JP2001189010A - Magnetic recording media - Google Patents

Abstract

(57) [PROBLEMS] To provide an in-plane or perpendicular magnetic recording medium which can improve the adhesion between an underlayer and a magnetic layer and has excellent operation characteristics when a magnetic film having an fct structure is used. provide. SOLUTION: In a magnetic recording medium having a substrate (1), an underlayer (21) formed on the substrate (1), and a magnetic layer (3) formed on the underlayer (21), The formation (21) is a bulk non-deliquescent substance, for example, $ 1
The magnetic layer (3) is composed of a NaCl type crystal having a crystal orientation of 00 ° and having a lattice constant of 3.52 to 4.20 °,
The magnetic metal element is composed of crystal grains having a t structure, and has a magnetic metal element and a noble metal element as main components. The magnetic metal element is at least one selected from the group consisting of Fe, Co, and Ni, and the noble metal element is Pt, Pd, It is at least one selected from the group consisting of Au and Ir.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic recording medium provided with a magnetic film suitable for high-density magnetic recording.

[0002]

2. Description of the Related Art A magnetic recording apparatus (HDD) for recording / reproducing information with the recent increase in processing speed of a computer.
Requires high speed and high density. At present, the in-plane recording method in which the magnetization is directed in the in-plane direction of the medium is mainly used as the recording method of the HDD. However, considering higher density, perpendicular magnetic recording in which the demagnetizing field near the magnetization reversal boundary is small and sharp reversal magnetization is obtained is more suitable. Further, with respect to thermal fluctuation deterioration, which has recently become a problem in magnetic recording media, the perpendicular medium can be set to have a larger film thickness than the longitudinal recording medium, so that deterioration can be suppressed.

Conventionally, CoCrPt has been used as a perpendicular magnetization film.
And other CoCr-based disordered alloy magnetized films have been mainly studied. However, considering that thermal fluctuation degradation will become a problem in the perpendicular medium in the future, the conventional CoC
A material having a larger perpendicular magnetic anisotropy than that of the r-type is required. As promising candidates, at least one magnetic element selected from Fe, Co and Ni, and Pt, P
Research on ordered phase alloy-based materials in which at least one noble metal element selected from d, Au, and Ir forms an ordered phase has been actively conducted. In particular, fc
FePt and CoPt are ordered alloys with t crystal structure
Are 7 × 10 ⁷ erg / cc and 4 × 10 ⁷ e, respectively.
It is known to have a large magnetic anisotropy of rg / cc in the c-axis direction.

In order to apply a polycrystalline thin film having a large magnetic anisotropy in the c-axis direction to an in-plane or perpendicular magnetic recording medium, it is necessary to grow each crystal grain in an oriented manner. As an effective method of controlling the orientation of the magnetic recording layer by using sputtering, which is a general method of forming a magnetic recording layer, a method of laminating a magnetic thin film on a base having a certain crystallinity is exemplified. In addition, annealing may be performed after and / or during the formation of the magnetic thin film.

More specifically, a method of depositing a perpendicular magnetization film on a {100} oriented MgO single crystal substrate, or a method of depositing a MgO thin film or MgO film as an underlayer on an amorphous substrate such as glass.
A method is disclosed in which a laminated film of a thin film and a seed layer such as Cr or a buffer layer such as Pt is deposited, and a perpendicular magnetization film is deposited thereon (JP-A-9-320847).

However, when the underlayer as described above is used, internal stress is likely to be generated between the underlayer and the magnetic layer thereover due to poor lattice matching. There is a problem that the adhesive force of the magnetic layer is reduced due to the heat load inside and the film is peeled off.

In particular, MgO is chemically unstable because it reacts with moisture or carbon dioxide in the air and shows deliquescence, in addition to poor lattice matching with the magnetic layer. For this reason, Mg
O has a problem that adhesion to a substrate and a magnetic layer or another underlayer is significantly reduced.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing Fe
In the case where a magnetic film having an fct structure represented by a Pt ordered alloy is used, the problem that film peeling easily occurs due to internal stress caused by poor lattice matching between the underlayer and the magnetic layer, An object of the present invention is to provide an in-plane or perpendicular magnetic recording medium having excellent operation characteristics.

[0009]

A magnetic recording medium according to the present invention comprises a substrate, an underlayer formed on the substrate, a magnetic layer formed on the underlayer, and a magnetic layer formed on the magnetic layer. Wherein the underlayer is made of a bulk material that does not show deliquescence.

In the present invention, the magnetic layer is made of crystal grains having an fct structure and contains a magnetic metal element and a noble metal element as main components, and the magnetic metal element is at least selected from the group consisting of Fe, Co and Ni. One kind, and the noble metal element is at least one kind selected from the group consisting of Pt, Pd, Au and Ir.

In the present invention, as the underlayer,
A {100} oriented NaCl-type crystal having a lattice constant of 3.52 to 4.20 is used. Specific examples of the NaCl-type crystal constituting the underlayer include at least one selected from the group consisting of CrN, NiO, TiO, VO, VN, and VC.

In the present invention, as the underlayer,
It may be made of a {100} oriented CsCl type crystal having a lattice constant of 2.49 to 3.00%.

In the present invention, as the underlayer,
{001} consists L1 ₀ type structure or {001} intermetallic compound having an L1 ₂ type structure in the orientation of the orientation and the lattice constant may be used as a 3.52～4.20A.

In the present invention, a second layer composed of {100} oriented fcc crystal grains is provided between the underlayer and the magnetic layer.
May be provided. The lattice constant of the second underlayer made of fcc crystal grains is preferably 3.52 to 4.20 °. Ag, Al, Au, Cu, Ir, Ni, P
Examples include elements, alloys, and compounds containing at least one selected from the group consisting of t, Pd, and Rh.

In the present invention, a second layer composed of {100} oriented bcc crystal grains is provided between the underlayer and the magnetic layer.
May be provided. It is preferable that the lattice constant of the second underlayer made of bcc crystal grains is 2.49 to 3.00 °. Examples of the second underlayer composed of bcc crystal grains include those composed of an element, alloy or compound containing at least one selected from the group consisting of Cr and Fe.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

In the present invention, the substrate is glass,
An amorphous or polycrystalline material such as ceramics is used. A substrate obtained by depositing metal or ceramics on a substrate body made of a hard material may be used as the substrate. In addition, a single crystal substrate of Si, MgO, Al ₂ O ₃ or the like can be used.

In the present invention, a thin film of an underlayer and a magnetic layer is formed on a substrate. As a method for forming a thin film, a vacuum evaporation method, a sputtering method, a chemical vapor deposition method, or a laser ablation method can be used. When forming the underlayer and / or the magnetic layer, the substrate is
Heating to ° C. may be desirable because the ordering of the magnetic layer proceeds. Instead of heating the substrate, bias sputtering for applying RF and / or DC power to the substrate, irradiation of ions or neutral particles to the substrate, or the like may be performed. These processes may be performed not only during film formation but also after film formation or before film formation.

In the present invention, the magnetic layer is composed of crystal grains having an fct structure and contains a magnetic metal element and a noble metal element as main components. The magnetic metal element is at least one selected from the group consisting of Fe, Co and Ni, and the noble metal element is at least one selected from the group consisting of Pt, Pd, Au and Ir. Other elements such as Ta, W, Mo, and B may be added to improve the properties of the magnetic layer. In the present invention, the magnetic layer is formed of a non-magnetic metal such as Cr or Si between magnetic particles.
A configuration in which a dielectric such as O ₂ exists may be used. In the present invention, the magnetic layer may be formed by laminating two or more magnetic layers having different characteristics. In this case, either or both of the exchange coupling interaction and the magnetostatic coupling interaction may be acting between the stacked magnetic layers. One or more nonmagnetic layers may be present between two or more magnetic layers. The configuration of such a magnetic layer is determined by the magnetic characteristics required by the system and the manufacturing process.

When the medium of the present invention is used as a perpendicular magnetic recording medium, the magnetic crystal grains must have an fct structure in which the c-axis is oriented in the direction perpendicular to the film surface. However, not all particles need to satisfy this condition, and the proportion of particles having the fct structure may be 60% or more, and more preferably 80% or more. Regarding the c-axis orientation, the standard deviation of the orientation axis may be within 10 °, more preferably within 5 °.

Whether or not the crystal grains constituting the magnetic layer are regular can be confirmed by a general X-ray diffractometer. If the peaks representing the (001), (002), and (003) planes can be respectively observed, the fct structure exists,
In addition, it can be said that the c-axis is oriented perpendicular to the film surface. (00
Specifically, the intensity of the peaks representing the (1), (002), and (003) planes may be any intensity that is observed as a peak that is significant relative to the background level. Further, even if a (111) peak indicating in-plane orientation is observed, (00)
If the peaks representing the (1), (002), and (003) planes can be observed with higher intensity (100 times or more), it can be said that the c-axis is oriented perpendicular to the film surface. In addition, when the magnetic particles are 10
If the correlation (coherency) of the crystal lattice with the adjacent particles is small, it may appear as amorphous by X-ray diffraction even if the c-axis is oriented perpendicular to the film surface. In such a case, by observing the fine structure using a transmission electron microscope (TEM) or the like, the c-axis perpendicular to the film surface can be confirmed.

The thickness of the magnetic layer is determined by the required value of the system, but is generally preferably smaller than 200 nm, more preferably smaller than 50 nm. However, if the thickness is less than 0.5 nm, the film does not become a continuous film and is not suitable for a magnetic recording medium.

In the present invention, the underlayer is a thin film inserted between the magnetic layer and the substrate to reinforce the function of the magnetic layer as a magnetic recording medium. The underlayer may be a layer composed of one material or a multilayer film composed of several layers. If the underlayer meets the above requirements,
It need not necessarily be a thin film.

The underlayer used in the present invention is made of a substance which does not show deliquescence in bulk. It is not preferable to use a deliquescent substance as the underlayer, because the underlayer absorbs moisture in the air, and the adhesion of the film at that portion is significantly reduced. As deliquescent substances,
Examples include metal elements of Group 1 and Group 2 of the periodic table and oxides thereof.

Here, in order to make the magnetic layer having the fct structure c-axis oriented, the lattice constant is close to that of the magnetic layer as the underlayer and the (100) plane has the same structure as the magnetic layer in consideration of lattice matching. It is desirable to orient the fcc crystal with {100} orientation. However, it is difficult for a single element fcc metal to obtain a {100} orientation with respect to a substrate such as a glass substrate or a polycrystalline substrate that cannot directly correspond to the lattice spacing. On the other hand, the present invention is characterized in that good lattice matching with both the substrate and the magnetic layer is obtained by using a specific underlayer.

In one embodiment of the present invention, the underlayer is made of a thin film made of a {100} oriented NaCl type crystal. In the case of NaCl-type crystals, a {100} oriented film is easily obtained on a substrate such as a glass substrate or a polycrystalline substrate, and the lattice is a face-centered cubic lattice. This is effective to orient vertically. The NaCl type crystal has a general formula MG when considering lattice matching with a magnetic layer composed of fct ordered alloy crystal grains.
(M is at least one selected from the group consisting of Ti, Ta, V, Cr, Co, Fe and Ni, G is B, C,
At least one selected from the group consisting of N and O)
It is preferable to consist of the material represented by these. In particular,
CrN, NiO, TiO, VO, VN, VN
C and the like. One or more other elements may be added to the NaCl-type crystal. As long as the crystal orientation of the magnetic layer and the lattice matching with the magnetic layer are satisfied, the underlayer may have a crystal type different from the NaCl type as a result of the addition of other elements. It is preferable that the lattice constant of the underlayer made of the NaCl type crystal is 3.52 to 4.20 °.

In another embodiment of the present invention, the underlayer is made of a thin film made of {100} oriented CsCl type crystal. The CsCl-type crystal forms a magnetic layer because a {100} oriented film is easily obtained on a substrate such as a glass substrate or a polycrystalline substrate, and the {100} plane can be lattice-matched to the {001} plane of the fct crystal. This is effective for orienting the c-axis of the crystal grain in a direction perpendicular to the film surface. As the CsCl-type crystal, a large number of crystals such as CuPd, MnAl, and NiAl can be cited. These substances have good lattice matching with the fct magnetic layer in the bulk state and are suitable for vertically orienting the fct magnetic layer. Through various experiments,
It has been clarified that even when these substances are deposited on a substrate by sputtering or the like, lattice matching equivalent to that of a bulk substance can be obtained. One or more other elements may be added to the CsCl crystal. As long as the crystal orientation of the magnetic layer and the lattice matching with the magnetic layer are satisfied, as a result of adding other elements to the CsCl crystal, C
A crystal type different from the sCl type may be used. The lattice constant of the underlayer made of the CsCl type crystal is 2.49 to 3.00 °.
It is preferred that

In still another embodiment of the present invention,
L1 underlayer {001} orientation ₀ type structure or {00
1} is made of an intermetallic compound having an L1 ₂ -type structure orientation. {001} orientation of L1 ₀ type structure or {00
1} intermetallic compound having an L1 ₂ -type structure orientations respectively on a substrate such as a glass substrate or a polycrystalline substrate {001} easily obtained alignment film, or {100} orientation film, and the lattice is in face-centered cubic lattice Therefore, it is effective to orient the c-axis of crystal grains constituting the magnetic layer in a direction perpendicular to the film surface. The lattice constant of the underlayer made of such an intermetallic compound is preferably 3.52 to 4.20 °.

In the present invention, a second underlayer made of {100} oriented fcc crystal grains is laminated between the (first) underlayer made of the above NaCl crystal or CsCl crystal and the magnetic layer. You may. Basically, the first underlayer / fc
It may be laminated in the order of c second underlayer / fct magnetic layer. However, since the purpose is to obtain good lattice matching between the layers, as long as this purpose can be achieved, another layer (not necessarily a thin film) may be inserted between the layers. Good. The {100} plane of the fcc crystal is the {0} of the fct crystal.
Atomic sites that have the same geometrical structure as the {01} plane and whose arrangement is substantially the same by the first underlayer are fct
The magnetic layer can have a lattice constant closer to that of the magnetic layer.

Considering the lattice matching between the second underlayer made of fcc crystal grains and the magnetic layer, the lattice constant is 3.5.
Preferably it is 2 to 4.20 °. A substance that satisfies this condition has good lattice matching with the fct magnetic layer in the bulk state, and is suitable for vertically orienting the fct magnetic layer. Specifically, Ag, Al, Au, Cu, Ir, Ni, Pt, and P are used as the second underlayer made of fcc crystal grains.
An element, alloy or compound containing at least one selected from the group consisting of d and Rh can be used.
Various experiments have revealed that even when these materials are deposited on the first underlayer by sputtering or the like, lattice matching equivalent to that of a bulk material can be obtained. One or more other elements may be added to the fcc crystal. As long as the crystal orientation of the magnetic layer and the lattice matching with the magnetic layer are satisfied, a crystal type different from the fcc type may be obtained as a result of adding another element to the second underlayer.

In the present invention, a second underlayer made of {100} oriented bcc crystal grains is laminated between the (first) underlayer made of the above NaCl crystal or CsCl crystal and the magnetic layer. You may. Basically, the first underlayer / bc
It may be laminated in the order of c second underlayer / fct magnetic layer. However, since the purpose is to obtain good lattice matching between the layers, as long as this purpose can be achieved, another layer (not necessarily a thin film) may be inserted between the layers. Good. As shown in FIG. 3, the {200} plane of the bcc crystal and the {001} plane of the fct crystal can be lattice-matched. Therefore, it is possible to make the atomic sites whose arrangement is substantially the same by the first underlayer have a lattice constant closer to the lattice constant of the fct magnetic layer.

In consideration of the lattice matching between the second underlayer made of bcc crystal grains and the magnetic layer, the lattice constant is 2.4.
It is preferably 9 to 3.00 °. A substance that satisfies this condition has good lattice matching with the fct magnetic layer in the bulk state, and is suitable for vertically orienting the fct magnetic layer. Specifically, an element, alloy or compound containing at least one selected from the group consisting of Cr and Fe can be used as the second underlayer made of bcc crystal grains. Various experiments have revealed that even when these materials are deposited on the first underlayer by sputtering or the like, lattice matching equivalent to that of a bulk material can be obtained. One or more other elements may be added to the bcc crystal. As long as the crystal orientation of the magnetic layer and the lattice matching with the magnetic layer are satisfied, a crystal type different from the bcc type may be obtained as a result of adding another element to the second underlayer.

[0033] In the present invention, (first) NaCl-type crystal as the base layer, the one or use of CsCl-type crystal, or L1 ₀ type structure or an intermetallic compound having an L1 ₂ type structure, and the second under the Whether the fcc crystal or the bcc crystal is used as the base layer depends on the material and the forming method of another layer such as the magnetic layer. In consideration of manufacturing cost, it may be preferable not to use the second underlayer.

[0034]

Embodiments of the present invention will be described below with reference to the drawings. In the following examples, magnetic recording media having the structure shown in FIG. 1 or 2 were manufactured. The magnetic recording medium of FIG. 1 has a structure in which an underlayer 21, a magnetic layer 3, and a protective layer 4 are stacked on a substrate 1. The magnetic recording medium of FIG. 2 has a structure in which an underlayer 21, a second underlayer 22, a magnetic layer 3, and a protective layer 4 are stacked on a substrate 1.

The microstructure of the manufactured magnetic layer was evaluated by using an X-ray diffraction method. FIG. 4 shows an X-ray diffraction profile of a sample composed of a glass substrate / VO underlayer / FePt magnetic layer as an example. In FIG. 4, FePt (001), (00
2) and (003) peaks are observed with significant intensity. From this, an ordered FePt phase was formed and (00
1) It can be seen that they are oriented. Similarly, when another underlayer included in the present invention is used, the FePt ordered phase (00)
1) The orientation was confirmed.

The (10) of the first and second underlayers
The (0) orientation or (001) orientation can also be confirmed by X-ray diffraction. Also, the lattice constants of the first and second underlayers are also X
It can be estimated by line diffraction evaluation.

The adhesion of the sample was determined according to JIS K5400-19.
The evaluation was performed as follows based on a peel test (cross-cut tape method) using an adhesive tape specified in No. 90.
The number of cells on the sample surface was 10 at 1 mm intervals with a cutter knife.
After making cuts in a grid pattern so that x10 = 100 pieces, an adhesive tape was stuck and rubbed with an eraser to completely adhere the tape. One minute after the tape was applied, one end of the tape was gripped and pulled off momentarily.
Observe the condition of the wound after peeling it off and observe JIS K5400
Evaluation scores were given as in -1990. Table 1 shows the evaluation criteria of the evaluation score according to the state of the scratch.

[0038]

[Table 1]

The relationship between the adhesion and the characteristics as a magnetic recording medium was examined as follows. As an example, a 70 nm Cr underlayer, a 15 nm CoCrPt magnetic layer, and
Disk samples were prepared by sequentially depositing a 0 nm carbon protective layer. At that time, the glass substrate was subjected to sputter etching before the formation of the Cr underlayer. Also, the sputtering pressure of the Cr underlayer was changed in the range of 0.1 to 10 Pa.
Thirteen samples with different adhesion indices were produced depending on the presence or absence of sputter etching and the difference in sputtering pressure. For these samples, a contact-start-stop (CSS) experiment in which a magnetic head was brought into contact and sliding was performed. The number of times of sliding until the medium was destroyed was measured by abnormal sound generation by the AE sensor and visual inspection, and the logarithmic value was taken as CSS resistance. Figure 5 shows the adhesion index and CS.
The relationship with S resistance is shown. From FIG. 5, it was found that a magnetic recording medium having no problem in CSS operation can be obtained when the adhesion index is 8 or more.

The relationship between the lattice constant and the adhesion index was examined as follows. As an example, a sample having a structure of glass substrate / VN first underlayer / second underlayer / FeNiPt magnetic layer / Pt protective layer was prepared. Here, as the second underlayer,
By changing a composition by selecting a plurality of elements from Pb, Pt, Ni, Ir and Au which are fcc crystals, a crystal having a changed lattice constant was formed. For these samples, the second
The relationship between the lattice constant of the underlayer and the adhesion index (evaluation score) was examined. FIG. 6 shows the result. From this figure, fcc
When the second underlayer made of a crystal was used, it was found that favorable adhesion (evaluation score of 8 or more) was obtained when the lattice constant was 3.52 to 4.20 °.

A sample having a structure of glass substrate / CrN first underlayer / second underlayer / FePtIr magnetic layer / Pt protective layer was prepared. Here, bc is used as the second underlayer.
By changing a composition by selecting a plurality of elements from V, Cr and Fe which are c crystals, a crystal having a changed lattice constant was formed. For these samples, the relationship between the lattice constant of the second underlayer and the adhesion index (evaluation score) was examined. As a result, it was found that in the case of using the second underlayer made of the bcc crystal, if the lattice constant was 2.49 to 3.00 °, favorable adhesion (eight or more evaluation points) could be obtained.

Example 1 A magnetic recording medium shown in FIG. 1 was manufactured as follows using a base layer made of NaCl type crystal.

The disk-shaped glass substrate was placed in a multi-chamber sputtering apparatus, and the pressure in the vacuum chamber was reduced to 2 × 10 ⁻⁵ or less, and the chamber was evacuated.
Ar atmosphere of 10 nm by RF sputtering
The underlayer made of the NaCl type crystal was formed. In a state where the substrate is heated to 500 ° C. in the next vacuum chamber, DC
A 50 nm magnetic layer was formed by sputtering. 2 nm by DC sputtering in the next vacuum chamber
A protective layer made of Pt was formed.

The first underlayer is made of NaCl type crystal, and the second underlayer is made of fcc crystal or b
A magnetic recording medium shown in FIG. 2 was manufactured as follows using a cc crystal.

In the same manner as described above, a 50 nm-thick first underlayer made of a NaCl-type crystal is formed on a glass substrate by RF sputtering, and a first underlayer is formed by DC sputtering.
A second underlayer made of a 0 nm fcc crystal is formed, a 50 nm magnetic layer is formed by DC sputtering while the substrate is heated to 500 ° C., and a 2 nm protective layer made of Pt is formed by DC sputtering. did.

Similarly, a first underlayer made of a 50 nm NaCl crystal is formed on a glass substrate by RF sputtering, and a 50 nm bc is formed by DC sputtering.
A second underlayer made of c-crystal is formed, and the substrate is heated to 500 ° C.
A magnetic layer having a thickness of 50 nm is formed by DC sputtering in a state where the magnetic layer is heated, and a P layer having a thickness of
A protective layer made of t was formed.

Table 2 shows the materials used. Samples using MgO or TiB as the first underlayer and Pb or V as the second underlayer are comparative examples.

According to the X-ray diffraction, the fcc crystal or bc
It was found that the second underlayer of the c-crystal was (100) -oriented, and the magnetic layer mainly had the (001) -oriented fct structure. Further, as a result of evaluating the magnetic characteristics of the manufactured magnetic recording medium by using the VSM, it was found that all the samples were perpendicular magnetization films in which the easy magnetization direction was perpendicular to the film surface.

Table 2 also shows the evaluation scores of the adhesion test. From Table 2, it can be seen that a sample using an appropriate material for the first underlayer or the first and second underlayers can obtain good adhesion.

[0050]

[Table 2]

When VO, NiO, and TiO are formed by reactive sputtering with oxygen being introduced at a partial pressure of several percent, V
The same results as in Table 2 were obtained when N and CrN were formed by reactive sputtering with nitrogen introduced, and when VC was formed by reactive sputtering with a carbon source such as methane introduced.

Example 2 A magnetic recording medium shown in FIG. 1 was manufactured as follows using an underlayer made of CsCl type crystal.

In the same manner as in Example 1, the disk-shaped Si
10 nm CsCl by DC sputtering on the substrate
An underlayer made of a type crystal was formed. With the substrate heated to 500 ° C. in the next vacuum chamber, a 50 nm magnetic layer was formed by DC sputtering. A protective layer made of 2 nm of Pt was formed by DC sputtering in the next vacuum chamber.

The first underlayer is made of CsCl type crystal, and the second underlayer is made of fcc crystal or b
A magnetic recording medium shown in FIG. 2 was manufactured as follows using a cc crystal.

In the same manner as above, a first underlayer made of a CsCl type crystal of 50 nm is formed on a Si substrate by DC sputtering, and a first underlayer of 100 nm is formed by DC sputtering.
A second underlayer made of a fcc crystal of nm is formed, a magnetic layer of 50 nm is formed by DC sputtering while the substrate is heated to 500 ° C., and a protective layer of Pt of 2 nm is formed by DC sputtering. did.

Similarly, a first underlayer made of a 50 nm CsCl type crystal is formed on a Si substrate by DC sputtering, and a 50 nm bcc is formed by DC sputtering.
A second underlayer made of a crystal is formed, a 50 nm magnetic layer is formed by DC sputtering while the substrate is heated to 500 ° C., and a 2 nm Pt is formed by DC sputtering.
Was formed.

Tables 3 and 4 show the materials used. A sample using MgO or BaCd as the first underlayer and Pb or Eu as the second underlayer is a comparative example.

According to X-ray diffraction, fcc crystal or bc
It was found that the second underlayer of the c-crystal was (100) -oriented, and the magnetic layer mainly had the (001) -oriented fct structure.

Tables 3 and 4 also show the evaluation scores of the adhesion test. From these tables, for samples using an appropriate material for the first underlayer or the first and second underlayers,
It can be seen that good adhesion can be obtained.

[0060]

[Table 3]

[0061]

[Table 4]

Further, as a result of examining the relationship between the lattice constant of the second underlayer and the adhesion index (evaluation score) in the same manner as described above, the lattice constant of the second underlayer made of fcc crystal was 3. It was found that if the lattice constant of the second underlayer made of bcc crystal was 52 to 4.20 ° and the lattice constant was 2.49 to 3.00 °, favorable adhesion (8 or more evaluation points) could be obtained.

[0063] Using anything by intermetallic compounds having an L1 ₀ type structure or L1 ₂ -type structure as Example 3 underlayer was fabricated a magnetic recording medium shown in FIG. 1 as follows.

In the same manner as in Example 1, an underlayer of 10 nm was formed on a disc-shaped crystallized glass substrate by DC sputtering. Substrate 50 in the next vacuum chamber
50n by DC sputtering with heating to 0 ° C
m magnetic layers were formed. A protective layer made of 2 nm of Pt was formed by DC sputtering in the next vacuum chamber.

[0065] Further, those made of an intermetallic compound having an L1 ₀ type structure or L1 ₂ type structure as a first base layer,
A magnetic recording medium shown in FIG. 2 was manufactured as follows using a second underlayer made of fcc crystal or bcc crystal.

In the same manner as described above, a first underlayer of 50 nm was formed on a crystallized glass substrate by DC sputtering, and a second underlayer of 100 nm fcc crystal was formed by DC sputtering. Was heated to 500 ° C., a 50 nm magnetic layer was formed by DC sputtering, and a 2 nm protective layer made of Pt was formed by DC sputtering.

Similarly, a first underlayer of 50 nm is formed on a crystallized glass substrate by DC sputtering.
Forming a second underlayer made of a 50 nm bcc crystal by sputtering, forming a 50 nm magnetic layer by DC sputtering while heating the substrate to 500 ° C.,
A 2 nm Pt protective layer was formed by DC sputtering.

Tables 5 to 7 show the materials used. Samples using MgO or Pt ₃ Sc as the first underlayer and Pb or Eu as the second underlayer are comparative examples.

According to X-ray diffraction, fcc crystal or bc
It was found that the second underlayer of the c-crystal was (100) -oriented, and the magnetic layer mainly had the (001) -oriented fct structure.

Tables 5 to 7 also show evaluation scores of the adhesion test. From these tables, it can be seen that a sample using an appropriate material for the first underlayer or the first and second underlayers can obtain good adhesion.

[0071]

[Table 5]

[0072]

[Table 6]

[0073]

[Table 7]

Further, as a result of examining the relationship between the lattice constant of the second underlayer and the adhesion index (evaluation score) in the same manner as described above, the lattice constant of the second underlayer made of fcc crystal was 3. It was found that if the lattice constant of the second underlayer made of bcc crystal was 52 to 4.20 ° and the lattice constant was 2.49 to 3.00 °, favorable adhesion (8 or more evaluation points) could be obtained.

[0075]

As described in detail above, according to the present invention, F
When a magnetic film having an fct structure typified by an ePt ordered alloy is used, the adhesion between the underlayer and the magnetic layer can be improved, and an in-plane or perpendicular magnetic recording medium having excellent operation characteristics can be provided. be able to.

[Brief description of the drawings]

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

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

FIG. 3 is a schematic diagram showing lattice matching between a bcc {100} plane and an fct {001} plane.

FIG. 4 is a view showing an X-ray diffraction profile of a FePt magnetic layer in an example of the present invention.

FIG. 5 is a diagram showing a relationship between an adhesion index and CSS resistance in an example of the present invention.

FIG. 6 is a diagram showing the relationship between the lattice constant of a second underlayer and the evaluation score of an adhesion index in an example of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 21 ... Underlayer 22 ... Second underlayer 3 ... Magnetic layer 4 ... Protective layer

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Katsutaro Ichihara 1st address, Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa F-term in Toshiba R & D Center (reference) 5D006 BB01 BB07 CA01 CA05 CA06 DA03 DA08 FA09

Claims (12)

[Claims] 1. A magnetic recording medium having a substrate, an underlayer formed on the substrate, and a magnetic layer formed on the underlayer, wherein the underlayer is made of a material that is bulk and does not show deliquescence. A magnetic recording medium characterized by being constituted. 2. The magnetic layer is made of crystal grains having an fct structure and contains a magnetic metal element and a noble metal element as main components, and the magnetic metal element is at least one selected from the group consisting of Fe, Co and Ni. The magnetic recording medium according to claim 1, wherein the noble metal element is at least one selected from the group consisting of Pt, Pd, Au, and Ir. 3. The underlayer is made of {100} oriented NaC.
It is composed of an l-type crystal and has a lattice constant of 3.52-4.
3. The magnetic recording medium according to claim 1, wherein the angle is 20 [deg.]. 4. The magnetic recording according to claim 3, wherein the NaCl-type crystal constituting the underlayer is at least one selected from the group consisting of CrN, NiO, TiO, VO, VN and VC. Medium. 5. The method according to claim 1, wherein the underlayer is CsC of {100} orientation.
It is composed of an l-type crystal and has a lattice constant of 2.49 to 3.
3. The magnetic recording medium according to claim 1, wherein the angle is 00 °. Wherein said underlayer, {001} L1 orientation ₀
Made from the mold structure or {001} intermetallic compound having an L1 ₂ -type structure orientation, and its lattice constant 3.52～
3. The magnetic recording medium according to claim 1, wherein the angle is 4.20 °. 7. The method according to claim 1, wherein the difference between the underlayer and the magnetic layer is $ 10.
7. The magnetic recording medium according to claim 1, further comprising a second underlayer made of fcc crystal grains of 0 ° orientation. 8. The magnetic recording medium according to claim 7, wherein the lattice constant of the second underlayer made of fcc crystal grains is 3.52 to 4.20 °. 9. The method according to claim 9, wherein the second underlayer made of fcc crystal grains is made of Ag, Al, Au, Cu, Ir, Ni, Pt, Pd.
9. The magnetic recording medium according to claim 7, comprising an element, alloy or compound containing at least one selected from the group consisting of Rh and Rh. 10. The method according to claim 1, wherein the difference between the underlayer and the magnetic layer is
7. The magnetic recording medium according to claim 1, further comprising a second underlayer made of bcc crystal grains having a 00 [deg.] Orientation. 11. The magnetic recording medium according to claim 10, wherein a lattice constant of the second underlayer made of bcc crystal grains is 2.49 to 3.00 °. 12. The method according to claim 10, wherein the second underlayer made of bcc crystal grains is made of an element, alloy or compound containing at least one selected from the group consisting of Cr and Fe. 12. The magnetic recording medium according to item 11,