JPH09270545A - Multilayer magnetoresistance effect film, magnetoresistance effect element and magnetoresistance effect type magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a product revealing a good macro-magnetoresistance effect with an antiferromagnetic coupling hard to break against a sense current by providing an anisotropy for the magnetoresistance effect. SOLUTION: A multilayer manetoresistance effect film has a multilayer film composed of laminated magnetic and nonmagnetic layers and is made to reveal an abrupt magnetoresistance change with the magnetic field change in a direction x even if the magnetic field is low but a gentle magnetoresistance change with the field change in a direction y perpendicular to x, when the field is low. When the direction x is parallel to the sense current flowing direction and a field H is applied in the direction x, magnetoresistance effect curves is sharp. When the direction y is perpendicular to the sense current flowing direction and the field H is applied in the direction y, it is made to reveal a gentle magnetoresistance effect curve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layered magnetoresistive film having a multi-layered film in which a magnetic layer and a non-magnetic layer are laminated and showing a giant magnetoresistive effect. The present invention also relates to a magnetoresistive effect element and a magnetoresistive effect type magnetic head using such a multilayer magnetoresistive effect film.

[0002]

2. Description of the Related Art A magnetoresistive effect element is an element for detecting a magnetic field, and usually has a magnetoresistive effect film formed in a strip shape,
And a pair of electrodes attached to both ends of the magnetoresistive film. Here, the magnetoresistive film is a thin film whose resistance value changes according to the magnitude of the external magnetic field. When detecting an external magnetic field using the magnetoresistive element, normally, a fixed sense current is supplied to the magnetoresistive film via a pair of electrodes, and a voltage change of the sense current is detected.
That is, in the magnetoresistive element, the resistance of the magnetoresistive film changes due to a change in the external magnetic field, and this resistance change is detected as a voltage change of the sense current.

[0003] Such a magnetoresistive element is
For example, it is used for a reproducing magnetic head. here,
A reproducing magnetic head using a magnetoresistive element is called a magnetoresistive head, and detects a signal magnetic field from a recording medium as a change in resistance of the magnetoresistive element.

Heretofore, as such a magnetoresistive element, a magnetoresistive element using a Ni—Fe alloy film (so-called permalloy film) exhibiting an anisotropic magnetoresistive effect as the magnetoresistive effect film has been widely used. Have been. However, a magnetoresistance effect element using a permalloy film has a small magnetoresistance change rate, and a magnetoresistance effect element exhibiting a larger magnetoresistance change rate is desired.

[0005] In particular, the magnetoresistance change rate of a magnetoresistive element using a permalloy film is as small as about 2% or less under conditions used for a magnetic head or the like. Therefore, with the increase in the density of magnetic recording, there is a strong demand for a magnetoresistive element having a greater magnetoresistance effect to be used in a magnetoresistive magnetic head.

On the other hand, in recent years, an extremely large magnetoresistance effect (so-called giant magnetoresistance effect) has been obtained in a multilayer film having an artificial lattice film structure in which different kinds of metals and the like are alternately stacked by several atomic layers. It has been reported. In particular,
For example, MNBaibich et al., “Phys. Rev. Lett. 61, p.
2472 (1988) ", it has been reported that a multilayer film having an artificial lattice film structure in which a magnetic layer made of Fe and a nonmagnetic conductor layer made of Cr are stacked exhibits a giant magnetoresistance effect. SSPParkin et al., “Phys. Rev. Lett.
66, p2152 (1991) ", wherein a magnetic layer made of Co;
It has been reported that a multilayer film having an artificial lattice film structure in which a nonmagnetic conductor layer made of Cu is laminated exhibits a giant magnetoresistance effect.

The giant magnetoresistance effect is obtained in the multilayer film having such an artificial lattice film structure because the RKKY (Ruderman-Kittel-Kasuya-Yoshida) mutual between the magnetic layers via conduction electrons in the non-magnetic conductor layer. It is considered that the anti-ferromagnetic coupling between the opposing magnetic layers causes an antiparallel spin state to occur, and as a result, spin-dependent scattering occurs.

A magnetoresistive film composed of a multilayer film having such an artificial lattice film structure (hereinafter, referred to as a multilayer magnetoresistive film) is much larger than a magnetoresistive effect obtained by a conventional permalloy film. In order to exhibit the magnetoresistance effect, application to a magnetoresistance effect element and application to devices such as a magnetoresistance effect type magnetic head are expected.

[0009] However, the multilayer magnetoresistive film has a problem that although the amount of change in the resistance value is large, the amount of change in the magnetic field required for the resistance change is large. That is, the sensitivity of the multilayer magnetoresistive film is insufficient for use in a device that needs to detect a weak magnetic field, such as a magnetic head. Therefore, in order to apply a multilayer magnetoresistive film to a device that needs to detect a weak magnetic field, such as a magnetic head, it is necessary to obtain a large resistance change even with a small magnetic field change. I have.

Therefore, as a multilayer magnetoresistive film capable of obtaining a large resistance change even with a smaller magnetic field change, for example,
It has been proposed to use a soft magnetic material such as NiFe or NiFeCo for the magnetic layer forming the multilayer magnetoresistive effect film.

[0011]

However, the magnetoresistive effect element using the multilayer magnetoresistive effect film as described above is not affected by the magnetic field generated by the sense current when the sense current is passed to detect the external magnetic field. However, there is a problem that the antiferromagnetic coupling in the multilayer magnetoresistive effect film is broken and the magnetoresistive effect is lowered.

In particular, in a multilayer magnetoresistive effect film using a soft magnetic material such as NiFe or NiFeCo for the magnetic layer, the antiferromagnetic coupling in the multilayer magnetoresistive effect film is easily broken by the magnetic field generated by the sense current. Therefore, in order to obtain a large resistance change with a smaller magnetic field change,
In a multilayer magnetoresistive effect film using a soft magnetic material such as NiFe or NiFeCo for a magnetic layer, breaking of antiferromagnetic coupling due to a magnetic field generated by a sense current is a serious problem.

As described above, in the magnetoresistive effect element in which the antiferromagnetic coupling is destroyed when the sense current is supplied, the magnetoresistive effect is lowered when the sense current is supplied, so that a large magnetoresistive effect is obtained. Is not obtained and is not suitable as an element for magnetic field detection. As a matter of course, even if such a magnetoresistive effect element is used in a device such as a magnetic head, a large magnetoresistive effect cannot be obtained, so that the reproduction output cannot be increased.

The present invention has been proposed in view of such a conventional situation, and even if a sense current is supplied, the antiferromagnetic coupling is not easily broken, and a good giant magnetoresistive effect is exhibited. It is intended to provide a multilayer magnetoresistive effect film. Another object of the present invention is to provide a magnetoresistive effect element capable of detecting a weak magnetic field or a minute magnetic field change with high sensitivity by using such a multilayer magnetoresistive effect film. . Another object of the present invention is to provide a magnetoresistive effect type magnetic head capable of obtaining a high reproduction output by using such a multilayer magnetoresistive effect film.

[0015]

The present inventor has conducted studies on multilayer magnetoresistive films having various characteristics in order to achieve the above-mentioned object, and as a result, has anisotropy in the magnetoresistive effect of the multilayer magnetoresistive films. It was found that a multi-layered magnetoresistive effect film that is not easily affected by the magnetic field generated by the sense current can be obtained by imparting the property, and thus the present invention has been accomplished.

That is, the multi-layered magnetoresistive effect film according to the present invention is a multi-layered magnetoresistive effect film having a multi-layered film in which a magnetic layer and a non-magnetic conductor layer are laminated, and the magnetic field in the x direction and y which are orthogonal to each other Regarding the magnetic field in the direction, a steep reluctance change is shown with respect to the change of the magnetic field in the x direction even if the magnitude of the magnetic field is small, and is gentle with respect to the change of the magnetic field in the y direction while the magnitude of the magnetic field is small. It is characterized by exhibiting a large change in magnetic resistance.

Since the magnetoresistive effect of the multilayer magnetoresistive film has anisotropy, the effect of the magnetic field generated by the sense current is reduced while maintaining the high magnetoresistive effect, and the antiferromagnetic coupling is destroyed. Can be prevented.

That is, the external magnetic field to be detected is applied in a direction showing a steep magnetoresistance change even when the magnitude of the magnetic field is small, and the magnetic field generated by the sense current is small while the magnitude of the magnetic field is small. Is applied in the direction showing a gradual change in magnetoresistance, this multilayer magnetoresistance effect film is sensitive to an external magnetic field and exhibits a good magnetoresistance effect. On the other hand, they are less sensitive and less affected. At this time, since the multilayer magnetoresistive effect film is sensitive to an external magnetic field and exhibits a favorable magnetoresistive effect, the external magnetic field can be detected with high sensitivity. Moreover, since the multilayer magnetoresistive effect film is not much affected by the magnetic field generated by the sense current, the antiferromagnetic coupling is less likely to be broken by the magnetic field generated by the sense current.

The magnetoresistive effect element according to the present invention is characterized in that the above-mentioned multilayer magnetoresistive effect film according to the present invention is used at least in part. This magnetoresistive element uses a multi-layered magnetoresistive effect film that has a good anti-ferromagnetic coupling and is capable of exhibiting excellent giant magnetoresistive effect. Therefore, it can detect weak magnetic fields and minute magnetic field changes with high sensitivity. It is possible to

The magnetoresistive effect magnetic head according to the present invention is characterized in that the above-described multilayer magnetoresistive effect film according to the present invention is used at least in part. This magnetoresistive effect magnetic head uses a multi-layered magnetoresistive effect film in which the antiferromagnetic coupling is hard to be destroyed and which exhibits a good giant magnetoresistive effect, and thus is sensitive to a weak magnetic field and a minute magnetic field change. It is possible to detect
Therefore, a large reproduction output can be obtained.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the following examples, and it goes without saying that the shape, material, and the like can be arbitrarily changed without departing from the gist of the present invention.

First, an example of an embodiment of a multilayer magnetoresistive film to which the present invention is applied will be described.

The multilayer magnetoresistive effect film according to the present embodiment is a magnetoresistive effect film exhibiting a giant magnetoresistive effect and is formed by a sputtering method. When performing sputtering, the ultimate vacuum degree is set to 1 × 10 ⁻⁴ Pa or less,
Ar gas pressure was 0.1-0.5 Pa.

As shown in FIG. 1, the multilayer magnetoresistive effect film 1 includes a lower magnetic layer 3 formed on a substrate 2, a multilayer film 4 laminated on the lower magnetic layer 3, and a multilayer film 4. And the upper magnetic layer 5 laminated on the.

Here, the lower magnetic layer 3 and the upper magnetic layer 5
Is a magnetic thin film made of a ferromagnetic material, and is a lower magnetic layer 3
Is a Ni—Fe thin film having a thickness of about 7 nm, and the upper magnetic layer 5 is a Ni—Fe thin film having a thickness of about 5 nm.
The multilayer film 4 is formed by repeatedly stacking the nonmagnetic conductor layer 10 and the magnetic layer 11 for eight cycles. Here, the non-magnetic layer 10 is made of a Cu thin film having a thickness of about 2.1 nm, and the magnetic layer 11 is made of an Fe thin film having a thickness of about 0.42 nm and the first magnetic layer 11a. A second magnetic layer 11b made of a Ni thin film having a thickness of about 1.58 nm is laminated. The magnetic layers 11 constituting the multilayer film 4 are antiferromagnetically coupled, and their magnetization directions are alternately reversed in the absence of an external magnetic field.

The layers constituting the multilayer magnetoresistive effect film are not limited to the above-mentioned examples, and it is sufficient that the multilayer magnetoresistive effect film as a whole exhibits a giant magnetoresistive effect. .

As described above, the multilayer magnetoresistive effect film 1 according to this embodiment has the Ni / Fe / on the lower magnetic layer 3.
A multilayer film 4 formed by repeatedly stacking stacked films made of Cu for 8 cycles is stacked, and the upper magnetic layer 5 is formed on the second magnetic layer 11b formed on the uppermost layer of the multilayer film 4. . Here, the film thickness of the magnetic layer 11 forming the multilayer film 4,
That is, the film thickness of the first magnetic layer 11a and the second magnetic layer 11
The total film thickness of b is about 2.0 nm. That is, in the multilayer magnetoresistive effect film 1, the lower magnetic layer 3 thicker than the magnetic layer 11 forming the multilayer film 4 is arranged below the multilayer film 4 and the magnetic layer 11 forming the multilayer film 4 is formed. A thick upper magnetic layer 5 is arranged on the multilayer film 4 and is configured.

The magnetic layer 11 forming the multilayer film 4 is described.
Is not limited to the laminated film of the Ni thin film and the Fe thin film as described above. For example, a laminated film of the Ni alloy thin film and the Fe alloy thin film or a Ni—Fe alloy thin film and the Ni—Fe thin film.
A laminated film with a system alloy thin film, a laminated film with a Ni—Fe system alloy thin film and a Ni—Fe system alloy thin film having a composition different from that of the Ni—Fe system alloy thin film are also suitable. In addition, the multilayer film 4
The material of the non-magnetic conductor layer 10 constituting the is not limited to Cu. For example, a material containing at least one selected from Cu, Ag, Au, Cu alloy, Ag alloy or Au alloy is widely used. It is possible.

FIG. 2 shows the results of measuring the magnetoresistive effect by supplying the sense current Is to the multilayer magnetoresistive effect film 1 as described above. Here, in FIG. 2A, when the direction parallel to the main surface of the multilayer magnetoresistive effect film 1 and parallel to the direction in which the sense current Is flows is the x direction, the magnetic field H is applied in the x direction. The magnetic resistance effect curve at this time is shown. Also,
FIG. 2B is parallel to the main surface of the multilayer magnetoresistive effect film 1,
When the direction perpendicular to the direction in which the sense current Is flows is the y direction, the magnetoresistive effect curve when the magnetic field H is applied in the y direction is shown. That is, FIG. 2A shows a magnetoresistive effect curve measured by applying a magnetic field H parallel to the sense current Is, and FIG. 2B shows a magnetic field perpendicular to the sense current Is. The magnetoresistive effect curve measured by applying H is shown.

As is apparent from FIGS. 2A and 2B, the magnetoresistive effect of this multilayer magnetoresistive effect film 1 has anisotropy, and it is Even if the magnitude of the magnetic field is small, the magnetic resistance changes abruptly, and with respect to the change in the magnetic field in the y direction, the magnetic resistance changes gradually while the magnitude of the magnetic field is small.

That is, the multilayer magnetoresistive effect film 1 is
It shows a characteristic that the resistance value immediately and monotonously decreases as the magnetic field increases in response to a change in the magnetic field in the x direction, but maintains a high resistance value up to a certain magnetic field in response to a change in the magnetic field in the y direction. Shows the characteristics that

As described above, the multilayer magnetoresistive effect film 1 according to the present embodiment is sensitive to a magnetic field change in the x direction and insensitive to a magnetic field change in the y direction. Therefore, by applying the external magnetic field to be detected in the x direction and applying the magnetic field generated by the sense current Is in the y direction, the magnetic field generated by the sense current Is is maintained while maintaining a high magnetoresistive effect. The influence of the magnetic field can be reduced to prevent breakage of the antiferromagnetic coupling.

That is, the multilayer magnetoresistive effect film 1 is
Since it is sensitive to magnetic field changes in the x-direction, by applying an external magnetic field to be detected in the x-direction,
The external magnetic field can be detected with high sensitivity. Moreover,
Since the multilayer magnetoresistive effect film 1 is insensitive to the change in the magnetic field in the y direction, by applying the magnetic field generated by the sense current Is in the y direction, anti-strength due to the magnetic field generated by the sense current Is is exerted. It is possible to prevent breakage of magnetic coupling.

Incidentally, such anisotropy of the magnetoresistive effect can be realized by controlling the conditions when forming each layer constituting the multilayer magnetoresistive effect film 1, for example. Specifically, for example, the multilayer magnetoresistive effect film 1
When the respective layers constituting the above are formed, the anisotropy of the magnetoresistive effect as described above can be realized by controlling the incident angle of the sputtered particles or applying a magnetic field from the outside.

Here, as a comparative example, a magnetoresistive effect curve of a conventional multilayer magnetoresistive effect film is shown in FIG. Here, FIG. 3A shows a magnetoresistive effect curve when the magnetic field H is applied in the x direction, that is, a magnetoresistive effect curve measured by applying the magnetic field H parallel to the sense current Is. There is. Further, FIG. 3B shows a magnetoresistive effect curve when the magnetic field H is applied in the y direction, that is, a magnetoresistive effect curve measured by applying the magnetic field H perpendicular to the sense current Is. . As described above, the magnetoresistive effect of the conventional multi-layered magnetoresistive film is isotropic, and the same magnetoresistive effect occurs when a magnetic field is applied in the x direction and when a magnetic field is applied in the y direction.

As is clear from FIG. 3, such a multilayer magnetoresistive film sensitively reacts to changes in the magnetic field in either the x direction or the y direction. Therefore, whether the magnetic field generated by the sense current Is is applied in the y direction or the x direction, the multilayer magnetoresistive effect film is easily affected by the magnetic field generated by the sense current Is. Therefore, in the conventional multilayer magnetoresistive film exhibiting an isotropic magnetoresistive effect, the antiferromagnetic coupling is easily broken by the magnetic field generated by the sense current Is,
It was not suitable for applications such as supplying a sense current Is to detect an external magnetic field.

On the other hand, in the multilayer magnetoresistive effect film 1 according to the present embodiment, as described above, even if the sense current Is is supplied, the antiferromagnetic coupling is hard to be broken, so that the sense current Is is reduced. It is very suitable for applications such as supplying and detecting external magnetic fields.

Incidentally, "Journal of Applied Magnetics of Japan" Vol. 1
7, No. The existence of anisotropy in the magnetoresistive effect is also pointed out in the multilayer magnetoresistive effect film using the NiFeCo film, which is described on page 2, 395 (1993).

However, in such a conventionally known multilayer magnetoresistive effect film, even if anisotropy is observed in the magnetoresistive effect, they have resistance values with respect to magnetic fields from all directions as the magnetic field increases. Shows a tendency to decrease monotonically.

That is, in the conventionally known multilayer magnetoresistive effect film, the magnetoresistive effect characteristic with respect to the change in the magnetic field in the x direction,
Even if there is a slight difference in the magnetoresistive effect characteristics with respect to the change in the magnetic field in the y direction, all of them have such characteristics that the resistance value immediately and monotonously decreases as the external magnetic field increases. Like the multilayer magnetoresistive film according to
With respect to the change in the magnetic field in the y direction, there is no characteristic that maintains a high resistance up to a certain magnetic field.

Therefore, in the conventionally known multilayer magnetoresistive effect film, even if anisotropy is observed in the magnetoresistive effect, as in the above-mentioned comparative example, it is easily affected by the magnetic field generated by the sense current Is, and the anti-reflective effect is reversed. It is still the case that ferromagnetic coupling is easily broken.

Next, an example of an embodiment of a magnetoresistive effect element to which the present invention is applied will be described.

As shown in FIG. 4, the magnetoresistive effect element 20 according to the present embodiment has a strip-shaped multi-layered magnetoresistive effect film 2.
1 and a pair of electrodes 22 and 23 attached to both ends of the multilayer magnetoresistive effect film 21.

The multilayer magnetoresistive effect film 21 is a multilayer film exhibiting a giant magnetoresistive effect in which the resistance value greatly changes depending on the magnitude of the external magnetic field. It is processed into a strip shape so that the axial direction is sensitive to the magnetic field change and the single axis direction is insensitive to the magnetic field change. In this embodiment, the width W of the multilayer magnetoresistive effect film 21 is about 2 μm.
m, and the length L was about 10 μm.

The pair of electrodes 22 and 23 attached to both ends of the multilayer magnetoresistive effect film 21 are for supplying a sense current Is to the multilayer magnetoresistive effect film 21 when detecting an external magnetic field. is there. In the present embodiment,
The distance D between the electrode 22 and the electrode 23, that is, the length of the magnetic sensitive portion of the magnetoresistive effect element 20 was set to about 8 μm.

When the external magnetic field is detected by the magnetoresistive effect element 20 as described above, the multilayer magnetoresistive film is parallel to the long axis direction of the multilayer magnetoresistive effect film 21 through the pair of electrodes 22 and 23. A sense current Is is supplied to the effect film 21.

At this time, the magnetic field generated by the sense current Is is generated substantially parallel to the minor axis direction of the multilayer magnetoresistive effect film 21. Then, in the magnetoresistive effect element 20 according to the present embodiment, as described above, the minor axis direction of the multilayer magnetoresistive effect film 21 is made insensitive to the magnetic field change. Therefore, the multilayer magnetoresistive effect film 21 of the magnetoresistive effect element 20 is hardly affected by the magnetic field generated by the sense current Is, and the antiferromagnetic coupling is hard to be broken. Therefore, the magnetoresistive effect element 20 exhibits a stable magnetoresistive effect even when the sense current Is is supplied.

Further, when the external magnetic field is detected by the magnetoresistive effect element 20, the external magnetic field to be detected is parallel to the direction in which the sense current Is flows, that is, the multilayer structure, as shown by an arrow H in FIG. It is applied in the major axis direction of the magnetoresistive film 21. As described above, in the magnetoresistive effect element 20 according to the present embodiment, the major axis direction of the multilayer magnetoresistive effect film 21 is made sensitive to the magnetic field change. Therefore, the external magnetic field causes the multilayer magnetoresistive film 2
The external magnetic field can be detected with high sensitivity by applying the magnetic field in the long axis direction of 1.

Table 1 shows the results of measuring the output when the external magnetic field is detected by the magnetoresistive effect element 20 as described above.
Shown in Here, the output is obtained as a voltage change of the sense current Is. In Table 1, as a comparative example, measurement results of a magnetoresistive effect element formed in the same manner as the magnetoresistive effect element 20 using a conventional multilayer magnetoresistive effect film exhibiting an isotropic magnetoresistive effect are shown. Is also shown. That is, in Table 1, the example shows the magnetoresistive element 20 according to the present embodiment, and the comparative example shows
The conventional magnetoresistive effect element using the multilayer magnetoresistive effect film which shows an isotropic magnetoresistive effect is shown.

[0050]

[Table 1]

As shown in Table 1, the magnetoresistive effect element 20 according to the present embodiment has a sensitivity about 1.8 times higher than that of the conventional magnetoresistive effect element. That is, the magnetoresistive effect element 20 according to the present embodiment can detect a weak magnetic field or a minute magnetic field change with extremely high sensitivity.

Next, an example of an embodiment of a magnetoresistive effect type magnetic head to which the present invention is applied will be described.

The magnetoresistive effect magnetic head according to the present embodiment is a so-called vertical type in which the magnetoresistive effect film is arranged so that the major axis direction of the magnetoresistive effect film is perpendicular to the sliding direction of the recording medium. Is a magnetoresistive effect type magnetic head. Regarding the vertical type magnetoresistive effect magnetic head, for example, "
H.Suyama et al. IEEE (Institute of Telecommunications) Transa
ction on Magnetics, MAG-24, p2612 (1988) ”.

As shown in FIG. 5, the magnetoresistive effect magnetic head 30 according to the present embodiment is formed on a substrate 31 made of a nonmagnetic material with a nonmagnetic layer 32 interposed therebetween. On the lower shield core 33 formed on the lower shield core 33, the non-magnetic layer 34 formed on the lower shield core 33, the magnetoresistive effect element 35 formed on the non-magnetic layer 34, and the magnetoresistive effect element 35. The formed nonmagnetic layer 36 and the nonmagnetic layer 3 so as to pass over the magnetoresistive effect element 35.
6, a bias conductor 37 arranged in the inner part 6 and an upper shield core 38 formed on the non-magnetic layer 36. Although not shown, a protective layer for protecting the magnetoresistive head 30 is formed on the magnetoresistive head 30.

In the magnetoresistive effect magnetic head 30, the lower shield core 33 serves to magnetically shield the lower part of the magnetoresistive effect element 35 and is made of a magnetic material. Similarly, the upper shield core 38 is for magnetically shielding the upper portion of the magnetoresistive effect element 35, and is made of a magnetic material. The non-magnetic layer 34 disposed between the lower shield core 33 and the magneto-resistance effect element 35
To form a magnetic gap between them, and is made of a non-magnetic insulating material. Similarly, the magnetoresistive element 3
5 and the upper magnetic shield 38 and the non-magnetic layer 3 disposed between
6 is for forming a magnetic gap between the magnetoresistive effect element 35 and the upper shield core 38, and is made of a non-magnetic insulating material.

The magnetoresistive effect element 35 arranged between the nonmagnetic layer 34 and the nonmagnetic layer 36 has the same structure as the magnetoresistive effect element 20 according to the above-mentioned embodiment, and The multilayer magnetoresistive effect film 35a to which the invention is applied, and the electrode 3 derived from the front end portion of the multilayer magnetoresistive effect film 35a.
5b and an electrode 35c led out from the rear end of the multilayer magnetoresistive effect film 35a.

Here, the multilayer magnetoresistive effect film 35a is formed in a strip shape like the multilayer magnetoresistive effect film 21 of the magnetoresistive effect element 20 according to the above-mentioned embodiment, and the front end portion thereof is a recording medium. It is exposed on the facing surface A.

When the multilayer magnetoresistive effect film 35a is formed, for example, the multilayer magnetoresistive effect film 35a is deposited on the nonmagnetic layer 34 so as to face the recording medium facing surface A,
Thereafter, the multilayer magnetoresistive film 35a is patterned into a predetermined strip pattern by using a known photolithography technique. Here, the patterning is, for example,
This is performed by applying processes such as application of a photoresist, pattern exposure, development, and ion beam etching using the photoresist as a mask.

The electrode 35b led out from the front end portion and the electrode 35c led out from the rear end portion of the multilayer magnetoresistive effect film 35a have a sense current I applied to the multilayer magnetoresistive effect film 35a.
s, and is made of a good conductor material.
These electrodes 35b and 35c are also formed by patterning into a predetermined pattern by a photolithography technique, similarly to the multilayer magnetoresistive film 35a.

The bias conductor 37 formed so as to pass above the magnetoresistive effect element 35 applies a bias magnetic field to the magnetoresistive effect element 35 in order to improve the sensitivity of the magnetoresistive effect element 35. Is for
The magnetoresistive effect element 35 is patterned so as to pass through the magnetic sensitive portion, that is, the upper portion of the multilayer magnetoresistive effect film 35a.

The magnetoresistive effect type magnetic head 3 as described above.
FIG. 6 shows how an information signal is reproduced from a recording medium by 0.
Shown in Here, FIG. 6 is a diagram schematically showing how the magnetoresistive effect magnetic head 30 reproduces an information signal, and illustrates the essential part of the magnetoresistive effect magnetic head 30 and the recording medium 40. ing.

As shown in FIG. 6, when reproducing an information signal from the recording medium 40, the magnetoresistive head 3 is used.
The recording medium facing surface A of the recording medium 40 is opposed to the recording track of the recording medium 40, and a constant sense current Is is supplied from the electrodes 35b and 35c to the multilayer magnetoresistive film 35a. Detects a voltage change between them.

That is, in the magnetoresistive effect magnetic head 30, the resistance of the multilayer magnetoresistive effect film 35a changes according to the change in the direction of the magnetic field recorded on the recording track of the recording medium 40. Therefore, the multilayer magnetoresistive film 35
The information signal from the recording medium 40 is reproduced by detecting the resistance change of a as a voltage change between the electrode 35b and the electrode 35c.

The magnetoresistive effect type magnetic head 3 as described above.
At 0, the magnetic field generated by the sense current Is is generated substantially parallel to the minor axis direction of the multilayer magnetoresistive effect film 35a. In the magnetoresistive effect magnetic head 30 according to the present embodiment, the minor axis direction of the multilayer magnetoresistive effect film 35a is insensitive to the magnetic field change. Therefore, the multi-layer magnetoresistive effect film 35a has a sense current I
It is hard to be affected by the magnetic field generated by s, and the antiferromagnetic coupling is not easily broken. Therefore, the magnetoresistive effect magnetic head 30 can obtain a stable and large output.

In the magnetoresistive effect type magnetic head 30 as described above, the multilayer magnetoresistive effect film is arranged so that the major axis direction of the multilayer magnetoresistive effect film 35a is perpendicular to the sliding direction of the recording medium 40. 35a is arranged. Therefore,
The signal magnetic field from the recording medium 40 is parallel to the direction in which the sense current Is flows, that is, the multilayer magnetoresistive effect film 3
It will be applied in the major axis direction of 5a. In the magnetoresistive effect magnetic head 30 according to the present embodiment, the major axis direction of the multilayer magnetoresistive effect film 35a is made sensitive to the magnetic field change. Therefore, the magnetoresistive effect magnetic head 30 can detect the signal magnetic field from the recording medium 40 with high sensitivity.

In the present embodiment, the magnetoresistive effect type magnetic head is mentioned as the device utilizing the magnetoresistive effect. However, the multilayer magnetoresistive effect film and the magnetoresistive effect element according to the present invention have the magnetoresistive effect. It is also applicable to devices other than the magnetic head. Specifically, the multilayered magneto-resistance effect film and the magneto-resistance effect element according to the present invention can be applied to, for example, a magnetic sensor such as a geomagnetic direction sensor.

[0067]

As is apparent from the above description, the multilayer magnetoresistive effect film according to the present invention reduces the influence of the magnetic field generated by the sense current Is while maintaining a high magnetoresistive effect against the external magnetic field. It is possible to prevent breakage of the antiferromagnetic coupling. That is, according to the present invention, it is possible to provide a multilayer magnetoresistive effect film in which the antiferromagnetic coupling is not easily broken even when a sense current is supplied, and which exhibits a good giant magnetoresistive effect.

Since the magnetoresistive effect element according to the present invention uses the multi-layered magnetoresistive effect film exhibiting a good giant magnetoresistive effect as described above, it is highly sensitive to a weak magnetic field and a minute magnetic field change. It is possible to detect. That is, according to the present invention, it is possible to provide a magnetoresistive effect element suitable for a device that needs to detect a weak magnetic field, such as a magnetic head.

Further, since the magnetoresistive effect magnetic head according to the present invention uses the multi-layered magnetoresistive effect film exhibiting a good giant magnetoresistive effect as described above, a large reproduction is achieved even with a weak signal magnetic field. It is possible to get the output. That is, according to the present invention, the reproduction characteristics are very excellent,
A magnetic resistance effect type magnetic head suitable for high density recording can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a structural example of a multilayer magnetoresistive effect film to which the present invention is applied.

FIG. 2 is a diagram showing an example of a magnetoresistive effect curve of a multilayer magnetoresistive effect film to which the present invention is applied.

FIG. 3 is a diagram showing an example of a magnetoresistive effect curve of a conventional multilayer magnetoresistive effect film.

FIG. 4 is a plan view showing an outline of a configuration example of a magnetoresistive effect element to which the present invention is applied.

FIG. 5 is a cross-sectional view showing a configuration example of a magnetoresistive effect magnetic head to which the present invention is applied.

6 is a main-part perspective view schematically showing how an information signal is reproduced by the magnetoresistive effect magnetic head shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 multi-layer magnetoresistive film, 2 substrate, 3 lower magnetic layer, 4 multi-layer film, 5 upper magnetic layer, 10 non-magnetic conductor layer, 11 magnetic layer, 11a first magnetic layer, 11b second magnetic layer, 20 magnetic Resistance effect element, 21 Multi-layered magneto-resistance effect film, 22, 23 Electrodes, 30 Magneto-resistance effect type magnetic head, 31 Base body, 32 Non-magnetic layer, 33 Lower shield core, 34 Non-magnetic layer, 35 Magneto-resistance effect element, 35a Multi-layer Magnetoresistive film, 35b and 35c electrodes, 36 non-magnetic layer, 37 bias conductor, 38 upper shield core, 40 recording medium, Is sense current

Claims (7)

[Claims] 1. A multilayer magnetoresistive effect film having a multilayer film in which a magnetic layer and a non-magnetic conductor layer are laminated, with respect to a magnetic field in the x direction and a magnetic field in the y direction which are orthogonal to each other, with respect to a change in the magnetic field in the x direction. The multi-layered magnetoresistive device is characterized in that it exhibits a steep change in magnetic resistance even if the magnitude of the magnetic field is small, and exhibits a gentle change in magnetic field in the y direction while the magnitude of the magnetic field is small. Effect film. 2. The magnetic layer comprises a laminated film of Ni thin film and Fe thin film, a laminated film of Ni alloy thin film and Fe alloy thin film, Ni
A laminated film of a -Fe alloy thin film and a Ni-Fe alloy thin film,
2. The multilayer magnetoresistive film according to claim 1, wherein the Ni-Fe alloy thin film and the Ni-Fe alloy thin film are laminated films of Ni-Fe alloy thin films having different compositions. 3. The multilayer magnetoresistive effect film according to claim 1, wherein a magnetic layer thicker than the magnetic layer is provided above and below the multilayer film. 4. The magnetic layers disposed above and below the multilayer film are made of a NiFe-based alloy.
The multilayer magnetoresistive film described. 5. The non-magnetic conductor layer comprises Cu, Ag, A
2. The multilayer magnetoresistive effect film according to claim 1, containing at least one selected from u, Cu alloy, Ag alloy, and Au alloy. 6. Regarding a magnetic field in the x direction and a magnetic field in the y direction which are orthogonal to each other, a steep magnetic resistance change is exhibited with respect to the change in the magnetic field in the x direction even if the magnitude of the magnetic field is small, and a change in the magnetic field in the y direction occurs. On the other hand, the magnetoresistive effect element is characterized in that a multi-layered magnetoresistive effect film that exhibits a gradual magnetoresistive change while the magnitude of the magnetic field is small is used in at least a part thereof. 7. An x-direction magnetic field and a y-direction magnetic field which are orthogonal to each other exhibit a steep magnetoresistance change with respect to the x-direction magnetic field change even if the magnitude of the magnetic field is small, and the y-direction magnetic field change occurs. On the other hand, the magnetoresistive effect magnetic head is characterized in that a multi-layered magnetoresistive effect film that exhibits a gradual magnetoresistive change while the magnitude of the magnetic field is small is used in at least a part thereof.