JP3527786B2 - Multilayer magnetoresistive film and magnetic head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer magnetoresistive effect film having a high magnetoresistive effect, a magnetoresistive effect element using the same, a magnetic head and a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art As the magnetic recording density has increased, a material having a high magnetoresistive effect in a low magnetic field region has been required as a magnetoresistive effect material used for a reproducing magnetic head. 1991, Physical Review B (Physical Revi)
ew B), Vol. 43, No. 1, pp. 1297-1300, "Giant magnetoresistance effect in soft magnetic multilayer film (Giant
Magnetoresistance in Soft Ferromagnetic Multilayer
s) ”, a relatively high magnetoresistance change rate has been reported in a magnetic film having a multilayer structure.

[0003]

The above-mentioned multilayer film has a structure in which two magnetic layers are separated by a nonmagnetic layer, and an antiferromagnetic layer is in contact with one magnetic layer. For the antiferromagnetic layer, an Fe-Mn-based alloy is generally used. Fe
The -Mn-based alloy exhibits antiferromagnetism at room temperature when it has a face-centered cubic structure. Japanese Journal of Applied Physics
ysics), Vol. 33, No. 1A, pp. 133-137, "Fe-Mn / N with Various Buffer Layer Materials".
Magnetoresistance Effect and Crystal Orientation in i-Fe / Cu / Ni-Fe Sandwich
eferred Orientation in Fe-Mn / Ni-Fe / Cu / Ni-Fe Sandwi
ches with various buffer layer materials), in order to make the Fe—Mn alloy layer have a face-centered cubic structure, the multilayer film has IVa and Va of the periodic table.
It is formed on the buffer layer made of a group element. However, when a buffer layer is included in the above-mentioned multilayer film, a sputtering apparatus having at least four types of targets is required. In order to increase the rate of change in magnetic resistance, Ni-F
In order to form the Co layer between the e layer and the Cu layer, a sputtering device having five types of targets is required.

[0004]

The inventors of the present invention have conducted extensive studies on the magnetoresistive effect element using the above-mentioned multilayer film, and as a result, oxidation of a 3d transition metal element between the multilayer film and the substrate has occurred. It was found that the Fe-Mn-based alloy layer in the multilayer film can have a face-centered cubic structure by forming a buffer layer made of a material, and completed the present invention.

That is, 3d of SiO ₂ , Al ₂ O _3, etc.
Even if a multilayer film in which magnetic layers and nonmagnetic layers are alternately laminated is formed on an oxide layer other than a transition metal element, the Fe-Mn-based alloy layer in the multilayer film is sufficiently face-centered cubic. The structure does not have a structure, and the exchange bias magnetic field applied from the Fe—Mn alloy layer to the magnetic layer is low. On the other hand, when the multilayer film is formed on the layer made of the oxide of the 3d transition metal element, the Fe-Mn alloy layer in the multilayer film has a sufficiently face-centered cubic structure, and the Fe-Mn alloy is The exchange bias field applied from the layer to the magnetic layer is high. The value of the exchange bias magnetic field is almost the same as the value of the exchange bias magnetic field in the multilayer film formed on the buffer layer made of the IVa and Va group elements.

The multilayer magnetoresistive effect film is suitable for a magnetoresistive effect element, a magnetic field sensor, a magnetic head and the like. Further, by using the above magnetic head, a high performance magnetic recording / reproducing apparatus can be obtained.

[0007]

As described above, the exchange bias magnetic field applied from the Fe--Mn alloy layer to the magnetic layer is formed by forming the buffer layer composed of the oxide of the 3d transition metal element between the multilayer film and the substrate. Can be higher. Since the oxide of the 3d transition metal element functions as a buffer layer even if it is taken out into the air after being formed, the amount of sputtering / cathode sputtering is less than that in the case of using the conventional buffer layer made of the IVa and Va group elements. A device can be used. Furthermore, the multilayer magnetoresistive effect film is suitable for a magnetoresistive effect element, a magnetic field sensor, a magnetic head, and the like. Further, by using the magnetic head, a high performance magnetic recording / reproducing device can be obtained.

[0008]

【Example】

<Example 1> FIG. 1 shows a multilayer film structure of an example of the present invention. As the substrate 11, a Si (100) single crystal substrate was used.
First, the Ni—O based buffer layer 12 having various thicknesses was formed on the substrate 11 by using an ion beam sputtering apparatus. Although NiO was used as the sputtering target, it is considered that the composition of the buffer layer formed by sputtering deviates from the stoichiometric composition. The sputtering conditions are an Ar pressure of 0.02 Pa, an ion gun acceleration voltage of 900 V, and an ion current of 120 mA.

The 3-inch Si substrate on which the Ni--O buffer layer was formed was once taken out from the ion beam sputtering apparatus, cut into a size of 7 mm × 7 mm, and then returned to the inside of the apparatus again. Further, on the Ni—O-based buffer layer 12 formed on the substrate 11, a Ni—F having a thickness of 10.0 nm is formed.
e-Co magnetic layer 13, Cu non-magnetic layer 1 having a thickness of 3.0 nm
4, a Ni—Fe—Co magnetic layer 15 having a thickness of 5.0 nm, a Fe—Mn alloy antiferromagnetic layer 16 having a thickness of 10.0 nm, and a Ta protective layer 17 having a thickness of 5.0 nm were laminated. The sputtering conditions are an Ar pressure of 0.02 Pa, an ion gun acceleration voltage of 300 V, and an ion current of 30 mA. Ni-Fe-
The sputtering target for forming the Co magnetic layer includes N
An alloy target having a composition of i-16 at% Fe-18 at% Co was used. In addition, the sputtering target for forming the Fe-Mn alloy antiferromagnetic layer is Fe-50 at.
An alloy target having a composition of% Mn was used. At the same time, the multilayer film was also laminated on the Si substrate on which the Ni—O based buffer layer was not formed. An oxide layer mainly composed of SiO ₂ exists on the surface of the Si substrate on which the Ni—O-based buffer layer is not formed.

FIG. 2 shows the relationship between the thickness of the Ni—O layer of the buffer layer and the magnetization curve of the multilayer film. The change in the magnetization near the zero magnetic field shown in the figure is due to the magnetization reversal of the magnetic layer 13 not in contact with the antiferromagnetic layer 16. Further, the change in the magnetization seen in the positive magnetic field region is caused by the magnetization reversal of the magnetic layer 15 in contact with the antiferromagnetic layer 16. That is, the magnetic layer 15
Is applied with the exchange bias magnetic field from the antiferromagnetic layer 16, and the magnetization curve shifts accordingly. The shifted amount is called an exchange bias magnetic field.

As shown in the figure, the exchange bias magnetic field increases with the thickness of the Ni-O layer. Therefore, the magnetic layer 1
3 and the height of the magnetic field for reversing the magnetization of the magnetic layer 15 are significantly different. Between the magnetic field for reversing the magnetization of the magnetic layer 13 and the magnetic field for reversing the magnetization of the magnetic layer 15, the magnetization directions of the two magnetic layers are antiparallel.

When the multilayer film is applied to a magnetoresistive effect element, the magnetoresistive effect element is used in the vicinity of zero magnetic field. When used in this region, the hysteresis of the change in magnetization is small. However, a high magnetic field may be applied to the multilayer film for some reason. At this time, when the applied magnetic field is high and the magnetization of the magnetic layer 15 in contact with the antiferromagnetic layer 16 is reversed,
As a result, the hysteresis of the change in magnetization becomes large. Therefore, the exchange bias magnetic field applied to the magnetic layer 15 is preferably high.

FIG. 3 shows the relationship between the thickness of the Ni—O layer of the buffer layer and the exchange bias magnetic field applied to the magnetic layer 15. As shown, when the thickness of the Ni—O layer is 0 nm, that is, when the multilayer film is formed on SiO ₂ on the Si substrate, the exchange bias magnetic field is about 5 kA / m. On the other hand, when the buffer layer 12 made of Ni—O is provided, N
The exchange bias magnetic field increases with the thickness of the i-O layer. When the thickness of the Ni—O layer becomes 10 nm, the height of the exchange bias magnetic field is almost saturated. In a multilayer film using a buffer layer such as Ta or Hf, the value of the exchange bias magnetic field is about 1
It is 2 kA / m. Therefore, the multilayer film of this embodiment using the Ni—O buffer layer exhibits almost the same characteristics as the multilayer film using the buffer layer of Ta, Hf, or the like. Further, as shown in the figure, the Ni—O layer functions as a buffer layer even if it is as thin as 2.5 nm. Therefore, the thickness of the buffer layer is preferably 2.5 nm or more.

FIG. 4 shows the relationship between the thickness of the Ni—O layer of the buffer layer and the coercive force of the magnetic layer 13. In the region where the thickness of the Ni-O layer is 12.5 nm or less, the coercive force of the magnetic layer 13 is almost constant. On the other hand, the thickness of the Ni-O layer is 12.
When the thickness is more than 5 nm, the coercive force of the magnetic layer 13 rapidly increases. Therefore, from the viewpoint of coercive force, the thickness of the buffer layer is preferably 12.5 nm or less. Also,
From the above results, in order to increase the exchange bias magnetic field applied to the magnetic layer 15 and reduce the coercive force of the magnetic layer 13, the thickness of the buffer layer needs to be 2.5 to 12.5 nm. .

FIG. 5 shows the relationship between the thickness of the Ni—O layer of the buffer layer and the magnetoresistance change rate. As shown in the figure, the rate of change in magnetic resistance is about 3% and is almost constant.

FIG. 6 shows the result of an examination of the cause of the increase in the exchange bias magnetic field applied to the magnetic layer 15 due to the Ni—O buffer layer. As shown in the figure, Ni in the multilayer film
The X-ray diffraction intensity of the (111) plane of the crystals of the —Fe—Co layer and the Cu layer increases with the Ni—O layer thickness. As described in the Japanese Journal of Applied Physics, Vol. 33, No. 1A, pp. 133-137, when the X-ray diffraction intensity of the (111) plane of the crystals of the Ni—Fe and Cu layers becomes high, The Fe-Mn alloy has a face-centered cubic structure and exhibits antiferromagnetism at room temperature. For this reason,
In a multilayer film having a high (111) plane X-ray diffraction intensity, a high exchange bias magnetic field is applied to the magnetic layer in contact with the antiferromagnetic layer. Therefore, by providing the Ni—O buffer layer, the (111) plane orientation of the multilayer film becomes strong, and therefore,
It is considered that the exchange bias magnetic field applied to the magnetic layer 15 was increased.

In the present embodiment, the case where Cu is used as the nonmagnetic layer 14 has been described, but the same result can be obtained by using Au or Ag. Also, C
An alloy containing u, Ag, and Au as a main component can be used as the nonmagnetic layer 14.

Further, in the present embodiment, the magnetic layers 13 and 15 are made of Ni--Fe--Co alloy, but
Ni-Fe based alloys can also be used.

In this embodiment, the Fe-Mn alloy is used as the antiferromagnetic layer 16, but the same result can be obtained by using other Mn alloy antiferromagnetic material. Other antiferromagnetic materials include Mn-Ir, Mn-Ni, Mn-Pt-Co,
Mn-Co, Mn-Pt, Mn-Pd, etc. are preferable.

As the substrate 11, a substrate other than Si single crystal can be used.

<Embodiment 2> In Embodiment 1, the case where Ni--O is used as the buffer layer has been described. In this embodiment, a case where a buffer layer of an oxide of another 3d transition metal element is used will be described. The thickness of the buffer layer is 10 nm
The structure of the other multilayer films was the same as in Example 1. The results are shown in Table 1. As shown in the table, in comparison with the case where the oxide buffer layer other than the 3d transition metal element such as SiO ₂ and Al ₂ O ₃ is used, when the buffer layer made of the oxide of the 3d transition metal element is used, the magnetic layer The exchange bias field applied to 15 is high.

[0022]

[Table 1]

Further, the effect of the thickness of the buffer layer of the oxide of the 3d transition metal element on the magnetoresistance change rate of the multilayer film was examined, and as in the case of using Ni--O, it was 2.5-12. .5
A buffer layer thickness of nm has been found to be preferred.

Example 3 The same experiment as in Example 1 was conducted on a multilayer film in which Co was used as a part of the magnetic layer. Figure 7
Shows the structure of the multilayer film. The multilayer film was formed by the same method as in Example 1. A Si (100) single crystal substrate was used as the substrate 21. The buffer layer 22 was made of Ni—O based materials having various thicknesses. Further, on the Ni—O-based buffer layer 22 formed on the substrate 21, a Ni—Fe layer having a thickness of 9.0 nm is formed.
-Co magnetic layer 23, Co magnetic layer 24 having a thickness of 1.0 nm,
Cu non-magnetic layer 25 with a thickness of 3.0 nm, C with a thickness of 2.0 nm
A magnetic layer 26, a Ni-Fe-Co magnetic layer 27 having a thickness of 3.0 nm, a Fe-Mn alloy antiferromagnetic layer 28 having a thickness of 10.0 nm, and a Cu protective layer 29 having a thickness of 5.0 nm are laminated. .

FIG. 8 shows the relationship between the thickness of the Ni—O layer of the buffer layer and the magnetization curve of the multilayer film. As shown in the figure, the formation of the buffer layer increases the exchange bias magnetic field applied to the magnetic layers (magnetic layer 26 and magnetic layer 27) in contact with the antiferromagnetic layer 28.

FIG. 9 shows the relationship between the thickness of the Ni—O layer of the buffer layer and the exchange bias magnetic field applied to the magnetic layer in contact with the antiferromagnetic layer. As shown in the figure, when the thickness of the Ni—O layer is 0 nm, that is, when the multilayer film is formed on SiO ₂ on the Si substrate, the exchange bias magnetic field is about 4 kA / m. On the other hand, when the buffer layer 22 made of Ni—O is provided, the exchange bias magnetic field becomes higher with the thickness of the Ni—O layer. When the thickness of the Ni-O layer becomes 5 nm,
The height of the exchange bias magnetic field is almost saturated. Further, as shown in the drawing, the Ni—O layer functions as a buffer layer even if it is as thin as 2.5 nm. Therefore, the thickness of the buffer layer is preferably 2.5 nm or more.

FIG. 10 shows the relationship between the thickness of the Ni—O layer of the buffer layer and the coercive force of the magnetic layers (magnetic layer 23 and magnetic layer 24) not in contact with the antiferromagnetic layer 28. In the region where the thickness of the Ni—O layer is 12.5 nm or less, the coercive force of the magnetic layer is almost constant. On the other hand, the thickness of the Ni-O layer is 1
When it becomes thicker than 2.5 nm, the coercive force of the magnetic layer rapidly increases. Therefore, from the viewpoint of coercive force, the thickness of the buffer layer is preferably 12.5 nm or less. From the above results, in order to increase the exchange bias magnetic field applied to the magnetic layers 26 and 27 and decrease the coercive force of the magnetic layers 23 and 24, the thickness of the buffer layer should be 2.5 to 12.
It must be 5 nm.

FIG. 11 shows the relationship between the thickness of the Ni—O layer of the buffer layer and the magnetoresistance change rate. As shown in the figure, the rate of change in magnetic resistance is about 4%. This value is higher than in Example 1. This is because Co is used for a part of the magnetic layer. Also,
As shown in the figure, the magnetoresistance change rate decreases due to the formation of the Ni—O layer, but the cause is unknown.

Further, as shown in FIG. 12, depending on the thickness of the Ni—O buffer layer, the Ni—Fe—Co layer, the Co layer in the multilayer film,
And the X-ray diffraction intensity of the (111) plane of the crystal of the Cu layer increases. It is considered that the change in the structure observed with the increase in the X-ray diffraction intensity of the (111) plane is caused by making the Fe-Mn alloy a face-centered cubic structure and increasing the exchange bias magnetic field applied to the magnetic layer.

In the present embodiment, the case where Cu is used for the nonmagnetic layer 25 has been described, but the same result can be obtained by using Au or Ag. Also, C
An alloy containing u, Ag, and Au as a main component can be used as the nonmagnetic layer 25.

Further, in this embodiment, the magnetic layers 23 and 27 are made of Ni--Fe--Co alloy, but
Ni-Fe based alloys can also be used.

In this embodiment, the Fe-Mn alloy is used as the antiferromagnetic layer 28, but the same result can be obtained by using other Mn alloy antiferromagnetic material. Other antiferromagnetic materials include Mn-Ir, Mn-Ni, Mn-Pt-Co,
Mn-Co, Mn-Pt, Mn-Pd, etc. are preferable.

As the substrate 21, a substrate other than Si single crystal can be used.

<Embodiment 4> The buffer layer 22 shown in FIG.
As Ni-O (10.0 nm) / NM (10.0 nm)
A material having a laminated structure of <NM is a non-magnetic metal> was used. A multilayer film similar to that in Example 3 was formed on the buffer layer. Table 2 shows the relationship between the buffer layer material and the magnetoresistance change rate.

[0035]

[Table 2]

As shown in Table 2, IV of the periodic table as NM
When the a and Va group elements are used, the Ni—O described in Example 3 is used.
A magnetic resistance change rate higher than the magnetic resistance change rate of 3.7% in the case of only is obtained.

In this embodiment, only Ni-O has been described, but similar results can be obtained by using an oxide of another 3d transition metal element.

Example 5 A magnetoresistive effect element using the multilayer film of the present invention was formed. In this embodiment, as the buffer layer 12 in FIG. 1, Ni-O having a thickness of 10 nm is used. The structure of the magnetoresistive element is shown in FIG. 13 in which the multilayer film described in the first embodiment is formed on the buffer layer 12. The magnetoresistive effect element has a structure in which a multilayer magnetoresistive effect film 51 and an electrode 52 are sandwiched by shield layers 53 and 54. When a magnetic field was applied to the magnetoresistive effect element and a change in electric resistivity was measured, it was found that the magnetoresistive effect element using the multilayer magnetoresistive effect film of the present invention has an applied magnetic field of about 2.4 kA / m (30 Oe). Three
The magnetic resistance change rate was about%. Further, the reproduction output of the magnetoresistive effect element of the present invention was 2.5 times that of the magnetoresistive effect element using the Ni-Fe single layer film.

In this embodiment, N is used as the buffer layer material.
Although i-O is used, all the buffer layer materials of the present invention described in Example 2 can be used as a multilayer buffer layer for a magnetoresistive effect element. Further, a multilayer film using Co can be used as a part of the magnetic layer described in the third and fourth embodiments.

Example 6 A magnetic head was produced using the magnetoresistive effect element described in Example 4. The structure of the magnetic head is shown below. FIG. 14 is a perspective view when a part of the recording / reproducing separated type head is cut. The portion of the multilayer magnetoresistive effect film 61 sandwiched by the shield layers 62 and 63 functions as a reproducing head, and the portions of the lower magnetic pole 65 and the upper magnetic pole 66 that sandwich the coil 64 function as a recording head. Also, the electrode 68
As the material, a material having a multilayer structure of Cr / Cu / Cr was used.

The manufacturing method of this head will be described below. Al
_A sintered body containing ₂ O ₃ .TiC as a main component was used as the slider substrate 67. A Ni-Fe alloy formed by a sputtering method was used for the shield layer and the recording magnetic pole. The thickness of each magnetic film was as follows. The upper and lower shield layers 62 and 63 were 1.0 μm, the lower magnetic pole 65 and the upper part 66 were 3.0 μm, and the gap material between the layers was Al ₂ O ₃ formed by sputtering. The film thickness of the gap layer was 0.2 μm between the shield layer and the magnetoresistive effect element and 0.4 μm between the recording magnetic poles. Further, the distance between the reproducing head and the recording head was set to about 4 μm, and this gap was also formed of Al ₂ O ₃ . Cu having a film thickness of 3 μm was used for the coil 64.

When recording / reproducing was performed with the magnetic head having this structure, a reproducing output 2.3 times higher than that of the magnetic head using the Ni--Fe single layer film was obtained. It is considered that this is because the magnetic head of the present invention uses a multilayer film having a high magnetoresistive effect.

Further, the magnetoresistive effect element of the present invention can be used in a magnetic field detector other than the magnetic head.

<Embodiment 7> Using the magnetic head of the present invention described in Embodiment 6, a magnetic disk device was manufactured. The configuration of the device is shown in FIG. For the magnetic recording medium 71, a material made of a Co—Ni—Pt—Ta alloy having a residual magnetic flux density of 0.75T was used. The track width of the magnetic head 73 is 3 μm
And The magnetoresistive effect element in the magnetic head 73 is
Since the reproduction output is high, a high-performance magnetic disk device which does not burden the signal processing was obtained.

[0045]

When the buffer layer of the oxide of the 3d transition metal element is formed between the multilayer film and the substrate, the exchange bias magnetic field from the antiferromagnetic layer applied to the magnetic layer in the multilayer film increases. Therefore, it is possible to obtain a multi-layered film having excellent magnetic characteristics with less hysteresis in the magnetization process. Further, since excellent characteristics can be obtained even after exposure to the atmosphere once after the formation of the buffer layer, a multilayer film can be formed even by using a sputtering apparatus with few sputtering cathodes.
Further, the multilayer film of the present invention exhibits a magnetoresistive effect at a low applied magnetic field. Furthermore, the multilayer magnetoresistive effect film is suitable for a magnetoresistive effect element, a magnetic field sensor, a magnetic head, and the like. Also,
A high-performance magnetic recording / reproducing apparatus can be obtained by using the magnetic head.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a multilayer magnetoresistive effect film of the present invention.

FIG. 2 is a graph showing the relationship between the Ni—O buffer layer thickness and the magnetization curve of a multilayer film.

FIG. 3 is a graph showing the relationship between the Ni—O buffer layer thickness and the exchange bias magnetic field applied to the magnetic layer in contact with the antiferromagnetic layer.

FIG. 4 is a graph showing the relationship between the Ni—O buffer layer thickness and the coercive force of the magnetic layer that is not in contact with the antiferromagnetic layer.

FIG. 5 is a graph showing the relationship between the Ni—O buffer layer thickness and the magnetoresistance change rate of the multilayer film.

FIG. 6 is a graph showing the relationship between the Ni—O buffer layer thickness and the X-ray diffraction intensity of the (111) plane of the multilayer film.

FIG. 7 is a sectional view showing the structure of the multilayer magnetoresistive effect film of the present invention.

FIG. 8 is a graph showing the relationship between the Ni—O buffer layer thickness and the magnetization curve of a multilayer film.

FIG. 9 is a graph showing the relationship between the Ni—O buffer layer thickness and the exchange bias magnetic field applied to the magnetic layer in contact with the antiferromagnetic layer.

FIG. 10 is a graph showing the relationship between the Ni—O buffer layer thickness and the coercive force of the magnetic layer that is not in contact with the antiferromagnetic layer.

FIG. 11 is a graph showing the relationship between the Ni—O buffer layer thickness and the magnetoresistance change rate of the multilayer film.

FIG. 12: Ni-O buffer layer thickness and multilayer film (111)
The graph which shows the relationship with the X-ray diffraction intensity of a surface.

FIG. 13 is a perspective view showing the structure of a magnetoresistive effect element using the multilayer magnetoresistive effect film of the present invention.

FIG. 14 is a perspective view showing the structure of the magnetic head of the present invention.

FIG. 15 is an explanatory diagram of a magnetic recording / reproducing apparatus of the present invention.

[Explanation of symbols]

11 ... Substrate, 12 ... Buffer layer, 13, 15 ... Magnetic layer,
14 ... Nonmagnetic layer, 16 ... Antiferromagnetic layer, 17 ... Protective layer.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-6329 (JP, A) JP-A-6-325934 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 5/31-5/39 H01F 10/30

Claims (8)

(57) [Claims] 1. A multilayer film in which two magnetic layers are separated by a non-magnetic layer and an antiferromagnetic layer is in contact with one magnetic layer is formed on a layer made of an oxide of a 3d transition metal element. A multi-layered magnetoresistive effect film characterized by being formed. 2. The multilayer magnetoresistive effect film according to claim 1, wherein the oxide of the 3d transition metal element is a material selected from the group consisting of Ni—O, Fe—O and Co—O. 3. The N according to claim 1 or 2,
A multilayer magnetoresistive effect film in which a layer of a material selected from the group of i-O, Fe-O, and Co-O has a thickness of 2.5 to 12.5 nm. 4. The above 3d according to claim 1, 2 or 3.
Between the oxide layer of the transition metal element and the substrate, IV of the periodic table
A multi-layered magnetoresistive effect film in which a metal layer composed of a and Va group elements is formed. 5. A magnetoresistive effect element using at least a part of the multilayer magnetoresistive effect film according to claim 1, 2, 3 or 4. 6. A magnetic head using the magnetoresistive effect element according to claim 5 in at least a part thereof. 7. A composite magnetic head in which the magnetoresistive effect element according to claim 5 and an inductive magnetic head are combined. 8. A magnetic recording / reproducing apparatus using the magnetic head according to claim 6.