JP3469675B2 - Magnetic spin element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel electric control device utilizing magnetic spin rearrangement.

[0002]

PRIOR ART AND PROBLEMS TO BE SOLVED BY THE INVENTION
Diodes used in the field of electronics and
And most electrical control elements such as transistors
It is made from semiconductors such as CON. Siri like this
Formed by doping impurities such as semiconductors
By joining the P-type semiconductor and the N-type semiconductor,
Diodes and transistors, as well as integrated circuits (I
C) and the like have been manufactured. The characteristics of such semiconductor devices
Property is the impurity that is doped, that is, the carrier
Concentration (generally 10¹⁸/ Cm ³Is controlled by
It

With the progress of higher integration and higher density, it has become difficult to meet the demand for higher integration and the like in the conventional semiconductor device due to the limitation of the carrier concentration and the like. An object of the present invention is to provide an electrical control element whose operation principle is completely different from that of such a conventional semiconductor element, and to provide a novel electrical control element utilizing magnetic spin rearrangement. It is a thing.

[0004]

A magnetic spin element according to the present invention comprises a first magnetic body and a second magnetic body, which are bonded directly or via an intermediate layer, a first magnetic body and a second magnetic body. Installed on the first magnetic body in order to pass the current through the joint surface between the magnetic bodies.
Provided on the first electrode terminal and the second magnetic body
A current through the second electrode terminal and the second magnetic body.
To apply a magnetic field to the second magnetic body by the second magnetic body
A third electrode terminal and a fourth electrode terminal provided on the upper side, and a current is applied between the third electrode terminal and the fourth electrode terminal.
It is characterized in that a magnetic field is applied by flowing the magnetic field .

In the present invention, the first magnetic body and the second magnetic body may be directly bonded or may be bonded via an intermediate layer. As the intermediate layer, for example, an insulating layer can be formed. Such an insulating layer is
The magnetic moments of the first magnetic body and the second magnetic body are parallel to each other, and the film thickness is set so that a current flows when brought into conduction. By forming the insulating layer as the intermediate layer, it is possible to reduce current leakage in a state where the magnetic moments of the first magnetic body and the second magnetic body are not parallel to each other, that is, in a non-conducting state. When the magnetic spin element of the present invention is used as, for example, the on / off ratio can be increased.

As the intermediate layer, for example, a magnetic field shielding layer such as Cu may be formed in order to reduce the influence of the magnetic field between the first magnetic body and the second magnetic body. When the first magnetic body and the second magnetic body are formed by, for example, a thin film forming method, by providing such an intermediate layer between the first magnetic body and the second magnetic body, the intermediate layer is formed on the intermediate layer. Since another magnetic substance can be formed, the influence of the base can be reduced to form the magnetic substance thin film.

[0007] As the magnetic field applying means in the magnetic spin device of the present invention, the means for applying by generating a magnetic field applying a current to the second magnetic material elements are used.

[0008] The magnetic spin device in one embodiment according to the present invention, the fourth electrode terminal, a second electrode terminal
Used as a common terminal .

In this embodiment, a magnetic field is applied to the second magnetic body by applying a voltage between the second electrode terminal and the third electrode terminal to cause a current to flow. In the present invention, the materials of the first magnetic body and the second magnetic body may be the same or different. As a magnetic field applying means, when a magnetic field is applied by changing the direction of the magnetic moment by causing an electric current to flow in the magnetic body, the holding force (Hc) can be changed so that the direction of the magnetic moment can be changed with a smaller current. A magnetic material having a small) is preferable. As a magnetic material having such a small coercive force, N
iFe, NiFeCo, etc. can be mentioned.

[0010]

1 to 4 are views for explaining the electrical spin control operation of the magnetic spin element of the present invention. With reference to FIG. 1, the first magnetic body 1 and the second magnetic body 2 are joined at a joint surface 3. Here, the first magnetic body 1 and the second magnetic body 2 are directly joined. The first magnetic body 1 is provided with a first electrode terminal 1a. The second
The magnetic body 2 is provided with a second electrode terminal 2a.
In this embodiment, a magnetic field is applied to the second magnetic body 2 by passing a current through the second magnetic body 2 to change the direction of its magnetic moment. Therefore, the second magnetic body 2 has a second
Electrode terminals 2b and 2c for passing a current through the magnetic body 2 are provided. These electrode terminals 2b and 2c can make the direction of the magnetic moment of the second magnetic body 2 parallel to the direction of the magnetic moment of the first magnetic body 1 by passing a current between these terminals. Is provided.

As shown by the arrow in FIG. 1, in this embodiment,
In the non-conducting state, the direction of the magnetic moment of the first magnetic body 1 and the direction of the magnetic moment of the second magnetic body 2 are antiparallel.

FIG. 2 is a diagram showing electron spin levels in the first magnetic body and the second magnetic body of the magnetic spin element in the non-conducting state shown in FIG. In FIG. 2, “1” indicates the electron spin level of the first magnetic body, and “2” indicates the electron spin level of the second magnetic body. As shown in FIG. 2, the electron spins of the Fermi level (E _F ) are oriented in opposite directions. Therefore, even if a voltage is applied between the first electrode terminal 1a and the second electrode terminal 2a, the electrons do not move between the bonding surfaces 3 and the first magnetic body 1 and the second magnetic body 2 are not moved. There is no current flowing between them.

In such a non-conducting state, the electrode terminal 2b
When a current is applied between the electrode and the electrode terminal 2c at an appropriate voltage, the direction of the magnetic moment of the second magnetic body 2 changes due to the generated magnetic field, and the magnetic moment of the magnetic moment changes in a direction parallel to the first magnetic body 1. The directions are rearranged.

FIG. 3 is a diagram showing a state after such rearrangement of magnetic moments. As shown by the arrow in FIG.
The direction of the magnetic moment of the second magnetic body 2 is parallel to the direction of the magnetic moment of the first magnetic body 1.

FIG. 4 shows the energy levels of electron spins in the state shown in FIG. As shown in FIG.
The electron spins at the Fermi level of the magnetic substance 1 and the magnetic substance 2 are aligned in the same direction, and therefore the magnetic substance 1 and the magnetic substance 2 are aligned.
Electrons move between them and a current flows.

Therefore, by applying a voltage between the first electrode terminal 1a and the second electrode terminal 2a shown in FIG.
A current can be passed between the first magnetic body 1 and the second magnetic body 2. Such a current flows through the joint surface 3.

In the magnetic spin element of the present invention, it is possible to return from the conducting state shown in FIG. 3 to the non-conducting state shown in FIG. 1 again. For example, by applying a voltage between the electrode terminals 2b and 2c of the second magnetic body 2 with a polarity opposite to that when conducting the second magnetic body 2, the magnetic moment of the second magnetic body 2 can be reduced. It can be in a state that is not parallel to the magnetic moment of 1, for example, an antiparallel state.
In the antiparallel state, the state as shown in FIG. 1 is restored again, and no current flows between the first electrode terminal 1a and the second electrode terminal 2a.

As described above, in the magnetic spin element of the present invention, the magnetic moment of the first magnetic substance is different from that of the second magnetic moment.
By independently changing the magnetic moment of the magnetic body, it is possible to realize a conductive state and a non-conductive state between the first magnetic body and the second magnetic body. Therefore, it can be used as an electrical control element such as a switching element.

Further, since the conductive state and the non-conductive state can be maintained, it can be used as a memory element.

[0020]

Embodiments FIGS. 5 to 8 show an embodiment in which a first magnetic body and a second magnetic body are joined together via an insulating layer as an intermediate layer. In the magnetic spin element of the present invention, as shown in FIGS. 1 and 3, the first magnetic body and the second magnetic body may be directly joined, but as shown in FIGS. You may join a 1st magnetic body and a 2nd magnetic body through a layer.

Referring to FIG. 5, an insulating layer 4 as an intermediate layer is formed between the first magnetic body 1 and the second magnetic body 2. By forming such an insulating layer, as described above, the leak current between the first magnetic body 1 and the second magnetic body 2 in the non-conducting state can be reduced. Further, by providing such an insulating layer, the first magnetic body and the second magnetic body
It is possible to solve the problem caused by direct contact of the magnetic substance at the bonding surface, and it is possible to improve the respective film characteristics. Further, when the magnetic body is manufactured by the thin film forming method, the magnetic body can be formed with less influence of the other magnetic body.

As shown in FIG. 5, also in this embodiment,
The magnetic body 1 is provided with a first electrode terminal 1a, and the second magnetic body 2 is provided with a second electrode terminal 2a. A voltage is applied between the first electrode terminal 1a and the second electrode terminal 2a.

Further, the direction of the magnetic moment of the second magnetic body 2 can be transferred to the direction of the magnetic moment of the first magnetic body 1 indicated by the arrow in FIG. 5 for the second magnetic body 2. Electrode terminals 2b and 2c are provided at these positions. In the state shown in FIG. 5, the direction of the magnetic moment of the second magnetic body 2 is antiparallel to the direction of the magnetic moment of the first magnetic body 1.

Therefore, as shown in FIG. 6, the electron spin directions at the Fermi level of the first magnetic body 1 and the second magnetic body 2 are opposite to each other, and the first magnetic body 1 to the second magnetic body 2 Electrons do not move to the magnetic body 2.

Therefore, in the state shown in FIG. 5, no current flows between the first magnetic body 1 and the second magnetic body 2 and the state is non-conductive. Electrode terminals 2b and 2c of the second magnetic body 2
When the voltage applied between the second magnetic substance 2 and the second magnetic substance 2 is increased.
A magnetic field is applied to the second magnetic body 2 by the flow of a current therein, and the direction of the magnetic moment of the second magnetic body 2 is aligned with the direction of the magnetic moment of the first magnetic body 1 and is in a parallel state. Become. FIG. 7 shows such a state. In the state shown in FIG. 7, as indicated by the arrow, the first magnetic body 1
And the direction of the magnetic moment of the second magnetic body 2 is in a parallel state.

In such a state, as shown in FIG. 8, the electron spin directions in the Fermi level of the first magnetic body 1 and the second magnetic body 2 are the same. Therefore,
Electrons move between the first magnetic body 1 and the second magnetic body 2 through the insulating layer 4. Therefore, a current starts to flow between the first magnetic body 1 and the second magnetic body 2, and a conductive state is established.

As described above, even when the intermediate layer is provided between the first magnetic body and the second magnetic body, the conductive state and the non-conductive state can be similarly realized. 5 and 7
In the example shown in FIG. 3, a total of three terminals, that is, the second electrode terminal 2a and the electrode terminals 2b and 2c for passing a current in the second magnetic body 2 are provided on the second magnetic body. However, since one of the electrode terminals 2b, 2c and the second electrode terminal 2a can be used as a common terminal, as shown in FIG. The electrode terminal 5 may be provided, and the second electrode terminal 6 and the third electrode terminal 7 may be provided on the second magnetic body 2. Therefore, the magnetic spin element of the present invention can have an element structure having three terminals.

10 to 12 are cross-sectional views showing the steps of manufacturing a magnetic spin element according to an embodiment of the present invention by a thin film forming method. Referring to FIG. 10A, a resist film 11 is formed on the substrate 10. The substrate 10 is preferably a non-magnetic substrate. Next, with reference to FIG. 10B, the resist film 11 is patterned into a resist film 11a in the same manner as the photolithography method generally used in the semiconductor forming process. Next, referring to FIG. 10C, the Au electrode film 12 is formed on the substrate 10 and the resist film 11a by a vapor deposition method. The thickness of the Au electrode film is about 200Å. Next, referring to FIG. 10D, the resist film 11a is lifted off to remove the substrate 10
Leaving only the Au electrode films at both ends thereof, and the electrode film 12a serving as the second electrode terminal and the electrode film 12b serving as the third electrode terminal.
And The distance between the electrode films 12a and 12b is 5 μm.
It was designed to be m.

Referring to FIG. 11A, next, a resist film 13 is formed on the substrate 10 and the electrode films 12a and 12b. Referring to FIG. 11B, next, by a normal photolithography method, the resist film 13 is patterned so as to leave only both ends thereof, to form resist films 13a and 13b. Next, referring to FIG. 11C, a NiFe layer (film thickness 500Å) 14, a SiO ₂ layer (film thickness 50Å) 15, N
The iFe layer (film thickness 500Å) 16 is sequentially laminated and formed. Next, referring to FIG. 11D, the resist films 13a and 13b are lifted off, so that the NiFe layer 14a and the SiO ₂ layer 15 are formed between the electrode films 12a and 12b.
A laminated film in which a and the NiFe layer 16a are laminated is formed. The NiFe layer 14a is in electrical contact with the electrode film 12a and the electrode film 12b at both ends.

When the NiFe layer 14 is formed,
It is formed by applying a magnetic field in a certain direction, whereby the magnetic moment of the thin film is formed in a uniform direction. When the NiFe layer 16 is formed, a magnetic field is applied in the opposite direction to form a thin film, whereby the magnetic moment is oriented in the opposite direction. As described above, NiFe
The magnetic moments of the layer 14 and the NiFe layer 16 are antiparallel to each other immediately after the thin film is formed.

Referring to FIG. 12A, next, a resist film 17 is formed on the NiFe layer 16a. Next, FIG.
Referring to (b), the resist film 17a is formed by removing the central portion of the resist film and leaving only the peripheral portion by photolithography. Next, with reference to FIG. 12C, an Au electrode film 18 (film thickness 200Å) is formed on the resist film 17a and the NiFe layer 16a. Next, FIG.
Referring to (d), the resist film 1 on the NiFe layer 16a
By lifting off 7a, an electrode film 18a made of an Au electrode film is formed in the central portion.

FIG. 13 is a plan view of the magnetic spin element of this embodiment shown in FIG. 12 (d) as seen from above. As shown in FIG. 13, the electrode films 12a and 12b are formed in a strip shape at both ends of the substrate 10, and the electrode film 18a is made of NiF.
It is formed in the central portion on the e layer 16a.

The magnetic spin element of this embodiment can be manufactured as described above. In the magnetic spin element shown in FIG. 12D, the NiFe layer 16a corresponds to the first magnetic body, the SiO ₂ layer 15a corresponds to the insulating layer as the intermediate layer, and the NiFe layer 14a corresponds to the second magnetic body. Equivalent to.
The electrode film 18a corresponds to the first electrode terminal, and the electrode films 12a and 12b correspond to the second electrode terminal and the third electrode terminal, respectively.

As described above, since the NiFe layer 14a and the NiFe layer 16a apply magnetic fields in mutually opposite directions during thin film formation, the directions of their magnetic moments are antiparallel to each other. There is.

Therefore, in the state shown in FIG. 12D, even if a voltage is applied between the electrode film 18a and the electrode film 12a, the directions of the magnetic moments of the NiFe layer 14a and the NiFe layer 16a are antiparallel. Because of this, no current flows and it is in a non-conducting state.

Next, when a voltage is applied between the electrode film 12a and the electrode film 12b to flow a current, a magnetic field is applied to the NiFe layer 14a, the direction of the magnetic moment is changed, and the direction of the magnetic moment of the NiFe layer 16a is changed. Are aligned in the same direction as and become parallel. When the magnetic moment directions are parallel to each other in this way, as described above, the electron spin directions of the Femil level are aligned, and the electrons can move.
Electrons flow through the SiO ₂ layer 15a between a and 14a. Therefore, a current flows between the electrode films 18a and 12a to establish a conductive state.

FIG. 15 is a diagram showing the voltage-current characteristics of the above embodiment. A voltage of mV was applied between the electrode films 18a and 12a, and the current value flowing between the electrode films 18a and 12a was measured while gradually increasing the voltage between the electrode films 12a and 12b as shown in FIG. As shown in FIG. 15, 0.7
Almost no current flowed up to V, and when 0.7 V was exceeded, the current gradually flowed, and when it reached 1 V, the current value rapidly increased. When the voltage between the electrode films 12a and 12b was decreased, the current value slightly decreased as shown in FIG. 15, but the high current value was still maintained.
Therefore, once the directions of the magnetic moments are aligned, the conductive state is maintained.

Next, when a voltage having the opposite polarity to that described above was applied between the electrode films 12a and 12b, the current value became 0, and the state of non-conduction was restored. This is because the magnetic moment of the NiFe layer 14a became antiparallel again.

FIG. 14 is a plan view showing a magnetic spin element of another embodiment according to the present invention. In this embodiment, FIG.
The portion of the laminated structure shown in (d) has a thin wire structure. As shown in FIG. 14, electrode films 22a and 22b are provided on both sides, and a plurality of thin film-structured laminated films 20 are arranged in parallel with each other with a groove 30 interposed therebetween. Further, the lowermost NiFe layer of each laminated film 20 is in electrical contact with the electrode films 22a and 22b, respectively. N of the top layer
An electrode film 28a serving as a first electrode terminal is provided in the center of the iFe layer 26a. As in this embodiment, the first
By making the magnetic body and the second magnetic body have a thin wire structure, respective magnetic moments are easily aligned in the longitudinal direction of the thin wire structure. Therefore, the directions of the magnetic moments in the respective magnetic bodies can be digitally realized in parallel or antiparallel. In the present invention,
The direction of the magnetic moment of the magnetic body is not limited to the two directions of the parallel state and the antiparallel state. The parallel state is preferably realized digitally.

FIG. 16 is a schematic view showing a magnetic spin element of still another embodiment according to the present invention. In the above embodiment, the same material is used as the first magnetic body and the second magnetic body. In the magnetic spin element of the present invention, as described above, the first magnetic body and the second magnetic body may be made of different materials. In the embodiment shown in FIG. 16, the first
The first magnetic characteristic is controlled by magnetically coupling the other magnetic body 8 to the magnetic body 1. Generally, in order to make the first magnetic substance and the second magnetic substance have the same Femil level, it is preferable that both are made of the same material. Therefore, in order to make one magnetic characteristic different from the other, In this way, the magnetic characteristics of the separate magnetic body can be controlled by magnetically coupling them.

[0041]

As described above, in the magnetic spin element according to the present invention, by changing the direction of the magnetic moment of one of the joined magnetic bodies with respect to the other magnetic body, the conduction state between the magnetic bodies and A non-conduction state can be realized. Therefore, it can be used as an electrical control element such as a rectifying element, an amplifying element, and a switching element, like the conventional semiconductor transistor and the like.

Further, the magnetic spin element of the present invention can be used as a memory element because it can maintain the conductive state or the non-conductive state once it is realized.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a non-conducting state of a magnetic spin element of the present invention.

FIG. 2 is a diagram showing electron spin levels in the state of FIG.

FIG. 3 is a schematic diagram showing a conducting state of the magnetic spin element of the present invention.

FIG. 4 is a diagram showing electron spin levels in the state of FIG.

FIG. 5 is a schematic diagram showing a non-conducting state in one embodiment of the magnetic spin device according to the present invention.

6 is a diagram showing energy levels of electron spins in the example shown in FIG.

FIG. 7 is a schematic diagram showing a conducting state in one embodiment of the magnetic spin device according to the present invention.

8 is a diagram showing energy levels of electron spins in the example shown in FIG. 7. FIG.

FIG. 9 is a schematic diagram showing a three-terminal structure of the magnetic spin element according to the present invention.

FIG. 10 is a cross-sectional view showing the manufacturing process of the magnetic spin element of the example according to the present invention.

FIG. 11 is a cross-sectional view showing the manufacturing process of the magnetic spin element of the example according to the present invention.

FIG. 12 is a cross-sectional view showing the manufacturing process of the magnetic spin element of the example according to the present invention.

FIG. 13 is a plan view of the magnetic spin element according to the example shown in FIG.

FIG. 14 is a plan view showing a magnetic spin element of another embodiment according to the present invention.

FIG. 15 is a diagram showing voltage-current characteristics of an example according to the present invention.

FIG. 16 is a schematic diagram showing a magnetic spin element of still another embodiment according to the present invention.

[Explanation of symbols]

1 ... the first magnetic body 2 ... second magnetic body 1a, 2a, 2b, 2c ... Electrode terminals 3 ... Bonding surface 4 ... Insulating layer 5 ... First electrode terminal 6 ... Second electrode terminal 7 ... Third electrode terminal

Continuation of front page (56) References JP-A-8-18118 (JP, A) JP-A-6-97531 (JP, A) JP-A-4-13014 (JP, A) JP-A-5-63254 (JP , A) JP-A-6-84347 (JP, A) JP-A-8-249875 (JP, A) JP-A-8-510095 (JP, A) International Publication 95/010112 (WO, A1) (58) Survey Areas (Int.Cl. ⁷ , DB name) H01L 43/08 G01R 33/09 G11B 5/39

Claims (3)

(57) [Claims] 1. A current passing through a first magnetic body and a second magnetic body, which are directly or through an intermediate layer, and a joint surface between the first magnetic body and the second magnetic body. To flow the first magnetic material on the first magnetic body.
A second electrode provided on the first electrode terminal and the second magnetic body;
The second magnetic to the applied to the electrode terminal, a magnetic field to the second magnetic body
And a third electrode terminal and the fourth electrode terminal provided on the body <br/>, current between said third electrode terminal and the fourth electrode terminal
A magnetic spin element characterized in that the magnetic field is applied by flowing a magnetic field . 2. The fourth electrode terminal is the second electrode.
The magnetic spin element according to claim 1, which is used as a terminal common to the terminal . 3. The magnetic spin element according to claim 1, wherein the intermediate layer is an insulating layer.