JPH11175945A - Magnetic storage device and intrasurface magnetic recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize low medium noise and high output resolution by constituting of the substrate, which is located between a magnetic layer and a base plate, with a first substrate on the base plate side and a second substrate on the magnetic layer side, constructing the first substrate with a two element alloy having the body centered three-dimensional structure with a complete solid solution equilibrium diagram and constructing the second substrate with a two element alloy having the body centered three-dimensional structure having a non-complete solid solution equilibrium diagram. SOLUTION: It is desired that in the first substrate, Cr is selected as a main component and the element selected from V, Mo and W is included. In the second substrate, Cr is selected as a main component and the element selected from Ti, Ta, Nb and Zr is included. To be more specific, CoCrNi, CoCrTa and CoCrNiPt alloys are suitable for the first substrate and CrTi, CrTa and CrNb alloys are suitable for the second substrate. In order to maintain a good crystal combination and to prevent the increase in the particle diameters, it is desirable that the film thickness of the first substrate is set to 3 to 10 nm and the film thickness of the second substrate is made >=15 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic storage device and a longitudinal magnetic recording medium, and more particularly to a magnetic storage device having a recording density of 3 gigabits per square inch or more, and a longitudinal magnetic recording for realizing the same. Regarding the medium.

[0002]

2. Description of the Related Art The amount of information handled by computers is steadily increasing, and magnetic disk drives as external storage devices are required to have ever larger capacities. At present, magnetic disk drives having a recording density of a maximum of 2 gigabits per square inch have been commercialized. For the magnetic head of such a high-density magnetic disk device, a recording section and a reproducing section are separated, and a composite type head using an electromagnetic induction type magnetic head for the recording section and a magnetoresistive head for the reproducing section is adopted. ing. Since the magnetoresistive head has higher reproduction sensitivity than the conventional electromagnetic induction type head, a sufficient reproduction output can be obtained even when the recording bits are miniaturized and the leakage magnetic flux is reduced. In addition, the development of a giant magnetoresistive head of the spin valve type with further improved reproduction sensitivity is also progressing.

On the other hand, a magnetic recording medium is made of CoCrTa, Co
It comprises a Co alloy magnetic layer such as CrPt and a Cr underlayer for controlling the crystal orientation of the magnetic layer. Since the Co alloy magnetic layer has a hexagonal close-packed (hcp) structure with the c-axis as the magnetic easy axis,
For use as an in-plane magnetic recording medium, it is desirable that the c axis be directed in the plane. Therefore, the body-centered cubic (bc
c) A method is used in which a Cr underlayer having a structure is formed, a Co alloy magnetic layer is epitaxially grown thereon, and the c-axis is directed in-plane. In addition, the magnetic layer of a high-density recording medium requiring a high coercive force includes CoCrP having a large lattice constant.
Since a t alloy is used, the lattice spacing is increased by adding Ti or V to Cr, the lattice matching with the magnetic layer is enhanced, and the c-axis is oriented more in-plane (Japanese Patent Laid-Open No. 62-257618, JP
63-197018) has been proposed.

When a magnetoresistive head is used as a reproducing head, not only signals from the medium but also noise are reproduced with high sensitivity. Therefore, the medium is required to have lower noise than before. Medium noise is mainly caused by disturbance of magnetization in a magnetization transition region between recording bits, and narrowing this region leads to reduction of medium noise. For this purpose, it is effective to make the magnetic particles finer, weaken the interaction between the particles, and reduce the size of the magnetization reversal. As described above, since an epitaxial relationship is established between the magnetic layer and the underlayer, the magnetic particles can be miniaturized by miniaturizing the underlayer. Further, the interaction between particles can be reduced by increasing the Cr concentration and the film forming temperature of the magnetic layer to segregate nonmagnetic Cr at the grain boundaries.

[0005]

However, when the underlayer is thinned or other elements are added in order to make the underlayer finer, the crystal orientation of the underlayer is reduced, and the magnetic layer is accordingly reduced. The in-plane orientation component of the c-axis decreases. As a result, there arise problems such as a decrease in output resolution of a medium which is indispensable for higher recording density.

The present invention has been made to solve the above problems. More specifically, a magnetic storage device having high reliability at a recording density of 3 gigabits per square inch or more, and a longitudinal magnetic recording medium with low medium noise and high output resolution for realizing the same. The purpose is to provide.

[0007]

According to the present invention, there is provided an in-plane magnetic recording medium having a magnetic layer formed on a substrate via an underlayer, a driving unit for driving the recording medium in a recording direction, a recording unit and a reproducing unit. Magnetic head, means for moving the magnetic head relative to the in-plane magnetic recording medium, and recording / reproduction signal processing for performing signal input to the magnetic head and reproduction of an output signal from the magnetic head A reproducing section of the magnetic head is constituted by a magnetoresistive head, and the underlayer of the longitudinal magnetic recording medium is a first underlayer on the substrate side and a second underlayer on the magnetic layer side. Wherein the first underlayer is a binary alloy having a substantially body-centered cubic structure having an equilibrium diagram of an all-solid solution system, and the second underlayer is an equilibrium of a non-exclusive solid solution system. Substantially body-centered cubic binary alloy with phase diagram By, to achieve the above object.

The magnetic layer of the longitudinal magnetic recording medium is made of CoC.
rNi, CoCrTa, CoCrPt, CoCrNiP
An alloy containing Co as a main component, such as t, CoCrPtTa, and CoCrPtTi, can be used. In particular, a Co alloy to which Pt is added has a high anisotropic magnetic field and can easily obtain a high coercive force, and thus is suitable for high recording density. Where P
Since the coercive force tends to increase with the addition of t, it is necessary to select the Pt concentration in accordance with the write performance of the recording head.

For use as an in-plane magnetic recording medium, Co
It is necessary to direct the c-axis of the alloy magnetic layer in the plane of the film. Such a crystal orientation can be obtained by forming a magnetic layer on an underlayer having a bcc structure and having its (100) plane oriented substantially parallel to the film plane. The present inventors have studied various underlayers in order to achieve good c-axis in-plane orientation of the magnetic layer and miniaturization of the particles, and found that the underlayer had a two-layer structure, and the first underlayer had a solid content. It is found that it is effective to use a binary alloy having a bcc structure having an equilibrium diagram of a solution system and to use a binary alloy having a bcc structure having an equilibrium diagram of a non-percentage solid solution for the second underlayer. Was.

When a binary alloy having a bcc structure having an equilibrium phase diagram of a solid solution system is used for the first underlayer, good (100) is obtained even when the film thickness is reduced in order to reduce the underlayer grain size.
An orientation is obtained. As a specific material of the first underlayer, a Cr alloy such as CrMo, CrV, or CrW is desirable. However, these alloys having an equilibrium phase diagram of a solid solution system have a tendency that the particle size tends to increase significantly with the film thickness. The thickness of the first underlayer is preferably 3 nm or more and 10 nm or less from the viewpoint of maintaining good crystal orientation and suppressing an increase in particle size. Further, the first underlayer may be made of an alloy composed of three kinds of elements. However, it is necessary to use a binary equilibrium phase diagram composed of a combination of these elements with a solid solution system.

When a binary alloy having a bcc structure having an equilibrium state diagram of a non-percent solid solution system is used for the second underlayer, the particles of the magnetic layer are finer than in the case of using a pertinent solid solution alloy. Tend to be. This is the Journal of Applied
Physics (J. Appl. Phys.), Vol. 73, 5566 (1
993) and the like, a so-called bicrystal structure in which a plurality of (11.0) -oriented hcp magnetic grains grow on one (100) -oriented bcc base grain so that the c-axes are orthogonal to each other. This is probably because the frequencies are different. It is not clear why the frequency of having a bicrystal structure is different, but when a non-percentage solid solution alloy is used,
It is considered that there is non-uniformity such as composition fluctuations and defects in one base particle, and such non-uniformity increases the frequency of the bicrystal structure, and as a result, the magnetic particles are finer.

The specific material of the second underlayer is Cr
Cr alloys such as Ti, CrTa and CrNb are desirable. The thickness of the second underlayer is 15 nm from the viewpoint of suppressing an increase in the particle size.
It is desirable to do the following. The second underlayer does not necessarily need to be a binary alloy, and may be an alloy composed of three or more elements. However, at least one kind of combination in the binary equilibrium diagram consisting of a combination of these elements needs to be a non-percentage solid solution system.

It is necessary to use a substrate having excellent surface smoothness. Specifically, an Al—Mg substrate, a glass substrate, a SiO ₂ substrate, a SiC substrate, a carbon substrate, etc., having NiP formed on the surface thereof may be used. Can be used. If the material of the substrate has poor adhesion to the first underlayer, or if the desired crystal orientation of the first underlayer cannot be obtained, the substrate and the first
Such a problem is solved by forming a substantially amorphous precoat layer between the undercoat layer and the base layer.

The protective layer of the magnetic layer has a thickness of 10 to 30 nm.
Is formed, and a lubricating layer of perfluoroalkyl polyether or the like is formed with a thickness of 2 to 20 nm, whereby a highly reliable in-plane magnetic recording medium can be obtained. Further, by using hydrogenated carbon, silicon carbide, or the like as a material for the protective layer, sliding resistance and corrosion resistance can be improved.

The magnetoresistive sensor portions of the reproducing magnetoresistive magnetic head used in the magnetic storage device of the present invention have a mutual resistance of 0.3.
It is formed between two shield layers made of soft magnet and separated by a distance of 5 μm or less. If the distance between the shield layers is larger than 0.35 μm, the resolution is undesirably reduced.

Further, the magneto-resistance effect type magnetic head is provided between a plurality of conductive magnetic layers that generate a large resistance change by their magnetization directions relatively changing by an external magnetic field, and the conductive magnetic layers. By being constituted by a magnetoresistive sensor including a conductive nonmagnetic layer disposed,
Since the reproduction signal can be increased, a highly reliable magnetic storage device with a recording density of 3 gigabits per square inch or more can be realized.

[0017]

(Embodiment 1) FIGS. 2A and 2B are a schematic plan view and a schematic longitudinal sectional view, respectively, of a magnetic storage device according to this embodiment. This apparatus uses an in-plane magnetic recording medium 2
1, a driving unit 22 for rotating the magnetic head 1 and a magnetic head 2
3 and a magnetic storage device having a well-known configuration including a driving means 24 for the magnetic head and a recording / reproducing signal processing means 25 for the magnetic head.

FIG. 3 shows a schematic diagram of the structure of the magnetic head used in the magnetic storage device. This magnetic head is a recording / reproducing separation head in which an electromagnetic induction type magnetic head for recording and a magnetoresistive head for reproduction formed on a magnetic head slider base 37 are combined.

The recording magnetic head includes a pair of recording magnetic poles 3.
This is an inductive type thin-film magnetic head comprising 1, 32 and a coil 33 linked to it, and the gap layer thickness between the recording magnetic poles is 0.3.
It was 3 μm. Each of the magnetic poles 32 is paired with a magnetic shield layer 36 having a thickness of 1 μm, and also serves as a magnetic shield for a reproducing magnetic head. The distance between the shield layers is 0.25.
μm. The reproducing magnetic head is a magnetoresistive head including a magnetoresistive sensor 34 and a conductor layer 35 serving as an electrode. In FIG. 3, the gap layer between the recording magnetic poles and the shield layer are omitted.

FIG. 4 shows a longitudinal sectional structure of the magnetoresistive sensor. The signal detection region 41 of the magnetoresistive sensor is composed of a portion in which a lateral bias layer 43, a separation layer 44, and a magnetoresistive ferromagnetic layer 45 are sequentially formed on a gap layer 42 of Al oxide. For the magnetoresistive ferromagnetic layer 45, a 20 nm NiFe alloy was used. Although 25 nm of NiFeNb was used for the lateral bias layer 43, a ferromagnetic alloy such as NiFeRh having a relatively high electric resistance and good soft magnetic properties may be used. The lateral bias layer 43 is magnetized in an in-plane direction (lateral direction) perpendicular to the current by a magnetic field induced by a sense current flowing through the magnetoresistive ferromagnetic layer 45, and a lateral bias is applied to the magnetoresistive ferromagnetic layer 45. Apply a magnetic field. Thus, the magnetic sensor can obtain a linear reproduction output with respect to the leakage magnetic field from the medium.

The separation layer 44 for preventing the shunt of the sense current from the magnetoresistive ferromagnetic layer 45 has a relatively high electric resistance of Ta.
And the film thickness was 5 nm. At both ends of the signal detection region 41, there are tapered portions 46 processed into a tapered shape.
The tapered portion 46 includes a permanent magnet layer 47 for converting the magnetoresistive magnetic layer 45 into a single magnetic domain, and a pair of electrodes 48 formed on the permanent magnet layer 47 for extracting a signal. It is important that the permanent magnet 47 has a high coercive force and the magnetization direction does not easily change, and CoCr, CoCrPt alloy, or the like is used.

FIG. 1 shows the film configuration of the magnetic recording medium used in this embodiment. As the substrate 11, an Al—Mg alloy substrate having an outer diameter of 95 mmφ and NiP plating on the surface was used. A 5 nm Cr-20 at% Mo alloy layer is used as the first underlayer 12, and a 5 nm Cr-20 at% T is used as the second underlayer 13.
The i-alloy layer is formed of 18 nm Co-22a as the magnetic layer 14.
A t% Cr-10at% Pt alloy layer and a 10 nm carbon layer as the protective layer 15 were continuously formed by DC magnetron sputtering. The deposition conditions were as follows: the partial pressure of argon gas was 5 mTorr, the input power was 1 kW, and the substrate temperature was 3
The temperature was set to 00 ° C. The lubricating layer 16 was applied by diluting a perfluoroalkyl polyether-based material with a fluorocarbon material. As a comparative example, as shown in FIG.
2 was made into a single layer. Here, the thickness of the underlayer 52 was set to 10 nm, and two kinds of compositions of a Cr-20 at% Mo alloy layer (Comparative Example 1) and a Cr-20 at% Ti alloy layer (Comparative Example 2) were used.

225 kFCI was used for the media of this embodiment and the comparative example.
A signal was written at a linear recording density of, and medium noise and output resolution were measured. Table 1 shows the results. Here, as the medium noise, a value normalized by multiplying the measured medium noise by the square root of the reproduction track width and dividing by the reproduction output of 5 kFCI was used. The output resolution was expressed as a percentage obtained by dividing the reproduction output of 225 kFCI by the reproduction output of 5 kFCI.

The medium of this embodiment realizes low medium noise and high output resolution, and it is understood that the medium is suitable for high-density recording. In the medium of Comparative Example 1, the output resolution was relatively high, but the medium noise was increased. This is because the CrMo alloy as the underlayer has an equilibrium diagram of a solid solution system, so that the particle size of the underlayer does not become so fine, and
It is considered that the frequency of the magnetic particles having a bicrystal structure is reduced due to the high uniformity in the underlying particles, and as a result, the magnetic particles are not so fine.

In the medium of Comparative Example 2, the medium noise was low, but the output resolution was low. The medium noise is reduced because the underlayer CrTi alloy has a non-percentage solid solution equilibrium diagram, so that the underlayer particle size becomes finer and the magnetic particles have a bicrystal structure due to non-uniformity in the underlayer. It is considered that the frequency of taking was increased, and as a result, the magnetic particles were miniaturized.

[0026]

[Table 1]

The decrease in output resolution is caused by the (100)
It is considered that the orientation became weak, and as a result, the in-plane component of the c-axis of the magnetic layer decreased. In the medium of this embodiment, since the first underlayer is a CrMo alloy having an all-solid-solution system equilibrium diagram, even if the film thickness is as thin as 5 nm, it is strong (10%).
0) It shows orientation and the underlying particle size is small due to the thin film thickness. Since the second underlayer formed thereon is a CrTi alloy having a (100) orientation while maintaining a (100) orientation because of epitaxial growth, non-uniformity is present in the underlayer particles. As a result, the frequency of the magnetic particles having a bicrystal structure increases.

That is, it is considered that the medium of the present embodiment can realize low medium noise and high output resolution because the c-axis of the magnetic layer is oriented in the film plane and the particles are finer.

The medium of this embodiment is incorporated in the above magnetic storage device, and the head flying height is 30 nm and the linear recording density is 260 kF.
When the recording and reproduction characteristics were evaluated under the conditions of CI and track density of 13 kTPI, an apparatus S / N of 1.7 was obtained. Further, by performing an 8-9 code modulation process on the input signal to the magnetic head, in a temperature range of 10 ° C. to 50 ° C.,
Recording and reproduction could be performed at a recording density of 3 gigabits per square inch. In addition, the number of bit errors after 50,000 head seek tests from the inner circumference to the outer circumference was 10 bits / plane or less, and 300,000 hours at an average failure interval could be achieved.

(Embodiment 2) With the same layer structure as the medium of Embodiment 1, the first underlayer 12 is made of Cr-10 at% of 5 nm.
Mo-10 at% V was used, and 5 nm Cr-15 at% Ti-5 at% B was used as the second underlayer 13. Substrate 1
1, the magnetic layer 14, the protective layer 15, the lubricating layer 16, and the film forming conditions are the same as those of the medium of the first embodiment.

A signal was written to the medium of this embodiment at a linear recording density of 225 kFCI, and the medium noise and output resolution were measured. Table 1 also shows the results. As for the medium noise and the output resolution, values equivalent to those of the medium of Example 1 were obtained. This is because the CrMoV alloy of the first underlayer has an equilibrium diagram of a solid solution system in any combination of elements, and the CrTiB alloy of the second underlayer has a non-total solid solution in which B hardly dissolves in Cr. Example 1 to have the equilibrium diagram of the solid solution system
It is considered that low medium noise and high medium resolution were obtained for the same reason as described for the medium.

The medium of this embodiment is incorporated in the magnetic storage device of the first embodiment, and the head flying height is 30 nm and the linear recording density is 26.
When the recording / reproducing characteristics were evaluated under the conditions of 0 kFCI and a track density of 13 kTPI, an apparatus S / N of 1.8 was obtained. Further, by subjecting the input signal to the magnetic head to 8-9 code modulation, recording and reproduction could be performed at a recording density of 3 gigabits per square inch in a temperature range of 10 ° C. to 50 ° C. In addition, the number of bit errors after 50,000 head seek tests from the inner circumference to the outer circumference was 10 bits / plane or less, and 300,000 hours at an average failure interval could be achieved.

(Embodiment 3) FIG. 6 shows a film configuration of a magnetic recording medium used in this embodiment. The substrate 61 is made of chemically strengthened glass having an outer diameter of 65 mmφ, and the precoat layer 62 is made of 50 nm.
Co-30 at% Cr-10 at% Zr alloy was used.
The first underlayer 12, the second underlayer 13, the magnetic layer 14, the protective layer 15, the lubricating layer 16 and the film forming conditions are the same as in the medium of the first embodiment. As a comparative example, a medium (Comparative Example 3) in which the first underlayer 12 was directly formed on the substrate 61 without using the precoat layer 62 was manufactured.

225 kFC was used for the media of this embodiment and Comparative Example 3.
A signal was written at a recording density of I, and medium noise and output resolution were measured. Table 1 also shows the results. In the medium of the present embodiment, both the medium noise and the output resolution were equivalent to those of the medium of the first embodiment. However, in the medium of Comparative Example 3, the medium noise increased significantly and the output resolution decreased significantly. .

When the crystal orientation was examined by the X-ray diffraction method, it was found that the first and second underlayers of the medium of this embodiment were (10%).
0) While the medium of Comparative Example 3 was oriented,
And the second underlayer was (110) oriented. Comparative Example 3
In the case of such crystal orientation, since the magnetic layer does not have a bicrystal structure, the magnetic particles are not miniaturized, and c
The orientation is such that the axis rises about 28 degrees from the film surface. Thus, it is considered that the medium noise increased and the output resolution decreased. Incidentally, the pre-coat layer of the medium of the present embodiment,
Since the halo has a peak, it is considered to be amorphous.

As described above, when a substrate made of glass or the like in which the (100) orientation of the underlayer is difficult to obtain is used, it is effective to insert an amorphous precoat layer between the substrate and the first underlayer. It can be seen that it is.

The medium of this embodiment is incorporated in the magnetic storage device of the first embodiment, and the head flying height is 30 nm and the linear recording density is 26.
When the recording / reproducing characteristics were evaluated under the conditions of 0 kFCI and a track density of 13 kTPI, an apparatus S / N of 1.8 was obtained. Further, by subjecting the input signal to the magnetic head to 8-9 code modulation, recording and reproduction could be performed at a recording density of 3 gigabits per square inch in a temperature range of 10 ° C. to 50 ° C. In addition, the number of bit errors after 50,000 head seek tests from the inner circumference to the outer circumference was 10 bits / plane or less, and 300,000 hours at an average failure interval could be achieved.

(Embodiment 4) In a magnetic storage device having a configuration similar to that of Embodiment 1, it is preferable to use a spin valve type as shown in FIG. Signal detection area 7 of magnetic sensor
Reference numeral 1 denotes a 5 nm Ta buffer layer 73, a 7 nm first magnetic layer 74, a 1.5 nm Cu intermediate layer 75, a 3 nm second magnetic layer 76, a 10 nm
Has a structure in which the Fe-20 at% Mn antiferromagnetic alloy layer 77 is sequentially formed.

The first magnetic layer 74 has Ni-20 at% F
e alloy was used, and Co was used for the second magnetic layer 76. The exchange magnetic field from the antiferromagnetic alloy 77 causes the second magnetic layer 7
The magnetization of No. 6 is fixed in one direction. In contrast, the second
The first magnetic layer 76 and the nonmagnetic intermediate layer 75
The direction of magnetization of the magnetic layer 74 changes due to the leakage magnetic field from the longitudinal magnetic recording medium. With the change in the relative directions of the magnetizations of the two magnetic layers, the resistance of the entire three layers changes. This phenomenon is called a spin valve effect.

In this embodiment, a spin-valve magnetic head utilizing this effect is used for the magnetoresistive sensor. In addition, the tapered portion 78 composed of the permanent magnet layer 79 and the electrode 80
Is similar to the magnetoresistive sensor shown in FIG.

The medium described in the third embodiment was incorporated in the above-mentioned magnetic storage device, and the head flying height was 30 nm and the linear recording density was 26.
When the recording and reproducing characteristics were evaluated under the conditions of 0 kFCI and a track density of 13 kTPI, an apparatus S / N of 2.0 was obtained. Further, by subjecting the input signal to the magnetic head to 8-9 code modulation, recording and reproduction could be performed at a recording density of 3 gigabits per square inch in a temperature range of 10 ° C. to 50 ° C. In addition, the number of bit errors after 50,000 head seek tests from the inner circumference to the outer circumference was 10 bits / plane or less, and 300,000 hours at an average failure interval could be achieved.

[0042]

According to the longitudinal magnetic recording medium of the present invention, the crystal orientation can be controlled by the first underlayer, the frequency of the bicrystal structure of the magnetic layer can be increased by the second underlayer, and the magnetic particles can be miniaturized. , Low medium noise and high output resolution. By combining the longitudinal magnetic recording medium of the present invention and a magnetoresistive head, a highly reliable magnetic storage device with a recording density of 3 gigabits per square inch or more can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a layer structure of a longitudinal magnetic recording medium according to an embodiment of the present invention.

FIG. 2A is a schematic plan view of a magnetic storage device according to an embodiment of the present invention, and FIG.

FIG. 3 is a schematic three-dimensional view showing a cross-sectional structure of a magnetic head in the magnetic storage device of the present invention.

FIG. 4 is a longitudinal sectional view of a magnetoresistive sensor section of a magnetic head in the magnetic storage device of the present invention.

FIG. 5 is a sectional view showing a layer configuration of a longitudinal magnetic recording medium according to a comparative example of the present invention.

FIG. 6 is a sectional view showing a layer structure of the longitudinal magnetic recording medium according to one embodiment of the present invention.

FIG. 7 is a longitudinal sectional view of a spin valve type magnetoresistive sensor section of a magnetic head in the magnetic storage device of the present invention.

[Explanation of symbols]

11 ... substrate, 12 ... first underlayer, 13 ... second underlayer, 1
4 magnetic layer, 15 protective layer, 16 lubricating layer, 21 in-plane magnetic recording medium, 22 in-plane magnetic recording medium drive, 23
Magnetic head, 24: magnetic head drive unit, 25: recording / reproducing signal processing system, 31: recording magnetic pole, 32: magnetic pole and magnetic shield layer, 33: coil, 34: magnetoresistive element, 35 ...
Conductor layer, 36: magnetic shield layer, 37: slider base,
41: signal detection area of the magnetic sensor, 42: gap layer,
43 ... lateral bias layer, 44 ... separation layer, 45 ... magnetoresistive ferromagnetic layer, 46 ... taper portion, 47 ... permanent magnet layer, 48 ...
Electrodes, 51: Underlayer, 61: Substrate, 62: Precoat layer, 71: Signal detection region of magnetic sensor, 72: Gap layer, 73: Buffer layer, 74: First magnetic layer, 75: Intermediate layer, 76 ... Second magnetic layer, 77... Antiferromagnetic alloy layer, 7
8: tapered portion, 79: permanent magnet layer, 80: electrode.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Joe Hosoe 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Inside Central Research Laboratory, Hitachi, Ltd.

Claims (11)

[Claims] 1. An in-plane magnetic recording medium having a magnetic layer formed on a substrate with an underlayer interposed therebetween, wherein the underlayer is formed of a first underlayer on the substrate side and a second underlayer on the magnetic layer side. Wherein the first underlayer is substantially composed of a binary alloy having a body-centered cubic structure having an equilibrium diagram of a solid solution system,
An in-plane magnetic recording medium, wherein the underlayer is made of a binary alloy having a substantially body-centered cubic structure and having a non-percentage solid solution system equilibrium diagram. 2. The in-plane magnetic recording medium according to claim 1, wherein the first underlayer is Cr.
2. The longitudinal magnetic recording medium according to claim 1, wherein the longitudinal magnetic recording medium contains one element selected from the group consisting of V, Mo, and W. 3. The in-plane magnetic recording medium according to claim 1, wherein the second underlayer is Cr.
3. The longitudinal magnetic recording medium according to claim 1, wherein the longitudinal magnetic recording medium contains one element selected from the group consisting of Ti, Ta, Nb, and Zr. 4. 4. A first underlayer of the longitudinal magnetic recording medium is composed of an alloy having a substantially body-centered cubic structure composed of three kinds of elements, and a binary system equilibrium diagram composed of a combination of the above elements is completely formed. 2. The in-plane magnetic recording medium according to claim 1, wherein the medium is a solid solution type. 5. The binary equilibrium diagram of the longitudinal magnetic recording medium, wherein the second underlayer is made of an alloy having a body-centered cubic structure composed of at least three or more elements, and a combination of the elements. 5. The in-plane magnetic recording medium according to claim 1, wherein at least one of the combinations is a non-percentage solid solution system. 6. The in-plane magnetic recording medium according to claim 1, wherein the first underlayer is Cr.
6. The longitudinal magnetic recording medium according to claim 4, wherein the longitudinal magnetic recording medium contains two types of elements selected from the group consisting of V, Mo, and W. 5. 7. The in-plane magnetic recording medium according to claim 1, wherein the second underlayer is Cr.
As a main component, and contains one type of element selected from the group consisting of Ti, Ta, Nb, and Zr.
7. The longitudinal magnetic recording medium according to claim 6, wherein the medium contains one kind of element selected from the group consisting of Si and Ge. 8. The in-plane magnetic recording medium according to claim 1, further comprising a substantially amorphous pre-coat layer between the substrate and the first underlayer of the in-plane magnetic recording medium. Magnetic recording medium. 9. The longitudinal magnetic recording medium according to claim 1, wherein a thickness of the first underlayer of the longitudinal magnetic recording medium is 3 nm or more and 10 nm or less. 10. A longitudinal magnetic recording medium having a magnetic layer formed on a substrate via an underlayer, a drive unit for driving the medium in a recording direction, a magnetic head comprising a recording unit and a reproducing unit,
A magnetic storage device comprising: means for moving the magnetic head relative to the longitudinal magnetic recording medium; and recording / reproducing signal processing means for reproducing a signal input from the magnetic head and an output signal from the magnetic head. 10. The longitudinal magnetic recording medium is constituted by the longitudinal magnetic recording medium according to claim 1, and a reproducing section of the magnetic head is constituted by a magnetoresistive magnetic head. Magnetic storage device. 11. A magneto-resistance effect type magnetic head is arranged between a plurality of conductive magnetic layers which generate a large resistance change by their magnetization directions relatively changing by an external magnetic field. 11. The magnetic storage device according to claim 10, wherein the magnetic storage device is constituted by a magnetoresistive sensor including a conductive nonmagnetic layer formed.