JP2983492B2 - Stack of antiferromagnetic layer and magnetic layer and magnetic head using the stack - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated body of an antiferromagnetic layer and a magnetic layer having excellent characteristics, and a magnetic head and a magnetic recording / reproducing apparatus using the same.

[0002]

2. Description of the Related Art With the increase in density of magnetic recording, a magnetoresistive head has begun to be used as a reproducing magnetic head. Materials showing high magnetoresistance are described in Physical Review B, Vol. 43, No. 1, 1297 by Dieny et al.
"Giant Magneto-resistance" on page 1300
A multilayer film in which two magnetic layers are separated by a non-magnetic layer and an exchange bias magnetic field from an antiferromagnetic layer is applied to one of the magnetic layers as in "Soft Ferromagnetic Multilayers" has been devised. Further, the number of magnetic layers of the above-mentioned multilayer film is increased to three layers,
The multi-layered film whose sensitivity has been improved is described in "The Giant Magnetoresistance of a Spin-Valve Stacked Film Using NiO Antiferromagnetic Film" in Journal of the Japan Society of Applied Magnetics, Vol. 18, pages 355-359, by Hoshiya et al.
It is described in.

As the material for the antiferromagnetic layer used for the above-mentioned purpose, a material capable of applying a high exchange bias magnetic field to the magnetic layer is desired. As a candidate for this antiferromagnetic layer material, Hosh
Japanese Journal of Applied Physics by ino et al.,
Vol. 35, No. 2A, pp. 607-612, “Exchan
ge Coupling between Antiferromagnetic Mn-Ir andFer
romagnetic Ni-Fe Layers ". According to this paper, the Ir composition is 20 to 30 at.
%, A relatively high exchange bias field is applied to the magnetic layer.

[0004]

In the above-mentioned laminated body of the antiferromagnetic layer and the magnetic layer, it is preferable that the exchange bias magnetic field as high as possible is applied to the magnetic layer. In particular, in a spin valve multilayer film including three magnetic layers, the crystal orientation control layer, the crystal structure control layer, the Mn-Ir
An antiferromagnetic layer made of a system alloy and a magnetic layer are stacked in this order. When a magnetic layer is laminated on such an antiferromagnetic layer, the crystal orientation of the Mn-Ir-based alloy layer deteriorates with the growth of the antiferromagnetic layer made of a Mn-Ir-based alloy, and the The crystal structure of the portion of the Mn-Ir-based alloy layer in contact with the layer no longer has a face-centered cubic structure. For this reason, at the uppermost part of the Mn-Ir-based alloy layer, the Mn-Ir-based alloy layer does not exhibit antiferromagnetism, and no exchange bias magnetic field is applied to the magnetic layer in contact with the portion.

SUMMARY OF THE INVENTION The present invention has been made in view of a problem in a laminated body of an Mn-Ir-based alloy antiferromagnetic layer and a magnetic layer. It is an object of the present invention to provide a means capable of applying a strong exchange bias magnetic field from an antiferromagnetic layer to a magnetic layer in a structure in which are stacked.

[0006]

Means for Solving the Problems The present inventors have proposed Mn-I
With the growth of the antiferromagnetic layer made of the r-based alloy, Mn-I
In the process of pursuing the cause of the deterioration of the crystal orientation of the r-based alloy layer, focusing on the large difference in the lattice constant between the crystal structure control layer and the Mn-Ir-based alloy layer, the results of intensive research,
A lattice matching layer having a face-centered cubic structure is provided between the crystal structure control layer and an antiferromagnetic layer made of a Mn-Ir-based alloy,
By setting the lattice constant of the lattice matching layer to a value between the lattice constant of the crystal structure control layer and the lattice constant of the Mn-Ir-based alloy layer, the crystal orientation of the Mn-Ir-based alloy antiferromagnetic layer is improved. The present inventors have found that a portion in contact with the magnetic layer does not deteriorate and has antiferromagnetism, and have completed the present invention.

[0007] That is, the laminate of the present invention comprises:
Crystal orientation control layer, crystal structure control layer, lattice matching layer, Mn
An antiferromagnetic layer made of an Ir-based alloy, and a magnetic layer, which are stacked in this order, wherein the crystal orientation control layer is made of an alloy containing a Group IVa or Va group element or a group IVa or Va group element of the periodic table as a main component. And a crystal structure control layer, a lattice matching layer and M
The antiferromagnetic layer made of the n-Ir alloy has a face-centered cubic structure, and the lattice constant of the lattice matching layer is the lattice constant of the crystal structure control layer and the lattice constant of the antiferromagnetic layer made of the Mn-Ir alloy. It is characterized by being between.

Here, when the lattice matching layer is made of an antiferromagnetic material, the thickness of the entire multilayer film can be reduced. For this purpose, it is preferable to use an Fe-Mn alloy as the lattice matching layer. The blocking temperature of the Mn-Ir alloy antiferromagnetic material is about 250 ° C, and the blocking temperature of the Fe-Mn alloy antiferromagnetic material is about 150 ° C. The exchange bias magnetic field applied from the antiferromagnetic layer to the magnetic layer decreases linearly with increasing temperature. Therefore, it is more advantageous to use a Mn-In alloy antiferromagnetic material than a Fe-Mn alloy antiferromagnetic material as the antiferromagnetic layer in contact with the magnetic layer because the degree of room for temperature is increased.

A multilayer film in which a non-magnetic layer, a magnetic layer, a non-magnetic layer, a magnetic layer, and an antiferromagnetic layer made of a Mn-Ir-based alloy are laminated in this order on the laminate has a high magnetoresistance change. Since it shows the ratio, it is suitable as a magnetoresistive magnetic head for a magnetic recording / reproducing apparatus.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. Example 1 A multilayer film whose sectional structure is schematically shown in FIG. 1 was formed. As the substrate 11, a single crystal of Si (100) was used.
As the crystal orientation control layer 12, a 5 nm-thick Hf
Was used. As the crystal structure control layer 13, Cu having a thickness of 3 nm was used. Fe-40a is used as the lattice matching layer 14.
A t% Mn alloy was used. As the antiferromagnetic layer 15, Mn
A -22 at% Ir alloy was used. As the magnetic layer 16,
A Ni-20 at% Fe layer having a thickness of 5 nm was used. For the protective layer 17, Hf having a thickness of 5 nm was used. In this embodiment,
The total thickness of the lattice matching layer 14 and the antiferromagnetic layer 15 is 10 n
m, and the thickness of each layer was changed.

An ion beam sputtering method was used for producing a multilayer film. The ultimate vacuum degree is 8 × 10 ⁻⁵ Pa, and the Ar pressure during sputtering is 0.02 Pa. The sputtering conditions at the time of forming the Hf layer and the Fe—Mn layer were as follows: acceleration voltage of ion gun: 300 V, ion current: 60 mA, N
The sputtering conditions for forming the i-Fe layer were an acceleration voltage of an ion gun of 300 V and an ion current of 40 mA. M
The sputtering conditions for forming the n-Ir alloy layer were an acceleration voltage of an ion gun of 600 V and an ion current of 60 mA.

FIG. 2 shows the relationship between the thickness of the lattice matching layer 14 made of an Fe—Mn alloy and the X-ray diffraction intensity of the (111) plane of the Mn—Ir alloy antiferromagnetic layer 15. Mn-I
The X-ray diffraction intensity of the r antiferromagnetic layer is 1 n
It is converted to around m. As shown in the figure, when the thickness of the lattice matching layer is 0 nm, that is, when the lattice matching layer is not used, the X-ray diffraction intensity is low. This indicates that the (111) orientation of the Mn-Ir antiferromagnetic layer becomes weaker with the growth of the Mn-Ir antiferromagnetic layer.

On the other hand, when a lattice matching layer made of an Fe-Mn alloy is formed between the Mn-Ir antiferromagnetic layer and the crystal structure control layer, X / nm of the Mn-Ir antiferromagnetic layer can be improved. The line diffraction intensity increases. Also, if the lattice matching layer thickness is 1
The X-ray diffraction intensity is substantially constant even when the thickness is larger than nm. This is because, when a lattice matching layer made of an Fe-Mn alloy is formed between the Mn-Ir antiferromagnetic layer and the crystal structure control layer, the crystal orientation that has occurred with the growth of the Mn-Ir antiferromagnetic layer This indicates that the deterioration of the properties has been prevented.

Next, the relationship between the thickness of the lattice matching layer 14 made of an Fe—Mn alloy and the exchange bias magnetic field applied to the magnetic layer 16 was examined. In this experiment, two layers were used.
Heat treatment is performed at 50 ° C. in a magnetic field of 80 kA / m for 15 minutes. As shown in FIG. 3, when the thickness of the lattice matching layer is 0 nm, that is, when the lattice matching layer is not used, the exchange bias magnetic field applied to the magnetic layer is very low. This is because Mn-I
This is because the (111) orientation of the Mn-Ir antiferromagnetic layer becomes weaker with the growth of the r antiferromagnetic layer, and the Mn-Ir-based alloy does not have a face-centered cubic structure and does not exhibit antiferromagnetism at room temperature. .

On the other hand, when a lattice matching layer made of an Fe-Mn alloy is formed between the Mn-Ir antiferromagnetic layer and the crystal structure control layer, the exchange bias magnetic field applied to the magnetic layer increases. . This is because the deterioration of the crystal orientation which occurred with the growth of the Mn-Ir antiferromagnetic layer is prevented, and the Mn-Ir
This is because the Ir-based alloy retains the face-centered cubic structure and thus does not lose its antiferromagnetism.

As described above, when a lattice matching layer made of an Fe-Mn alloy is formed between the Mn-Ir antiferromagnetic layer and the crystal structure control layer, the lattice matching layer is formed with the growth of the Mn-Ir antiferromagnetic layer. As a result, the deterioration of the crystal orientation is prevented, and the exchange bias magnetic field applied to the magnetic layer is increased. This is because the lattice constant of the lattice matching layer is the lattice constant of the crystal structure control layer and Mn.
-Ir is between the lattice constants of the antiferromagnetic layer,
This is probably because the n-Ir antiferromagnetic layer was grown smoothly. Therefore, the material of the lattice matching layer has a face-centered cubic structure, and its lattice constant needs to be between the lattice constant of the crystal structure control layer and the lattice constant of the Mn-Ir antiferromagnetic layer.

Incidentally, the thickness of the antiferromagnetic layer needs to be not less than a certain critical layer thickness. Therefore, when a material having antiferromagnetism is used for the lattice matching layer, M
The thickness of the n-Ir antiferromagnetic layer can be reduced. When the laminate is used as a magnetoresistive material for a magnetoresistive head, it is preferable that the thickness of the magnetoresistive material be small because the magnetic head is arranged within a narrow shield interval. Therefore, it is preferable to use an antiferromagnetic material as the lattice matching layer.

In this embodiment, as the crystal orientation control layer,
Hf was used, but element IVa or V in the periodic table was used.
Similar results can be obtained by using a group a element.
In addition, an alloy material containing a Group IVa or Va element in the periodic table as a main component can also be used. In this embodiment, Cu is used as the crystal structure control layer. However, similar results can be obtained by using another metal material having a face-centered cubic structure.

As a conventional example of laminating two kinds of antiferromagnetic materials, there is one described in Japanese Patent Application Laid-Open No. 9-50612. However, when the antiferromagnetic layer is formed on the magnetic layer, the difference in characteristics between the two types of antiferromagnetic layer material is used. When a layer is formed, it differs from the stacking performed for facilitating the growth of the antiferromagnetic layer in structure and effect.

Example 2 A dual spin valve multilayer film including the multilayer film described in Example 1 was formed. FIG. 4 schematically shows the multilayer structure of the multilayer film. In FIG. 4, the substrate 31
Used was a Si (100) single crystal. As the crystal orientation control layer 32, Hf having a thickness of 5 nm was used. As the crystal structure control layer 33, Cu having a thickness of 5 nm was used. As the lattice matching layer 34, Fe-40 at% of thickness 2 nm
A Mn-based alloy was used. The antiferromagnetic layer 35 has a thickness of 8
nm Mn-22 at% Ir alloy was used. Magnetic layer 3
6 and 40 are 3 nm thick Ni-16 at% Fe.
A -18 at% Co alloy was used. As the nonmagnetic layers 37 and 39, Cu having a thickness of 2.5 nm was used. The magnetic layer 38 is made of Ni-16 at% Fe-18 at 5 nm thick.
% Co alloy was used. The antiferromagnetic layer 41 has a thickness of 1
A 0 nm Mn-22 at% Ir alloy was used.

The multilayer film having the above structure exhibited a magnetoresistance ratio of 6.5%. This is because a high exchange bias magnetic field is applied to the magnetic layer in contact with the antiferromagnetic layer. For comparison, a dual spin-valve multilayer film different from that of Example 2 was produced only in that the antiferromagnetic layer 35 was directly laminated on the crystal structure control layer 33 without providing the lattice matching layer 34. The magnetoresistance ratio of the film was 3.0%. This is because the exchange bias magnetic field is not applied from the antiferromagnetic layer 35 to the magnetic layer 36, so that the magnetic layer 36 rotates at the same time as the magnetic layer 38, and no magnetic resistance is generated in the portion sandwiching the nonmagnetic layer 37. .

Example 3 A magnetic head was manufactured using the multilayer film described in Example 2. FIG. 5 shows the structure of the magnetic head. FIG. 5 is a perspective view when a part of the recording / reproducing separation type head is cut. The portion where the above-mentioned multilayer film 51 is sandwiched between the shield layers 52 and 53 functions as a reproducing head, and the portions of the lower magnetic pole 55 and the upper magnetic pole 56 which sandwich the coil 54 function as a recording head. The electrode 58 has a Cr / Cu /
A material having a multilayer structure of Cr was used.

Hereinafter, a method of manufacturing the head will be described. A
A sintered body mainly composed of l ₂ O ₃ .TiC was used as a substrate 57 for the slider. A Ni-Fe alloy formed by a sputtering method was used for the shield layer and the recording magnetic pole. The thickness of each magnetic film was as follows. Upper and lower shield layers 52, 53
Is 1.0 μm, the upper and lower magnetic poles 55 and 56 are 3.0 μm, and a gap material between the layers is formed by sputtering.
l ₂ O ₃ was used. The thickness of the gap layer is 0.2 μm between the shield layer and the magnetoresistive element, and 0.4 μm between the recording magnetic poles.
μm. Further, the distance between the reproducing head and the recording head was about 4 μm, and this gap was also formed of Al ₂ O ₃ . Cu having a thickness of 3 μm was used for the coil 54.

When recording and reproduction were performed with the magnetic head having the above-described structure, a reproduction output 6.2 times higher than that of a magnetic head using a Ni—Fe single layer film was obtained. This is probably because the magnetic head of the present invention used a multilayer film exhibiting a high magnetoresistance effect.

Example 4 A magnetic recording / reproducing apparatus incorporating the magnetic head of the present invention described in Example 3 was manufactured. FIG. 6A is a plan view of the magnetic recording / reproducing apparatus, and FIG.
As schematically shown in the sectional view taken along the line AA 'of FIG.
And a magnetic recording / reproducing apparatus having a well-known configuration including a magnetic head 63, a driving unit 64 thereof, and a recording / reproducing signal processing system 65 connected to the magnetic head 63.

The magnetic recording medium 61 rotated by the magnetic recording medium drive 62 has a Co-
A material composed of a Ni-Pt-Ta alloy was used. The track width of the magnetic head 63 held by the magnetic head driving unit 64 was 1.5 μm. According to the present embodiment, a high-performance magnetic recording / reproducing apparatus which does not impose a load on the recording / reproducing signal processing system 65 was obtained because the reproducing output of the magnetoresistive element in the magnetic head 63 is high.

[0027]

As described above, Mn-Ir is formed under the magnetic layer.
When forming a system alloy antiferromagnetic layer, by providing a lattice matching layer between the crystal structure control layer and the Mn-Ir system alloy antiferromagnetic layer, the crystal orientation of the Mn-Ir system alloy antiferromagnetic layer is provided. The portion in contact with the magnetic layer has antiferromagnetism without deterioration in properties. By applying this laminate to a dual spin valve, a magnetoresistive film having a high magnetoresistance ratio can be obtained. This magnetoresistive film is suitable for a magnetoresistive magnetic head of a magnetic recording / reproducing apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing the structure of a multilayer film in which an antiferromagnetic layer and a magnetic layer are stacked.

FIG. 2 is a graph showing the relationship between the thickness of the lattice matching layer and the X-ray diffraction intensity of the (111) plane of the Mn—Ir-based alloy antiferromagnetic layer.

FIG. 3 is a graph showing a relationship between a thickness of a lattice matching layer and an exchange bias magnetic field applied to a magnetic layer.

FIG. 4 is a schematic sectional view showing a laminated structure of a dual spin valve multilayer film using the multilayer film of the present invention.

FIG. 5 is a perspective view showing the structure of a magnetic head.

FIG. 6 is a schematic diagram of a magnetic disk drive.

[Explanation of symbols]

11, 31 ... substrate, 12, 32 ... crystalline orientation control layer,
13, 33: crystal structure control layer, 14, 34: lattice matching layer, 15, 35, 41: Mn-Ir alloy antiferromagnetic layer,
16, 36, 38, 40: magnetic layer, 17: protective layer, 3
7, 39: non-magnetic layer, 51: multilayer film, 52, 53 ...
Magnetic layer, 54 ... coil, 55 ... lower magnetic pole, 56 ... upper magnetic pole, 57 ... substrate, 58 ... electrode, 61 ... magnetic recording medium, 6
2: magnetic recording medium driving unit, 63: magnetic head, 64: magnetic head driving unit, 65: recording / reproducing signal processing system

Claims (5)

(57) [Claims] 1. A crystal orientation control layer comprising: a crystal orientation control layer, a crystal structure control layer, a lattice matching layer, an antiferromagnetic layer made of a Mn—Ir-based alloy, and a magnetic layer. Is group IVa or Va in the periodic table
A crystal structure control layer, a lattice matching layer, and an alloy containing a group IV element or an alloy mainly containing a group IVa or group Va element.
The antiferromagnetic layer made of an Ir-based alloy has a face-centered cubic structure, and the lattice constant of the lattice matching layer is the lattice constant of the crystal structure control layer and the lattice constant of the antiferromagnetic layer made of a Mn-Ir-based alloy And a laminate. 2. The laminate according to claim 1, wherein the lattice matching layer is an antiferromagnetic material. 3. The laminate according to claim 1, wherein the lattice matching layer is an Fe—Mn alloy. 4. A non-magnetic layer, a magnetic layer, a non-magnetic layer, a magnetic layer, and an antiferromagnetic layer made of a Mn-Ir-based alloy are sequentially laminated on the laminate according to claim 1, 2 or 3. A magnetic head characterized in that at least a part of a multilayer film is used. 5. A magnetic recording / reproducing apparatus comprising the magnetic head according to claim 4.