JPH11232617A - Magnetoresistive effect element and magnetic head using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetoresistive effect element, in which the lowering of a switched-connection magnetic field and the increase of the coercive force of a second magnetic layer due to thermal disturbance or magnetic disturbance are inhibited and which has a spin valve type magnetoresistive effect film having the high switched- connection magnetic field and excellent thermal stability. SOLUTION: In the magnetoresistive effect element with a spin valve type magnetoresistive effect film using the four-layer structure of a free layer 3/a nonmagnetic layer 4/a pin layer 5/a magnetization fixing layer 6 as basic structure, the magnetization fixing layer 6 is composed of an antiferromagnetic-substance film and the pin layer 5 is formed in a three-layer laminated film. In the pin layer 5, a ferromagnetic-substance film 5a on the side brought into contact with the magnetization fixing layer 6 consists of a ferromagnetic-substance film, in which high switched- connection energy is obtained on an interface with the magnetization fixing layer 6, a central ferromagnetic-substance film 5b is made up of a ferromagnetic-substance film having saturation magnetization smaller than the ferromagnetic-substance film 5a and a ferromagnetic-substance film 5c adjacent to the nonmagnetic layer 4 is composed of a ferromagnetic-substance film being difficult to be mutually diffused between the nonmagnetic layer and the ferromagnetic-substance film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention comprises a spin-valve magnetoresistive film having a basic structure of a first magnetic layer (free layer) / non-magnetic layer / second magnetic layer (pin layer) / fixed magnetization layer. The present invention relates to a magnetic recording reproducing head utilizing a magnetoresistive effect, or a magnetoresistive element used for a magnetic sensor and a magnetic head using the same.

[0002]

2. Description of the Related Art In recent years, in a magnetic recording device such as a magnetic disk, there has been a demand for higher performance of a magnetic head along with an increase in recording density. Generally, reading of information recorded on a magnetic recording medium is performed by a method in which a reproducing magnetic head having a coil is relatively moved with respect to the medium and a voltage induced in the coil by electromagnetic induction is detected. Have been.

However, as the size and capacity of magnetic recording media have been reduced, the relative speed between the reproducing magnetic head and the magnetic recording media during information reading has been reduced. Therefore, the reproduction output does not depend on the relative speed of the magnetic head,
So-called MR heads utilizing the magnetoresistance effect, which can take out a large output even at a small relative speed, have been used.

As materials exhibiting such a magnetoresistive effect, thin films of Ni—Fe, Ni—Co and the like are well known, and the resistance change rate of these thin films is Ni—F
It is about 2 to 3% for the e film and about 6% at the maximum for the Ni—Co film. The magnetoresistance effect of such a thin film is due to the spin-orbit interaction and depends on the angle between the direction of the measured current and the magnetization direction of the magnetic material, and is usually called the anisotropic magnetoresistance effect (AMR). Have been.

On the other hand, recently, an artificial lattice film in which a magnetic thin film and a non-magnetic thin film are alternately laminated has been reported and has attracted attention because a resistance change rate that is one order of magnitude or more has been reported. The mechanism of the magnetoresistance effect of this artificial lattice thin film is different from that of the conventional AMR, and scattering of conduction electrons occurs when the magnetizations of the magnetic layers arranged above and below via the nonmagnetic layer of the artificial lattice film are antiparallel and parallel. A resistance change appears due to a large difference.

When the magnetization between the magnetic layers is antiparallel, the scattering of conduction electrons is large and the resistance value is high. On the other hand, when the magnetization between the magnetic layers is parallel, scattering decreases and the resistance value decreases.
The value of the resistance change at this time is much larger than that of the AMR, and is therefore called the giant magnetoresistance effect (GMR).

[0007] In a Co / Cu multilayer film, which is currently a material system showing the largest magnetoresistance change, a resistance change rate of 60% or more is obtained even at room temperature. However, although the rate of change of resistance in such an artificial lattice multilayer film is very large, the coupling between the magnetic layers is extremely large because the exchange interaction between the magnetic layers is used in order to realize an antiparallel state of magnetization without a magnetic field. Strongly, a magnetic field of several KOe to several hundreds Oe is required to break this exchange interaction and realize a parallel state of magnetization. For this reason, the sensitivity to a weak magnetic field is small, and it is insufficient for use as a magnetic recording head.

In order to improve the magnetic field sensitivity, a four-layer structure of a first magnetic layer (free layer) / non-magnetic layer / second magnetic layer (pinned layer) / fixed magnetization layer is provided in addition to the artificial lattice multilayer film. Are attracting attention.

FIG. 24 is a sectional view of a conventional spin-valve magnetoresistive film. In the magnetoresistive film, a first magnetic layer 33 made of a ferromagnetic film, a nonmagnetic layer 34, and a ferromagnetic film are formed on a substrate 31 made of glass via a base film 32 made of a Ta film or the like. A second magnetic layer 35 and a magnetization fixed layer 36 made of an antiferromagnetic material film are stacked in this order, and a protective film 37 made of a Ta film or the like is further formed thereon.

In the spin valve structure, the magnetization of the second magnetic layer 35 on one side made of a ferromagnetic film is formed by utilizing the exchange coupling between the second magnetic layer 35 and the magnetization fixed layer 36 made of an antiferromagnetic film. The sensitivity of the first magnetic layer 33 is improved by using a thin film having high softness such as Ni-Fe so that the magnetization of the other first magnetic layer 33 rotates freely with respect to a magnetic field.
This is the most practical structure. Hereinafter, the second magnetic layer 35 whose magnetization is fixed is referred to as a pinned layer 35, and the first magnetism 33 whose magnetization rotates freely is referred to as a free layer 33.

In this spin valve structure, the pin layer 3
The magnitude of the exchange coupling energy between the pinned layer 5 and the magnetization fixed layer 36 is determined by a combination of the interfaces between the pinned layer 35 and the magnetization fixed layer 36, and further, the magnitude of the exchange coupling energy depends on the total magnetization amount of the pinned layer 35. The magnitude of the coupling magnetic field is determined. Actually, an exchange coupling film that uses an antiferromagnetic material film for the magnetization fixed layer 36 and fixes the magnetization of the ferromagnetic film serving as the pinned layer 35 in one direction has been reported using various antiferromagnetic materials. The use of a Mn-based antiferromagnetic film such as an Fe-Mn film or a Pt-Mn alloy film has been reported well in the prior art.

[0012] For example, "Exchange-Coupl
ed Ni-Fe / Fe-Mn, Ni-Fe / Ni-M
n and NiO / Ni-Fe Fi1ms for
Stabilization of Magneto
-Resistive Sensors "
The Mn alloy film is also referred to as “Inproved exchan”
ge cupping between ferro
magnetic Ni-Fe and antife
rrmagnetic Ni-Fe-based f
i1ms "Appl. Phys. Lett. 65 (9)
1994 1183-1185 discloses an example using a MnNi alloy film.

Japanese Patent Application Laid-Open No. 3-314617 discloses that Mn contains Cu, Ru, Rh, and R as an antiferromagnetic film.
e, Ag, Au, Os, Ir at 25 to 76 at%, or Pd, Pt at 25 to 60 at% or 65 at%.
There is disclosed an example in which the addition of up to 76 at% improves the corrosion resistance and thermal stability of the antiferromagnetic material, and forms an exchange coupling film by laminating with a ferromagnetic film.

The Mn-based antiferromagnetic film includes Fe—Mn,
An irregular alloy capable of obtaining an exchange coupling magnetic field without heat treatment such as Ir-Mn or Rh-Mn;
There are ordered alloys, such as n and Ni-Mn, in which an exchange coupling magnetic field can be obtained only by performing a heat treatment at 230 to 255 ° C. after film formation.

As a typical example of a Mn-based disordered alloy, F
In the case of using e-Mn, the exchange coupling magnetic field decreases with increasing temperature, and disappears at about 150 ° C.
That is, at about 150 ° C., Fe—Mn loses antiferromagnetism. This temperature is called a blocking temperature (Tb). As described above, in Fe-Mn, Tb is as low as about 150 ° C., and the exchange coupling magnetic field monotonously decreases with the temperature.
When -Mn is applied to a magnetoresistive element, it is necessary to keep the operating temperature of the element at a low temperature.

Further, in the exchange-coupling film using this Fe-Mn, the exchange-coupling magnetic field is greatly reduced by a temperature raising / lowering process (thermal history). For this reason, when manufacturing a magnetoresistive element or a thin film magnetic head using Fe—Mn for the exchange coupling film, it is necessary to always control the process temperature to a low temperature. This leads to a reduction in the structural reliability and productivity of the thin film head.

In addition, Fe-Mn has poor corrosion resistance, and there is a danger that the characteristics of the element and the thin film head are greatly deteriorated in the use environment. Therefore, it is difficult to apply these materials to manufacture a magnetic device having excellent magnetic characteristics and reliability.

On the other hand, a Mn-based ordered alloy typified by Pt—Mn is formed by using a magnetization fixed layer 3 having a spin valve structure.
When used as 6, Tb is as high as about 380 ° C., and the exchange coupling magnetic field maintains a high value up to about 300 ° C. Also,
A high exchange coupling magnetic field is obtained stably with respect to the thermal history.

As an example of a spin valve film in which a Pt-Mn film is actually used for the magnetization fixed layer 36, there is the example of Journal of the Japan Society of Applied Magnetics, Vo121, No. 4-2, 1997, 505-508. In this report, the Ni-F
Experimental results using an e single layer film and a Co single layer film have been reported. However, it is 235 to 2 to generate the exchange coupling magnetic field.
Since long-time annealing at a high temperature of 55 ° C. is required, heat resistance of other parts of the element is required.

Further, examples of using a Ni—Fe-based alloy, a Co alloy, and a Co—Fe-based alloy as the pin layer 35 having the spin valve structure are well reported. When the GMR element is actually manufactured, the free layer 33 and the pinned layer 3 are used in the spin valve structure.
The magnetoresistive effect is generated by the angle formed by the direction of magnetization with 5, and a reproduction output is obtained. Therefore, in order to obtain a stable reproduction output with respect to a magnetic disturbance, it is necessary that the magnetization direction of the pinned layer 35 always be in a fixed direction with respect to the magnetic disturbance.

That is, in order to manufacture an element capable of obtaining a reproduction output stably thermally and magnetically, the exchange coupling magnetic field and the coercive force should be as high as possible, that is, the difference between the exchange coupling magnetic field and the coercive force should be large. This is a necessary condition.

In order to obtain a high exchange coupling magnetic field, it is conceivable to reduce the total magnetization of the pinned layer 35. Pin layer 3
As a method of reducing the total amount of magnetization of No. 5, a method of simply reducing the film thickness or a method of separating a ferromagnetic layer by an antiferromagnetic coupling film as disclosed in Japanese Patent Application Laid-Open No. There has been reported a method in which a ferromagnetic film is formed by a laminated film.

[0023]

As described above, the spin valve structure has a free layer 33 whose magnetization direction rotates in response to an external magnetic field, a non-magnetic layer 34, and a magnetization direction fixed in one direction. The pinned layers 35 are arranged in this order, and a magnetoresistive effect is generated by the angle between the magnetization directions of the free layer 33 and the pinned layer 35 to obtain a reproduction output.

At this time, if the magnetic characteristics of the free layer 33 and the pinned layer 35 are the same, the magnetization of the free layer 33 and the pinned layer 35 are simultaneously rotated by the external magnetic field, and the free layer 33 and the pinned layer 35 are rotated. An angle does not occur in the direction of magnetization, and the magnetoresistance effect cannot be obtained.

For this purpose, a pinned layer 36 made of an antiferromagnetic film is laminated on the pinned layer 35, and the magnetization of the pinned layer 35 is changed in one direction by the exchange coupling magnetic field between the pinned layer 35 and the pinned layer 36. The magnetoresistance effect can be obtained by fixing the angle and by causing an angle between the magnetization of the free layer 33 and the magnetization of the pinned layer 35.

Therefore, when the exchange coupling magnetic field is small, the magnetization of the pinned layer 35 is easily rotated by the disturbance magnetic field, and the output from the signal magnetic field cannot be stably obtained. When the coercive force of the pinned layer 35 is increased and the difference from the exchange coupling magnetic field is reduced, the magnetization of the pinned layer 35 is rotated once by a large disturbance magnetic field, and then the direction of the magnetization of the pinned layer 35 in the operating magnetic field. Changes, and stable magnetoresistance effect characteristics cannot be obtained. In other words, in order to manufacture an element capable of obtaining a read output stably thermally and magnetically, the exchange coupling magnetic field and the coercive force should be as high as possible.
That is, it is necessary that the difference between the exchange coupling magnetic field and the coercive force is large.

In the above-described spin valve film using Pt-Mn for the magnetization fixed layer 36, Ni-F
When the e single layer film and the Co single layer film are used, the coercive force of the pinned layer 35 can be suppressed small in the Ni—Fe single layer film,
The exchange coupling energy with the Pt-Mn antiferromagnetic film is small, while the exchange coupling energy with the Pt-Mn antiferromagnetic film is large in the Co single layer film, but the exchange coupling energy is large due to the large saturation magnetization of the Co film. The magnetic field is small, and the coercive force of the pinned layer 35 increases.

As a result, in both cases, the difference between the exchange coupling magnetic field and the coercive force becomes small, which is insufficient for actually using as a head.

In order to obtain a high exchange coupling magnetic field,
Although it is required to reduce the total magnetization of the pin layer 35,
Simply reducing the film thickness will be described in detail later, but as the film thickness decreases, the increase in the coercive force exceeds the increase in the exchange coupling magnetic field, and the difference between the exchange coupling magnetic field and the coercive force is reversed. It will be smaller.

Further, as disclosed in Japanese Patent Application Laid-Open No. Hei 7-169026, in the method in which the pinned layer 35 is constituted by a laminated film of two ferromagnetic films separated by an antiferromagnetic coupling film, Since the film thickness at which antiferromagnetic coupling occurs is limited to a very narrow range and is very thin, it is difficult to stably generate antiferromagnetic coupling.

According to the present invention, a high exchange coupling magnetic field and a low coercive force can be stably obtained by devising the structure of the second magnetic layer (pin layer) in which the magnetization is fixed in the spin valve type magnetoresistive film. And a magnetic head using the same.

[0032]

As described above, in order to produce a magnetoresistive film that is stable against disturbances caused by magnetic fields and heat, the exchange coupling magnetic field must be as large as possible and the difference from the coercive force must be large. Is required.

In order to achieve the above object, the magnetoresistive element according to claim 1 of the present invention has a four-layer structure of a first magnetic layer / nonmagnetic layer / second magnetic layer / fixed magnetization layer as a basic structure. In the magnetoresistive element having a spin valve type magnetoresistive film, the magnetization fixed layer is formed of an antiferromagnetic film, while the second magnetic layer is formed of two or more ferromagnetic films. In the multilayer film, the layer on the side in contact with the magnetization fixed layer is formed of a ferromagnetic film in which high exchange coupling energy is obtained at the interface with the magnetization fixed layer, and other than the layer on the side in contact with the magnetization fixed layer. It is characterized in that the layer includes a layer made of a ferromagnetic film having a small saturation magnetization.

In the magnetoresistance effect element having such a configuration,
First, a high exchange coupling magnetic field can be obtained in a ferromagnetic film that is in contact with the magnetization fixed layer in the second magnetic layer and that can obtain higher exchange coupling energy at the antiferromagnetic film interface of the magnetization fixed layer. Further, the saturation magnetization of the second magnetic layer itself can be reduced by the ferromagnetic film having a low saturation magnetization used in other portions.

As a result, a high exchange coupling magnetic field can be obtained while keeping the coercive force low as compared with the conventional configuration, and the difference between the exchange coupling magnetic field and the coercive force increases. Thus, a magnetoresistance effect element having high stability can be realized.

According to a second aspect of the present invention, there is provided the magnetoresistive element according to the first aspect, wherein the layers other than the layer in contact with the magnetization fixed layer in the multilayer film constituting the second magnetic layer are:
It is characterized by being a multilayer film of a layer made of a ferromagnetic film having a small saturation magnetization and a layer made of a ferromagnetic film different from the ferromagnetic film.

According to this, since the second magnetic layer other than the layer in contact with the fixed magnetization layer has a multilayer structure including a ferromagnetic film having a small saturation magnetization, the magnetization reversal modes are uniform and the magnetic domain is uniform. There is an effect that the disorder of the structure is suppressed and an excellent magnetoresistance effect is obtained.

According to a third aspect of the present invention, there is provided a magnetoresistive element according to the first or second aspect, wherein a layer on the side of the multilayer film constituting the second magnetic layer which is in contact with the nonmagnetic layer is a nonmagnetic layer. And a ferromagnetic film that does not easily diffuse between them.

According to this, since the thermal diffusion between the second magnetic layer and the non-magnetic layer is reduced, the decrease in the magnetoresistance ratio (MR ratio) due to the thermal diffusion is suppressed, and the magnetoresistance change is suppressed. The rate can be increased.

A magnetoresistive element according to a fourth aspect of the present invention, in the structure according to any one of the first to third aspects, comprises a ferromagnetic film having a small saturation magnetization in the multilayer film forming the second magnetic layer. The layer is characterized in that the layer thickness is larger than the other layers in the multilayer film.

By making the layer made of a ferromagnetic film having a small saturation magnetization thicker than other ferromagnetic films constituting the second magnetic layer, the total amount of magnetization of the second magnetic layer itself can be effectively reduced. Can be reduced.

According to a fifth aspect of the present invention, in the magnetoresistance effect element according to any one of the first to fourth aspects, the magnetization fixed layer is made of a Mn-based antiferromagnetic ordered alloy film, and The heat treatment during the magnetization is performed after the second magnetic layer and the magnetization fixed layer are stacked.

The Mn-based antiferromagnetic ordered alloy has a higher blocking temperature at which the Mn-based antiferromagnetic disordered alloy loses antiferromagnetism, maintains a high value of the exchange coupling magnetic field up to about 300 ° C., and reduces heat history. On the other hand, since a high exchange coupling magnetic field can be obtained stably and strongly, it is preferable to use as an antiferromagnetic film of the magnetization fixed layer.

Hereinafter, claims 6 to 11 are requirements for realizing the magnetoresistance effect element of the present invention when a Mn-based antiferromagnetic ordered alloy is used for the magnetization fixed layer.

As described in claim 6 of the present invention, Mn
As the ordered antiferromagnetic alloy, a PtMn alloy film or a PdPtMn alloy film can be used. As described in claim 7 of the present invention, the PtMn alloy film or the PdPtMn alloy film used for the magnetization fixed layer is used. The layer thickness of the layer is
The angle may be 150 ° or more.

Further, as described in claim 8 of the present invention, when a Mn-based antiferromagnetic ordered alloy is used for the magnetization fixed layer, the layer of the second magnetic layer that is in contact with the magnetization fixed layer is:
It may be made of a Co-based alloy film such as a Co film or a CoFe film, and further, as described in claim 9 of the present invention, a Co film constituting a layer of the second magnetic layer on the side in contact with the magnetization fixed layer. Alternatively, the thickness of the layer made of the Co-based alloy film may be 5 ° or more.

Further, when the Mn-based antiferromagnetic ordered alloy is used for the magnetization fixed layer as described in claim 10 of the present invention, the ferromagnetic material having a small saturation magnetization in the multilayer film forming the second magnetic layer. As the film layer, a NiFe alloy film can be used.

Further, when the Mn-based antiferromagnetic ordered alloy is used for the magnetization fixed layer as described in claim 11 of the present invention, the ferromagnetic material having a small saturation magnetization in the multilayer film forming the second magnetic layer. The film layer may be configured to include a multilayer film of a layer made of a NiFe alloy film and a layer made of a Co film.

According to a twelfth aspect of the present invention, in the magnetoresistance effect element according to any one of the third to eleventh aspects, the layer made of a ferromagnetic film which is hardly interdiffused with the nonmagnetic layer is provided. , Co film, or a Co-based alloy film such as a CoFe alloy film.

In the multilayer film constituting the second magnetic layer according to claim 3, a layer made of a ferromagnetic film which is in contact with the non-magnetic layer and which is not easily diffused with the non-magnetic layer is specifically shown. The layer can be easily realized by a Co film or a Co alloy film such as a CoFe film. In the case where a Mn-based antiferromagnetic ordered alloy is used for the magnetization fixed layer, the thickness of the Co film or the layer made of the Co-based alloy film may be 5 ° or more. .

According to a fourteenth aspect of the present invention, there is provided the magnetoresistive element according to any one of the fourth to thirteenth aspects, wherein the nonmagnetic layer comprises a Cu film and has a thickness of 28 °.
Å36 °.

This shows the specific structure of the nonmagnetic layer. When a Mn-based antiferromagnetic ordered alloy is used for the magnetization fixed layer, the thickness of the nonmagnetic layer made of Cu is set to 28 ° to 36 °.
The required sensitivity of the magnetoresistive film can be obtained.

According to a fifteenth aspect of the present invention, there is provided the magnetoresistive element according to any one of the first to fourteenth aspects, wherein the spin-valve type magnetoresistive film controls the orientation on the substrate so that the crystallinity is improved. Is provided via a base layer for improving

By forming the magnetoresistance effect element according to the present invention as described above by forming it through the underlayer, the above-mentioned magnetoresistance effect element of the present invention can be stably obtained.

A magnetic head according to a sixteenth aspect of the present invention provides:
16. A magnetoresistive element according to claim 1, energizing means for supplying a current to said magnetoresistive element, and a magnitude of a magnetic field corresponding to magnetic information recorded on a magnetic recording medium. Detecting means for detecting the electrical resistance of the magnetoresistive element which changes as a result.

As a result, it is excellent in thermal stability and magnetic field stability, and can maintain a high magnetoresistance effect characteristic even in a high-temperature heat treatment process in a head manufacturing process or a thermal and magnetic disturbance under actual use conditions. It is possible to provide a highly reliable magnetic head.

[0057]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.

As shown in FIG. 1, a spin-valve type magnetoresistive film (hereinafter abbreviated as a magnetoresistive effect film) of this embodiment is provided on a substrate 1 made of glass or the like, as an underlayer (underlayer) 2. , A first magnetic layer 3 / non-magnetic layer 4 / second magnetic layer 5 / fixed magnetization layer 6 are laminated in this order, and a protective film 7 is formed thereon.

The magnetization fixed layer 6 is made of an antiferromagnetic film,
The magnetization of the adjacent second magnetic layer (hereinafter, referred to as a pinned layer) 5 is fixed in one direction by an exchange coupling magnetic field acting on an interface between the magnetization fixed layer 6 and the pinned layer 5. As the magnetization fixed layer 6, for example, a Mn-based antiferromagnetic film can be used.

The Mn-based antiferromagnetic material includes Fe—Mn (Fe
Mn alloy: hereinafter, the alloy is represented by-), Ir-Mn, Rh
-An exchange alloy which can obtain an exchange coupling magnetic field without heat treatment like Mn, and an exchange coupling magnetic field only by heat treatment at 230 to 255 ° C after film formation like Pt-Mn or Ni-Mn. And an ordered alloy that gives

Any of them can be used. However, the Mn-based disordered alloy has the drawback that the exchange coupling magnetic field decreases as the temperature rises and the blocking temperature (Tb) at which antiferromagnetism is lost is low. It is preferable to use a systematic alloy. When the Mn-based ordered alloy has a high Tb and the exchange coupling magnetic field is also Pt-Mn, a high value is maintained up to about 300 ° C., and a high exchange coupling magnetic field is obtained stably with respect to the heat history. However, as described above, since long-time annealing at a high temperature of 235 to 255 ° C. is required to generate the exchange coupling magnetic field, heat resistance of other parts of the element is required.

The pinned layer 5 is made of a ferromagnetic film, and has a three-layer structure of a first ferromagnetic film 5a, a second ferromagnetic film 5b, and a third ferromagnetic film 5c.

The first ferromagnetic film 5 a in contact with the magnetization fixed layer 6 is a ferromagnetic film having a high exchange coupling energy at the interface with the antiferromagnetic film used for the magnetization fixed layer 6. Consists of a body membrane. For example, Pt-
When a Mn-based ordered alloy film such as a Mn film is used,
A Co film is used. On the other hand, Fe-Mn
When a Mn-based disordered alloy film such as a film is used, N
An i-Fe film is used. Thereby, the exchange coupling magnetic field between pinned layer 5 and magnetization fixed layer 6 increases.

The second ferromagnetic film 5b at the center is made of a ferromagnetic film having a smaller saturation magnetization than the first ferromagnetic film 5a in contact with the magnetization fixed layer 6. For example, when a Mn-based ordered alloy film such as a Pt—Mn film is used for the magnetization fixed layer 6 and the first ferromagnetic film 5a is a Co film, the second ferromagnetic film 5b is more saturated than the Co film. A Ni—Fe film having a small magnetization is used. Thereby, the total magnetization amount of the pinned layer 5 itself can be reduced.

The third pin layer 5 in contact with the nonmagnetic layer 4
As the ferromagnetic film 5c, a ferromagnetic film hardly interdiffused to prevent interdiffusion with the nonmagnetic layer 4 is used. Thereby, a decrease in the MR ratio due to thermal diffusion between the pinned layer 5 and the nonmagnetic layer 4 can be suppressed.

Here, although the pinned layer 5 is a three-layer laminated film, a high exchange coupling energy is provided on the side in contact with the magnetization fixed layer 6 at the interface with the antiferromagnetic film used for the magnetization fixed layer 6. Is provided, and a first ferromagnetic film 5a is obtained, and
The other portions only need to include the second ferromagnetic film 5b having a smaller saturation magnetization than the first ferromagnetic film 5a, and the first ferromagnetic film 5a and the second ferromagnetic film 5b May be used. Therefore, the second ferromagnetic film 5b may have a multilayer structure with other ferromagnetic films. However, the multi-layer structure has the advantage that the number of interfaces increases, the magnetization reversal modes are uniform, and the magnetoresistance effect is more likely to appear than the single-layer structure.

Further, the second ferromagnetic film 5b made of a ferromagnetic film having a smaller saturation magnetization than the first ferromagnetic film 5a
In order to reduce the saturation magnetization of the pinned layer 5 itself, other ferromagnetic films (the first and third ferromagnetic films 5
a, 5c, or other ferromagnetic films).

The non-magnetic layer 4 is made of a non-magnetic film such as a Cu film, for example, and includes a first magnetic layer (hereinafter, a free layer) 3 and a pinned layer 5.
And to separate them.

The free layer 3 is made of a ferromagnetic film, and has a two-layer structure of a ferromagnetic film 3a and a ferromagnetic film 3b. As the ferromagnetic films 3a and 3b, C
o, a thin film of Ni—Fe or the like is used.

The base film 2 is not always necessary, but is used to control the orientation when forming a thin film in order from the free layer 3 on the glass substrate 1 and to improve the crystallinity.
A thin film of a, Ti, Cr or the like can be used. As the protective film 7, a Ta film or the like is used.

In the magnetoresistance effect film having such a configuration, the first ferromagnetic film 5 in contact with the magnetization fixed layer 6 in the pinned layer 5
For a, use is made of a ferromagnetic film capable of obtaining higher exchange coupling energy at the antiferromagnetic film interface of the magnetization fixed layer 6, and
Since the second ferromagnetic film 5b is a ferromagnetic film having a lower saturation magnetization than the first ferromagnetic film 5a, a high exchange coupling magnetic field can be obtained while keeping the coercive force low as compared with the related art. be able to.

In addition, in the magnetoresistive effect film of the present embodiment, the third ferromagnetic film 5c in contact with the nonmagnetic layer 4 in the pinned layer 5 has little heat diffusion with the nonmagnetic layer 4 and has an MR ratio. Since the ferromagnetic film which becomes large is used, thermal diffusion with the nonmagnetic layer 4 can be suppressed, and the MR ratio can be further increased.

As a result, in the magnetoresistive film of this embodiment, a large difference between the exchange coupling magnetic field and the coercive force realizes a magnetoresistive element having high stability against magnetic fields and thermal disturbances. can do.

When a magnetoresistive element having the above-described magnetoresistive film is applied to a magnetic head, it has excellent thermal stability and magnetic field stability. It is possible to provide a highly stable magnetic head that can maintain high magnetoresistance effect characteristics even against thermal and magnetic disturbances.

FIGS. 2 and 3 show a magnetoresistive element having the magnetoresistive film. In the figure, reference numeral 21 denotes a magnetoresistive film, and the magnetoresistive film 21 and the electrodes 22.2
2 is sandwiched between shield layers 23 and 24. In the magnetoresistive element of FIG. 3, the free layer 3 (see FIG. 1) in the magnetoresistive film 21 is made into a single magnetic domain in order to suppress Barkhausen noise caused by the movement of the domain wall.
5 and 25 are further provided. The above electrode 22
For example, a Ta / Cu / Ta laminated film can be used for 22. For the magnetic domain control layers 25, for example, Co-Pt can be used.

The electrode 22 of such a magneto-resistance effect element
And a detecting means for detecting an electric resistance of the magnetoresistive element which changes in accordance with the magnitude of a magnetic field corresponding to magnetic information recorded on a magnetic recording medium. (Not shown), a magnetic head is realized.

[0077]

[Embodiment 1] In Embodiment 1, a Ru—Mn film made of a Mn-based disordered alloy is used as the antiferromagnetic film of the magnetization fixed layer.
A conventional spin-valve magnetoresistive film using a single-layer film of Co or Ni—Fe as the ferromagnetic film of the pin layer and the pin layer 5 according to the present invention shown in FIG. A spin-valve type magnetoresistive film using a layer laminated film was prepared, and the dependence of the exchange coupling magnetic field and the coercive force on the pin layer thickness was compared.

First, the conventional magnetoresistive film shown in FIG. 24 is replaced with a pinned layer 3 using a Ru—Mn film as the magnetization fixed layer 36.
5, a Ni—Fe single-layer film and a Co single-layer film were used.

FIG. 4 shows the dependence of the exchange coupling magnetic field and the coercive force on the thickness of the pinned layer 35 in the sample using the Co single layer film as the ferromagnetic film and in FIG. 5 on the sample using the Ni—Fe single layer film. Shows sex. In the case of a Co single layer film, as shown in FIG. 4, the increase in coercive force exceeds the increase in exchange coupling as the film thickness decreases, and the difference between the exchange coupling magnetic field and the coercive force becomes smaller on the contrary. I understand. Also, when the pinned layer 35 is a Ni—Fe single layer film, as shown in FIG.
o It is almost the same as the case of a single layer film.

Here, from the value of the exchange coupling magnetic field, the saturation magnetization of the Co single layer film and the saturation magnetization of the Ni—Fe single layer film are each 1350 em.
When the exchange coupling energy was calculated as u / cm ³ and 780 emu / cm ^3, as shown in Table 1, the Co single layer film was 0.0
7 erg / cm ² , Ni—Fe single layer film is 0.11 erg / cm ²
Met.

[0081]

[Table 1]

Thus, when the Ru—Mn film is used as the antiferromagnetic film of the magnetization fixed layer 36, N
It was found that the i-Fe film had higher exchange coupling energy.

Therefore, when the pinned layer 5 in the magnetoresistive effect film according to the present invention of this embodiment has a three-layer laminated structure, the first, second, and third ferromagnetic materials are arranged from the magnetization fixed layer 6 side. Film order) and a three-layer laminated film of Ni—Fe / Ni—Fe—Nb / Co. The procedure for forming the magnetoresistive film will be described below.

First, a base film 2 made of Ta is formed on a glass substrate 1, and a ferromagnetic film 3b made of a Ni—Fe film, a ferromagnetic film 3a made of a Co film, and a Cu film are formed thereon. A non-magnetic layer 4, a third ferromagnetic film 5c made of a Co film, and a second ferromagnetic film 5 made of a Ni—Fe—Nb film
(b) After laminating the first ferromagnetic film 5a made of a Ni-Fe film, a magnetization fixed layer 6 made of a Ru-Mn film and a protective film 7 made of Ta were laminated.

At this time, from the base film 2 to the protective film 7, a single film forming apparatus was used to evacuate to 5 × 10 ⁻⁸ Torr or less, and then a continuous film was formed in the same vacuum without breaking the vacuum. . Cu film of the nonmagnetic layer 4 and Ru of the magnetization fixed layer 6
-The Mn film is formed using a DC magnetron sputtering method, and the Ta film of the base film 2 and the protective film 7 and the Co film of the third ferromagnetic film 5c and the ferromagnetic film 3a are formed by RF magnetron sputtering. N of the first ferromagnetic film 5a and the second ferromagnetic film 5b
The i-Fe film and the Ni-Fe-Nb film were formed by using RF conventional sputtering.

The thickness of each layer is as follows: base film 2 = 50 °, ferromagnetic film 3b = 70 °, ferromagnetic film 3a = 7 °, nonmagnetic layer 4
= 28 °, third ferromagnetic film 5c = 10 °, second ferromagnetic film 5b = 30 to 100 °, first ferromagnetic film 5a = 5 °,
The magnetization fixed layer 6 was set to 120 °. In this embodiment, the Ru composition of the magnetization fixed layer 6 is set to be constant at about 18 at%,
The Nb composition of the -Fe-Nb film was about 2 at%.

At this time, the saturation magnetization of the Ni—Fe—Nb film is 660 emu / cm ³ , and the total magnetization of the entire pinned layer 5 is Ni—
The value was 0.89 when the Fe / Co two-layer laminated film was 1.0. The soft magnetic characteristics of the entire pinned layer 5 were hardly degraded, and the coercive force maintained a value of 1 to 3 Oe.

FIG. 6 shows that the pinned layer 5 is
The graph shows the dependence of the exchange coupling magnetic field and the coercive force on the thickness of the pinned layer 5 (second ferromagnetic film 5b) when a three-layered film of Ni-Fe / Ni-Fe-Nb / Co is used. Thus, when the three-layered film of Ni—Fe / Ni—Fe—Nb / Co is used for the pinned layer 5, the absolute values of the exchange coupling magnetic field and the coercive force are:
The Ni—Fe single layer film shown in FIG.
It turns out that it is larger than the case where the single layer film is used. However, the increase in the coercive force due to the decrease in the thickness of the pinned layer 5 is suppressed to be lower than when the Ni—Fe single-layer film or the Co single-layer film is used. As a result, the exchange coupling magnetic field and the coercive force are reduced. It can be seen that the difference is larger.

In this embodiment, the substrate 1 and the free layer 3
In between, the underlayer 2 made of a Ta film is used to orient the free layer 3 in the (111) plane and improve the crystallinity, but the effect of the present invention can be obtained even when the underlayer 2 is not used. Was similarly obtained.

[Embodiment 2] In Embodiment 2, the second ferromagnetic film 5b of the pinned layer 5 in the magnetoresistive effect film of Embodiment 1 is used.
Was used as a Ni—Fe—X (X = Nb, Zr, Cr) film to reduce the total magnetization of the pinned layer 5 and to examine changes in the exchange coupling magnetic field and the coercive force.

The amount of each additive element was adjusted by arranging pellets on a Ni—Fe target and changing the number thereof. As for the film forming method, the first embodiment
A film is formed in the same manner as described above, and Ni is deposited from the magnetization fixed layer 6 side.
-Fe / Ni-Fe-X / Co has a three-layered film thickness of:
5 ° / 50 ° / 10 °.

FIG. 7 shows the values of the saturation magnetization of the entire pinned layer 5 when each additive element is added. From this, Nb, Zr,
It can be seen that the saturation magnetization decreases in the order of Cr. When Nb, Zr, and Cr are added to the Ni—Fe film,
The soft magnetic properties of each film hardly deteriorated, and the coercive force was 1 to 3
The value of Oe was kept.

FIGS. 8 to 10 show actually the second layer of the pinned layer 5.
Nb, Zr, Cr are added to Ni-Fe-X of the ferromagnetic film 5b.
3 shows changes in the exchange coupling magnetic field and the coercive force in the case where is added. From this, it can be seen that the exchange coupling magnetic field increases with an increase in the addition amount, that is, a decrease in the total magnetization amount of the pinned layer 5, regardless of which addition element is added to Ni-Fe.

At this time, the increase in the coercive force of the pinned layer 5 is suppressed to be lower than when a single-layer film of Co or a single-layer film of Ni—Fe is used, and a low coercive force and a high exchange coupling magnetic field are reduced. It can be seen that the magnetoresistive effect film having the above is realized.
In addition, the MR ratio was maintained at a value of approximately 6.0 to 6.5% irrespective of the amount of the additional element such as Nb, Zr, or Cr.

Embodiment 3 In Embodiment 3, a Pt—Mn film of a Mn-based ordered alloy was used for the antiferromagnetic film of the magnetization fixed layer.
A conventional spin-valve magnetoresistive film using a single-layer film of Co or Ni—Fe as the ferromagnetic film of the pin layer and the pin layer 5 according to the present invention shown in FIG. A spin-valve type magnetoresistive film using a layer laminated film was prepared, and the dependence of the exchange coupling magnetic field and the coercive force on the pin layer thickness was compared.

First, the conventional magnetoresistive film shown in FIG. 24 is replaced with a pinned layer 35 using a Pt-Mn film as the magnetization fixed layer 36.
Was formed using a single-layer film of Ni—Fe and a single-layer film of Co.

FIG. 11 shows a sample using a Ni—Fe single layer film as a ferromagnetic film, and FIG. 12 shows a sample using Co as a ferromagnetic film.
4 shows the pin-layer thickness dependence of the exchange coupling magnetic field and coercive force of a sample using a single-layer film. Thus, when a single-layer film of Ni—Fe is used, as shown in FIG. 11, the increase in coercive force exceeds the increase in exchange coupling as the film thickness decreases, and the difference between the exchange coupling magnetic field and the coercive force is It turns out that it becomes small. Also, as shown in FIG. 12, when the pinned layer 35 is a single-layer film of Co, the absolute value of each is large, but the dependency on the film thickness is almost the same as that of the Ni-Fe film.

Here, when the exchange coupling energy was calculated in the same manner as in Example 1, as shown in Table 1, the Co single layer film was 0.29 erg / cm ² , and the Ni—Fe single layer film was 0.15 erg / cm ² .
/ Cm ² , and the antiferromagnetic film of the magnetization fixed layer 36 has Pt-
It was found that when a Mn film was used, the Co film had a higher exchange coupling energy.

Therefore, when the pinned layer 5 of the magnetoresistive effect film according to the present invention of this embodiment is formed as a three-layer laminated film, a three-layer laminated film of Co / Ni—Fe / Co is formed from the magnetization fixed layer 6 side. .

In this embodiment, the magnetoresistive effect film is formed in the same manner as in the first embodiment.
50 °, ferromagnetic film 3b = 70 °, ferromagnetic film 3a = 7
{, Nonmagnetic layer 4 = 28}, third ferromagnetic film 5c = 10
Å, the second ferromagnetic film 5b = 30〜100 °, the first ferromagnetic film 5a = 5Å, and the magnetization fixed layer 6 = 200Å.
In this embodiment, the Pt composition in the magnetization fixed layer 6 is about 4%.
Annealing for generating the exchange coupling magnetic field was performed at 250 ° C. for 6 hours while applying a magnetic field of 300 Oe.

FIG. 13 shows a case where a three-layer laminated film of Co / Ni—Fe / Co is used as the pinned layer 5 from the magnetization fixed layer 6 side.
The pin layer 5 (the second ferromagnetic film 5) having the exchange coupling magnetic field and the coercive force.
b) Dependence on film thickness. Thus, Co / N is applied to the pin layer 5.
In the case of using a three-layer laminated film of i-Fe / Co, the absolute values of the exchange coupling magnetic field and the coercive force are determined by using the Ni-Fe single-layer film shown in FIG. 11 or the Co single-layer film shown in FIG. It turns out that it is large compared with. However,
The increase in the coercive force due to the decrease in the thickness of the pinned layer 5 is suppressed to be lower than in the case of using the Ni—Fe single layer film or the Co single layer film. As a result, the difference between the exchange coupling magnetic field and the coercive force is reduced. You can see that it is getting bigger.

In this embodiment, the substrate 1 and the free layer 3
In between, the underlayer 2 made of a Ta film is used to orient the free layer 3 in the (111) plane and improve the crystallinity, but the effect of the present invention can be obtained even when the underlayer 2 is not used. Was similarly obtained.

[Fourth Embodiment] In the fourth embodiment, the magnetization fixed layer 6
The second ferromagnetic film 5b of the pinned layer 5 in the magnetoresistive effect film of the third embodiment, similarly to the second embodiment, using a Pt—Mn film
Nb, Zr, and Cr were added to Ni-Fe of
The change in the exchange coupling magnetic field and the coercive force when the total magnetization was reduced was examined.

The magnetoresistive film according to the present invention of this embodiment is formed by the same method as in the first and second embodiments.
From the side of the magnetization fixed layer 6, the thickness of the three-layered film of Co / Ni—Fe—X / Co was 5 ° / 50 ° / 10 °. Also,
Annealing for developing the exchange coupling magnetic field was performed in the same manner as in Example 3 while applying a magnetic field of 300 Oe and at 250 ° C. for 6 hours.

FIGS. 14 to 16 show the second ferromagnetic film 5b.
The change of the exchange coupling magnetic field and the coercive force when Nb, Zr, and Cr were added to Ni-Fe of No. 1 were shown. Thus, when the Pt—Mn film is used as the antiferromagnetic film of the magnetization fixed layer 6, similarly to the case where the Ru—Mn film is used, Ni—
It can be seen that regardless of which additive element is added to Fe, the exchange coupling magnetic field increases as the amount of addition increases, that is, as the total magnetization of the pinned layer 5 decreases. At this time, the increase in the coercive force of the pinned layer 5 is suppressed to be lower than in the case of using a single-layer Co film or a single-layer Ni—Fe film. It can be seen that a resistance effect film has been realized.

Further, regarding the MR ratio, Nb, Zr, Cr
5.5 to 6.0 regardless of the amount of the additional element
% Value was maintained.

[Embodiment 5] In this embodiment, the magnetization fixed layer 6
The necessity of the first ferromagnetic film 5a in contact with the magnetization fixed layer 6 in the pinned layer 5 was examined while using a Mn-based ordered alloy to improve the temperature characteristics of the exchange coupling magnetic field.

Here, a base film 2 made of a Ta film is formed on a glass substrate 1, and a ferromagnetic film 3b made of a Ni—Fe film, a ferromagnetic film 3a made of a Co film, and a Cu film are formed thereon. Non-magnetic layer 4, a third ferromagnetic film 5 c made of a Co film, and a second ferromagnetic film 5 made of a Ni—Fe film
b, after laminating the first ferromagnetic film 5a made of a Co film,
A sample # 1 was prepared by stacking a magnetization fixed layer 6 made of a Pt-Mn film and a protective film 7 made of a Ta film.

At this time, from the base film 2 to the protective film 7, after evacuation was performed to 5 × 10 ⁻⁸ Torr or less by using a single film forming apparatus, continuous lamination was performed in the same vacuum without breaking the vacuum. . Cu film of the nonmagnetic layer 4 and Pt of the magnetization fixed layer 6
The Mn film is formed by using a DC magnetron sputtering method, and the Ta film of the base film 2 and the protective film 7 and the ferromagnetic film 3a
The Co films of the first and third ferromagnetic films 5a and 5c are formed by RF magnetron sputtering, and the Ni—Fe films of the ferromagnetic film 3b and the second ferromagnetic film 5b are formed by RF conventional sputtering. A film was formed.

The thickness of each layer is as follows: base film 2 = 50 °, ferromagnetic film 3b = 70 °, ferromagnetic film 3a = 7 °, nonmagnetic layer 4
= 28 °, third ferromagnetic film 5c = 10 °, second ferromagnetic film 5b = 30 to 100 °, first ferromagnetic film 5a = 5 °,
The magnetization fixed layer 6 was set to 200 °. In this embodiment, the Pt composition of the magnetization fixed layer 6 is set to be constant at about 48 at%, and annealing is performed in a vacuum while applying a magnetic field of 300 Oe.
C. for 6 hours.

For comparison, the first ferromagnetic film 5 made of a Co film in contact with the magnetization fixed layer 6 in the pinned layer 5 is used.
Sample # 2 was prepared with the thickness of a set to 0 °.

FIG. 17B shows a second structure made of a Ni—Fe film.
When the ferromagnetic film 5b is set at 50 °, there is a first ferromagnetic film 5a made of a Co film (sample # 1), and when the first ferromagnetic film 5a is not shown in FIG. (Sample # 2) shows the magnetization curve thereof. From FIGS. 17A and 17B, C
It can be seen that the exchange coupling magnetic field is increased by using the o film at the interface in contact with the antiferromagnetic material forming the magnetization fixed layer 6.

FIG. 18 shows that the first ferromagnetic film 5a made of a Co film has a thickness of 0 ° or 5 °, and the magnetoresistive effect film (samples # 2 and # 1) is formed under two conditions. 4 shows the dependence of the exchange coupling magnetic field and the coercive force on the Ni—Fe film thickness of the second ferromagnetic film 5b after the heat treatment in the magnetic field.
Thus, regardless of the thickness of the Ni—Fe film, the Co film (first
By using the ferromagnetic film 5a) at the interface on the magnetization fixed layer 6, the exchange coupling magnetic field is increased without increasing the coercive force. At this time, the MR ratio hardly changes, and the Co film does not affect the MR ratio.

In this embodiment, a Pt—Mn film is used as the antiferromagnetic film of the magnetization fixed layer 6 as an example.
Similar results were obtained with the -Pt-Mn film. Further, the first ferromagnetic film 5a in contact with the magnetization fixed layer 6 is also made of Co-F
Similar results were obtained using a Co-based alloy film such as e.

In this embodiment, the substrate 1 and the free layer 3
The underlayer 2 made of a Ta film is used to orient the (111) plane of the free layer 3 and to improve the crystallinity between the two. However, even when the underlayer 2 is not used, the effect of the present invention can be obtained. Could be obtained as well.

[Embodiment 6] In this embodiment, the film thickness of the first ferromagnetic film 5a made of a Co film in contact with the magnetization fixed layer 6 is changed from 0 ° to 15 ° by the same film forming method as in the fifth embodiment. The magnetoresistive film thus formed was prepared, and the dependency of each characteristic on the Co film thickness after the heat treatment in the magnetic field under the above conditions was examined.

FIG. 19 shows the exchange coupling magnetic field and the coercive force Co.
FIG. 20 shows the dependency of the magnetoresistance change rate on the Co film thickness. From this, it can be seen that the negotiation coupling magnetic field and the coercive force are saturated when the Co film thickness is 5 ° or more. Further, it can be seen that the magnetoresistance ratio does not depend on the Co film thickness. Therefore, when a Mn-based ordered alloy is used for the magnetization fixed layer 6, it is understood that the thickness of the first ferromagnetic film 5a made of the Co film provided at the interface with the antiferromagnetic film is preferably 5 mm or more. .

[Embodiment 7] In this embodiment, the dependence of the exchange coupling magnetic field on the thickness of the Pt-Mn film serving as the magnetization fixed layer 6 was examined. The sample used in the study was formed by depositing the pinned layer 5 from the magnetization fixed layer 6 side using Co (5 °) by the same film forming method as in the fifth embodiment.
/ Ni-Fe (50 °) / Co (5 °)
The thickness of the Pt—Mn film as the magnetization fixed layer 6 is set to 50 to 500.
The change in the exchange coupling magnetic field and the coercive force was examined by changing the value to Å.

As a result, as shown in FIG. 21, the exchange coupling magnetic field sharply increases when the thickness of the Pt—Mn film reaches 150 °, and the difference from the coercive force becomes maximum. More P
As the thickness of the t-Mn film increases, both the exchange coupling magnetic field and the coercive force gradually increase.

Thus, the magnetization fixed layer 6 in the pinned layer 5
By providing a first ferromagnetic film 5a (Co film) made of a ferromagnetic film having a large exchange coupling energy at the interface with the magnetization fixed layer 6 necessary for obtaining a sufficient exchange coupling magnetic field.
The thickness of the Pt—Mn film is 150
わ か る It turns out that it is good if it is above.

[Embodiment 8] In this embodiment, the thickness of the third ferromagnetic film 5c (Co film) in contact with the nonmagnetic layer 4 in the pinned layer 5 is reduced to 0 ° by the same film forming method as in the fifth embodiment. From 15Å
The magnetoresistive effect film was fabricated with the above changes, and the dependency of the magnetoresistance ratio (MR ratio) after the heat treatment in a magnetic field under the above conditions on the Co film thickness as the third ferromagnetic film 5c was examined.

FIG. 22 shows the relationship between the magnetoresistance ratio (MR ratio) and the C ratio.
o Shows film thickness dependence. From this, it can be seen that the MR ratio of the Co film, which is the third ferromagnetic film 5c, greatly increases at a thickness of 5 °, and is saturated at 5 ° or more. Therefore, the third ferromagnetic film 5 c provided at the interface with the nonmagnetic layer 4 has a configuration in which the Mn-based ordered alloy film is used for the magnetization fixed layer 6.
It can be seen that the thickness of the Co film should be 5 ° or more.

[Embodiment 9] In this embodiment, the film thickness of the nonmagnetic layer 4 made of Cu is set to 18
An optimum film thickness of Cu was studied by forming a magnetoresistive film having a thickness of up to 38 ° and examining the dependence of the sensitivity on the thickness of the Cu film as the nonmagnetic layer 4.

As the Cu film thickness increases, the coupling between the free layer and the fixed layer decreases, but the absolute value of the MR ratio also decreases. As a result, as shown in FIG. 23, the sensitivity of the magnetoresistive effect film shows a dependency on the Cu film thickness such that it takes a maximum value at a Cu film thickness of 28 to 36 °, and the Cu film thickness is 28 to 36 °.
It can be seen that 36 ° is optimal. Here, the sensitivity was measured as a change gradient (% / Oe) of the MR ratio measured after applying a certain magnetic field.

[Embodiment 10] In this embodiment, the pinned layer 5 is a single layer of Co, and the two layers of Ni—Fe / Co are laminated from the side of the magnetization fixed layer 6 by the same film forming method as in Embodiment 5. Membrane, C
Magnetoresistance effect films having three types of three-layered films of o / Ni—Fe / Co were prepared, and respective characteristics after heat treatment in a magnetic field under the above conditions were compared.

Here, the values of the saturation magnetization are different between Co and Ni—Fe, and the dependency on the film thickness cannot be simply compared. Therefore, the change with respect to the total magnetization (Ms * t) of the ferromagnetic layer is compared. Table 2 summarizes the exchange coupling magnetic field, coercive force, and the difference between the structures in which the total magnetization amounts are substantially equal.

[0127]

[Table 2]

From these results, it can be seen that the magnetoresistive effect film composed of a single-layer Co film has the largest values of the exchange coupling magnetic field and the coercive force among the three types of structures. However, looking at the difference between the exchange coupling magnetic field and the coercive force, the Co / Ni-Fe / Co three-layer laminated film shows the largest value, indicating that a stable magnetoresistance effect is obtained. .

[Embodiment 11] In this embodiment, the magnetoresistance effect element shown in FIG. 2 was manufactured using the magnetoresistance effect film described in the first embodiment. This magnetoresistive element moves relative to the medium on which information is magnetically recorded,
The magnitude of the magnetic field received from the magnetic recording medium is detected by the above-described magnetoresistance effect. The method and thickness of the magnetoresistive film were the same as in the first embodiment.
For 22, a Ta / Cu / Ta laminated film was used.

When a magnetic field was applied to the present magnetoresistive element and the reproduction output was measured, the magnetoresistive element having the conventional structure (the magnetoresistive element having the magnetoresistive film shown in FIG. 24) was used.
As compared with the above, a stable reproduction output with respect to magnetic disturbance was obtained. The reproduction output obtained at that time has a track width of 2.5μ.
m, MRhight 0.9 to 1.0 mV / μm at 1.5 μm
Met.

[Embodiment 12] In this embodiment, the magnetoresistance effect element shown in FIG. 3 was manufactured by using the magnetoresistance effect film described in the fourth embodiment. This magnetoresistive element moves relative to the medium on which information is magnetically recorded,
The magnitude of the magnetic field received from the magnetic recording medium is detected by the above-described magnetoresistance effect.

The method and thickness of the magnetoresistive film were the same as in Example 4, and a Ta / Cu / Ta laminated film was used for the electrode. The magnetic domain control layers 25 and 25 have Co-P
t was used.

When a magnetic field was applied to the present magnetoresistance effect element and the reproduction output was measured, the magnetoresistance effect element having the conventional structure (the magnetoresistance effect element having the magnetoresistance effect film shown in FIG. 24) was obtained.
As compared with the above, a stable reproduction output with respect to magnetic disturbance was obtained. The reproduction output obtained at that time has a track width of 2.5μ.
m, 0.9 to 1.0 mV / at MR height 1.5 μm
μm.

In each of the embodiments of the present invention described above, the free layer 3 is constituted by, for example, a two-layer laminated film of a Ni—Fe film and a Co film. Alternatively, the same effect was obtained in a case where the film was composed of three or more laminated films.

In each embodiment of the present invention, the order of lamination of the magnetoresistive film is also such that the free layer 3 / nonmagnetic layer 4 / pinned layer 5 / magnetization fixed layer 6 are formed on the substrate 1 in this order. Is deposited, but by controlling the orientation using an appropriate underlayer, the same effect as in the present embodiment can be obtained even if the layers are deposited in the reverse order.

In producing the above-described magnetoresistive effect film according to the present invention, when a Mn-based ordered alloy film is used for the magnetization fixed layer 6, at least the magnetization fixed layer is required to generate an exchange coupling magnetic field. It is necessary to perform a heat treatment in a magnetic field after the formation of the laminated film of the pin 6 and the pinned layer 5. The heat treatment conditions at that time were applied magnetic field of 300 Oe or more in vacuum,
The conditions are a heat treatment temperature of 230 to 270 ° C. and a holding time of 6 hours.

[0137]

Since the present invention has been described above, it has the following effects.

That is, the magnetoresistance effect element of the present invention suppresses a decrease in the exchange coupling magnetic field and an increase in the coercive force of the second magnetic layer due to thermal disturbance or magnetic disturbance. A magnetoresistive element having a spin-valve magnetoresistive film having a property.

As a result, by applying the magnetoresistive effect element according to the present invention, a magnetic head or a magnetic sensor which is stable against a disturbance magnetic field and has little change in magnetic characteristics over time due to the environment and deterioration in magnetic characteristics due to temperature rise is small. It is possible to provide an excellent magnetic device including the above.

Therefore, the magnetic head of the present invention provided with the magnetoresistive effect element according to the present invention is an excellent magnetic head which is stable against a disturbance magnetic field and has little change in magnetic properties over time due to environment and deterioration of magnetic properties due to temperature rise. Become the head.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a spin-valve magnetoresistive film according to an embodiment of the present invention.

FIG. 2 is a perspective view of a magnetoresistive element including the spin-valve magnetoresistive film of FIG. 1;

FIG. 3 is a perspective view of another magnetoresistive element including the spin-valve magnetoresistive film of FIG. 1;

FIG. 4 shows a first embodiment, in which a Ru—Mn film is used as an antiferromagnetic material film of a magnetization fixed layer, and a C—C film is used as a ferromagnetic material film of a pinned layer (single layer).
FIG. 9 is a characteristic diagram showing the dependence of the exchange coupling magnetic field and the coercive force on the Co film thickness when an o film is used.

FIG. 5 shows a first embodiment, in which a Ru—Mn film is used as an antiferromagnetic film of a fixed magnetization layer, and an N—N film is used as a ferromagnetic film of a pinned layer (single layer).
FIG. 4 is a characteristic diagram showing the dependency of the exchange coupling magnetic field and the coercive force on the Ni—Fe film thickness when an i-Fe film is used.

FIG. 6 shows Example 1, in which a Ru—Mn film is used as an antiferromagnetic film of a fixed magnetization layer, and a Ni—Fe—Nb film is used as a second ferromagnetic film of a pinned layer (three-layered film). FIG. 4 is a characteristic diagram showing the dependency of the exchange coupling magnetic field and the coercive force on the Ni—Fe—Nb film thickness when used.

FIG. 7 is a view showing a second embodiment, in which N is added to a second ferromagnetic film of a pinned layer (three-layer laminated film) composed of a Ni—Fe film.
FIG. 9 is a characteristic diagram showing a change in the total magnetization amount of the entire pinned layer when b, Zr, and Cr are respectively added.

FIG. 8 shows a second embodiment, in which a Ru—Mn film is used as an antiferromagnetic film of a fixed magnetization layer, and a Ni—Fe—Nb film is used as a second ferromagnetic film of a pinned layer (three-layered film). FIG. 4 is a characteristic diagram showing the dependence of the exchange coupling magnetic field and the coercive force on the Nb addition amount when used.

FIG. 9 shows a second embodiment, in which a Ru—Mn film is used as an antiferromagnetic film of a magnetization fixed layer, and a Ni—Fe—Zr film is used as a second ferromagnetic film of a pinned layer (three-layered film). FIG. 7 is a characteristic diagram showing the dependence of the exchange coupling magnetic field and the coercive force on the amount of added Zr when used.

FIG. 10 shows a second embodiment, in which a Ru—Mn film is used as an antiferromagnetic film of a fixed magnetization layer, and a Ni—Fe—Cr film is used as a second ferromagnetic film of a pinned layer (three-layer laminated film). FIG. 6 is a characteristic diagram showing the dependence of the exchange coupling magnetic field and the coercive force on the amount of added Cr when used.

FIG. 11 shows an example 3 in which a Pt—Mn film is used as the antiferromagnetic film of the magnetization fixed layer and a Ni—Fe film is used as the ferromagnetic film of the pinned layer (single layer). FIG. 3 is a characteristic diagram showing the dependency of a coupling magnetic field and a coercive force on a Ni—Fe film thickness.

FIG. 12 shows Example 3, and shows an exchange coupling magnetic field when a Pt—Mn film is used as an antiferromagnetic film of a fixed magnetization layer and a Co film is used as a ferromagnetic film of a pinned layer (single layer). And Coercivity Co
FIG. 4 is a characteristic diagram showing film thickness dependence.

FIG. 13 shows a third embodiment, in which a Pt—Mn film is used as an antiferromagnetic material film of a magnetization fixed layer, and Co / is used as a pinned layer (three-layer laminated film).
FIG. 4 is a characteristic diagram showing the dependency of the exchange coupling magnetic field and the coercive force on the Ni—Fe film thickness when a Ni—Fe / Co laminated film is used.

FIG. 14 shows Example 4, in which a Pt—Mn film is used as an antiferromagnetic film of a magnetization fixed layer, and a Ni—Fe—Nb film is used as a second ferromagnetic film of a pinned layer (three-layered film). FIG. 4 is a characteristic diagram showing the dependence of the exchange coupling magnetic field and the coercive force on the Nb addition amount when used.

FIG. 15 shows Example 4, in which a Pt—Mn film was used as the antiferromagnetic film of the magnetization fixed layer, and a Ni—Fe—Zr film was used as the second ferromagnetic film of the pinned layer (three-layer laminated film). FIG. 7 is a characteristic diagram showing the dependence of the exchange coupling magnetic field and the coercive force on the amount of added Zr when used.

FIG. 16 shows a fourth embodiment, in which a Pu—Mn film is used as an antiferromagnetic film of a magnetization fixed layer, and a Ni—Fe—Cr film is used as a second ferromagnetic film of a pinned layer (three-layered film). FIG. 6 is a characteristic diagram showing the dependence of the exchange coupling magnetic field and the coercive force on the amount of added Cr when used.

17A and 17B show Example 5 in which (a) is a magnetization curve in the case where there is no Co film on the pinned layer in contact with the fixed magnetization layer, and (b) is a magnetization curve in the pinned layer in contact with the fixed magnetization layer. 7 shows a magnetization curve when a Co film exists.

FIG. 18 shows a fifth embodiment, in which a Pt—Mn film is used as the antiferromagnetic film of the fixed magnetization layer, and Ni is used as the pinned layer from the magnetization fixed layer side.
-Coupling magnetic field and coercive force Ni of two samples using a laminated film of -Fe / Co and a laminated film of Co / Ni-Fe / Co
FIG. 3 is a characteristic diagram showing dependency on Fe film thickness.

FIG. 19 shows a sixth embodiment, in which a Pt—Mn film is used as the antiferromagnetic film of the magnetization fixed layer, and a pin layer is made of Co from the magnetization fixed layer side.
/ Ni—Fe / Co, which is the first ferromagnetic film on the magnetization fixed layer side of the exchange coupling magnetic field and the coercive force,
6 is a characteristic diagram showing the film thickness dependence.

FIG. 20 shows Example 6, in which a Pt—Mn film is used as the antiferromagnetic film of the magnetization fixed layer, and a pin layer is made of Co from the magnetization fixed layer side.
FIG. 7 is a characteristic diagram showing the dependency of the magnetoresistance ratio (MR ratio) on the Co film thickness of the first ferromagnetic film on the magnetization fixed layer side when a / Ni—Fe / Co laminated film is used.

FIG. 21 shows a seventh embodiment, in which a Pt—Mn film is used as the antiferromagnetic film of the magnetization fixed layer, and a pin layer is made of Co from the magnetization fixed layer side.
FIG. 4 is a characteristic diagram showing the dependency of the magnetoresistance ratio (MR ratio) on the thickness of a Pt—Mn film serving as a magnetization fixed layer in the case of a stacked film of / Ni—Fe.

FIG. 22 shows Example 8, in which a Pt—Mn film is used as the antiferromagnetic film of the magnetization fixed layer, and a pin layer is made of Co from the magnetization fixed layer side.
/ Ni—Fe / Co, which is the third ferromagnetic film on the non-magnetic layer side of the magnetoresistance ratio (MR ratio) in the case of a laminated film of C / Ni—Fe / Co
6 is a characteristic diagram showing the film thickness dependence.

FIG. 23 shows a ninth embodiment, in which a Pt—Mn film is used as the antiferromagnetic film of the magnetization fixed layer, and a pin layer is made of Co from the magnetization fixed layer side.
FIG. 10 is a characteristic diagram showing the dependency of the sensitivity of the magnetoresistive film in the case of a laminated film of / Ni—Fe / Co on the thickness of a Cu film as a nonmagnetic layer.

FIG. 24 is a sectional view of a conventional spin-valve magnetoresistive film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate (glass) 2 Underlayer (underlayer) 3 Free layer (1st magnetic layer) 4 Nonmagnetic layer 5 Pinned layer (2nd magnetic layer) 5a, 5b, 5c Ferromagnetic film 6 Fixed magnetization layer 7 Protective film Reference Signs List 21 spin valve type magnetoresistive film 22 electrode 23, 24 shield layer 25 magnetic domain control layer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Haruhiko 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (72) Inventor Keiya Nakabayashi 22-22, Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Sharp Corporation

Claims (16)

[Claims] 1. A magnetoresistive element provided with a spin-valve magnetoresistive film having a four-layer structure of a first magnetic layer / nonmagnetic layer / second magnetic layer / magnetization fixed layer as a basic structure. The layer is composed of an antiferromagnetic film, while the second magnetic layer is a multilayer film composed of two or more ferromagnetic films, of which a layer in contact with the magnetization fixed layer is a magnetization fixed layer. And a layer other than the layer on the side in contact with the magnetization fixed layer includes a layer made of a ferromagnetic film having a small saturation magnetization. Magnetoresistive element. 2. A layer other than a layer in contact with the fixed magnetization layer in the multilayer film constituting the second magnetic layer, a layer made of a ferromagnetic film having a small saturation magnetization and a ferromagnetic film different from the ferromagnetic film. 2. The magnetoresistive element according to claim 1, wherein the magnetoresistive element is a multilayer film including a body film. 3. A multi-layered film constituting the second magnetic layer, wherein a layer on the side in contact with the non-magnetic layer is made of a ferromagnetic film which does not easily diffuse with the non-magnetic layer. Or 2
3. The magnetoresistive effect element according to item 1. 4. The multi-layered film forming the second magnetic layer, wherein a layer made of a ferromagnetic film having a small saturation magnetization has a larger thickness than other layers in the multi-layered film. 3. The magnetoresistive element according to any one of 3. 5. The method according to claim 1, wherein the magnetization fixed layer is made of a Mn-based antiferromagnetic ordered alloy film, and is heat-treated during magnetization after laminating at least the second magnetic layer and the magnetization fixed layer. The magnetoresistive element according to any one of claims 1 to 4, wherein 6. The Mn-based antiferromagnetic ordered alloy film is made of PtM.
6. The magnetoresistive element according to claim 5, comprising an n alloy film or a PdPtMn alloy film. 7. The PtMn alloy film or PdPtMn
7. The magnetoresistive element according to claim 6, wherein the layer made of the alloy film has a thickness of 150 [deg.] Or more. 8. The method according to claim 5, wherein a layer of the second magnetic layer in contact with the magnetization fixed layer is made of a Co film or a Co-based alloy film such as a CoFe alloy film. The magnetoresistive effect element as described in the above. 9. The method according to claim 8, wherein the thickness of the layer made of the Co film or the Co-based alloy film is 5 ° or more.
3. The magnetoresistive effect element according to item 1. 10. The magnetic layer according to claim 5, wherein the layer made of a ferromagnetic film having a small saturation magnetization in the multilayer film forming the second magnetic layer is made of a NiFe alloy film. Resistance effect element. 11. The multi-layered film forming the second magnetic layer, wherein the layer made of a ferromagnetic film having a small saturation magnetization includes a multi-layered film of a layer made of a NiFe alloy film and a layer made of a Co film. The magnetoresistive element according to any one of claims 5 to 9. 12. The method according to claim 3, wherein the layer made of a ferromagnetic film that is hardly interdiffused with the nonmagnetic layer is made of a Co film or a Co-based alloy film such as a CoFe alloy film. 12. The magnetoresistive element according to any one of items 11 to 11. 13. The magnetoresistive element according to claim 12, wherein the layer made of the Co film or the Co-based alloy film has a thickness of 5 ° or more. 14. The magnetoresistive element according to claim 4, wherein said nonmagnetic layer is made of a Cu film and has a thickness of 28 ° to 36 °. 15. The spin valve type magnetoresistive film according to claim 1, wherein said spin valve type magnetoresistive film is provided on a substrate via an underlayer for controlling the orientation and improving the crystallinity.
The magnetoresistance effect element according to any one of the above. 16. A magnetoresistive element according to claim 1, an energizing means for passing a current through said magnetoresistive element, and a magnetic field corresponding to magnetic information recorded on a magnetic recording medium. Detecting means for detecting the electric resistance of the magnetoresistive element, which changes in accordance with the size of the magnetic head.