JPH09186374A - Magnetoresistive effect element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the soft magnetic characteristics by intersecting the magnetizing direction of two ferromagnetic films substantially perpendicularly in the case of zero signal field and conducting a sense current in the direction of signal field. SOLUTION: A ferromagnetic CoFe film 11, an intermediate nonmagnetic Cu film 12, a ferrormagnetic CoFe film 11, an antiferromagnetic FeMn film 13 and a protective film of Ti 14 are deposited sequentially on a sapphire substrate 10. Two ferromagnetic films 11 serve as a magnetization fixing film for keeping the magnetizing direction substantially even upon application of a signal field and a field detection film for detecting the signal field causing variation of magnetization, respectively. When the signal field is zero, magnetizing direction of two ferromagnetic films 11 intersect perpendicularly to each other thus conducting a sense current in the direction of signal field. This arrangement enhances the soft magnetic characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive effect element used for a magnetic head or the like.

[0002]

2. Description of the Related Art When reading information recorded on a magnetic recording medium, a reading magnetic head having a coil is moved relatively to the recording medium, and the coil is moved by electromagnetic induction generated at that time. In general, a method of detecting a voltage induced in a voltage is used. It is also known to use a magnetoresistive head when reading information [IEEE MA
G-7,150 (1971)]. This magnetoresistive head utilizes the phenomenon that the electric resistance of a certain ferromagnetic material changes according to the strength of an external magnetic field, and is known as a high-sensitivity head for magnetic recording media. . In recent years, the size and capacity of magnetic recording media have been reduced, and the relative speed between the magnetic head for reading and the magnetic recording medium at the time of reading information has become smaller. Expectations for a magnetoresistive head that can be taken out are increasing.

Conventionally, a NiFe alloy (hereinafter abbreviated as permalloy) is used in a portion of a magnetoresistive head in which the resistance is changed by sensing an external magnetic field (hereinafter referred to as an MR element). Permalloy has a maximum magnetoresistance ratio of 3% even though it has good soft magnetic properties.
When used for an MR element for a magnetic recording medium having a small size and a large capacity, the rate of change in magnetoresistance is insufficient. For this reason, a material exhibiting a more sensitive change in magnetoresistance is desired as an MR element material.

In recent years, like Fe / Cr and Co / Cu,
Giant magnetoresistive changes occur in a multi-layer film, a so-called artificial lattice film, in which ferromagnetic films and non-magnetic films are alternately stacked under certain conditions, using antiferromagnetic coupling between adjacent ferromagnetic films. It has been confirmed that it appears, and some have a large magnetoresistance change rate exceeding 100% [Phy
s. Rev. Lett., Vol. 61, 2472 (1988)] [Phys. Rev. Lett., Vol.
64, 2304 (1990)].

On the other hand, even when a ferromagnetic film does not have antiferromagnetic coupling, one of two ferromagnetic films sandwiching a nonmagnetic film by another means without using antiferromagnetic coupling between adjacent ferromagnetic films. Example in which a magnetization is fixed by applying an exchange bias to the other, and the other ferromagnetic film is reversed in magnetization by an external magnetic field, creating a state antiparallel to each other across the non-magnetic film, achieving a large magnetoresistance change Have also been reported. This type is referred to herein as a spin valve structure [Phys. Rev. B., Vol.
45806 (1992)] [J. Appl. Phys., Vol. 69, 4774 (1991)].

Both the artificial lattice film and the film having the spin valve structure have considerably different resistance change characteristics and magnetic characteristics of the laminated film depending on the type of ferromagnetic film. For example, when Co is used in a spin valve structure, for example, Co / Cu / Co /
In FeMn, a large resistance change rate of 8% is generated, but the coercive force is as high as about 20 Oe and the soft magnetic characteristics are not good. Conversely, when permalloy is used, for example, NiFe
For / Cu / NiFe / FeMn, a good value of coercive force of 1 Oe or less is reported, but the rate of change in resistance is not as large as about 4% [J. Al. Phys., Vol. 69, 4774 ( 199
1)]. As described above, the soft magnetic characteristics of the laminated film are good, but the rate of change in resistance is reduced. Therefore, the constituent elements and the film structure of the laminated film satisfying both the soft magnetic characteristics and the rate of change in resistance have not been reported yet.

[0007] The two types of films have the following problems.

In the artificial lattice film, the resistance change rate ΔR / R ignoring the magnetic field range is larger than that of the spin valve type. However, since the antiferromagnetic coupling is large, the saturation magnetic field Hs is large, and soft magnetism is difficult. Furthermore, since the RKKY-like antiferromagnetic coupling is sensitive to the interface structure, stable film formation is difficult, and changes over time tend to occur.

In a film having a spin valve structure, N is added to the ferromagnetic film.
When an iFe film is used, good soft magnetic characteristics can be obtained, but ΔR / R is smaller than that of an artificial lattice film because there are two interfaces between a ferromagnetic film and a nonmagnetic film. In order to increase the number of interfaces, even if a multilayer laminated film is formed by repeatedly laminating a ferromagnetic film, a non-magnetic film, and an anti-ferromagnetic film, an anti-ferromagnetic film having a high resistance exists in the laminated film. Therefore, spin-dependent scattering is suppressed, and eventually, an increase in ΔR / R cannot be expected.

When a signal magnetic field is applied in the hard axis direction of a ferromagnetic film suitable for a magnetic head, the magnetization is rotated by only one side of the ferromagnetic film. Therefore, as shown in FIG. The angle between the magnetization of the ferromagnetic film 2 on the film 1 and the magnetization of the ferromagnetic film 4 on the nonmagnetic film 3 can be changed only up to about 90 °. Note that an angle change of up to 180 ° occurs in the easy axis direction. As a result, ΔR / R decreases to about half in the easy axis direction. Here, even if the exchange bias magnetic field of the ferromagnetic film 2 on the antiferromagnetic film 1 is weakened by some method so that the magnetization rotation of both ferromagnetic films 2 and 4 can be used, Aiming to increase the resistance change rate by reducing the film thickness, ferromagnetic coupling acts between the two ferromagnetic films,
When the signal magnetic field is 0, the magnetization between the ferromagnetic films is directed in the same direction. As a result, even if the magnetization is rotated by the signal magnetic field, the angle change of the magnetization between the two ferromagnetic films is small, and the resistance change is small.

Further, the ferromagnetic coupling between the two ferromagnetic films that works when the thickness of the nonmagnetic film is reduced causes a problem that the magnetic permeability of the ferromagnetic film is deteriorated. Also, a NiFe film having good soft magnetic characteristics has a normal anisotropic magnetoresistance effect, but in a method in which a sense current flows in a direction orthogonal to a signal magnetic field, as shown in FIG. When the magnetizations of the two ferromagnetic films are aligned in the same direction, the anisotropic magnetoresistance effect due to the signal magnetic field and the resistance change due to spin-dependent scattering cancel each other.

[0012]

As a common problem of the artificial lattice film and the spin valve structure film, first, in order to obtain high sensitivity in the magnetic head, it is necessary to increase the supplied current as much as possible. However, in this case, in both of the films, the direction of magnetization of some of the ferromagnetic films is disturbed by the magnetic field generated by the current, so that a highly sensitive resistance change to the magnetic field is prevented. Specifically, in the vicinity of the uppermost layer and the lowermost layer of the laminated film, the current magnetic field is strong, and the magnetization tends to be oriented in the current magnetic field direction.

Second, there is an important problem to be solved when applied to magnetic heads such as Barkhausen noise suppression and operating point bias.

As described above, a magnetoresistive element having an artificial lattice film utilizing spin-dependent scattering or a film having a spin valve structure exhibits good soft magnetic characteristics even when a large current is applied, which is indispensable for high sensitivity. And a large resistance change rate ΔR /
At present, R cannot be indicated.

The present invention has been made in view of the above circumstances, and has a spin-valve structure film or an artificial lattice film having a good soft magnetic property and a sufficient resistance change rate ΔR / R, and has a high sensitivity. An object of the present invention is to provide a magnetoresistive element applicable to a head.

[0016]

SUMMARY OF THE INVENTION The present invention, which has been made to achieve the above objects, relates to a magnetoresistive element having a spin valve structure film as shown in FIG. 1 or an artificial lattice film as shown in FIG. It has a basic structure in which at least a ferromagnetic film, a non-magnetic film, and a ferromagnetic film are sequentially stacked on a substrate. Here, the material of the ferromagnetic film is Co or CoF unless otherwise specified.
e, CoNi, NiFe, sendust, NiFeCo,
Fe ₈ N, and the like. Furthermore, Co _100-x
A ferromagnetic film made of Fe _x (0 <x ≦ 40 atom%) is preferable because it has high ΔR / R and low Hc. The ferromagnetic film preferably has a thickness of 1 to 20 nm. In the present invention, the term “ferromagnetic” includes ferrimagnetism. The material of the non-magnetic film is Mn, Fe, Ni, C.
Nonmagnetic metal such as u, Al, Pd, Pt, Rh, Ru, Ir, Au, or Ag, or CuPd, CuPt, CuA
Examples thereof include u and CuNi alloys. The thickness of the non-magnetic film is preferably 0.5 to 20 nm, and 0.8 to
Particularly preferably, it is 5 nm.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The magnetoresistive effect element of the present invention will be specifically described below.

According to a first aspect of the present invention, there is provided a magnetoresistive element including a laminated film in which at least a ferromagnetic film, a nonmagnetic film, and a ferromagnetic film are sequentially laminated on a substrate,
The two ferromagnetic films are non-bonded, and at least one of the ferromagnetic films contains at least one element selected from the group consisting of Co, Fe, and Ni as a main component, and the close-packed surface thereof is a film. Provided is a magnetoresistive effect element characterized by being oriented in a direction perpendicular to a plane.

In the first invention, that the two ferromagnetic films are non-coupled means that there is substantially no antiferromagnetic exchange coupling between the two ferromagnetic films. Therefore,
In the case of realizing an antiparallel magnetization arrangement state in the two ferromagnetic films, means other than antiferromagnetic coupling between the ferromagnetic films is formed as means for applying a bias magnetic field to the ferromagnetic films. The closest-packed plane orientation is (11) in the case of the fcc phase.
1) means the plane, and in the case of the hcp phase, means the (001) plane.

In the first invention, as a method for orienting the closest surface of the ferromagnetic film in a direction perpendicular to the film surface, the material of the ferromagnetic film may be Pd, Al, Cu, Ta, In, B, N
b, Hf, Mo, W, Re, Ru, Rh, Ga, Zr,
A method of adding at least one element selected from the group consisting of Ir, Au, and Ag (especially, Pd, Cu, Au, and Ag, which hardly decrease the resistance change rate, are preferable); A method using a C surface of a sapphire substrate as a substrate to be formed, Cu,
Materials having an fcc lattice, such as Ni, CuNi, NiFe, Ge, Si, and GaAs; materials having a rhombohedral lattice, such as NiO; Ti, magnetic amorphous metals (CoZrNb, CoH
fTa, etc.), a method of providing a base film made of a material selected from the group consisting of non-magnetic amorphous materials, and MBE.
And the like, and a method of forming a film by an ultra-high vacuum film forming apparatus.

Here, a specific example of the base film will be described in detail. For example, when a ferromagnetic film having an fcc lattice typified by a Co ₉₀ Fe ₁₀ film is used as a Co-based ferromagnetic film, Cu—Ge -Zr, Cu-P, Cu-P-Pd, C
u-Pd-Si, Cu-Si-Zr, Cu-Ti, Cu
Cu-based alloys represented by -Sn, Cu-Ti-Zr, etc.
Au-Dy, Au-Pb-Sb, Au-Pd-Si, A
Au-based alloys such as u-Yb, Al-Cr, Al
-Dy, Al-Ga-Mg, Al-based alloys represented by Al-Si, etc., Pt-based alloys, Pd-based alloys represented by Pd-Si, Pd-Zr, etc., Be-Ti, Be-Ti-Z
r, Be-Zr and other Be-based alloys, Ge-Nb, Ge-P
Ge-based alloys such as d-Se, Ag-based alloys, Rh
Fc of manganese-based alloys, Mn-based alloys, Ir-based alloys, Pb-based alloys, etc.
a metal having a c lattice, an alloy containing a metal having the fcc lattice as a main component, a material having a diamond structure such as Ge, Si, diamond, GaAs, Ga
Materials having a zinc blende structure such as -Al-As, Ga-P, In-P and the like are mentioned as materials having the fcc lattice, and materials containing at least one selected from these as a main component Or a material in which another element is added thereto, or the like. Among the above-mentioned materials, substances other than the single-element metal have a sufficiently high specific resistance as compared with the ferromagnetic film by themselves, and thus have an effect of suppressing the current for the shunt shunt. In addition, various combinations exist for the increase in specific resistance due to the addition of another element to a single element metal, but Cu-based alloys represented by Cu-Ni, Cu-Cr, Cu-Zr, Au-Cr, Fe-Mn, Pt-M
Alloys such as n and Ni-Mn are given as examples.

Examples of the non-magnetic amorphous material include non-magnetic metal materials such as non-magnetic single element metals and alloys and those containing non-metals as additives; amorphous Si such as hydrogenated Si;
Non-magnetic and non-metallic materials such as amorphous carbon such as hydrogenated carbon, glassy carbon, and graphitic carbon are included.

The thickness of the underlayer as described above is not particularly limited, but is preferably 100 nm or less. This is because even if the thickness of the base film is too large, no further effect can be obtained, and conversely, the ratio of the current flowing through the base film in the entire device is large, and as a result, the resistance change rate is reduced. is there. In the first aspect, the underlayer improves the closest plane orientation of the ferromagnetic film. Further, among the above-mentioned non-magnetic amorphous materials, non-magnetic amorphous materials can be grown in layers regardless of the substrate material, and a stable and smooth surface can be obtained. Thus, the surface smoothness of the ferromagnetic film formed thereon and the smoothness of the interface with the nonmagnetic film can be improved. Therefore, it is possible to stably obtain a good resistance change rate. Further, when a non-magnetic material is used as the base film in the first invention, there is no adverse effect on the ferromagnetic film formed thereon.

When the underlayer is formed, the crystal orientation is improved, but the smoothness may be deteriorated and the resistance change rate may be reduced. Therefore, when a material having an fcc lattice or a magnetic amorphous metal is used as a material of the first underlayer for promoting close-packed plane orientation, Ti, Ta, Z
It is preferable that the second underlayer for improving the smoothness made of r, a non-magnetic amorphous material, or the like has a two-layer structure arranged between the first underlayer and the substrate. With this configuration, it is possible to obtain a magnetoresistive element having both good soft magnetic characteristics and a high rate of change in magnetoresistance obtained by improving the crystal orientation in the closest-packed plane. In a two-layer structure,
By using the second underlayer made of a material having the same crystal system as the ferromagnetic film and having a higher specific resistance than the ferromagnetic film material, in addition to the above-described effects, the shunt current component in the current flowing in the element can be improved. Can be reduced. When the base film is used as a laminated structure having two or more layers, it is desirable that the thickness of the laminated structure does not exceed 100 nm.

Examples of the method for producing the underlayer film described above include a two-pole sputtering method using a high-frequency discharge of 13.56 MHz or 100 MHz or more, and an ion source using various ion sources such as an ECR ion source and a Kauffman-type ion source. Various film forming methods such as beam sputtering, vacuum evaporation using an electron beam evaporation source or Knudsen cell, thermal CVD, CVD using various plasmas, MOCVD using organic metal as raw material, and MOMBE. can do. As common to these film forming methods, it is important to manage water and oxygen through evacuation to ultra-high vacuum and ultra-high purity of the source gas. More specifically,
Reduce the content of H ₂ O and O ₂ to ppm or less, preferably pp
It is preferable to reduce to b order.

In the first invention, it is preferable to use a Co-based alloy as the material of the ferromagnetic film. The reason for this is that, in a system containing no Co, the change in resistivity ΔR / R of the obtained magnetoresistance effect element is about 4%, which is lower than that in the case of a Co-based alloy. Due to the large crystal magnetic anisotropy that Co has even when the orientation is realized,
This is because the soft magnetic characteristics may not be improved so much. At this time, in particular, Co _100-x Fe _x (5 ≦ x ≦ 40
Atomic%) is 10% by the fcc phase (111) orientation.
It is preferable because it exhibits the above high ΔR / R and low Hc of less than 80 A / m.

The crystal orientation of the ferromagnetic film is such that the half value width of the rocking curve of the reflection peak on the closest plane (for example, fcc phase (111) plane) in the X-ray diffraction curve is less than 20 °, especially 7 °.
° or less.

In the first aspect of the present invention, the content of the additional element is such that an intermetallic compound which does not impair the ferromagnetism of a ferromagnetic film containing a CoFe alloy or the like as a main component at room temperature and inhibits spin-dependent scattering is formed. It must be within the range that is not performed. For example, when the additive element is Al, Ga, or In, the content is preferably less than 6.5 at%. When the additive element is Nb, Ta, Zr, Hf, B, Mo, or W, the content is preferably less than 10 at%. The additive element is Cu, Pd, Au, Ag, Re, Ru, Rh, Ir
In the case of, the content is preferably less than 40 at%.

As the substrate material, MgO, sapphire, diamond, graphite, silicon, germanium, SiC, BN, SiN, AlN, BeO, Ga
Single crystals represented by As, GaInP, GaAlAs, BP, and the like, polycrystals thereof, sintered bodies containing these as main components, single crystal bodies, polycrystal bodies, and sintered bodies of magnetic or non-magnetic metals The substrate material is selected according to the type of the ferromagnetic film and the material of the underlying film. In particular, it is preferable to use the C-plane of a sapphire substrate that has good lattice matching with a Co-based alloy and has a feature that a smooth surface can be easily obtained. When a single crystal substrate such as a sapphire substrate is used, the thickness of the ferromagnetic film is preferably set to 20 nm or less. This is because the thickness of the ferromagnetic film is 20
This is because if it exceeds nm, the close-packed plane orientation is deteriorated.

Here, in the above-described magnetic film having the closest plane orientation,
When the magnetization direction is slightly inclined from the closest plane, Hc sharply increases. Therefore, if the substrate surface has undulation, the magnetization direction may deviate from within the (111) plane even if the closest-packed plane orientation is realized, and thus Hc may not decrease. For this reason, the surface roughness of the substrate is preferably less than 5 nm.

The magnetoresistive effect element of the first invention is
In addition to the above configuration, a nonmagnetic film and a ferromagnetic film may be alternately stacked a plurality of times.

In the first invention, the densest surface of the ferromagnetic film containing at least one element selected from the group consisting of Co, Fe, and Ni as a main component, for example, the fcc phase (11
1) Good soft magnetic properties can be obtained by orienting the plane in the direction perpendicular to the film surface. This is because an easy axis dependent on the crystal magnetic anisotropy K ₁ does not appear in the fcc phase (111) plane. In addition, by controlling the surface roughness of the substrate on which the ferromagnetic film is formed, the magnetization of the ferromagnetic film can be preserved in the close-packed plane, thereby reducing the coercive force associated with crystal magnetic anisotropy. Can be done. Therefore, better soft magnetic characteristics can be obtained. The coercive force (Hc) is set to 1 by arranging the rocking curve half width to be less than 20 °, preferably 7 ° or less.
Good soft magnetic properties up to 00 A / m, high resistance change rate (ΔR / R) over non-oriented films and other orientations (eg, fcc phase (100) orientation) (eg, ΔR / R for CoFe films)
-10%) and a high-sensitivity magnetoresistive element having both high magnetic permeability.

Here, the normal line of the main crystal orientation plane of the laminated film has a component in the film plane due to the fluctuation of the crystal orientation plane,
The in-plane component of the film has anisotropy, and the normal of a plane defect generated in a crystalline laminated film has fluctuations in the film plane, and this fluctuation causes anisotropy in the film plane. May have. The direction in which such anisotropy is strong is a direction in which ferromagnetic atoms and non-magnetic atoms are likely to be mixed on an atomic plane on which a film is grown. Therefore, it is considered that when a sense current is caused to flow in this direction, that is, in the direction in which the anisotropy due to the in-film component is the largest, the probability of spin-dependent scattering of electrons at the interface increases.

That is, when the crystal orientation plane of the ferromagnetic film of the laminated film is fluctuated or the surface arrangement is introduced to disturb the atomic arrangement, the atomic arrangement in the crystal orientation surface is disturbed. By passing a sense current in the direction of large turbulence, electrons equivalently pass through many interfaces and ferromagnetic films, and the probability of spin-dependent scattering increases. Thus, by setting the direction of the sense current to the direction along the fluctuation direction of the crystal orientation plane of the stacked film,
The magnetoresistance effect element shows a larger resistance change rate.

A second aspect of the present invention is a magnetoresistive effect element comprising a laminated film in which at least a ferromagnetic film, a nonmagnetic film, and a ferromagnetic film are sequentially laminated on a substrate, and at least one of the ferromagnetic films. The film contains at least two elements selected from the group consisting of Co, Fe, and Ni as main components, and P
d, Al, Cu, Ta, In, B, Nb, Hf, Mo,
Provided is a magnetoresistive element having a composition containing at least one element selected from the group consisting of W, Re, Ru, Rh, Ga, Zr, Ir, Au, and Ag.

The magnetoresistive effect element of the second invention may have a structure in which a nonmagnetic film and a ferromagnetic film are alternately laminated a plurality of times in addition to the above structure.

In the second invention, the added content of the additional element is such that an intermetallic compound that does not impair the ferromagnetism of the ferromagnetic film containing CoFe alloy as a main component at room temperature and inhibits spin-dependent scattering is formed. It must be within the range not covered. For example, when the additive element is Al, Ga, or In, the content is preferably less than 6.5 at%. When the additive element is Nb, Ta, Zr, Hf, B, Mo, or W, the content is preferably less than 10 at%. The additive element is Cu, Pd, Au, Ag, Re, Ru, Rh, Ir
In the case of, the content is preferably less than 40 at%.

In the second aspect of the present invention, by adding the above-mentioned additive element, the Hc is up to 100 A / m, the good soft magnetic characteristics and the high sensitivity magnetic resistance having ΔR / R of 5% or more. An effect element can be obtained. In particular, the addition of Al, Ta, Zr, Nb, and Hf significantly improves the soft magnetic properties. In this case, the reason why the soft magnetic property is improved is not clear at present, but it is considered that the effect of reducing the crystal magnetic anisotropy is included in addition to the effect of improving the crystal orientation. Further, Pd, Cu, A
In g and Au, even if they are added in a large amount up to about 40 at%, no intermetallic compound is formed and the lattice constant becomes large, so that the lattice matching with an intermediate non-magnetic film such as Cu is improved. That is, an increase in spin-dependent scattering due to so-called bulk scattering can be expected. Therefore, high ΔR / R can be maintained in addition to the improvement of the soft magnetic characteristics.

A third invention is a laminated film in which a ferromagnetic film of (n + 1) layers and a nonmagnetic film of n layers are alternately formed on a substrate (where n is an integer of 1 to 4). ), The resistivity is 5 adjacent to at least one of the uppermost layer and the lowermost ferromagnetic film of the laminated film.
Provided is a magnetoresistive element in which a ferromagnetic film having a thickness of 0 μΩcm or more is further laminated.

In the third invention, the resistivity is 50 μΩcm.
The high-resistance ferromagnetic film described above may be either a ferromagnetic film or a ferrimagnetic film. The reason why the ferromagnetic film is formed as a laminated film having five or less layers is that when the number of interfaces between the ferromagnetic film and the nonmagnetic film increases, the function of the interface between the high-resistance ferromagnetic film and the ferromagnetic film becomes relatively large. This is because ΔR / R does not improve due to a decrease in the ratio. Therefore, the third invention is suitable for a magnetoresistance effect having a film having a spin valve structure.

By laminating the ferromagnetic film so that the high-resistance ferromagnetic film is in contact with the ferromagnetic film, it is possible to suppress the generation of magnon at the boundary surface. As a result, the probability of spin reversal of electrons due to collision between magnon and electrons can be reduced, thereby increasing the rate of resistance change at room temperature, and realizing a highly sensitive magnetoresistive element. . However, if the resistivity of the high-resistance ferromagnetic film material is less than 50 μΩcm, current mainly flows through the high-resistance ferromagnetic film, and conversely, the resistance change rate decreases. In other words, by using a ferromagnetic film having a resistivity of 50 μΩcm or more, it is possible to prevent a current from being applied to the high-resistance ferromagnetic film, and to suppress a decrease in the magnetoresistance ratio due to the shunt effect.

As the material of the high resistance magnetic film, Ni, F
e, Co, NiFe, NiFeCo, CoFe, Co alloy, etc. to Ti, V, Cr, Mn, Zn, Nb, Tc, H
Those to which elements such as f, Ta, W, and Re are added are exemplified.

In the third invention, the high resistance ferromagnetic film is
It is preferably a high-resistance soft magnetic film. At this time, the adjacent ferromagnetic film and the high-resistance soft magnetic film are integrated, so that the magnetization rotation of the high-resistance soft magnetic film, for example, the amorphous film having good soft magnetic characteristics, The magnetization rotates similarly. Thereby, the soft magnetic characteristics of the ferromagnetic film are improved.

As the high resistance soft magnetic film, a high resistance amorphous film made of CoZrNb or the like, a microcrystalline high resistance soft magnetic film made of FeZrN, CoZrN, or the like, or X of Rh, Nb, Zr, Hf in NiFeX, Ta, Re, I
r, Pd, Pt, Cu, Mo, Mn, W, Ti, Cr,
A film made of a material that is any one element selected from the group consisting of Au and Ag can be used. Among these, amorphous films, CoZrN, NiFeNb
When a film made of a material having an fcc phase is formed adjacent to the lowermost ferromagnetic film, the fcc
This is more preferable because the (111) orientation is promoted.

The thickness of the high resistance ferromagnetic film is preferably 0.5 nm or more. This is because when the film thickness is less than 0.5 nm, the magnetism of the high-resistance ferromagnetic film itself becomes weak, and it becomes difficult to suppress generation of magnon. On the other hand, when the soft magnetic characteristics of the high-resistance ferromagnetic film are inferior to those of the adjacent ferromagnetic films, the thickness of the high-resistance ferromagnetic film is preferably 10 nm or less. This means that the film thickness is 1
If the thickness exceeds 0 nm, the magnetization process of the ferromagnetic film is affected, and it is difficult to obtain soft magnetic characteristics.

A fourth invention is a laminated film (where n is 1 to 4) in which a ferromagnetic film of (n + 1) layers and a first nonmagnetic film of n layers are alternately formed on a substrate. The thickness of at least one of the uppermost and lowermost ferromagnetic films of the laminated film is 5 nm or less, and the thickness is 5 nm or less. A magnetoresistive effect element characterized in that a second non-magnetic film having a resistivity not more than twice that of the ferromagnetic film is further formed adjacent to the above.

In the fourth invention, the material of the second nonmagnetic film preferably has the same crystal structure as the material of the adjacent ferromagnetic film. That is, when the ferromagnetic film is made of a material having an fcc phase, a material having an fcc phase is also preferably used for the first nonmagnetic film. At this time, the difference in lattice constant between the material of the second non-magnetic film and the material of the ferromagnetic film is 5
% Is preferable. In particular, when the second nonmagnetic film is formed adjacent to the lowermost ferromagnetic film, the crystal matching between the ferromagnetic film and the second nonmagnetic film is improved,
It is possible to grow the ferromagnetic film epitaxially, so that scattering of electrons at the interface can be suppressed.

Specifically, the material of the second non-magnetic film is Mn, Fe, Ni, Cu, Al, Pd, Pt, R.
Those containing at least one element selected from the group consisting of h, Ir, Au, and Ag can be used. Further, a base film may be interposed between the substrate and the second non-magnetic film.

In the fourth invention, it is desirable that the crystal grains of the material forming the ferromagnetic film have a large crystal grain size in the film thickness direction so that the crystal growth in each ferromagnetic film is not hindered.
If the number of ferromagnetic films exceeds five, the number of interfaces between the ferromagnetic film and the nonmagnetic film increases, and the spin-dependent scattering effect may substantially disappear. Is 5 layers or less.

In the fourth invention, the thickness of the second nonmagnetic film is preferably in the range of 0.2 to 20 nm. This is because if the thickness of the second non-magnetic film is less than 0.2 nm,
The probability that electrons flowing into the second non-magnetic film undergo inelastic scattering at the interface with the substrate or the like increases, making it difficult to effectively extend the mean free path. Conversely, when the film thickness exceeds 20 nm, This is because no further effect can be obtained, and the current flowing only through the second nonmagnetic film increases, making it difficult to obtain a large resistance change rate.

When the magnetoresistive effect element of the fourth invention is applied to a sensor, the material of the second non-magnetic film should be a plate-like body having a size not more than twice that of the material of the ferromagnetic film such as CoFe alloy. Is required, and it is preferable that the resistivity is smaller than that of the ferromagnetic film. This is because if the resistivity of the second non-magnetic film is significantly higher than the resistivity of the ferromagnetic film, the electrons flowing into the second non-magnetic film are scattered and the effective mean free path can be kept long. This is because an increase in the rate of change in resistance cannot be expected. It is desirable that the material of the second nonmagnetic film has a resistivity equal to or more than １ ／ of the resistivity of the ferromagnetic film. This is because if the resistivity of the material of the second non-magnetic film is less than 1/4 of the resistivity of the ferromagnetic film, the current easily flows only in the second non-magnetic film.

According to the fourth aspect of the invention, the second non-magnetic film is laminated adjacent to at least one of the ferromagnetic films so that the thickness of the ferromagnetic film can be reduced to 5 nm or less. It takes advantage of the fact that the effective mean free path of electrons can be kept for a long time. For example, in a film having a spin valve structure, as the thickness of the ferromagnetic film decreases, the specific resistance increases and the rate of change in resistance decreases. Therefore, by making the ferromagnetic film thinner and stacking a second nonmagnetic film in contact with the thinned ferromagnetic film, electrons are not subjected to inelastic scattering on the surface of the ferromagnetic film and the second nonmagnetic The ferromagnetic film can flow into the film, and the ferromagnetic film can be thinned while keeping the effective mean free path long. In order to obtain the above effect, the number of laminated ferromagnetic films must be five or less.

As described above, in the fourth invention, the second nonmagnetic film is laminated in contact with the ferromagnetic film, so that the thickness of the ferromagnetic film, which usually causes a remarkable decrease in resistance change rate, is 5 nm or less. Even in the case, a magnetoresistive effect element having a large resistance change rate can be obtained. In addition, since the thickness of the ferromagnetic film is reduced to 5 nm or less, even if the ferromagnetic film is processed into a fine shape corresponding to high-density magnetic recording / reproducing with a narrow track width, generation of domain walls due to a demagnetizing field can be suppressed. Therefore, it is possible to prevent the detection sensitivity of the signal magnetic field from lowering and to suppress the occurrence of Barkhausen noise. As a result, a high-sensitivity magnetoresistive element with little noise suitable for reproduction of high-density recording can be realized.

The magnetoresistive element of the fourth invention is
Any of a film having a spin valve structure and an artificial lattice film may be used. However, in the case of a spin-valve magnetoresistive element, it is preferable that a second ferromagnetic film is formed adjacent to a ferromagnetic film whose magnetization is not fixed by an antiferromagnetic film or the like.

A fifth aspect of the present invention is a magnetoresistive effect element comprising a laminated film in which at least a ferromagnetic film, a nonmagnetic film and a ferromagnetic film are sequentially laminated on a substrate. Provided is a magnetoresistive effect element characterized in that a thin film having a larger resistivity and a longer mean free path than that of the ferromagnetic film is further formed adjacent to at least one of the upper and lowermost ferromagnetic films. .

In the fifth invention, examples of the material for the thin film include semimetals such as Bi, Sb and carbon, semiconductors degenerated by high concentration doping, oxide semiconductors such as SnO ₂ and TiO ₂ . The thickness of the thin film is 1 to 50.
It is preferably in the range of nm. This is because if the thickness of the thin film is less than 1 nm, the effect of increasing the mean free path of electrons cannot be sufficiently obtained, and if the thickness exceeds 50 nm, no further effect can be obtained, and only the thin film flows. This is because the current increases and it becomes difficult to obtain a large resistance change rate. Furthermore, if the resistivity of the thin film is smaller than the resistivity of the ferromagnetic film, the current mainly flows through the thin film, and the magnetoresistance effect is conversely reduced, so that the thin film has a higher resistivity than the ferromagnetic film. To have.

In the fifth aspect of the invention, the mean free path means the average distance traveled by the electrons without being scattered by other objects.

In the fifth invention, the thickness of the ferromagnetic film is
In the case of contact with a thin film, the thickness is preferably 5 nm or less for the same reason as in the fourth invention, and the thickness of a ferromagnetic film not in contact with the thin film is preferably in the range of 2 to 20 nm in order to secure the mean free path.

In the fifth aspect of the invention as described above, the effective mean free path of the entire laminated film can be lengthened by laminating thin films having a long mean free path in contact with at least one ferromagnetic film. Are using. For example, the following is known as a physical mechanism of the magnetoresistance effect in the spin-valve type laminated film. That is, in the spin-valve type stacked film, when the directions of magnetization between the two ferromagnetic films are parallel to each other, conduction electrons having either one of a spin parallel to the magnetization and a spin anti-parallel to the magnetization are generated. It is possible to have a long mean free path as a whole and exhibit a low specific resistance value as a whole. On the other hand, when the directions of magnetization between the two ferromagnetic films are antiparallel to each other, no conduction electrons having a long mean free path exist in the entire film, and the specific resistance increases. The magnetoresistance effect in the spin-valve type laminated film is determined by the difference in the length of the mean free path in these two states.

Further, it is known that electrons having spins parallel to the magnetization and electrons having antiparallel spins in the ferromagnetic film have different mean free paths. For the reason, electrons in the spin direction having a long mean free path inside the ferromagnetic film can have a larger magnetoresistive effect in the spin-valve type laminated film if the electron has a longer mean free path. Therefore, in the fifth invention, by laminating a thin film having a mean free path longer than a ferromagnetic film, it is possible to lengthen the effective mean free path of electrons and to increase the magnetoresistance effect. I have. However, if the specific resistance of the thin film is smaller than that of the ferromagnetic film, the current mainly flows through the laminated thin film, and conversely, the magnetoresistance effect decreases. Therefore, the constituent material of the thin film needs to have a long mean free path and a resistivity higher than the resistivity of the ferromagnetic film.

Further, as the thin film having a long mean free path, a material having a large resistivity is used, and the thickness of the ferromagnetic film in contact with the thin film is thinned to increase the specific resistance value of the laminated film as a whole. It will be possible. As a result, a laminated film having a high specific resistance can be obtained, and a large signal voltage can be obtained with a low current density even in a fine pattern. Therefore, problems such as heat generation and migration can be avoided.

The magnetoresistive effect element of the fifth invention is
In addition to the above configuration, a nonmagnetic film and a ferromagnetic film may be alternately stacked a plurality of times.

A sixth aspect of the present invention is a magnetoresistive effect element comprising a laminated film in which at least a ferromagnetic film, a nonmagnetic film, and a ferromagnetic film are sequentially laminated on a substrate, and the laminated film has the highest layer. A magnetoresistive effect element characterized in that a lower ferromagnetic film is made of a CoFe alloy, and an underlying film having an fcc phase having a lattice constant larger than that of a CoFe alloy is further formed adjacent to the ferromagnetic film. provide.

In the sixth invention, the ferromagnetic film formed on the underlying film having the fcc phase having a large lattice constant is Co.
Low Hc is realized when made of Fe alloy,
The improvement in soft magnetic characteristics is remarkable for a ferromagnetic film made of _100-x Fe _x (5 ≦ x ≦ 40 at%). This is Fe
If the concentration is less than 5 at%, the hcp phase is mixed. Conversely, if the Fe concentration exceeds 40 at%, the bcc phase is mixed and lattice mismatch occurs. Other elements that can be added to CoFe include Pd, Al, Cu, Ta, and I.
n, B, Zr, Nb, Hf, Mo, Ni, W, Re, R
u, Ir, Rh, Ga, Au, and Ag. When these elements are added and contained, similar Hc
Reduction is realized.

In the sixth invention, the base film is not limited as long as it is a material having a fcc phase and a lattice constant larger than CoFe, but a material having a resistivity higher than that of the CoFr alloy forming the ferromagnetic film is used. It is preferable to use. Specifically, Cu, Pd, Al, Ni, an alloy containing these as a main component, or a ferromagnetic material having an fcc phase can be used. If the thickness of the underlayer is at least one atomic layer, Hc can be reduced.
Preferably, the thickness is 0 nm or less. However, Cu
When a material having a low resistivity, such as the above, is used, the sense current is easily diverted to the base film, so that the film thickness is particularly preferably 2 nm or less. Preferably, a film for improving smoothness is formed between the substrate and the base film,
Cr, Ta, Zr, T
A film made of i or the like can be used.

In the sixth aspect of the invention, a ferromagnetic film of Co _100-x Fe _x (0 <x <10 is formed on the under film made of a material having an fcc phase and a lattice constant larger than that of the material of the ferromagnetic film.
When the (0 at%) film is formed, an appropriate lattice strain is induced in the CoFe film, and as a result, Hc is significantly reduced, and good soft magnetic characteristics are exhibited. The lattice strain can be easily controlled by adjusting not only the type of the base film but also the thickness of the ferromagnetic film and the thickness of the base film. Therefore, when a non-magnetic film such as a Cu film, a ferromagnetic film having a spin-dependent scattering ability such as a CoFe film, and an antiferromagnetic film are sequentially formed on the ferromagnetic film, a large change in resistance occurs due to a slight signal magnetic field. It becomes a highly sensitive magnetoresistive element. Here, if the resistivity of the base film formed on the substrate is higher than that of the ferromagnetic film, the shunt of the sense current to the base film can be suppressed, and a high resistance change rate is exhibited. Further, when the underlying film does not grow in a layered manner, the smoothness at each interface is degraded and the resistance change rate is reduced. In this case, another underlying film having the function of growing the layered film is provided as described above. A high resistance change rate can be realized by interposing between the base film and the substrate.

The magnetoresistive effect element of the sixth invention is
In addition to the above configuration, a nonmagnetic film and a ferromagnetic film may be alternately stacked a plurality of times.

A seventh aspect of the present invention is a magnetoresistive effect element comprising a laminated film in which at least a ferromagnetic film, a first non-magnetic film, and a ferromagnetic film are sequentially laminated on a substrate, and at least one of them. Adjacent to the main surface of the ferromagnetic film opposite to the first nonmagnetic film, second nonmagnetic films and ferromagnetic films having different thicknesses from the first nonmagnetic film are alternately formed. The magnetoresistive effect element is characterized in that the magnetizations of the respective ferromagnetic films in the unit laminated film composed of these ferromagnetic films and the second ferromagnetic film are ferromagnetically coupled to each other. I will provide a.

In the seventh invention, at least the second non-magnetic film and the ferromagnetic film may be formed adjacent to the ferromagnetic films on both sides formed with the first non-magnetic film interposed therebetween.
One side of the first nonmagnetic film may be a single-layer ferromagnetic film. It is also possible to form a unit laminated film by alternately forming a second non-magnetic film and a ferromagnetic film at least two periods adjacent to the main surface of the ferromagnetic film opposite to the first non-magnetic film. It is. Here, the thickness of the second non-magnetic film in the unit laminated film is preferably 2 nm or less, and the thickness is such that the ferromagnetic films adjacent to each other do not have anti-ferromagnetic coupling like RKKY. Is preferred. This is to keep the magnetization of each ferromagnetic film in the unit laminated film in a ferromagnetically coupled state. For example, when the material of the ferromagnetic film is CoFe and the material of the second nonmagnetic film is Cu, the thickness of the second nonmagnetic film is set so as not to be around 1 nm.

Further, the ferromagnetic film and the second non-magnetic film are grown while maintaining the lattice matching, that is, the ferromagnetic film and the second non-magnetic film are lattice-matched, and extra scattering occurs at the interface between them. It is desirable that there is no Thereby, an increase in resistance can be prevented.

In the seventh invention, the unit laminated film including the ferromagnetic film and the second nonmagnetic film has good soft magnetic characteristics, good lattice matching, and is ferromagnetically coupled. Therefore, the resistance is smaller than that in the antiferromagnetically coupled state, and the number of interfaces between the ferromagnetic film and the nonmagnetic film that causes spin-dependent scattering is large.
Therefore, an increase in the rate of change in resistance due to so-called bulk scattering in the unit laminated film can be expected. Therefore, an artificial lattice film or a film having a spin-valve structure using this unit laminated film as a ferromagnetic film unit has good soft magnetic properties and exhibits a high resistance change rate due to spin-dependent scattering. As a result, a highly sensitive magnetoresistive element can be obtained.

The magnetoresistive element of the seventh invention is
In addition to the above configuration, the first nonmagnetic film and the unit laminated film or the ferromagnetic film may be alternately laminated plural times. Further, the magnetoresistive element of the seventh invention may have any of a spin-valve structure film and an artificial lattice film.

An eighth aspect of the present invention is a magnetoresistive effect element comprising at least a ferromagnetic film, a non-magnetic film and a ferromagnetic film laminated in this order on a substrate. A bias film is formed as a bias magnetic field applying means to the film, the bias film being formed adjacent to or in the vicinity of the laminated film, and the bias magnetic fields in the directions in which the track width direction components are antiparallel to each other in the two ferromagnetic films. Is applied, the magnetizations of the two ferromagnetic films rotate in opposite directions due to a signal magnetic field, thereby providing a magnetoresistive effect element.

In the eighth invention, as a method of applying a bias magnetic field in which the magnetizations of the two ferromagnetic films rotate in opposite directions by the signal magnetic field, a method of forming a bias film adjacent to or close to the laminated film, More specifically, a method using exchange coupling from an antiferromagnetic film, a method using a hard magnetic film, and an exchange bias generated by stacking a new ferromagnetic film on a ferromagnetic film having spin-dependent scattering ability are used. The method and the like, and further, a method utilizing a bias magnetic field generated by a sense current and a magnetostatic coupling (demagnetizing field) generated at the time of fine pattern processing are adopted. However, a bias magnetic field is applied to at least one of the ferromagnetic films by forming the above-described bias film.

Specifically, for example, an antiferromagnetic film is laminated adjacent to two ferromagnetic films, the antiferromagnetic film is used, and the direction of the bias magnetic field is 18 between the adjacent ferromagnetic films.
The ferromagnetic films are magnetized so that they differ by 0 °. The magnetization in this case can be achieved by changing the direction in which a static magnetic field is applied during the film formation of the ferromagnetic film and the antiferromagnetic film by 180 °. Here, the bias magnetic field applied to the adjacent ferromagnetic films is desirably the minimum necessary for forming the ferromagnetic films into a single magnetic domain, for example, 5 kA / m or less. The antiferromagnetic films preferably have different Neel points in order to easily apply bias magnetic fields in different directions to the two ferromagnetic films.

Alternatively, the following method is also available. To apply a bias magnetic field to one ferromagnetic film, an exchange bias magnetic field formed by lamination with an antiferromagnetic film is used. On the other hand, to apply a bias magnetic field to another ferromagnetic film, a new ferromagnetic film is stacked adjacent to the main surface of the antiferromagnetic film on the side opposite to the ferromagnetic film, and the antiferromagnetic film is Utilizes a magnetostatic coupling magnetic field (demagnetizing field) generated when a new ferromagnetic film that has been magnetized and fixed is processed into a fine pattern. The new ferromagnetic film is a ferromagnetic film A (for example, NiFe or CoFe) suitable for applying an exchange bias in order from the side in contact with the antiferromagnetic film.
And another ferromagnetic film B (for example, a Co-based amorphous ferromagnetic film, a nitrided or carbonized microcrystalline ferromagnetic film, etc.) suitable for generating a magnetostatic coupling magnetic field. ) Is desirably a two-layer structure in which ferromagnetic exchange coupling is performed. In this two-layer structure, the magnetostatic property is adjusted by adjusting the Bs and the resistance of the ferromagnetic film B so that the Bs is low and the resistance is high, for example, by adjusting the thickness, the composition, and the manufacturing conditions of the ferromagnetic film B. It is possible to adjust the strength of the coupling bias magnetic field and the so-called shunt bias (operating point bias) generated when a part of the sense current flows through the ferromagnetic film B. It should be noted that the ferromagnetic film has an anisotropic magnetoresistance effect of N
In the case of iFe or the like, it is preferable to flow the sense current in a direction orthogonal to the direction of the signal magnetic field. That is, in the method in which the sense current flows in a direction orthogonal to the signal magnetic field, N
When an iFe film or the like is used, a normal anisotropic magnetoresistance effect that cannot be ignored and a resistance change due to spin-dependent scattering are superimposed, so that ΔR / R increases.

When a bias magnetic field is applied to a ferromagnetic film by using an antiferromagnetic film, it sometimes becomes a problem that the bias magnetic field is too large. It can be reduced by interposing a laminated film of a ferromagnetic film whose anti-ferromagnetic film side is a ferromagnetic film and a non-magnetic film between the ferromagnetic film and the like.

In the eighth aspect of the invention as described above, the magnetization between adjacent ferromagnetic films sharply changes from the antiparallel state to the parallel state due to the signal magnetic field. Further, the bias magnetic field from the antiferromagnetic film or the like necessary to make the magnetization directions antiparallel when the signal magnetic field of both ferromagnetic films is zero is suppressed to the minimum necessary for suppressing Barkhausen noise. . For this reason, when a signal magnetic field is applied in a hard axis direction suitable for a magnetic head (has advantages such as good high-frequency characteristics)
However, the magnetization rotation between the two ferromagnetic films changes the magnetization between the two ferromagnetic films in a relatively low magnetic field range from 0 to 180 °.
Therefore, a large rate of change in resistance, which is almost equal to that in the easy axis direction, is shown in a relatively low magnetic field range. In the eighth invention,
The directions of the bias magnetic fields applied to the two ferromagnetic films do not necessarily have to be antiparallel to each other. In other words, the angle between the magnetization directions of the two ferromagnetic films and the signal magnetic field direction when the signal magnetic field is zero is formed. The angles may not be set to + 90 ° and −90 °, respectively. Specifically, the angles formed by the magnetization directions of both ferromagnetic films and the signal magnetic field when the signal magnetic field is zero are +
It is preferable to set within the range of 30 ° to 60 ° and -30 ° to 60 °. The reason is that the operating point bias becomes unnecessary by inclining the magnetization directions of the two ferromagnetic films when the signal magnetic field is zero from the antiparallel state so that the angle between the ferromagnetic films and the signal magnetic field is within the above-described range. Because.

Further, in the conventional spin valve type magnetoresistive effect element, the resistance change rate exponentially increases as the thickness of the non-magnetic film decreases, so it is desirable to reduce the thickness of the non-magnetic film as much as possible. However, in reality, when the thickness of the non-magnetic film becomes less than 2 nm, the ferromagnetic coupling between the upper and lower ferromagnetic films becomes strong, the antiferromagnetic magnetization arrangement cannot be realized, and the resistance change rate is significantly reduced. There is a problem. However, in the eighth invention in which a bias magnetic field is applied to both ferromagnetic films, the antiferromagnetic magnetization arrangement can be realized by adjusting the antiparallel bias magnetic field intensity even when the thickness of the nonmagnetic film becomes less than 2 nm. A dramatic increase in the rate of resistance change can be expected.

Since a bias magnetic field is applied to the two ferromagnetic films, the magnetic domain walls are eliminated from all the ferromagnetic films, and Barkhausen noise can be suppressed.

The magnetoresistive element of the eighth invention is
In addition to the above configuration, a nonmagnetic film and a ferromagnetic film may be alternately stacked a plurality of times.

A ninth aspect of the present invention is a magnetoresistive effect element comprising a laminated film in which at least a ferromagnetic film, a non-magnetic film, and a ferromagnetic film are sequentially laminated on a substrate. The films serve as a magnetically pinned film whose magnetization direction is substantially maintained even when a signal magnetic field is applied, and a magnetic field detection film whose magnetization changes by the signal magnetic field to detect the signal magnetic field. There is provided a magnetoresistive effect element characterized in that the magnetization directions of the two ferromagnetic films are substantially orthogonal to each other and a sense current is passed in the signal magnetic field direction.

In the ninth invention, as a method of fixing the magnetization of the magnetization fixed film, a method of laminating an antiferromagnetic film so as to exchange-couple with the magnetization fixed film, a method of increasing the Hc of the magnetization fixed film, A method of laminating a ferromagnetic film having a high Hc on the magnetization fixed film can be mentioned. As a method of making the magnetization directions of the magnetization fixed film and the magnetic field detection film orthogonal to each other when the signal magnetic field is zero, a method of giving an easy axis of magnetization of the magnetic field detection film so as to be orthogonal to the magnetization of the magnetization fixed film, There is a method in which a bias film is formed adjacent to or close to the film, and a weak exchange coupling bias of, for example, about 5 kA / m or less is applied in a direction orthogonal to the magnetization of the magnetization fixed film. According to the latter method, even when the magnetic field detection film is made of CoFe having a particularly large bias magnetic field, the magnetization easy axis of the magnetic field detection film is provided in substantially the same direction as the magnetization of the magnetization fixed film,
By applying an exchange coupling bias slightly above the anisotropic magnetic field of CoFe in the in-plane direction perpendicular to the axis of easy magnetization, the magnetic anisotropy of the magnetic field detecting film can be reduced, resulting in a large resistance change in a low magnetic field range. Rate can be obtained.

In the ninth invention, the angle formed by the magnetization of the magnetization pinned film and the magnetization of the signal magnetic field detection film is about 90 when the signal magnetic field is zero.
When the angle is set to °, for example, when the magnetization of the magnetization pinned film is oriented in the direction of the positive signal magnetic field, the angle formed by the magnetization between the adjacent ferromagnetic films becomes ferromagnetic with the positive signal magnetic field, so that the resistance is increased. Conversely, with a negative signal magnetic field, the angle formed by the magnetization between the adjacent ferromagnetic films becomes antiferromagnetic, so that the resistance increases. That is, the operating point bias becomes unnecessary.

Further, when the sense current is passed in the signal magnetic field direction, the magnetization of the magnetic field detection film is inclined by the current magnetic field in the direction orthogonal to the signal magnetic field. Therefore, Barkhausen noise can be suppressed due to the current magnetic field applied to the magnetic field detection film. In this case, since there is a current magnetic field, the magnetic field detecting film does not necessarily need an easy axis of magnetization.

The magnetoresistive effect element of the ninth invention is
In addition to the above configuration, a nonmagnetic film and a ferromagnetic film may be alternately stacked a plurality of times.

A tenth aspect of the present invention is a magnetoresistive effect element comprising a laminated film in which at least a ferromagnetic film, a nonmagnetic film, and a ferromagnetic film are sequentially laminated on a substrate. When the signal magnetic field is zero, the film becomes a fixed magnetic film that retains its magnetization direction substantially even when a signal magnetic field is applied, and a magnetic field detection film that detects the signal magnetic field by changing its magnetization direction due to the signal magnetic field. An angle θ formed by the magnetization directions of the two ferromagnetic films in 30 is not less than 30 ° and not more than 60 °.

In the tenth invention, as a method for fixing the magnetization of the magnetization fixed film, a method utilizing an exchange bias generated by laminating an antiferromagnetic film on the magnetization fixed film and the magnetization are the same as in the ninth invention. There is a method of using a high coercive force film as the ferromagnetic film to be the fixed film. Further, as means for applying a bias magnetic field to the magnetic field detection film, an easy axis of magnetization of the magnetic field detection film,
A bias magnetic field from a hard magnetic film formed adjacent to or close to the magnetic field detection film, a magnetostatic bias generated from a ferromagnetic film formed adjacent to or close to the antiferromagnetic film, a current magnetic field from a sense current, and the like. Available. In order to use the current magnetic field from the sense current, it is necessary to supply the sense current in substantially the same direction as the signal magnetic field. However, from the viewpoint of stably fixing the magnetization in the magnetization fixed film, the sense current is applied in a direction orthogonal to the signal magnetic field so that the current magnetic field from the sense current is applied in almost the same direction as the magnetization direction of the magnetization fixed film. It is desirable to do.

In the tenth aspect of the invention, the angle θ formed by the magnetization fixed film and the magnetic field detection film when the signal magnetic field is zero is 30 to 60.
°, the Barkhausen noise can be removed while eliminating the need for an operating point bias due to the leakage magnetic field from the magnetization fixed film. The angle θ between the magnetization fixed film and the magnetic field detection film as described in the tenth invention is 30 ° or more.
The angle is set to 60 ° because if the angle θ is less than 30 °, the linear response magnetic field range with respect to the signal magnetic field is narrowed, and if it is more than 60 °, Barkhausen noise may not be sufficiently removed.

Here, when the sense current is passed in the direction orthogonal to the signal magnetic field, the direction of the ferromagnetic coupling magnetic field between the two ferromagnetic films and the direction of the current magnetic field are on the same axis. As a result, when a sense current is supplied such that the direction of the current magnetic field is substantially the same as the direction of the ferromagnetic coupling between the adjacent ferromagnetic films that causes a decrease in the magnetic permeability, in this case, the strong magnetization not fixed Since the magnetization direction of the magnetic film rotates in the magnetization direction of the ferromagnetic film to which the magnetization is fixed, the angle formed by the magnetizations of the two ferromagnetic films decreases. As a result, even if a material exhibiting the anisotropic magnetoresistance effect is used as the ferromagnetic film, the anisotropy magnetoresistance effect and the resistance change due to spin-dependent scattering are superimposed, and an increase in sensitivity can be expected. Conversely, if a sense current is applied so that the direction of the ferromagnetic coupling and the direction of the current magnetic field are opposite, in this case, the angle formed by both ferromagnetic films increases. Can be expanded. Therefore, it is preferable to appropriately select the direction in which the sense current is applied according to the material of the ferromagnetic film.

The magnetoresistive effect element according to the tenth aspect of the invention may be one in which a nonmagnetic film and a ferromagnetic film are alternately laminated a plurality of times in addition to the above structure.

An eleventh aspect of the present invention is a magnetoresistive effect element comprising a laminated film in which at least a ferromagnetic film, a nonmagnetic film and a ferromagnetic film are sequentially laminated on a substrate. There is provided a magnetoresistive effect element characterized by comprising, as a bias magnetic field applying means to the film, a bias film having two or more layers laminated adjacent to or close to the laminated film.

In the eleventh invention, the bias film may be formed on the uppermost ferromagnetic film of the laminated film or between the lowermost ferromagnetic film and the substrate, or may be formed on the uppermost layer of the laminated film. Two or more layers may be formed on the ferromagnetic film, or two or more layers may be formed between the lowermost ferromagnetic film and the substrate.

In the eleventh invention, the bias film may be an antiferromagnetic film or a ferromagnetic film,
The exchange coupling magnetic field from the antiferromagnetic film, the exchange coupling magnetic field or the magnetostatic coupling magnetic field from the ferromagnetic film, and the current magnetic field from the sense current are applied to the ferromagnetic film in the laminated film as a bias magnetic field. Is done. Here, when an exchange coupling magnetic field is generated from a ferromagnetic film as a bias film,
Even if a film for reducing the exchange bias is arranged between the ferromagnetic film of the laminated film and the ferromagnetic film as the bias film, the ferromagnetic film as the bias film is formed directly on the ferromagnetic film of the laminated film. You may. However, in the former case, the uniaxial anisotropic magnetic field Hk of the bias film is the uniaxial anisotropic magnetic field Hk of the laminated ferromagnetic film.
k, and the coercive force H of the bias film.
It is preferable that c is larger than the coercive force Hc of the ferromagnetic film of the laminated film.

In the eleventh invention, a bias magnetic field whose magnetization does not substantially move in the signal magnetic field is added to either the uppermost layer or the lowermost ferromagnetic film to form a fixed magnetization film, and the other is formed into a fixed magnetization film. It is preferable to add a bias magnetic field that can detect a signal magnetic field and remove Barkhausen noise to form the magnetic field detection film. At this time, a stack of antiferromagnetic films is suitable for applying a bias magnetic field to the magnetization fixed film. Further, a ferromagnetic film or an antiferromagnetic film is suitably stacked for applying a bias magnetic field to the magnetic field detecting film. Here, the ferromagnetic film as the bias film is made of a single magnetic domain by any method such as a Co-based amorphous film that has been heat-treated in a rotating magnetic field, and has a high-resistance soft magnetic material having a uniform magnetization direction. Film or C heat-treated in static magnetic field
A film having high uniaxial magnetic anisotropy, such as an o- or CoFe-based amorphous film, or a film having a high coercive force is suitable. Also, a ferromagnetic film that becomes a bias film is formed wider than other films,
Even if a hard magnetic film or an antiferromagnetic film is laminated on the edge portion, a high-resistance soft magnetic film having a single magnetic domain can be realized.

In the eleventh aspect of the present invention, at least two layers of bias films are further stacked adjacent to or close to the above-described stacked film so that magnetization can be fixed to a specific ferromagnetic film. It is possible to apply a strong bias magnetic field to the other specific ferromagnetic film with the minimum required bias magnetic field for removing Barkhausen noise. At this time, in the eleventh invention in which two or more bias films are stacked and formed, for example, compared to a case where only the magnetic field detection film is formed wider than other magnetization fixed films and the like and the bias film is stacked at the edge thereof, There is an advantage that a multilayer film including a bias film can be easily manufactured in a short time by collective continuous film formation. This is because it is very difficult to form only the magnetic field detection film widely by removing the edge portions of other magnetization pinned films and the like while leaving only the edge portion of the magnetic field detection film having a thickness of about 1 to 20 nm. based on.

Furthermore, if the bias magnetic fields applied to the ferromagnetic film by the two-layer bias film are made orthogonal to each other,
Similarly to the invention, the angle between the magnetization direction of the magnetization fixed film and the magnetization direction of the magnetic field detection film when the signal magnetic field is zero becomes substantially 90 °, and the operating point bias becomes unnecessary. In addition, Barkhausen noise can be removed by the bias magnetic field applied to the magnetic field detection film,
In addition, the magnitude of the bias magnetic field can be easily controlled by adjusting the magnetic anisotropy and thickness of the bias film or the interface between the stacked film and the bias film. Moreover, when a bias magnetic field is applied in a direction substantially perpendicular to the direction of the easy axis of the ferromagnetic film, the magnetic permeability of the ferromagnetic film made of a Co-based material having a high Hk can be improved.

The eleventh aspect of the present invention comprises, on a substrate, a laminated film in which three layers of ferromagnetic films and two layers of non-magnetic films are alternately formed, and the uppermost and lowermost ferromagnetic films are formed. It can be preferably applied also to a magnetoresistive effect element in which a central ferromagnetic film having a high magnetic permeability serves as a magnetically pinned film and serves as a magnetic field detecting film.

In such a magnetoresistive effect element, the uppermost ferromagnetic film and the lowermost ferromagnetic film have a low magnetic permeability, that is, two or more layers of biases formed adjacent to or close to the laminated film. Since the magnetization is fixed in the film, the change in the magnetization direction with respect to the signal magnetic field is slight. On the other hand, since the central ferromagnetic film has a high magnetic permeability, a slight magnetization causes a large magnetization rotation. As a result, the angle between the magnetization of the uppermost ferromagnetic film and the lowermost ferromagnetic film and the magnetization of the central ferromagnetic film changes sharply by the signal magnetic field. In addition, the number of interfaces that cause spin-dependent scattering is at least twice as large as that of a conventional film having a spin valve structure. Therefore, a large change in resistance can be obtained with a slight magnetic field.

If the magnetization of the central ferromagnetic film is fixed by a bias film such as an antiferromagnetic film to reduce the magnetic permeability,
Since the antiferromagnetic film has a high resistivity, ΔR / R is greatly reduced. However, when the magnetizations of the uppermost and lowermost ferromagnetic films are fixed, the antiferromagnetic film is arranged outside the spin-dependent scattering unit. As a result, the magnetization can be fixed without reducing ΔR / R.

Further, since the ferromagnetic film having a high magnetic permeability exists near the center of the laminated film having the spin valve structure, the current magnetic field from the sense current is weakened, and as a result, the magnetic field detecting film is strong due to the current magnetic field. It is possible to avoid the problem that the magnetization arrangement of the magnetic film is disturbed.

A twelfth aspect of the invention is characterized in that a high coercive force film having a hexagonal C-axis in the film plane and a ferromagnetic film having a coercive force lower than that of the high coercive force film are provided on a substrate. To provide a magnetoresistive effect element.

In the twelfth invention, it is possible to prevent the ordinary high coercive force film from having a high coercive force due to the strong magnetostatic coupling due to the crystal magnetic anisotropy in the direction perpendicular to the film surface. Thus, when the high coercive force film is used as the magnetization fixed film in the film having the spin valve structure, the soft magnetic characteristics of the magnetic field detecting film for detecting the signal magnetic field are not deteriorated. In addition, a parallel state and an anti-parallel state of magnetization can be realized efficiently,
Further, the non-magnetic film thickness in the laminated film can be significantly reduced, so that the resistance change rate can be increased. In addition,
Here, the high coercive force film and the non-magnetic film as the magnetization fixed film may be alternately stacked a plurality of times.

Furthermore, since the single crystal-like high coercive force film has a low electric resistance, even when it is formed as a laminated film with a low coercive force film, the output can be increased without affecting the spin-dependent scattering. Furthermore, since the single crystal-like high coercive force film has high crystal magnetic anisotropy, high magnetic permeability (the magnetization is hard to move)
And the effect of magnetization fixation is large.

Further, in the twelfth invention, the high coercive force film may be used as a bias film for applying a bias magnetic field to the ferromagnetic film. At this time, for example, even when the high coercive force film is used as a bias film for fixing the magnetization of the magnetization fixed film, the soft magnetic characteristic of the magnetic field detection film for detecting the signal magnetic field does not deteriorate. In addition, this high coercivity film can be used as a bias film for Barkhausen noise countermeasure and a bias film that creates an anti-coupling state of magnetization in the absence of a signal magnetic field, and can have both functions at the same time It is. Further, the twelfth invention is not limited to a magnetoresistive element having a laminated film in which a ferromagnetic film and a nonmagnetic film are alternately formed on a substrate, and utilizes an anisotropic magnetoresistance effect of a NiFe alloy or the like. The present invention can also be applied to a magnetoresistive effect element.

Examples of the present invention will be specifically described below.

(Example 1) As a substrate, a sapphire substrate C surface (α-Al ₂ O) was used with a stylus type surface roughness meter having a stylus tip radius of 0.2 μm until the average surface roughness was about 2 nm.
_Three (0001) planes of the substrates were polished to a mirror surface state by the mechanochemical polishing method.

This sapphire substrate was placed in a vacuum chamber and the inside of the vacuum chamber was evacuated to 5 × 10 ⁻⁷ Torr or less. Thereafter, Ar gas is introduced into the vacuum chamber, and the inside of the vacuum chamber is set to about 3 mTorr, and
By performing sputtering in a static magnetic field of A / m, as shown in FIG. 1, a Co ₉₀ Fe ₁₀ film 11 which is a ferromagnetic film and a C which is an intermediate non-magnetic film are formed on a sapphire substrate 10.
The u film 12, the Co ₉₀ Fe ₁₀ film 11 as a ferromagnetic film, the FeMn film 13 as an antiferromagnetic film, and the Ti film 14 as a protective film are sequentially formed to form Ti 5 nm / FeMn 8 nm / Co ₉₀ Fe ₁₀ 8
A laminated film having a spin valve structure of nm / Cu 2.2 nm / Co ₉₀ Fe ₁₀ 8 nm was produced to obtain a magnetoresistive element. Further, Cu leads 15 were formed on the laminated film. In addition,
The composition of the CoFe-based alloy film was Co ₉₀ Fe ₁₀ from the viewpoint of exhibiting a large rate of change in resistance [Journal of the Japan Society of Applied Magnetics, 16 , 313 (1992)] and soft magnetic properties.

Here, as the material of the protective film, in addition to Ti, a non-magnetic material such as Cu, Cr, W, SiN, or TiN can be used. Note that a material other than an oxide is desirably used to prevent oxidation of FeMn. The thickness of the Ti film 14 may not be 5 nm as long as it has a protective effect.
The film thickness should be several tens nm or less in order to prevent a decrease in sensitivity due to a shunt to the Ti film 14 when a sense current flows, and in consideration of having a higher electrical resistivity than the Co ₉₀ Fe ₁₀ film 11. Is desirable.

Co ₉₀ Fe ₁₀ film 1 in contact with the FeMn film 13
No. 1 is magnetization-fixed by FeMn and the other Co ₉₀
The Fe ₁₀ film 11 undergoes magnetization reversal and rotation according to an external magnetic field. The thickness of the Co ₉₀ Fe ₁₀ film 11, which is a ferromagnetic film, is set to 8 nm for both layers, but the thicknesses of the two ferromagnetic films may be the same or different. A ferromagnetic film can be used in principle if its thickness is one atomic layer (0.2 nm) or more.
For practical use of the MR element, 0.5 to 20 nm is appropriate.

The film thickness of the Cu film 12 formed between the two Co ₉₀ Fe ₁₀ films 11 is 2.2 nm in this embodiment, but it may be other than this film thickness, and it is practically 0.5 to 20 nm. Is desirable. As materials other than Cu, Au, Ag,
Ru, Cu alloy, or the like can be used.

The FeMn film 13, which is an antiferromagnetic film, is used for fixing the magnetization of the Co ₉₀ Fe ₁₀ film 11 in direct contact with it. This film thickness can be used as long as it is about 1 nm or more, but is preferably 2 nm to 50 nm from the viewpoint of reliability and practicality.
In addition, other than FeMn, Ni oxide can be used as a material of the antiferromagnetic film. When a Ni oxide is used as a material for the antiferromagnetic film, a good Ni oxide can be obtained by performing sputtering in a mixed gas atmosphere of Ar and oxygen, or by applying ion beam sputtering, dual ion beam sputtering, or the like. An antiferromagnetic film can be formed. Further, since the Ni oxide film can be favorably formed on the sapphire substrate C surface, the spin valve structure is
/ Co ₉₀ Fe ₁₀ 8 nm / Cu 2.2 nm / Co ₉₀ Fe ₁₀ 8 nm
/ Ni oxide can be 50 nm. In this case, N
If the thickness of the i-oxide film is 1 nm or more, a stable bias magnetic field can be applied to the Co ₉₀ Fe ₁₀ film.

The magnetic characteristics, the rate of resistance change, and the crystal structure of the magnetoresistive effect element were examined. The magnetic characteristics were measured with a vibration type magnetometer (VSM) at a maximum applied magnetic field of 1.2 MA / m, and the resistance change rate was measured in a static magnetic field by a four-terminal resistance measurement method. The crystal structure was measured by θ-2θ scan and rocking curve X-ray diffraction. In VSM and X-ray diffraction, the resistance change rate was measured for a film patterned into an 8 mm square with a metal mask and for a film patterned in a 1 mm × 8 mm stripe shape with a metal mask. The resistance change of the magnetoresistive element in a magnetic field was measured by a four-terminal method.

The measurement results of the magnetoresistive effect element are shown in FIG. As can be seen from FIG. 2, when an external magnetic field was applied in the easy axis direction, the maximum resistance change rate was about 10%. The coercive force of this magnetoresistive element was 160 A / m or less. As described above, this magnetoresistive element has about 1
At a weak magnetic field of 60 A / m, a large resistance change of about 10% was obtained, and it was found that good soft magnetic characteristics and a high resistance change rate were obtained. When an external magnetic field was applied in the direction of the hard axis, the rate of change in resistance was about 4%, but the coercive force was 80 A / m, and the soft magnetic properties were extremely good.

Magnetization curves of this magnetoresistive effect element are shown in FIGS. 3 (A) and 3 (B). As can be seen from FIG. 3A, the coercive force in the easy axis direction is about 160 A /
m, the coercive force in the hard axis direction is about 80 A / m. As can be seen from FIG. 3B, an exchange bias of about 5.3 KA / m is applied to the Co ₉₀ Fe ₁₀ film in contact with FeMn in the direction of the easy axis.

Further, the crystal structure of this magnetoresistive effect element showed strong fcc phase (111) plane orientation (closest plane orientation).

Ti was formed on the thermally oxidized Si substrate in the same manner as above.
/ FeMn / CoFe / Cu / CoFe films were formed.
As a result of the evaluation in the same manner as described above, the closest-packed surface peak of X-ray diffraction was reduced to 1/10 or less as compared with the above case, Hc was 3000 A / m in the easy axis direction, and the magnetoresistance effect element was used. Is a high value that is difficult to apply, and the resistance change rate is 8% or less, which is smaller than that of the (111) orientation film.

Next, a Ti / FeMn / CoFe / Cu / CoFe film was formed on the MgO (100) substrate in the same manner as above. As a result of evaluating this in the same manner as described above, only the high intensity (100) peak
That is, good (100) orientation was shown. At this time, H
c is 1200 A / m in the easy axis direction, which is a high value that is difficult to apply to the magnetoresistance effect element, and the resistance change rate is 8% or less, which is smaller than that of the (111) orientation film.

From the above, it can be seen that when the (111) orientation is realized, low Hc and a high resistance change rate can be realized.

Next, Ti using a Co film as a ferromagnetic film was used.
5 nm / FeMn8 nm / Co8 nm / Cu2.2 nm / Co8
A spin-valve magnetoresistive element having a thickness of nm was fabricated on a sapphire C-plane substrate, and the magnetic properties and the rate of change of resistance were measured in the same manner as above. And the coercive force is 800 A / m
There was about. In the thermal oxidation Si substrate, ΔR / R = 7
%, Hc = 2000 A / m.

From these results, C was selected as the material for the ferromagnetic film.
Even if o is used, a low Hc and a high ΔR / R can be obtained, but the use of an alloy obtained by adding Fe to Co as the material of the ferromagnetic film is more preferable because soft magnetic characteristics are easily generated.

Furthermore, Ti5nm / FeMn8nm / Co
_100-x Fe _x 8 nm / Cu 2.2 nm / Co _100-x Fe _x 8
A spin-valve magnetoresistive element composed of a nm / sapphire C-plane or a glass substrate was manufactured by changing the Fe concentration x (atomic%) of the Co _100-x Fe _x ferromagnetic film. The relationship between ΔR / R and Hc obtained as a result is shown in Table 1 below. As can be seen from Table 1, 5 ≦ x ≦ 4 on the sapphire C surface.
It is clear that a significant Hc reduction and an increase in ΔR / R are realized in the range of 0.

[0123]

[Table 1]

(Example 2) A Cu base film having a thickness of 10 nm was formed on the C surface of a sapphire substrate, on a glass substrate (# 0211 manufactured by Corning Incorporated), and on the (111) surface of a Si substrate.
Further thereon, C was formed under the film forming conditions similar to those of Example 1.
An o ₉₀ Fe ₁₀ film was formed. The Cu underlayer can be formed by a bias sputtering method, an ion-assisted ion beam sputtering method, an evaporation method, or the like. This Co ₉₀
The coercive force (Hc) of the Fe ₁₀ film was measured. Further, a Co ₉₀ Fe ₁₀ film was formed on each of the above-mentioned substrates with a Cu base film interposed therebetween with various thicknesses, and the coercive force (Hc) of the Co ₉₀ Fe ₁₀ film was measured. FIG. 6 shows the result. further,
Co ₉₀ Fe ₁₀ films of various thicknesses were formed on the substrate in the same manner as above without forming a Cu underlayer, and the coercive force (Hc) thereof was measured. FIG. 7 shows the result.

As can be seen from FIGS. 6 and 7, in any of the substrates, the case where the Cu underlayer is formed (FIG. 6) shows a lower Hc than the case where there is no Cu underlayer. In addition, regardless of the presence or absence of the Cu underlayer, Hc is lower in the order of the C surface of the sapphire substrate, the (111) surface of the Si substrate, and the glass substrate, which indicates that the Hc is good. Especially,
When a Co ₉₀ Fe ₁₀ film having a thickness of 8 nm was formed on the C surface of the sapphire substrate via a Cu underlayer, a low Hc of 80 A / m or less was exhibited. Note that Co ₉₀ Fe ₁₀ having a Cu underlayer
The Hc of the film showed a tendency to increase slightly as the thickness of the Co ₉₀ Fe ₁₀ film increased. On the other hand, C without a Cu underlayer
The Hc of the o ₉₀ Fe ₁₀ film firstly decreased with an increase in the film thickness, and tended to increase as the film thickness increased. For example, when the thickness of the Co ₉₀ Fe ₁₀ film is about 8 nm, the minimum value of Hc was 160 A / m or less.

As described above, it is understood that good soft magnetic characteristics can be obtained by forming the base film between the ferromagnetic films when they are formed on the substrate.

On the C plane of the sapphire substrate or Si
It has been found that good soft magnetic properties can be obtained by using a CuNi alloy film as a base film when a Co ₉₀ Fe ₁₀ film or a Co film is formed on a substrate. When a Co ₉₀ Fe ₁₀ film or a Co film is formed on a glass substrate or a ceramic substrate, Ge, S
It was found that the use of the i or Ti film promoted the close-packed plane orientation, and as a result, obtained a good soft magnetic property.

Further, by using a material having a higher resistance than the Co ₉₀ Fe ₁₀ film or the Co film for the base film, the shunt of the MR sense current can be prevented. For example, the Ni oxide film described in the first embodiment has a high resistance and is an antiferromagnetic film that can be epitaxially grown on the C-plane of the sapphire substrate. Can be. FIG. 8 shows a magnetoresistive element having a spin valve structure using the Ni oxide film 26.

Example 3 The influence of the plane orientation of the sapphire substrate on the coercive force of the Co ₉₀ Fe ₁₀ film was examined. In this embodiment, the C-plane and the R-plane ((1 of the α-Al ₂ O ₃ substrate are
012) surface).

A Co ₉₀ Fe ₁₀ film having a film thickness of 10 nm was formed on each of the C surface and the R surface of the sapphire substrate. FIGS. 9A and 9B show differences in crystal orientation depending on the plane orientation. As can be seen from FIG. 9A, a good fcc (111) orientation can be realized on the C plane, and as a result, the coercive force becomes 1
A CoFe alloy film having a good soft magnetic property of 60 A / m or less was formed. On the other hand, as can be seen from FIG. 9 (B), on the R plane, in addition to the peak of fcc (111), f
The peak of cc (200) is detected, and fcc (111)
The orientation is not very good. Therefore, the coercive force is several hundred A /
m or more, and good soft magnetic properties could not be obtained.

In FIG. 9 (A), fc is present near 2θ = 43.5 ° in addition to the peak of sapphire which is the substrate on the C plane.
Only the peak corresponding to the c-phase (111) plane (some hcp
Phase (001) orientation). The higher the peak intensity, the lower the Co ₉₀ Fe ₁₀ film showed a lower coercive force. On the other hand, in FIG. 9B, a peak corresponding to the fcc phase (200) plane appears near 2θ = 52.6 ° in addition to the sapphire peak and the fcc phase (111) plane peak on the R plane. The presence of the (100) plane orientation of the fcc phase means that the easy axis of crystal magnetic anisotropy appears in the plane, which causes an increase in coercive force.

Next, a rocking curve was measured for the peak corresponding to the (111) plane (closest plane) of the Co ₉₀ Fe ₁₀ film on the C plane of this sapphire substrate. FIG. 10 shows the rocking curve. As can be seen from FIG. 10, a very strong orientation having a half-width of about 3 ° with a peak near θ = 21.8 ° can be confirmed. The peak of the sapphire substrate overlaps with this rocking curve,
Good crystal orientation of the Co ₉₀ Fe ₁₀ film can be confirmed.

[0133] Next, FIG. 11 shows the coercive force of the Co ₉₀ Fe ₁₀ film, the correlation between the half width of the rocking curve of the peak corresponding to Co ₉₀ Fe ₁₀ film (111) plane (close-packed plane) . As can be seen from FIG. 11, Co ₉₀ on the glass substrate.
When the Fe ₁₀ film was formed, the (111) peak was often weak, the rocking curve half width was 20 ° or more, and Hc was 3000 A / m or more. When the Ar pressure and the substrate temperature are optimized and the half width of the rocking curve becomes about 15 °, Hc decreases to about 1000 A / m. When a film made of a material obtained by adding about 1% of Al to Co ₉₀ Fe ₁₀ is formed on a glass substrate, the half width is 8 °.
Hc becomes about 350 A / m. Also,
By forming a Co ₉₀ Fe ₁₀ film on the C-plane of the sapphire substrate, the half-value width is further reduced to about 3 ° and Hc
Is about 160 A / m. Therefore, the closest surface (C
It can be confirmed that as the half width of the rocking curve of the peak corresponding to the case of the o ₉₀ Fe ₁₀ film ((111) plane) decreases to less than 20 °, the coercive force tends to sharply decrease. For example, when the half width of the rocking curve is 7 ° or less,
It can be seen that the coercive force approaches a good value of 160 A / m. That is, according to the close-packed plane orientation of the Co ₉₀ Fe ₁₀ film is getting stronger, the coercive force of the Co ₉₀ Fe ₁₀ film is reduced. Thus, it can be seen that good soft magnetic properties have a strong correlation with the degree of orientation of the ferromagnetic film.

As a method for strengthening the close-packed plane orientation of the Co ₉₀ Fe ₁₀ film, as described above, firstly, a method of adding various additive elements described later, secondly, a method of selecting a substrate material / orientation, There are several methods such as a method of forming an underlayer film between the substrate and the Co ₉₀ Fe ₁₀ film in 3 and a method of forming a film by an ultra high vacuum film forming apparatus such as MBE. In the second method, when the C surface of a sapphire substrate is used as the substrate, the surface is polished with mechanochemical polish, float polish, ion polish, or the like to reduce the average surface roughness (Ra) of the substrate to 2 nm or less. As a result, it was found that the Co ₉₀ Fe ₁₀ film formed thereon exhibited better soft magnetic characteristics. However, when the average surface roughness was 5 nm or more, the coercive force of the Co ₉₀ Fe ₁₀ film was 1000 A / m or more.

Example 4 In Example 3, Co ₉₀ F
It was found that the coercive force of the single-layer film of the e ₁₀ film was decreased by increasing the close-packed plane orientation by the first and second methods. Next, it will be confirmed whether or not the same can be said for the stacked film including the Co ₉₀ Fe ₁₀ film.

Al-containing Co ₉₀ Fe ₁₀ 10 on a glass substrate
A laminated film of nm / Cu 5 nm / Al-containing Co ₉₀ Fe ₁₀ 10 nm was formed under the same film forming conditions as in Example 1. Co in this case
The relationship between the ₉₀ Fe ₁₀ Al element addition amount in the film and the Co ₉₀ Fe ₁₀ film coercivity is shown in Figure 12. As can be seen from FIG.
It can be seen that the coercive force can be reduced also in the laminated film by adding the Al element. In the second to fourth methods described in the second embodiment, the Co ₉₀
The orientation of the closest-packed surface of the Fe ₁₀ film could be strengthened.

Next, FIG. 13 shows the close-packed surface peak intensity dependence of the coercive force of the Co ₉₀ Fe ₁₀ film in the laminated film. FIG.
As can be seen from the graph, as in the case of the single-layer film, the coercive force decreases as the peak density on the closest surface increases, but it can be confirmed. In the case of the above structure, the peak intensity is as low as 10 ² (au), and the coercive force is about 10 ³ A / m. In this case, by using a film made of a material obtained by adding about 1 atomic% of Al to Co ₉₀ Fe _10, the coercive force was reduced to about several hundreds A / m. Further, by replacing the glass substrate with the C-plane of the sapphire substrate, a peak intensity of 10 ³ (au) or more and a good coercive force of 100 A / m or less were obtained. The half width at this time was 7 ° or less.

Example 5 The coercive force was examined by adding an additive element other than Al to Co ₉₀ Fe ₁₀ . In this case, as additive elements, Ta, Pd, Zr, Hf, Mo, Ti, Nb, C
A decrease in coercive force was also observed when u, Rh, Re, In, B, Ru, Ir, and W were used. In addition, a decrease in coercive force was confirmed even when a combination of these elements, for example, Ta and Pd, Nb and Pd, and Zr and Nb were added. As an example, FIG. 14 shows the relationship between the added amount of Ta and the coercive force in the structure of a laminated film of Ta-containing Co ₉₀ Fe ₁₀ 10 nm / Cu ₅ nm / Ta-containing Co ₉₀ Fe ₁₀ 10 nm. As can be seen from FIG. 14, even in this case, it can be confirmed that the coercive force was lowered by the addition of the Ta element.

(Example 6) The above is an example in which the (111) high orientation is realized for the CoFe film.
Not only the film but also a CoFeNi film, a CoNi film, or the like has the same effect. The examples are shown in Table 2 below. Table 2 shows a structure similar to that shown in FIG. 1 (contact with FeMn film) prepared by using (1) composition of ferromagnetic film, (2) type of substrate, and (3) base film between substrate and spin valve film as parameters. The figure shows the rocking curve half-value width Δθ ₅₀ of the (111) peak, Hc in the easy axis direction, and ΔR / R in the spin valve film having the CoFe film (the side remains the CoFe film). For comparison, Table 2 also shows the results when a spin valve film of a ferromagnetic film having the same composition as in Table 2 was formed on a glass substrate without a base film.

[0140]

[Table 2]

As can be seen from Table 2, not only the CoFe film but also the CoFeNi film and the CoNi film are formed on the sapphire C-plane substrate or Ti, compared to the direct film formation on the glass substrate.
By using a base film made of Si, Ge, etc., Δθ
It is possible to obtain a good (111) orientation film with ₅₀ <7 °,
As a result, Hc decreases, and a high resistance change rate can be realized.

However, the (111) highly-oriented (M 1 nm thickness / Cu
1nm thick) ₁₆ were manufactured superlattice (M: Co ₂₀ N
i ₈₀ , Co ₂₀ Fe ₁₅ Ni ₆₅ ) and ΔR / R showed extremely small values of 2% or less, and the high saturation magnetic field peculiar to RKKY antiferromagnetic coupling disappeared. It can be seen that the RKKY-like antiferromagnetic coupling cannot be obtained with the (111) orientation, so that the resistance change rate has decreased. Therefore, a type that does not use anti-ferromagnetic coupling like RKKY as well as a spin valve film (a so-called uncoupled artificial lattice film using the difference in coercive force (The 14th Annual Meeting of the Japan Society of Applied Magnetics, 1990, (P. 177)), it is easy to achieve both a high rate of change in resistance and good soft magnetism when (111) high orientation is realized.

In addition to this, it was confirmed that the same effect can be obtained by replacing the ferromagnetic film in contact with FeMn with a film having the same composition as the lower magnetic film.

Example 7 On glass substrate (without base film)
Ti5nm / FeMn8nm / CoFe8nm / Cu2.2
A spin valve film (nm / ferromagnetic film 8 nm) was formed under the same conditions as in Example 1. At this time, Table 3 below shows the relationship between the nonmagnetic addition element added to the lower ferromagnetic film, the resistance change rate in the easy axis direction, and Hc.

[0145]

[Table 3]

As can be seen from Table 3, Hc was lower than that of the film formed on the glass substrate and containing no nonmagnetic element. The addition of Al, Ta or the like markedly reduced the Hc, but the addition of a large amount significantly reduced the resistance change rate. A
1 is less than 6.5 atomic%, Ta is less than 10 atomic%,
It can be seen that both the resistance change rate of 5% or more, which is higher than that of the spin valve film made of NiFe, and the low Hc can be achieved at the same time. Note that C
When Al or Ta was added to oFe, the close-packed plane peak intensity increased in X-ray diffraction. On the other hand, Cu, Au, A
Although g, Pd and the like are not as remarkable in the Hc reducing effect as Al or Ta, no decrease in the resistance change rate is observed even when added in a large amount of 10 atomic% or less. Cu, Au, A to CoFe
The addition of g, Pd, etc. also increased the peak intensity of the close-packed plane in X-ray diffraction. It is considered that the decrease in Hc is due to the improvement in crystal orientation described above, since the peak intensity of the closest-packed surface in X-ray diffraction was improved by the added element. In addition to this, the decrease in crystal magnetic anisotropy due to the additional element may also be due to the decrease in Hc.

Furthermore, the corrosion resistance of each single-layer ferromagnetic film (thickness: 100 nm) was examined by leaving it in a constant temperature and humidity bath at 65 ° C. and 95% RH for 100 hours. However, the CoFe film containing no non-magnetic element, the Co ₂₀ Ni ₈₀ film, the Co ₂₀ Fe ₁₅ Ni ₆₅ film, the film containing 6.5 atomic% of Al, and the film containing 6 atomic% of Ta are discolored. It was observed. That is, the addition of Pd exerts an effect of improving corrosion resistance. When only Pd is added, H
Although the decrease of c is not so remarkable, if Pd is added together with, for example, Cu, the soft magnetic property can be further improved while maintaining a high resistance change rate and corrosion resistance. Further, when a sapphire C-plane substrate, an amorphous metal base film, or a base film with an fcc lattice is used, Hc is 80 A / m even when only Pd is added.
To less than 40 at% of Pd
A high resistance change rate of 10% was exhibited in the concentration range. However, when the same noble metal was added with Pt, which is expected to be effective in improving corrosion resistance, Hc increased more than the film without Pt added. Therefore, addition of Pt is not preferable from the viewpoint of soft magnetic characteristics.

(Embodiment 8) After the surface of a thermally oxidized Si substrate having _a surface roughness R _a = 2 nm or less was cleaned by SH (mixed solution of sulfuric acid and hydrogen peroxide) treatment, this substrate was placed in a vacuum apparatus. It was then evacuated to below 1 × 10 ⁻⁹ Torr. Water and oxygen in the vacuum equipment were controlled by mass spectrometer and dew point meter. After the above procedure is completed, ultra-high-purity Ar gas is introduced into the apparatus and the degree of vacuum in the apparatus is set to 1 × 10 ⁻⁴ Torr.
Then, a microwave discharge of 2.45 GHz was generated inside the ECR ion source and sputtering was performed using an accelerated ion beam. As shown in FIG.
Amorphous Si is used as the first base film 151 on the substrate 150.
The film was formed with a film thickness of 5 nm. After that, a Cu—Ni alloy having a film thickness of 2 nm was continuously formed on the first base film 151 as the second base film 152 while maintaining the vacuum.

C is formed on the surface as the first ferromagnetic film 153.
The second ferromagnetic film 1 has an o ₉₀ Fe ₁₀ alloy film having a thickness of 8 nm, a nonmagnetic film 154 having a Cu—Ni alloy film having a thickness of 2.2 nm.
A spin valve structure is formed by sequentially forming a Co ₉₀ Fe ₁₀ alloy film with a thickness of 8 nm as 55, an Fe—Mn alloy film with a thickness of 8 nm as an antiferromagnetic film 156, and a Ti film with a thickness of 5 nm as a protective film 157. Was produced. All of the above thin films were formed by ion beam sputtering. Furthermore, a spin-valve magnetoresistive element 159 was obtained by forming Cu electrodes 158a and 158b on the laminated film.

C in the ferromagnetic films 153 and 155
The composition of the oFe-based alloy film was Co ₉₀ Fe ₁₀ from the viewpoint of a large rate of change in resistance (Journal of the Japan Society of Applied Magnetics: 16.313 (1992)) and soft magnetic properties.

The crystallinity, the magnetic characteristics and the resistance change rate of the spin valve type magnetoresistive effect element thus obtained were measured. The half-width by X-ray diffraction of the CoFe alloy film was 1 °, and the soft magnetic characteristics The coercive force, which is one of the physical properties indicating the above, was 0.1 Oe. The magnetoresistance ratio measured using this element showed a high value of about 10%.

For comparison, a substrate subjected to the same treatment was placed in a vacuum apparatus, exhausted to 1 × 10 ⁻⁷ Torr or less, and then ordinary Ar gas was introduced to 2 × 10 ⁻³ Torr. A Cu film was directly formed as a base film without forming an amorphous Si film on the surface of the substrate, and a laminated film having the same spin valve structure as that of Example 8 was formed on the surface. further,
A Cu electrode was formed on this laminated film to obtain a magnetoresistive element. This laminated film was formed by a normal two-pole sputtering method excited at 13.56 MHz.

When the crystallinity, magnetic properties and resistance change rate of this magnetoresistive effect element were measured, the half-width of the CoFe alloy film by X-ray diffraction was 7 °, which is one of the physical properties exhibiting soft magnetic properties. The coercive force was 1.5 Oe. Also,
The magnetoresistance ratio measured using this device was about 5%.

Example 9 After cleaning the surface of a sapphire substrate having _a surface roughness R _a = 2 nm or less, the substrate was placed in a vacuum apparatus and evacuated to 1 × 10 ⁻⁹ Torr or less. Water and oxygen in the vacuum equipment were controlled by mass spectrometer and dew point meter. After the above procedure was completed, an amorphous CuTi film having a thickness of 3 nm was formed as a first base film by an ultra-high vacuum evaporation method using an electron beam evaporation source. After that, the pumping frequency is 100MHz continuously while maintaining the vacuum.
A FeMn alloy film having a film thickness of 2 nm was formed as a second base film by using the ultra-high vacuum RF sputtering.

Next, on the above-mentioned base film, Ti5 nm / FeM
n8 nm / (Co ₈₁ Fe ₉ ) Pd ₁₀ 8 nm / Cu 2.2 nm /
(Co ₈₁ Fe ₉ ) Pd ₁₀ A layered film having a spin valve structure having a thickness of 8 nm is formed by using ultrahigh vacuum RF sputtering at an excitation frequency of 100 MHz. A valve-type magnetoresistive element was manufactured.

The crystallinity, magnetic characteristics and resistance change rate of the spin valve type magnetoresistive element thus obtained were measured in the same manner as in Example 8. The half width of the CoFe film by X-ray diffraction was 1.5. The coercive force, which is one of the physical properties exhibiting soft magnetic characteristics, was 1 Oe. Further, the magnetoresistance ratio measured using the same element showed a high value of about 12%.

(Embodiment 10) As shown in FIG. 16, a high resistance amorphous layer 3 made of CoZrNb or the like is formed on a supporting substrate 30.
1 is formed, and a ferromagnetic film 32 made of a CoFe alloy or the like, a non-magnetic film 33 made of Cu or the like, a ferromagnetic film 32, and an exchange bias layer 34 made of FeMn or the like are formed thereon at about 4 kA.
Sequentially formed in a static magnetic field of / m, and leads 35 were formed on the exchange bias layer 34 to manufacture a magnetoresistive effect element. Each layer was formed by a four-element sputtering apparatus under the film forming conditions shown in Table 4 below.

[0158]

[Table 4]

The magnetic characteristics of this magnetoresistive element were investigated,
17 and 18 show the MH curve (magnetization-magnetic field curve). 17 shows the MH curve in the easy axis direction, and FIG. 18 shows the MH curve in the hard axis direction.

As can be seen from FIG. 17, the coercive force Hc (a in the figure) of the CoFe film on the side not fixed to FeMn is about 500 A / m, which is higher than that of a normal CoFe single layer film of about 1600 A / m. The value was extremely low. Further, in the hard axis direction which is the signal magnetic field input side, as can be seen from FIG.
The coercive force Hc (b in the figure) of the e film becomes about 600 A / m,
The value was significantly lower than the Hc of the ordinary CoFe single layer film of about 1600 A / m.

Further, the resistance change characteristic of this magnetoresistive effect element was investigated, and its RH curve (resistance-magnetic field curve) is shown in FIG. As can be seen from FIG. 19, the rate of change in resistance ΔR
/ R has a high resistance change rate of about 9%, which is almost the same as that of the conventional Co-based spin valve film. The coercive force Hc (c in the figure) of the CoFe film on the side not fixed to FeMn is shown in FIG.
As expected from the above, the value was as low as about 500 A / m.

In this embodiment, Fe is used as the exchange bias layer.
Although a Mn film is used, it has been confirmed that good characteristics can be obtained by using an antiferromagnetic film such as NiO or an artificial lattice film having a structure such as (Co / Cu) n. Was done. Further, in this embodiment, the CoZrNb film is used as the high-resistance amorphous layer. However, a FeZr film, a FeZrN film, a CoZrN film, a FeTa
C film or NiFeX film (X: Rh, Nb, Zr,
Hf, Ta, Re, Ir, Pd, Pt, Cu, Mo, M
n, W, Ti, Cr, Au, or Ag) may be used. In particular, a microcrystalline film (Co-based nitride film, Co
In the case of the system-based carbonized film and the NiFeX film, the effect of promoting the fcc phase (111) orientation was also synergistic, and Hc was further reduced to 250 A / m in the easy axis direction, and the resistance change rate was improved to 10%.

For comparison, a magnetoresistive effect obtained by sequentially stacking a ferromagnetic film, an intermediate layer, a ferromagnetic film, and an exchange bias layer similar to FIG. 23 described later on a supporting substrate without providing a high resistance amorphous layer. The magnetic characteristics of the element were examined, and the MH curve thereof is shown in FIGS. 20 and 21. FIG. 20 shows an MH curve in the easy axis direction, and FIG. 21 shows an MH curve in the hard axis direction. The film forming conditions were the same as in Table 3 above.

As can be seen from FIG. 20, the coercive force Hc (d in the figure) of the CoFe film on the side not fixed to FeMn is about 2000 A / m, which is the Hc of a normal CoFe single layer film.
It showed a high value as well. Further, also in the hard axis direction, as shown in FIG. 21, the coercive force Hc (e in the figure) of the CoFe film on the side not fixed to FeMn is about 1400 A.
/ M, which is as high as Hc of a normal CoFe single layer film, and was insufficient as a magnetoresistive element.

(Embodiment 11) As shown in FIG. 22, a base film 36 of Cu or the like having a thickness of about 5 nm is formed on a support substrate 30, and an exchange bias layer 34, a ferromagnetic film 32, The non-magnetic film 33, the ferromagnetic film 32, and the high resistance amorphous layer 31 are sequentially formed, and the high resistance amorphous layer 3 is formed.
A lead 35 was formed on the first layer to prepare a magnetoresistive effect element. The film forming conditions were the same as in Table 3 above.

Even in the structure shown in FIG. 22, that is, in the case where the high resistance amorphous layer is formed as a layer above the exchange bias layer, low Hc could be obtained. In addition, since the amorphous layer has high resistance, the shunt effect did not reduce the magnetoresistance ratio even when this layer was the uppermost layer. In this case, it is desirable to provide a base film for controlling the crystal orientation of FeMn.

(Embodiment 12) CoPt is formed on the support substrate 41.
A Cr film 42 having a thickness of 8 nm is formed, and a resist 43 is formed thereon.
After applying, the resist 43 was patterned into a desired pattern and, as shown in FIG. 23A, was etched by ion milling or the like. At this time, it is desirable that the taper angle X of CoPtCr be closer to 90 °.

Next, as shown in FIG. 25B, the resist 43 after etching is not removed, and CoFe is removed in this state.
Ferromagnetic film 44 made of alloy, non-magnetic film 4 made of Cu or the like
5, a ferromagnetic film 44 and a high-resistance amorphous layer 46 were sequentially formed to fabricate a magnetoresistive element having a spin-valve structure. At this time, it is desirable that the taper angle Y of the resist 43 is closer to 90 °.

Next, after removing the resist 43, a lead 47 was formed on the high resistance amorphous layer 46. In addition,
The leads 47 may be formed before the resist 43 is removed. By manufacturing as described above, FIG.
As shown in (C), a spin valve structure sensitive to the interface state can be manufactured without deterioration in characteristics.

As in the above structure, a high coercive force film can be used without using the exchange bias layer made of FeMn or the like as the magnetization fixed film. As a material of the high coercive force film, it is desirable to use a material that can exhibit appropriate in-plane magnetic anisotropy without using a base film. Therefore, in this embodiment, a CoPtCr film satisfying this characteristic was used as a high coercive force film.

(Embodiment 13) As shown in FIG. 24, a high resistance amorphous layer 31 and a ferromagnetic film 3 are formed on a supporting substrate 30.
2, the non-magnetic film 33, the ferromagnetic film 32, and the high-resistance amorphous layer 31 were sequentially stacked, and the lead 35 was formed on the uppermost high-resistance amorphous layer 31 to manufacture a magnetoresistive effect element.

As shown in the structure of FIG. 24, the exchange bias layer made of FeMn, which is the magnetization fixed film, is not used, but the self-bias effect due to the effect of the demagnetizing field due to the magnetic field generated by the sense current or the shape is used. An antiferromagnetic magnetization arrangement between the magnetic films 32 may be realized.

In this case, the magnetic field generated by the sense current is applied in the film width direction (g direction in the drawing) so as to be opposite in the vertical direction with the ferromagnetic film 32 interposed therebetween. In order to reduce the magnetic field, the two ferromagnetic films 32 are antiferromagnetically coupled to each other. As a result, the two ferromagnetic films 32 can be coupled antiferromagnetically without the exchange bias layer. Therefore, the signal magnetic field Hs
Is applied in the longitudinal direction of the film (the direction f in the figure), the magnetizations of the two ferromagnetic films 32 rotate and are aligned in the longitudinal direction of the film to form ferromagnetic coupling. As a result, large △ due to spin-dependent scattering
R / R can be obtained.

(Embodiment 14) As shown in FIG. 25, C is formed as a high resistance ferromagnetic film 161 on a thermally oxidized Si substrate 160.
The film thickness of the oCr alloy film is 1 by the ion beam sputtering method.
The film was formed in nm. Next, on the high resistance magnetic film 161, a CoFe alloy film having a thickness of 3 nm as a first ferromagnetic film 162, a Cu film having a thickness of 2 nm as a non-magnetic film 163, and a CoFe alloy film having a thickness of 2 nm as a second ferromagnetic film 164. An alloy film was sequentially formed with a thickness of 3 nm to form a spin valve type laminated film.

After that, the antiferromagnetic film 16 is formed on the laminated film.
As No. 5, an FeMn film was formed with a thickness of 15 nm. On top of this, a protective film 166 is formed as necessary,
By forming 67a and 167b (interval: 10 μm), a spin-valve magnetoresistive element 168 was manufactured.

The resistance change rate of the spin-valve magnetoresistive element thus obtained was measured and found to be 14 at room temperature.
%.

For comparison, a spin valve magnetoresistive effect element was manufactured in the same manner as in Example 14 except that the high resistance ferromagnetic film 161 was not formed. When the characteristics of this spin-valve magnetoresistive element were evaluated in the same manner as in Example 14, the resistance change rate at room temperature was 12%.

(Embodiment 16) A first sapphire substrate was formed.
A Co ₉₀ Fe ₁₀ alloy film as a ferromagnetic film, a Cu film as a non-magnetic film, a Co ₉₀ Fe ₁₀ alloy film as a second ferromagnetic film, and an FeMn film as an antiferromagnetic film. At this time, the resistance change rate (Δρ / ρ ₀ ) was measured by changing the thickness (d _FeCo ) of the first and second ferromagnetic films. The result is shown in FIG. The thicknesses of the first and second ferromagnetic films were the same, the thickness of the Cu film was 2.2 nm, and the thickness of the FeMn film was 15 nm. In the magnetoresistive element, an electrode is formed on the antiferromagnetic film, if necessary, via a protective film made of Ta, Ni, NiCr or the like having excellent corrosion resistance and the like. As can be seen from FIG. 26, when d _FeCo is 5 nm or less, MR
It can be seen that the effect is increasing. Also, d _FeCo = 3 nm
A peak is taken in the vicinity, and a preferable range is 2 to 4 nm.

As the thickness of the sandwich structure of the ferromagnetic film / non-magnetic film (metal thin film) / ferromagnetic film becomes thin, the electron scattering at the surface not in contact with the metal thin film becomes large, and the resistance size effect Appears. The variation (Δρ) in the specific resistance of the sandwich structure is proportional to l ₀ / t, where t is the total film thickness of the sandwich structure and l ₀ is the mean free path. Although it changes depending on various conditions, as is clear from FIG. 26, when the Co-based ferromagnetic film is used, the ferromagnetic film thickness is 5 nm.
The following is preferable in order to obtain a good MR effect.

That is, when a material having a low resistance, for example, 30 μΩcm or less is in contact with the surface of the ferromagnetic film which is not in contact with the metal thin film, electrons pass through the interface and the specific resistance of 30 μΩcm or less is obtained. It will flow into the material with the effect, and effective surface scattering will be less likely to occur. Therefore, in order to cause effective surface scattering and utilize the size effect, it is effective to use a material having a thickness of 30 μΩcm or more or a thickness of a material in contact with the material of 5 nm or less.

In order to obtain a large MR effect by utilizing the size effect, it is preferable that the thickness of the Co type ferromagnetic film is 5 nm or less. At this time, as the intermediate metal thin film, C
It is desirable to use a metal having a small specific resistance such as u, Ag, or Au, and the thickness of the intermediate metal thin film is preferably smaller than 5 nm in order to utilize the size effect. If the thicknesses of the two ferromagnetic films are significantly different, the effect of surface scattering on the two ferromagnetic films is different, and the rate of change in magnetoresistance is small. For this reason, it is desirable that the ratio of the thicknesses of both ferromagnetic films is between 1: 1 and 1: 2.

(Example 16) As shown in FIG. 27, a CuPd alloy film was formed as a non-magnetic film 161 on a sapphire substrate 160 by RF sputtering to a thickness of 2 nm. Next, a CoFe alloy film having a thickness of 1 nm is formed as the first ferromagnetic film 162 on the non-magnetic film 161, and C is formed as the non-magnetic film 163.
The u film is 2 nm thick and CoF is used as the second ferromagnetic film 164.
An e-alloy film was sequentially formed with a thickness of 3 nm to form a spin valve type laminated film.

After that, the antiferromagnetic film 16 is formed on the laminated film.
As No. 5, an FeMn film was formed with a thickness of 15 nm. On top of this, a protective film 166 is formed as necessary,
By forming 67a and 167b, a spin-valve magnetoresistive element 171 was manufactured.

In this magnetoresistive effect element, the antiferromagnetic film 1
Since the second ferromagnetic film 164 is given unidirectional anisotropy by 65, the magnetization does not move while being fixed in one direction in a low magnetic field. On the other hand, the first ferromagnetic film 1
62 directs the magnetization in the direction of the magnetic field even in a low magnetic field. Therefore, by changing the external magnetization, the angle formed by the magnetizations of the two ferromagnetic films can be freely controlled. Note that the antiferromagnetic film 165 preferably has a thickness of about 1 to 50 nm in order to impart effective unidirectional anisotropy to the second ferromagnetic film 164.

The rate of change in resistance of the spin valve magnetoresistive effect element 171 thus obtained was measured.
Although the thickness of the ferromagnetic film 162 was reduced to 1 nm, the value was as high as 8% at room temperature. Further, the spin-valve magnetoresistive element 171 was formed to have a width of 2 μm ×
Processed into a fine shape with a length of 80 μm and the gap between Cu leads was 2 μm.
When used for reproduction of high-density magnetic recording with a narrow track width defined as m, Barkhausen noise could be removed.

For comparison, a spin valve magnetoresistive effect element was manufactured in the same manner as in Example 17 except that the nonmagnetic film 161 was not formed. When the characteristics of this spin-valve magnetoresistive element were evaluated in the same manner as in Example 17, the rate of change in resistance was as small as 3% at room temperature.

The thickness of the first ferromagnetic film 162 is set to 6 nm.
A spin-valve magnetoresistive element was manufactured in the same manner as in Example 16 except that the above conditions were satisfied. When the characteristics of this spin-valve magnetoresistive element were evaluated in the same manner as in Example 16, the resistance change rate was 6% at room temperature.
When high-density recording (narrow track width) reproduction was performed using the same reproduction fine element as in Example 16, Barkhausen noise due to a demagnetizing field was observed.

(Embodiment 17) As shown in FIG. 28, as a thin film 172 having a long mean free path, a GaAs film doped with Te so that the carrier concentration becomes 10 ²⁰ cm ⁻³ is formed on a thermally oxidized Si substrate 160. A film having a thickness of 10 nm was formed by the MBE method. Next, on the Te-doped GaAs film 172, a CoFe alloy film having a thickness of 1 nm as a first ferromagnetic film 162, a Cu film having a thickness of 2 nm as a non-magnetic film 163, and a CoFe alloy film as a second ferromagnetic film 164. Films are sequentially formed with a thickness of 4 nm,
A spin valve type laminated film was formed.

After that, the antiferromagnetic film 16 is formed on the laminated film.
As No. 5, an FeMn film was formed with a thickness of 15 nm. On top of this, a protective film 166 is formed as necessary,
By forming 67a and 167b, a spin-valve magnetoresistive element 173 was manufactured.

The resistance change rate of the spin valve magnetoresistive effect element thus obtained was measured and found to be 18 at room temperature.
%. The spin valve type magnetoresistive element is used for reproducing high density magnetic recording,
^{When the} output signal voltage at a sense current of ⁵ A / cm ² was measured, a good value of 1 mV _pp was obtained.

For comparison, Te-doped GaAs film 172
A spin-valve magnetoresistive element was fabricated in the same manner as in Example 17, except that no was formed. When the characteristics of the spin-valve magnetoresistive element were evaluated in the same manner as in Example 17, the rate of change in resistance was as small as 2% at room temperature.

(Example 18) 10 nm thick on a glass substrate
Cu film is formed as a base film, and Co ₉₀ Fe ₁₀ is formed thereon.
A film was formed. The Cu film and the Co ₉₀ Fe ₁₀ film are RF2
The film was formed by the polar sputtering method. Note that the sputtering was performed under the following sputtering conditions by applying a unidirectional magnetic field of about 4000 A / m to the vicinity of the substrate during film formation using a permanent magnet.

Preliminary exhaust 1 × 10 ⁻⁴ Pa or less Ar sputter gas pressure 0.4 Pa High-frequency input power CoFe: 300-500 W Cu: 160 W Sputtering speed CoFe: 0.5-1 nm / s Cu: 1 nm / s In this way fabricated Co ₉₀ Fe ₁₀ film of Hc is shown in Figure 29 the thickness of the relationship (hard axis) and Co ₉₀ Fe ₁₀ film.
FIG. 29 also shows a case where a Co ₉₀ Fe ₁₀ film was directly formed on a glass substrate without providing a Cu base film for comparison. The coercive force Hc was measured by a vibrating magnetometer.

As can be seen from FIG. 29, the normal Co ₉₀ Fe ₁₀ film having no Cu underlayer has a high Hc of 2000 A / m or more at a film thickness of 20 nm or less. On the other hand, when a Cu base film is provided, Hc is used for a 20 nm-thick Co ₉₀ Fe ₁₀ film.
Was slightly reduced, but when the film thickness was 10 nm or less, it was 400 to 400 nm.
Hc was significantly reduced to 900 A / m. Thus, it was found that by providing a Cu underlayer between the glass substrate and the Co ₉₀ Fe ₁₀ film, the Hc of the Co ₉₀ Fe ₁₀ film could be reduced. In particular, when the thickness of the Cu underlayer was at least one atomic layer, the above-described effect of reducing Hc was recognized. Note that Cu
When a Co film is formed on the base film in the same manner, Co
Hc did not decrease as much as the Fe film.

(Example 19) Thickness 5-6 on a glass substrate
nm Cu underlayer film is formed, and Co ₉₀ is formed on the Cu underlayer film.
Fe ₁₀ film, 2 nm thick Cu intermediate layer, and Co ₉₀ Fe ₁₀
The film was formed sequentially. The conditions for forming these films were the same as in Example 18.

This laminated film (Cu / CoFe / Cu / Co
FIG. 30 shows the relationship between Hc (in the hard axis direction) and the film thickness of the Co ₉₀ Fe ₁₀ film in Fe). FIG. 30 shows FIG.
In the same way as above, the C
o showed ₉₀ Fe ₁₀ as a film was formed.

As can be seen from FIG. 30, in the laminated film in which the Cu underlayer is not provided, Hc rapidly increases when the film thickness of the unit Co ₉₀ Fe ₁₀ film is 5 nm or more, but Hc is 80 when the film thickness is 3 nm or less.
0 A / m. Thus, Hc can be reduced by simply providing the Cu intermediate layer. Further, Cu
By providing a base film, Hc can be further reduced, and when the thickness of the unit Co ₉₀ Fe ₁₀ film is 7 nm or less, 220 to 400 A /
It turns out that Hc of low m is obtained. Therefore, C
In the case of the Co ₉₀ Fe ₁₀ laminated film using the u underlayer film and the Cu intermediate layer, Hc can be significantly reduced as compared with the case of the eighteenth embodiment.

Cu5 nm / Co ₉₀ Fe ₁₀ 2.2 nm /
Cu2nm / Co ₉₀ Fe ₁₀ magnetization curves of 2.2nm laminated film of the (easy axis) shown in FIG. 31. As can be seen from FIG. 31, even when the magnetic field is 0, the residual magnetization is 90% or more.
It can be seen that the magnetizations of the two Co ₉₀ Fe ₁₀ ferromagnetic films exhibit a ferromagnetic magnetization behavior instead of antiferromagnetic.

(Example 20) The unit film thickness of the Co ₉₀ Fe ₁₀ film was 1.5 nm, and the unit film thickness of the Cu film was 1.5 nm.
A (CoFe / Cu) n film was formed under the film forming conditions shown in Example 18, and the relationship between Hc and the number of laminations n was examined. The result is shown in FIG. In this case, Co ₉₀ on the glass substrate
Fe ₁₀ film and Cu film stacked in this order, Cu film and Co film
_{A 90} Fe ₁₀ film stacked in this order (Cu in the first layer is considered to correspond to the base film) was examined.

As can be seen from FIG. 32, in the case where the number of laminations is 2, when the Co ₉₀ Fe ₁₀ film is formed first,
Hc is slightly higher at 650 A / m, but when the number of laminations is 4 to 8, Hc is as low as 100 to 300 A / m regardless of whether the Co ₉₀ Fe ₁₀ film or the Cu film is first. This is because the effect of the Cu underlayer weakens as the number of laminations increases, and C
It is considered that Hc is lowered regardless of the presence or absence of the u underlayer (the first layer Cu film). The magnetization curve in this case also had a shape showing ferromagnetic coupling as in FIG.

From the observation of a cross-section transmission electron microscope and the measurement of the diffraction peak half width of the X-ray diffraction curve, this laminated film has a large crystal grain size, that is, it is continuous at the interface between the Cu film and the Co ₉₀ Fe ₁₀ film. It was found that the crystal grew epitaxially. Therefore, this laminated film is different from a conventional multilayer film of Fe / C or the like which exerts soft magnetism by a microcrystal effect utilizing a crystal growth blocking effect at an interface between a nonmagnetic film and a ferromagnetic film. Since there is no extra increase in resistance, application to a magnetoresistive film utilizing spin-dependent scattering is possible.

(Example 21) (Co ₉₀ Fe ₁₀ / Cu) n
In the film, it is known that the magnetization of the ferromagnetic film adjacent to the Cu film is antiferromagnetically coupled or ferromagnetically coupled depending on the Cu film thickness. FIG. 33 shows (Co ₉₀ Fe ₁₀ (1
nm) / Cu) ₁₆ Hs (saturation magnetic field) in the hard axis direction
And the film thickness of the unit Cu film are shown. Cu film thickness is 1
When set to around 2 nm, a large Hs (12 to 240 kA /
m). In addition, a magnetization curve showing antiferromagnetic coupling in which the residual magnetization is greatly reduced as shown in FIG. 34 also in the easy axis direction. On the other hand, at other film thicknesses, Hs (1000 to 2000 A / m) corresponding to the induced magnetic anisotropy of Co ₉₀ Fe ₁₀ is exhibited as in the magnetization curve shown in FIG. As for the magnetization curve of No. 1, the residual magnetization was 90% or more, and the anti-ferromagnetic coupling was not exhibited.

As can be seen from FIG. 33, ferromagnetic coupling can be obtained by setting the film thickness to an intermediate value of, for example, about 1.5 nm. In the case of ferromagnetic coupling, the permeability in the hard axis direction, which is important for application of a magnetic sensor such as a magnetic head, can be increased because Hs is low. As described above, in the present embodiment, the thickness of the Cu film is desirably an intermediate value that does not cause antiferromagnetic coupling, unlike a conventional artificial lattice film exhibiting a giant magnetoresistance effect.

(Embodiment 22) The ferromagnetic laminated unit 51 was formed on the substrate 50 under the same film forming conditions as in Embodiment 18. Here, the ferromagnetic laminated unit 51 is the same as that of Example 20 and Example 2.
It refers to a laminated film of a Cu film which is a non-magnetic film shown in 1 and a Co ₉₀ Fe ₁₀ film which is a ferromagnetic film. Next, a nonmagnetic film 52 having a thickness different from that of the nonmagnetic film in the ferromagnetic laminated unit was formed on the ferromagnetic laminated unit 51, and the ferromagnetic laminated unit 51 was formed thereon. Then on top of it FeM
An antiferromagnetic film 53 made of n, NiO, NiCoO or the like was formed, and a protective film 54 was further formed thereon. This protective film 54 is formed as needed. Finally, an electrode terminal 55 was formed on the protective film 54 in order to supply a current to the edge portion, thereby producing a magnetoresistive element shown in FIG.

Here, by forming the ferromagnetic laminated unit 51 and the antiferromagnetic film 53 in a unidirectional magnetic field, an exchange bias is applied to the ferromagnetic laminated unit 51 which is in direct contact with the antiferromagnetic film 53. You can Since the magnetization of the ferromagnetic film in the ferromagnetic multilayer unit 51 exchange-coupled to the antiferromagnetic film 53 is fixed, a CoFe single-layer film having a slightly lower soft magnetism may be used instead of the ferromagnetic multilayer unit 51. Good. Further, the CoFe / Cu interface with ferro-coupling does not necessarily have to be flat, and as shown in FIG.
The same effect is exhibited even when Fe is mixed.

The ferromagnetic laminated unit 51 is (Co ₉₀ Fe ₁₀ 1nm
/ Cu 1.2 nm) ₄ films, and the non-magnetic film 52 has a thickness of 2.5
nm Cu film and the antiferromagnetic film 53 is 10 nm thick FeM
FIGS. 37 and 38 show the magnetization curve and the resistance change characteristic (the magnetic field direction is the easy axis direction) of the magnetoresistive element in which the protective film 54 is a Cu film having a thickness of 6 nm as the n film. The resistance was measured by a four-terminal method.

As can be seen from FIGS. 37 and 38, H
> 800 A / m, the magnetization is antiferromagnetically coupled between the two ferromagnetic laminate units 51 and H <500 A / m
Thus, the magnetization is ferromagnetically coupled between the two ferromagnetic laminated units 51. That is, H = 500 to 800 A /
It can be seen that the magnetization changes from ferromagnetic coupling to antiferromagnetic coupling during m. H = 500 to 800 A / m
The resistance changes greatly due to a small magnetic field region, that is, a small hysteresis. At this time, the resistance change rate ΔR / R
Is 8%.

For comparison, the magnetization of the magnetoresistive effect element of the spin valve structure shown in FIG. 35, which is composed of a Co ₉₀ Fe ₁₀ single layer film (the ferromagnetic lamination unit 51 is replaced with a Co ₉₀ Fe ₁₀ single layer film). The curves and resistance change characteristics are shown in Fig. 3, respectively.
9 and FIG.

As can be seen from FIGS. 39 and 40, the magnetization curve has a larger hysteresis than the resistance change of FIG. 38, and as a result, the resistance change characteristic also has a large hysteresis. Further, ΔR / R is about 6.5%, which is shown in FIG.
It is a value smaller than the resistance change of.

From the above description, the magnetoresistive effect element of the spin valve structure using the ferromagnetic laminated film of the present invention has good soft magnetism and can obtain a large resistance change with a slight magnetic field.
Further, it can be seen that since the Co ₉₀ Fe ₁₀ / Cu interface exists inside the ferromagnetic laminated unit, the rate of change in resistance is large.

Although the embodiments of the (CoFe / Cu) n laminated film have been described in detail above, this spin valve structure has another ferromagnetic film (eg, NiFe, NiFeCo, C).
o) and another non-magnetic film (Cu-based alloy or the like) can be expected to have the same effect. Next, in the spin valve structure in FIG. 35, the resistance change rate in the easy axis direction and Hc when the ferromagnetic laminated unit 51 is changed to various ferromagnetic coupling multilayer films are shown in Table 5 below.

[0212]

[Table 5]

As can be seen from Table 5, even when the ferromagnetic multilayer film of a combination other than CoFe / Cu is used, the Hc can be reduced as compared with the spin valve film using the single-layer magnetic film (see Table 2), and it is equivalent. It is understood that the above resistance change rate can be realized.

(Embodiment 23) As a ferromagnetic lamination unit 51 on the substrate side in FIG.
Using Co ₉₀ Fe ₁₀ of nm, the anti-ferromagnetic film 53 side of the case of using the thickness 8nm of Co ₉₀ Fe ₁₀ single layer in the ferromagnetic stack unit 51 the magnetization curve and the resistance change characteristics, respectively Figure 41
(A), FIG. 41 (B) and FIG.

As can be seen from FIG. 41 (A), Hc shows a relatively large value of 800 A / m or less in the easy axis direction, but as shown in FIG. 41 (B), it is 1 in the hard axis direction.
It shows a low value of 00 A / m or less. As can be seen from FIG. 42, the resistance change rate ΔR / R is 7.2 in the easy axis direction.
% In the hard axis direction. The low resistance change rate in the hard axis direction is considered to be due to the insufficient antiparallel magnetization alignment due to ferrocoupling between the two ferromagnetic layers, and the hard magnetic film promotes the antiparallel magnetization alignment. ΔR of the same degree as the easy axis direction by applying a bias magnetic field
/ R. That is, a Cu underlayer and Co
Good soft magnetism and high ΔR even when a laminated film of ₉₀ Fe ₁₀ film is used
/ R are obtained.

(Example 24) On the substrate 50, the ferromagnetic film laminated unit 51 used in Example 22 and the nonmagnetic film 52 having a different thickness from the nonmagnetic layer in the ferromagnetic film laminated unit 51 are alternately arranged. Was laminated at least twice more. further,
A protective film 54 was formed on the uppermost non-magnetic film 52. This protective film 54 is formed as needed. Finally, the electrode terminal 55 for supplying a current to the edge portion is formed, and the electrode terminal 55 is
The magnetoresistive effect element shown in was produced.

The ferromagnetic laminated unit 51 is (Co ₉₀ Fe ₁₀ 1nm
/ Cu 0.6 nm) ₄ film and the non-magnetic layer 52 has a thickness of 2.2.
FIG. 44 and FIG. 45 show the magnetization curve in the hard axis direction and the resistance change characteristics when a Cu film having a thickness of nm and a stacking number n of 8 were used.

As can be seen from FIGS. 44 and 45, the saturation magnetic field Hs shows a relatively small value of 6000 A / m,
Hc shows a small value of 240 A / m. At this time, the resistance change rate is 12% or less, the magnetic field at which the resistance change is saturated almost matches the saturation magnetic field Hs in the magnetization curve, and the hysteresis almost matches Hc of the magnetization curve. This shows that a small change in the magnetic field shows a large rate of change in resistance.

Example 25 MgO processed into a mirror state
On the (110) plane of the substrate 60 (Co ₉₀ Fe ₁₀ 1nm / Cu
1.1 nm) ₁₆ laminated film 61 was formed. This laminated film 61 was patterned into a 1 × 8 mm ² stripe shape using a metal mask. Next, an electrode terminal 62 for supplying a current to the edge portion was formed on the laminated film 61 to produce a magnetoresistive element. A Cu film having a thickness of 5.5 nm may be formed on the laminated film 61 as a protective film. Also, CoFe
The composition of the system-based alloy film was set to Co ₉₀ Fe ₁₀ from the viewpoint of showing a large rate of resistance change [Journal of Applied Magnetics, 16 , 313 (1992)] and soft magnetic properties.

In this case, a Co ₉₀ Fe ₁₀ film was formed on the (110) surface of the MgO substrate 60. This is because when formed from a Cu film, a large resistance change of 10% or more cannot be obtained. In FIG. 46, a waveform line shown in the laminated film 61 indicates a cross section of the main growth surface. An MR sense current (Is) flows in a direction in which the main growth surface fluctuates.

Here, a multi-source simultaneous sputtering device was used as a film forming device for forming the laminated film 61. This sputtering apparatus is configured so that a Co ₉₀ Fe ₁₀ target can be RF-sputtered and a Cu target can be DC-sputtered, and a film is formed by passing a substrate to which a DC bias has been applied alternately on each target. is there. In addition, a cryopump was used as the main exhaust pump. Using this film forming apparatus, the inside of a vacuum chamber is 5 × 1
After evacuating to 0 ^-7 Torr or less, A
An r gas was introduced, and sputtering was performed at about 3 mTorr.

The rate of change in resistance and the crystal structure of the obtained magnetoresistive effect element were examined. The resistance change rate was obtained by measuring the resistance change in the static magnetic field direction by a four-terminal method. The current density at this time was 2.0 to 2.5 KA / cm ² . The crystal structure was evaluated by measuring a θ-2θ scan and a rocking curve relating to the main diffraction plane by an X-ray diffraction method under the following measurement conditions.

X-ray diffraction measurement conditions (1) θ-2θ scan Cu-Kα, 40 kV, 200 mA Scan width: 2θ = 2 to 100 ° Step width: 0.03 ° Coefficient time: 0.5 seconds (2) Rocking curve Cu-Kα, 40 kV, 200 mA Scan width: 2θ = 20 to 60 ° Step width: 0.04 ° Coefficient time: 0.5 seconds FIGS. 47A and 47B show the laminated film of the magnetoresistive element. The X-ray diffraction curve by a (theta) -2 (theta) scan is shown.
As shown in FIG. 47B, fc is around 2θ = 75 °.
A strong diffraction peak corresponding to the c-phase (220) plane reflection can be confirmed. From this, it can be seen from the X-ray diffraction curve that the main growth plane of the laminated film is the fcc phase (220) plane which is distorted in one direction. Note that the peak near 2θ = 4 ° in FIG. 47A is diffraction due to the lamination period (up to 2.1 nm).

Next, regarding this main growth surface, [100]
Rocking curves were measured from the axial direction and the [110] axis direction. The results are shown in FIGS. 48 (A) and 48 (B).
Shown in FIG. 48A shows a rocking curve measured from the [110] axis direction. From this, one peak can be confirmed near θ = 38 °. On the other hand, FIG. 48B shows a rocking curve from the [100] axis direction. This confirms the presence of two peaks around θ = 33 ° and 41 °.

FIG. 48 is shown in FIGS. 49 (A) and 49 (B).
3 is a conceptual diagram of a film structure determined from a rocking curve of FIG. In FIG. 49 (A), the undulating layer is f of the main growth surface.
The cc phase (110) plane is shown. The average crystal growth plane measured by the θ-2θ scan X-ray diffraction method is (110), but this (110) plane fluctuates in the [100] axis direction. On the other hand, the fluctuation in the [110] axis direction is extremely small.
This corresponds to two peaks ([100] axis direction measurement) of the rocking curve shown in FIG. 48 (B) and one peak ([110] axis direction measurement) shown in FIG. 48 (A).

FIG. 49B shows the in-plane component distribution of the normal to the growth surface. This in-plane anisotropy of the film has a large distribution in the [100] axis direction and a small in-plane distribution in the [110] axis direction due to a large fluctuation in the [100] axis direction.
As will be described later, the resistance change rate (／ R / R) when the MR sense current flows in the [110] axis direction is about 30%, whereas when the MR sense current flows in the [100] axis direction, , About 3
Indicates 5%.

Next, the magnetic characteristics of this laminated film were measured.
The magnetic curves based on the results are shown in FIGS.
It shows in (B). FIG. 50A shows that the external magnetic field H is [100].
FIG. 50 shows a magnetization curve when applied in parallel to the axis, and FIG.
(B) shows a magnetization curve when an external magnetic field H is applied in parallel to the [110] axis. The magnetic characteristics of the magnetoresistive effect element were determined by a vibration type magnetometer (VSM) with a maximum applied magnetic field of 1.2
It was measured in A / m. Further, the magnetization amount M of the magnetization curve is shown by normalizing the saturation magnetization Ms.

As can be seen from FIGS. 50 (A) and 50 (B), the [100] axis is the easy magnetization axis and the [110] axis is the hard magnetization axis. At this time, the saturation magnetic field of the easy axis is about 240 kA / m, and the saturation magnetic field of the hard axis is about 96 kA / m.
It is 0 kA / m.

As described above, in this embodiment, the laminated film in which the ferromagnetic film and the non-magnetic film are sequentially laminated at least once on the substrate is provided, and the direction of the sense current is the crystal orientation plane of the laminated film. Provided is a magnetoresistive effect element characterized by being set in a direction along a fluctuation direction.

In this example, the normal line of the main crystal orientation plane of the laminated film has a component in the film plane due to the fluctuation of the crystal orientation plane, and the in-plane component has anisotropy. Alternatively, a normal line of a plane defect generated in the crystalline laminated film has fluctuation in the film plane, and the fluctuation has anisotropy in the film plane. The direction in which the anisotropy is strong is a direction in which ferromagnetic atoms and non-magnetic atoms are likely to be mixed on the atomic plane on which the film is grown.

By passing the sense current in that direction, that is, in the direction in which the anisotropy due to the in-plane component of the film is maximized, the probability that electrons will be spin-dependent scattered increases. As a result, the magnetoresistive element exhibits a higher resistance change rate.

Example 26 Various magnetoresistive effect elements having the same laminated film structure as in Example 25 were prepared by changing the bias applied to the substrate. FIG. 51 shows the bias voltage dependence of the resistance change rate. In addition, (11 of the MgO substrate
The [100] axis and the [11] which are respectively orthogonal to the
The measurement was performed by passing a current parallel to the [0] axis. As can be seen from FIG. 51, the bias dependency of the resistance change rate is weak on each of the axes, and the values are about 35% on the [100] axis and about 30% on the [110] axis. That is, it can be seen that the [100] axis has a larger resistance change rate than the [110] axis.

(Example 27) A laminated film was formed into (Cu2nm / Co).
_A magnetoresistive effect element was produced in the same manner as in Example 25 except that the ₉₀ Fe ₁₀ 1 nm) ₁₆ film was used.

When the thickness of the Cu film is increased to 2 nm as described above, the rate of change in resistance when a current is passed in the [100] axis direction is about 25%, and about 19% in the [110] axis direction. Met. Therefore, it can be seen that even if the thickness of the Cu film is increased, the direction dependency of the resistance change rate is maintained. Also in this case, the rocking curve of the main growth plane (fcc phase (220) plane) has [1] as shown in FIG.
Two peaks were confirmed on the [00] axis, and one peak was confirmed on the [110] axis as shown in FIG.

With the same structure, the film thickness of the Cu film and C
Even if the thickness of the o ₉₀ Fe ₁₀ film is changed from 0.3 nm to 10 nm, the tendency of the rocking curve does not change from the above, and the fluctuation in the [100] axis is larger. The resistance change rate also tended to be higher on the [100] axis.

In addition, the number of laminations is set to 2 to 70 with the same structure.
Even if it was changed, the tendency of the rocking curve and the resistance change rate did not change, and a larger resistance change was obtained by flowing the sense current in the [100] axis direction.

(Example 28) A laminated film was formed into (Ru1nm / Co).
_A magnetoresistive effect element was produced in the same manner as in Example 26 except that the ₉₀ Fe ₁₀ 1 nm) ₁₆ film was used.

The ΔR / R of this magnetoresistive element is [1
[00] [110] when the sense current flows in the axial direction
It was larger than when a sense current was passed in the axial direction. Also,
The above tendency was observed even when the thickness of the Ru film was changed.

This phenomenon is caused by C ₉₀ instead of Co ₉₀ Fe ₁₀ film.
This was confirmed even when the o film was used. In addition to Ru, A
Even when g, Au, Pd, Pt, and Ir are used for the material of the laminated film, the ratio depends on the axial direction on the (110) plane of the MgO substrate.
The difference of R / R was confirmed.

(Example 29) A laminated film (Cu1.1 nm /
Example 2 except that a Ni ₈₀ Fe ₂₀ 1.5 nm) ₁₆ film is used.
A magnetoresistive effect element was produced in the same manner as in 5.

[10] of the laminated film of this magnetoresistive effect element
0] When a sense current was passed in the axial direction, the resistance change rate was 21%. On the other hand, when a sense current was passed in the [110] axis direction, the resistance change rate was 17%. Also,
This laminated film is also the same as the case of the Co ₉₀ Fe ₁₀ / Cu laminated film,
The crystal growth plane was the fcc phase (110) plane, and the rocking curve measurement showed that the growth plane fluctuated in the [100] axis direction. Incidentally, it showed the same tendency even when the thickness of the film thickness and the Cu film of Ni ₈₀ Fe ₂₀ film is changed from 0.5 nm to 50 nm.

Further, Co and CoF are used as materials for the ferromagnetic film.
Even if e alloy, NiFe alloy, Fe, FeCr alloy or the like is used, Cu, Au, Ag, Cr, R
Even when u, CiNi alloy or the like was used, it was found that a large resistance change rate was exhibited if the crystal axis direction in which the main growth surface of the laminated film fluctuated was parallel to the sense current direction.

(Example 30) (110) of GaAs substrate
A 1.5 nm thick Co film, a 50 nm thick Ge film, and a 1.5 nm thick Au film were formed on the surface. Furthermore, it is shown in FIG. 53 using the MBE method (Cu0.9 nm / Co
₉₀ Fe ₁₀ 1 nm) ₂₀ laminated film was formed. In the figure, 69 indicates a Cu film and 71 indicates a Co ₉₀ Fe ₁₀ film. Further, a Ge film having a thickness of 5 nm was formed as a protective film on the laminated film to manufacture a magnetoresistive element. This laminated film has fcc phase (111)
It showed surface growth. At this time, the resistance change rate was about 15% regardless of the direction of the sense current.

Next, a magnetoresistive effect element was produced with the Au underlayer having a thickness of 0.8 nm and the other structures being the same as above.

Observation of the two obtained magnetoresistive elements with a transmission electron microscope revealed that the thickness of the Au underlayer was 1.5.
Those having nm had almost no lattice defects and very good crystallinity. On the other hand, if the thickness of the Au underlayer is 0.
The 8 nm one showed {111} plane orientation, but the {1}
Stacking faults were observed as the 00 ° plane slipped in the <110> axis direction. Also, when the resistance change rate in the <211> axis and the <110> axis direction of this magnetoresistance effect element was measured, it was about 15% in the <110> axis direction.
It increased to 17% in the <211> direction. As a result,
It can be seen that the presence of a directional defect causes the sense current to have a directional dependence of the resistance change rate.

FIG. 53 shows an atomic arrangement diagram of the laminated film in FIG. The case where a current flows in the <211> direction due to the {100} atom plane shifting in the <110>direction;
It can be seen that the number of interfaces encountered per unit length is different when flowing in the <110> direction, and is greater in the <211> direction.
The crystal axis direction dependence of the number of spin-dependent interface scattering sites of conduction electrons generated by lattice defects having such a direction is as follows.
It was found that twin defects also occurred in addition to the stacking faults described above. An example will be described below.

Thickness of 3 nm on (100) surface of GaAs substrate
An Au underlayer is formed, and (Co ₉₀ Fe ₁₀
(1 nm / Cu 1.1 nm) ₁₆ laminated films were formed. This laminated film exhibited fcc phase (100) plane orientation. At this time, <1
Twin> occurred with the 11> axis as the central axis. FIG. 55 shows the atomic arrangement when the cross section of the laminated film is observed from the <110> direction. As can be seen from FIG. 54, generation of twins around the <111> axis causes Cu in the <110> direction,
It can be seen that an interface with Co or Fe atoms appears.

The dependence of the resistance change rate of this laminated film on the sense current direction was measured in the <110> axis direction and the <100> axis direction. FIG. 55 shows the correlation between the twin plane and the current direction of the laminated film grown on the {100} plane and the resistance change rate. FIG.
As can be seen from FIG.
When the sense current is applied in the <100> axis direction, the value is 16% when the sense current is applied in the <100> axis direction. Thus, the resistance change rate of the <110> axis that intersects the {111} plane at a large angle appeared high. On the other hand, when twins did not occur, the sense current direction dependency of the rate of change in resistance could not be confirmed.

(Example 31) On a glass substrate (Cu1.
1 nm / Co ₈₁ Fe ₉ Pd ₁₀ 1 nm) ₁₆ artificial lattice film was formed. The formation of the artificial lattice film was performed while applying a DC bias to the substrate. The resistance change rate was measured by changing the magnitude of the applied DC bias, and the dependence (bias dependence) of the DC bias applied to the substrate is shown in FIG.

As can be seen from FIG. 56, the resistance change rate increases as the DC bias increases, and shows a maximum value of about 28% at bias -50V. Further, when the DC bias is increased, the resistance change rate decreases.

When the crystallinity of various artificial lattice films produced by changing the DC bias was evaluated, the main growth planes of all the artificial lattice films were fcc phase (111) plane growth. Here, 2θ = 4 reflected from the lamination period (2.1 nm)
Long-period structure reflection intensity appearing in the vicinity of ° and 2θ = 44 °
FIGS. 57 and 58 show the bias dependence of the peak intensity of the main growth surface reflected from the fcc phase (111) surface appearing in the vicinity.

As can be seen from FIG. 57, the bias dependence of the long period structure reflection intensity shows a slight maximum at a bias of about −20 V, but it cannot be said that there is a strong correlation with the bias. Also, as can be seen from FIG.
The bias dependency of the c-phase (111) surface reflection intensity also shows a slight maximum around a bias of -10 V, but cannot be said to have a strong correlation with the bias.

Further, by using the CoFe alloy system as the ferromagnetic film, bulk scattering of spin-dependent scattering becomes large, and the structure of the interface becomes less sensitive than in the case of using the Co system film as the ferromagnetic film. It is reported that when a Co-based film is used as the ferromagnetic film, the rate of change in resistance greatly depends on the film structure.

Next, FIG. 59 shows the bias dependence of the coercive force (Hc). As can be seen from FIG. 59, bias -5
Good soft magnetic properties of 200 A / m or less are exhibited up to about 0 V, but the coercive force starts to increase from about -60 V. Therefore, by selecting the magnitude of the DC bias to be applied, it is possible to select the optimum conditions for the rate of resistance change and the coercive force. Even when a Si substrate, a ceramic substrate, a GaAs substrate, and a Ge substrate were used instead of the glass substrate, the optimum points of the resistance change rate and the coercive force could be selected in the same manner.

(Embodiment 32) Here, an embodiment of the present invention in which the signal magnetic field is detected by the magnetization rotation of both of the two ferromagnetic films having the spin-dependent scattering ability will be described.

As shown in FIG. 60, a base film 81 for controlling the orientation of an antiferromagnetic film, an antiferromagnetic film 82, a ferromagnetic film 83 having a spin-dependent scattering ability, a nonmagnetic film 84, are formed on a substrate 80.
A ferromagnetic film 85 and an antiferromagnetic film 82 were sequentially formed.
Further, an electrode terminal 86 was formed on the uppermost antiferromagnetic film 82. A protective film may be formed on the antiferromagnetic film 82 as needed. When the antiferromagnetic film 82 is made of FeMn, the material of the base film 81 is Cu, CuV, Cu.
Cu alloy such as Cr, non-magnetic fcc phase such as Pd or N
A metal having a magnetic fcc phase, such as iFe or CoFeTa, is desirable. At this time, even if the magnetic material is thinner (that is, there is less shunt flow), a good exchange bias can be applied. The antiferromagnetic film 82 is made of FeMn, NiO,
It is made of PtMn or the like and has a thickness of 5 to 50 nm. The ferromagnetic films 83 and 85 are made of NiFe, Co, CoFe, NiF
It is made of eCo or the like, and has a thickness of 0.5 to 20 nm.
The nonmagnetic film 84 is made of Cu, Au, Ag, or the like, and has a thickness of 0.5 to 10 nm. Further, the antiferromagnetic film 82 does not need to be formed on the entire surface of the ferromagnetic film 85,
May be formed only on both side edges (near the electrode terminals 86).

Here, at least during the formation of the ferromagnetic film 83, a static magnetic field in one direction is applied in the x direction (sense current direction) in FIG. As a result, an exchange coupling bias magnetic field is applied to the ferromagnetic film 83 in the direction of the static magnetic field. On the other hand, at least during the formation of the antiferromagnetic film 82, a static magnetic field is applied in a direction (minus x direction) different from the direction of the magnetic field applied during the formation of the ferromagnetic film 83 by 180 °. As a result, the ferromagnetic film 83 is 1
An exchange coupling bias magnetic field is applied to the ferromagnetic film 85 in directions different by 80 °. As a result, the angle between the magnetizations of the two ferromagnetic films 83 and 85 becomes antiparallel when the signal magnetic field is zero. Note that the signal magnetic field Hs is applied in the y direction in the figure.

As a method of applying a bias magnetic field in the opposite direction to the ferromagnetic films 83 and 85 by the antiferromagnetic film 82, there is the following method. Films having different Neel temperatures are used as the two antiferromagnetic films 82, respectively, and a static magnetic field heat treatment is performed at a temperature higher than these Neel temperatures. 180 direction
° Invert. As a result, a bias magnetic field in the opposite direction can be applied to the ferromagnetic films 83 and 85.

Unlike the conventional spin-valve structure film, the present embodiment utilizes the magnetization rotation of the ferromagnetic film to which the exchange bias from the antiferromagnetic film is applied, so that the exchange bias magnetic field is Barkhausen. It is desirable that the magnetic field is not so strong as to suppress noise. For example, it varies depending on the track width of the applicable head, but is at most 5 kA.
/ M. However, the current spin-valve structure film generally uses an exchange bias magnetic field by an antiferromagnetic film made of FeMn.
When an n film and a ferromagnetic film such as a NiFe film are directly laminated,
An exchange bias of kA / m or more occurs. In order to reduce the exchange bias, a method for inserting an exchange bias adjusting film, for example, a ferromagnetic film or a non-magnetic film having a low saturation magnetization, between the antiferromagnetic film and the ferromagnetic film, or a method shown in FIG. As described above, the nonmagnetic films 87 and 88 are interposed between the ferromagnetic films 83 and 85, that is, the ferromagnetic films 83 and 8 are interposed.
5 to 83a and 83b, 85a and 85b respectively
There is a method of separating.

In the method of interposing the nonmagnetic film in the ferromagnetic film, the ferromagnetic films 83a and 85 on the side in contact with the antiferromagnetic film 82 are used.
While a strong exchange bias is applied to a, a weak exchange bias is applied to the ferromagnetic films 83b and 85b that are not in contact with the antiferromagnetic film 82. The ferromagnetic film 8 not in contact with the antiferromagnetic film 82 depends on the type of the material of the nonmagnetic films 87 and 88 and the thickness thereof.
The magnitude of the exchange bias to 3b and 85b can be reduced.

Here, the angle formed by the magnetizations of the ferromagnetic films 83a and 83b and the angle formed by the magnetizations of the ferromagnetic films 85a and 85b are changed from the ferromagnetic arrangement to the antiferromagnetic arrangement by the magnetization rotation by the signal magnetic field. However, the angle formed by the magnetizations of the ferromagnetic films 83b and 85b in the central portion of the film is changed from the antiferromagnetic arrangement to the ferromagnetic arrangement. Therefore, the former and latter spin-dependent scattering cancel each other out. Therefore, the ferromagnetic films 83a, 85a and the nonmagnetic films 87, 8
It is desirable that the material of No. 8 has a high resistance without spin-dependent scattering ability. Further, it is desirable that the thickness of the ferromagnetic films 83a and 85a on the side in contact with the antiferromagnetic film 82 be smaller than the thickness of the ferromagnetic films 83b and 85b on the side not in contact with the antiferromagnetic film 82.

With the above arrangement, the magnetization directions of the ferromagnetic films 83 and 85 can be aligned antiparallel to each other when the magnetic field is 0. As a result, first, even when a signal magnetic field is applied in the hard axis direction (the y direction in the figure) suitable for the magnetic head, the angle between the magnetizations of the two ferromagnetic films becomes 0 due to the rotation of the magnetizations of the two ferromagnetic films. A state changing up to 180 ° can be realized, and a high resistance change rate comparable to the easy axis direction can be realized. Second,
Since a bias magnetic field is applied to the two ferromagnetic films, domain walls can be eliminated from both ferromagnetic films, and Barkhausen noise can be suppressed. Third, the method in which the sense current and the signal magnetic field are orthogonal to each other has both a normal magnetoresistance effect and a resistance change due to spin-dependent scattering, which are remarkable when using a NiFe film or the like which has been canceled in the conventional spin valve structure. And an increase in ΔR / R can be expected.

(Example 33) In Example 32, a method of making the magnetizations of both antiferromagnetic films antiparallel by using two antiferromagnetic films was shown. However, it is not always necessary to apply a bias magnetic field only with the antiferromagnetic film, and it is also possible to use a leakage magnetic field from the hard magnetic film or a demagnetizing field generated when processing into a fine shape. Next, an example will be described.

As can be seen from FIG. 62, the ferromagnetic film 91 and the nonmagnetic film 9 having the spin-dependent scattering ability on the substrate 90.
2 and a ferromagnetic film 93 were formed. Ferromagnetic films 91, 9
The thickness of the non-magnetic film 3 and the non-magnetic film 92 was the same as in Example 32. An antiferromagnetic film 94 having a thickness of 2 to 50 nm was formed thereon, and an exchange bias was applied to the ferromagnetic film 93. further,
A hard magnetic film 95 made of CoPt and CoNi having a thickness of 10 to 50 nm was formed thereon. An electrode terminal 96 was formed on the hard magnetic film 95. All film formation was performed in a static magnetic field (x direction in the figure).

Then, a magnetic field of 400 to 800 kA / m was applied in the same direction as the exchange bias magnetic field direction by the antiferromagnetic film 94 to magnetize the hard magnetic film 95 in the x direction. As a result, a bias magnetic field was applied to the ferromagnetic film 91 in the minus x direction due to the leakage magnetic field from the edge of the hard magnetic film 95, and the magnetizations of the ferromagnetic films 91 and 93 were in an antiparallel state.
The bias magnetic field from the hard magnetic film 95 is also applied to the ferromagnetic film 93, but by setting the exchange bias force so that the exchange bias magnetic field from the antiferromagnetic film 94 becomes stronger, A magnetized state can be realized. In addition,
The hard magnetic film 95 and the antiferromagnetic film 94 need not be formed on the entire surface of the ferromagnetic film 93, but may be formed only on the edge portion (near the electrode terminal 96) of the ferromagnetic film 93.

It is to be noted that, in 95 of FIG. 62, a ferromagnetic film close to soft magnetism can be used instead of the hard magnetic film. In this case, the ferromagnetic films close to soft magnetism need to be laminated so that an exchange bias is applied from the antiferromagnetic film 94. When an exchange bias is applied to the ferromagnetic film 95, the magnetization of the ferromagnetic film 95 can be fixed in one direction.
In addition, by processing into a fine pattern shape indispensable for the magnetoresistive effect, it is possible to apply the exchange bias magnetic field applied to the ferromagnetic film 93 from the anti-ferromagnetic film 94 in a direction different by 180 °. At this time, by adjusting the thickness and saturation magnetization of the ferromagnetic film 95, a bias magnetic field having a desired strength is applied to the ferromagnetic film 9.
1 can be given.

By adjusting the resistivity and film thickness of the ferromagnetic film 95, a desired shunt shunt operating point bias can be applied. Here, in the ferromagnetic film 95, the antiferromagnetic film 9
Required for exchange coupling with anti-ferromagnetic film 94
A crystalline ferromagnetic film having the same crystal structure and lattice constant as the antiferromagnetic film 94 for epitaxial growth, such as a NiFe film, a CoFe film, a CoFeTa film, and a CoFeP film.
It is difficult to satisfy both the characteristics required for the magnetostatic coupling bias and the operating point bias (the resistivity is too low with the above crystalline film). Therefore, the ferromagnetic film 95 is composed of a magnetic film for exchange coupling (NiFe or CoFe-based ferromagnetic film or the like) in contact with the antiferromagnetic film 94 and a ferromagnetic film for bias (Co-based amorphous film, FeTaN, etc.). It is desirable that a crystal film or a carbonized microcrystalline film such as FeZrC) has a two-layer structure in which ferromagnetic exchange coupling is performed at the interface.

In the case of the structure shown in FIG. 62, the hard magnetic film 95
, The sense current from the electrode terminal 96 shunts so that ΔR /
It is inevitable that R decreases to some extent. This problem can be solved by the structure shown in FIGS.

That is, as shown in FIG. 63, the substrate 90
62, the hard magnetic film 95 is formed near both sides of the antiferromagnetic film 94. Electrode terminals 96 are formed on the inside at intervals corresponding to the track width. As a result, it is possible to prevent a sense current from flowing through the hard magnetic film 95, and to suppress a decrease in ΔR / R.

On the other hand, as shown in FIG. 64, a hard magnetic film 95 is first formed on a substrate 90, and a ferromagnetic film 91, a non-magnetic film 92, a ferromagnetic film 93, and an insulating film 97 are formed on the hard magnetic film 95. And an antiferromagnetic film 94 are sequentially formed, and electrode terminals 96 are further formed.
To form At this time, a predetermined exchange bias magnetic field is applied from the antiferromagnetic film 94 to the ferromagnetic film 93 by applying a static magnetic field during the film formation. After the film formation, the hard magnetic film 95 is magnetized in the same direction as the exchange bias direction. Also in this method, the ferromagnetic film 9
Bias magnetic fields in opposite directions can be applied to 1 and 93, and current can be prevented from flowing through the hard magnetic film 95. The insulating film 97 is composed of the hard magnetic film 95 and the ferromagnetic film 9.
There is also an effect of preventing an excessive bias magnetic field from being applied due to exchange coupling with 1.

Further, as shown in FIG. 65, a ferromagnetic film 91, a nonmagnetic film 92, a ferromagnetic film 93, and an antiferromagnetic film 94 are sequentially formed on the substrate 90. Next, the laminated film is finely processed into a predetermined shape. This fine processing is performed by forming a mask using a resist or the like and performing ion milling or the like. Thereafter, a hard magnetic film 95 is formed on the side of the ferromagnetic film 91 by a lift-off method using the remaining mask. Finally, the hard magnetic film 95 is magnetized in a direction opposite to the exchange bias applied to the ferromagnetic film 93. Also in this method, the ferromagnetic film 9
Bias magnetic fields in opposite directions can be applied to 1 and 93, and current can be prevented from flowing through the hard magnetic film 95.

(Embodiment 34) In the spin valve structure shown in FIG. 61, a 5 nm thick Cu underlayer containing 1 at% Cr and a 15 nm thick antiferromagnetic film 82 on a glass substrate 80.
FeMn film with a thickness of 1 nm and a ferromagnetic film 83a with a thickness of Ni of 1 nm
₈₀ Fe ₂₀ film, nonmagnetic film 87 having a thickness of 1.5 nm Cu film containing 1 at% Cr, ferromagnetic film 83b having a thickness of 6 nm Ni ₈₀ Fe ₂₀ film, and nonmagnetic film 84 having a thickness of 2.5 nm C
6 nm thick Ni ₈₀ Fe film as u film and ferromagnetic film 85b
₂₀ film, non-magnetic film 87 containing 1 at% Cr
5 nm Cu film, 1 nm thick Ni ₈₀ as ferromagnetic film 85a
The Fe ₂₀ film and the antiferromagnetic film 82 are made of F having a thickness of 15 nm.
The eMn film was sequentially formed.

These films were formed at once by a two-pole sputtering method in a static magnetic field using a permanent magnet without breaking the vacuum. The permanent magnet is not integrally attached to the substrate holder. At this time, the preliminary evacuation pressure is set to 1 × 10 ⁻⁴ Pa or less and the Ar gas pressure is set to 0.4 Pa. After the formation of the ferromagnetic film 83 is completed, the substrate holder is rotated by 180 ° and a permanent magnet is used. The direction of the bias magnetic field (about 4000 A / m) was inverted by 180 °. Thus, a laminated film having a spin-valve structure capable of realizing an antiparallel state of magnetization of both ferromagnetic films with no signal magnetic field was produced.

The resistance of the obtained laminated film was measured by the 4-terminal method. Specifically, a constant current of 1 mA is applied to the ferromagnetic films 83 and 85 in the easy axis direction, and the film width in the hard axis direction is set to 1
The voltage between 4 mm was measured as mm. A magnetic field was applied in the hard axis direction of the ferromagnetic films 83 and 85 by a Helmholtz coil. FIG. 67 shows the obtained resistance-magnetic field characteristics.

In FIG. 66, the resistance is the maximum magnetic field (16 k
A / m) is normalized to 1. When the magnetic field is zero, the magnetizations of the ferromagnetic films 83 and 85 are in an anti-parallel state, so that the resistance shows the maximum value. When a magnetic field is applied, the resistance drops sharply. In particular, the resistance shows a substantially constant value in a magnetic field of 2000 A / m or more. Resistance change rate of about 3.8% or less is 2000
It can be seen that it occurs in a small magnetic field range of A / m or less. Also, almost no hysteresis or noise is recognized in this resistance-magnetic field characteristic. That is, by using the laminated film having the spin valve structure, a magnetic head having extremely high sensitivity and low noise can be obtained.

Further, a spin valve type magnetoresistive effect element shown in FIG. 60 was produced, and the relationship between the thickness of the nonmagnetic layer 84 (Cu) and the resistance change rate was investigated. The results are shown in Table 6 below. An NiFe film having a thickness of 5 nm was used for the base film, an NiFe film having a thickness of 8 nm was used for the ferromagnetic films 83 and 85, and a FeMn film having a thickness of 10 nm was used for the antiferromagnetic film.

[0277]

[Table 6]

As can be seen from Table 6, the resistance change rate rapidly increased as the Cu thickness decreased, and a high resistance change rate of 9% was obtained when the Cu thickness was 1.2 nm. This is the ferromagnetic film 8
Since a relatively large antiparallel bias magnetic field of 50 kA / m is applied to each of the ferromagnetic film 3 and the ferromagnetic film 85, a stable antiferromagnetic magnetization arrangement can be realized even if the thickness of the nonmagnetic film 84 is reduced. is there. When the thickness of the nonmagnetic layer (Cu) is reduced to less than 2 nm, unlike the conventional spin-valve magnetoresistive element in which the antiparallel magnetization arrangement collapses and the resistance change rate sharply decreases, both the ferromagnetic films 83 and 84 are opposed to each other. By applying a bias magnetic field in the direction and reducing the thickness of the nonmagnetic film 84, the rate of resistance change can be greatly increased.

(Embodiment 35) Next, the case where the number of ferromagnetic films having the spin-dependent scattering ability is increased to three or more will be described.

As shown in FIG. 67, the base films 101 and F for controlling the orientation of the antiferromagnetic film 102 on the substrate 100.
An antiferromagnetic film 102 of e.g. eMn, NiO, PtMn having a thickness of 5 to 50 nm, a ferromagnetic film 103 of e.g. CoFe, Co, NiFe having a thickness of 1 to 20 nm, and a thickness of 1 to 10 nm composed of Cu, Au, etc. Non-magnetic film 104, thickness 1 to 20 nm
Ferromagnetic film 105, non-magnetic film 106 having a thickness of 1 to 10 nm,
A ferromagnetic film 107 having a thickness of 1 to 20 nm, and a thickness of 5 to 50 nm
A nm antiferromagnetic film 108 was formed. Here, the ferromagnetic film 1
The film thicknesses of 03, 105 and 107 may all be equal or different. Further, a protective film was formed thereon as necessary to form an electrode terminal 109. Note that the film was formed in a static magnetic field.

An exchange bias is applied from the antiferromagnetic films 102 and 108 to the ferromagnetic films 103 and 107 in one direction (x in the figure).
Direction). As a result, only the intermediate ferromagnetic film 105 has a high magnetic permeability, and the ferromagnetic films 103 and 107 have a low magnetic permeability, that is, a pinned magnetization. For fixing this magnetization, a hard magnetic film 95 as shown in FIG. 63 may be used instead of the antiferromagnetic film. The material of the ferromagnetic films 103 and 107 which are in contact with the antiferromagnetic films 102 and 108 has a low soft magnetism but a high resistance change rate.
Or CoFe, the material of the intermediate ferromagnetic film 105 has a low rate of change in resistance but has a good soft magnetism.
By using Fe, a high resistance change rate can be realized in a low magnetic field.

With such a structure, the intermediate ferromagnetic film 1
05 easily occurs in a low magnetic field, and the number of interfaces via the non-magnetic layer is twice as large as that of a conventional spin-valve structure film. A higher resistance change rate can be realized. In addition, since the ferromagnetic film that rotates by the signal magnetic field is located at the center of the laminated film, the disturbance of the magnetization of the ferromagnetic film due to the sense current magnetic field is slight, and stable signal detection becomes possible.
If the bias method using a hard magnetic film or a demagnetizing field as described in Embodiment 33 is used together, the angle between the magnetizations of the ferromagnetic films 103 and 107 and the intermediate ferromagnetic film 105 is made antiparallel with a signal magnetic field of 0. Can be As a result, with the various effects described in the thirty-second embodiment, it is possible to obtain a magnetoresistive element with higher sensitivity and lower noise.

(Example 36) FIG. 68 shows a laminated film in which the number of ferromagnetic films having the spin-dependent scattering ability is increased to four.

The four layers of ferromagnetic films 112, 114, 116 and 118 and the antiferromagnetic film 1 which are laminated on the substrate 100 with the antiferromagnetic film 111 and the nonmagnetic layers 113, 115 and 117 interposed therebetween.
19 were sequentially formed, and the electrode terminals 109 were formed thereon so that the sense current flowed in the same direction as the signal magnetic field. As necessary, a base film for controlling the orientation is formed below the antiferromagnetic film 111, and a protective film is formed above the antiferromagnetic film 119. The material and thickness of each film were the same as those shown in FIG.

At least during the film formation of the ferromagnetic film 112, a static magnetic field is applied in the x direction (track width direction) in the figure, while the static magnetic field direction is reversed by 180 ° during the subsequent film formation, and at least a repulsive force is applied. During the formation of the magnetic film 119, a static magnetic field was applied in the negative x direction in the figure. Due to the static magnetic field during the film formation,
The magnetization is fixed by the exchange bias magnetic field in the x direction in the ferromagnetic film 112 and in the minus x direction in the ferromagnetic film 118. Further, in this configuration, if the track width is narrow, the widths of the ferromagnetic films 112, 114, 116, and 118 are also narrowed, so that a strong demagnetizing field is generated in that direction. Due to this demagnetizing field, the intermediate ferromagnetic film 114 not in contact with the antiferromagnetic film
And 116 are antiparallel to the magnetizations of ferromagnetic films 112 and 118, respectively. That is, when the signal magnetic field is 0, the adjacent magnetizations of the four ferromagnetic films are oriented antiparallel to each other.

When the demagnetizing field to the intermediate ferromagnetic films 114 and 116 is insufficient, the magnetic field generated by the sense current is in the negative x direction in the ferromagnetic films 112 and 114.
In the ferromagnetic films 116 and 118, it is desirable to apply a sense current in the y direction in the figure so as to apply in the x direction. here,
If the exchange bias magnetic field from the antiferromagnetic film is set to be larger than the sense current magnetic field, the ferromagnetic films 112 and 1
18 can be fixed in the exchange bias direction from the antiferromagnetic film without being disturbed by the current magnetic field.

With such a structure, the magnetization directions of the four layers of ferromagnetic films can be antiferromagnetically aligned at the signal magnetic field of zero. Therefore, ΔR /
R increases. In addition, since the magnetization of each layer can be rotated by slightly applying a signal magnetic field, a highly sensitive magnetoresistive element using spin-dependent scattering can be realized.

(Example 37) Next, the magnetization of a part of the ferromagnetic film having the spin-dependent scattering ability is fixed, and the magnetizations of the remaining ferromagnetic films are arranged in the signal magnetic field 0 in a direction different from the signal magnetic field direction. The case will be described.

FIG. 69 shows a laminated film in which the directions of the sense current and the signal magnetic field are orthogonal to each other. The nonmagnetic film 12 is formed on the substrate 120.
Ferromagnetic film 1 having spin-dependent scattering ability with intervening 2
A laminated film 21 and 123 and an antiferromagnetic film 124 were sequentially formed. The material and thickness of each film were the same as those shown in FIG. If necessary, an electrode terminal 125 was formed after a protective film was formed on the antiferromagnetic film 124.

Here, at least during the formation of the ferromagnetic film 121, a static magnetic field is applied in the direction of the bisector of the x axis and the y axis in the figure, while at least the antiferromagnetic film 124 is formed. In some cases, the direction of the static magnetic field was rotated by 45 ° with respect to the former direction (y direction in the drawing). As a result, the ferromagnetic film 121
Is applied in the x direction of the static magnetic field, and the ferromagnetic film 12
The magnetization of No. 3 was fixed in the signal magnetic field direction by the bias magnetic field from the antiferromagnetic film 124. According to such a configuration,
When the signal magnetic field is 0, the angle between the magnetizations of the two ferromagnetic films becomes 45 °. When the signal magnetic field is applied to the magnetization fixed direction of the ferromagnetic film 123, the magnetization directions of the two ferromagnetic films become ferromagnetic. When the resistance decreases and a signal magnetic field is applied in a direction different from the magnetization fixed direction by 180 °, the resistance increases because the magnetization directions of the two ferromagnetic films have an antiferromagnetic arrangement. Therefore,
The operating point bias, which is required for the conventional magnetoresistive element to realize the linear response, is not required. In this method, the magnetization of the ferromagnetic film 121 is easily inclined in the y direction at the signal magnetic field of 0 due to the ferromagnetic coupling between the ferromagnetic films 121 and 123, and the reproduction signal is easily distorted when a large signal magnetic field is applied. Tend. This is so that the current magnetic field generated by the sense current is applied in the ferromagnetic film 121 in a direction different from the ferromagnetic coupling direction by 180 °, that is, the magnetic field due to the ferromagnetic coupling and the current magnetic field are cancelled. This can be avoided by determining the direction in which the sense current flows.

However, when films having an anisotropic magnetoresistive effect are used as the ferromagnetic films 121 and 123, conversely, the magnetization M of the ferromagnetic film 121 is changed by the magnetic field due to this ferromagnetic coupling. If the magnetization is tilted in the M direction, the resistance change due to the magnetic anisotropy and the spin scattering will be superimposed (because the current direction is the x direction), so that the sensitivity can be expected to be improved. Actually, it is necessary to adjust the magnetization direction of the ferromagnetic film 121 by means such as the current direction according to the situation where the magnetoresistance effect element is used.

By the way, in the thirty-seventh embodiment, it is necessary to apply the longitudinal bias magnetic field (bias magnetic field in the direction of the bisector of the x-axis and the y-axis in the figure) necessary for suppressing Barkhausen noise. For this purpose, an antiferromagnetic film as shown in Example 32 is disposed on the substrate side of the ferromagnetic film 121 and exchange-coupled. Alternatively, as shown in FIG. 70A, a ferromagnetic film 126 having good soft magnetism (Hc is smaller than the exchange bias magnetic field _HUA ) is laminated on the antiferromagnetic film 124 to a certain extent. During the lamination of the ferromagnetic film 126, the direction of the bias magnetic field during the film formation is reversed by approximately 135 °.
There is a method of applying an exchange bias magnetic field from the ferromagnetic film 121 to the ferromagnetic film 121. In this case, since the film serving as the spin-dependent scattering unit also serves as a base film, an exchange bias can be easily applied to the ferromagnetic film 126 formed on the antiferromagnetic film 124. As a result, a longitudinal bias magnetic field can be applied to the ferromagnetic film 121 by a magnetostatic coupling magnetic field (a demagnetizing field) generated when actually processing into a fine pattern suitable for a reproducing head, so that Barkhausen noise can be suppressed. .

In the embodiment shown in FIG. 70A, the antiferromagnetic film 1 is used.
Since the exchange bias direction differs on both sides of the film surface of No. 24,
The direction of the bias magnetic field may be unstable. This is because, as shown in FIG. 70 (B), the extremely thin intermediate film 1 which weakens magnetic coupling with the antiferromagnetic film 124 in between but does not inhibit crystal growth.
24b (fcc phase film such as Cu) through the antiferromagnetic film 12
4a and 124c can be avoided. At this time, as described in the thirty-second embodiment, the antiferromagnetic films 124a and 124c are preferably made of materials having different Neel points or blocking temperatures in order to control the direction of the exchange bias magnetic field by the heat treatment. Further, the ferromagnetic film 12
6 is thick and Bs is not high, a desired longitudinal bias magnetic field cannot be applied to the ferromagnetic film 121.
6, the resistivity of the ferromagnetic film is desirably high. Specifically, it is desirable to use a Co-based or Fe-based amorphous film or a nitrided or carbonized microcrystalline film. However, since such a film is hardly exchange-coupled with an antiferromagnetic film such as FeMn, the antiferromagnetic film 124a
A ferromagnetic film 124b, such as NiFe or CoFeTa, which is easily exchange-coupled, is laminated on a portion in contact with, and a high-resistance amorphous high-Bs ferromagnetic film 126a is laminated thereon so as to perform ferromagnetic exchange coupling. It is desirable.

(Example 38) FIG. 70C shows a laminated film in which the directions of the sense current and the signal magnetic field are parallel to each other. The configuration is the same as that of FIG. 69 except that the direction in which the sense current flows is different, the magnetization of the ferromagnetic film 121 is applied in the x direction in the figure, and the longitudinal direction of the film is rotated by 90 °. In this configuration, when the signal magnetic field is 0, the angle between the magnetizations of the two ferromagnetic films becomes 90 °, and when the signal magnetic field is applied to the magnetization fixed direction of the ferromagnetic film 123, the magnetizations of the two ferromagnetic films become ferromagnetically aligned. , The resistance decreases. Conversely, when a signal magnetic field is applied in a direction different from the magnetization fixed direction by 180 °, the resistance increases because the magnetizations of both ferromagnetic films are arranged in an antiferromagnetic arrangement. Therefore,
No more operating point bias is required. In this configuration,
The current magnetic field due to the sense current is in the easy axis direction of the ferromagnetic film 121, and this magnetic field has the effect of suppressing Barkhausen noise.

Furthermore, in Example 38, the ferromagnetic film 123 was used.
Ferromagnetic film 12
It should be added that the magnetization of No. 1 is easily inclined in the y direction.
As described in detail in the thirty-seventh embodiment, the ferromagnetic coupling magnetic field reduces the signal magnetic field dynamic range, but has the advantage of superimposing the anisotropic magnetoresistance effect. Since the current magnetic field is applied to the ferromagnetic film 121, the ferromagnetic film 1
It is not necessary that the 21 easy axes be in the x-direction.

When the Barkhausen noise suppressing effect is insufficient, the magnetization fixed direction of the ferromagnetic film 123 is deviated from the signal magnetic field direction, so that a magnetostatic coupling magnetic field is generated in the x direction in the figure to generate stronger Barkhausen noise. A suppressing magnetic field can be applied.

(Example 39) FIG. 71 shows a laminated film in which three ferromagnetic films having spin-dependent scattering ability are formed. FIG. 71 shows a case where the sense current and the signal magnetic field are orthogonal. Ferromagnetic films 132, 134, 13 having a spin-dependent scattering ability with an antiferromagnetic film 131 and nonmagnetic films 133 and 135 interposed on a substrate 130 in a static magnetic field.
The laminated film of No. 6 and the antiferromagnetic film 137 were sequentially formed. An electrode terminal 138 was formed thereon.

Here, the direction of the static magnetic field is at least the same direction during the formation of the ferromagnetic film 132 and the antiferromagnetic film 137 (the y direction in the figure), and is 4 when the ferromagnetic film 134 is formed.
5 ° angle direction (direction of bisector of x axis and y axis in the figure)
And As a result, the magnetizations of the ferromagnetic films 132 and 136 are fixed in the y direction in the drawing, the magnetization of the ferromagnetic film 134 maintains a high magnetic permeability, and at a magnetic field of 0, the vicinity of the bisector of the x axis and the y axis in the drawing is shown. Turn to. Therefore, even in this configuration, when the magnetic field is 0, the angle between the magnetizations of the two ferromagnetic films is approximately 45 °, and when the signal magnetic field is applied to the magnetization fixed direction of the ferromagnetic film 136, the magnetization directions of the two ferromagnetic films become ferromagnetic. The resistance is reduced due to the natural arrangement,
Conversely, when a signal magnetic field is applied in a direction 180 ° different from the magnetization fixed direction, the resistance increases because the magnetization directions of both ferromagnetic films become antiferromagnetic. That is, the operating point bias becomes unnecessary. In this configuration, the number of interfaces is doubled, so that the sensitivity is also improved.

(Embodiment 40) The resistance-magnetic field characteristic of the laminated film of the magnetoresistive effect element of the method shown in Embodiment 38 will be described.

In FIG. 70C, a sapphire C-plane substrate is used as the substrate 120, a Co ₉₀ Fe ₁₀ film having a thickness of 6 nm and a Pd base film having a thickness of 5 nm is used as the ferromagnetic film 121, and the nonmagnetic film 122 is used. A 3 nm thick Cu film is used as
A 4 nm-thick Co ₉₀ Fe ₁₀ film is used as the ferromagnetic film 123, a 15 nm-thick FeMn film is used as the antiferromagnetic film 124, and a 5 nm-thick Pn film is formed thereon as a protective film.
A d film was formed.

This laminated film was collectively formed by a two-pole sputtering method while maintaining a vacuum. During the film formation, a static magnetic field is applied by a permanent magnet, and after the film formation of the ferromagnetic film 121 is completed, the direction of the static magnetic field is reversed by 90 ° to form an angle between the easy axes of the ferromagnetic films 121 and 123. Was set to 90 °. In addition, the preliminary exhaust of sputtering is 1 × 10 ⁻⁴ Pa or less,
The sputtering gas pressure was 0.4 Pa.

The resistance-magnetic field characteristics of this laminated film are shown in Example 33.
It measured similarly to. FIG. 72 shows the resistance-magnetic field characteristics in the hard axis direction. In FIG. 72, the resistance in the ferromagnetic magnetization arrangement is normalized as one. As can be seen from FIG. 72, a change in the resistance magnetic field with good linearity is obtained at a signal magnetic field of zero. This shows that the operating point bias is unnecessary.

(Example 41) In this example, two or more layers of another ferromagnetic film or antiferromagnetic film are laminated on both ferromagnetic films of the spin-dependent scattering unit composed of ferromagnetic film / nonmagnetic film / ferromagnetic film. Then, an embodiment of a magnetoresistive effect element in which both bias magnetic fields generated at that time are substantially orthogonal to each other will be described.

FIG. 73 shows a high-Hk ferromagnetic film (for example, Hk to 5 kA) having a hard ferromagnetic film such as CoPt and a uniaxial magnetic anisotropic magnetic field Hk larger than those of the spin-dependent scattering unit on the substrate 120. / M CoFeRe film, etc.) or N
a first bias film 121a for applying a bias magnetic field made of an antiferromagnetic film such as iO, a spin-dependent scattering unit (a ferromagnetic film 121, a nonmagnetic film 122, a ferromagnetic film 12
3) shows a multilayer film in which a second bias film 124 for applying a bias magnetic field made of an antiferromagnetic film such as FeMn is sequentially stacked. The first bias film 121a of this multilayer film
, A bias magnetic field is mainly applied to the ferromagnetic film 121 by exchange coupling through the lamination interface.
On the other hand, the bias magnetic field generated from the second bias film 124 is mainly due to exchange coupling through the lamination interface.
Join 23. The first and second bias magnetic fields are applied so as to satisfy a directional relationship that is substantially orthogonal. Further, the second bias magnetic field has a strong value such that the magnetization of the ferromagnetic film 123 cannot be substantially moved by the signal magnetic field (10 kA).
/ M or more is desirable).

On the other hand, the first bias magnetic field strength is set to such a level that the magnetization of the ferromagnetic film 121 can be rotated by the signal magnetic field and Barkhausen noise can be suppressed. Specifically, when an antiferromagnetic film is used for the first bias film,
It is desirable that the bias magnetic field between the bias film 121a and the ferromagnetic film 121 be 5 kA / m or less. When a ferromagnetic film is used for the first bias film, the magnetization direction of the bias film 121a is maintained in a fixed direction by a certain means to form a single magnetic domain, and the bias film 121a and the ferromagnetic film 121 are strongly exchange-coupled. When integrated, the bias film 12 is generated by the signal magnetic field.
Since the ferromagnetic film 1a and the ferromagnetic film 121 can be rotated in substantially the same manner and the ferromagnetic film 121a has a single magnetic domain, the ferromagnetic film 121 also has a single magnetic domain, so that Barkhausen noise can be removed. Alternatively, for example, another layer is inserted into the interface to form the bias film 121a.
Exchange coupling between the ferromagnetic film 121 and the ferromagnetic film 121 to 5 kA / m or less. In this case, since only the ferromagnetic film 121 is rotated by the signal magnetic field, it is preferable to suppress the magnetic permeability of the bias film 121a to make the magnetization hard to move. As a means for suppressing the magnetic permeability, there is an improvement in Hk, an improvement in coercive force, or application of a unidirectional bias magnetic field to the bias film 121a by some means.

Here, as a means for making the ferromagnetic film 121a into a single magnetic domain, as shown in FIG.
a is longer than the spin valve unit and the bias film 1
A new antiferromagnetic film or hard film 121 is provided at the edge of 21a.
It is possible to stack b.

When the magnetoresistive effect element having the above structure is manufactured, the magnetization direction of the ferromagnetic film 123 is fixed and the ferromagnetic film 12 is fixed.
Since the magnetization of No. 1 changes in accordance with the signal magnetic field, a high-sensitivity magnetoresistive element having good linearity with a signal magnetic field of 0 to 0 can be obtained as in the embodiment shown in FIG. 69, and the signal magnetic field is detected. Since the domain wall of the ferromagnetic film 121 can also be removed, a high-sensitivity, noise-free signal magnetic field reproduction can be performed without an operating point bias.

Here, the direction of the easy axis of magnetization of the ferromagnetic film 121 may be applied in the direction orthogonal to the bias magnetic field direction.
It is particularly desirable when a Co-based ferromagnetic film having a large magnetic anisotropy is used for 121. Then, since the saturation magnetic field corresponding to the anisotropic magnetic field and the bias magnetic field can be canceled out, Hs can be greatly reduced. Therefore, the slope of the saturation magnetic field-resistance characteristic shown in FIG. Compared to the case where the axes of easy magnetization of the ferromagnetic films 121 are in the same direction, it is possible to detect the signal magnetic field with higher sensitivity. To change the direction of the bias magnetic field and the direction of the easy axis of the ferromagnetic film, the direction of the magnetic field application during the formation of the bias film 121a and the direction of the ferromagnetic film 1
For example, there is a method of changing the direction in which the magnetic field is applied during the film formation of No.

(Example 42) As shown in FIG. 75, a Cr base film 141 having a thickness of 20 nm for controlling the orientation of a high coercive force film on a supporting substrate 140, and a thickness of 8 nm made of Co or the like.
A high coercive force film 142, a non-magnetic film 143 having a thickness of 3 nm made of Cu, and a ferromagnetic film 144 made of NiFe having a thickness of 4.6 nm are sequentially formed, and an electrode terminal 145 is further formed thereon. A magnetoresistive effect element having a spin valve structure was produced. The deposition of the laminated film was performed by ultrahigh vacuum E gun vapor deposition. The substrate temperature at this time is about 100 ° C.,
The inside of the vacuum chamber was evacuated to 1 × 10 ⁻⁸ Pa or less.

Co / C when the substrate temperature is about 100 ° C.
The X-ray diffraction pattern of the r film was examined. The result is shown in FIG. As shown in FIG. 76, this film is made of Cr (20
0) is highly oriented, and (110) is also highly oriented in the Co film using this Cr film as a base film. In addition, Co (110)
The full width at half maximum of the rocking curve of the peak was about 3 °.

Next, a film is formed at a substrate temperature of about 100.degree.
77 shows the RH curve in the hard axis direction of the laminated film having the structure of NiFe / Cu / Co / Cr / substrate shown in FIG. R-
The H-curve is processed into a 2mm x 6μm pattern using a normal resist process and ion milling.
It was created based on the values measured by the terminal method. At this time, the easy axis was set in the pattern longitudinal direction, and the magnetic field was applied in the pattern width direction.

As shown in FIG. 77, when the applied magnetic field is ± 80 Oe, the resistance change rate is about 6.5%, and the saturation magnetic field is about 3.
It became 6 kA / m.

In this structure, Hc of the high coercive force film is about 8 kA.
/ M, there is no problem when the magnetic field from the medium is less than 8 kA / m. However, in a structure in which the head is close to the medium, that is, a structure in which the magnetic field from the medium is 8 kA / m or more. Not suitable. Therefore, the laminated film was formed in the same structure and thickness as in FIG. 75, at a substrate temperature of about 200 ° C., and in a magnetic field of about 8 kA / m.

Co / C when the substrate temperature is about 200 ° C.
The X-ray diffraction pattern of r was almost the same as FIG. In addition, this laminated film also had a rocking curve half width of the Co (110) peak of about 3 °. Furthermore, when measured with a pole figure, a deviation of the hexagonal C axis was observed in the direction of the magnetic field. Therefore, single-crystal-like Co was obtained as compared with a laminated film formed at a substrate temperature of 100 ° C. in a non-magnetic field.

Next, R in the direction of the hard axis of the laminated film having the same structure as that shown in FIG. 75 formed in a magnetic field at a substrate temperature of about 200 ° C.
FIG. 78 shows the −H curve. The RH curve was prepared based on values measured by a four-terminal method by processing the laminated film into a pattern of 2 mm × 6 μm in the same manner as described above. At this time, the easy axis (C
The direction of the axis was the longitudinal direction of the pattern, and the magnetic field was applied in the pattern width direction.

As shown in FIG. 78, the external magnetic field ± 1.6 k
Even in the case of A / m, the magnetization of the high coercive force film hardly moved by the applied magnetic field, and the saturation magnetic field of the NiFe film could be kept low at about 2.8 kA / m. Further, the resistance change rate was also about 7.5%.

The laminated film having the above structure has an external magnetic field of 1.6 kA.
/ M, since the magnetization of the high coercivity film is stable, NiF
A pattern was prepared in which the easy axis of the e film was the width direction and the C axis of Co was substantially the longitudinal direction. This configuration eliminates the need for operating point bias. At this time, a magnetic field was applied in the longitudinal direction of the pattern, and the RH curve at that time was measured. In addition,
The pattern shape was 2 mm × 6 μm as described above. FIG. 79 shows the result. As can be seen from FIG. 79, a good RH curve without hysteresis was obtained, and Hk also showed a low value of about 1.6 kA / m.

Although the Co film is used as the high coercive force film here, a CoNi film or a CoCr film may be used. Further, a W film or the like may be used as the underlayer film in addition to the Cr film, and an additive element may be added to these Cr and W bases. This underlayer can be applied to a so-called hard film underlayer throughout the present invention. Thereby, the C axis can be present in the film surface of the hard magnetic film (the C axis is aligned in a specific direction). Therefore,
When the hard magnetic film is fixed, it is possible to prevent the ferromagnetic film formed thereon from being fixed.

For reference, the MH curve of the laminated film having no underlying film is shown in FIG. It can be seen that a leakage magnetic field is generated from the perpendicular component of the magnetization of Co, deteriorating the soft magnetic characteristics of the NiFe film. This is because some NiFe and C
It is considered that the magnetization of o is integrated.

(Example 43) As shown in Example 42,
Since the high coercive force film formed at a substrate temperature of about 200 ° C. is a single crystal-like film and has low resistance, the mean free path of electrons can be made sufficiently longer than the thickness of the high coercive force film. Therefore, FIG.
1, the high coercive force film 142 and the ferromagnetic film 144 are made of Cu.
The layers were stacked with the nonmagnetic film 143 interposed therebetween. The resistance change rate of this laminated film showed a high value of about 15%. In order to manufacture a laminated film having such a structure, the high coercive force film 1 of the first layer is used.
It is desirable to provide a base film to control the orientation of 42. Further, in this embodiment, as a base film, C having a thickness of 20 nm is used.
The r film 141 was used.

(Example 44) Next, the case where the high coercive force control film for orientation control is used as the bias film in Example 34 will be described.

In this example, as shown in FIG. 82, a magnetoresistive effect element having a spin valve structure was formed on a high coercive force controlling film 142 with a magnetic insulating layer 146 interposed therebetween. As described above, by using the orientation control high coercive force film 142, the high coercive force film 142 and the NiFe film 1 are formed at the film end portions.
44 is magnetostatically coupled, and the domain wall at the end of the NiFe film, which causes Barkhausen noise, can be fixed. Furthermore, since the orientation control high coercive force film is used, the influence of the high coercive force film on the NiFe film, for example, the leakage magnetic field inside the film can be avoided, and a good device can be manufactured without deteriorating the soft magnetic characteristics of the NiFe film. it can. Here, an antiferromagnetic film or the like may be used as the exchange bias film having the spin valve structure.

[0323]

As described above, the magnetoresistance effect element of the present invention can simultaneously exhibit a high rate of change in resistance and excellent soft magnetic properties, and its industrial value is large.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a magnetoresistive element (spin valve structure) according to a first embodiment of the present invention.

FIG. 2 is a graph showing an external magnetic field dependency of a resistance change rate of the magnetoresistive element shown in FIG.

3A and 3B are graphs showing magnetization curves of the magnetoresistive effect element shown in FIG. 1.

FIG. 4 is a sectional view showing an example of the magnetoresistance effect element (artificial lattice film) according to the first invention of the present invention.

5 is a graph showing the external magnetic field dependence of the rate of change in resistance of the magnetoresistive element shown in FIG.

FIG. 6 is a graph showing the film thickness dependence of coercive force when a Cu ₉₀ Fe ₁₀ film has a Cu underlayer.

FIG. 7 is a graph showing the dependence of the coercive force on the film thickness when there is no Cu underlayer of the Co ₉₀ Fe ₁₀ film.

FIG. 8 is a sectional view showing a magnetoresistive element (spin valve structure) according to the first invention of the present invention.

FIG. 9A is a diagram showing θ-2θ on the sapphire substrate C surface.
Scan X-ray diffraction curve, (B) shows θ-2θ scan X-ray diffraction curve on R surface of sapphire substrate.

FIG. 10: Co ₉₀ Fe ₁₀ film / Cu film / sapphire substrate C
Rocking curve for the densest surface peak in the surface.

FIG. 11 is a graph showing the dependence of the coercive force of the Co ₉₀ Fe ₁₀ film on the half width of the rocking curve in the close-packed surface reflection.

FIG. 12 is a graph showing the dependence of the coercive force on the Al concentration x in the (Co ₉₀ Fe ₁₀ ) _1-x Al _x film / Cu film.

FIG. 13 is a graph showing the dependence of the coercive force of the Co ₉₀ Fe ₁₀ film / Cu film on the close-packed surface reflection intensity.

[14] _{(Co 90 Fe 10) 1-} x Ta x film / Cu film graph showing the Ta concentration x dependency of the coercive force in the.

FIG. 15 is a sectional view showing a magnetoresistive element (spin valve structure) according to the first invention of the present invention.

FIG. 16 is a sectional view showing a magnetoresistive element according to a third invention of the present invention.

17 is an MH curve in the easy axis direction of the magnetoresistive element shown in FIG.

18 is an MH curve of the magnetoresistive element shown in FIG. 16 in the hard axis direction.

19 is an RH curve of the magnetoresistive element shown in FIG.

FIG. 20 is an MH curve in the easy axis direction of a magnetoresistive element without a high-resistance amorphous layer.

FIG. 21 is an MH curve in a hard axis direction of a magnetoresistive element without a high-resistance amorphous layer.

FIG. 22 is a sectional view showing a magnetoresistance effect element according to a third invention of the present invention.

FIGS. 23A to 23C are cross-sectional views showing a manufacturing process of another example of the magnetoresistance effect element according to the third invention of the present invention.

FIG. 24 is a perspective view showing another example of the magnetoresistance effect element according to the third invention of the present invention.

FIG. 25 is a sectional view showing an example of a magnetoresistive element according to a fourth aspect of the present invention.

26 shows △ ρ in the magnetoresistance effect element shown in FIG.
5 is a graph showing the relationship between / ρ ₀ and d _CoFe .

FIG. 27 is a sectional view showing a magnetoresistance effect element according to a fifth aspect of the present invention.

FIG. 28 is a sectional view showing a magnetoresistance effect element according to a fifth invention of the present invention.

FIG. 29 is a graph showing the dependence of the coercive force on the thickness of the ferromagnetic film in the magnetoresistance effect element according to the sixth aspect of the present invention.

FIG. 30 is a graph showing the dependence of the coercive force on the thickness of the ferromagnetic film in the magnetoresistance effect element according to the sixth aspect of the present invention.

FIG. 31 is a magnetization curve of a ferromagnetic film of a magnetoresistive element according to a sixth aspect of the present invention.

FIG. 32 is a graph showing the stacking cycle dependence of the magnetoresistance effect element according to the seventh aspect of the present invention.

FIG. 33 is a graph showing a relationship between a saturation magnetic field Hs and a Cu film thickness in a ferromagnetic film of a magnetoresistive element according to a sixth invention of the present invention.

FIG. 34 is a magnetization curve of a ferromagnetic film of a magnetoresistive element according to a seventh aspect of the present invention.

FIG. 35 is a sectional view showing a magnetoresistive element according to a seventh invention of the present invention.

FIG. 36 is a sectional view showing an interface state between Cu and CoFe in the seventh invention.

FIG. 37 is a magnetization curve of the magnetoresistance effect element shown in FIG.

FIG. 38 is a graph showing the resistance change characteristics of the magnetoresistance effect element shown in FIG.

FIG. 39 is a magnetization curve of a conventional magnetoresistance effect element.

FIG. 40 is a graph showing resistance change characteristics of a conventional magnetoresistance effect element.

41 (A) and (B) are magnetization curves of a ferromagnetic film having a Cu underlayer of the magnetoresistive element of the seventh invention of the present invention.

FIG. 42 shows C of the magnetoresistance effect element of the seventh invention of the present invention.
9 is a graph showing resistance change characteristics of a ferromagnetic film having a u underlayer.

FIG. 43 is a sectional view showing a magnetoresistance effect element according to a fourth invention of the present invention.

FIG. 44 is a magnetization curve of the magnetoresistance effect element shown in FIG. 43.

FIG. 45 is a graph showing the resistance change characteristics of the magnetoresistance effect element shown in FIG. 43.

FIG. 46 is a schematic view for explaining fluctuation in a film.

FIG. 47A shows Co ₉₀ F on a MgO (110) surface substrate
X-ray diffraction curve of small angle reflection of e ₁₀ / Cu artificial lattice film,
(B) shows Co ₉₀ Fe ₁₀ / Cu on MgO (110) plane substrate
X-ray diffraction curve of medium angle reflection of the artificial lattice film.

48A shows a rocking curve measured from the [110] axis direction regarding the fcc (220) reflection in FIG. 47, and FIG. 48B shows a rocking curve measured from the [100] axis direction regarding the fcc (220) reflection in FIG. 47. curve.

FIG. 49A is a schematic diagram showing an in-plane distribution of a normal line of a crystal orientation surface due to fluctuation of the crystal orientation surface, and FIG. 49B is a schematic diagram showing a sense current direction dependency of a resistance change rate.

FIG. 50 (A) shows Cu 5.5 nm / (Cu 1.1 nm / C)
oFe 1 nm) ₁₆ The magnetization curve in the direction of the external magnetic field [100] of the artificial lattice film, (B) is Cu 5.5 nm / (Cu 1.1 nm /
(CoFe 1 nm) A magnetization curve in the direction of the external magnetic field [110] axis of the ₁₆ artificial lattice film.

FIG. 51 shows Co ₉₀ F on a MgO (110) plane substrate
6 is a graph showing the bias voltage dependence of the rate of change of resistance of the e ₁₀ / Cu laminated film.

FIG. 52: Co ₉₀ Fe ₁₀ oriented in the fcc phase (111) plane
FIG. 3 is a conceptual diagram in a case where stacking faults are introduced into a / Cu stacked film.

FIG. 53: Co ₉₀ Fe ₁₀ oriented in the fcc phase (111) plane
FIG. 3 is a conceptual diagram showing an atomic arrangement when a stacking fault is introduced into a / Cu stacked film.

FIG. 54: Co ₉₀ Fe ₁₀ oriented in the fcc phase (111) plane
FIG. 3 is a conceptual diagram showing an atomic arrangement in the case where twin defects are introduced into a / Cu laminated film.

55 is a schematic diagram showing the sense current direction dependence of the resistance change rate in the state shown in FIG. 54.

FIG. 56 is a graph showing the substrate bias dependence of the rate of change in resistance of a Co ₉₀ Fe ₁₀ / Cu artificial lattice film on a glass substrate.

FIG. 57 is a graph showing the bias dependency of the long-period structure reflection intensity of the Co ₉₀ Fe ₁₀ / Cu artificial lattice film on a glass substrate.

FIG. 58 is a graph showing bias dependence of the reflection intensity of the fcc phase (111) surface of a Co ₉₀ Fe ₁₀ / Cu artificial lattice film on a glass substrate.

FIG. 59 is a graph showing the bias dependence of the coercive force of a Co ₉₀ Fe ₁₀ / Cu artificial lattice film on a glass substrate.

FIG. 60 is a perspective view showing a magnetoresistance effect element according to an eighth aspect of the present invention.

FIG. 61 is a perspective view showing a magnetoresistance effect element according to an eighth aspect of the present invention.

FIG. 62 is a perspective view showing a magnetoresistance effect element according to an eighth aspect of the present invention.

FIG. 63 is a perspective view showing a magnetoresistive element according to an eighth aspect of the present invention.

FIG. 64 is a perspective view showing a magnetoresistance effect element according to an eighth aspect of the present invention.

FIG. 65 is a perspective view showing a magnetoresistance effect element according to an eighth aspect of the present invention.

FIG. 66 is a graph showing the resistance change characteristics of the magnetoresistive element according to the eighth aspect of the present invention.

FIG. 67 is a perspective view showing a magnetoresistive element according to a twelfth aspect of the present invention.

FIG. 68 is a perspective view showing a magnetoresistive element according to a twelfth aspect of the present invention.

FIG. 69 is a perspective view showing a magnetoresistive element according to a tenth aspect of the present invention.

70 (A) to 70 (C) are perspective views showing a magnetoresistive element according to a tenth aspect of the present invention.

FIG. 71 is a perspective view showing a magnetoresistance effect element according to a tenth aspect of the present invention.

FIG. 72 is a graph showing the resistance change characteristics of the laminated film of the magnetoresistive element according to the tenth aspect of the present invention.

FIG. 73 is a perspective view showing a magnetoresistive element according to a twelfth aspect of the present invention;

FIG. 74 is a sectional view showing a magnetoresistive element according to a twelfth aspect of the present invention;

FIG. 75 is a sectional view showing a magnetoresistive element according to a thirteenth aspect of the present invention;

FIG. 76 is an X-ray diffraction pattern of a Co / Cr laminated film.

FIG. 77 shows a first example of the present invention formed at a substrate temperature of about 100 ° C.
The RH curve of the laminated film of the invention of FIG.

FIG. 78 shows a first example of the present invention formed at a substrate temperature of about 200 ° C.
The RH curve of the laminated film of the invention of FIG.

FIG. 79 is an RH curve of the laminated film of the thirteenth invention of the present invention when the pattern width direction is set as an easy axis.

FIG. 80 shows an RH curve of a laminated film of the thirteenth invention of the present invention when no base film is provided.

FIG. 81 is a sectional view showing a magnetoresistive element according to a thirteenth aspect of the present invention;

FIG. 82 is a sectional view showing a magnetoresistive element according to a thirteenth aspect of the present invention;

FIG. 83 is a perspective view showing a conventional magnetoresistance effect element.

FIG. 84 is an RH curve of a conventional magnetoresistance effect element.

[Explanation of symbols]

10, 20: sapphire substrate, 11, 21, 71: Co
₉₀ Fe ₁₀ film, 12, 22, 23, 70 ... Cu film, 13 ...
FeMn film, 14 ... Ti film, 15, 24 ... Cu lead,
26 ... Ni oxide film, 30, 41, 140 ... Support substrate,
31, 46 ... High-resistance amorphous layer, 32, 44, 8
3,85,91,93,103,105,107,11
2,114,116,118,121,123,13
2,134,136,144 ... ferromagnetic film, 33,45,
143 intermediate layer, 34 exchange bias layer, 35, 47
Lead, 42: CoPtCr film, 43: Resist, 5
0, 80, 90, 100, 120, 130... Substrate, 51
... Ferromagnetic laminated unit, 52, 84, 87, 88, 92, 1
04, 106, 113, 115, 117, 122, 13
3,135,163 ... nonmagnetic film, 53,82,94,1
02, 108, 111, 119, 124, 131, 13
7, 165: antiferromagnetic film, 54, 166: protective film, 5
5, 62, 86, 96, 109, 125, 145: electrode terminal, 60: MgO substrate, 61: laminated film, 81, 10
1, 141: base film, 95: hard magnetic film, 97: insulating film, 142: high coercive force film, 146: magnetic insulating layer, 16
0: thermally oxidized Si substrate, 161: high-resistance ferromagnetic film, 162
... first ferromagnetic film, 164 ... second ferromagnetic film, 167
a, 167b: electrodes, 169: high-resistance antiferromagnetic film.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (31) Priority claim number Japanese Patent Application No. 5-53612 (32) Priority date Hei 5 (1993) March 15 (33) Priority claim country Japan (JP) (72) Inventor Susumu Hashimoto 1 Komukai Toshiba-cho, Kawasaki-shi, Kanagawa Prefectural R & D Center, Toshiba Corporation (72) Inventor Atsushi Sawana 1 Komukai-shiba Cho, Saiwai-ku, Kawasaki, Kanagawa Shiba Research & Development Center ( 72) Inventor Yuzo Kamiguchi 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Within the Toshiba Research and Development Center (72) Inventor Masaji Sahashi 1 Komukai-Toshiba, Ko-ku, Kawasaki-shi, Kanagawa Toshiba Corporation R & D Center

Claims (1)

[Claims] 1. A magnetoresistive effect element comprising a laminated film in which at least a ferromagnetic film, a non-magnetic film, and a ferromagnetic film are sequentially laminated on a substrate, each of the two ferromagnetic films being a signal. When the magnetic field is zero, the magnetization pinned film maintains its magnetization direction substantially, and the magnetic field detection film detects the signal magnetic field by changing the magnetization due to the signal magnetic field. A magnetoresistive effect element, wherein the magnetization directions of the films are substantially orthogonal to each other, and a sense current is passed in a signal magnetic field direction.