JPH10335714A - Magnetoresistance effect element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the production of Barkhausen noise in the element operation time, by reducing the turbulence in the magnetizing direction of a magnetic domain controlling film by an outer magnetic field. SOLUTION: A magnetoresistance effect element is provided with a magnetoresistance effect film 1 for detecting the outer magnetic field as well as a magnetic domain controlling film 10 almost in vertical direction to the detecting magnetic field of the outer magnetic field also in the direction along the film surface. At this time, the magnetic domain controlling film 10 is also provided with the shape anisotropy aligning the magnetic moment of the film 10 in the magnetizing direction A, so as to reduce the turbulence of the film 10 by the outer magnetic field. Accordingly, the production of Barkhausen noise in the element operation time can be suppressed, thereby enabling the title magnetoresistance effect element having the excellent element output characteristics to be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element having a magnetoresistive film for detecting an external magnetic field and a magnetic domain control film for controlling magnetic domains of the magnetoresistive film.

[0002]

2. Description of the Related Art A magnetoresistive element is an element for measuring a magnetic field strength and its change by detecting a change in the magnetoresistance of a magnetoresistive film caused by application of an external magnetic field. It is being studied as a reproducing head of a hard disk device.

As a magnetoresistive film, a film exhibiting an anisotropic magnetoresistive (AMR) effect such as NiFe, or having a structure in which a ferromagnetic layer and a nonmagnetic conductive layer are laminated, has higher sensitivity than an AMR film. Films exhibiting the giant magnetoresistance (GMR) effect shown are known.

In these magnetoresistive films, when an external magnetic field is applied, the magnetization state of the magnetoresistive film changes, and accordingly, magnetic domains are generated in the magnetic layer of the magnetoresistive film. It is known that when it moves, the magnetic resistance changes discontinuously, and so-called Barkhausen noise occurs. In order to suppress the generation and movement of magnetic domains that cause such Barkhausen noise, a bias magnetic field is applied to the magnetoresistive film by providing a magnetic domain control layer on the side of the magnetoresistive film. Conventionally, a method of suppressing the occurrence of Barkhausen noise has been generally performed.

Generally, a magnetic domain control film is magnetized in a direction perpendicular to an external magnetic field to be detected by applying a magnetic field at the time of fabrication. The magnetoresistive film has a stable single magnetic domain structure due to the bias magnetic field of the magnetic domain control film, and generation of magnetic domains is suppressed.

[0006]

However, during actual device operation, an external magnetic field is also applied to the magnetic domain control film,
Since this external magnetic field is in a direction perpendicular to the magnetization direction of the magnetic domain control film, the magnetization direction of the magnetic domain control film is disturbed. As a result, the effect of suppressing Barkhausen noise is reduced, and Barkhausen noise is generated. was there.

An object of the present invention is to provide a magnetoresistive element capable of reducing disturbance of the magnetization direction of a magnetic domain control film due to an external magnetic field and suppressing the occurrence of Barkhausen noise during element operation.

[0008]

A magnetoresistive element according to the present invention has a magnetoresistive film for detecting an external magnetic field, and a direction substantially perpendicular to the direction of the detected magnetic field of the external magnetic field and along the film surface. A magnetic domain control film for controlling the magnetic domain of the magnetoresistive film, which is magnetized in the direction, and imparts shape anisotropy to the magnetic domain control film to align the magnetic moment of the magnetic domain control film with the magnetization direction. It is characterized by having.

In one preferred embodiment according to the present invention, by making the length of the magnetization direction of the magnetic domain control film longer than the length in the direction perpendicular to the magnetization direction, the shape of the magnetic domain control film is anisotropic. Is given. The length of the magnetization direction of the magnetic domain control film is more preferably set to be twice or more the length in the direction perpendicular to the magnetization direction.

In another preferred embodiment according to the present invention, the shape anisotropy is imparted by forming a groove extending in the magnetization direction in the magnetic domain control film. The groove extending in the magnetization direction may be a through groove extending from one end to the other end of the magnetic domain control film, or may be a groove in which a part of the magnetic domain control film is cut out so as to extend in the magnetization direction. .

In the present invention, the magnetic domain control film is, for example,
It is formed from a hard magnetic layer made of a hard magnetic material. Examples of such a hard magnetic material include CoCrPt and CoPt.

Further, the magnetic domain control film may be formed of a laminated structure of an antiferromagnetic layer and a soft magnetic layer. As the antiferromagnetic layer, for example, NiMn, FeMn, NiO, IrM
n, PtMn, PdPtMn and the like. Also,
As the soft magnetic layer, for example, NiFe, NiFeCr,
NiFeCo, CoFe, CoFeB, and the like.

When the magnetic domain control film is formed of a laminated structure of an antiferromagnetic layer and a soft magnetic layer, irregularities are formed at the interface between the antiferromagnetic layer and the soft magnetic layer, and the concave and convex portions extend in the direction of magnetization. By being formed as described above, the magnetic domain control film may be provided with the shape anisotropy. In the present invention,
The shape anisotropy may be provided by combining the above-described methods.

The magnetoresistive film of the present invention is not particularly limited as long as it is a magnetic film exhibiting a magnetoresistive effect. For example, an AMR effect film or a GMR effect film can be used. As the GMR film, a spin-valve type laminated film having a ferromagnetic layer / non-magnetic conductive layer / ferromagnetic layer / antiferromagnetic layer as a basic structural unit, and a ferromagnetic layer / non-magnetic conductive layer / ferromagnetic layer as a basic structure As a unit, a laminated film of a coercive force difference type in which ferromagnetic layers differ from each other in a coercive force, an artificial lattice type laminated film in which a ferromagnetic layer / a nonmagnetic conductive layer is repeatedly laminated many times, and the like. In a nonmagnetic conductive layer of Cu, Ag, etc., C
A particle GMR effect film in which ferromagnetic particles such as o and Fe are dispersed can also be used.

In the present invention, the position at which the magnetic domain control film is provided is not particularly limited as long as a bias magnetic field can be applied to the magnetoresistive film in order to control the magnetic domains of the magnetoresistive film. In general, a pair of magnetic domain control films are provided on both sides of the magnetoresistive film so as to sandwich the magnetoresistive film.

According to the present invention, the shape anisotropy that aligns the magnetic moment of the magnetic domain control film in a direction substantially perpendicular to the direction of the detected magnetic field of the external magnetic field and along the film surface is controlled. Applied to the membrane. For this reason, even when an external magnetic field is applied in a direction substantially perpendicular to the magnetization direction of the magnetic domain control film during element operation, disturbance of magnetization in the magnetic domain control unit can be reduced. Therefore, generation of Barkhausen noise during operation of the element can be suppressed.

[0017]

FIG. 1 is a perspective view showing a magnetoresistive element according to an embodiment of the present invention. Referring to FIG. 1, a magnetic domain control film 1 is provided on both sides of the magnetoresistive effect film 1.
0 is provided. The magnetoresistive film 1 is made of NiFeC
Lateral bias film (SAL film) made of r (thickness 130 °)
2. Magnetic separation film 3, made of Ta (film thickness 120 °), Ni
The magnetic film 4 made of Fe (film thickness 180 °) and the protective film 5 made of Ta (film thickness 40 °) are stacked in this order. Each thin film is formed by an RF sputtering method.

The magnetic domain control film 10 is made of NiMn (thickness 300
Ｎｉ) on the antiferromagnetic layer 11 made of
0 °). Note that these layers are formed by an RF sputtering method.

The magnetic domain control film 10 is magnetized in a direction indicated by an arrow A in FIG. The magnetization direction A is a direction substantially perpendicular to the detection magnetic field direction B of the external magnetic field detected by the magnetoresistive film 1. A bias magnetic field is applied to the magnetoresistive film 1 by the magnetic domain control film 10 magnetized in this way, and the magnetic domains are controlled so that the magnetoresistive film has a single magnetic domain structure.

In this embodiment, the length d of the magnetic domain control film 10 in the longitudinal direction (magnetization direction) is set to be longer than the width w of the magnetic domain control film 10, and is twice as large as the width w. Is set as described above. In this embodiment, the magnetic domain control film 10 is given shape anisotropy by making the length of the magnetization direction A longer than the width w. Due to such shape anisotropy, even when an external magnetic field is applied in the B direction, disturbance of the magnetization direction in the magnetic domain control film 10 is reduced, and Barkhausen noise can be suppressed.

FIG. 2 is a perspective view showing a magnetoresistive element of another embodiment according to the present invention. The magnetoresistive film 1 has the same configuration as the embodiment shown in FIG. Magnetic domain control film 2
0 is formed by laminating a soft magnetic layer 22 on an antiferromagnetic layer 21, similarly to the magnetic domain control film 10 of the embodiment shown in FIG. 1, and further extends in the magnetization direction in this embodiment. Grooves 23 and 24 are formed. The magnetic domain control film 20 of the present embodiment is set so that the length in the magnetization direction is twice the width, as in the embodiment shown in FIG. Therefore,
Shape anisotropy is imparted by adopting such dimensions and shape, and shape anisotropy is imparted by forming grooves 23 and 24 extending in the magnetization direction.
Therefore, the shape anisotropy is given to a greater degree than in the embodiment shown in FIG.

In this embodiment, the grooves 23 and 24 are formed so as to penetrate from the upper end to the lower end of the magnetic domain control film 20, and the grooves 23 and 24 are formed in both the antiferromagnetic layer 21 and the soft magnetic layer 22. 24 are formed. By forming such grooves 23 and 24, the antiferromagnetic layer 21 and the soft magnetic layer 22 are formed as stripe-shaped portions, and since the width of these stripe-shaped portions is reduced, the ratio of the length to the width is further increased. growing. Therefore, greater shape anisotropy can be provided.

In the embodiment shown in FIG. 2, the grooves 23 and 24 are formed in both the antiferromagnetic layer 21 and the soft magnetic layer 22, but even if the grooves 23 and 24 are formed in only one of them,
Shape anisotropy can be imparted. Antiferromagnetic layer 2
Shape anisotropy can also be imparted to a groove in which one or the soft magnetic layer 22 is partially cut out in the depth direction.

FIG. 3 is a perspective view showing a magnetoresistive film of another embodiment according to the present invention. The magnetoresistive film 1 in this embodiment is also configured in the same manner as the embodiment shown in FIG. 1 and the embodiment shown in FIG. The magnetic domain control film 30 has a structure in which a soft magnetic layer 32 is laminated on an antiferromagnetic layer 31, as in the embodiment shown in FIG. 1 and the embodiment shown in FIG. Irregularities are formed, and convex portions 33 and 34 and concave portions 35 are formed. These convex portions 33 and 34 and concave portion 35 are formed so as to extend in the magnetization direction of the magnetic domain control film 30.

The magnetic domain control film 30 of this embodiment is also set such that the length in the magnetization direction is twice the width, similarly to the embodiment shown in FIG. 1 and the embodiment shown in FIG. Gives shape anisotropy. In the present embodiment, the shape anisotropy is further provided by the protrusions 33 and 34 and the recess 35 extending in the magnetization direction formed at the interface between the antiferromagnetic layer 31 and the soft magnetic layer 32. Therefore, the shape anisotropy is given to a greater degree than in the embodiment shown in FIG.

FIGS. 4 to 6 are views showing steps of manufacturing the magnetoresistive film of the embodiment shown in FIG. The left side shows a plan view, and the right side shows a cross-sectional view. The cross-sectional view is a cross-sectional view taken along a dashed line in the plan view.

Referring to FIG. 4A, a magnetoresistive film 1 is formed on a substrate 40 made of AlTiC or silicon, for example, by an RF sputtering method. As described with reference to FIG. 1, the magnetoresistive film 1 is a laminated film in which a lateral bias film, a magnetic separation film, a magnetic film, and a protective film are laminated.

Referring to FIG. 4B, a resist film 41 is formed in a pattern shape as shown in a plan view by photolithography. Next, referring to FIG. 4C, the resistive film 41 is used as a mask to remove the magnetoresistive effect film 1 by etching to form a predetermined pattern.

Next, referring to FIG. 5D, a magnetic domain control film 10 is formed on the entire surface. As shown in the cross-sectional view, the domain control film 10 is formed on the resist film 41 where the resist film 41 is present, and the magnetic domain control film 10 is formed on the substrate 40 where the resist film 41 is not present. .

Next, referring to FIG. 5E, the resist film 41 is removed, and the magnetic domain control film 10 on the resist film 41 is removed by a so-called lift-off method. Next, referring to FIG. 5F, a resist film 42 having a pattern shape as shown in a plan view is formed. This resist film 42 is formed on a region where the magnetoresistive film 1 and the magnetic domain control film 10 are finally formed.

Referring to FIG. 5G, using the resist film 42 as a mask, the other region is etched away.
Referring to FIG. 6H, by removing the resist film 42, the magnetoresistive film 1 and the magnetic domain control film 10 are formed in predetermined regions.

Referring to FIG. 6I, a resist film 43 having a pattern shape as shown in a plan view is formed. Next, referring to FIG. 6J, after forming an electrode layer on the entire surface, the resist film 43 is removed, and an electrode layer 45 is formed at a predetermined location by a lift-off method. Here, as an electrode layer, a Ru layer (thickness 100 °) / W layer (thickness 10)
00Å) / Ru layer (100Å) is formed.

As described above, an element having a structure in which electrodes are provided on the magnetoresistive element shown in FIG. 1 is obtained. 7 to 9 are views showing the steps of manufacturing the magnetoresistive element of the embodiment shown in FIG. 2, wherein the left side is a plan view and the right side is a sectional view. The cross-sectional view is a cross-sectional view taken along a dashed line in a plan view.

As shown in FIG. 7A, the magnetoresistive film 1 is formed on the entire surface of the substrate 40. As shown in FIG. 7B, a resist film 51 having a predetermined pattern as shown in a plan view is formed on the magnetoresistive film 1 by using a photolithography method.

As shown in FIG. 7C, a resist film 51 is formed.
Is used as a mask to etch away the magnetoresistive effect film 1 in other areas. As shown in FIG. 8D, a magnetic domain control film 20 is formed on the entire surface. Where the resist film 51 exists, the magnetic domain control film 20 is formed on the resist film 51.
Is formed, and the magnetic domain control film 20 is formed on the substrate 40 in a portion where the resist film 51 does not exist.

As shown in FIG. 8E, a resist film 51 is formed.
Is removed, and the magnetic domain control film 20 on the resist film 51 is removed by a wrist-off method. As shown in FIG. 8F, a resist film 52 having a predetermined pattern shape as shown in a plan view.
Is formed by a photolithography method.

As shown in FIG. 8G, a resist film 52 is formed.
Is used as a mask to etch away other areas. As shown in FIG. 9H, by removing the resist film 52, the magnetoresistive film 1 and the magnetic domain control film 20 are formed in a predetermined shape on the substrate 40 in a predetermined shape.

As shown in FIG. 9I, a resist film 53 having a pattern shape as shown in a plan view is formed by photolithography. As shown in FIG. 9J, after forming an electrode layer on the entire surface, the resist film 53 is removed, and an electrode layer 55 having a predetermined pattern is formed by a lift-off method.

Through the above steps, an element having electrodes provided on the magnetoresistive element of the embodiment shown in FIG. 2 is obtained. In the magnetoresistive element of the embodiment shown in FIG. 3, after forming the antiferromagnetic layer 31 in the manufacturing process of the magnetic domain control film 30, the photolithography method using the above-described resist material and the etching technique are used. By etching and removing a predetermined portion of the antiferromagnetic layer 31 to a predetermined depth, forming the convex portions 33 and 34 and the concave portion 35 on the antiferromagnetic layer 31, and then laminating the soft magnetic layer 32 thereon, Can be manufactured.

The manufacturing method of each of the above embodiments is merely an example, and other manufacturing methods can be used. FIG. 10 is a diagram showing the magnetic field-voltage characteristics of the magnetoresistive element of the embodiment shown in FIG. FIG.
FIG. 7 is a diagram illustrating a magnetic field-voltage characteristic of a magnetoresistive element of a comparative example. 10 and 11, the vertical axis is an arbitrary unit. The magnetoresistive element of the comparative example is the same as the magnetoresistive element of the embodiment shown in FIG. 1 except that the width w of the magnetic domain control unit 10 and the length d of the magnetization direction are the same. As is clear from the comparison between FIG. 10 and FIG. 11, in the magnetoresistive effect element according to the example according to the present invention, the generation of Barkhausen noise is suppressed, and the linearity of the element output is improved. .

The magnetoresistance effect element of the present invention is not limited to the structure and material of the magnetoresistance effect element of each of the above embodiments, and other structures and materials can be applied. For example, in each of the above embodiments, a laminated structure in which a soft magnetic layer and an antiferromagnetic layer are laminated is shown as an example of a magnetic domain control film. For example, a hard magnetic layer made of a hard magnetic material such as CoCrPt may be used as a magnetic domain control film. It may be formed as a control film. Also, in each of the above embodiments, the AMR
Although the effect film is exemplified, a GMR effect film such as a spin valve type may be used as the magnetoresistive film, or a particle GMR effect film in which ferromagnetic particles are dispersed in a nonmagnetic conductive layer may be used as the magnetoresistive film. May be used.

[0042]

According to the magnetoresistive element of the present invention, the magnetic domain control film is provided with shape anisotropy for aligning the magnetization direction, thereby reducing the disturbance of the magnetization direction of the magnetic domain control film due to an external magnetic field. . Accordingly, it is possible to suppress the occurrence of Barkhausen noise during the operation of the element, and it is possible to obtain a magnetoresistive element having excellent element output characteristics.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a magnetoresistive element of one embodiment according to the present invention.

FIG. 2 is a perspective view showing a magnetoresistive element of another embodiment according to the present invention.

FIG. 3 is a perspective view showing a magnetoresistive element according to still another embodiment according to the present invention.

4A and 4B are a plan view (left side) and a cross-sectional view (right side) showing a manufacturing process of the magnetoresistive element of the embodiment shown in FIG.

5A and 5B are a plan view (left side) and a cross-sectional view (right side) showing a manufacturing process of the magnetoresistive element of the embodiment shown in FIG.

6A and 6B are a plan view (left side) and a cross-sectional view (right side) showing a manufacturing process of the magnetoresistive element of the embodiment shown in FIG.

7A and 7B are a plan view (left side) and a cross-sectional view (right side) showing a manufacturing process of the magnetoresistive element of the embodiment shown in FIG.

8A and 8B are a plan view (left side) and a cross-sectional view (right side) showing the manufacturing process of the magnetoresistive element of the embodiment shown in FIG.

9A and 9B are a plan view (left side) and a cross-sectional view (right side) showing the manufacturing process of the magnetoresistive element of the embodiment shown in FIG.

FIG. 10 is a view showing a magnetic field-voltage characteristic of the magnetoresistive element of the embodiment shown in FIG. 2;

FIG. 11 is a diagram showing a magnetic field-voltage characteristic of a magnetoresistive element of a comparative example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetoresistance effect film 2 ... Transverse bias film 3 ... Magnetic separation film 4 ... Magnetic film 5 ... Protective film 10,20,30 ... Magnetic domain control film 11,21,31 ... Antiferromagnetic layer 12,22,32 ... Soft Magnetic layers 23, 24 ... Grooves formed in magnetic domain control film 33, 34 ... Protrusions formed at interface in magnetic domain control film 35 ... Depressed portions formed at interface in magnetic domain control film 41-43 ... Resist film 45 ... Electrode layers 51-53 ... Resist film 55 ... Electrode layer

Continued on the front page (72) Inventor Fumio Tachien 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Hitoshi Noguchi 2-5-2-5 Keihanhondori, Moriguchi-shi, Osaka No. Sanyo Electric Co., Ltd.

Claims (7)

[Claims] 1. A magnetoresistive film for detecting an external magnetic field, wherein said magnetoresistive film is magnetized in a direction substantially perpendicular to a direction of a magnetic field detected by said external magnetic field and along a film surface. A magnetoresistive element comprising a magnetic domain control film for controlling magnetic domains, wherein the magnetic domain control film is provided with shape anisotropy for aligning a magnetic moment of the magnetic domain control film in the magnetization direction. A magnetoresistive element comprising: 2. The shape anisotropy is imparted to the magnetic domain control film by making the length of the magnetic domain control film longer in a direction perpendicular to the magnetization direction. The magnetoresistance effect element according to claim 1, wherein: 3. The shape of the magnetic domain control film is such that the shape anisotropy is reduced by setting the length of the magnetic domain control film in the magnetization direction to be at least twice the length in the direction perpendicular to the magnetization direction. The magnetoresistive element according to claim 1, wherein the element is provided. 4. The magnetic domain control film is provided with the shape anisotropy by forming a groove extending in the magnetization direction in the magnetic domain control film.
The magnetoresistive element according to any one of the above items. 5. The magnetoresistive element according to claim 1, wherein the magnetic domain control film is formed from a hard magnetic layer. 6. The magnetoresistance effect element according to claim 1, wherein said magnetic domain control film is formed of a laminated structure of an antiferromagnetic layer and a soft magnetic layer. 7. An uneven shape is formed at an interface between the antiferromagnetic layer and the soft magnetic layer, and a concave portion and a convex portion are formed so as to extend in the magnetization direction. The magnetoresistance effect element according to claim 6, wherein the magnetoresistance effect element is provided.