JPH10275722A - Switching coupling film, magnetoresistive effect element and magnetic head using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance corrosion resistance and specific resistance by producing magnetic switching coupling in the interface between an antiferromagnetic material film mainly composed of the crystal phase of body-centered cubic structure, composed of Cr and any one of Al, Ga and In, 3b-group elements from a periodic table, and a ferromagnetic material film containing one or more of Fe, Ni and Co. SOLUTION: An AMR ferromagnetic material film 23 is laminated on a ferromagnetic material film 21 with an electrical insulating layer 22 in-between. A vertical bias ferromagnetic material film 24, an antiferromagnetic material film 25, and a conductive layer 26 are laminated in this order on both sides of the laminate. The antiferromagnetic material film 25 is mainly composed of the crystal phase of body- centered cubic structure, composed of Cr and any one of Al, Ga and In, 3b-group elements from a periodic table. The vertical bias ferromagnetic material film 24 contains one or more of Fe, Ni and Co. Thus magnetic switching coupling is produced in the interface between the antiferromagnetic material film 25 and the vertical bias ferromagnetic material film 24. As a result, characteristics of excellent corrosion resistance and high specific resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exchange coupling film used for reading magnetic information of a magnetic recording medium by utilizing a magnetoresistance effect based on magnetic exchange coupling, and a magnetoresistance effect element using the same. And about the magnetic head.

[0002]

2. Description of the Related Art Conventional magnetoresistive read heads (MR heads) include an AMR (Anisotropic Magnetoresistance) head using an anisotropic magnetoresistance effect phenomenon and a GMR using a spin-dependent scattering phenomenon of conduction electrons.
(Giant Magnetoresistance) Head is an example of a GMR head that has a high external magnetic field and a high magnetoresistance effect.
An in-Valve head (hereinafter abbreviated as a spin valve head) is shown in U.S. Pat. No. 5,159,513.

FIGS. 1 and 2 are schematic views of an AMR head element structure. For optimal operation of AMR head, AMR
Two bias magnetic fields are required for the AMR ferromagnetic film 3 (AMR material layer) exhibiting the effect. One bias magnetic field is for making the resistance change of the AMR material linearly respond to the magnetic flux from the magnetic medium, and this bias magnetic field is perpendicular to the plane of the magnetic medium (the Z direction in the figure), and AM
It is parallel to the film surface of the R ferromagnetic film 3. Usually, this bias magnetic field is called a lateral bias, and the AMR ferromagnetic film 3
Can be obtained by arranging a soft magnetic material film 1 formed via an electric insulating layer 2 in the vicinity of, and flowing a detection current from the conductive layer 5 to the AMR head element. The other bias magnetic field, usually called the longitudinal bias magnetic field,
The voltage is applied in parallel to the film surface of the MR ferromagnetic film 3 (X direction in the figure). The purpose of the longitudinal bias magnetic field is to suppress Barkhausen noise caused by the AMR ferromagnetic film 3 forming a large number of magnetic domains, that is, to achieve a smooth resistance change from the magnetic medium to the magnetic flux without noise. It is.

In order to suppress Barkhausen noise, it is necessary to form the AMR ferromagnetic film 3 into a single magnetic domain.
There are two methods for applying a vertical bias for this purpose. One is to arrange the magnet layers 6 on both sides of the AMR ferromagnetic film 3 (on both sides in the width direction of the ferromagnetic film 3 formed to have a width corresponding to the track width in FIG. 2) as shown in FIG. Another method is to use the leakage magnetic flux from the magnet layer 6, and another method is to use an antiferromagnetic material disposed on the AMR ferromagnetic film 3 with a gap corresponding to the track width as shown in FIG. In this method, an exchange anisotropic magnetic field generated at the contact interface between the body films 4 and 4 and the ferromagnetic film 3 is used.

On the other hand, as shown in FIG. 3 or FIG. 4, for the optimum operation of the spin valve head, the sandwich structure of the free ferromagnetic film 7 / non-magnetic intermediate layer 8 / pinned ferromagnetic film 9 A bias is applied to the free ferromagnetic film 7 in the track direction (X direction in the figure) and the magnetization is directed in the track direction in a state where the magnetic domain is made into a single magnetic domain. That is, it is necessary to apply a bias in a direction orthogonal to the magnetization direction of the free ferromagnetic film 7 and to direct the free ferromagnetic film 7 in the Z direction in FIG. The magnetization direction of the pinned ferromagnetic film 9 must not change due to the magnetic flux from the magnetic medium (the Z direction in the figure), and the magnetization direction of the free ferromagnetic film 7 By changing the magnetization direction within a range of 90 ± θ degrees, a linear response of the magnetoresistance effect can be obtained.

The magnetization direction of the pinned ferromagnetic film 9 is shown by Z in FIG.
To fix in the direction, a relatively large bias magnetic field is required, and the larger the bias magnetic field, the better. In order to overcome the demagnetizing field in the Z direction in the figure and prevent the magnetization direction from fluctuating due to the magnetic flux from the magnetic medium, a bias magnetic field of at least 100 Oe is required. As a method for obtaining the bias magnetic field, a method utilizing an exchange anisotropic magnetic field generated by bringing the antiferromagnetic film 10 into contact with the pinned ferromagnetic film 9 as shown in FIG. is there.

The bias applied to the free ferromagnetic film 7 is to ensure linear response and to suppress Barkhausen noise generated by forming a large number of magnetic domains, and is the same as the longitudinal bias in the AMR head. 3, a method of arranging the magnet layers 11 on both sides of the free ferromagnetic film 7 as shown in FIG. 3 and utilizing magnetic flux leakage from the magnet layers 11 and a method of using the anti-ferromagnetic material as shown in FIG. A method utilizing an exchange anisotropic magnetic field generated at a contact interface with the film 13 is usually used. As described above, the longitudinal bias of the AMR head,
Alternatively, the linear response is improved by utilizing the exchange anisotropic magnetic field generated at the contact interface with the antiferromagnetic film for the bias of the pinned ferromagnetic film and the bias of the free ferromagnetic film of the spin valve head. It is possible to realize a magnetoresistive head in which Barkhausen noise is suppressed.

[0008]

The exchange anisotropic magnetic field is a phenomenon caused by an exchange interaction between two magnetic moments at a contact interface between a ferromagnetic film and an antiferromagnetic film. A FeMn film is well known as an antiferromagnetic film that generates an exchange anisotropic magnetic field of a body film, for example, a NiFe film. However, the FeMn film has remarkably poor corrosion resistance, and there is a problem that corrosion occurs during the magnetic head manufacturing process and during the operation of the magnetic head, which greatly deteriorates the exchange anisotropic magnetic field and damages the magnetic medium. . It is known that the temperature near the FeMn film during the operation of the magnetic head rises to about 120 ° C. due to heat generated by the detected current.
The exchange anisotropic magnetic field due to the FeMn film is sensitive to temperature change, and decreases almost linearly with temperature until disappears at a temperature of about 150 ° C. (blocking temperature: Tb). Therefore, there is a problem that a stable exchange anisotropic magnetic field cannot be obtained.

Further, as an invention in which the corrosion resistance and the blocking temperature of the FeMn film are improved, see, for example, Japanese Patent Application Laid-Open No. 6-76247.
Having a face-centered tetragonal structure shown in
Although there is an alloy or a NiMnCr alloy, the corrosion resistance of the NiMn film is better than the corrosion resistance of the FeMn film, but is insufficient for practical use. The NiMnCr film is an alloy to which Cr is added in order to improve the corrosion resistance of the NiMn film. However, there is a problem that the addition of Cr improves the corrosion resistance but reduces the magnitude of the exchange anisotropic magnetic field.

The present invention has been made in view of the above circumstances, and has a structure capable of causing magnetic exchange coupling between an antiferromagnetic film and a ferromagnetic film. To provide an excellent exchange-coupling film that has a structure that uses a completely new product, and has excellent corrosion resistance and high specific resistance, and to provide a magnetoresistive element and a magnetic head equipped with this exchange-coupling film. Aim.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has been made to solve the above-mentioned problems by using Cr and Al and G elements of Group 3b of the periodic table.
an antiferromagnetic film mainly composed of a crystal phase having a body-centered cubic structure composed of at least one element M of a and In;
e, a ferromagnetic film containing at least one of Ni and Co is laminated so as to be in contact with each other, and magnetic exchange coupling is generated at an interface between the antiferromagnetic film and the ferromagnetic film. It becomes.

According to the present invention, in order to solve the above-mentioned problems, the antiferromagnetic film is preferentially oriented to one of {100} and {110}. Further, it is preferable that the crystal grain diameter D of the antiferromagnetic film is smaller than the domain wall width δ _AF of the antiferromagnetic film. Furthermore, it is preferable that the crystal grain size D of the antiferromagnetic film is set to D ≦ 300 °.
In order to solve the above-described problems, the present invention is configured such that the exchange-coupling film is formed on a base material via a base film, and the base film is
It is made of one or more of MgO, AlN, Ta, ZnO, Si, and Fe-Ni alloy. Further, in order to solve the above-mentioned problem, the present invention is characterized in that the spontaneous corrosion potential of the antiferromagnetic film shows a positive value with respect to a saturated calomel electrode. According to the present invention, in order to solve the above-mentioned problem, the thickness of the antiferromagnetic film is set to 300 ° or more. In the present invention, it is preferable that the specific resistance of the antiferromagnetic film be 200 μΩcm or more. Al
In the case of an antiferromagnetic film to which is added, the specific resistance is 500 μΩ.
cm or more.

In the present invention, the antiferromagnetic film is represented, for example, by the following composition formula. Cr _x Al _y, where x and y indicating the composition ratio are atomic%, and 60 ≦ x ≦ 9.
0, 10 ≦ y ≦ 40. Further, in the present invention, it is preferable that x is in the range of 65 ≦ x ≦ 80 and y is in the range of 20 ≦ y ≦ 35. If the Al content is less than 10 atomic%, the exchange anisotropic magnetic field (H _ex ) deteriorates (almost 0).
And is not preferred. If the content of Al exceeds 40 atomic%, the bcc phase does not precipitate, and the exchange anisotropic magnetic field also deteriorates, which is not preferable. Even more preferably, the content of Al is in the range of 20 to 35 atomic%, whereby a high exchange anisotropic magnetic field can be obtained. In the present invention, the antiferromagnetic film may be, for example, one represented by the following composition formula. Cr _x Ga _z here, x indicating the composition ratio, z is in atomic%, 85 ≦ x ≦ 9
5, 5 ≦ z ≦ 15. Ga is 5 atomic% to 15
Within the range of atomic%, a high exchange anisotropic magnetic field and a high specific resistance can be obtained. Further, in the present invention, the antiferromagnetic material film may be represented by, for example, the following composition formula. Cr _x an In _w here, x indicating the composition ratio, w is, 85 ≦ x ≦ 95 in atomic percent,
The range is 5 ≦ w ≦ 15. When In is in the range of 5 atomic% to 15 atomic%, a high exchange anisotropic magnetic field and a high specific resistance can be obtained.

In order to solve the above-mentioned problems, the present invention provides C
r, and an antiferromagnetic film having a body-centered cubic structure composed of at least one element M of Al, Ga, and In of Group 3b elements of the periodic table, and at least one or more of Fe, Ni, and Co The ferromagnetic films are laminated so as to be in contact with each other, and magnetic exchange coupling is generated at an interface between the antiferromagnetic film and the ferromagnetic film to apply a longitudinal bias to the ferromagnetic film. It is formed of a soft magnetic material film laminated on a coupling film with at least a non-magnetic film interposed therebetween and applying a lateral bias to the ferromagnetic film. In order to solve the above-mentioned problems, the present invention provides an antiferromagnetic film having a body-centered cubic structure composed of Cr and at least one element M of Al, Ga, and In of Group 3b of the periodic table; , Ni, Co are laminated so as to be in contact with each other, and a magnetic exchange coupling is generated at an interface between the antiferromagnetic film and the ferromagnetic film to form the magnetic film. An exchange coupling film in which a ferromagnetic film is pinned as a magnetic film, and a ferromagnetic film in which a single magnetic domain is formed through at least a nonmagnetic film are laminated.

In order to solve the above-mentioned problems, the present invention provides a C
r, and an antiferromagnetic film having a body-centered cubic structure composed of at least one element M of Al, Ga, and In of Group 3b elements of the periodic table, and at least one or more of Fe, Ni, and Co The ferromagnetic films are laminated so as to be in contact with each other, and magnetic exchange coupling is generated at an interface between the antiferromagnetic film and the ferromagnetic film to apply a longitudinal bias to the ferromagnetic film. A coupling film, a magnetoresistive element that is stacked with at least a non-magnetic film interposed therebetween and that is made of a soft magnetic material film that applies a lateral bias to the ferromagnetic film, and that reads magnetic recording recorded on a magnetic recording medium; And a magnetic core formed of at least a soft magnetic material forming a magnetic circuit, a magnetic gap and a coil, and an inductive head for writing magnetic recording on a magnetic recording medium. In order to solve the above-mentioned problems, the present invention provides an antiferromagnetic film having a body-centered cubic structure composed of Cr and at least one element M of Al, Ga, and In of Group 3b of the periodic table; , Ni, C
and a ferromagnetic film containing at least one of the above ferromagnetic films, and magnetically exchange-coupled to the interface between the antiferromagnetic film and the ferromagnetic film to form the ferromagnetic film. A magnetoresistive element in which an exchange-coupling film whose film is a pinned magnetic film, and a ferromagnetic film that has been made into a single magnetic domain via at least a nonmagnetic film, and a soft magnetic material that forms at least a magnetic circuit And an inductive head for writing magnetic recording on a magnetic recording medium.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The exchange-coupling film according to the present invention is basically composed of Cr, Al and G of Group 3b elements of the periodic table.
a body-centered cubic antiferromagnetic film composed of at least one element M of a and In and a ferromagnetic film containing at least one of Fe, Ni, and Co so as to be in contact with each other The magnetic exchange coupling is generated at the interface between the antiferromagnetic film and the ferromagnetic film. More specifically, it is represented by a composition formula of Cr- (Al, Ga, In).

In the above structure, the antiferromagnetic film is represented by, for example, the following composition formula. Cr _x Al _y, where x and y indicating the composition ratio are atomic%, and 60 ≦ x ≦ 9.
0, 10 ≦ y ≦ 40. In addition, x is 65 ≦
It is preferable that x ≦ 80 and y be in the range of 20 ≦ y ≦ 35. If the content of Al is less than 10 atomic%, the exchange anisotropic magnetic field ( _Hex ) deteriorates (almost 0), which is not preferable.
If the content of Al exceeds 40 atomic%, the bcc phase does not precipitate, and the exchange anisotropic magnetic field also deteriorates, which is not preferable. Even more preferably in these ranges, Al
Is contained in an amount of 20 to 35 atomic%, whereby a high exchange anisotropic magnetic field can be obtained. In an exchange-coupling film having a CrAl-based antiferromagnetic material film, the Neel temperature becomes maximum when the Al concentration is around 30 atomic%. In the above structure, the antiferromagnetic film may be represented by the following composition formula, for example. Cr _x Ga _z here, x indicating the composition ratio, z is in atomic%, 85 ≦ x ≦ 9
5, 5 ≦ z ≦ 15. Ga is 5 atomic% to 15
Within the range of atomic%, a high exchange anisotropic magnetic field and a high specific resistance can be obtained. In an exchange-coupling film having a CrGa-based antiferromagnetic film, the concentration of Ga is 15 atomic%.
In the vicinity, the Neel temperature becomes maximum. In the above structure, the antiferromagnetic film may be represented by the following composition formula, for example. Cr _x an In _w here, x indicating the composition ratio, w is, in atomic%, 85 ≦ x ≦ 9
5, 5 ≦ w ≦ 15. In is 5 atomic% to 15
Within the range of atomic%, a high exchange anisotropic magnetic field and a high specific resistance can be obtained.

Since the structure as described above can be applied to the longitudinal bias in the AMR head shown in FIG. 1, in the structure of FIG. 1, the antiferromagnetic film 4 is made of Cr, Al of group 3b of the periodic table, Al, The ferromagnetic film 3 is composed of an alloy film containing at least one of Fe, Ni, and Co, which is composed of an alloy film having a body-centered cubic structure composed of at least one element M of Ga and In. I do. In addition, the structure as described above is shown in FIG.
3 can be applied to the longitudinal bias in the AMR head shown in FIG. In the structure shown in FIG. 23, an AMR ferromagnetic film 23 is laminated on a ferromagnetic film 21 via an electric insulating layer 22, and a longitudinal bias made of Fe—Ni or the like is provided on both sides of the laminated body. A ferromagnetic film 24, an antiferromagnetic film 25 within the composition range of the present invention, and a conductive layer 26 are sequentially laminated.
In the head, the anti-ferromagnetic film 25 divides the longitudinally biased ferromagnetic film 24 into a single magnetic domain in a direction indicated by an arrow (X direction) shown in FIG.
The R ferromagnetic film 23 can be made into a single magnetic domain in the direction of the arrow (X direction), so that the same effect as the magnet layer 6 in the AMR head having the structure shown in FIG. 2 can be achieved. In the structure shown in FIG.
5 is Cr and Al, Ga, In which are elements of Group 3b of the periodic table.
Is composed of an alloy film having a body-centered cubic structure composed of at least one of the elements M. 3 and 4, the antiferromagnetic film 10 or the antiferromagnetic film 1
3 is composed of an alloy film having a body-centered cubic structure composed of Cr and at least one element M of Al, Ga, and In of Group 3b elements of the periodic table, and a pinned ferromagnetic film 9
Alternatively, the free ferromagnetic film 7 is made of an alloy film containing at least one of Fe, Ni, and Co. With the above-described structure, the exchange coupling film of the present invention can be provided with a longitudinal bias applying structure in the AMR head shown in FIGS. 1 and 23, and a pinning bias of the pinning layer 9 in the spin valve head shown in FIG. The structure can be applied to all of the bias applying structure of the free ferromagnetic film 7 and the pinning bias structure of the pinned ferromagnetic film 9 shown in FIG.

Next, in the structure of the present invention, it is preferable that the antiferromagnetic film is preferentially oriented to either {100} or {110}. In addition, any one of these planes is oriented so as to emerge on the film surface, and in such an orientation state, a crystal axis having an azimuthal relationship perpendicular to the <100> axis or the <110> axis is randomly oriented in the film plane. Is more preferable. The exchange coupling film is usually formed on a substrate, but it is preferable that the exchange coupling film is formed sequentially after forming a base film on the substrate. MgO, A
It is possible to use one or more of 1N, Ta, ZnO, and Si. By forming these base films, the quality of the antiferromagnetic film or ferromagnetic film formed thereon is stabilized, and the crystal orientation can be controlled. Further, the antiferromagnetic film may have a spontaneous corrosion potential in 0.1 N sodium nitrite (Na ₂ SO ₃ .7H ₂ O) having a positive value (0 V or more) with respect to a saturated calomel electrode. Preferably, it is more than 0.1V.
In this respect, if the composition is as described above, a natural corrosion potential in such a range can be easily obtained. Further, the thickness of the antiferromagnetic film is preferably in the range of 300 ° or more.
If the film thickness is less than 300 °, the exchange bias magnetic field is undesirably reduced.

Next, the antiferromagnetic film having a specific resistance of 200 μΩcm or more can be easily obtained. Especially,
In the case of an antiferromagnetic film to which Al is added, a film having a specific resistance of 500 μΩcm or more can be easily obtained. When the specific resistance is high as described above, it is possible to prevent the detection current flowing through the spin-valve magnetoresistive element from flowing to the antiferromagnetic film. That is, there is an effect of minimizing the shunt of the current that does not contribute to the resistance change and increasing the resistance change rate of the element.

[0021]

[Embodiment] All films were deposited on RF (Radio Frequency) conveyor.
Performed by directional sputtering or DC sputtering
Was. The target is made of Cr on a target made of Al.
Using the one where the pellets are arranged, on a plurality of Si substrates,
100mm, 500mm, 900mm, 2000mm thick
Each Cr₈₁Al₁₉Film and Ni, each 50Å thick ₈₁
Fe₁₉X-ray diffraction of individual samples
The curve was measured. Note that the target is
In addition, Cr₇₀Al₃₀Duplex with Cr pellets placed on alloy
A combined target may be used. The results are shown in FIG.
You. As is clear from the results shown in FIG.
In each sample with a thickness of 00 °, around 2θ = 43.8 °
A peak of (110) was observed. Also, 900Å, 2
In the case of a sample of 2,000 mm, around 64.05 mm (20
The peak of 0) was observed. Therefore, in these samples
Body-centered cubic for samples 500-2000 mm thick
It was confirmed that the structure was shown. Note that in FIG.
The weak peak near 2θ = 70 ° is (10
0) peak, the surface of the Si substrate is (100) oriented
It indicates that.

FIG. 6 shows a comparison between the corrosion potentials of various known antiferromagnetic films and the antiferromagnetic film according to the present invention. These values make these materials 0.1N
It is a polarization curve when immersed in sodium nitrite (Na ₂ SO ₃ .7H ₂ O).
If it is V, those having a higher potential will have higher corrosion resistance. The Cr—Al antiferromagnetic film according to the present invention always has a positive corrosion potential of 0.1 V or more, whereas FeMn, NiMn, NiFe, NiM n
It is clear that any antiferromagnetic material film of Cr has a low corrosion potential and is more easily corroded than that of the composition system according to the present invention. In FIG. 6, the curve from the right indicates that the corrosion resistance is better.

FIG. 7 shows that a plurality of Si substrates have a thickness of 100
ＳｉSi underlayer is formed and Ni ₈₁ Fel with a thickness of 50Å
₁₉ and the membrane, forming a different thickness of the Cr ₈₁ Al ₁₉ film, showing the results of measuring the film thickness dependence of Cr ₈₁ Al ₁₉ film to the exchange anisotropic magnetic field (H _ex). From this figure, when a CrAl film is laminated on a NiFe film to form an exchange coupling film, it is preferable to increase the thickness of the CrAl film to some extent in order to obtain a high exchange anisotropic magnetic field ( _Hex ). It is clear that
Specifically, in order to obtain an exchange anisotropic magnetic field (H _ex ) of 300 ° or more, more specifically 20 or more, of the CrAl film, the thickness is preferably 700 ° to 2000 °. FIG.
It is a plurality of Si substrates, and Cr ₈₁ Al ₁₉ film of various thicknesses, thereby forming a Ni ₈₁ Fe ₁₉ film having a thickness of 50 Å, Cr ₈₁ Al ₁₉ for exchange anisotropic magnetic field (H _ex) film 3 shows the results of measuring the film thickness dependence of. From this figure, it can be seen that Ni
When a Fe film is laminated, a high exchange anisotropic magnetic field ( _Hex is 2
0 or more), it is clear that it is preferable to increase the thickness of the CrAl film to some extent. Specifically, the thickness of the CrAl film is preferably in the range of 300 to 1500, more preferably 300 to 1000. And

FIG. 9 shows a Cr70Al30 film formed on a Si substrate.
The film is then further coated with a 50 ° thick Ni ₈₁Fe₁₉Film
Of the exchange anisotropic magnetic field obtained with a different structure (without MgO)
Dependence on Al film thickness and Cr on Si substrate via MgO film
₇₀Al₃₀Film and Ni₈₁Fe₁₉Film-formed structure (MgO
The dependence of the exchange anisotropic magnetic field obtained in
Show. From the results shown in FIG. 9, it can be seen that there is no MgO film.
In the construction,₇₀Al₃₀Exchange anisotropy at 200Å
Although a magnetic field cannot be obtained, Cr₇₀Al₃₀200 膜厚
An exchange anisotropic magnetic field can be obtained from a thickness exceeding
Rises sharply and Cr ₇₀Al₃₀Smell more than 300mm thick
It can be seen that the exchange anisotropic magnetic field becomes 20 Oe or more.
You. In order to make the exchange anisotropic magnetic field 30 Oe or more,
Contains Cr₇₀Al_{Three 0}The thickness of the film ranges from 400 to 900 mm
It is clear that it is preferable to use Next, S
Cr on the underlayer on the i-substrate via MgO₇₀Al₃₀With membrane
Ni₈₁Fe ₁₉When adopting a structure for forming a film, Cr₇₀
Al₃₀When the thickness of the film exceeds 700 mm, the exchange anisotropic magnetic field
Is 20 Oe or more. Also, exchange anisotropic
In order to increase the inductive magnetic field to 30 Oe or more, Cr₇₀Al₃₀
The thickness of the film is preferably in the range of 900 to 1300 °.
It is also clear that it is. From the results shown in FIGS. 8 and 9,
Even if the composition of CrAl is slightly different, M
In any case using gO, a CrAl film
Good replacement by setting the thickness in the range of 300 to 1500 °
An anisotropic magnetic field could be obtained.

FIG. 10 shows an S-type substrate having a thickness of 100 ° on a Si substrate.
i layer forming the (100), Cr ₇₀ exchange anisotropic magnetic field obtained by the structure was deposited Ni ₈₁ Fe ₁₉ film having a thickness of 50Å on and its further deposited Cr ₇₀ Al ₃₀ film thereon This shows the dependence on the Al ₃₀ film thickness. From the results shown in FIG. 10, Cr ₇₀ Al ₃₀ value of the exchange anisotropic magnetic field from a thickness greater than the film thickness 200Å rises rapidly, the exchange anisotropic magnetic field in the Cr ₇₀ Al ₃₀ film thickness 300Å or 20 Oe or more It turns out that it becomes. Also,
In order to make the exchange anisotropic magnetic field 30 Oe or more, Cr
Preferably to a thickness of ₇₀ Al ₃₀ film and scope of 400~900Å It is also apparent.

FIG. 11 shows that Si (100 °) is formed on a Si substrate.
Is formed, and a Ni ₈₁ Fe ₁₉ film (tÅ) and Cr ₇₀ Al ₃₀
Film for samples by laminating (500 Å) and Ni ₈₁ Fe ₁₉ film (50 Å), measured exchange anisotropic magnetic field (H _ex), the antiferromagnetic film is a Cr ₇₀ Al ₃₀ film in the thickness direction of the grain The result of measuring the diameter is shown.

FIG. 12 shows an S-type substrate having a thickness of 100 ° on a Si substrate.
A plurality of i-layers (100) are prepared, and a Ni ₈₁ Fe ₁₉ film having a thickness of 10 °, 20 °, and 30 ° is formed thereon, and a Ni ₈₁ Fe ₁₉ film is not formed. The results obtained by measuring the degree of orientation obtained in each structure in which a Cr ₇₀ Al ₃₀ film having a thickness of 500 ° was further formed thereon and a Cr ₇₀ Al ₃₀ film having a thickness of 50 ° was further formed thereon are shown. In FIG. 12, the C in the thickness of the Ni ₈₁ Fe ₁₉ film serving as the intermediate layer is shown.
It shows a {110} normalized orientation degree normalized by a non-oriented sample of the r ₇₀ Al ₃₀ film. The angle φ handled here is shown in FIG.
As shown in FIG. 3, the normal direction of the laminated film is defined as φ = 0 deg. In addition, (I / I _r ) sin φ on the vertical axis is a quantity obtained by normalizing the average pole density at the angle φ with the pole density of the non-oriented sample given by the following equation (I).

[0028]

(Equation 1)

As a result, as shown in FIGS. 11 and 12, the (110) orientation becomes better as the thickness of the Ni ₈₁ Fe ₁₉ film as the intermediate layer increases. That is, Ni which is an intermediate layer
₈₁ Fe ₁₉ film thickness Cr ₇₀ Al ₃₀ film with increasing {11
It can be seen that the 0 ° orientation becomes better, the crystal grain size becomes larger, and the exchange anisotropic magnetic field tends to become smaller. From the results shown in FIG. 11, it can be seen that the crystal grain size increases as the film thickness of the Ni ₈₁ Fe ₁₉ film increases, so that the crystal orientation is improved and the interface undulations are reduced. Is thought to decrease.

Next, as described above, the interface undulation is generated at the lamination interface.
Contributes to the generation of the exchange anisotropic magnetic field in the presence of
r₇₀Al₃₀Has a ferromagnetic structure in the (200) plane.
Shows an array and shows an antiferromagnetic array in the (110) plane
So Cr₇₀Al₃₀Film and Ni ₈₁Fe₁₉Layered structure with film
At the interface of the structure, antiferromagnetic arrangement is
And the exchange coupling is offset. However, atoms at the interface
If there is unevenness of the size (steps, irregularities, etc.), replace
There is a part where the coupling is not canceled and exchange coupling
Will occur. Therefore, Cr₇₀Al₃₀Underlayer membrane
Atomic size undulations (steps and irregularities only)
It is considered that exchange coupling was obtained due to the above.

From these results, the antiferromagnetic Cr ₇₀ Al
_It has been found that the characteristic of the ₃₀ film is that the critical thickness (300 °) of the antiferromagnetic film thickness at which the exchange anisotropic magnetic field starts to appear is larger than the film thickness of 70 ° of a known material such as Mn—Fe. this is,
This shows that the antiferromagnetic domain wall energy gives the exchange coupling energy. Therefore, the length corresponding to the thickness of the Cr ₇₀ Al ₃₀ film in which the exchange anisotropic magnetic field appears can be considered as the critical length for forming the antiferromagnetic domain wall. Such a concept can be applied not only to the film thickness direction but also to the surface direction. If the crystal grain size is smaller than this critical length, the spin cannot rotate, and the antiferromagnetic domain wall is formed one-dimensionally only in the film thickness direction.

The above description is schematically described as follows.
Assuming a structure in which crystal grains 31 are dispersed inside an AMR ferromagnetic film 30 and an antiferromagnetic film 40 is stacked on the AMR ferromagnetic film 30 as shown in FIG.
When the thickness δ _AF of the ferromagnetic film 30 is smaller than, that is, D> δ
_In the case of the relationship of _AF , it seems that there is a correlation between the exchange anisotropic magnetic field and the crystal grains of the antiferromagnetic film. From the above, the crystal grain size of the Cr ₇₀ Al ₃₀ film is preferably 300 ° or less, but more preferably 140 ° or less so that the exchange anisotropic magnetic field shown in FIG. In the above embodiment, the crystal grain size is controlled by the thickness of the Ni ₈₁ Fe ₁₉ film provided below the Cr ₇₀ Al ₃₀ film. In addition, MgO, AlN, Ta, ZnO, Si, etc. Even when the underlayers are used, it is needless to say that the crystal grain size of the antiferromagnetic film can be controlled by the thickness of the underlayers.

FIG. 15 is an electron micrograph of a cross section of a sample in which a Cr ₇₀ Al ₃₀ film (500 °) and a Ni ₈₁ Fe ₁₉ film (50 °) are laminated on a Si substrate. As it is apparent from this sectional structure, crystal grain size D of Cr ₇₀ Al ₃₀ film, Cr ₇₀
It is apparent that the thickness is smaller than the thickness δ _AF of the Al ₃₀ film.

FIG. 16 shows a base film having a thickness of 100.degree. Si, Ta, AlN, ZnO, MgO on a plurality of Si substrates.
Each layer of O is formed by RF sputtering, and a thickness of 100
The X-ray diffraction patterns of an exchange-coupling film formed by DC sputtering of a Cr ₈₆ Al ₁₄ film of 0 ° and a Ni ₈₁ Fe ₁₉ film of 50 ° thickness, and an exchange-coupling film similar to the above except that no underlayer is used are shown. .

From the results shown in FIG. 16, strong peaks were obtained at (110) and (200) in both the structure with and without the use of various base films.
It was found that the orientation was 0 ° and {100}. FIG.
Is a structure in which the order of lamination of the Cr ₈₆ Al ₁₄ film and the Ni ₈₁ Fel ₁₉ film is reversed in the laminated structure shown in FIG.
X in the case of forming a Cr ₈₆ Al ₁₄ film on an i ₈₁ Fe ₁₉ film)
3 shows a line diffraction pattern. From the results shown in this figure, a strong peak was obtained at (110) in both the structure with and without the use of various underlayers, and the structure with (200)
｛110 盛 り, ｛1
It was found that the orientation was 00 °.

FIG. 18 is a view showing a state in which a 100 ° thick Z
FIG. 19 shows a pole figure of an exchange-coupling film in which an underlayer of nO is formed and a CrAl film and a NiFe film equivalent to the example shown in FIG. 16 are laminated thereon.
A pole figure of an exchange coupling film in which a base film of nO is formed and a CrAl film and a NiFe film equivalent to the example shown in FIG. 11 are stacked thereon is shown. From these figures, when ZnO is the underlying film, the orientation is poor when CrAl is below and NiFe is above,
It can be seen that the orientation is good when CrAl is above and NiFe is below. Incidentally, such a tendency is caused by the underlayer of AlN,
The same was true for the sample using the Ta underlayer.

FIG. 20 shows an M-type substrate having a thickness of 100 ° on a Si substrate.
FIG. 21 shows a pole figure of an exchange coupling film in which a gO underlayer is formed and a CrAl film and a NiFe film equivalent to the example shown in FIG. 10 are laminated thereon, and FIG.
A pole figure of an exchange coupling film in which a gO base film is formed and a CrAl film and a NiFe film equivalent to the example shown in FIG. 11 are stacked thereon is shown. From these figures, when MgO is the underlying film, the orientation is good when CrAl is below and NiFe is above,
It can be seen that the orientation is poor when CrAl is above and NiFe is below. From the results shown in FIGS.
When O, AlN, and Ta are base films, the orientation is better when the formation position of the CrAl film is on the upper side of the NiFe film.
When O is a base film, the formation position of the CrAl film is NiFe
It was found that the orientation was better below the film, and that the orientation was slightly different depending on the vertical relationship between the CrAl film and the NiFe film and the type of the underlying film.

Next, the results of measuring the specific resistance of the CrAl-based sample according to the present invention are shown in Table 1 below. The specific resistance was measured at I = 20 mA by four-terminal measurement.

[0039]

[Table 1]

From the measurement results shown in Table 1, it can be seen that the CrAl-based antiferromagnetic film has a high specific resistance of 12
74 to 1334 μΩcm. Therefore, when the antiferromagnetic film according to the present invention is used for an AMR head or a spin valve head as shown in FIGS. 1, 23, 3, and 4, the current flowing through the antiferromagnetic film can be reduced. It is possible to improve the output of the head and suppress Barkhausen noise. Next, the dependence of the electrical resistivity (ρ) at 400 K (127 ° C.) on the Ga concentration of the CrGa-based sample according to the present invention was examined. The result is shown in FIG. From the results shown in FIG. 22, when Ga is 7 atomic% or more, ρ exceeds 100 μΩcm, and when Ga exceeds 9 atomic%, ρ = 100 μΩcm.
Since it is 200 μΩcm or more and ρ = 310 μΩcm when Ga is 10 atomic%, it is recognized that when the concentration of Ga is increased, the resistance becomes high. Note that, when the temperature is set to around room temperature, ρ further increases. Therefore, it is conceivable that ρ = 100 μΩcm or more even when Ga is 5 atomic%.

[0041]

As described above, according to the present invention, Cr,
An antiferromagnetic film having a body-centered cubic structure composed of at least one element M of Al, Ga, and In;
and a ferromagnetic film containing at least one of the above-described films is laminated so as to be in contact with each other, and magnetic exchange coupling is generated at the interface between the antiferromagnetic film and the ferromagnetic film. It is possible to obtain a configuration that is superior in corrosion resistance and high in specific resistance to FeMn constituting a known antiferromagnetic material film, and provides magnetic exchange coupling. Therefore, the exchange coupling film of the present invention is used as a magnetoresistive element, or
It can be used as an MR head having the same. Further, the exchange coupling film of the present invention includes a longitudinal bias applying structure in an AMR head, a bias structure for pinning a pinning layer in a spin valve head, a bias applying structure of a free ferromagnetic film, and a pinning ferromagnetic film. It can be applied to all of the pinning bias structures. For this reason,
By applying to these, rich in corrosion resistance, high specific resistance,
It is possible to obtain a magnetic head that can exhibit magnetic exchange coupling and has excellent linear response to a change in magnetoresistance.

Next, when an exchange coupling film is formed, any one of MgO, AlN, Ta, and ZnO can be used as a base film, and by using these, an antiferromagnetic film having excellent orientation can be obtained. Alternatively, an exchange coupling film having a ferromagnetic film can be obtained. Further, when the thickness of the antiferromagnetic film is in the range of 300 ° or more, a high value as an excellent exchange anisotropic magnetic field can be obtained, and a film having excellent exchange coupling property can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a structure and a bias magnetic field of an example of an AMR head to which the present invention is applied.

FIG. 2 is an explanatory diagram showing a structure and a bias magnetic field of another example of the AMR head.

FIG. 3 is an explanatory diagram showing a structure of an example of a spin valve head to which the present invention is applied and a bias magnetic field.

FIG. 4 is an explanatory view showing a structure and a bias magnetic field of another example of the spin valve head to which the present invention is applied.

FIG. 5 is a diagram showing an X-ray diffraction pattern of each exchange-coupling film in which a Cr ₈₁ Al ₁₉ film and a Ni ₈₁ Fe ₁₉ film each having a thickness of 100 to 2000 ° are laminated on each Si substrate.

FIG. 6 shows CrA applied to the exchange coupling film according to the present invention.
FIG. 3 is a diagram showing the corrosion potential of 1;

FIG. 7 shows a Si base film and Ni ₈₁ Fe on each Si substrate.
₁₉ film and the variable thickness of the Cr ₈₁ Al ₁₉ film is a diagram showing the film thickness dependency of the exchange anisotropic magnetic field of the exchange coupling films stacked.

FIG. 8: Cr ₈₁ Al ₁₉ of various thickness on each Si substrate
FIG. 4 is a diagram showing the film thickness dependence of the exchange anisotropic magnetic field of each exchange coupling film in which a film and a Ni ₈₁ Fe ₁₉ film are stacked.

FIG. 9 shows the dependence of the exchange anisotropic magnetic field on the CrAl film thickness of an exchange coupling film in which a Cr ₇₀ Al ₃₀ film and a Ni ₈₁ Fe ₁₉ film of various thicknesses are laminated on each Si substrate, and on each Si substrate. FIG. 7 is a diagram showing a comparison of the exchange anisotropy magnetic field dependence of the CrAl film thickness of an exchange coupling film in which an MgO film, a Cr ₇₀ Al ₃₀ film, and a Ni ₈₁ Fe ₁₉ film are stacked.

FIG. 10 shows a Si film and various thicknesses of Cr on each Si substrate.
FIG. 9 is a diagram showing the CrAl film thickness dependence of the exchange anisotropic magnetic field of an exchange coupling film in which a ₇₀ Al ₃₀ film and a Ni ₈₁ Fe ₁₉ film are stacked.

FIG. 11: Cr ₇₀ Al ₃₀ film and Ni ₈₁ Fe on Si substrate
FIG. 4 is a diagram showing the crystal grain size of a CrAl film of an exchange coupling film in which ₁₉ films are stacked, and the dependency of the exchange anisotropic magnetic field on the NiFe film thickness.

FIG. 12 shows a Si layer and various thicknesses of Ni ₈₁ on a Si substrate.
Is a diagram showing Fe ₁₉ film and the Cr ₇₀ Al ₃₀ film and Cr ₇₀ Al ₃₀ film obtained in each structure was formed (110) As a result of measuring the normalized degree of orientation.

13 is a diagram for explaining an angle φ used in the (110) normalized orientation shown in FIG.

FIG. 14 is a diagram schematically illustrating crystal grains, directions of magnetization, and domain wall widths in an antiferromagnetic film in contact with a ferromagnetic film.

FIG. 15 shows a Cr ₇₀ Al ₃₀ film and Ni ₈₁ Fe on a Si substrate.
It is a TEM photograph which shows the cross section of the exchange coupling film which formed ₁₉ films.

FIG. 16 is a view showing an X-ray diffraction pattern of each sample in which various base films are formed on each Si substrate, and a Cr ₈₁ Al ₁₉ film and a Ni ₈₁ Fe ₁₉ film are formed thereon.

FIG. 17 is a view showing an X-ray diffraction pattern of each sample in which various base films are formed on each Si substrate, and a Ni ₈₁ Fe ₁₉ film and a Cr ₈₁ Al ₁₉ film are formed thereon.

FIG. 18 shows a ZnO base film and Cr ₈₁ Al ₁₉ on a Si substrate.
It is a pole figure of a sample to form a film and Ni ₈₁ Fe ₁₉ film.

FIG. 19 shows a ZnO base film and Ni ₈₁ Fe ₁₉ on a Si substrate.
FIG. 4 is a pole figure of a sample on which a film and a Cr ₈₁ Al ₁₉ film are formed.

FIG. 20 shows a MgO base film and Cr ₈₁ Al ₁₉ on a Si substrate.
It is a pole figure of a sample to form a film and Ni ₈₁ Fe ₁₉ film.

FIG. 21 shows a MgO base film and Ni ₈₁ Fe ₁₉ on a Si substrate.
FIG. 4 is a pole figure of a sample on which a film and a Cr ₈₁ Al ₁₉ film are formed.

FIG. 22 is a diagram showing the composition dependence of the electrical resistivity (ρ) of the Cr—Ga-based sample according to the present invention.

FIG. 23 is an explanatory diagram showing a structure and a bias magnetic field of another example of the AMR head to which the present invention is applied.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Soft magnetic material film, 2 ... Electric insulating layer, 3 ... AMR ferromagnetic film, 4 ... Antiferromagnetic film, 7 ... Free ferromagnetic film, 8 ...・ Non-magnetic intermediate layer, 9 ... Pinned ferromagnetic film, 1
0: antiferromagnetic film, 13: antiferromagnetic film, 21: ferromagnetic film, 22: electric insulating layer, 23: AMR ferromagnetic film, 24 ... A longitudinal bias ferromagnetic film, 25 an antiferromagnetic film, 26 a conductive layer;

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kim Masashi, 4-25-19-501, Moiwadai, Taishiro-ku, Sendai, Miyagi Prefecture (72) Inventor Hiroko Uyama 1-7 Yukitani Otsuka-cho, Ota-ku, Tokyo Alps Electric Inside (72) Inventor Akihiro Makino 1-7 Yukitani Otsukacho, Ota-ku, Tokyo Alps Electric Co., Ltd. (72) Inventor Naoya Hasegawa 1-7 Yukitani-Otsukacho, Ota-ku, Tokyo Alps Electric Co., Ltd. Inside

Claims (16)

[Claims] 1. Cr and Al, G of the Group 3b element of the periodic table
an antiferromagnetic film mainly composed of a crystal phase having a body-centered cubic structure composed of at least one element M of a and In;
e, a ferromagnetic film containing at least one of Ni and Co is laminated so as to be in contact with each other, and magnetic exchange coupling is generated at an interface between the antiferromagnetic film and the ferromagnetic film. An exchange-coupling membrane characterized in that: 2. The method according to claim 1, wherein the antiferromagnetic film is {100}, {11}
The exchange-coupling film according to claim 1, wherein the exchange-coupling film is preferentially oriented to any one of 0 °. 3. The exchange-coupling film according to claim 1, wherein a crystal grain size D of the antiferromagnetic film is smaller than a domain wall width δ _AF of the antiferromagnetic film. . 4. The antiferromagnetic material film has a crystal grain size D ≦ 3.
The exchange coupling membrane according to claim 3, wherein the exchange coupling membrane has a relationship of 00 °. 5. The antiferromagnetic film and the ferromagnetic film are formed on a base material via a base film, and the base film is made of MgO, A
1 of IN, Ta, ZnO, Si, and Fe-Ni alloy
The exchange-coupling membrane according to any one of claims 1 to 4, comprising at least one species. 6. The exchange-coupling film according to claim 1, wherein the spontaneous corrosion potential of the antiferromagnetic film shows a positive value with respect to the saturated calomel electrode. 7. The exchange coupling film according to claim 1, wherein the thickness of the antiferromagnetic film is 300 ° or more. 8. The antiferromagnetic film has a specific resistance of 200 μΩcm.
The exchange coupling membrane according to any one of claims 1 to 7, wherein the exchange coupling membrane is configured as described above. 9. The exchange coupling film according to claim 1, wherein said antiferromagnetic film is represented by the following composition formula. Cr _x Al _y, where x and y indicating the composition ratio are atomic%, and 60 ≦ x ≦ 9.
0, 10 ≦ y ≦ 40. 10. The x is 65 ≦ x ≦ 80, and y is 20 ≦ y ≦
The exchange coupling membrane according to claim 9, wherein the exchange coupling membrane has a range of 35. 11. The exchange coupling film according to claim 1, wherein said antiferromagnetic film is represented by the following composition formula. Cr _x Ga _z here, x indicating the composition ratio, z is in atomic%, 85 ≦ x ≦ 9
5, 5 ≦ z ≦ 15. 12. The exchange coupling film according to claim 1, wherein said antiferromagnetic film is represented by the following composition formula. Cr _x an In _w here, x indicating the composition ratio, w is, in atomic%, 85 ≦ x ≦ 9
5, 5 ≦ w ≦ 15. 13. Cr and Al, G of Group 3b elements of the periodic table
a body-centered cubic antiferromagnetic film composed of at least one element M of a and In and a ferromagnetic film containing at least one of Fe, Ni, and Co so as to be in contact with each other An exchange coupling film that causes a magnetic exchange coupling at an interface between the antiferromagnetic film and the ferromagnetic film to apply a longitudinal bias to the ferromagnetic film; And a soft magnetic material film for applying a lateral bias to the ferromagnetic film. 14. Cr and Al, G of Group 3b elements of the periodic table
an antiferromagnetic film mainly composed of a crystal phase having a body-centered cubic structure composed of at least one element M of a and In;
e, a ferromagnetic film containing at least one of Ni and Co is laminated so as to be in contact with each other, and magnetic exchange coupling is generated at an interface between the antiferromagnetic film and the ferromagnetic film to form the magnetic film. A magnetoresistive effect element comprising: an exchange coupling film having a ferromagnetic film as a pinned magnetic film; and a ferromagnetic film having a single magnetic domain with at least a nonmagnetic film interposed therebetween. 15. Cr and Al, G of Group 3b elements of the periodic table
an antiferromagnetic film mainly composed of a crystal phase having a body-centered cubic structure composed of at least one element M of a and In;
e, a ferromagnetic film containing at least one of Ni and Co is laminated so as to be in contact with each other, and magnetic exchange coupling is generated at an interface between the antiferromagnetic film and the ferromagnetic film to form the magnetic film. An exchange coupling film for applying a longitudinal bias to the ferromagnetic film, and a soft magnetic material film for applying a lateral bias to the ferromagnetic film laminated at least with a non-magnetic film interposed therebetween; A magnetoresistive element for reading the recorded magnetic recording, and an inductive head for writing magnetic recording on a magnetic recording medium, comprising at least a magnetic core made of a soft magnetic material forming a magnetic circuit, a magnetic gap and a coil. A magnetic head comprising: 16. Cr and Al, G of Group 3b elements of the periodic table
an antiferromagnetic film mainly composed of a crystal phase having a body-centered cubic structure composed of at least one element M of a and In;
e, a ferromagnetic film containing at least one of Ni and Co is laminated so as to be in contact with each other, and magnetic exchange coupling is generated at an interface between the antiferromagnetic film and the ferromagnetic film to form the magnetic film. A magnetoresistive element in which an exchange-coupling film having a ferromagnetic film as a pinned magnetic film and a ferromagnetic film in which a single magnetic domain is formed via at least a nonmagnetic film are laminated; and at least a magnetic circuit is formed. A magnetic head comprising: a magnetic core made of a soft magnetic material, a magnetic gap, and a coil; and an inductive head for writing magnetic recording on a magnetic recording medium.