JPH118424A - Magnetoresistive effect element and magneticresistive effect-type head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase an MR ratio by providing a metallic reflection film that can easily generate reflected scattering, while maintaining the spin direction of an electron on the surface of a spin valve film. SOLUTION: A metallic reflection film 6 is added to the configuration of a basic spin valve film in a configuration of a soft magnetic film 3, a non- magnetic 4, and a hard magnetic property film 5. For example, Ag, Au, Bi, Sn, and Pb and the like should be used for the metal reflection film 6, and a level of several angstroms is measured on the surface for forming a smooth surface. Ag and Au are especially superior, and Ag is most effective. Therefore, a large number of conductive electrons are subjected to specular reflection on the surface of the metallic reflection film 6, and relatively spin information is maintained. In this manner, when electrons is subjected to the specular reflection on the thin film surface, the same effect as one where a magnetic property layer/non-magnetic layer are laminated in a multiple layer can be obtained, thus increasing an MR ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive element and a magnetoresistive head, and more particularly, to a magnetoresistive element which causes a large magnetoresistance change in a low magnetic field, and a high-density magnetic element using the same. The present invention relates to a magnetoresistive head suitable for recording and reproduction.

[0002]

2. Description of the Related Art Conventionally, a magnetoresistive sensor (hereinafter referred to as an MR sensor) using a magnetoresistive element and a magnetoresistive head (hereinafter referred to as an MR head) have been developed. The magnetic material is mainly Ni _0.8 Fe _0.2 permalloy or Ni _0.8 Co
_{A 0.2} alloy film is used. The magnetoresistance change rate (hereinafter referred to as MR ratio) of these magnetoresistance effect materials is about 2.5%. In order to obtain a magnetoresistive element with higher sensitivity, an element having a higher MR ratio is required.

In recent years, [Fe / Cr] and [Co / Ru] artificial lattice films that have antiferromagnetic coupling via a metal non-magnetic thin film of Cr, Ru, or the like are enormous in a strong magnetic field (1 to 10 kOe). It was found to exhibit a magnetoresistance effect (Physical Review Letter 61, paragraph 2472 (1988
64) 2304 (1990) (Physical Review Lette
r Vol.61, p2472, 1988; Vol.64, p2304,1990)).

However, these artificial lattice films require a magnetic field of several kOe to several tens kOe to obtain a large MR change. Therefore, it is not practical for applications such as a magnetic head.

The giant magnetoresistance effect is also obtained in a [Ni-Fe / Cu / Co] artificial lattice film using magnetic thin films Ni-Fe and Co separated by a non-magnetic metal thin film Cu and not magnetically coupled but having different coercive forces. And an MR ratio of about 8% was obtained at a room-temperature applied magnetic field of 0.5 kOe. (Cross-offical physical society off-shear)
59 p. 3061 (1990) (Journal of Physical Society
of Japan Vol.59, p3061, 1990)).

[0006] However, this type of magnetoresistive material requires a magnetic field of about 100 Oe to obtain a large magnetoresistance change. Also, the magnetic resistance of the magnetic field changes asymmetrically from negative to positive, resulting in poor linearity. For this reason, the characteristics are practically difficult to use.

Further, a magnetic thin film Ni-Fe-Co, Co having RKKY-like antiferromagnetic coupling via Cu is used [Ni-Fe-Co / Cu /
The giant magnetoresistance effect was also found in [Co] and [Ni-Fe-Co / Cu] artificial lattice films, and an MR ratio of about 15% was obtained with a room-temperature applied magnetic field of 0.5 kOe (Technical Research Institute of Electronics, Information and Communication Engineers) Report MR91-
9).

However, in the case of this type of magnetoresistive effect material, the magnetoresistance change varies almost linearly from zero magnetic field to the positive direction, and although it exhibits sufficiently practical characteristics for an MR sensor, it still requires a large MR change. Requires a magnetic field of about 50 Oe. For this reason, it is insufficient for use as an MR head that requires operation in a magnetic field of at least 20 Oe or less.

As a device which operates with a small applied magnetic field, a spin valve type device in which Fe-Mn, an antiferromagnetic material, is attached to Ni-Fe / Cu / Ni-Fe has been proposed. S. 93 Paragraph 101 (1991) (Journal o
f Magnetism and MagneticMaterials 93, p101,199
1)). This type of magnetoresistive material has a small operating magnetic field and good linearity, but has a small MR ratio of about 2%. Further, there is a problem of the corrosion resistance of the Fe-Mn film. Furthermore, since the Neel temperature (arrangement temperature) of the Fe-Mn thin film is low, there is a drawback that the temperature dependence of device characteristics is large.

[0010] A spin valve film having a structure of Ni-Fe / Cu / Co-Pt or the like using a hard magnetic material such as Co-Pt instead of using an antiferromagnetic material has also been proposed. In this case, the magnetization of the soft magnetic layer is rotated below the coercive force of the hard magnetic film to create a parallel or anti-parallel state of the magnetization. However, also in this case, it is difficult to improve the characteristics of the soft magnetic layer, and it has not been put to practical use.

As one of means for increasing the MR ratio of the spin valve film, a Cu / Ni-Fe / Cu / Ni / Fe / Cu / Ni / Fe / Cu / Ni / Fe / Cu / Ni / Fe / Cu / Ni / Fe / Cu / Ni / Fe
-Fe / Fe-Mn has also been proposed (USP5422
571). This is an attempt to increase the MR ratio by increasing the mean free path of electrons of a particular spin.

[0012]

The conventional spin-valve MR element has excellent magnetic field sensitivity in both the type using an antiferromagnetic material and the type using a hard magnetic film, but has a low MR ratio. There was a problem. The effect of improving the MR ratio by the low-resistance back layer was not sufficient. This is considered to be because electrons are easily scattered on the surface of the spin valve type MR element because the film thickness is small.

This will be described in more detail as follows.

Originally, the giant magnetoresistance effect was caused by the magnetic layer /
This is due to the spin-dependent scattering of electrons at the interface of the nonmagnetic layer. Therefore, in order to increase the probability of occurrence of this scattering, it is important to reduce the probability of scattering independent of the spin direction and lengthen the mean free path of electrons. In the spin-valve film, the number of laminations of the magnetic layer / non-magnetic layer is small.
Therefore, the thickness of the spin valve film is, for example, about 20 to 50 nm, which is generally smaller than that of a giant magnetoresistance effect film of an antiferromagnetic coupling type. Therefore, the probability that electrons are scattered on the film surface is high, and the mean free path of the electrons is short. This is the main cause of the low MR ratio of the scan film.

Normally, the surface of a thin film has irregularities when viewed at a level of several angstroms, which is the level of the conduction electron wavelength (Fermi wavelength). In this case, the conduction electrons undergo inelastic scattering (diffuse scattering) on the surface. In general,
In the case of diffusion scattering, the spin direction of electrons is not maintained.

The present invention has been made to solve such a problem.

An object of the present invention is to provide a magnetoresistive element and a magnetoresistive head having a high MR ratio.

Another object of the present invention is to provide a spin-valve magnetoresistive element and a magnetoresistive head having a long mean free path of electrons.

Still another object of the present invention is to provide a spin-valve magnetoresistive element and a magnetoresistive effect element having a high probability that electron spin-dependent scattering occurs at the interface between a magnetic layer and a nonmagnetic layer. The purpose is to provide a head.

[0020]

In order to achieve the above-mentioned object, a magnetoresistive element according to the present invention is provided with a metal reflective film on a surface of a spin valve film which is liable to cause reflection scattering while maintaining the spin direction of electrons. It is characterized by being provided.

The metal reflecting film is required to have a smooth surface when viewed at a level of several angstroms. In this case, the conduction electrons cause elastic scattering (specular scattering) on the film surface, the spin direction of the conduction electrons is preserved, and an effect equivalent to the extension of the mean free path appears. Therefore, the MR ratio increases.

As the metal reflection film, a material such as Ag, Au, Bi, Sn, and Pb is preferable. These atoms are different from materials such as Ni, Fe, Cu, and Co films often used in spin valve films, and a smooth surface is easily formed at a level of several angstroms.
In particular, Ag and Au are excellent, and among them, Ag is the most effective. In particular, in the case of Ag and Au, the (111) plane tends to be smoother, and a smooth surface can be easily obtained at a level of several angstroms. Therefore, it is desirable that the (111) plane is substantially parallel to the surface of the substrate.

It is more desirable to insert a nonmagnetic layer such as Cu between the metal reflection film and the spin valve film (magnetic film). This nonmagnetic layer has both an effect as a buffer layer for smoothing the surface of the metal reflection film and an effect to increase spin-dependent scattering at the interface with the magnetic layer.

More desirably, the surface of the magnetic layer on the side where the metal reflection film is provided may be a Co layer. This is because the MR ratio is increased by scattering depending on the spin direction at the interface between the magnetic layer and the nonmagnetic layer (metal reflective film).

More preferably, the entire spin valve film is grown epitaxially on a single crystal substrate.

Preferably, the easy axis of magnetization of the soft magnetic film of the magnetoresistive element is preferably perpendicular to the direction of the signal magnetic field to be detected.

Further, the magnetoresistive head of the present invention provides
The above-described magnetoresistive effect element is further provided with a REET section.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetoresistive element and a magnetoresistive head according to the present invention will be described below with reference to the drawings.

FIG. 1-5 shows an example of a sectional view showing the structure of the magnetoresistance effect element of the present invention. Among them, FIG. 1-3 shows a spin valve film using a hard magnetic film (using two types of magnetic films having different coercive forces). In this case, a magnetic film having a larger coercive force is called a hard magnetic film, and a magnetic film having a smaller coercive force is called a soft magnetic film.

In the magnetoresistive element of the present invention shown in FIG. 1A, a soft magnetic film 3, a non-magnetic film 4, a hard magnetic film 5, and a metal reflective film 6 are formed on a substrate 1 with a base film 2 interposed therebetween. It has a configuration formed sequentially. In the conventional spin valve element, there is no metal reflection film 6, and a protective layer is formed on the surface,
When configuring an MR head, an insulating film or the like is formed as a shield gap material.

Usually, a Ni—Co—Fe alloy is suitable for the soft magnetic film 3 of the spin valve film. The atomic composition ratio of the Ni-Co-Fe film is Ni _x Co _y Fe _z 0.6 ≦ x ≦ 0.9 0 ≦ y ≦ 0.4 0 ≦ z ≦ 0.3 Ni-rich soft magnetic film, or Ni _{x '} Co _{y It} is preferable to use a Co-rich film satisfying 'Fez _' 0 ≦ x ′ ≦ 0.4 0.2 ≦ y ′ ≦ 0.95 0 ≦ z ′ ≦ 0.5. Films with these compositions have low magnetostrictive properties (1) required for sensors and MR heads.
x10 ^-5 ).

As another material of the soft magnetic film 3, Co-M
An amorphous film such as nB, Co-Fe-B, Co-Nb-Zr, or Co-Nb-B may be used.

The thickness of the soft magnetic film 3 is preferably 1 nm or more and 10 nm or less. When the film thickness is large, the MR ratio is reduced due to the shunt effect, but when it is too small, the soft magnetic characteristics are deteriorated. More preferably, the thickness is 2 nm or more and 5 nm or less, and further preferably, 2 nm or more and 3 nm or less.

The hard magnetic film 5 is preferably a ferromagnetic material having a square shape of 0.7 or more, more preferably 0.85 or more. Here, the square shape means a shape represented by Mr / Ms using a saturation magnetic field Ms and a residual magnetization Mr.

If the square shape of the hard magnetic layer is small, perfect parallel and anti-parallel magnetization states cannot be realized with the soft magnetic layer. Therefore, a large square shape is desired.

As the material of the hard magnetic film, Co or Co
Co-based materials such as -Fe alloy and Co-Pt alloy are excellent. Especially
Co or Co-Fe alloy is preferred.

The thickness of the hard magnetic film 5 is preferably 1 nm or more and 10 nm or less. When the film thickness is large, the MR ratio decreases due to the shunt effect,
If the thickness is too small, the magnetic properties deteriorate. More preferably, the thickness is 1 nm or more and 5 nm or less.

As the non-magnetic film 4 between the hard magnetic film 5 and the soft magnetic film 3, there are Cu, Ag, Au, Ru and the like, but Cu is particularly excellent. The thickness of the non-magnetic film 4 is at least 1.5 nm or more, preferably, in order to weaken the interaction between the magnetic layers.
1.8 nm or more is required. When the thickness of the non-magnetic layer 4 is large, the MR ratio is reduced.
Hereinafter, it should be desirably 3 nm or less.

In particular, the hard magnetic film 5
It is also effective to insert another non-magnetic layer having a thickness of 1 nm or less which is effective for reducing the magnetic coupling between the magnetic layer and the soft magnetic film 3.
For example, instead of forming the nonmagnetic layer 4 by a single Cu layer,
It is preferable to use a configuration such as / Ag / Cu, Cu / Ag, or Ag / Cu / Ag. The material of the other nonmagnetic layer to be inserted is preferably Ag, Au or the like. At this time, the thickness of the entire non-magnetic layer 4 is desirably the same as that of the single-layer non-magnetic layer 4 described above. The thickness of the other nonmagnetic layer inserted into the nonmagnetic layer 4 should be at most 1 nm or less, preferably at most 0.4 nm, per layer.

In order to further increase the MR ratio, it is effective to insert an interface magnetic layer at the interface between the magnetic film (soft magnetic film 3 or hard magnetic film 5) and the non-magnetic film 4. If the thickness of the interface magnetic layer is large, the magnetic field sensitivity of the MR ratio decreases. Therefore, the thickness of the interface magnetic layer needs to be 2 nm or less, preferably 1.8 nm or less. In order for this interfacial magnetic layer to work effectively, a film thickness of at least 0.2 nm is required, and a film thickness of 0.8 nm or more is desirable. As a material of the interface magnetic layer, Co or a Co-Fe alloy with a high Co concentration is excellent.

Except when an epitaxial film is formed as described later, that is, when a polycrystalline film is formed, a relatively smooth surface of a glass, Si, Al ₂ O ₃ —TiC substrate or the like is used as the substrate 1. Use a suitable one. When manufacturing an MR head, an Al ₂ O ₃ —TiC substrate is used.

The under film 2 is formed of an upper MR element (soft magnetic film 3).
-It improves the crystallinity of the metal reflective film 6) and improves the MR ratio, and Ta is often used. When an MR head is manufactured, an insulating layer such as SiO ₂ , Al ₂ O ₃ , Ni-F
After the lower shield layer such as e is formed, the Ta underlayer 2 is formed.

In contrast to the basic structure of the spin valve film having the soft magnetic film 3 / non-magnetic film 4 / hard magnetic film 5 described above, in the case of the present invention, the MR ratio is further increased. Therefore, a metal reflection film 6 is added.

If the metal reflective film 6 is not provided, conduction electrons are diffusely reflected on the surface of the hard magnetic film 5, so that information on spin polarization is lost. The giant magnetoresistance effect is
Because it is due to the spin-dependent scattering of conduction electrons,
Loss or loss of spin information at the surface will reduce the MR ratio. Therefore, a large MR ratio could not be obtained with the conventional spin valve film.

On the other hand, in the magnetoresistive element of the present invention provided with the metal reflection film 6, a large amount of conduction electrons are specularly reflected on the surface of the metal reflection film 6, and the spin information is relatively stored. When the electrons are specularly reflected on the surface of the thin film in this manner, the same effect as when the [magnetic layer / non-magnetic layer] is laminated in multiple layers appears, and the MR ratio increases.

In order to cause specular reflection, a smooth interface (surface) at the level of the wavelength of electrons (several angstroms) is required as a thin film surface. The term "smooth surface" as used herein means that it is perfectly satisfactory if the entire surface is completely smooth, but even if there are large irregularities of, for example, several tens of angstroms as a whole, a smooth portion of angstrom units is formed at least in part of the surface. It should just be done. Specifically, a portion in which a super-smooth surface with irregularities of 3 Å or less is formed in a region of 100 × 100 Å or more is required to be at least 10%, preferably at least 20% of the entire surface. To do so, you need to select specific materials.

As the metal reflection film, a material such as Ag, Au, Bi, Sn, and Pb is preferable. These atoms are different from materials such as Ni, Fe, Cu, and Co films often used in Spherical film, and a smooth surface is easily formed on the surface at a level of several angstroms. In particular, Ag and Au are excellent, and among them, Ag is the most effective. In particular, for Ag and Au, the (111) plane is likely to be smoother, and a smooth surface is easily obtained at a level of several angstroms. Therefore, it is desirable that the (111) plane be parallel to the thin film surface. If the metal reflection film is too thick, the MR ratio will decrease due to the shunt effect.
Preferably, the thickness is 3 nm or less. Also, since it is not effective if it is too thin, a film thickness of at least 0.5 nm or more, preferably 1
It is better to be at least nm.

Further, as shown in FIG. 1B, when a non-magnetic film 7 is further inserted between the metal reflection film 6 and the hard magnetic film 5, the MR ratio becomes larger. This is because, when the magnetic film 5 is a Co-based material and a material such as Ag or Au is used for the metal reflection film 6, it is particularly effective to insert a non-magnetic film 7 such as Cu in the middle. . One of the effects of the non-magnetic film 7 is an effect of smoothing the surface of the metal reflection film, and the other is an effect of increasing spin-dependent scattering. This is because the scattering preserving spin occurring at the interface between the magnetic layer and the nonmagnetic layer is larger at the Co / Cu interface than at the Co / Ag interface. From such a viewpoint, when the magnetic layer is made of a material other than Co, Co is added between the non-magnetic film 7 and the magnetic film 5 at the interface between Co and Co-rich Co-Fe alloy. When a magnetic layer is inserted, a film having a larger MR ratio is obtained. The thickness of the interface magnetic layer is the same as the thickness of the interface magnetic layer inserted at the interface between the magnetic film and the nonmagnetic film 4.

The material of the non-magnetic film 7 is the same as that of the non-magnetic film 4. The thickness of the nonmagnetic film 7 is preferably 2 nm or less, and more preferably 1 nm or less. In order to increase the MR ratio, a film thickness of at least 0.5 nm is required.

FIG. 1A shows a case where a soft magnetic film 3, a non-magnetic film 4, a hard magnetic film 5, and a metal reflective film 6 are sequentially formed on a substrate 1 with a base film 2 interposed therebetween. The underlayer 2 is used to increase the MR ratio of the magnetoresistive element, and is used as needed. Also, contrary to FIGS. 1 (a) and 1 (b), FIG.
The present invention is effective even if it is composed of the metal reflection film 6 as shown in FIG.

Further, the metal reflection film 6 may be used on the soft magnetic film 3 side instead of the hard magnetic film 5 side, and may be configured as shown in FIG. Also in this case, the order of lamination of the films is as follows: the metal reflection film 6 / the soft magnetic film 3 / the nonmagnetic film 4 / the hard magnetic film 5 It is good also as composition of.

As shown in FIGS. 1 and 2 (a), the metal reflection film 6 is provided not only on one side of one magnetic layer but also on the other side.
As shown in FIG. 2B, it may be provided on one side of both magnetic layers. In this case, the effect of specular reflection of the electrons is greater than that provided on one side, and the effect of increasing the MR ratio is greater.

FIG. 3 shows an example in which metal reflection films 6 are used on both sides of a dual spin valve film. The so-called dual spin valve film having the structure of hard magnetic film 5 / non-magnetic film 4 / soft magnetic film 3 / non-magnetic film 4 / hard magnetic film 5 is a simple hard magnetic film 5 / non-magnetic film 4 / soft magnetic film. As compared with the spin valve film having the configuration 3, the MR ratio increases because the interface between the magnetic layer and the nonmagnetic layer increases. The metal reflection film 6 is also effective for this film. Even if a metal reflection film is used on one side, there is a certain effect.

When a non-magnetic film is inserted between the metal reflection film 6 and the magnetic film (the soft magnetic film 3 or the hard magnetic film 5), the MR
The fact that the ratio increases is common to the structures shown in FIGS. 1-5.

It should be noted that the above-mentioned effects are exhibited when the magnetoresistive element is a polycrystalline film or a single-crystal film.
The effect is particularly great. This is because when the metal reflection film 6 is an epitaxial film, specular scattering on the surface is promoted.

There are various methods for forming an epitaxial film. Desirably, a substrate of MgO, Si or the like is good. Particularly desirable is a MgO (100) or Si (111) substrate.

When an MgO (100) substrate is used, it is preferable to form a Pt layer as a base layer and further form a Cu layer as a base layer. The thickness of the Pt layer is preferably from 5 nm to 50 nm. After that, for example, an element as shown in FIG. At this time, for example, when the non-magnetic film 7 is made of Cu and the metal reflective film 6 is made of Ag, the difference in lattice constant is large. A good (111) orientation is obtained. This Ag film has a very smooth surface, easily causes specular reflection, and has a large effect of increasing the MR ratio.

In the case of using a Si (111) substrate, an Ag layer is formed directly on the substrate without an underlayer, and then, for example, a non-magnetic film is formed.
Cu, a soft magnetic film Ni-Fe, a non-magnetic film Cu, a hard magnetic film Co, a non-magnetic film Cu, and a metal reflective film Ag are sequentially laminated. At this time,
The thickness of the Ag layer on the substrate needs to be 5 nm or more, and desirably 10 nm or less.

As described above, the case where the metal reflection film is used as the spin valve film using the hard magnetic film has been described. However, the present invention is also effective in the case of the spin valve film using the antiferromagnetic material. . In this case, the magnetization direction of the magnetic film in contact with the antiferromagnetic material is fixed. The magnetization direction of the magnetic film not in contact with the antiferromagnetic material changes due to an external magnetic field, causing a change in resistance. Therefore, in order to increase the magnetic field sensitivity to an external magnetic field, a soft magnetic film is used as the magnetic film that does not contact the antiferromagnetic material. 4 and 5 show this example.

FIG. 4 (a) shows a structure in which a metal reflection film 6, a soft magnetic film 3, a non-magnetic film 4, a magnetic film 8, and an antiferromagnetic film 9 are sequentially formed on a substrate 1 with a base film 2 interposed therebetween. Is shown. In a conventional spin valve film, there is no metal reflection film 6 shown in FIG.
The effect of the metal reflection film 6 to increase the MR ratio of the spin valve film is exactly the same as that of the spin valve film using the hard magnetic film. Therefore, the thickness, material, and the like of the metal reflection film are the same as those described above. It is also effective to insert a non-magnetic film between the metal reflection film 6 and the soft magnetic film 3 as in the case of a spin valve film using a hard magnetic film. FIG. 4
FIG. 4A shows a case where the anti-ferromagnetic material film 6 is formed from the metal reflection film 6. On the contrary, as shown in FIG.
The magnetic film 8 / nonmagnetic film 4 / soft magnetic film 3 / metal reflective film 6 may be formed in this order.

The material of the metal antiferromagnetic film 9 is Fe
-Mn, Ni-Mn, Pd-Mn, Pt-Mn, Ir-Mn, Fe-Ir, and the like. Of these, Fe-Mn has been most often used in conventional spin valve films, but has practical problems from the viewpoint of corrosion resistance and the like.
From this aspect, materials such as Ir-Mn are particularly excellent. Ir _z Mn
_As a suitable composition of the _1-z film, the atomic composition ratio is 0.1 ≦ z ≦
0.5 is better.

As the antiferromagnetic film 9, Ni-O, Co-O, Ni-O / C
Oxides such as oO, Co-Ni-O, and Fe-O can also be used. Among them, Ni-O or α-Fe ₂ O ₃ film is particularly excellent. Such an insulator may be able to achieve a higher MR ratio if its insulating properties are exploited. When used as an MR head, it can also be used as a part of a shield gap material. Further, in the case of an α-Fe ₂ O ₃ film, if a sapphire (11-20) substrate (so-called A surface) is used, it can be formed epitaxially on the substrate. When a Ni—Fe alloy or the like is further formed thereon, it is possible to impart uniaxial anisotropy in the [0001] direction in the film plane, and as a result, a sample having a large MR ratio can be prepared.

FIG. 4 shows a soft magnetic film / non-magnetic film / magnetic film /
Although an example has been described in which a metal reflective film is provided on the soft magnetic film side with respect to the spin valve film having the antiferromagnetic film structure, a metal reflective film may be provided on the antiferromagnetic material side. In this case, it is necessary to use a conductive metal antiferromagnetic material as the antiferromagnetic material, and it is desirable to reduce the film thickness as much as possible. From this viewpoint, as an antiferromagnetic material,
Materials such as Ir-Mn are suitable. It is desirable that the film thickness be 5 nm or more and 10 nm or less.

The material of the magnetic film 8 may be Co, Ni-F
Materials such as e or Ni-Fe-Co are superior.

In the case of a spin valve film using an antiferromagnetic material, as in the case of a spin valve film using a hard magnetic film, the first antiferromagnetic film 9-1 / magnetic film 8 / A dual spin valve structure having a configuration of nonmagnetic film 4 / soft magnetic film 3 / nonmagnetic film 4 / magnetic film 8 / second antiferromagnetic film 9-2 may be used. In this case, as shown in FIG. 5, providing a metal reflection film on at least one of the outside of the antiferromagnetic film has an effect of increasing the MR ratio. At this time, as the antiferromagnetic material (9-2 in FIG. 5) in contact with the metal reflection film, a metal antiferromagnetic material is preferably used, and Ir-Mn or the like is suitable. Conversely, as the antiferromagnetic material not in contact with the metal reflection film, an insulating antiferromagnetic material of an oxide such as Ni-O is suitable. Also in this case, the nonmagnetic layer between the metal reflection film and the antiferromagnetic material has the effect of further increasing the MR ratio.

As a method of forming each layer of the substrate 1 and the magnetic film 8 described above, a sputtering method or a vapor deposition method can be considered. Either method can produce the magnetoresistive element of the present invention. Examples of the sputtering method include a DC sputtering method, an RF sputtering method, and an ion beam sputtering method. Either method can produce the magnetoresistive element of the present invention. In the case of the vapor deposition method,
Ultra-high vacuum deposition is particularly preferred.

A magnetoresistive head can be constructed using the magnetoresistive element of the present invention as described above. FIG. 6 shows an example of the configuration of a hard film bias type MR head as an example of the MR head. In FIG. 6, the MR element section 20 includes upper and lower shield gaps 11 and 14.
It is configured to be sandwiched between. As a shield gap material, an insulating film such as Al ₂ O ₃ or SiO ₂ is used. The shields 10, 15 are further outside the shield gaps 11, 14.
There is. For this, a soft magnetic film such as a Ni-Fe alloy is used. A hard bias section 12 is provided for applying a bias magnetic field by a hard film such as a Co-Pt alloy for controlling the magnetic domain of the MR element. The case of using a hard film has been described as a method of applying a bias, but the same applies to the case of using an antiferromagnetic material such as Fe-Mn. The MR element 20 is shielded by shields 10 and 15 by shield gaps 11 and 14.
Insulated from etc. By passing a current through the lead portion 13, a change in resistance of the MR element portion 20 is read.

In consideration of the high density of hard disk drives in the future, it is necessary to shorten the recording wavelength. For this purpose, it is necessary to reduce the distance d between the shields shown in FIG. For this purpose, as is clear from FIG. 6, it is necessary to reduce the width of the MR element section 20, and it is desirable that the width be at least 20 nm or less.

In the MR element section 20, it is necessary to suppress the generation of Barkhausen noise when the magnetization of the soft magnetic film is reversed. The soft magnetic film 3 shown in FIGS. 1 to 5 is preferably configured such that the axis of easy magnetization is perpendicular to the direction of the signal magnetic field to be detected.

[0070]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A magnetoresistive element and a magnetoresistive head according to the present invention will be described below using specific examples.

Example 1 A MgO (100) single crystal substrate was used as a substrate, and a hard magnetic film was formed by an ultra-high vacuum deposition method.
Were fabricated and their MR characteristics were evaluated. An Ni _0.8 Fe _0.2 (composition indicates an atomic composition ratio) alloy is used as the soft magnetic film 3, Co is used as the hard magnetic film 5, Cu is used as the nonmagnetic film 4, and Ag or Au is used as the metal reflective film. Was. As the evaporation source, an electron beam evaporation source was used for Ni-Fe, Co, and Pt, and a K cell was used for Cu, Ag, and Au.

First, an MgO substrate was kept at 500 ° C. in an ultra-high vacuum evaporation apparatus, and a Pt film was formed epitaxially on a 10 nm substrate as a base layer. Thereafter, the substrate was cooled to room temperature, and a Cu layer was formed to a thickness of 5 nm also as an underlayer. After heating the sample at 200 ° C. for 30 minutes to improve the surface properties, a spin valve film shown in Table 1-1 below was formed at room temperature.

The heat treatment at 200 ° C. after the formation of the Cu underlayer is important for obtaining a smooth surface, and the MR ratio was small even if the spin-valve element was formed on the underlayer where this was not performed. In Table 1-1, MgO / Pt (10 nm) / Cu (5 nm) on the substrate side
Is omitted.

Table 1-1 No. Sample composition MR ratio (%) A1 Ni-Fe (3 nm) / Cu (2.1 nm) / Co (3 nm) 2.8 A2 Ni-Fe (3 nm) / Cu (2.1 nm) / Co (3nm) / Ag (2nm) 3.9 A3 Ni-Fe (3nm) / Cu (2.1nm) / Co (3nm) / Cu (1.2nm) 2.4 A4 Ni-Fe (3nm) / Cu (2.1nm) / Co ( 3nm) / Cu (1.2nm) / Ag (2nm) 5.1 A5 Ni-Fe (3nm) / Cu (2.1nm) / Co (3nm) / Cu (1.2nm) / Pt (2nm) 1.9 A6 Ni-Fe (3nm ) / Cu (2.1nm) / Co (3nm) / Cu (1.2nm) / Au (2nm) 4.7 According to the RHEED (reflection high-energy electron diffraction) pattern observing the film formation, all the samples of A1-A6 above In, Ni-Fe, Cu, C
In the case of o and Pt, the (100) plane grew parallel to the substrate surface (film surface), whereas in the case of Ag and Au films, the (111) plane grew mainly parallel to the film surface.

The surface of the fabricated device was observed using STM. As a result, in Sample A4, 50% or more of the portion having a very smooth surface with irregularities of about 2 Å was observed in a 100 × 100 Å field of view. On the other hand, the surface roughness of the element observed in the same way
A3 was about 7 angstroms, and sample A2 was about 3 angstroms.

The characteristics of the device thus manufactured were evaluated by a DC four-terminal method by applying an external magnetic field of about 500 Oe at room temperature. The evaluation results are shown in Table 1-1. In Table 1-1, in the case of the conventional sample A1 having a simple spin valve structure, the MR ratio is low. In the sample A2 of the embodiment having the configuration shown in FIG. 1A in which the Ag layer as the metal reflection film is provided on the sample A1, the MR ratio is increased by about 1%. On the other hand, even if an attempt is made to substitute the metal reflection layer with a material such as Cu, the MR ratio is lower than that of the sample A1 of the conventional example as shown in the sample A3 of the comparative example.

However, as shown in the structure of FIG. 1B, when an Ag layer is further formed on the Cu layer, the sample A4
As shown in (2), the MR ratio becomes larger than that of the sample A2 of the example. Au has almost the same effect, and the MR ratio increases as shown in sample A6 of the example. In this case, when Pt is used instead of Ag, the MR ratio decreases as shown in Sample A5 of the comparative example.

The case where the soft magnetic film is formed earlier than the hard magnetic film has been described above. The same applies to the case where the hard magnetic film is formed as shown in FIG. 1 (c). The results at this time are shown in Table 1-2. In Table 1-2, similarly to Table 1-1, MgO / Pt (10 nm) / Cu (5 nm) on the substrate side is omitted.

Table 1-2 No. Sample composition MR ratio (%)) A7 Co (3 nm) / Cu (2.1 nm) / Ni-Fe (3 nm) 3 A8 Ag (1 nm) / Co (3 nm) / Cu (2.1 nm) / Ni-Fe (3nm) 4.5 A9 Ag (1nm) / Cu (1nm) / Co (3nm) / Cu (2.1nm) / Ni-Fe (3nm) 5.5 From Table 1-2, conventional spin-valve film As compared with the sample A7, the sample A8 of the embodiment in which the hard magnetic film is provided on the substrate side and
A9 was found to have a large MR ratio.

Although the case where the metal reflection film is provided on the hard magnetic film side has been described above, the same effect can be obtained in the case as shown in FIG. 2A where the metal reflection film is provided on the soft magnetic film side. is there.
Spin valve elements as shown in Table 1-3 were prepared and evaluated in exactly the same manner as in Tables 1-1 and 1-2.

Table 1-3 No. Sample composition MR ratio (%) A10 Co (5 nm) / Cu (2.1 nm) / Ni-Fe (5 nm) 4.0 A11 Co (5 nm) / Cu (2.1 nm) / Ni-Fe (5nm) / Ag (3nm) 5.6 A12 Co (5nm) / Cu (2.1nm) / Ni-Fe (5nm) / Cu (1.2nm) 3.2 A13 Co (5nm) / Cu (2.1nm) / Ni-Fe ( 5 nm) / Cu (1.2 nm) / Ag (3 nm) 7.1 From Table 1-3, it is clear that the samples A11 and A13 of the examples of the present invention have a higher MR ratio than the samples A10 and A12 of the conventional example. .

In the case of Table 1-3, the case of forming from the hard magnetic layer side was described, but the case of forming from the soft magnetic side was prepared and evaluated in exactly the same manner. The results are shown in Table 1-4.

Table 1-4 No. Sample composition MR ratio (%) A14 Ni-Fe (5 nm) / Cu (2.1 nm) / Co (5 nm) 4.2 A15 Ag (1 nm) / Ni-Fe (5 nm) / Cu ( 2.1nm) / Co (5nm) 5.5 A16 Cu (1nm) / Ni-Fe (5nm) / Cu (2.1nm) / Co (5nm) 3.3 A17 Ag (1nm) / Cu (1nm) / Ni-Fe (5nm) / Cu (2.1 nm) / Co (5 nm) 6.2 From Table 1-4, it is clear that the samples A15 and A17 of the example of the present invention have a higher MR ratio than the samples A14 and A16 of the conventional example.

Next, a base film was formed in exactly the same manner as the spin valve film shown in Table 1-1, and then a dual spin valve film of the type shown in FIG. 3 was formed. Table 1-5 shows the composition of the sample and M
The R ratio measurement results are shown.

Table 1-5 No. Sample composition MR ratio (%) A18 Co (3 nm) / Cu (2.1 nm) / Ni-Fe (3 nm) / Cu (2.1 nm) / Co (3 nm) 6.2 A19 Ag (1 nm) ) / Co (3nm) / Cu (2.1nm) / Ni-Fe (3nm) / Cu (2.1nm) / Co (3nm) / Ag (1nm) 8.3 A20 Ag (1nm) / Cu (1nm) / Co (3nm ) / Cu (2.1 nm) / Ni-Fe (3 nm) / Cu (2.1 nm) / Co (3 nm) / Cu (1 nm) / Ag (1 nm) 10.1 As can be seen from Table 1-5, the spin of this example is Samples A19 and A20 of the valve element are samples A18 of the conventional spin valve element.
The MR ratio is large compared to.

(Example 2) Using a Si (111) single crystal substrate as a substrate, a Ni-Fe / Cu / Co spin valve element as shown in FIG. 2 (b) was formed by ultrahigh vacuum evaporation. did. First, the Si substrate is HF
After being immersed in an aqueous solution to remove the natural oxide layer on the surface, the substrate is set in an ultra-high vacuum deposition apparatus. The method for forming the thin film was the same as in Example 1.

First, an Ag layer as a metal reflection film was formed on a Si substrate.
After the epitaxial growth of 7 nm, the substrate is held at about 100 ° C. for 20 minutes. Thereafter, the temperature of the substrate is set to room temperature, and a Cu layer is formed to a thickness of 5 nm as a nonmagnetic film. Thereafter, the substrate was heated to 200 ° C. and held for 20 minutes.

Heating the substrate after the formation of the Ag layer and the formation of the Cu layer is very important for obtaining a smooth surface. Thereafter, the temperature of the substrate was set to room temperature to form a Ni-Fe / Cu / Co / Cu / Ag film.

Table 2 shows the structure of the spin valve film thus manufactured and the MR ratio measured by the same method as in Example 1. In Table 2, Si / Ag (7 nm) / Cu (5 nm) on the substrate side is common and omitted.

Table 2 No. Sample composition MR ratio (%) B1 Ni-Fe (2 nm) / Cu (3 nm) / Co (2 nm) 3.4 B2 Ni-Fe (2 nm) / Cu (3 nm) / Co (2 nm) / Ag (5nm) 5.2 B3 Ni-Fe (2nm) / Cu (3nm) / Co (2nm) / Cu (0.5nm) / Ag (5nm) 6.1 B4 Ni-Fe (2nm) / Cu (3nm) / Co (2nm ) / Cu (0.5 nm) / Au (5 nm) 5.8 In Table 2, sample B1 of the example shows a normal MR ratio because the base film is a metal reflection film. However, sample B2 of the example
As shown in (2), when the metal reflection film layers are provided on both sides of the spin valve film, the MR ratio is further increased. When a Cu layer is inserted as a nonmagnetic layer at the interface between the Co layer of the magnetic layer and the Ag layer of the metal reflection film layer, the MR ratio is further increased (Sample B3). Note that the reflective film layer is on both sides of the spin valve film as shown in Sample B4 of the example,
Different materials may be used between Ag and Au epitaxially grown as a metal reflection film on the Si substrate, or the film thickness may be different.

(Embodiment 3) R using a 6-element target
Using an F magnetron sputtering apparatus, a magnetoresistive element having the configuration shown in FIG. 4A was formed on a water-cooled glass substrate with a 3 nm thick Ta underlayer interposed therebetween. Various elements were manufactured by changing the configuration of the metal reflection film of FIG. 4A in various ways, and the MR ratio was evaluated in the same manner as in Example 1. Table 3 shows the results. (The composition of each alloy is indicated by the atomic composition ratio of the target.) Table 3 No. Sample composition MR ratio (%) C1 Ni _0.8 Co _0.1 Fe _0.1 (5 nm) / Cu (2 nm) / Co (2 nm) / Ir _0.2 Mn _0.8 (8 nm) 4.0 C2 Cu (1 nm) / Ni _0.8 Co _0.1 Fe _0.1 (5 nm) / Cu (2 nm) / Co (2 nm) / Ir _0.2 Mn _0.8 (8 nm) 3.3 C3 Ag (1 nm) / Ni _0.8 Co _0.1 Fe _0.1 (5 nm) / Cu (2 nm) / Co (2 nm) / Ir _0.2 Mn _0.8 (8 nm) 5.2 C4 Ag (1 nm) / Cu (1 nm) / Ni _0.8 Co _0.1 Fe _0.1 (5 nm) / Cu (2 nm) / Co (2nm) / Ir _0.2 Mn _0.8 (8 nm) 6.1 C5 Au (1nm) / Cu (1nm) / Ni _0.8 Co _0.1 Fe _0.1 (5nm) / Cu (2nm) / Co (2nm) / Ir _0.2 Mn _0.8 (8 nm) 5.8 C6 Bi (1 nm) / Cu (1 nm) / Ni _0.8 Co _0.1 Fe _0.1 (5 nm) / Cu (2 nm) / Co (2 nm) / Ir _0.2 Mn _0.8 (8 nm) 5.1 C7 Sn (1 nm) / Cu (1nm) / Ni _0.8 Co _0.1 Fe _0.1 (5nm) / Cu (2nm) / Co (2nm) / Ir _0.2 Mn _0.8 (8nm) 4.8 C8 Pb (1nm) / Cu (1nm) / Ni _0.8 Co _0.1 Fe _0.1 (5 nm) / Cu (2 nm) / Co (2 nm) / Ir _0.2 Mn _0.8 (8 nm) _____ 5.2 In Table 3, the metal reflective film was compared with the spin valve films of the conventional samples C1 and C2. Samples C3-C8 of Examples of the present invention used
Shows a larger MR ratio. As a material of the metal reflection film, Au, Ag, Bi, Sn, Pb, etc. are suitable.
u, Ag, especially Ag is excellent.

Next, the samples C3 and C4 of the present invention and the sample C1 of the conventional example
Using this film as the MR element section 20, an MR head as shown in FIG. 6 was constructed, and the characteristics were evaluated. in this case,
An Al ₂ O ₃ -TiC substrate was used as the substrate, and the lower shield 1 was used.
The upper shield 15 was made of a Ni _0.8 Fe _0.2 alloy, and the lower shield gap 11 and the upper shield gap 14 were made of Al ₂ O ₃ . The hard bias portion 12 is made of a Co-Pt alloy, and the lead portion 13 is made of Au. Also, the direction of the axis of easy magnetization of the magnetic film that has undergone exchange anisotropy from the antiferromagnetic film is such that the direction of easy magnetization of the soft magnetic layer is perpendicular to the direction of the signal magnetic field to be detected. Magnetic film anisotropy was provided so as to be parallel to the direction of the magnetic field.

As a method for this purpose, when forming a magnetic film, a magnetic field was applied by a permanent magnet in a direction in which anisotropy was to be provided in the film surface. When applying an AC signal magnetic field of about 20 Oe to these heads and evaluating the output of both heads,
The outputs of the samples C3 and C4 of the MR head of the present invention are about 30% and 60%, respectively, compared to the head using the sample C1 of the conventional MR element.
The output was high.

(Example 4) R using a six-element target
Using an F magnetron sputtering apparatus, a magnetoresistive element having the configuration shown in FIG. 4B was produced on a water-cooled glass substrate in the same manner as in Example 3. MR is performed in the same manner as in the first embodiment.
The ratio was evaluated. The results are shown in Table 4-1. (The composition of each alloy is indicated by the atomic composition ratio of the target.) Table 4-1 No. Sample composition MR ratio (%) D1 NiO (50 nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) / Cu (2 nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) 4.0 D2 NiO (50 nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) / Cu (2 nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) / Ag (3 nm) 5.5 D3 NiO (50 nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) / Cu (2 nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) / Cu (1 nm) 3.3 D4 NiO (50 nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) / Cu (2nm) / Ni _0.3 Co _0.6 Fe _0.1 (5nm) / Cu (1nm) / Ag (3nm) 6.3 In Table 4-1, compared to the spin valve films of the conventional samples D1 and D3, Samples D2 and D of Examples of the Invention Using Reflective Film
It can be seen that 4 shows a larger MR ratio.

Next, a type spin valve film in which a metal reflection film was provided on the antiferromagnetic film side was prepared in exactly the same manner as the samples in Table 4-1.

Table 4-2 No. Sample composition MR ratio (%) D5 Ni _0.8 Fe _0.2 (5 nm) / Cu (2.5 nm) / Co (2 nm) / Ir _0.2 Mn _0.8 (8 nm) 3.3 D6 Ni _0.8 Fe _0.2 ( 5nm) / Cu (2.5nm) / Co (2nm) / Ir _0.2 Mn _0.8 (8nm) / Ag (1nm) 4.0 D7 Ni _0.8 Fe _0.2 (5nm) / Cu (2.5nm) / Co (2nm) / Ir _0.2 Mn _0.8 (8 nm) / Cu (1 nm) 2.4 D8 Ni _0.8 Fe _0.2 (5 nm) / Cu (2.5 nm) / Co (2 nm) / Ir _0.2 Mn _0.8 (8 nm) / Cu (1 nm) / Ag (1 nm) 4.8 Table 4 -2, the samples D6 and D of the embodiment of the present invention using the metal reflection film were compared with the spin valve films of the samples D5 and D7 of the conventional example.
It can be seen that 8 shows a larger MR ratio.

Next, using the films of the sample D1 of the conventional example and the samples D2 and D4 of the example of the present invention as the MR element section 20, FIG.
The characteristics were evaluated by constructing an MR head as shown in FIG.
In this case, an Al ₂ O ₃ -TiC substrate is used as a substrate, a Ni _0.8 Fe _0.2 alloy is used as a material of a lower shield 10 and an upper shield 15, and a lower shield gap 11 is an insulating film of Ni.
An O film (50 nm) was used in common with the element portion, and Al ₂ O ₃ was used for the upper shield gap 14. The hard bias unit 12
The lead portion 13 was made of Au using a Co-Pt alloy.
Also, the direction of the axis of easy magnetization of the magnetic film that has undergone exchange anisotropy from the antiferromagnetic film is such that the direction of easy magnetization of the soft magnetic layer is perpendicular to the direction of the signal magnetic field to be detected. Magnetic film anisotropy was provided so as to be parallel to the direction of the magnetic field.

As a method for this, when a magnetic film is formed, a magnetic field is applied by a permanent magnet in a direction in which anisotropy is desired to be provided in the film surface. When the output of both heads was evaluated by applying an AC signal magnetic field of about 20 Oe to the heads of these samples D2 and D4, the outputs of the samples D2 and D4 of the MR head of the present invention were compared with the sample D1 of the conventional MR element. The output was about 35% and 50% higher than the heads used, respectively.

(Embodiment 5) R using a 6-element target
Using an F magnetron sputtering apparatus, a magnetoresistive element having the configuration shown in FIG. 5 was formed on a water-cooled glass substrate. The MR ratio was evaluated in the same manner as in Example 1. Table 5 shows the results.
Shown in (The composition of each alloy is indicated by the atomic composition ratio of the target.) Table 5 No. Sample composition MR ratio (%) E1 NiO (50 nm) / Ni _0.8 Fe _0.2 (5 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Ir _0.2 Mn _0.8 (8 nm) 6 E2 NiO (50 nm) / Ni _0.8 Fe _0.2 (5 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 ( 5nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (5nm) / Ir _0.2 Mn _0.8 (8nm) / Ag (3nm) 8.3 E3 NiO (50nm) / Ni _0.8 Fe _0.2 (5nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (5 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Ir _0.2 Mn _0.8 (8 nm) / Cu (1 nm) 4.4 E4 NiO (50 nm) / Ni _0.8 Fe _0.2 (5 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Ir _0.2 Mn _0.8 (8 nm) / Cu (1 nm) / Ag (3 nm) 9.9 In Table 5, the samples E1, Compared to the spin valve film of E3, samples E2 and E4 of the embodiment of the present invention using a metal reflection film
Shows a larger MR ratio.

Next, using the films of the sample E1 of the conventional example and the samples E2 and E4 of the example of the present invention as the MR element section 20, FIG.
The characteristics were evaluated by constructing an MR head as shown in FIG.
In this case, an Al ₂ O ₃ -TiC substrate is used as a substrate, a Ni _0.8 Fe _0.2 alloy is used as a material of a lower shield 10 and an upper shield 15, and a lower shield gap 11 is an insulating film of Ni.
An O film (50 nm) was used in common with the element portion, and Al ₂ O ₃ was used for the upper shield gap 14. The hard bias unit 12
The lead portion 13 was made of Au using a Co-Pt alloy.
Also, the direction of the axis of easy magnetization of the magnetic film that has undergone exchange anisotropy from the antiferromagnetic film is such that the direction of easy magnetization of the soft magnetic layer is perpendicular to the direction of the signal magnetic field to be detected. Magnetic film anisotropy was provided so as to be parallel to the direction of the magnetic field.

As a method for this, when a magnetic film is formed, a magnetic field is applied by a permanent magnet in a direction in which anisotropy is desired to be provided in the film surface. When applying an AC signal magnetic field of about 20 Oe to these heads and evaluating the output of both heads,
The outputs of the samples E2 and E4 of the MR head of the present invention are about 40% and 80%, respectively, compared to the head using the sample E1 of the conventional MR element.
The output was high.

(Example 6) R using a six-element target
Using a F magnetron sputtering apparatus, a magnetoresistive element having the configuration shown in Table 6 was produced on a water-cooled glass substrate.
The MR ratio was evaluated in the same manner as in Example 1. Table 6 shows the results. (The composition of each alloy is indicated by the atomic composition ratio of the target.) Table 6 No. Sample composition MR ratio (%) F1 Ir _0.2 Mn _0.8 (8 nm) / Ni _0.8 Fe _0.2 (5 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Cu (2 nm) / N i _0.8 Fe _0.2 (5 nm) / Ir _0.2 Mn _0.8 (8 nm) 4.5 F2 Ag (3 nm) / Ir _0.2 Mn _0.8 (8 nm) / Ni _0.8 Fe _0.2 (5 nm ) / Cu (2nm) / Ni 0.8 Fe 0.2 (5nm) / C u (2nm) / Ni 0.8 Fe 0.2 (5nm) / Ir 0.2 Mn 0.8 (8nm) / Ag (3nm) 5.5 F3 Cu (1nm) / Ir 0.2 _{Mn 0.8 (8nm) / Ni 0.8} Fe 0.2 (5nm) / Cu (2nm) / Ni 0.8 Fe 0.2 (5nm) / C u (2nm) / Ni 0.8 Fe 0.2 (5nm) / Ir 0.2 Mn 0.8 (8nm) / Cu (1nm) 3.9 F4 Ag (3nm ) / Cu (1nm) / Ir 0.2 Mn 0.8 (8nm) / Ni 0.8 Fe 0.2 (5nm) / Cu (2nm) / Ni 0.8 Fe 0. 2 (5nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (5 nm) / Ir _0.2 Mn _0.8 (8 nm) / Cu (1 nm) / Ag (3 nm) 7.1 In Table 6, the metal reflective film was compared with the spin valve films of the conventional samples F1 and F3. Samples F2 and F4 of Examples of the present invention using
Shows a larger MR ratio.

(Embodiment 7) R using a six-element target
Using an F magnetron sputtering apparatus, a magnetoresistive element having the configuration shown in FIG. 4B was produced on a water-cooled glass substrate in the same manner as in Example 3. MR is performed in the same manner as in the first embodiment.
The ratio was evaluated. Table 7 shows the results. (The composition of each alloy is indicated by the atomic composition ratio of the target.) Table 7 No. Sample composition MR ratio (%) G1 Fe ₂ O ₃ (50 nm) / Co (5 nm) / Cu (2.2 nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) 3.8 G2 Fe ₂ O ₃ (50 nm / Co (5 nm) / Cu (2.2 nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) / Ag (2 nm) 5.4 G3 Fe ₂ O ₃ (50 nm) /Co(5nm)/Cu(2.2nm)/Ni _0.3 Co _0.6 Fe _0.1 (5nm) / Cu (1nm) 3.1 G4 Fe ₂ O ₃ (50nm) / Co (5nm) / Cu (2.2nm) / Ni _0.3 Co _0.6 Fe _0.1 (5 nm) / Cu (1 nm) / Ag (2 nm) 6.2 G5 Fe ₂ O ₃ (50 nm) / Co (5 nm) / Cu (2.2 nm) / Ni _0.3 Co _0.6 Fe _0.1 (2 nm) / Cu (1 nm ) / Ni _0.3 C o _0.6 Fe _0.1 (2 nm) / Cu (1 nm) / Ag (2 nm) 6.0 Table 7 shows the results of using a metal reflective film compared to the spin valve films of the conventional samples G1 and G3. Samples G2, G4,
It can be seen that G5 shows a larger MR ratio. Further, the sample G5 of the example had the MR ratio not much different from the sample G4, but the coercive force of the soft magnetic layer was reduced from about 100e to 50e. As described above, by forming the soft magnetic layer from two or more magnetic films stacked with a non-magnetic film interposed therebetween, the soft magnetic characteristics can be improved and the magnetic field sensitivity can be increased.

Next, using the films of the sample G1 of the conventional example and the samples G2 and G4 of the example of the present invention as the MR element section 20, FIG.
The characteristics were evaluated by constructing an MR head as shown in FIG.
In this case, an Al ₂ O ₃ —TiC substrate is used as a substrate, a Ni _0.8 Fe _0.2 alloy is used as a material of a lower shield 10 and an upper shield 15, and a shield gap 11 is a film Fe ₂ O which is an insulating film.
₃ (50 nm) was shared with the element portion, and Al ₂ O ₃ was used for the upper shield gap 14. The hard bias portion 12 is made of a Co-Pt alloy, and the lead portion 13 is made of Au. Also, the direction of the axis of easy magnetization of the magnetic film that has undergone exchange anisotropy from the antiferromagnetic film is such that the direction of easy magnetization of the soft magnetic layer is perpendicular to the direction of the signal magnetic field to be detected. The magnetic film was given anisotropy so as to be parallel to the direction of the magnetic field.

As a method for this, when a magnetic film is formed, a magnetic field is applied by a permanent magnet in a direction in which anisotropy is desired to be provided within the film surface. When the output of both heads was evaluated by applying an AC signal magnetic field of about 20 Oe to the heads of these samples G2 and G4, the output of the MR head according to G2 and G4 of the sample of the present invention used the conventional sample G1. About each compared to the head
The output was 30% and 45% higher.

(Embodiment 8) R using a six-element target
Using an F magnetron sputtering apparatus, a magnetoresistive element having the configuration shown in FIG. 5 was formed on a water-cooled glass substrate. The MR ratio was evaluated in the same manner as in Example 1. Table 8 shows the results.
Shown in (The composition of each alloy is indicated by the atomic composition ratio of the target.) Table 8 No. Sample composition MR ratio (%) H1 Fe ₂ O ₃ (50 nm) / Ni _0.8 Fe _0.2 (4 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (6 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Ir _0.2 Mn _0.8 (8 nm) 5.5 H2 Fe ₂ O ₃ (50 nm) / Ni _0.8 Fe _0.2 (4 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (6 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Ir _0.2 Mn _0.8 (8 nm) / Ag (3 nm) 7.5 H3 Fe ₂ O ₃ (50 nm) / Ni _0.8 Fe _0.2 (4 nm ) / Cu (2nm) / Ni _0.8 Fe _0.2 (6nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (5nm) / Ir _0.2 Mn _0.8 (8nm) / Cu (1nm) 4.1 H4 Fe ₂ O ₃ (50nm) / Ni _0.8 Fe _0.2 (4 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (6 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Ir _0.2 Mn _0.8 (8 nm) / Cu (1 nm) / Ag (3 nm ) 9.0 H5 Fe ₂ O ₃ (50 nm) / Ni _0.8 Fe _0.2 (4 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (1.5 nm) / Cu (0.8 nm) / N i _0.8 Fe _0.2 (1.5 nm) / Cu (0.8 nm) / Ni _0.8 Fe _0.2 (1.5 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Ir _0.2 Mn _0.8 (8 nm) / Cu (1 nm) / Ag (2 nm) 9.2 Samples H2, H4, and H4 of Examples of the present invention using a metal reflective film as compared with the spin valve films of Samples H1 and H3 of the conventional example.
It can be seen that H5 shows a larger MR ratio. Further, the sample H5 of the example had a smaller MR ratio than H4, but the coercive force of the soft magnetic layer was reduced from about 90e to 30e. As described above, by forming the soft magnetic layer from two or more magnetic films stacked with a non-magnetic film interposed therebetween, the soft magnetic characteristics can be improved and the magnetic field sensitivity can be increased.

Next, using the films of the sample H1 of the conventional example and the samples H2 and H4 of the example of the present invention as the MR element section 20, FIG.
The characteristics were evaluated by constructing an MR head as shown in FIG.
In this case, an Al ₂ O ₃ —TiC substrate is used as a substrate, a Ni _0.8 Fe _0.2 alloy is used as a material of a lower shield 10 and an upper shield 15, and a lower shield gap 11 is an insulating film Fe
₂ O ₃ (50 nm) was shared with the element portion, and Al ₂ O ₃ was used for the upper shield gap 14. Hard bias unit 1
2 was made of a Co-Pt alloy, and the lead portion 13 was made of Au.

The direction of the axis of easy magnetization of the magnetic film that has undergone exchange anisotropy from the antiferromagnetic film is detected so that the direction of easy magnetization of the soft magnetic layer is perpendicular to the direction of the signal magnetic field to be detected. Magnetic film anisotropy was provided so as to be parallel to the direction of the signal magnetic field to be performed.

As a method for this purpose, when forming a magnetic film, a magnetic field was applied by a permanent magnet in a direction in which anisotropy was to be provided in the film plane. When the output of both heads was evaluated by applying an AC signal magnetic field of about 20 Oe to the heads of these samples H2 and H4, the outputs of the MR heads according to the samples H2 and H4 of the present invention were the same as the sample H1 of the conventional MR element. The output was about 30% and 70% higher than the used heads, respectively.

Example 9 Using an sapphire (11-20) substrate, an α-Fe ₂ O ₃ film was formed to a thickness of 100 nm by rf sputtering. Thereafter, the sample was transferred to an ultra-high vacuum
D observation revealed that α-Fe ₂ O ₃ was epitaxially grown in the same direction as the substrate. Then, Co, C in the ultra-high vacuum deposition equipment
u, Ni—Fe, Cu, and Ag films were prepared, and MR characteristics were evaluated in the same manner as in Example 1. Table 9 shows the results.

Table 9 No. Sample composition MR ratio (%) I1 Fe ₂ O ₃ (100 nm) / Co (3 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) 5.1 I2 Fe ₂ O ₃ (100 nm) / Co (3nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (5nm) / Ag (3nm) 7.3 I3 Fe ₂ O ₃ (100nm) / Co (3nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (5nm) / Cu (1 nm) 3.4 I4 Fe ₂ O ₃ (100 nm) / Co (3 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Cu (1 nm) / Ag (3 nm) 9.2 I5 Fe ₂ O ₃ (100 nm) / Co (3nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (5nm) / Co (0.6nm) / Cu (1nm) / Ag (3nm) 11.1 I6 Fe ₂ O ₃ (100nm) / Co (3nm) / Cu (2nm) / Co (0.6nm) / Ni _0.8 Fe _0.2 (5nm) / Co (0.6nm) / Cu (1nm) / Ag (3nm) 12.1 I7 Fe ₂ O ₃ (100nm) / Co (3nm) / Cu ( 2 nm) / Ni _0.8 Fe _0.2 (5 nm) / Co (0.6 nm) / Cu (1 nm) 3.3 Table 9 shows that the present invention using a metal reflective film compared to the spin valve films of the conventional samples I1 and I3. Samples I2 and I4 of Examples
Shows a larger MR ratio. Further, by inserting an interfacial magnetic layer composed of a Co layer at the interface between the nonmagnetic layer and the magnetic layer, the MR ratio was further increased.
It is clearer than 6. On the other hand, in the case of the sample I7 of the comparative example, the MR ratio hardly changes compared to the case of the sample I3. It is considered that this is because the mirror reflection of electrons on the Cu surface is almost nonexistent, and the scattering depending on the spin direction hardly increases at the Co / Cu interface.

In the samples I5 and I6 of the embodiment, the case where the interface magnetic layer is a Co layer has been described.
Almost the same effects can be obtained when an e-alloy is used.

(Embodiment 10) In the same manner as in Embodiment 9, rf
50nm on sapphire (11-20) substrate by sputtering
An α-Fe ₂ O ₃ film having a thickness of 5 was epitaxially grown. Subsequently, Co, Cu, Ni-Fe, Cu, Ag, and Ir-Mn films were produced by the same rf sputtering method, and the MR characteristics were evaluated in the same manner as in Example 1. Table 10 shows the results.

Table 10 No. Sample composition MR ratio (%) J1 Fe ₂ O ₃ (50 nm) / Co (4 nm) / Cu (2 nm) / Ni _0.8 Fe _0.2 (6 nm) / Cu (2 nm) / Co (5 nm) / Ir _0.2 Mn _0.8 (8nm) 5.8 J2 Fe ₂ O ₃ (50nm) / Co (4nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (6nm) / Cu (2nm) / Co (5nm) / Ir _0.2 Mn _0.8 (8nm) / Ag (3nm) 8.2 J3 Fe ₂ O ₃ (50nm) / Co (4nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (6nm) / Cu (2nm) / Co (5nm) / Ir _0.2 Mn _0.8 (8nm) / Cu (1.5nm) 4.9 J4 Fe ₂ O ₃ (50nm) / Co (4nm) / Cu (2nm) / Ni _0.8 Fe _0.2 (6nm) / Cu (2nm) / Co (5nm) / Ir _0.2 Mn _0.8 (8 nm) / Cu (1.5 nm) / Ag (3 nm) 10.3 In Table 10, compared to the spin valve films of the conventional samples J1 and J3, the sample J2 of the embodiment of the present invention using the metal reflective film was used. , J
It can be seen that 4 shows a larger MR ratio.

[0115]

As described above, the spin-valve magnetoresistive element of the present invention can obtain a larger MR ratio than the conventional spin-valve magnetoresistive element. Therefore, when used as a magnetic head, a larger reproduction output can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a cross section of a magnetoresistive effect element according to an embodiment.

FIG. 2 is a schematic diagram of a cross section of another magnetoresistive element according to the embodiment.

FIG. 3 is a schematic diagram of a cross section of another magnetoresistive element according to the embodiment.

FIG. 4 is a schematic view of a cross section of another magnetoresistive element according to the embodiment.

FIG. 5 is a schematic diagram of a cross section of another magnetoresistive element according to the embodiment.

FIG. 6 is a cross-sectional view of an example of the magneto-resistance effect type magnetic head according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Underlayer 3 Soft magnetic film 4 Nonmagnetic film 5 Hard magnetic film 6 Metal reflection film 7 Nonmagnetic film 8 Magnetic film 10 Lower shield 11 Lower shield gap 12 Hard bias part 13 Lead part 14 Upper shield gap 15 Upper shield 20 MR element

Claims (41)

[Claims] At least two magnetic films laminated with a non-magnetic film interposed therebetween, and at least one of the outermost magnetic films of the magnetic film formed in contact with the magnetic film and on the side opposite to the non-magnetic film. And a metal reflection film that easily causes reflection scattering while maintaining the spin direction of electrons. 2. The magnetoresistive element according to claim 1, further comprising a non-magnetic film between said metal reflection film and said magnetic film. 3. The non-magnetic film is made of Cu, and the metal reflection film contains at least one of Ag, Au, Bi, Sn, and Pb as a main component. 3. The magnetoresistive effect element according to item 1. 4. The magnetoresistive device according to claim 2, wherein the magnetic film in contact with the metal reflection film via a non-magnetic film contains Co or Co-rich Co—Fe alloy as a main component. Effect element. 5. The magnetic film comprises at least two layers of a magnetic layer and an interfacial magnetic layer containing Co or a Co-rich Co-Fe alloy as a main component. 3. The semiconductor device according to claim 2, wherein said metal reflection film is in contact with said metal reflection film.
3. The magnetoresistive effect element according to item 1. 6. The magnetic film in contact with the metal reflection film via the non-magnetic film comprises an interface magnetic layer containing Co or a high-concentration Co-Fe alloy as a main component with a soft magnetic layer interposed therebetween. 3. The magnetoresistive element according to claim 2, wherein: 7. The magnetoresistive element according to claim 1, wherein the metal reflection film has a smooth surface. 8. The magnetoresistive element according to claim 7, wherein at least a part of the surface of the metal reflection film is smooth when viewed at a level of angstrom unit. 9. The magnetoresistive element according to claim 8, wherein at least 10% of the surface of the metal reflection film is a smooth surface having irregularities of 3 Å or less. 10. The method according to claim 1, wherein the nonmagnetic film is made of Cu, and the metal reflection film contains at least one of Ag, Au, Bi, Sn, and Pb as a main component. 3. The magnetoresistive effect element according to item 1. 11. A magnetic film directly in contact with said metal reflection film is made of Co.
2. The magnetoresistive element according to claim 1, wherein the main component is a Co-Fe alloy having a high Co concentration. 12. The magnetic film comprises at least two layers of a magnetic layer and an interface magnetic layer containing Co or a Co-rich Co-Fe alloy as a main component. 2. The magnetoresistive element according to claim 1, wherein the element is in contact with the film. 13. The magnetic film, which is in direct contact with the metal reflection film, is made of an interfacial magnetic layer containing Co or a Co-rich Co-Fe alloy as a main component with a soft magnetic layer interposed therebetween. ,
The magnetoresistance effect element according to claim 1. 14. The magnetoresistive element according to claim 1, wherein at least one of the at least two magnetic films has a different coercive force from other magnetic films. 15. The first and the first layers stacked via the non-magnetic film.
And a second magnetic film, an antiferromagnetic material formed on the opposite side of the nonmagnetic film in contact with the first magnetic film, and an antiferromagnetic material formed on the opposite side of the nonmagnetic film in contact with the second magnetic film 2. The magnetoresistive element according to claim 1, further comprising a metal reflective film formed thereon. 16. The magnetoresistive element according to claim 15, further comprising a non-magnetic film between said metal reflection film and said magnetic film. 17. The magnetoresistive element according to claim 15, wherein said antiferromagnetic film is an oxide. 18. The magnetoresistance effect element according to claim 15, wherein said antiferromagnetic film is made of Ni—O. 19. The magnetoresistance effect element according to claim 15, wherein said antiferromagnetic film is α-Fe ₂ O ₃ . 20. The magnetoresistive element according to claim 15, wherein said second magnetic film is composed of two or more magnetic films laminated with a non-magnetic film interposed therebetween. 21. The magnetoresistive element according to claim 15, wherein said antiferromagnetic film is formed epitaxially on a substrate. 22. A structure in which a first magnetic film, said nonmagnetic film, a second magnetic film, an antiferromagnetic film, and said metal reflection film are sequentially formed. 2. The magnetoresistance effect element according to 1. 23. The magnetoresistive element according to claim 22, further comprising a nonmagnetic film between the antiferromagnetic film and the metal reflection film. 24. The magnetoresistive element according to claim 23, wherein said antiferromagnetic film is made of an Ir-Mn alloy. 25. The magnetoresistive element according to claim 22, wherein the antiferromagnetic film is an Ir-Mn alloy. 26. A first antiferromagnetic film, a magnetic film, a nonmagnetic film, a soft magnetic film, a nonmagnetic film, a magnetic film, and a second antiferromagnetic film on a substrate directly or through an underlayer film. 2. The magnetoresistance effect element according to claim 1, wherein a body film and a metal reflection film are sequentially laminated. 27. The magnetoresistive element according to claim 26, further comprising a nonmagnetic film between said second antiferromagnetic film and said metal reflection film. 28. The magnetoresistive element according to claim 27, wherein said second antiferromagnetic film is made of an Ir-Mn alloy. 29. The magnetoresistive element according to claim 26, wherein the first antiferromagnetic film is an oxide. 30. The magnetoresistive element according to claim 26, wherein the first antiferromagnetic film is made of Ni—O. 31. The magnetoresistive element according to claim 26, wherein the soft magnetic film is composed of two or more magnetic films laminated with a non-magnetic film interposed therebetween. 32. The magnetoresistive element according to claim 30, wherein at least one of the first and second antiferromagnetic films is an Ir-Mn alloy. 33. The magnetoresistive element according to claim 26, wherein said first antiferromagnetic film is α-Fe ₂ O ₃ . 34. The method according to claim 3, wherein the first antiferromagnetic film is formed epitaxially on a substrate.
3. The magnetoresistive element according to 3. 35. The magnetoresistance effect element according to claim 26, wherein said second antiferromagnetic film is made of an Ir-Mn alloy. 36. A metal reflective film, a first antiferromagnetic film, a magnetic film, a nonmagnetic film, a soft magnetic film, a nonmagnetic film, a magnetic film, a second 2. The magnetoresistive element according to claim 1, wherein the antiferromagnetic film and the metal reflection film are sequentially laminated. 37. The magnetic device according to claim 36, further comprising a non-magnetic film on at least one of the first and second antiferromagnetic films and the metal reflection film. Resistance effect element. 38. The magnetoresistive element according to claim 1, wherein said nonmagnetic film is formed epitaxially on a substrate. 39. The (1) of the nonmagnetic film perpendicular to the thin film growth direction.
39. The magnetoresistance effect element according to claim 38, wherein the (00) plane is epitaxially grown. 40. The magnetoresistive element according to claim 39, wherein said nonmagnetic film is epitaxially grown on an MgO (100) substrate via a Pt underlayer. 41. At least two magnetic films laminated with a non-magnetic film interposed therebetween, and at least one of the outermost magnetic films of the magnetic film formed in contact with the magnetic film and on the side opposite to the non-magnetic film. A magneto-resistive element having a metal reflective film that easily causes reflection scattering while maintaining the spin direction of electrons; and a lead unit for supplying a current to the magneto-resistive element, and a holding force of the magneto-resistive element. Wherein the axis of easy magnetization of the magnetic film or the magnetic film which is not in contact with the antiferromagnetic material has the smallest perpendicular to the direction of the signal magnetic field to be detected.