JPH05175572A - Magnetoresistance effect element, and magnetic head and recording/reproducing device using same - Google Patents

Abstract

PURPOSE:To eliminate Barkhausen noise by applying a bias magnetic field in an easy-to-magnetize direction of magnetic layer by using a magnetic resistance effect film of multilayer construction in which magnetic layer and nonmagnetic layer are piled up. CONSTITUTION:A magnetro-resistance effect element 10 has a multilayer film 7 in which magnetic layer and nonmagnetic layer are piled up and is applied with a bias magnetic field in a easy-to-magnetize-direction of the magnetic layer constituting the multilayer film 7. This system can be applied for the multilayer film which contains at least one magnetic layer whose coersive force or anisotropic magnetic field differs from that of other magnetic layers, the multi-layer film where the magnetization of respective magnetic layers is in an anti-parallel direction due to the mutual exchange function among the magnetic layers when there is no external magnetic field, or the element 10 of multilayer film construction in which at least one of magnetic layers has an easy-to-magnetize direction different from that of other magnetic layers. A permanent magnet layer 8 or anti-ferromagnetic layer, etc., is used to apply the bias magnetic field. Thus, Barihousen noise can effectively be eliminated, resulting in enhancing high recording/reproducing performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for suppressing Barkhausen noise particularly in a magnetoresistive effect element having a high magnetoresistive effect, which is composed of a multilayer film formed by laminating a magnetic layer and a nonmagnetic layer. The present invention relates to a magnetoresistive effect element having a structure, a magnetic head using the same, and a magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art As the magnetic recording density has increased, a material exhibiting a high magnetoresistive effect has been required as a magnetoresistive effect material used for a reproducing magnetic head. At present, permalloy, which is widely used, has a magnetoresistance change rate of about 3%, and a new material is required to have a magnetoresistance change rate higher than this. Recently, a physical review letter (Physical) by Baibich et al.
Review Letters), Volume 61, Volume 21
No. 2472-2475, "(001) Fe"
/ (001) Cr magnetic superlattice giant magnetoresistance effect "(G
iant Magnitudes of of
(001) Fe / (001) Cr Magnetic
In a magnetic film (Fe / Cr multilayer film) having a multilayer structure like Superlattices, a magnetoresistance change rate (at 4.2 K) of about 50% is observed. Also, Shinjo et al., Journal of the Physical Society of Japan (Journ
al of ThePhysical Society
of Japan), Volume 59, No. 9, 3061
~ 3064 "Magnetic resistance effect of large ferrimagnetic multi-layer film induced by magnetic field (LargeMagneto)
resistance of Field-Induc
ed Giant Ferrimagnetic Mu
In a magnetic film (Co / Cu / Ni-Fe / Co multilayer film) having a multilayer structure, as shown in FIG.
A magnetoresistance change rate of 9.9% is observed.

[0003]

Even when the magnetoresistive effect film having the above-mentioned multilayer film structure is used, in the case of the magnetoresistive effect element in which the Ni--Fe alloy such as permalloy which is the conventional material is used as the magnetoresistive effect film. Similarly, there was a problem that Barkhausen noise was generated.

An object of the present invention is to solve the above-mentioned problems in the prior art. In a magnetoresistive effect element having a multilayer film structure, a magnetoresistive effect element having a structure capable of effectively suppressing the generation of Barkhausen noise. Another object of the present invention is to provide a high-performance magnetic head using the same and a high-performance magnetic recording / reproducing apparatus having a high recording density.

[0005]

In order to achieve the above object, the inventors of the present invention have proposed a magnetoresistive device using a magnetic film having a multi-layer structure in which magnetic layers having various materials and film thicknesses and non-magnetic layers are laminated. As a result of intensive research on the effect element, by applying a bias magnetic field in the direction of easy magnetization of the magnetic layer,
They have found that Barkhausen noise can be effectively suppressed, and have completed the present invention. That is,
In a magnetoresistive effect element using a magnetoresistive effect film having a multilayer structure in which a magnetic layer and a nonmagnetic layer are laminated, Barkhausen noise can be suppressed by applying a bias magnetic field in the easy magnetization direction of the magnetic layer. it can. This method uses a multilayer film including at least one magnetic layer having a coercive force different from other magnetic layers, a multilayer film including at least one magnetic layer having an anisotropic magnetic field different from other magnetic layers, and a magnetic layer between the magnetic layers when there is no external magnetic field. A magnetoresistive element including a multilayer film in which the magnetization directions of the magnetic layers are antiparallel due to exchange interaction, or a multilayer film in which at least one of the magnetic layers has an easy magnetization direction different from other magnetic layers. Can be applied. As a method of applying the bias magnetic field, a method of using a permanent magnet layer or a method of using an antiferromagnetic layer can be mentioned.

Further, the magnetoresistive effect element suppressing Barkhausen noise can be suitably used as a magnetic field sensor for detecting a magnetic field, a magnetic head for reproducing recorded information, and the like. Further, by combining a reproducing magnetic head composed of a magnetoresistive effect element with an inductive magnetic head for recording or erasing information, and mounting the magnetic recording, erasing or reproducing device on a magnetic recording and reproducing device, Barkhausen It is possible to realize a high-performance magnetic recording / reproducing device that suppresses noise. Since the magnetic head using the magnetoresistive effect element of the present invention exhibits high performance in recording / reproducing with a narrow track width, by applying this to a magnetic recording device, a high-performance magnetic disk having a high recording density can be obtained. A device can be realized

[0007].

In the magnetoresistive effect element using the multilayer film in which the magnetic layer and the non-magnetic layer are laminated according to the present invention, Barkhausen noise is generated by applying a bias magnetic field in the easy magnetization direction of the magnetic layer forming the multilayer film. Can be effectively suppressed. This method uses a multilayer film including at least one magnetic layer having a coercive force different from other magnetic layers, a multilayer film including at least one magnetic layer having an anisotropic magnetic field different from other magnetic layers, and a magnetic layer between the magnetic layers when there is no external magnetic field. Applied to a multilayer film in which the magnetization directions of the magnetic layers are antiparallel due to exchange interaction, or a magnetoresistive element having a multilayer film structure in which at least one of the magnetic layers has an easy magnetization direction different from other magnetic layers. can do. As a method of applying the bias magnetic field, there is a method of using a permanent magnet layer or a method of using an antiferromagnetic layer. Further, since the magnetoresistive effect element suppressing Barkhausen noise can exert high performance in recording / reproducing with a narrow track width as a magnetic field sensor, a reproducing magnetic head, etc., it can be used as an inductive magnetic head for recording or erasing. By combining the above, it becomes possible to realize a high-performance magnetic recording / reproducing apparatus having a high recording density without causing Barkhausen noise.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in more detail with reference to the drawings. [Example 1] A vacuum deposition method was used for manufacturing the multilayer film. The ultimate vacuum is 1/10 ⁸ Pa, and the film formation rate is 0.2 to
It was set to 0.6 nm / s. When forming a film, 2 parallel to the film surface
A magnetic field of 0 kA / m (250 Oersted) was applied.
As the substrate, 7059 glass manufactured by Corning Inc. was used. The cross-sectional structure of the formed multilayer film is shown in FIG. In the figure, the magnetic layers 1 and 2 have different coercive forces. In this embodiment, first, as a conventional example, the journal of
The Physical Society of Japan (J
individual of the Physical So
ciency of Japan), Vol. 59, No. 9,
3061-3064, "Magnetic reluctance effect of giant ferrimagnetic multilayer film induced by magnetic field (Large M
Aggregatorism of Field
-Induced Giant Ferrimagnet
ic Multilayers), a similar multilayer film as discussed in Co (3 nm) / Cu (5
nm) / Ni-Fe (3 nm) / Cu (5 nm)
Periodically laminated. That is, Co was used as the magnetic layer 1, Ni—Fe based alloy was used as the magnetic layer 2, and Cu was used as the non-magnetic layer 3. Using this multilayer film, a conventional magnetoresistive element shown in FIG. 3 was produced. As shown in the figure, the magnetoresistive effect element 6 has a structure in which an electrode 5 is provided at the end of the multilayer film 4. A magnetic field was applied to the conventional magnetoresistive effect element 6 to measure the magnetoresistive effect. The result is shown in FIG. In addition,
The application direction of the magnetic field was perpendicular to the current flow direction of the multilayer film 4. As shown in FIG. 4, Barkhausen noise due to domain wall motion in the magnetic layer was observed in the conventional magnetoresistive effect element 6. Next, using the multilayer film shown in FIG.
A magnetoresistive effect element 10 of the present invention shown in FIG. 1 was produced.
As shown in the figure, the magnetoresistive effect element 10 has a structure in which a permanent magnet layer 8 is laminated on the end portion of the multilayer film 7 and an electrode 9 is further laminated. In this embodiment, as the permanent magnet layer 8, Co
A -20 at (atom)% Pt alloy was used. A magnetic field of 800 kA / m [10 kOe (kilo-Oersted)] was applied in the longitudinal direction of the multilayer film 7 to magnetize the permanent magnet layer 8. A magnetic field lower than the coercive force of the permanent magnet was applied to the magnetoresistive element 10 to measure the magnetoresistive effect.
The result is shown in FIG. The magnetic field application direction was perpendicular to the current flow direction of the multilayer film 7. As shown in FIG. 5, in the magnetoresistive effect element 10 of the present invention, Barkhausen noise due to the domain wall motion in the magnetic layer did not occur at all. It is considered that this is because the magnetic field generated from the permanent magnet layer 8 is always applied in the longitudinal direction of the multilayer film 7 (the direction of easy magnetization of the multilayer film), and the magnetic domain wall is less likely to be generated in the multilayer film 7.

As described above, by applying the bias magnetic field in the direction of easy magnetization of the multilayer film having the magnetoresistive effect, Barkhausen noise of the magnetoresistive effect element using the multilayer film can be suppressed. Further, since it is preferable to apply a bias magnetic field uniformly to each magnetic layer in the multilayer film, it is desirable to use a permanent magnet layer as shown in this embodiment. Further, in the present embodiment, the Ni—Fe alloy and Co were used as the magnetic layer material, but even if two other materials having different coercive forces are used, the effect of suppressing the Barkhausen noise due to the application of the bias magnetic field is not essential. Obtained as in the example. Further, the same effect as above can be obtained by using a material other than Cu as the non-magnetic layer material. Although Co-20 at% Pt alloy is used as the permanent magnet layer 8 in this embodiment, the effect of suppressing Barkhausen noise can be obtained by using other permanent magnet materials. Further, in the present embodiment, the case where the bias magnetic field is applied only in the easy magnetization direction of the multilayer film has been described. However, in order to improve the sensitivity in the magnetic head or the like, the magnetic field detection direction (in the multilayer film of the present embodiment, the magnetization hard direction )
A bias magnetic field is often applied to. However, also in this case, as shown in the present embodiment, the effect of suppressing Barkhausen noise by applying a bias magnetic field in the direction of easy magnetization of the multilayer film is similarly obtained. Further, in this embodiment, the case where the multilayer film has two kinds of magnetic layers having different coercive forces was described, but the same result as above can be obtained even when the multilayer film has two kinds of magnetic layers having different anisotropic magnetic fields. Be done. Further, when the magnetoresistive effect exhibits hysteresis as shown in FIG. 5, when the magnetoresistive head of the above-mentioned multilayer film is used in a magnetic recording / reproducing apparatus, a high magnetic field is applied to the above-mentioned multilayer film to change the magnetization state. It is desirable to add a mechanism that can be initialized.

[Example 2] A high-frequency sputtering method was used for manufacturing a multilayer film. Ultimate vacuum is 1/1
0 ⁵ Pa, the film forming rate is about 0.02 nm / s. 20 kA / m (250 Oe) parallel to the film surface during film formation
Was applied. The board is made of Corning 7059.
Glass was used. The cross-sectional structure of the multilayer film in this example is shown in FIG. In the figure, the thickness of the magnetic layer 11 is 1.5.
nm Ni-20 at% Fe alloy, and Cu having a film thickness of 2.1 nm was used as the nonmagnetic layer 12. The magnetic layer 11 and the nonmagnetic layer 12 were laminated for 10 cycles. Further, a Fe layer having a film thickness of 5 nm was used as the buffer layer 13 on the substrate 14. This multi-layer film is a physical review letter (Physical Review) by Baibich et al.
wLetters), Volume 61, No. 21, No. 2472.
To "(001) Fe / (001) C" on page 2475.
Giant Magnetoresistance Effect of r Magnetic Superlattice "(Giant Ma
gnetrestance of (001) F
e / (001) CrMagnetic Superla
In the same manner as the Fe / Cr multi-layered film in the above, the magnetization directions of the respective magnetic layers are substantially antiparallel due to the exchange interaction between the magnetic layers in the absence of an external magnetic field. When the magnetoresistive effect element having the conventional structure shown in FIG. 3 was manufactured using the above-mentioned multilayer film in the same manner as in Example 1, Barkhausen noise was generated in the magnetoresistive effect curve as shown in FIG.
On the other hand, when the magnetoresistive effect element of the present invention having the structure shown in FIG.
Barkhausen noise was not observed as shown in. It is considered that this is because the magnetic field generated from the permanent magnet layer is always applied in the longitudinal direction of the multilayer film (the direction of easy magnetization of the multilayer film), and the domain wall is less likely to be generated in the multilayer film.

As described above, by applying the bias magnetic field in the direction of easy magnetization of the multilayer film having the magnetoresistive effect, Barkhausen noise of the magnetoresistive effect element using the multilayer film can be suppressed. In a multilayer film,
Since it is preferable to apply a bias magnetic field uniformly to each magnetic layer, it is desirable to use a permanent magnet layer as shown in this embodiment. Further, in the present embodiment, the Ni—Fe alloy is used as the magnetic layer material, but even if other magnetic materials are used, the magnetization directions of the magnetic layers are opposite due to the exchange interaction between the magnetic layers in the absence of an external magnetic field. If the multilayer film is oriented parallel,
The effect of suppressing Barkhausen noise by applying a bias magnetic field is similarly obtained. Even when the non-magnetic layer material is a material other than Cu, the same result as above can be obtained. In this example, the permanent magnet layer 8 was made of Co-20 at% Pt.
Although an alloy is used, the effect of suppressing Barkhausen noise can be similarly obtained by using another permanent magnet material. Further, in the present embodiment, the case where the bias magnetic field is applied only in the easy magnetization direction of the multilayer film has been described. Bias is often applied in the direction).
Even in this case, the effect of suppressing Barkhausen noise can be similarly obtained by applying a bias magnetic field in the easy magnetization direction as in the present invention. Further, as shown in FIG. 8, when the magnetoresistive effect exhibits hysteresis, a high magnetic field is applied to the multi-layered film when the magneto-resistive head including the multi-layered film is mounted on the magnetic recording / reproducing apparatus to reproduce recorded information. It is desirable to add a mechanism capable of applying a magnetic field to initialize the magnetization state.

[Example 3] A multilayer film was formed in the same manner as in Example 2. The cross-sectional structure of the multilayer film is shown in FIG. In this embodiment, the magnetic layer 15 is made of Ni-20 having a thickness of 1.5 nm.
At% Fe alloy and Ag having a thickness of 2.0 nm were used as the non-magnetic layer 16. The magnetic layer 15 and the non-magnetic layer 16 have 10
Periodically laminated. Further, an Fe layer having a film thickness of 5 nm was provided as the buffer layer 17 on the substrate 18. Further, by changing the direction of the magnetic field applied at the time of sputtering the magnetic layer 15, the easy magnetization directions of the magnetic layers 15 were made orthogonal to each other. In the multilayer film of this embodiment, when only the ferromagnetic layers are counted as shown in FIG. 10, the easy magnetization directions are perpendicular to the odd-numbered layers and the even-numbered layers. Therefore, when the angle θ of the magnetic field application direction is 45 degrees, for example, a magnetization process as shown in FIG. 11 is shown. However, the relationship between the magnitude of the applied magnetic field and the magnetization state differs depending on the coercive force and anisotropic magnetic field of the ferromagnetic layer. As shown in FIG. 11, the applied magnetic field changes the angle formed by the magnetization directions of the ferromagnetic layers, which causes the magnetoresistive effect. The maximum magnetic field is 520
It was as low as A / m (6.5 Oe), and the maximum magnetoresistance change rate was as high as 8.0%. Using the above multilayer film, FIG.
When the conventional magnetoresistive effect element shown in FIG. 2 was manufactured, Barkhausen noise was generated in the magnetoresistive effect curve. On the other hand, when the magnetoresistive effect element of the present invention having the structure shown in FIG. 1 was manufactured using the above-mentioned multilayer film, Barkhausen noise was not observed. It is considered that this is because the magnetic field generated from the permanent magnet layer is always applied in the longitudinal direction of the multilayer film, and the domain wall is less likely to be generated in the multilayer film.

As described above, by applying a bias magnetic field in the direction of easy magnetization in the shape of the entire multilayer film having the magnetoresistive effect, that is, in the direction perpendicular to the magnetic field detection direction, the magnetoresistive effect element using the multilayer film is obtained. Barkhausen noise can be suppressed. In a multilayer film, it is preferable to apply a bias magnetic field uniformly to each magnetic layer, and therefore it is desirable to use a permanent magnet layer as in this embodiment. In this embodiment, the Ni—Fe alloy is used as the magnetic layer material, but other magnetic materials may be used as long as the easy magnetization directions of the respective magnetic layers are orthogonal to each other. ,
The effect of suppressing Barkhausen noise by applying a bias magnetic field is similarly obtained. Further, the same result as above can be obtained by using a material other than Ag as the non-magnetic layer material. In this example, the permanent magnet layer 8 was made of Co-2.
Although the 0 at% Pt alloy was used, the Barkhausen noise suppressing effect can be similarly obtained by using other permanent magnet materials.
Further, in the present embodiment, the case where the bias magnetization is applied only in the direction perpendicular to the magnetic field detection direction of the multilayer film has been described, but in the case of applying a bias in the magnetic field detection direction in order to increase the sensitivity in a magnetic head or the like. There are many. Also in this case, the effect of suppressing Barkhausen noise can be similarly obtained by applying the bias magnetic field in the direction perpendicular to the magnetic field detection direction as in the present invention. Further, when the magnetoresistive effect exhibits hysteresis, a high magnetic field is applied to the multilayer film to reproduce the recorded information when the magnetoresistive head made of the multilayer film is mounted on the magnetic recording / reproducing apparatus to reproduce the magnetization state. It is desirable to add a mechanism that can be initialized. In this embodiment, the high frequency sputtering method was used for forming the multilayer film, but the same result can be obtained by using another thin film forming method. Further, although the case where the easy magnetization directions of the magnetic layers above and below the non-magnetic layer form a right angle in the present embodiment, it is not always necessary to form a right angle, and if it is 45 degrees or more, a magnetic resistance similar to that of the present embodiment is obtained. The effect is obtained.

Example 4 A magnetoresistive effect element using an antiferromagnetic layer as a layer for applying a bias magnetic field in a direction perpendicular to the magnetic field detection direction was manufactured. FIG. 12 shows the configuration of the magnetoresistive effect element 27 manufactured in this example. In the magnetoresistive effect element 27, the antiferromagnetic layer 25 is laminated on the multilayer film 24,
The structure is such that the electrodes 26 are formed at their ends. An Fe-50at% Mn alloy was used as the antiferromagnetic layer material. As the multilayer film, the multilayer film having the two types of magnetic layers having different coercive forces described in Example 1, the multilayer film having the two types of magnetic layers having different anisotropic magnetic fields, and the external magnetic field described in Example 2 When there is no magnetic field, the magnetization directions of the magnetic layers are antiparallel due to the exchange interaction between the magnetic layers, and the easy magnetization directions of the magnetic layers described in the third embodiment are orthogonal to each other. It was possible to confirm the effect of suppressing Barkhausen noise by the bias magnetic field from the antiferromagnetic layer in any of the multilayer films. However, when an antiferromagnetic layer is used, the Barkhausen noise cannot be completely suppressed because a bias is not uniformly applied to each magnetic layer. Further, in the present embodiment, the Fe-50at% Mn alloy was used as the antiferromagnetic layer material, but the same effect can be obtained by using other materials as long as the material exhibits antiferromagnetism at room temperature.

[Embodiment 5] A multilayer film was formed in the same manner as in Embodiment 2. As the magnetic layer 15 in FIG.
A Ni-20 at% Fe alloy having a thickness of 5 nm and Ag having a thickness of 2.0 nm were used as the nonmagnetic layer 16. The magnetic layer 15 and the non-magnetic layer 16 were laminated for 10 cycles. Further, as the buffer layer 17 on the substrate 18, a Fe layer having a film thickness of 5 nm was used. Further, by changing the direction of the magnetic field applied during the sputtering of the magnetic layers, the easy magnetization directions of the magnetic layers 15 were made orthogonal to each other. A yoke type magnetoresistive effect element was formed as the magnetoresistive effect element using the multilayer film. The manufacturing process of the magnetoresistive effect element will be described below. Figure 1
As shown in FIG. 4A, a magnetic shield layer 29 was formed on a non-magnetic substrate 28 made of a sintered body containing Al ₂ O ₃ .TiC as a main component. The magnetic shield layer 29 is formed by a sputtering method and has a film thickness of 1 μm.
Malloy) was used. Also, on the magnetic shield layer 29,
The insulating layer 30 made of Al ₂ O ₃ having a film thickness of 0.2 μm was formed by the sputtering method. Further, as shown in FIG. 14 (b), two Ni—Zn ferrite plates 31 and a glass 32 are provided.
A yoke plate 34 having a gap 33 was prepared, and the thickness of the yoke plate 34 was ground to the track width. As shown in FIG. 14C, the multilayer film 3 is formed on the yoke plate 34.
5, a permanent magnet layer 36, and a shunt film 37 made of a Ti film having a film thickness of 30 nm are formed by a sputtering method, and Cr is formed.
A lead wire 38 having a multilayer structure of / Cu / Cr was formed. It is more preferable to use Nb as the shunt film 37 because the heat resistance in the magnetic head forming process is improved. The magnetoresistive effect element 39 thus obtained was stacked on the insulating layer 30 as shown in FIG. Then, as shown in FIG. 14 (e),
After forming an insulating layer 40 made of Al ₂ O ₃ and flattening it, a magnetic shield layer 41 made of a Ni—Fe based alloy having a film thickness of 1 μm was formed to obtain a magnetoresistive effect element 42. The magnetoresistive effect element 42 is shielded in the track width direction 43 as well.
The rudder layer is provided. Therefore, the magnetic head using the magnetoresistive effect element of the present invention is less likely to be affected by the signal magnetic field from the adjacent track. Further, in the yoke type magnetoresistive effect element as in the present embodiment, the shape of the multilayer film can be freely configured. The multilayer film in which the easy magnetization directions of the magnetic layers are orthogonal to each other as in this embodiment is preferably a square from the viewpoint of reducing the influence of the shape magnetic anisotropy. From this point, it can be said that the yoke type magnetoresistive effect element is suitable for a multilayer film in which the easy magnetization directions of the magnetic layers are orthogonal to each other. By the way, although the shunt bias method is shown as the bias method for the magnetoresistive film in this embodiment, other bias methods such as a permanent magnet method and a soft bias method can also be used. Further, by combining the magnetoresistive effect element and the inductive magnetic head for recording, a high-performance composite magnetic head can be constructed. Further, since the magnetic head of the present invention exhibits high performance in recording / reproducing with a narrow track width, by using the magnetic head of the present invention in a magnetic disk device, a high-performance magnetic disk device having a high recording density can be obtained. It can be realized.

[Sixth Embodiment] A magnetic head was manufactured using the magnetoresistive element described in the third embodiment. 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. In the magnetoresistive film 44 using a multilayer film, the portion sandwiched by the shield layers 45 and 46 serves as a reproducing head, and the two recording magnetic poles 48 and 49 sandwiching the coil 47 serve as a recording head. The magnetoresistive film 44 is composed of the multilayer film described in the third embodiment.
Further, a permanent magnet layer 52 was laminated on the end portion of the multilayer film in order to apply a bias magnetic field in a direction perpendicular to the magnetic field detection direction. Further, a shunt film 51 made of Nb was formed on the multilayer film in order to apply a bias magnetic field in the magnetic field detection direction. Further, for the electrode 53, an electrode material having a multilayer structure of Cr / Cu / Cr was used. The method of manufacturing this head will be described below. A sintered body containing Al ₂ O ₃ .TiC as the main component was used as the base body 50 for the slider. The shield layers 45 and 46 and the recording magnetic poles 48 and 49 are formed by sputtering Ni.
-Fe alloy was used. The thickness of each magnetic film was as follows. The upper and lower shield layers 45 and 46 are 1.0 μm, the recording magnetic poles 48 and 49 are 3.0 μm, and the total thickness of the multilayer film is 40 μm.
nm. As the gap material between the film layers, Al ₂ O ₃ formed by the sputtering method was used. The film thickness of the gap layer is 0.2 μm between the shield layer and the magnetoresistive effect element,
The distance between the recording magnetic poles was 0.4 μm. Further, the distance between the reproducing head and the recording head is set to about 4 μm, and this gap is also made of Al.
_It was formed of ₂ O ₃ . Cu having a film thickness of 3 μm was used for the coil 47. When recording / reproducing was performed with the magnetic head having the structure described above, a high reproducing output 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 and applies an appropriate bias magnetic field.
Although the shunt bias method is used as the bias method in the above embodiment, the same effect can be obtained by using another bias method such as the current bias method, the permanent magnet method, the soft bias method, and the mutual bias method. Be done.

By the way, when the magnetic head has recording and reproducing capabilities at the same time, when a recording element is formed in a portion close to the substrate, a large step is formed above the recording element due to formation of a coil, a magnetic pole and the like. Occurs. It is not preferable to form a multi-layered magnetoresistive film on this, because the multi-layered structure is disturbed by the effect of the step. On the other hand, as shown in FIG. 14, when the magnetoresistive effect element for reproduction is formed in the portion close to the substrate, the magnetoresistive effect element is formed in the portion having a relatively small step, so that the disorder of the multilayer structure hardly occurs. Become. This is a phenomenon that is essentially different from the magnetoresistive effect element using the permalloy single layer film. From the above viewpoints, when the magnetic head has recording and reproducing capabilities at the same time, it is desirable to form a reproducing magnetoresistive effect element in a portion near the substrate. From the same point of view, by forming the recording element and the reproducing magnetoresistive effect element at another place on the same substrate, the magnetoresistive effect element can be formed in a portion having a small step. Further, by using the magnetoresistive effect element described in Examples 1 and 2, it is possible to obtain a magnetic head capable of reproducing with high sensitivity. Further, the magnetoresistive effect element of the present invention can be used in a magnetic field detector other than the magnetic head. By using the above magnetic head in a magnetic recording / reproducing apparatus, a high-performance magnetic recording / reproducing apparatus having a high recording density can be realized.

[0018]

INDUSTRIAL APPLICABILITY As described above, in a magnetoresistive effect element using a multilayer film in which non-magnetic layers are laminated, Barkhausen noise is suppressed by applying a bias magnetic field in the direction of easy magnetization of the magnetic layer. You can This method includes a multi-layer film including at least one magnetic layer having a coercive force different from other magnetic layers, a multi-layer film including at least one magnetic layer having an anisotropic magnetic field different from other magnetic layers, and a magnetic layer between the magnetic layers in the absence of an external magnetic field. Applied to a magnetoresistive element including a multilayer film in which the magnetization directions of the magnetic layers are antiparallel due to exchange interaction, or at least one of the magnetic layers has a different easy magnetization direction than other magnetic layers. it can. Methods of applying the bias magnetic field include a method of using a permanent magnet layer and a method of using an antiferromagnetic layer. Further, the magnetoresistive effect element in which Barkhausen noise is suppressed is suitably used as a magnetic field sensor or a magnetic head that exhibits high performance in magnetic recording / reproducing with a narrow track width. Further, by using it in combination with an induction type magnetic head for magnetic recording and erasing, it is possible to realize a high performance magnetic recording / reproducing apparatus with high recording density.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a magnetoresistive effect element exemplified in a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a cross-sectional structure of a multilayer film of the magnetoresistive effect element shown in FIG.

FIG. 3 is a perspective view showing a structure of a conventional magnetoresistive effect element.

FIG. 4 is a graph showing a magnetoresistive effect of a conventional magnetoresistive effect element.

FIG. 5 is a graph showing the magnetoresistive effect of the magnetoresistive element illustrated in Example 1 of the present invention.

FIG. 6 is a schematic diagram showing a cross-sectional structure of a multilayer film of the magnetoresistive effect element exemplified in Example 2 of the present invention.

FIG. 7 is a graph showing a magnetoresistive effect of a conventional magnetoresistive effect element.

FIG. 8 is a graph showing the magnetoresistive effect of the magnetoresistive effect element exemplified in Example 2 of the present invention.

FIG. 9 is a schematic diagram showing a cross-sectional structure of a multilayer film of the magnetoresistive effect element exemplified in Example 3 of the present invention.

10 is a plan view showing the easy magnetization direction of the multilayer film shown in FIG.

FIG. 11 is an explanatory diagram showing a magnetization process of the multilayer film shown in FIG. 9.

FIG. 12 is a perspective view showing the configuration of a magnetoresistive effect element exemplified in Example 4 of the present invention.

FIG. 13 is an explanatory diagram showing a manufacturing process of the magnetoresistive effect element exemplified in Example 5 of the present invention.

FIG. 14 is a perspective view showing the structure of the magnetic head exemplified in the sixth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetic layer 2 ... Magnetic layer 3 ... Nonmagnetic layer 4 ... Multilayer film 5 ... Electrode 6 ... Magnetoresistive effect element 7 ... Multilayer film 8 ... Permanent magnet layer 9 ... Electrode 10 ... Magnetoresistive effect element 11 ... Magnetic layer 12 ... Non-magnetic layer 13 ... Buffer layer 14 ... Substrate 15 ... Magnetic layer 16 ... Non-magnetic layer 17 ... Buffer layer 18 ... Substrate 19 ... Easy magnetization direction of odd-numbered magnetic layer 20 ... Easy magnetization direction of even-numbered magnetic layer 21 ... Magnetic field application direction 22 ... Magnetization direction of odd-numbered magnetic layer 23 ... Magnetization direction of even-numbered magnetic layer 24 ... Multilayer film 25 ... Antiferromagnetic layer 26 ... Electrode 27 ... Magnetoresistive element 28 ... Non-magnetic substrate 29 ... Magnetic shield layer 30 ... Insulating layer 31 ... Ni-Zn ferrite substrate 32 ... Glass 33 ... Gap 34 ... Yoke plate 35 ... Multilayer film 36 ... Permanent magnet layer 37 ... Shunt film 38 ... Re- Wire 39 ... Magnetoresistive effect Child 40 ... Insulating layer 41 ... Magnetic shield layer 42 ... Magnetoresistive effect element 43 ... Track width direction 44 ... Magnetoresistive effect film 45 ... Shield layer 46 ... Shield layer 47 ... Coil 48 ... Recording magnetic pole 49 ... Recording magnetic domain 50 ... Substrate 51 ... Shunt film 52 ... Permanent magnet layer 53 ... Electrode

Claims (11)

[Claims] 1. A magnetoresistive effect element constituted by using a magnetoresistive effect film composed of a multilayer film in which a magnetic layer and a non-magnetic layer are laminated, and detecting a direction of easy magnetization or a magnetic field of the magnetoresistive effect film composed of the multilayer film. A magnetoresistive effect element comprising at least means for applying a bias magnetic field in a direction perpendicular to the direction. 2. The magnetoresistive effect film comprising the multilayer film according to claim 1, wherein at least one magnetic layer having a coercive force different from that of other magnetic layers is laminated. 3. A magnetoresistive effect film comprising the multilayer film according to claim 1, wherein at least one magnetic layer having an anisotropic magnetic field different from that of other magnetic layers is laminated. 4. The magnetoresistive film comprising the multilayer film according to claim 1, wherein the magnetization directions of the magnetic layers are substantially antiparallel due to exchange interaction between the magnetic layers forming the multilayer film in the absence of an external magnetic field. A magnetoresistive effect element characterized by being oriented. 5. The magnetoresistive film comprising the multilayer film according to claim 1, wherein at least one of the magnetic layers constituting the multilayer film is formed.
A magnetoresistive element, wherein the layer has an easy magnetization direction different from other magnetic layers. 6. A magnetoresistive effect element comprising a multilayered magnetoresistive effect film according to claim 1, wherein the bias magnetic field applying means is a permanent magnet layer. 7. A magnetoresistive effect element comprising a multilayered magnetoresistive effect film according to claim 1, wherein the bias magnetic field applying means is an antiferromagnetic layer. 8. A magnetic field sensor comprising a magnetic field detector using the magnetoresistive effect element according to any one of claims 1 to 7. 9. A magnetic head comprising a magnetoresistive effect element according to claim 1 for constituting a reproducing magnetic head for reproducing recorded information. 10. A magnetic recording, erasing or recording method using a combination of a reproducing magnetic head using the magnetoresistive element according to claim 1 and an induction type magnetic head for recording or erasing. A magnetic head comprising a composite magnetic head for reproducing. 11. A magnetic recording / reproducing apparatus comprising the magnetic head according to claim 9 or 10 mounted on a magnetic recording / reproducing apparatus, and at least means for performing magnetic recording, erasing or reproducing.