JPH08264858A - Magnetoresistive effect element - Google Patents

Abstract

PURPOSE: To make small both the hysteresis and saturation magnetic field of a magnetoresistive effect element and to increase the rate of change of the magnetoresistance of the element by a method wherein the element is provided with a magnetic material of a constitution wherein magnetic metal particles containing at least one piece of a magnetic element out of magnetic elements consisting of Fe, Co and Ni are dispersed in a semiconductor matrix. CONSTITUTION: This magnetoresistive effect element has a magnetic material 3 of a constitution wherein magnetic metal particles 2 containing at least one kind of the magnetic element out of magnetic elements consisting of Fe, Co and Ni are dispersed in a semiconductor material 1. In a state that the magnetic field H of the element is zero, the directions of spins 4 of the particles 2 are random and in the case where the magnetic field H is larger than the saturation magnetic field Hs of the element, the directions of the spins 4 of the particles are made uniform. As a semiconductor material for constituting the matrix, a material having a small energy gap and a material having a great quantity of an impurity level are desirable. In concrete terms, it is desirable that the semiconductor material for constituting the matrix is material having an effective energy gap of IeV or smaller.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a magnetoresistive effect element using a magnetic material in which magnetic metal particles are dispersed in a semiconductor matrix.

[0002]

2. Description of the Related Art The magnetoresistive effect is a phenomenon in which the electric resistance changes when a magnetic field is applied to a certain kind of magnetic material.
It is used in magnetic field sensors and magnetic heads. For example,
A magnetoresistive effect element using a ferromagnetic material has characteristics of excellent temperature stability and a wide operating temperature range.

Conventionally, a thin film of permalloy alloy or the like has been widely used for a magnetoresistive effect element using a magnetic material, but the magnetoresistive change rate of the permalloy alloy thin film is as small as about 2 to 3%, so that it is sufficient. There is a problem that sensitivity cannot be obtained.

On the other hand, in recent years, as a new material exhibiting a magnetoresistive effect, a magnetic layer and a non-magnetic metal layer have a structure in which they are alternately laminated at a cycle of the order of several angstroms to several tens of angstroms. Attention has been paid to the fact that an artificial lattice film in which magnetic layers opposed to each other through magnetic coupling are magnetically coupled in a state where their magnetic moments are antiparallel to each other has a huge magnetoresistive effect. For example, (Fe / Cr) _n
Artificial lattice film (Phys. Rev. Lett. 61, 2)
472 (1988)) or an artificial lattice film of (Co / Cu) _n (J. Mag. Mag. Mat. 94, L1 (199).
1), Phys. Rev. Lett. 66,2125
(1991)) and the like have been found.

Such an artificial lattice film exhibits a remarkably large magnetoresistance change rate of several tens of percent as compared with the conventional permalloy alloy thin film. The giant magnetoresistive effect is due to electron scattering depending on the spin direction of the magnetic layer.

However, such an artificial lattice film is
In order to obtain a large magnetoresistive effect, it is necessary to increase the number of stacked layers, and the saturation magnetic field (the magnetic field at which the resistance value saturates) is as large as several tesla (T) or more. It has the problem of being unsuitable.

On the other hand, for the purpose of reducing the saturation magnetic field, a multilayer film having a sandwich structure of ferromagnetic layer / nonmagnetic layer / ferromagnetic layer is provided, and exchange bias is applied to one ferromagnetic layer to fix the magnetization. In other words, a so-called spin valve film has been developed which changes the relative angle between the magnetization directions of the two ferromagnetic layers by reversing the magnetization of the other ferromagnetic layer by an external magnetic field.

However, this spin valve film has a magnetoresistance change rate of about 3 to 4%, which is not so large, and the resistance of the multilayer film itself is as small as several tens of μΩcm, so that it is relatively large for detecting an external magnetic field. There is a problem that it is necessary to pass an electric current.

Furthermore, recently, unlike the artificial lattice film as described above, it has been found that a so-called granular magnetic film in which magnetic ultrafine particles are dispersed in a non-magnetic metal matrix also has a giant magnetoresistive effect. (For example, P
hys. Rev. Lett. 68, 3745 (199
2)).

In such a granular magnetic film, due to the nature of the magnetic ultrafine particles when no magnetic field is applied, the spins of each magnetic ultrafine particle face irregular directions with each other and have high resistance. When aligned in the direction of the magnetic field, the resistance decreases, and as a result, a magnetoresistive effect based on spin-dependent scattering appears.

[0011]

A granular magnetic film in which magnetic ultrafine particles are dispersed in such a non-magnetic metal matrix is easier to manufacture than an artificial lattice film, and the magnetoresistance change rate at room temperature is 20%. A large value can be obtained.
Furthermore, since ultrafine particles have a small particle size of about several nm and are a single magnetic domain, the hysteresis of the magnetoresistive curve is small, and therefore, it is expected that noise will be small when used as a magnetoresistive effect element.

In the conventional granular magnetic film as described above, if the particle size of the magnetic ultrafine particles is relatively large, it is difficult to obtain an irregular spin alignment due to ferromagnetic magnetic coupling, which results in a magnetic resistance. The effect is small and it is not preferable for use as a magnetoresistive effect element. Therefore, the particle size of the magnetic fine particles is made ultrafine to about several nm. But,
Since the ultrafine particles are dispersed in this way, the saturation magnetic field is large in nature, and in order to obtain a large magnetoresistive effect, it is essentially necessary to apply a large magnetic field of several tesla (T) or more. Has become an issue.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a magnetoresistive effect element having a small hysteresis and a large saturation magnetic field and a large magnetoresistance change rate.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, firstly, in a semiconductor matrix, F
There is provided a magnetoresistive effect element having a magnetic material in which magnetic metal particles containing at least one kind of magnetic elements composed of e, Co and Ni are dispersed.

Secondly, the present invention relates to at least one magnetic metal particle containing at least one magnetic element consisting of Fe, Co and Ni dispersed in a semiconductor matrix.
Provided is a magnetoresistive effect element having a laminated film of a magnetic layer of at least one layer and at least one nonmagnetic layer.

Thirdly, the present invention is at least one in which magnetic metal particles containing at least one magnetic element consisting of Fe, Co and Ni are dispersed in a semiconductor matrix.
A magnetoresistive effect element comprising a laminated film of a first magnetic layer of a layer and at least a second magnetic layer of at least one layer containing at least one of magnetic elements consisting of Fe, Co and Ni. provide.

Fourthly, the present invention relates to a first magnetic layer in which magnetic metal particles containing at least one of Fe, Co and Ni are dispersed in a semiconductor matrix, and a softer magnetic layer than the first magnetic layer. Provided is a magnetoresistive effect element having a laminated film with a second magnetic layer having magnetism.

In the conventional granular magnetic film having a structure in which magnetic metal particles are dispersed in a non-magnetic noble metal matrix, the reason why the saturation magnetic field is large is that the size of the magnetic metal particles is as small as a few nm and thus superparamagnetism is exhibited. It is in. If the size of the magnetic metal particles is made large enough not to exhibit superparamagnetism, the saturation magnetic field becomes smaller. In that case, however, the ferromagnetic magnetic coupling between the magnetic metal particles is strengthened. The spin directions of the particles are aligned, the spin directions do not change much even when a magnetic field is applied, and as a result, a large magnetoresistive effect cannot be obtained.

On the other hand, when the semiconductor is used as the matrix, the inventors of the present invention, since the antiferromagnetic magnetic coupling always works between the magnetic metal particles, the magnetic metal particles have no magnetic field. It was found that the spins of the two were disordered with respect to each other, and the strength of their magnetic coupling was much smaller than that with the metal matrix.

When the metal magnetic particles are dispersed in the semiconductor matrix, the semiconductor generally has a larger potential than the metal, so that conduction electrons from the metal flow through the semiconductor by the tunnel effect. Figure 1 shows the energy levels in this case.
Shown in In FIG. 1, the energy of the bottom of the metal conduction band is 0, and the height of the potential of the semiconductor is U. When a voltage V is applied to the sample, a potential difference of only eV occurs between the metal particles, and conduction electrons from one metal tunnel through the semiconductor and flow to the other metal. The state at this time is shown in FIG. 1 using the wave function Ψ _k (k is a wave number vector).

If the polarizability of the magnetic particles is P and the angle formed by the magnetization directions of the two magnetic particles (arrows in FIG. 1) is θ,
The conductance G is given by the following equation (JCSlonczewsk
i, Phys. Rev. B39, 6995 (1989)).

G = G ₀ (1 + P ² cos θ) From this equation, the difference in G between θ = 0 and θ = π is the largest. That is, the conductance or the resistance can be changed by changing θ with the external magnetic field. This is the magnetoresistive effect of a system composed of magnetic metal particles and a semiconductor matrix.

Since the tunnel current is generally small, the exchange coupling force between the magnetic metal particles is small. Therefore, in a system in which magnetic metal particles are dispersed in a semiconductor matrix, an antiferromagnetic magnetic coupling with a small coupling force is generated between the magnetic metal particles, compared to the conventional granular system in which magnetic metal particles are dispersed in a noble metal matrix. The saturation magnetic field is essentially small. Further, since the magnetic particles can be made larger than the superparamagnetic region, the saturation magnetic field becomes small also from this point.

That is, by using the semiconductor matrix, (1) even if the size of the magnetic metal particles exceeds the size of the ultrafine particles, it is possible to realize an irregular spin alignment with zero magnetic field, and Spin can be aligned by adding. Therefore, by applying a magnetic field, the electric resistance can be relatively lowered and a relatively large magnetoresistive effect can be obtained.

(2) Further, in this case, since the magnetic coupling between the magnetic metal particles is weak as described above, the saturation magnetic field can be reduced and the magnetoresistive effect can be exhibited with a small magnetic field. As a result, a highly sensitive magnetoresistive effect element is realized.

Further, since the magnetoresistive effect element in which the semiconductor is used as the matrix and the magnetic metal particles are dispersed in the semiconductor matrix as described above has a large specific resistance, there is an advantage that a large output voltage can be obtained. Therefore, the magnetoresistive effect can be detected with a small current, which is a great advantage for application to a magnetoresistive effect type magnetic head, a magnetic field sensor, or the like.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on Examples. FIG. 2 is a diagram schematically showing a magnetic body in the magnetoresistive effect element of the present invention having a basic structure in which magnetic metal particles are dispersed in a semiconductor matrix. As shown in this figure, the magnetoresistive effect element of the present invention has a magnetic substance 3 in which magnetic metal particles 2 containing at least one kind of a magnetic element consisting of Fe, Co and Ni are dispersed in a semiconductor matrix 1. . In FIG. 2A, the magnetic field H is zero, and the spins 4 of the magnetic metal particles 2 are randomly oriented. Further, (b) is a case where the magnetic field H is larger than the saturation magnetic field H _S , and the directions of the spins 4 of the magnetic metal particles are aligned.

As the semiconductor constituting the semiconductor matrix, a material having a small energy gap or a material having a large number of impurity levels is preferable, and specifically, an effective energy gap is preferably 1 eV or less. That is, when the effective energy gap of the semiconductor exceeds 1 eV, the insulating property tends to dominate, but the value is 1 eV.
If it is V or less, the tunnel current from the magnetic substance to the semiconductor becomes larger, and the carriers can be thermally excited to the conduction band of the semiconductor at room temperature, so that the conductance becomes larger and the magnetic coupling between the magnetic metal particles becomes larger. It can be made antiferromagnetic, and a larger magnetoresistance change rate can be obtained at room temperature. A more preferable range of the effective energy gap of the semiconductor is 0.1 eV or less.

The effective energy gap referred to here means the energy gap E _g of the intrinsic semiconductor, and also the difference between the impurity level in the impurity semiconductor and the bottom of the band of the conduction band or the impurity level and the Fermi level. It also means the difference with.

In any case, the semiconductor forming the matrix may be one having a large tunnel current and / or being thermally excited at room temperature and having a sufficient carrier concentration in the conduction band.

As such a semiconductor, a transition metal and S
An alloy or compound (crystal or amorphous) with i or Ge, amorphous Si, amorphous Ge, an impurity semiconductor, or the like can be used. The semiconductor constituting the matrix does not have to be one type, and may be composed of a composite phase of two or more types. In addition, the impurity semiconductor is
It may be n-type or p-type, and it is preferable that the carrier concentration is high to some extent, and the impurity concentration is 10 ²⁰ to
The range of 10 ²¹ cm ^-3 is preferable. Further, the semiconductor constituting the semiconductor matrix is not limited to a normal semiconductor, but may be an oxide having a defect or the like, which exhibits a semiconductor-like behavior, such as Al ₂ O ₃ or MgO _x .

The magnetic metal particles contain at least one kind of magnetic elements consisting of Fe, Co and Ni. In addition to simple elements of these elements, Co represented by CoFe is also used.
Base alloys, Fe-based alloys represented by Fe ₈ N, and Ni-based alloys represented by NiFe are included. In particular, the magnetic metal particles are preferably composed of at least two kinds of magnetic elements composed of Fe, Co and Ni. Thus, as magnetic metal particles, Fe, C
When using at least two kinds of o and Ni, the magnetoresistive effect in a small magnetic field becomes very large as compared with the case of using Fe, Co and Ni alone.

The size of the magnetic metal particles is 5 to 100 in terms of particle size.
The range is preferably in the range of nm, and if the particle size is within this range, the magnetic metal particles are single magnetic domains, so that the hysteresis of the magnetic resistance curve can be reduced. However, if the size is less than 5 nm, it becomes ultrafine particles and the saturation magnetic field becomes large, and if it exceeds 100 nm, the magnetoresistive effect is greatly reduced.

From the viewpoint of further reducing the saturation magnetic field, it is preferable that the magnetic anisotropy in the magnetic metal particles is small, and therefore it is preferable that the magnetic metal particles are made of an amorphous alloy. The reason for this is that the crystalline magnetic anisotropy of an amorphous alloy is essentially zero. Further, it is more preferable to use an amorphous alloy having substantially zero magnetostriction because the magnetic anisotropy based on magnetoelasticity is also reduced. As an amorphous alloy with substantially zero magnetostriction, (Ni _x Fe _y
Co _z ) _a X _100-a (where x = 0 to 0.10, y =
0.04-0.10, z = 0.90-0.94, x + y
+ Z = 1, a = 65 to 90, X is Nb, Zr, Hf, S
and at least one selected from the group consisting of i, B, C, and P).

Even if the magnetic metal particles are crystalline,
If the magnetostriction constant λ is 10 ⁻⁵ or less, which is close to zero, the saturation magnetic field can be reduced. Thus, the magnetostriction constant λ
Co ₉₀ Fe ₁₀ , Ni ₈₁ F as materials whose
e ₁₉ , Ni ₆₆ Fe ₁₆ Co _{18, and the} like.

A magnetic material in which magnetic metal particles are dispersed in such a semiconductor matrix is typically in the form of a thin film,
It can be produced by using an ordinary thin film forming apparatus such as a molecular beam epitaxy (MBE) method, various sputtering methods and vapor deposition methods. Further, it does not necessarily have to be a thin film, and may be a thin band formed by ultra-quenching or the like.

The magnetoresistive effect element of the present invention may be provided with a single layer of a magnetic material in which magnetic metal particles are dispersed in the above semiconductor matrix, but is not limited to this.
A laminated film of at least one magnetic layer in which magnetic metal particles containing at least one of magnetic elements consisting of Fe, Co and Ni are dispersed in a semiconductor matrix, and at least one non-magnetic layer, or Fe in a semiconductor matrix , C
at least one first magnetic layer in which magnetic metal particles containing at least one magnetic element consisting of o and Ni are dispersed, and at least one layer containing at least one magnetic element consisting of Fe, Co, and Ni May have a laminated film with the second magnetic layer. With such a laminated film, it is possible to control the shape of the magnetic metal particles dispersed in the semiconductor matrix and reduce the magnetic anisotropy based on the shape anisotropy. Along with the decrease, a larger magnetoresistive effect can be obtained.

These laminated films are formed, for example, in a semiconductor matrix 11 with Co, Fe and Ni as shown in FIG.
A structure in which magnetic layers 13 in which magnetic metal particles 12 containing at least one kind of a magnetic element consisting of are dispersed and non-magnetic layers 14 are alternately laminated, and as shown in FIG. , A first magnetic layer 23 in which magnetic metal particles 22 containing at least one kind of magnetic element composed of Fe and Ni are dispersed, and a second magnetic layer 24 composed of at least one kind of element selected from Fe, Co and Ni. It has a structure in which and are alternately stacked.

Even if such a laminated film has a structure in which a plurality of magnetic layers 13 and non-magnetic layers 14 or a plurality of first magnetic layers 23 and second magnetic layers 24 are laminated, It may have a structure in which the non-magnetic layer 14 is interposed between the magnetic layers 13 or a structure in which the second magnetic layer 24 is interposed between the pair of first magnetic layers 23. Further, considering only the shape of the magnetic metal particles dispersed in the semiconductor matrix to reduce the magnetic anisotropy based on the shape anisotropy, the magnetic layer 13 is provided between the pair of nonmagnetic layers 14. Or a structure in which the first magnetic layer 24 is interposed between the pair of second magnetic layers 24.
It may have a structure with the magnetic layer 23 interposed. Further, in the case of a structure in which these are alternately stacked, the number of stacked layers is not particularly limited. Further, in any of these cases, when there are a plurality of layers constituting the laminated film,
Their composition and film thickness need not be the same.

In the laminated film shown in FIG. 2, the thickness of the magnetic layer is preferably 0.5 to 20 nm, and the thickness of the non-magnetic layer is 1 to
10 nm is preferred. The material of the non-magnetic layer 14 interposed between the magnetic layers 13 is not particularly limited as long as it is non-magnetic, but a semiconductor is preferably used from the viewpoint of its resistance. Such semiconductor material is also not particularly limited.

On the other hand, in the laminated film shown in FIG. 3, the thickness of the first magnetic film is preferably 0.5 to 20 nm, and the thickness of the second magnetic film is preferably 2 to 30 nm. These laminated films are also typically thin films and can be formed using the thin film forming technique described above. Further, it may be a thin band formed by ultra-quenching. Further, such a laminated film may be formed by alternately forming a magnetic layer in which magnetic metal particles are dispersed in a semiconductor matrix and a non-magnetic layer or a magnetic layer. It can also be formed by alternately stacking magnetic layers and nonmagnetic layers made of at least one kind and then heat-treating them to diffuse the semiconductor element into the magnetic layers.

The magnetoresistive effect element according to the present invention also includes a first magnetic layer in which magnetic metal particles containing at least one of Fe, Co and Ni are dispersed in a semiconductor matrix, and the first magnetic layer. Second with softer magnetism
It may have a laminated film with the magnetic layer. As described above, by using the second magnetic layer having soft magnetism, the saturation magnetic field can be reduced while maintaining a sufficient magnetoresistance change rate.

Having soft magnetism means that the direction of the magnetic moment is easily reversed, and can be expressed by the magnitude of the coercive force (Hc) of a ferromagnetic material, for example. That is,
It can be said that the smaller Hc is, the softer the magnetism is. Here, having softer magnetism than the first magnetic layer means having a saturation magnetic field (Hs) smaller than that of the first magnetic layer, and the second magnetic layer has such soft magnetism. Therefore, for example, a substance exhibiting soft magnetism formed of a transition metal such as Fe, Co, or Ni or an alloy containing a transition metal, specifically, a conventionally used soft magnetic material such as permalloy, supermalloy or sendust. It is preferably formed.

The thickness of this second magnetic layer having soft magnetism is preferably about 0.5 to 100 nm, more preferably 1 to 20 nm. For example, as shown in FIG. 5, such a laminated film is formed by a first magnetic layer 33 in which magnetic metal particles 32 are dispersed in a semiconductor matrix 31 and a second magnetic layer 34 having soft magnetism. . After forming the first magnetic layer 33 on the substrate, the second magnetic layer 34 is formed.
May be formed, or the first magnetic layer 33 may be formed after the second magnetic layer 34 is formed. Further, the first magnetic layer 33 may be one or plural, and for example, as shown in FIG. 6, the second magnetic layer 34 is interposed between the two first magnetic layers 33. You may let me. In addition, the second magnetic layer 3
4 may be a single layer or a plurality of layers. For example, as shown in FIG. 7, the first magnetic layer 33 and the second magnetic layer 34 may be formed.
Alternatively, and may be laminated alternately.

In these magnetoresistive elements, the magnetic moment in the first magnetic layer 33 in which the metal magnetic particles 32 are dispersed is due to the interaction of the soft magnetic second magnetic layer 34 in which the magnetic moment is easily reversed. It is thought that it is easy to reverse. That is, it is considered that the magnetic moment can be reversed with a small magnetic field while maintaining the high magnetoresistance change rate obtained by the first magnetic layer 33 itself, and as a result, high sensitivity can be obtained.

Note that such a laminated film can also be formed by using the above-mentioned thin film forming technique or the like. When actually using the magnetoresistive effect element of the present invention, electrodes are required as shown in FIG. In FIG. 8, the magnetoresistive effect element 40 according to the present invention is formed on the substrate 43. Then, the pair of electrode portions 41 are provided in the magnetoresistive effect element 40. A pair of leads 42 are connected to the pair of electrode portions 41, respectively. An underlayer or overcoat made of a magnetic material or a nonmagnetic material may be provided on the magnetoresistive effect element.

[0047]

EXAMPLES Next, examples of magnetic materials in the magnetoresistive effect element of the present invention having a basic structure in which magnetic metal particles are dispersed in a semiconductor matrix will be shown. Example 1 First, Fe, Si, and Fe were sequentially formed on a thermally oxidized Si substrate by using a molecular beam epitaxy (MBE) method with Fe and Si as evaporation sources. The substrate temperature at this time was set to 100 ° C. Here, a plurality of films in which the film thickness of each Fe was fixed to 4 nm and the film thickness of Si was varied were prepared.

As a result of observing the structure of the obtained film using a transmission electron microscope, none of them had a clear laminated structure, and Fe fine particles having a particle diameter of about 10 to 20 nm or ferromagnetic Fe-Si. It had a so-called granular structure in which fine alloy particles were dispersed in a Si-rich matrix.

As a result of measuring the temperature change of the electric resistance of these films, the specific resistance at room temperature is between 180 μΩ · cm and 280 μΩ · cm depending on the film thickness of Si,
The resistivity decreased with increasing temperature near room temperature. From this, it was confirmed that the electric resistance was one digit or more higher than that of the conventional granular film using a metal matrix, and the matrix was a semiconductor. As an example, FIG. 9 shows the temperature change of the specific resistance when the film thickness of Si is 2 nm.

As a result of identifying the matrix phase of the film in the case where the film thickness of Si is 2 nm by using electron diffraction, it was confirmed that the non-magnetic semiconductor FeSi compound was the main phase and a small amount of amorphous Si was also contained. Was done.

Subsequently, the magnetoresistive effect of this film was measured by using the DC 4-terminal method. The obtained magnetoresistive effect curve is shown in FIG. As is clear from this figure, the rate of change in magnetoresistance is 3% and the saturation magnetic field is 0.03T (= 0.3O).
e). The value of this saturation magnetic field is two or more orders of magnitude smaller than that of the conventional granular magnetic film using a non-magnetic metal matrix.

(Embodiment 2) Next, by using MBE method with Co and Si as evaporation sources, C on a thermally oxidized Si substrate.
Films were formed in the order of o, Si, and Co. The substrate temperature at this time was set to 100 ° C. Here, a plurality of films in which the film thickness of each Co was fixed to 4 nm and the film thickness of Si was varied were formed.

As a result of observing the structure of the obtained film using a transmission electron microscope, none of them had a clear laminated structure, and Co fine particles having a particle diameter of about 10 to 20 nm or ferromagnetic Co—Si. It had a so-called granular structure in which fine alloy particles were dispersed in a Si-rich matrix.

As a result of identifying the matrix phase of these films by using electron diffraction, it was confirmed that the film consisted of a non-magnetic semiconductor CoSi phase and an amorphous Si phase. Then, the magnetoresistive effect was measured using the direct current 4-terminal method. S
When the film thickness of i was 2 nm, the magnetoresistance change rate was 8% and the saturation magnetic field was 0.08T. The value of this saturation magnetic field is two or more orders of magnitude smaller than that of the conventional granular magnetic film using a non-magnetic metal matrix.

(Example 3) Furthermore, thermal oxidation S was performed by using the MBE method with Ni ₈₀ Fe ₂₀ alloy and Si as evaporation sources.
The Ni ₈₀ Fe ₂₀ alloy, Si, and Ni ₈₀ Fe ₂₀ alloy were formed in this order on the i substrate. The substrate temperature at this time was set to 100 ° C. Here, a plurality of films in which the film thickness of each Ni ₈₀ Fe ₂₀ alloy was fixed to 5 nm and the film thickness of Si was varied were prepared.

As a result of observing the structure of the obtained film with a transmission electron microscope, Ni ₈₀ Fe ₂₀ alloy ferromagnetic fine particles having a grain size of about 10 to ₂₀ nm without any clear laminated structure were observed. Alternatively, it had a so-called granular structure in which Ni ₈₀ Fe ₂₀ —Si alloy ferromagnetic fine particles were dispersed in a Si-rich matrix.

As a result of identifying the matrix phase of these films by using electron diffraction, it was confirmed that the film consisted of a non-magnetic semiconductor NiFeSi phase and an amorphous Si phase. Then, the magnetoresistive effect was measured using the direct current 4-terminal method.
When the film thickness of Si was 2 nm, the magnetoresistance change rate was 4%, and the magnetostriction constant λ of the ferromagnetic fine particles was close to zero on the order of 10 ⁻⁶ , so that the saturation magnetic field was particularly small and was 0.01T. The value of this saturation magnetic field is two or more orders of magnitude smaller than that of the conventional granular magnetic film using a non-magnetic metal matrix.

[0058]

According to the present invention, there is provided a magnetoresistive effect element having both a small hysteresis and a saturated magnetic field and a large magnetoresistance change rate.

[Brief description of drawings]

FIG. 1 is a diagram showing the energy levels of adjacent magnetic metal fine particles and a semiconductor matrix between them, for explaining the principle of the present invention.

FIG. 2 is a sectional view schematically showing a magnetic body having a structure in which magnetic metal particles are dispersed in a semiconductor matrix in the magnetoresistive effect element of the present invention.

FIG. 3 is a sectional view showing a magnetoresistive effect element according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a magnetoresistive effect element according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a magnetoresistive effect element according to still another embodiment of the present invention.

6 is a cross-sectional view showing another example of the magnetoresistive effect element according to the embodiment shown in FIG.

7 is a sectional view showing still another example of the magnetoresistive effect element according to the embodiment shown in FIG.

FIG. 8 is a sectional view showing an actual use state of the magnetoresistive effect element according to the present invention.

FIG. 9 is a diagram showing a temperature change of electric resistance of the magnetic body according to the first embodiment of the invention.

FIG. 10 is a diagram showing a magnetoresistive effect curve of the magnetic body according to Example 1 of the invention.

[Explanation of symbols]

 1, 11, 21, 31 ... Semiconductor matrix 2, 12, 22 ... Magnetic metal particles 3 ... Magnetic material 4 ... Spin 13, 23, 24, 33 ... Magnetic layer 14 ... Nonmagnetic layer 34 ... Soft magnetic layer 40 ... Magnetoresistive element 41 ... Electrode part 42 ... Lead 43 ... Substrate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiho Okuno 1 Komukai-shi Toshiba-cho, Kawasaki-shi, Kanagawa Prefecture Toshiba Research and Development Center (72) Inventor Yoshiaki Saito Komukai, Saiwai-ku, Kawasaki-shi, Kanagawa Toshiba Town No. 1 Inside Toshiba Research and Development Center

Claims (9)

[Claims] 1. A magnetoresistive effect element comprising a magnetic substance in which magnetic metal particles containing at least one kind of magnetic elements consisting of Fe, Co and Ni are dispersed in a semiconductor matrix. 2. A laminate of at least one magnetic layer in which magnetic metal particles containing at least one of magnetic elements consisting of Fe, Co and Ni are dispersed in a semiconductor matrix, and at least one non-magnetic layer. A magnetoresistive effect element having a film. 3. A semiconductor matrix comprising at least one first magnetic layer in which magnetic metal particles containing at least one of magnetic elements consisting of Fe, Co and Ni are dispersed, and Fe, Co and Ni. A magnetoresistive effect element having a laminated film with at least one second magnetic layer containing at least one of magnetic elements. 4. The magnetic metal particle according to claim 1, wherein the magnetic metal particle contains at least two kinds of magnetic elements composed of Fe, Co and Ni.
The magnetoresistive effect element according to the item. 5. The magnetic metal particles have a particle size of 5 to 1
The magnetoresistive effect element according to claim 1, wherein the magnetoresistive effect element has a range of 00 nm. 6. The magnetoresistive effect element according to claim 1, wherein the magnetostriction of the magnetic metal particles is substantially zero. 7. The magnetoresistive element according to claim 1, wherein the effective energy gap of the semiconductor matrix is 1 eV or less. 8. The magnetoresistive effect element according to claim 2, wherein the non-magnetic layer is formed of a semiconductor. 9. A first magnetic layer in which magnetic metal particles containing at least one of Fe, Co, and Ni are dispersed in a semiconductor matrix, and a second magnetic layer having softer magnetism than the first magnetic layer. A magnetoresistive element having a laminated film with a magnetic layer.