JPH1079305A - Magnetic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen a magnetic device in magnetization curve hysteresis by a method wherein a spin state where magnetic layers arranged interposing a non-magnetic layer between them are anti-parallel to each other is formed without antiferromagnetic exchange coupling and magnetizing fixation. SOLUTION: A magnetic device is equipped with a laminated film provided with a magnetic layers 2 and 4 which are arranged sandwiching a non-magnetic layer 3,; which is made of an element selected from Si, GE, and SiGe alloy, between them and formed of one element selected out of Co, Ni, CoFe alloy, NiFe alloy, and CoNi alloy. An alloy layer 3a is formed on each of interfaces between the magnetic layers 2 and 4 and the non-magnetic layer 3 as an interface reaction layer, respectively. The magnetic layers 2 and 4 are uniaxially, magnetically anisotropic, and a dual second order magnetic coupling between the magnetic layers 2 and 4 through the intermediary of the non-magnetic layer 3 is predominant over all other magnetic couplings.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic element having a laminated film of a magnetic layer and a non-magnetic layer.

[0002]

2. Description of the Related Art A magnetic film is generally used for various magnetic elements such as a soft magnetic core, a magnetic head, a magnetic sensor, and a magnetoresistive element having a small high-frequency loss. These magnetic elements are required to have as high a sensitivity to an external magnetic field as possible, but in addition to that, a common requirement is to have a linear response. In order to obtain this linear response, it is desirable that the hysteresis of the magnetization curve be as small as possible. As a countermeasure, various countermeasures such as examination of the material composition and lamination of different substances are taken. This situation will be described below using a magnetoresistive element as an example.

[0003] Magnetoresistance effect
Is a phenomenon in which the electric resistance changes when a magnetic field is applied to a certain kind of magnetic material, and is used for a magnetic field sensor, a reproducing head of a magnetic recording device, and the like. A magnetoresistive effect element (hereinafter, referred to as an MR element) using a ferromagnetic material has excellent temperature stability and a wide operating temperature range. MR
Conventionally, a permalloy thin film such as an FeNi alloy has been used as an element.However, since the rate of change in magnetoresistance of the permalloy thin film is as small as about 2 to 3%, sufficient reproducing sensitivity can be obtained with a magnetic head using this. There is a problem that it cannot be obtained.

On the other hand, in recent years, as a material exhibiting a giant magnetoresistance effect, a magnetic metal layer and a nonmagnetic metal layer are alternately laminated at a period of several nm, and the magnetic moment of the magnetic layer facing each other via the nonmagnetic layer is reduced. Attention has been paid to a laminated film magnetically coupled in an antiparallel state, that is, an artificial lattice film. For example, Fe / C
r artificial lattice film (see Phys. Rev. Lett. 61, 2472 (1988), etc.) and Co / Cu artificial lattice film (J. Mag. Mag. Mater.
94, L1 (1991), Phys. Rev. Lett. 66, 2152 (1991))
Are found. Although such an artificial lattice film has a large magnetoresistance change rate, it has a problem that a large anti-ferromagnetic exchange coupling causes a large saturation magnetic field and a very large hysteresis.

In a sandwich film having a magnetic metal layer / non-magnetic metal layer / magnetic metal layer structure in which a pair of magnetic metal layers are stacked with a non-magnetic metal layer interposed therebetween, the non-magnetic metal layer has such a non-magnetic metal layer that the exchange coupling between the magnetic metal layers disappears. The thickness of the magnetic metal layer is increased, and an antiferromagnetic layer or the like is provided in contact with one of the magnetic metal layers to fix the spin of the magnetic layer (magnetized pinned layer) by exchange anisotropy and to fix the other magnetic layer. There is known a so-called spin valve film in which only the spin of a layer (magnetization free layer) can be easily switched by an external magnetic field. In this case, since the pair of magnetic metal layers is not exchange-coupled, the spin can be switched with a small magnetic field, so that a magnetoresistive element having higher sensitivity than an artificial lattice film having exchange coupling can be provided.

However, since the above-mentioned spin valve film also generally has hysteresis, a sense current is applied in a direction perpendicular to the exchange anisotropy to avoid the hysteresis, and the spin of the magnetization free layer is rotated. A so-called quadrature bias method, which changes according to the process, is employed.
Hysteresis is remarkably reduced by this rotational magnetization, but since the spin valve film has a small resistance and a small output voltage, it is necessary to increase the sense current in order to obtain a large output voltage. The current required for this is further increased. For this reason, electromigration is a problem in a conventional spin valve film employing the orthogonal bias method.

In addition to the giant magnetoresistive effect element, if a so-called perpendicular magnetoresistive effect, in which a current flows through a multilayer film in a direction perpendicular to the film surface, is used, an extremely large magnetoresistive effect can be obtained. Known (Phys. Rev. Le
tt. 66, 3060 (1991)). Further, in a sandwich film in which an insulating layer is interposed between two magnetic metal layers and the magnetization of one magnetic metal layer is fixed similarly to the spin valve film,
2. Description of the Related Art A magnetoresistance effect element using a tunnel current of an insulating layer by flowing a current in a direction perpendicular to a film surface, that is, a so-called ferromagnetic tunnel junction element is known. However, in a ferromagnetic tunnel junction device, it is difficult to form an insulating film having a high insulating property between magnetic metal layers, and at present, a reproducible ferromagnetic tunnel junction device has not been obtained.

[0008]

As described above, in the giant magnetoresistance effect element, the magnetoresistance effect is obtained by the scattering of conduction electrons depending on the spin. The large magnetoresistance effect is that the spin between the magnetic layers is in an antiparallel state. Is obtained when the state changes from. Therefore, it is necessary to form an anti-parallel spin state by some means, and in the conventional artificial lattice film, this is realized by antiferromagnetic exchange coupling between magnetic layers, and in a spin valve film or a ferromagnetic tunnel junction device, This is realized by fixing the spin of one magnetic layer and inverting the spin of the other magnetic layer by an external magnetic field.

However, the conventional artificial lattice film has problems that the saturation magnetic field is large and the hysteresis is very large due to the large antiferromagnetic exchange coupling. Also,
In the spin valve film, in addition to the sense current for obtaining a large output voltage, the required current is further increased by the orthogonal bias method for avoiding the hysteresis, so that electromigration is a problem. Furthermore, in a ferromagnetic tunnel junction device, it is difficult to form an insulating film having a high insulating property between magnetic metal layers, and a ferromagnetic tunnel junction device with reproducibility has been obtained.

SUMMARY OF THE INVENTION The present invention has been made to address such a problem, and is intended to reduce the antiparallel spin states between magnetic layers arranged via a nonmagnetic layer by means of antiferromagnetic exchange coupling, magnetization pinning, and the like. It proposes a structure that makes it possible to create a new method without depending on the magnetic element, thereby reducing the hysteresis of the magnetization curve, and further improving the saturation magnetic field, the resistance value of the laminated film, the insulation, etc. It is intended to provide.

[0011]

According to a first aspect of the present invention, there is provided a magnetic element including a laminated film having a plurality of magnetic layers disposed via a non-magnetic layer. Each of the magnetic layers has uniaxial magnetic anisotropy, and the magnetic coupling between the magnetic layers via the nonmagnetic layer is dominated by biquadratic magnetic coupling.

The magnetic element of the present invention is specifically described in claim 2
As described in the above, the magnetic layer is made of Co, Ni, CoFe
Alloy, NiFe alloy and CoNi alloy 1
And the nonmagnetic layer is made of one selected from Si, Ge, and a SiGe alloy. Further, as described in claim 3, an interface between the magnetic layer and the nonmagnetic layer is formed. And a reaction layer between the magnetic layer and the non-magnetic layer.

That is, for example, a magnetic layer (hereinafter, referred to as an M layer) mainly composed of one selected from Co, Ni, a CoFe alloy, a NiFe alloy, and a CoNi alloy;
By alternately laminating one kind of nonmagnetic layer (hereinafter, referred to as SM layer) selected from i, Ge, and SiGe alloy, a weak bilayer is formed between at least one pair of M layers disposed via the SΜ layer. The following magnetic coupling works.

The above-described interaction due to the biquadratic magnetic coupling is different from the antiparallel arrangement of spins between the magnetic layers due to the conventional biprimary magnetic coupling. Have. As described above, when the magnetic coupling between the magnetic layers via the nonmagnetic layer is dominated by biquadratic magnetic coupling, and when these magnetic layers each have uniaxial magnetic anisotropy, the spins between the magnetic layers are mutually shifted. By applying an external magnetic field in a direction perpendicular to the uniaxial magnetic anisotropy and making the spins of the pair of magnetic layers into a parallel magnetization state by a rotational magnetization process,
A magnetization curve with a small hysteresis can be obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment for implementing the magnetic element of the present invention will be described below.

FIG. 1 is a sectional view showing a main part of an embodiment of the magnetic element of the present invention. In FIG. 1, reference numeral 1 denotes a substrate, on which a laminated film 5 composed of a first magnetic layer 2, a non-magnetic layer 3, and a second magnetic layer 4 is formed in parallel with the substrate surface. I have. This first magnetic layer 2 / non-magnetic layer 3
/ Laminated film 5 of sandwich structure composed of second magnetic layer 4
Is used, for example, as a magnetoresistive film having a giant magnetoresistance effect, such as a spin valve film or a ferromagnetic tunnel junction film.

The structure of the laminated film according to the present invention is not limited to the sandwich structure in which the nonmagnetic layer 3 is interposed between the pair of magnetic layers 2 and 4 shown in FIG. It may be a multilayer laminated film 8 in which a large number of layers 6 and nonmagnetic layers 7 are alternately laminated. This multilayer laminated film 8 includes an artificial lattice film,
It is used, for example, as a magnetoresistive film having a giant magnetoresistive effect such as a perpendicular magnetoresistive film.

The sandwich laminated film 5 and the multilayer laminated film 8 can be manufactured by applying a normal thin film forming method such as a molecular beam epitaxy method (ΜBE method), various sputtering methods, and a vapor deposition method. Further, by forming a pair of electrodes for passing a sense current through the sandwich laminated film 5 and the multilayer laminated film 8, it is used as, for example, a magnetoresistive element.

The magnetic layers 2, 4, and 6 in the sandwich laminated film 5 and the multilayer laminated film 8 each have uniaxial magnetic anisotropy, and the first magnetic layer 2 with the nonmagnetic layer 3 interposed therebetween. The magnetic coupling between the magnetic layer and the second magnetic layer 4 and the magnetic coupling between the adjacent magnetic layers 6 via the non-magnetic layer 7 are dominated by biquadratic magnetic coupling. The biquadratic magnetic coupling between the magnetic layers is caused by the magnetic layers 2, 4, 6 and the nonmagnetic layers 3, 7
And the thickness of the non-magnetic layers 3 and 7 can be controlled.

That is, in realizing a state in which the bi-quadratic magnetic coupling predominates the magnetic coupling between the magnetic layers,
It is possible to apply a magnetic layer (M layer) mainly composed of one selected from Co, Ni, CoFe alloy, NiFe alloy and CoNi alloy to 4 and 6, and to apply Si, Ge and It is preferable to apply a non-magnetic layer (SM layer) made of one kind selected from SiGe alloys.

For example, when a magnetic layer made of Fe alone is applied to the magnetic layers 2, 4, and 6, ordinary bilinear magnetic coupling becomes dominant. In particular, by using Co or a Co alloy for the M layer, it is possible to increase the biquadratic magnetic coupling. Also, when a conductive metal material such as Cu or Au is applied to the nonmagnetic layers 3 and 7, ordinary bilinear magnetic coupling becomes dominant. By using one kind of semiconductor (SM layer) selected from Si, Ge, and SiGe alloy for.

The interface between the M layer and the SM layer as described above is generally located at the interface between the M layer and the S layer, as shown in FIGS.
Alloys (SM-M alloy) layers 3a and 7a of the constituent elements of the M layer and the constituent elements of the SM layer, which are reaction layers at the interface with the M layer, are formed. At this time, depending on the set film thickness of the nonmagnetic layers 3 and 7,
All interfaces may be SM-M alloy layers 3a and 7a, or some of the S３ layers 3b and 7b may remain as shown in FIG. 1 and FIG. In any of these films, weak biquadratic magnetic coupling acts between the magnetic layers (M layers) via the nonmagnetic layers 3 and 7.

FIG. 3 shows that the thickness of the Si film as the nonmagnetic layer is fixed to 1.2 nm on the thermally oxidized Si substrate by ion beam sputtering (acceleration voltage 700 V), and the Co film as the magnetic layer is formed. The film thickness t _Co (nm) was changed, (t _Co Co / 1.
A multilayer laminated film having a 2 nm Si) ₆ structure was prepared, and the results of measurement of the multilayer laminated film using a sample vibration type magnetometer are shown. FIG. 3 shows the saturation magnetization σ _s (Co) per unit volume of Co as C
FIG. 4 is a diagram showing a function as a function of a reciprocal of a film thickness. Both show a good linear relationship, and σ _s (Co) = σ _Co (1-2 △ d / t _Co ) holds. Here, Δd is the thickness of the interface alloy layer between Co and Si. From the intersection with the horizontal axis, 2 軸 d = 1.1 nm is obtained. From now on, 1.1 nm out of 1.2 nm is alloyed with Co and alloy layer (S
MM alloy layer), and the remaining 0.1 nm is found to remain as Si. This Si is amorphous Si
It is. As a result of conducting similar experiments for various SM film thicknesses, it was found that when the SM film thickness was 0.8 nm or more, in addition to the SM-M alloy layer, an SM layer not forming the SM layer remained.

In order to obtain a bi-secondary magnetic coupling, the thicknesses of the nonmagnetic layers 3 and 7 are determined by using only the SM-M alloy layers 3a and 7a,
The total thickness of the SM-M alloy layers 3a and 7a and the total thickness of the SΜ layers 3b and 7b is preferably in the range of 0.5 to 3 nm. If the thickness of the nonmagnetic layers 3 and 7 is less than 0.5 nm, ferromagnetic exchange coupling occurs, while if it exceeds 3 nm, the exchange magnetic coupling itself is reduced. The thickness of the magnetic layers (M layers) 2, 4, and 6 is preferably in the range of 0.5 to 10 nm.

In particular, as shown in FIG. 4, the thicknesses of the nonmagnetic layers 3 and 7 affect the residual magnetization ratio Μ _r / Μ _s (Μ _s is the saturation magnetization and Μ _r is the residual magnetization), which will be described in detail later. and, a range capable of reducing the residual magnetization Micromax _r, i.e. magnetic material susceptibility is large, and more preferably in the range of. 1 to 2 nm of the magnetoresistive element of high sensitivity can be obtained. FIG. 4 shows a case where the thickness of the Co film as the magnetic layer is fixed at 3 nm and the thickness t _Si (nm) of the Si film as the nonmagnetic layer is the same as in the multilayer laminated film shown in FIG. ), (3 nm Co / t
It is a measurement result of the multilayer laminated film of _Si Si) ₁₀ structure. In addition,
Similar results were obtained for the other M films and SM films.

The sandwich laminated film 5 and the multilayer laminated film 8
The magnetic layers 2, 4, and 6 have a uniaxial magnetic anisotropy as described above. This uniaxial magnetic anisotropy is
It can be introduced by film formation in a magnetic field, heat treatment in a magnetic field, induction of stress from a substrate, epitaxial growth on a single crystal substrate, or the like. The uniaxial magnetic anisotropy of the magnetic layers 2, 4, and 6 is as follows.
It is necessary to obtain a magnetization curve close to the parallel magnetization state in the rotation magnetization process.

The first magnetic layer 2 via the non-magnetic layer 3
Bi-secondary magnetic coupling is dominant between the magnetic layer 6 and the second magnetic layer 4 and between the adjacent magnetic layers 6 via the non-magnetic layer 7. The interaction due to the bi-secondary magnetic coupling has an effect of causing the spins between the magnetic layers to be oriented at 90 ° to each other, unlike the conventional anti-parallel arrangement of spins between the magnetic layers due to the bi-primary magnetic coupling. . Then, by the coexistence of the uniaxial magnetic anisotropy of the magnetic layers 2, 4, and 6 and the biquadratic magnetic coupling, the spins between the magnetic layers 2, 4 or between the magnetic layers 6 are brought into an antiparallel state with each other. And a magnetization curve with small hysteresis can be obtained.

That is, by the coexistence of the uniaxial magnetic anisotropy of the magnetic layers 2, 4, and 6 and the biquadratic magnetic coupling, the spin direction of the first magnetic layer 2 (arrow M _{1 in the} figure) and the second As shown in FIG. 5A, the spin directions of the magnetic layers 4 (arrows M _{2 in the} figure) (or the spin directions between adjacent magnetic layers 6) are 90 ° to 180 ° with each other in a state of zero external magnetic field. Make an angle between At this time, the angle becomes 180 as the uniaxial magnetic anisotropy becomes larger.
° approaches anti-parallel. In FIG. 5, an arrow X indicates the direction of the uniaxial magnetic anisotropy of the magnetic layers 2 and 4 (6).

As shown in FIG. 5B, the magnetic layers 2 and 4 (or the adjacent magnetic layer 6) having realized the anti-parallel state of the spins by the biquadratic magnetic coupling as shown in FIG. When an external magnetic field H is applied in a direction perpendicular to the uniaxial magnetic anisotropy X, the spin changes from an antiparallel state to a parallel state due to the rotational magnetization process. FIG. 6 shows a typical example of the magnetization curve at this time.

As shown in the magnetization curve of FIG. 6, the spin reversibly changes from the antiparallel state to the parallel state in the thick line portion. In particular, in the portion indicated by arrow A, an almost linear magnetization curve with extremely small hysteresis is obtained. can get. This is because an external magnetic field is applied in a direction perpendicular to the uniaxial magnetic anisotropy, and the magnetization process is set to rotational magnetization. Thereby, for example, in a magnetoresistive effect element, a good linear response of a change in magnetoresistance can be obtained. Further, as for the magnetoresistive element having the spin valve film and the ferromagnetic tunnel junction film, the electric resistance can be increased as described above. Furthermore, as for the magnetoresistive element having the spin valve film, the anti-parallel state of spin is realized irrespective of the bias current, so that the sense current can be further reduced. Therefore, it is possible to increase the output voltage without increasing the sense current while obtaining a good linear response, and it is possible to avoid the occurrence of electromigration and the like. In addition, with respect to the magnetoresistive effect element having the ferromagnetic tunnel junction film, good linear response can be obtained, and the insulation between the magnetic layers 2 and 4 by the nonmagnetic layer 3 can be sufficiently ensured.

Further, in the magnetoresistance effect element having the artificial lattice film, since the antiparallel state of spin between the magnetic layers 6 is realized by weak biquadratic magnetic coupling, the conventional antiferromagnetic exchange coupling is used. , The saturation magnetic field can be reduced, and good linear response with small hysteresis can be obtained. Further, when a current is applied in a direction perpendicular to the film surface, a magnetoresistive element capable of linear response with a high magnetoresistance change rate and output can be obtained.

Here, when the uniaxial magnetic anisotropy Κ _u exists in the film plane of the magnetic layer and the biquadratic magnetic coupling J ₂ exists between the magnetic layers, the external direction is perpendicular to the uniaxial magnetic anisotropy. When a magnetic field is applied, the saturation magnetic field H _s and the residual magnetization ratio Μ _r / Μ _s (Μ _s
Is the saturation magnetization, Μ _r is the residual magnetization) is given by the following equation. Here, t is the thickness of the magnetic layer.

[0033] _{H s = Ha + 4He ... (} 1) Ha = 2Κ u / Μ s, He = 2J 2 / Μ s · t ... (2) M r / Μ s = (1/2-Ha / 8He) 1 / ² … (3) When an external magnetic field is applied in a direction perpendicular to the uniaxial magnetic anisotropy of the magnetic layer, as described above, the magnetization process becomes rotational magnetization, so that almost linear magnetization with small hysteresis is obtained. A curve is obtained. In this case, as the remanence Μ _r and the saturation magnetic field H _s are smaller, the spins are closer to antiparallel at zero magnetic field, that is, the angle θ formed by the spins shown in FIG. 7 can be increased, and the spins can be aligned with a weak magnetic field. it can. Therefore, a magnetic material having a high magnetic susceptibility and a highly sensitive magnetoresistive element can be obtained.

For this purpose, from the above equations (1) to (3), H
It is desirable that a / He = 4 and Ha be small. That is, it is desirable that Κ _u (J ₂ / t) is close to 4 and Κ _u is small. For example, the H _s = 100 Oe,
Ha = Η _s / 2 = 50Oe next, and Κ _u = 25Μ _s. Here, if the ^{_{Μ s s = 1000emu / cm 3}} , K u = 2.5 × 10
⁴ erg / cm ³ . That Κ when _u is 10 ⁴ erg / cm ³ of the order, the saturation magnetic field is reduced to about 100 Oe, yet no magnetization curve hysteresis can be expected. Therefore,
The value of the uniaxial magnetic anisotropy is desirably at least 10 ⁵ erg / cm ³ or less. By satisfying these conditions,
After obtaining a magnetization curve and a magnetoresistance effect curve with extremely small hysteresis, a linear magnetization curve with a small saturation magnetic field can be obtained. Note that the magnetic element of the present invention is not limited to the magnetoresistance effect element described in the above-described embodiment, and can be applied to a normal thin-film magnetic head, a magnetic field sensor, an inductance element, and the like. An almost linear magnetization curve with extremely small hysteresis is effective.

[0035]

Next, an embodiment of the present invention will be described.

Example 1 A 3 nm-thick film was formed on each of a thermally oxidized Si substrate and a glass substrate by ion beam sputtering (acceleration voltage: 700 V).
Co film and a 1.5 nm-thick Si film are alternately stacked, and (3 nm
(Co / 1.5 nm Si) A multilayer laminated film having a ₁₀ structure was produced. FIG. 8 shows the magnetization curve of the (3 nm Co / 1.5 nm Si) ₁₀ film formed on the thermally oxidized Si substrate, and the (3 nm Co / 1.5 nm Si) film formed on the glass substrate.
FIG. 9 shows the magnetization curve of the (Co / 1.5 nm Si) ₁₀ film. FIG.
9 and FIG. 9 show magnetization curves when magnetic fields are applied in directions perpendicular to each other. From FIGS. 8 and 9,
The multilayer film on the glass substrate is isotropic,
i multilayer laminated film on the substrate is anisotropic, it can be seen that the uniaxial magnetic anisotropy K _u is present. Also, the unique hysteresis of the multilayer film on the thermally oxidized Si substrate is due to the biquadratic exchange coupling J ₂ acting between the Co films and the force acting to direct the spin between the Co films to 90 °. Because it is. That is because the coexistence of J ₂ and kappa _u. M _r /
Μ _s is 0.4, which is Κ _u / (J ₂ / t _Co ) = 2.7
And the angle formed by the spins between the Co films is about 140 °. On the other hand, the M _r / Μ _s of the film on the glass substrate is about 0.7, which is a result of the fact that the spins are at angles close to 90 ° to each other due to the presence of only the J ₂ bond.

The characteristic of the magnetization curve shown in FIG. 8A is that the magnetization changes reversibly in a wide magnetic field range (the thick line portion). This is because a magnetic field was applied in a direction perpendicular to the uniaxial magnetic anisotropy, and the magnetization process occurred due to rotational magnetization. Also saturating field is small and 50Oe are single magnetic recording isotropic and biquadratic magnetic coupling, K _u =
This is because both are as small as 1.4 × 10 ⁴ erg / cm ³ and J ₂ = 1.5 × 10 ⁻³ erg / cm ² . As described above, in the Co / Si multilayer laminated film formed on the thermally oxidized Si substrate, the small uniaxial magnetic anisotropy and the biquadratic magnetic coupling are introduced, so that the saturation magnetic field is small and the magnetization changes reversibly. Thus, a magnetization curve having a wide area can be obtained. Further, when an electric current was passed through the film surface and the electric resistance was measured, the electric resistance was as large as 500 μΩ / cm or more at room temperature. Example 2 In the same manner as in Example 1, a 3 nm Co /
A four-layer laminated film of 1.5 nm Si / 8 nm Co / 1.5 nm Si was produced. When the magnetization curve of this film was measured, uniaxial magnetic anisotropy was present, and when a magnetic field was applied in a direction perpendicular thereto, the magnetization curve was almost linear, and Μ _r / Μ _s was 0.15. This means that the spins of the two Co films are almost antiparallel to each other at zero magnetic field.

A current is applied to the laminated film in a direction perpendicular to the film surface, a magnetic field is applied in the film surface and in a direction perpendicular to the uniaxial magnetic anisotropy, and the magnetoresistance effect is measured using a DC four-terminal method. did. As a result, a substantially linear magnetoresistance effect curve without hysteresis was obtained, the magnetoresistance ratio was 25%, and the saturation magnetic field was 30 Oe. The resistance was very large at 50 Ω at zero magnetic field. This is because a non-alloyed amorphous Si layer remains at the interface.

In the above embodiment, the nonmagnetic layer is made of Si.
Is shown for the case where Ge is used, but Ge and Si-Ge
Similar results were obtained when an alloy was used. Similar results were obtained when Ni, CoFe alloy, or NiFe alloy was used as the magnetic layer. Further, similar results were obtained when the film was formed in a magnetic field to give uniaxial magnetic anisotropy in the film plane of the magnetic layer.

[0040]

As described above, according to the magnetic element of the present invention, an antiparallel state of spins is realized without depending on antiferromagnetic exchange coupling, magnetization pinning, and the like, and a magnetization curve with extremely small hysteresis is obtained. Can be obtained. Therefore, for example, in a magnetoresistive element, it is possible to improve the saturation magnetic field, the resistance value of the laminated film, the insulating property, and the like, and to obtain a good linear response.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a main part of an embodiment of a magnetic element of the present invention.

FIG. 2 is a cross-sectional view illustrating a main part configuration of another embodiment of the magnetic element of the present invention.

FIG. 3 is a graph showing a saturation magnetization σ _s (Co) per unit volume of Co of a (t _Co Co / 1.2 nm Si) ₆ film as a function of a reciprocal of a Co film thickness.

4 is a diagram showing the relationship between (3nmCo / t _{Si Si) 10} film M _r / M _s ratio and Si film thickness.

FIG. 5 is a diagram schematically showing a spin state of a magnetic layer in the magnetic element of the present invention.

FIG. 6 is a diagram showing an example of a typical magnetization curve of the magnetic element of the present invention.

FIG. 7 is a diagram schematically showing the relationship between the uniaxial magnetic anisotropy and the spin state of a magnetic layer and an external magnetic field in the magnetic element of the present invention.

FIG. 8 is a diagram showing a magnetization curve of a Co / Si multilayer laminated film formed on a thermally oxidized Si substrate in one example of the present invention.

FIG. 9 is a diagram showing a magnetization curve of a Co / Si multilayer laminated film formed on a glass substrate.

[Explanation of symbols]

 2, 4, 6 ... magnetic layer 3, 7 ... non-magnetic layer 3a, 7a ... SM-M alloy layer 3b, 7b ... SM layer 5 ... sandwich laminated film 8 ... multilayer laminated film

Claims (4)

[Claims] 1. A magnetic element comprising a laminated film having a plurality of magnetic layers arranged via a non-magnetic layer, wherein the magnetic layers each have uniaxial magnetic anisotropy, and the non-magnetic layer The magnetic coupling between the magnetic layers via the magnetic layer is dominated by biquadratic magnetic coupling. 2. The magnetic element according to claim 1, wherein the magnetic layer is mainly made of one selected from Co, Ni, a CoFe alloy, a NiFe alloy, and a CoNi alloy, and the nonmagnetic layer is a Si, Ge, and SiGe alloy. A magnetic element comprising one kind selected from the group consisting of: 3. The magnetic element according to claim 2, further comprising: a reaction layer between the magnetic layer and the non-magnetic layer at an interface between the magnetic layer and the non-magnetic layer. 4. The magnetic element according to claim 1, wherein the laminated film including the magnetic layer and the nonmagnetic layer is a magnetoresistive film exhibiting a giant magnetoresistance effect.