702 in which a large number of magnetic heads are arranged on a straight line to combine magnetic fields. A recording device was manufactured and the magnetic recording / reproducing characteristics were measured. The multi-head 702 shown in FIG.
High-speed single-oscillation motion is maintained at intervals of μm, and the magnetic recording medium is configured to be able to move at an arbitrary distance at a high speed in a direction perpendicular to the single-oscillation motion. Linear recording density characteristic of the magnetic recording medium measured by this method, a magnetic recording medium having a V film D ₅₀ = 72kFCI, the magnetic recording medium not provided was D ₅₀ = 65kFCI.

Example 5 A concentric grating having a depth of 50 nm and a pitch of 100 nm was formed on a surface of a quartz glass substrate 801 having a diameter of 1.8 inches by using a diamond terminal having a tip angle of 90 degrees.
Using this substrate, a magnetic recording medium having the structure shown in FIG. 8 was manufactured by the following procedure.

The substrate 801 is kept at a high temperature by the high frequency sputtering method and the MgO film 802 having the NaCl structure is formed to 100 nm.
Formed to a thickness of. After forming the film, heat treatment was performed in an electric furnace kept in an inert gas atmosphere. As a result of investigating the MgO film by the X-ray diffraction method, the MgO film is an oriented polycrystalline film in which the (110) plane is substantially parallel to the substrate, and the [00]
It was found that the [1] directions were distributed in almost concentric circles. When the fine structure of the MgO film was examined with a scanning electron microscope, it was found to consist of crystal grains with a particle diameter of 20 to 50 nm.

After polishing and flattening the surface, a 50 nm thick Cr film 803 having a bcc crystal structure and a 15 nm thick Co—Cr—Pt film 804 having an hcp crystal structure are formed by a high frequency magnetron sputtering method. did. A Co-21 at% Cr-6 at% Pt target was used for the magnetic film. Substrate temperature during formation of Cr film is 400 ° C, C
The substrate temperature during formation of the o-Cr-Pt magnetic film was 180 ° C. The Ar gas pressure for sputtering was 10 mTorr and the sputtering power was 10 W / cm ² . On this magnetic recording medium, a concave pattern 8 for magnetic head following
05 was formed by the photolithography method. That is, by a pattern etching method using a photoresist,
The depressions of 1.5 μm × 1.5 μm × 0.1 μm were formed in a zigzag pattern. Then, a carbon film 806 is formed as a protective film.
It was formed to a thickness of 0 nm.

Since the magnetic recording medium according to the present embodiment has improved magnetic recording / reproducing characteristics, the areal recording density can be improved in principle. In addition to this, a series of depressions formed on the medium is monitored for changes in the reflectance of the semiconductor laser light mounted in a part of the magnetic head, or the output of the magnetic head is directly above the depression. Since it is possible to perform high-precision tracking by using the phenomenon that changes when
The recording density in the track direction can be significantly improved, and a wide range of combinations of the linear recording density and the density in the track direction can be selected. As a result, high-density magnetic recording can be performed more easily.

[0050]

According to the present invention, it is possible to provide a magnetic recording medium having improved recording density, S / N ratio at the time of recording / reproducing, and off-track characteristics. This has the effect of making it easier to reduce the size and increase the capacity.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional configuration diagram of a magnetic recording medium according to a first embodiment of the invention.

FIG. 2 is a schematic cross-sectional configuration diagram of a magnetic recording medium according to Reference Example 1 of the present invention.

FIG. 3 is a sectional view of a magnetic recording medium according to a second embodiment of the invention.

FIG. 4 is a sectional view of a magnetic recording medium according to Reference Example 2 of the present invention.

FIG. 5 is a sectional view of a magnetic recording medium according to a third embodiment of the invention.

FIG. 6 is a sectional view of a magnetic recording medium according to Reference Example 3 of the present invention.

FIG. 7 is a configuration diagram of a magnetic recording device according to a fourth embodiment of the invention.

FIG. 8 is a schematic cross-sectional configuration diagram of a magnetic recording medium according to Example 5 of the invention.

[Explanation of symbols]

101, 201, 301, 401, 801 ... Substrate 102, 202 ... Grating 103, 203 ... (110) Alignment film (NaCl structure) 104 ... (211) Alignment film (bcc structure) 105 ... (1-100) Alignment film ( hcp structure) 106,205,306,405,504,603,8
06 ... Protective film 204 ... Alignment film (hcp structure) 302, 402 ... Grooves 303, 403, 802 ... Films having NaCl structure 304, 502, 803 ... Films having bcc structure 305, 404, 503, 602, 804 ... hcp Structured magnetic films 501, 601 ... (110) Single crystal substrate (NaCl structure) 701 ... Magnetic recording medium 702 ... Multi-head 805 ... Recessed pattern

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01F 41/20 H01F 41/20 (72) Inventor Yoshiyuki Hirayama 1-280 Higashikoigakubo, Kokubunji, Tokyo Metropolitan Hitachi Research Laboratory ( 72) Inventor Yoshifumi Matsuda 1-280, Higashi Koigakubo, Kokubunji, Tokyo, Central Research Laboratory, Hitachi, Ltd. (72) Inventor, Mikio Suzuki 1-280, Higashi Koigakubo, Kokubunji, Tokyo (72) Inventor, Central Research Laboratory (72) Yukio Honda 1-280, Higashi Koigakubo, Kokubunji, Tokyo, Central Research Laboratory, Hitachi, Ltd. (56) Reference JP-A-4-184710 (JP, A) JP-A-4-291017 (JP, A) JP-A-5 -128481 (JP, A) JP-A-5-36054 (JP, A) JP-A-6-309647 (JP, A) JP-A-6-25 9743 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 5/64-5/82

Claims (6)

(57) [Claims] 1. A non-magnetic substrate having a base film having a (211) -oriented body-centered cubic structure and a magnetic film containing a Co-based alloy having a hexagonal close-packed structure formed on the base film. Characteristic magnetic recording medium. 2. A (110) oriented film having a NaCl type crystal structure on a non-magnetic substrate, and a base film having a (211) oriented body-centered cubic structure formed on the (110) oriented film, Co having a hexagonal close-packed structure formed on the base film
A magnetic recording medium having a magnetic film containing a base alloy. 3. A (211) -oriented C on a non-magnetic substrate.
An underlayer made of r, V, Nb or Mo or an alloy containing these elements as a main component, and a magnetic film made of a Co-based alloy having a hexagonal close-packed structure formed on the underlayer. Magnetic recording medium. 4. MgO, CaO, Ti on a non-magnetic substrate
Any one of O, VO, MnO, CoO, and NiO, or a mixed crystal containing these as the main components, or LiCl, NaCl,
Any of KCl or a mixed crystal containing these as main components, LiF, or TiC, ZrC, HfC, Nb
A (110) -oriented layer made of any one of C and TaC or a mixed crystal containing these as the main components, and (211) -oriented Cr, V, Nb or Mo formed on the (110) -oriented layer or these. An underlayer made of an alloy whose main component is C and having a hexagonal close-packed structure formed on the underlayer
A magnetic recording medium having a magnetic film made of an o-based alloy. Wherein said magnetic film, magnetization easy axis magnetic recording medium of any one of claims 1-4, characterized in that the orientation was (1-100) oriented parallel to the substrate. 6. The magnetic film contains Co as a main component and C
r, Ni, Fe, V, Ti, Zr, Hf, Mo, W, T
a, Re, Ru, Rh, Ir, Pt, Pd, Au, A
g, Cu, B, Al, C, Si, P, a magnetic recording medium of any one of claims 1-5, characterized in that it comprises at least one element selected from the element group consisting of N.