WO2014207818A1

WO2014207818A1 - Spin wave circuit

Info

Publication number: WO2014207818A1
Application number: PCT/JP2013/067354
Authority: WO
Inventors: 伊藤　顕知; 将貴山田; 勝哉三浦; 晋小川
Original assignee: 株式会社日立製作所
Priority date: 2013-06-25
Filing date: 2013-06-25
Publication date: 2014-12-31
Also published as: JP6081591B2; JPWO2014207818A1

Abstract

Provided is a spin wave guide which is compatible with an existing synchronous processing unit and for which power consumption is small, as well as a calculating circuit using same. A spin wave circuit is configured such that: upon a ferromagnetic line which propagates a spin wave and which is disposed upon a substrate, a plurality of areas in which ferromagnetic layers are stacked are provided across a non-magnetic intermediate layer; the ferromagnetic line and the ferromagnetic layers disposed thereupon are ferromagnetically coupled across the non-magnetic intermediate layer; and the easy axis of magnetization of the ferromagnetic line and the easy axis of magnetization of the ferromagnetic layers disposed thereupon are orthogonalized.

Description

Spin wave circuit

The present invention relates to a waveguide using a spin wave as an information transmission medium, an element, and an arithmetic circuit using the same.

Along with the explosive progress of the information society, the amount of information to be processed within a unit time increases exponentially, but the energy used for information processing can be drastically reduced due to global environment and energy constraints. There is a strong demand. Conventional CMOS-based semiconductor computing elements have improved performance along with miniaturization, but power consumption caused by leakage current that increases due to miniaturization, AC loss and Joule loss that occurs when current flows through the wiring The increase is remarkable and it is difficult to improve the operation speed. In order to cope with this situation, measures are taken to turn off the power of blocks that are not used, such as multi-core arrangement with a plurality of processors and power gating, all of which are considered to have limitations.

In recent years, as a technique for realizing low power consumption, attention has been paid to a spin current that transmits information by a spin flow without a current flow. The spin current is described in Non-Patent Document 1, for example. There are two types of spin currents: the electron spin current, in which electrons propagating on the Fermi surface are carriers, and the spin wave spin current, in which the precession of the spin confined to the atoms in the ferromagnetic waveguide propagates in the form of a wave. Type exists. Among them, the spin wave has a relatively long propagation distance of several tens of μm to several centimeters, and is expected to be applied to a large-scale arithmetic circuit.

For example, Patent Document 1 discloses a method for efficiently generating a spin wave and a method for controlling the phase of the spin wave, and further exhibits wave characteristics such as reflection, refraction, transmission, and interference of the spin wave. An applied information processing device is disclosed. In Non-Patent Document 2 and Patent Document 2, in addition to spin wave excitation, detection, and phase control methods, specific logic operation circuits (AND circuits, OR circuits, NAND circuits, NOR circuits, etc.) using spin waves are disclosed. ) Is disclosed, and it is suggested that power consumption can be significantly reduced when a spin wave arithmetic circuit is used.

Further, Non-Patent Document 3 describes a spin wave calculation compatible with the current synchronous arithmetic circuit in which written information is calculated using a spin wave and then stored again and further information processing proceeds. A circuit is disclosed. The contents are briefly shown below.

FIG. 1 is a schematic diagram of a spin wave arithmetic circuit shown in Non-Patent Document 3. 101 is a Si substrate, 102 is a wire-shaped (linear) spin wave waveguide, 103 is a ferromagnetic film having a magnetization easy axis in the in-plane direction of film such as Ni, 104 is a ferroelectric film such as PZT, and 105 is Al A metal electrode material film 106 and the like 106 are lines of a metal material such as Al. Reference numeral 107 denotes a region for exciting the spin wave, and reference numeral 108 denotes a region for detecting the spin wave. The ferromagnetic film 103, the ferroelectric film 104, and the metal electrode material film 105 constitute an electromagnetism (ME) effect element that can control the direction of magnetic anisotropy of the ferromagnetic film 103 when an electric field is applied.

In the following, description will be made using the x, y, z coordinate system shown in FIG. In this specification, the direction perpendicular to the film surface refers to the z-axis direction, and the direction parallel to the film surface refers to a direction in the xy plane. In this circuit, calculation using spin waves is performed as follows.

Information on “0” and “1” is written in the ferromagnetic film 103 by applying an electric field of +, − (specifically, upward and downward in the direction perpendicular to the film surface) to the ME element. Next, an electric field having the same polarity is again applied to the ME element to excite spin waves. While the spin wave propagates through the spin wave waveguide 102 and reaches the Ni film below the electrode line 106, the first calculation is performed using the wave nature of the spin wave, and the result is recorded on the Ni film. The Next, while the electrode line 106 is activated and the spin wave is excited again, and the spin wave propagates through the spin wave waveguide 102 and reaches the detection region 108, the second operation changes the wave nature of the spin wave. And recorded on the Ni film in the region 108. The calculation result is electrically detected through the ME element in the region 108.

2 to 4 are explanatory views showing the spin wave waveguide 102 and the ME element in more detail. FIG. 2 is a schematic diagram of a connection portion between the spin wave waveguide 102 and the ME element, and FIGS. 3 and 4 are schematic diagrams showing magnetization states of the spin wave waveguide and the Ni film.

As shown in FIG. 2, the ME element that is a laminate of the Ni film 103, the ferroelectric film 104, and the metal electrode material film 105 is arranged so as to be inserted into a part of the spin wave waveguide.

As shown in FIG. 3, in the spin wave waveguide 102, the magnetization of the ferromagnetic material is oriented in the direction perpendicular to the film surface. On the other hand, the magnetization of the Ni film 103 constituting the ME element has an easy axis in the in-plane direction. However, since the Ni film 103 is magnetically coupled to the perpendicularly magnetized ferromagnetic film 102, the magnetization direction cannot be completely directed in the in-film direction, and as shown in FIG. It faces in the direction between the membrane surfaces. Since there is one stable point in each of the + y / −y directions, information of “1” and “0” can be recorded on the Ni film.

5 to 8 are diagrams showing in more detail the information writing method using the wave nature of the spin wave described above. Consider the case where information 1 is recorded in the information input unit 301 as shown in FIG. 5, that is, the case where the magnetization is directed in the + y direction. In the case of FIG. 5, the length of the spin wave waveguide 102 connecting the information input unit 301 and the information output unit 303 is equal to n times the wavelength λ of the spin wave (nλ: n is a natural number). The wave 304 has an amplitude in the + y direction at the information output unit 303 after time t = λ / v (v is the speed of the spin wave) after the spin wave is excited. This information is recorded in the information output unit 303 as it is. On the other hand, when the information input unit 301 and the information output unit 303 are connected by a spin wave waveguide 102 having a length n + (1/2) times the wavelength λ of the spin wave as shown in FIG. The amplitude of the spin wave is in the −y direction, and this information is recorded in the information output unit 303 as it is. As shown in FIG. 7, the information input unit 301 and the information output unit 303 are connected by a spin wave waveguide having a length n times (nλ) the wavelength λ of the spin wave, and information 0, that is, −y is input to the information input unit 301. When the magnetization in the direction is recorded, the amplitude of the spin wave after time t is in the −y direction, and this information is recorded in the information output unit 303 as it is. As shown in FIG. 8, the information input unit 301 and the information output unit 303 are connected by a spin wave waveguide 102 having a length of n + 1/2 times the wavelength λ of the spin wave, and information 0, that is, When magnetization in the −y direction is recorded, the amplitude of the spin wave after time t is in the + y direction, and this information is recorded in the information output unit 303 as it is.

Special table 2009-508353 US 2007/0296516 A1

However, the spin wave arithmetic circuit shown above has the following problems.

In the spin wave arithmetic circuit described in Non-Patent Document 2, there is no mechanism for sequentially advancing the operation according to the clock, so the current mainstream synchronous information processing method cannot be used and the application is remarkable. Limited. In Non-Patent Document 3, this point is improved. However, in the spin wave circuit shown in FIG. 2, an easy axis is formed in the in-plane direction (y-axis direction) on a part of the spin wave waveguide having an easy axis in the film surface vertical direction (z-axis direction). The information recording part which has is inserted. In the case of such a structure, for example, as described in JOURNAL OF APPLIED PHYSICS Vol.104, 063921 (2008), reflection of spin waves occurs at the boundary between regions having different magnetic anisotropy, and spin There is a problem that waves do not propagate efficiently.

The present invention relates to a spin wave circuit that efficiently propagates spin waves without reflection of spin waves, an information recording unit structure that can record information efficiently, a recording control method, and an existing synchronous arithmetic circuit using the same A compatible arithmetic circuit is presented.

In the present invention, a ferromagnetic line for propagating spin waves is provided on a substrate, and a plurality of regions in which a ferromagnetic layer is laminated on a ferromagnetic line via a nonmagnetic intermediate layer are provided. A magnetic layer is ferromagnetically coupled through a nonmagnetic intermediate layer, and a spin wave circuit is configured by making the easy axis of magnetization of the ferromagnetic line orthogonal to the easy axis of magnetization of the ferromagnetic layer.

The ferromagnetic line and the ferromagnetic layer formed thereon can be made of Co, Fe or an alloy thereof, or a metal containing B in the Co, Fe or an alloy thereof.

The easy axis of the ferromagnetic line is parallel to the extending direction of the ferromagnetic line, and the easy axis of the ferromagnetic layer is perpendicular to the film surface. Alternatively, the magnetization easy axis of the ferromagnetic line is perpendicular to the extending direction of the ferromagnetic line and parallel to the substrate surface, and the magnetization easy axis of the ferromagnetic layer is perpendicular to the film surface. Alternatively, the magnetization easy axis of the ferromagnetic line is perpendicular to the substrate surface, and the magnetization easy axis of the ferromagnetic layer is parallel to the film surface.

Furthermore, an insulating layer is formed on the ferromagnetic layer, and an electrode made of a nonmagnetic metal is provided on the insulating layer. An insulating layer is formed on the ferromagnetic layer in a predetermined region, and an electrode made of a ferromagnetic material is provided on the insulating layer.

The ferromagnetic layer formed on the ferromagnetic line is preferably composed of two ferromagnetic layers whose magnetizations are antiparallel to each other and a nonmagnetic layer sandwiched between the two ferromagnetic layers. .

In the spin wave circuit of the present invention, a ferromagnetic line for propagating a spin wave is provided on a substrate, and a nonmagnetic intermediate layer, a ferromagnetic layer, an insulating layer, and an electrode layer are arranged in this order on the ferromagnetic line. Multiple layers are provided, and the ferromagnetic line and ferromagnetic layer are ferromagnetically coupled via a nonmagnetic intermediate layer. The easy axis of the ferromagnetic line and the easy axis of the ferromagnetic layer are orthogonal. The information input unit for exciting the spin wave propagating in the ferromagnetic line and the input of information, and the primary information for exciting the spin wave propagating in the ferromagnetic record Used as a recording unit or an information reproducing unit for reading information. Here, the electrode layer of the information reproducing unit is a conductive ferromagnetic layer.

Further, a plurality of ferromagnetic lines are crossed at the primary information recording unit and the information reproducing unit. Further, the distance between the adjacent information input unit, primary information recording unit, and information reproducing unit is an even multiple or an odd multiple of the half wavelength of the spin wave propagating through the ferromagnetic line.

According to the spin wave circuit operation control method of the present invention, a first voltage having a predetermined pulse voltage and a predetermined pulse width is applied to the electrode layer of the information input unit to apply information to the ferromagnetic layer constituting the information input unit. And applying a second voltage having a predetermined pulse width smaller than the predetermined threshold voltage to the electrode layer of the information input section or the primary information recording section where information is recorded, In addition to exciting a spin wave, a third voltage is applied to the electrode layer of the primary information recording unit or information reproducing unit to which information is to be transmitted from the information input unit or primary information recording unit to thereby reproduce the primary information recording unit or information reproducing unit. The step of lowering the energy barrier value of the magnetization transition of the ferromagnetic layer constituting the part and the application of the third voltage is stopped after information is recorded in the primary information recording part or information reproducing part to which information is to be transmitted And a step of performing.

Here, the timing at which the third voltage is applied is the same as the timing at which the second voltage is applied, or the timing after which the spin wave reaches the primary information recording unit or information reproducing unit to which information should be transmitted. To do.

In addition, the second voltage is a sine wave, and the third voltage is a rectangular wave.

According to the present invention, it is possible to provide a spin wave circuit and a recording control method that can efficiently record information without spin wave reflection and efficiently propagating spin waves.

Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

The figure which shows the prior art example of the arithmetic circuit using a spin wave waveguide. The schematic diagram of the connection part of the conventional spin wave waveguide and ME element. The schematic diagram which shows the magnetization state of a spin wave waveguide and Ni film. The schematic diagram which shows the magnetization state of a spin wave waveguide and Ni film. The figure which shows the recording method of the information in a spin wave waveguide. The figure which shows the recording method of the information in a spin wave waveguide. The figure which shows the recording method of the information in a spin wave waveguide. The figure which shows the recording method of the information in a spin wave waveguide. The schematic diagram which shows one Example of a spin wave waveguide and a spin wave circuit. The schematic diagram which shows one Example of a spin wave waveguide and a spin wave circuit. The schematic diagram which shows one Example of a spin wave waveguide and a spin wave circuit. The figure which shows the principle of the information writing to an information input part. The figure which shows the principle of a spin wave excitation. Explanatory drawing which shows the change of the internal magnetic field in the conventional spin wave waveguide. Explanatory drawing which shows the change of the internal magnetic field in the spin wave waveguide of this invention. The schematic diagram which shows one Example of a spin wave waveguide and a spin wave circuit. The figure which shows the voltage application to each part of the spin wave circuit which comprises a spin arithmetic circuit. The figure which shows the example of the waveform and application timing of the applied voltages Vi and Vo. The figure which shows the example of the spin wave circuit which implement | achieves AND logic and OR logic. The figure which shows the example of the spin wave circuit which implement | achieves NAND logic. The figure of the spin wave circuit which implement | achieves a selector circuit. The schematic diagram which shows the spin wave circuit which implement | achieves a full addition circuit. The schematic diagram which shows the integration method of a spin wave arithmetic circuit and a CMOS circuit.

Hereinafter, various embodiments of the present invention will be described with reference to the drawings.

FIG. 9 is a schematic diagram showing a first embodiment of a spin wave circuit including a spin wave waveguide and an information recording unit.

The ferromagnetic line 405 constituting the spin wave waveguide is formed on the base film 406 as a continuous long film. A spin wave circuit is configured by connecting regions such as the information input unit 407, the primary information recording unit 408, and the information reproducing unit 409 with a spin wave waveguide. The information input unit 407 and the primary information recording unit 408 include a nonmagnetic film 404, a ferromagnetic film 403 that performs information recording and spin wave excitation, an insulating film 402, and an electrode 401 on a ferromagnetic line 405. Consists of. In the information reproducing unit 409, a conductive ferromagnetic film 410 is used instead of the electrode 401, and the information reproducing unit 409 is a so-called ferromagnetic tunnel junction (MTJ).

Hereinafter, description will be made using the x, y, z coordinate system shown in FIG. In this embodiment, the direction perpendicular to the film surface refers to the z-axis direction, and the direction parallel to the film surface refers to a direction in the xy plane. This definition is exactly the same as in FIGS. 1 to 4, and the same definition is used in other embodiments described below.

In the embodiment of FIG. 9, the easy axis of the ferromagnetic line 405 constituting the spin wave waveguide is in the direction perpendicular to the film surface (z-axis). On the other hand, the easy magnetization axes of the

ferromagnetic films

403 and 410 are in the in-plane direction (y-axis). The ferromagnetic line 405 constituting the spin wave waveguide and the ferromagnetic film 403 are ferromagnetically coupled via the nonmagnetic film 404. For this reason, the magnetization direction of the ferromagnetic film 403 does not completely go in the film surface, but is slightly directed in the direction perpendicular to the film surface (z-axis) as shown in FIG. In the example of FIG. 9, there are two stable directions of magnetization of the ferromagnetic film 403 in the ± y-axis directions, and information “1” and “0” can be represented by the magnetizations directed in these directions.

FIGS. 10 and 11 are schematic views showing second and third embodiments of a spin wave circuit including a spin wave waveguide and an information recording unit.

In FIG. 10, 501 is an electrode, 502 is an insulating film, 503 is a ferromagnetic film for recording information and spin wave excitation, 504 is a non-magnetic film, 505 is a ferromagnetic line constituting a spin wave waveguide, and 506 is It is a base film. A spin wave circuit is configured by connecting the information input unit 507, the primary information recording unit 508, the information reproducing unit 509, and the like with a spin wave waveguide. In the information reproducing unit 509, a conductive ferromagnetic film 510 is used instead of the electrode 501, and the information reproducing unit 509 is a so-called ferromagnetic tunnel junction (MTJ). The basic configuration of the spin wave circuit shown in FIG. 10 is the same as that of FIG. 9, but in the case of FIG. 10, the magnetization easy axis of the ferromagnetic line 505 constituting the spin wave waveguide is in the in-film direction (x-axis). ), That is, the direction parallel to the extending direction of the ferromagnetic line. On the other hand, the easy axis of magnetization of the

ferromagnetic films

503 and 510 is in the direction perpendicular to the film surface (z axis). The ferromagnetic line 505 and the ferromagnetic film 503 constituting the spin wave waveguide are ferromagnetically coupled via the nonmagnetic film 504. For this reason, the magnetization direction of the ferromagnetic film 503 is not completely directed in the vertical direction, but rather is directed in the direction tilted slightly in the film in-plane direction (x-axis) as shown in FIG. In the example of FIG. 10, there are two stable directions of magnetization of the ferromagnetic film 503 in the ± z-axis direction, and information “1” and “0” can be represented by the magnetizations directed in these directions.

In FIG. 11, 511 is an electrode, 512 is an insulating film, 513 is a ferromagnetic film for recording information and exciting a spin wave, 514 is a non-magnetic film, 515 is a ferromagnetic line constituting a spin wave waveguide, Reference numeral 516 denotes a base film. A spin wave circuit is configured by connecting the information input unit 517, the primary information recording unit 518, the information reproducing unit 519, and the like with a spin wave waveguide. In the information reproducing unit 519, a conductive ferromagnetic film 520 is used instead of the electrode 511, and the information reproducing unit 519 is a so-called ferromagnetic tunnel junction (MTJ). The basic configuration of FIG. 11 is the same as that of FIG. 9, but in the case of FIG. 11, the easy axis of magnetization of the ferromagnetic line 515 constituting the spin wave waveguide is the in-plane direction (y-axis), that is, the ferromagnetic body. The direction is perpendicular to the line extending direction and parallel to the substrate surface. On the other hand, the easy magnetization axes of the

ferromagnetic films

513 and 520 are in the direction perpendicular to the film surface (z-axis). The ferromagnetic line 515 and the ferromagnetic film 513 constituting the spin wave waveguide are ferromagnetically coupled via the nonmagnetic film 514. For this reason, the magnetization direction of the ferromagnetic film 513 does not completely turn in the vertical direction, but rather in the direction tilted slightly in the film in-plane direction (y-axis) as shown in FIG. In the example of FIG. 11, there are two stable directions of magnetization of the ferromagnetic film 513 in the ± z-axis direction, and information “1” and “0” can be represented by the magnetizations directed in these directions.

As described above, in the present invention, it can be seen that there are three different combinations of the combination of the ferromagnetic line constituting the spin wave waveguide and the easy magnetization axis of the ferromagnetic film.

Next, materials used in these examples will be described. In the present invention, generation of a spin wave and recording of information are performed by applying an electric field. Therefore, as the material for the

ferromagnetic films

403, 503, and 513, first, Fe that can modulate the anisotropy of the interface with an electric field, an alloy of Co and Fe, or an alloy to which B is added is suitable. In that case, for the insulating

films

402, 502, and 512, MgO that gives a large modulation effect by an electric field to the interface anisotropy of the above material is a suitable material. In particular, the CoFeB film can modulate the value of the perpendicular magnetic anisotropy at the interface according to the film thickness t, and can control the direction of the magnetic anisotropy from the in-plane direction to the vertical direction according to the film thickness. , Vol.9, pp.721-724 (2010). In the following detailed description, CoFeB having a composition of Co ₂₀ Fe ₆₀ B ₂₀ will be described as an example, but the present invention is not necessarily limited thereto.

In this example, when the thickness t of CoFeB was t> 1.3 nm, the magnetization direction changed from the direction perpendicular to the film surface to the in-film direction. The critical film thickness at which the magnetization of the ferromagnetic film switches from perpendicular to in-plane varies depending on the composition of CoFeB, the material of the underlying film, and the like. In order to obtain a relatively large critical film thickness, the Co: Fe composition ratio of CoFeB is preferably 50:50 to 0: 100. When the CoFeB film is used as a material for a spin wave waveguide, the underlying

films

406 and 506 are used. , 516 is preferably an alloy based on Ta.

Regarding the film thickness of the CoFeB used as the ferromagnetic film constituting the spin waveguide and the ferromagnetic film of the information recording unit, an experimental example shown in Table 1 is shown, but is not limited to this.

When the saturation magnetization Ms of the CoFeB film was measured by a sample vibration magnetometer (VSM), the value was 1.6T.

As materials for the

nonmagnetic films

404, 504, and 514 that mediate the ferromagnetic coupling between the

ferromagnetic films

403, 503, and 513 and the

ferromagnetic lines

405, 505, and 515 constituting the spin wave waveguide, Ta, Ru, Ir, Os, Cr or the like is used. The film thickness of these materials is an important parameter that controls the strength of ferromagnetic coupling and must be carefully selected. Details will be described later.

As other materials for the ferromagnetic film and the ferromagnetic film of the information recording portion, Ni or an alloy based on Ni and Fe can be used in addition to a CoFe based alloy. The type of insulating film is not limited to the MgO film. For example, an oxide, nitride, or oxynitride containing at least one element selected from Al, Zn, Ti, Zr, Ni, Si, and Fe is used. Can be used. Al is suitable as a material for the

electrodes

401, 501, and 511, but a metal having a low resistivity such as Cu, Au, Ag, and alloys thereof is also desirable. The materials for the

base films

406, 506, and 516 are appropriately selected in order to accurately control the crystal growth of the material for the spin wave waveguide.

Hereinafter, the method of information recording and information transmission in the spin wave circuit using the spin wave waveguide of the present embodiment will be described by taking the case of FIG. 9 (Table 1, item number (1)) as an example. The width of the ferromagnetic line used in the experiment is 50 nm, and the dimensions of the

ferromagnetic films

403 and 410, the MgO film 402, and the electrode 401 provided in the information input unit 407, the primary information recording unit 408, and the information reproducing unit 407 are as follows. The x-axis direction is 25 nm, the y-axis direction is 50 nm, and the structure has in-plane magnetic anisotropy in the y-axis direction. In the present embodiment, the ferromagnetic film 403 has a rectangular shape, but this shape may be an elliptical shape, an octagonal shape, or a hexagonal shape having different values of the major axis / minor axis.

Information recording is performed by applying an electric field pulse to the information input unit 407. When an electric field pulse is applied from the CoFeB film 403 to the electrode 401 with the CoFeB film 403 having a positive polarity, the electronic state of the CoFeB film 403 near the interface with the MgO film 402 changes, and the perpendicular magnetic anisotropy near the interface increases. Become. Along with this, the magnetization starts precession as shown in FIG. When the applied voltage is greater than a certain threshold voltage Vth, the amplitude of magnetization precession increases and the magnetization starts precessing about the z-axis. If the period of precession is T and the width τ of the voltage pulse is approximately T / 2, the magnetization gradually decays around the other stable point after the voltage pulse is cut as shown in FIG. At the end, it falls to a stable point and stops.

When the pulse width τ is T, the magnetization stops at the original stable point. As described above, if τ = (T / 2) × (2n−1) (n is a natural number), a magnetization transition occurs, and if τ = nT, a magnetization transition does not occur. In this example, Vth was about 0.4 V and T = 300 ps. From the viewpoint of high-speed operation, it is desirable to perform recording at τ = 150 ps. However, if the peripheral circuit cannot achieve such a high speed, a pulse width of a high-order period such as τ = 450 ps or 750 ps may be used. In actual circuit operation, magnetization in the −y direction (information 0) or + y direction (information 1) is recorded in the CoFeB film of the information input unit 407 in the previous recording operation. If you want to record the same information as the previous time, do not apply a voltage, and if you want to rewrite the previous information, apply a pulse voltage of pulse width τ = (T / 2) × (2n−1). .

* Spin waves are used to transmit information. In this case, as shown in FIG. 13, a pulse voltage smaller than the threshold voltage Vth is applied. The length of the pulse to be applied is basically an integer multiple of the period T. In order to switch the two stable magnetization directions described above, it is necessary to supply the kinetic energy exceeding the energy barrier ΔE between the two to the magnetization. However, when V <Vth, the energy is insufficient, so Switching does not occur and the magnetization precesses around the magnetization stable point. This precession is transmitted as a spin wave from the information input unit 407 to the spin wave waveguide, and the spin wave records information 0 and 1 on the ferromagnetic film of the primary information recording unit 408.

The principle of writing by a spin wave basically follows the method shown in FIGS. 5 to 8, but in the present invention, the spin wave waveguide uses a material having a uniform easy axis, and a nonmagnetic film is formed on the spin wave waveguide. In this structure, a ferromagnetic film ferromagnetically coupled to the spin wave waveguide is provided as a recording film.

First, the reason why spin waves propagate efficiently in the spin wave waveguide of the present invention will be described. FIG. 14 is a diagram showing how the internal magnetic field Hin in the spin wave waveguide changes in the length direction of the waveguide with respect to the structure of the known example shown in FIGS. 2 and 3. The internal magnetic field Hin is the sum of all magnetic fields such as an externally applied magnetic field, an exchange coupling magnetic field, a demagnetizing field, and a magnetic field generated from a magnetostatic coupling. 2 and 3, it can be seen that the internal magnetic field changes greatly in the vicinity of the region 103 where information by spin waves is recorded. This is a phenomenon that occurs because the changes in the y-axis direction component Hin_y of the internal magnetic field and the z-axis direction component Hin_z of the internal magnetic field are not balanced in the vicinity of the region 103. When such a fluctuation of the internal magnetic field occurs inside the spin wave waveguide, the propagation characteristics of the spin wave are dominated by the internal magnetic field, so that the reflection of the spin wave occurs at a place where the internal magnetic field fluctuates. For this reason, the propagating spin wave does not easily reach the information recording area 103, and an efficient recording operation cannot be performed.

FIG. 15 is a diagram showing a change in the length direction of the waveguide of the internal magnetic field of the spin wave waveguide of the present invention. Since the changes in the y-axis direction component Hin_y of the internal magnetic field and the z-axis direction component Hin_z of the internal magnetic field are balanced near the region where the ferromagnetic film 403 is present, the magnitude of the total internal magnetic field Hin is the strength corresponding to the recording layer. Almost no change even immediately under the magnetic film 403. A major feature of the present invention is that the internal magnetic field in the spin wave waveguide is uniform. For this reason, the spin wave efficiently propagates directly below the ferromagnetic film 403, thereby enabling an efficient recording operation.

Another important parameter for performing an efficient recording operation is the strength of the ferromagnetic coupling through the nonmagnetic film 404 (504, 514). In the present invention, the ferromagnetic coupling magnetic field is controlled by changing the material of the nonmagnetic film and its film thickness. For example, when Ru is used as the nonmagnetic film material, the magnitude of the ferromagnetic coupling magnetic field can be changed between 500 and 3000 Oe by changing the film thickness between 0.4 and 1 nm. . In the case where the ferromagnetic coupling magnetic field is as small as less than 1000 Oe, even when a spin wave is excited by applying a maximum voltage of 0.4 V between the electrode 401 and the ferromagnetic film 403 in the structure of FIG. In the primary information recording unit 408, recording could not be performed on the ferromagnetic film 403. When the ferromagnetic coupling magnetic field was 1000 Oe, the spin wave information was recorded in the ferromagnetic film 403 of the primary information recording unit 408 when a spin wave was excited by applying a voltage of 0.4 V. When the ferromagnetic coupling magnetic field exceeded 2000 Oe, information was recorded in the ferromagnetic film 403 of the primary information recording unit 408 even when a spin wave was excited by applying a voltage of 0.3 V. When the ferromagnetic coupling magnetic field exceeds 2000 Oe, the voltage value at which recording is possible does not drop below 0.3V. That is, when CoFeB is used as the material of the ferromagnetic line 405 and the ferromagnetic film 403 constituting the spin wave waveguide corresponding to FIG. 9 (that is, Table 1 (1)), a ferromagnetic coupling magnetic field larger than 2000 Oe is applied. It is desirable to realize.

Assuming that the ferromagnetic coupling magnetic field is Hex, Hex = Jex / (Ms · t) (Ms is strong) between the above-described nonmagnetic film material and the ferromagnetic coupling constant Jex that can be controlled by the film thickness. There is a relationship of saturation magnetization of the ferromagnetic material constituting the magnetic line or ferromagnetic film, and t is the thickness of the spin wave waveguide or ferromagnetic film. There is a limit to the value of the ferromagnetic coupling constant Jex that can be controlled by the material of the nonmagnetic film and its film thickness. For example, the film thickness of the spin wave waveguide or the ferromagnetic film is reduced, or the spin wave waveguide or the ferromagnetic film Reducing the saturation magnetization Ms of the film is also effective in increasing Hex. For example, when NiFe whose saturation magnetization Ms is smaller than CoFeB is used as the material for the ferromagnetic line, the effective ferromagnetic coupling magnetic field Hex can be increased. However, when NiFe is used, in the case of FIG. 9 (that is, Table 1, item number (1)), the magnetization direction of the ferromagnetic line is the in-film direction, so that an external magnetic field is applied in the z-axis direction. Therefore, it is necessary to direct the magnetization direction of NiFe in the z-axis direction. The ferromagnetic film 403 is also affected by the external magnetic field due to the application of the external magnetic field. However, if the saturation magnetization Ms of the ferromagnetic film 403 is made larger than NiFe, the ferromagnetic film 403 is strongly affected by the demagnetizing field acting in the direction perpendicular to the film surface. The magnetization of the magnetic film 403 is still in the in-plane direction, and the operation is not greatly affected.

Next, cases (2) and (3) in Table 1 will be described. In these cases, the width of the ferromagnetic material line constituting the spin wave waveguide is 50 nm, the

information input units

507 and 517, the primary

information recording units

508 and 518, the

ferromagnetic films

503 and 513 in the

information reproducing units

509 and 519, The dimensions of the

MgO films

502 and 512 and the

electrodes

501 and 511 are 50 nm × 50 nm squares. This is because the easy axis of magnetization of the ferromagnetic film provided in these regions is in the direction perpendicular to the film surface (z-axis direction). This is because more coherent magnetization reversal can be realized without being affected by the magnetic field. In this embodiment, the

ferromagnetic films

503 and 513 have a square shape, but this shape may be a circular shape, a regular octagon, a regular hexagon, or the like.

Even in these cases, when the ferromagnetic coupling magnetic field exceeds 1000 Oe, when an applied voltage of Vth <0.4 V is applied to the

electrodes

501 and 511 of the

information input units

507 and 517, Information can be recorded by inducing magnetization reversal in the ferromagnetic films of the primary

information recording units

508 and 518. As in these examples, when the magnetization easy axis of the ferromagnetic material line constituting the spin wave waveguide is in the film plane (x or y axis direction), the table having the magnetization easy axis in the z axis direction is used. Since the magnetic anisotropy is smaller than the case of 1 (1), it is necessary to apply an external magnetic field in the x-axis or y-axis direction in order to make the magnetization state of the ferromagnetic line uniform. In this experiment, a magnetic field of 700 Oe was applied in the x-axis direction in the case of Table 1 (2) and 1500 Oe in the y-axis direction in the case of Table 1 (3). However, the

ferromagnetic films

503 and 513 are also affected by the external magnetic field due to the application of the external magnetic field, but since the magnetic anisotropy is sufficiently large in the direction perpendicular to the film surfaces of the

ferromagnetic films

503 and 513, the operation is greatly affected. Absent.

As described above, when the saturation magnetization Ms of the ferromagnetic line constituting the spin wave waveguide is reduced, the ferromagnetic coupling magnetic field can be effectively increased in the laminated structure having the same ferromagnetic coupling constant. Also in this case, for example, NiFe is a powerful material as a material for the spin wave waveguide. When NiFe is used, the magnitude of the demagnetizing field generated in the waveguide is smaller than that of CoFeB, so that the external magnetic field necessary for stabilizing the above-described magnetization state can also be reduced. For example, when a NiFe film having a thickness of 2 nm is used as a material for a spin wave waveguide, the external magnetic field in the x-axis direction is about 500 Oe in the case of Table 1 (2), and the y-axis direction in the case of Table 1 (3). The external magnetic field of can be about 1000 Oe.

Information transmission and calculation processing from the primary information recording unit 408 (508, 518) to the information reproduction unit 409 (509, 519) are performed in the same procedure as described above. That is, a spin voltage is excited by applying a pulse voltage of V <Vth to the electrodes of the primary information recording unit 408 (508, 518). Then, the spin wave propagates through the ferromagnetic line 405 (505, 515) constituting the spin wave waveguide, and information is written into the information reproducing unit 409 (509, 519). The length of the pulse applied to the electrode of the primary information recording unit is basically an integral multiple of the period T of the magnetization precession. Finally, a minute current is passed between the upper CoFeB film and the lower CoFeB film of the information reproducing unit 409 (509, 519), and the information (“0”, “0” recorded in the information reproducing unit by the TMR effect). 1 ") is read.

FIG. 16 is a schematic diagram showing an embodiment in which the ferromagnetic film 403 of FIG. 9 is composed of three laminated ferri layers 801, 802, and 803. In FIG. 16, 401 is an electrode, 402 is an insulating film, 801 is a first ferromagnetic film constituting the laminated ferri layer, 803 is a second ferromagnetic film constituting the laminated ferri layer, and 802 is two ferromagnetic films. A nonmagnetic film provided for

antiferromagnetically coupling

801 and 803, and a nonmagnetic film 404 provided for ferromagnetically coupling the ferromagnetic film 803 and the ferromagnetic material line 405 constituting the spin wave waveguide. A film 406 is a base film, 407 is an information input unit, 408 is a primary information recording unit, and 409 is an information reproducing unit.

In this example, the material of the structure other than the laminated ferri layer and its physical properties are the same as those in FIG. As a ferromagnetic film constituting the laminated ferri layer, CoFeB can be used as in FIG. In this case, as described with reference to the device operation in FIG. 9, when a negative voltage is applied to the electrode 401 via the insulating film 402 (for example, MgO), the ferromagnetic film 801 and the insulating film 402 are the same as in FIG. It is possible to modulate the interface magnetic anisotropy acting on the interface, and to record information on the laminated ferri layer or to excite spin waves in the laminated ferri layer. As the nonmagnetic film 802, for example, Ru, Ir, Os, Cr, or the like can be used. In FIG. 16, the magnetization directions of the

ferromagnetic films

801 and 803 constituting the laminated ferri layer are drawn so as to be substantially in the film plane (y-axis direction). Due to the magnetic coupling, a so-called cant state in which the magnetization directions of the two are slightly in the z-axis direction is obtained.

When the laminated ferrimagnetic structure is introduced, the leakage magnetic fields from the two

ferromagnetic films

801 and 803 are coupled to each other to form a so-called closed magnetic flux structure, so that the influence of the demagnetizing field at the time of magnetization reversal can be reduced, and writing with a smaller voltage is possible. In addition, it is possible to write information with a spin wave having a smaller amplitude. Actually, the same dimensions and materials as those in FIG. 9 are used except for the laminated ferri layer, CoFeB having a thickness of 1.4 nm is used for the ferromagnetic film 801, and CoFeB having a thickness of 1.5 nm is used for the ferromagnetic film 803. Compared with the structure of FIG. 9, the voltage to be applied to the electrode 401 of the information input unit 407 can be reduced by about 20% in order to excite the spin wave necessary for recording information in the primary information recording unit 408.

FIG. 16 shows an example of a structure of a spin wave circuit having a laminated ferri layer based on the structure of FIG. 9, but a spin wave circuit having a laminated ferri layer based on the structure of FIGS. It is also possible to configure. In that case, a material having an easy axis of magnetization in the direction perpendicular to the film surface (z-axis direction) is used for the ferromagnetic film constituting the laminated ferri layer. For example, a CoFeB film having a thickness of 1.3 nm or less can be used.

In the above, the basic spin wave waveguide structure, the recording of input information, the transmission of information by spin waves, and the recording operation have been described. As already described, in the spin wave arithmetic circuit of the present invention, the magnetizations of the

ferromagnetic films

403, 503, and 513 in any of FIGS. 9, 10, and 11 (that is, cases 1 to 3 in Table 1). It has been a condition for constituting the recording layer that has two directions equivalent in terms of energy. In order for these magnetizations oriented in the stable direction to transition to the other stable state, it is necessary to overcome the energy barrier between the two states, and the movement of the magnetization of the spin wave is via ferromagnetic coupling. The driving force that causes this transition. However, when a spin wave is excited by using an electric field as in the present invention, the amplitude of the excited spin wave is limited, and normally the saturation magnetization Ms of the ferromagnetic material line constituting the spin wave waveguide is 20 to 30% is the upper limit. It has also been reported that when a spin wave having an excessively large amplitude is excited, the waveform and phase of the spin wave are greatly disturbed by a nonlinear phenomenon caused in a ferromagnetic material. Therefore, a method capable of writing information by a spin wave having a relatively small amplitude that is excited with a small amount of power is strongly desired.

FIG. 17 and FIG. 18 show one method for solving the above-described problem, and are schematic diagrams showing the principle of efficiently recording spin wave information in the information recording unit. FIG. 17 is a diagram showing a spin wave circuit constituting the basic spin calculation circuit shown in FIG. 9 and voltage application to each part thereof. Vi represents a voltage applied to the information input unit 407, and Vo represents a voltage applied to the primary information recording unit 408.

FIG. 18 is a diagram showing waveforms and application timings of the voltage Vi applied to the information input unit 407, the voltage Vo applied to the primary information recording unit 408, and the like. In order to start transmission of information by a spin wave, the voltage Vi applied to the electrode of the information input unit 407 is turned on at a certain timing t1, as shown in FIG. As the Vi, a sinusoidal voltage having a certain frequency as shown in FIG. 18 is applied to excite a spin wave in the information input unit 407. However, the voltage waveform is not limited to a sine wave, and may be a rectangular waveform corresponding to a half cycle of the sine wave. The frequency of Vi varies depending on the ferromagnetic line material and structure constituting the spin wave waveguide, but is usually about several GHz to 10 GHz. In addition, the repetition period of the sinusoidal voltage to be applied depends on the ferromagnetic line material and structure of the spin wave waveguide and the ferromagnetic film material of the primary information recording unit, and the ferromagnetic line between the ferromagnetic line and the ferromagnetic film. Although it depends on the strength of the coupling, etc., it is usually set from 1 to several cycles.

Furthermore, at this timing t1, a negative voltage Vo is applied to the electrode of the primary information recording unit 408. Unlike the Vi, this voltage waveform is a rectangular waveform. The applied voltage Vo increases the interfacial magnetic anisotropy of the ferromagnetic film 403 (for example, CoFeB). In this way, the magnetization of the ferromagnetic film 403 described above is more vertically oriented, so that the value of the energy barrier that blocks the two energy stable points described above is reduced, and even with a smaller amplitude spin wave, the information Recording can be performed. The spin wave excited by the information input unit 407 reaches the primary information recording unit 408 at the timing t2, and performs a recording operation in the primary information recording unit 408. If the value of Vo is made zero at the timing t3 when the operation ends, the magnetization direction of the ferromagnetic film of the primary information recording unit 408 falls more in the in-plane direction, and the height of the energy barrier that blocks the two energy stable points Therefore, the recorded information continues to be recorded stably. The timing t3 is desirably a timing at which the amplitude of the spin wave propagating to the primary information recording unit 408 becomes zero.

In FIG. 18, the timing at which the voltage Vo is applied to the primary information recording unit 408 is the same as the timing t1 at which the electric field Vi is applied to the information input unit 407, but the timing is after t1 and It may be until the timing t2 when the spin wave reaches the primary information recording unit 408.

In the present embodiment, there is provided a method of configuring a selector and a full adder, which are AND logic, OR logic, NAND logic, which are basic gates, and the most basic combination circuit using the basic gate, using the waveguide of the present invention. Show.

FIG. 19 shows an example of a spin wave circuit that realizes AND logic, and FIG. 20 shows an example of a spin wave circuit that realizes NAND logic.

Input terminals

1001 and 1002 are two terminals for inputting information, and output terminal 1005 is a terminal for outputting a calculation result. The input terminal and the output terminal are connected by

spin wave waveguides

1003 and 1004, and the two

spin wave waveguides

1003 and 1004 intersect at the output terminal 1005. Hereinafter, in the recording unit of FIGS. 19 and 20, information when the magnetization is downward in the figure is represented by “0”, and information when the magnetization is upward is represented by “1”.

In the spin wave circuit constituting the AND logic shown in FIG. 19, the length of the

spin wave waveguides

1003 and 1004 is set to n times the wavelength λ of the spin wave, and information “0” is recorded in advance on the output terminal 1005. deep. The truth table is shown in Table 2.

In FIG. 19, since the lengths of the two

spin wave waveguides

1003 and 1004 are equal, when the phases of the input terminal 1001 and the input terminal 1002 are equal (that is, recorded information), the spin wave excited at the input terminal 1001 The spin waves excited at the input terminal 1002 intensify and interfere with each other. When the original input information is (“0”, “0”), “0” is obtained, and (“1”, “1”). “1” is recorded in the output terminal 1005.

On the other hand, when the phases (that is, recorded information) of the input terminal 1001 and the input terminal 1002 are not equal, the spin wave excited at the input terminal 1001 and the spin wave excited at the input terminal 1002 weaken each other and interfere with each other. Are not overwritten, and in either case, “0” remains recorded. Thus, the logic of Table 2 is realized.

OR logic can be realized by recording information “1” in advance in the output terminal 1002 in the spin wave circuit of FIG.

In the example of the spin wave circuit that realizes the NAND logic shown in FIG. 20, the length of the spin wave waveguide connecting the input terminal 1001 and the output terminal 1005 is (n + 1/2) times the wavelength λ of the spin wave. The length of the spin wave waveguide connecting the terminal 1002 and the output terminal 1005 is also (n + 1/2) times the wavelength λ of the spin wave. Further, “1” is recorded in advance in the output terminal 1005. The truth table is shown in Table 3.

In FIG. 20, when the information recorded in the two input terminals is (“0”, “0”), the phase of the spin wave at the input terminal 1001 and the phase of the spin wave at the input terminal 1002 are both shifted by π. The information “1” of the output terminal 1005 is overwritten by constructive interference. When the information recorded on the two input terminals is (“0”, “1”), the phase of the spin wave excited at the input terminal 1001 and the phase of the spin wave excited at the input terminal 1002 are shifted by π. , Both weakly interfere with each other, and the information “1” remains in the output terminal 1005 as it is.

When the information recorded in the two input terminals is (“1”, “0”), the phase of the spin wave excited at the input terminal 1001 and the spin wave excited at the input terminal 1002 are shifted by π. The two are weak and interfere, and the information “1” remains at the output terminal 1005. When the information recorded on the two input terminals is (“1”, “1”), the spin waves at the input terminal 1001 and the spin waves at the input terminal 1002 are both out of phase by π, so they are strengthened and interfered as they are. The information “0” is overwritten on the output terminal 1005.

As described above, NAND logic is realized. Since the NAND logic element is a universal circuit that realizes all logic operation circuits, any logic operation circuit can be realized using the spin wave waveguide of the present invention.

Next, a method for realizing a selector circuit, which is a slightly larger logic circuit combining AND logic and OR logic, will be described with reference to FIG.

First, in FIG. 21, the four

leftmost recording units

1101a, 1101b, 1101c, and 1101d are areas for writing input signals. The signal “0” is written in the

recording units

1103 and 1104, and the signal “1” is written in the recording unit 1105 before the calculation.

Next, an electric signal is synchronously input to the four recording units 1101a to 1101d to generate a spin wave. The spin wave propagates rightward in FIG. 21 through the spin wave waveguide. The spin wave propagating through the two spin wave waveguides in the upper left of FIG. 21 writes information in the recording unit 1103 where the two spin wave waveguides 1102 merge. Only in the case of “1”, the information written in the recording unit 1103 is “1”, that is, an AND operation is realized. On the other hand, in the spin wave waveguide at the lower left of FIG. 21, only the phase of the spin wave propagating through the spin wave waveguide 1102 is shifted by a half wavelength, so that only when 1101c is “1” and 1101d is “0”, recording is performed. “1” is written in the part 1104.

Next, a spin wave is generated by applying a voltage in synchronization with the

recording units

1103 and 1104. The spin wave further propagates rightward through the spin wave waveguide, and information is written in the recording unit 1105. Here, unless the information written in the

recording units

1103 and 1104 is (“0”, “0”), Information “1” is written in the recording unit 75. That is, the truth table shown in Table 4 below is established.

From the above, the selector function is realized in which the input signal 2 is selected when the control signal is “0” and the input signal 1 is selected when the control signal is “1”. In the above description, an example in which two

recording units

1103 and 1104 are installed in the selector intermediate unit is shown. In this way, the phase shift of the spin wave excited in the recording units 1101a to 1101d, or the phase shift of the spin wave due to the manufacturing error of the distance between the recording units 1101a to 1101d and the

recording units

1103 and 1104, can be detected once. Since it can be absorbed by the calculation operation, the operation margin can be expanded. However, in applications that require ultra-high speed operation, the

recording units

1103 and 1104 can be omitted, and the operation of the selector can be completed with a single clock.

The selector circuit shown in the present embodiment is, for example, a basic circuit of an FPGA (Field-Programmable Gate Array) logic element. Therefore, by combining the selector circuits and increasing the scale, the FPGA logic element is implemented in this embodiment. An example spin wave circuit can be used.

Next, FIG. 22 shows an example in which a full adder which is a larger-scale arithmetic circuit is configured using the spin wave waveguide of the present invention. In FIG. 22, Ai, Bi, Ci, Oi, Ai ′, Ci ′ (i = 1, 2,...) Drawn in a circle correspond to an information input unit, a primary information recording unit, an information output unit, and the like. Specifically, Ai and Bi are information recording units, and the i-th digit information “0” and “1” are recorded therein. Ci is a carry in the addition operation, and “1” is recorded when a carry occurs in the i-th operation result, and “0” is recorded when no carry occurs. Oi is an information output unit that outputs the calculation result of the i-th digit, and Ai ′, Ci ′, etc. are primary information recording units of the calculation result. FIG. 22 shows operations related to calculations up to the third stage. The arrow in the figure schematically represents the spin wave waveguide, and information is transmitted by the spin wave in the direction of the arrow. Specific operations are summarized in Table 5.

First, the operation of the first stage will be described. At timing T1, information is written to the information input units A1 and B1, and simultaneously information "0" is written to the information output unit O1 and the carry C2. At the next timing T2, the spin waves are excited at A1 and B1, and information is transmitted to C2, and at the same time, information is transmitted from A1 to A1 and from B1 to B1 ′. First, in the information transmission from A1, B1 to C2, by setting the distances of A1 and C2 and B1 and C2 to integer multiples of the wavelength of the spin wave, the AND operation described above is executed, and A1, B1 Only when both are “1”, “1” is recorded in C2, and “carry” occurs. On the other hand, in the information transmission of A1 → A1 and B1 → B1 ′, the distance between A1 and A1 is set to (2n−1) / 2 times the wavelength of the spin wave (n is a natural number), so that the information on A1 and A1 Is inverted from “0” to “1” or from “1” to “0”. On the other hand, by making the distance between B1 and B1 ′ an integral multiple of the wavelength of the spin wave, the information on B1 is transmitted to B1 ′ as it is. At the next timing T3, information transmission from A1, B1 ′ to O1, information transmission from C2 to C2 ′, writing to A2 and B2, and “0” writing to O2 are performed. Of these, only the transmission of information from A1 and B1 ′ to O1 is the first stage operation. By setting the distance between A1 and O1 and B1 ′ and O1 to be an integral multiple of the spin wave, A1 and B1 Only when the information is different, spin waves propagating to O1 strengthen each other, so that the information is rewritten from “0” to “1”. Therefore, the truth table is as shown in Table 6, and it can be seen that the operation of the adder is performed.

The operation in the second stage starts with information transmission from C2 to C2 ′, writing to A2 and B2, and writing “0” to O2 in information transmission at timing T3. Here, if the distance between C2 and C2 ′ is made an integral multiple of the spin wave distance, information is transmitted from C2 to C2 ′ without change. At the next timing T4, information transmission from A2 → A2 , C2 ′ → O2, C2 ′ → C2 ″ is performed. Here, the distance between A2 and A2 is (2n−1) / 2 of the wavelength of the spin wave. The distance (n is a natural number), the distance between C2 ′ and O2, and C2 ′ and C2 ″ is an integral multiple of the spin wave. The information is inverted from A2 to A2 , and the information is held and transmitted as it is in C2 ′ → O2 and C2 ′ → C2 ″. At the next timing T5, A2 → C3, B2 → C3, C2 ″ → Information transmission to C3 and information transmission from A2 to O2 and B2 to O2 are performed. The distances between these information recording parts are all integer multiples of the wavelength of the spin wave. First, in the information transmission of A2 → C3, B2 → C3, and C2 ″ → C3, the information having the larger number among A2, B2, and C2 ″ is written in C3. In the information transmission of A2 → O2, B2 → O2, only when the information of A2 and B2 is different, the information already written in O2 is rewritten. From the above, the operation truth table of the adder at the second stage is as shown in Table 7, and it can be seen that the operation of the full adder is realized.

The operation after the third stage is performed in the same manner as the operation of the second stage, and an addition of n-digit bits can be realized.

When the spin wave arithmetic circuit described above is mounted on an actual logic chip, it is necessary to use a conventional CMOS circuit as a peripheral circuit such as an interface with an external memory and a clock circuit. A method of integrating these two circuits is shown.

FIG. 23 is a schematic diagram showing an integration method of a spin wave arithmetic circuit and a CMOS circuit. In FIG. 23, reference numeral 1201 denotes a CMOS transistor, and reference numeral 1202 denotes a semiconductor layer in which the CMOS transistor is formed. Note that the CMOS transistor 1201 and the gate wiring 1203 extend in the depth direction of FIG. 23, but only the foremost part is shown in FIG. In FIG. 23, a normal planar CMOS transistor is shown. Depending on the process node to be used, a transistor having a three-dimensional structure such as a FIN-FET or a vertical transistor having a vertical channel may be used.

In this embodiment, the CMOS transistor forms a clock for controlling the timing of operation, a detection circuit for a read signal, an interface circuit for exchanging information with a peripheral memory and various devices, and the like. Used for. FIG. 23 shows an example of generating a clock. 1203 is a gate wiring for controlling the timing of sending the clock signal, 1204 is a global wiring for connecting the CMOS part for generating the clock and the spin wave arithmetic circuit section, and 1205 is an electrode. Reference numeral 1206 denotes a contact wiring that connects the CMOS transistor and the spin wave arithmetic circuit unit, and 1207 denotes a wiring layer in which these contact wirings are laid out. In the wiring portion 1207 as well, the illustration in the depth direction is omitted. The clock signal generated in the CMOS circuit portion is transmitted to the information recording unit / spin wave generating unit 1209 of the spin wave arithmetic circuit through the wiring 1208. The spin wave excited by the information recording unit / spin wave generation unit 1209 transmits a signal to the next information recording unit / spin wave generation device through the spin wave waveguide 1210. That is, the uppermost layer 1211 is a spin wave arithmetic circuit unit.

As described above, in the spin wave arithmetic circuit, the semiconductor part for forming the CMOS transistor in the lowermost layer can be formed, and the spin wave arithmetic circuit and the spin wave waveguide wiring network formed from the metal magnetic material in the uppermost layer can be formed. Compared with this logic chip, the area of the chip can be greatly reduced and the cost can be reduced. Furthermore, in the logic element part and also in the spin wave switch group, the voltage to be used is 0.5 V or less, which can be significantly lower than the conventional CMOS circuit, and the total number of devices can be greatly reduced. In the logic chip using the spin wave arithmetic circuit of this embodiment, it is possible to realize a significant reduction in power compared to the logic chip using the conventional CMOS circuit.

Next, a method for manufacturing a chip in which the CMOS and the spin wave arithmetic circuit shown in FIG. 23 are integrated will be briefly described. First, a CMOS transistor 1201 is formed on a semiconductor substrate such as a Si substrate using normal lithography, diffusion, and etching processes. Next, a via for the lowermost contact 1206 is formed, and, for example, a W film is formed after pulling a base film of Ti / TiN, and planarized by CMP. Subsequently, an insulating film is formed by CVD or the like, a hole for electrode formation is formed by lithography and dry etching, and a metal such as Cu is formed in the hole by a plating method, and CMP is performed. An electrode is produced by planarization. After that, a via for forming the next contact 1206 is formed by lithography and dry etching, a metal such as Cu is formed in the via by a plating method, and planarized by CMP. Cu vias are formed. This process is repeated to form a desired wiring layer 1207.

Finally, an uppermost electrode 1205 is formed and planarized by CMP, and then a base film / an insulating film such as a ferromagnetic film / MgO constituting the spin wave waveguide 1210 / an electrode film and a cap film for contact are formed. For example, the films are sequentially formed by a method such as sputtering. Subsequently, a wiring pattern of the spin wave waveguide is formed by lithography, the cap film is first patterned by dry etching, and then a ferromagnetic film / insulating film such as MgO constituting the spin wave waveguide 1210 is formed using the patterned cap film as a mask. / Pattern the electrode film. Subsequently, a mask for the information recording portion is formed by lithography, the pattern is transferred again to the cap film, and then the information recording portion is etched and patterned using the cap film as a mask. At this time, when using CoFeB, it is important to stop etching by detecting the end point with an end point monitor so that the thickness of the CoFeB of the spin wave waveguide becomes a predetermined value. Subsequently, after forming a passivation film such as SiN without breaking the vacuum, the wafer is taken out, an insulating film is formed by CVD or the like, and then flattened by CMP. Finally, a via connecting the electrode 1205 and the clock transmission wiring 1208 is formed, and a metal such as Cu is formed in the plating via and then flattened by CMP, and the contact 1206 and the information recording unit / spin wave generating unit 1209 are formed. After capping the cap film, wiring 1208 is formed on it with Cu or the like, and the whole is again embedded in the insulating film by CVD or the like, thereby completing the chip fabrication.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 101 ... Si substrate 102 ... Spin wave waveguide 103 ... In-plane magnetization ferromagnetic film 104 ... Ferroelectric film 105 ... Metal electrode material film 106 ... Metal line 107 ... Area | region 108 which excites a spin wave ... Spin wave detection area 301 ... Information Input unit 302 ... spin wave waveguide 303 ... information output unit 304 ... spin wave 401 ... electrode 402 ... insulating film 403 ... ferromagnetic film 404 ... nonmagnetic film 405 ... ferromagnetic material line 406 ... base film 407 ... information input unit 408 ... Primary information recording unit 409 ... information reproducing unit 501 ... electrode 502 ... insulating film 503 ... ferromagnetic film 504 ... nonmagnetic film 505 ... ferromagnetic line 506 ... underlayer film 507 ... information input unit 508 ... primary information recording unit 509 ... information Reproduction unit 511 ... electrode 512 ... insulating film 513 ... ferromagnetic film 514 ... nonmagnetic film 515 ... ferromagnetic material line 516 ... underlayer film 517 ... information input unit 518 ... one Information recording section 519 ... information reproducing section 801 ... ferromagnetic film 802 ... nonmagnetic film 803 ... ferromagnetic film 1001 ... input terminal 1002 ... input terminal 1003 ... spin wave waveguide 1004 ... spin wave waveguide 1005 ... output terminal 1006 ... information input section 1007 ... Primary recording unit 1008 ... Information reproducing unit 1101 ... Recording unit 1102 ... Spin wave waveguide 1103 ... Recording unit 1104 ... Recording unit 1105 ... Recording unit 1201 ... CMOS transistor 1202 ... CMOS semiconductor layer 1203 ... Gate wiring 1204 ... Global wiring 1205... Electrode 1206... Contact wiring 1207... CMOS semiconductor layer 1208... Wiring 1209... Information recording unit / spin wave generation unit 1210.

Claims

A ferromagnetic line for propagating spin waves is provided on the substrate,
A plurality of regions in which a ferromagnetic layer is laminated via a nonmagnetic intermediate layer on the ferromagnetic line are provided,
The ferromagnetic line and the ferromagnetic layer are ferromagnetically coupled via the nonmagnetic intermediate layer, and the easy axis of magnetization of the ferromagnetic line is orthogonal to the easy axis of magnetization of the ferromagnetic layer. A spin wave circuit.
2. The spin wave circuit according to claim 1, wherein the ferromagnetic line and the ferromagnetic layer are made of Co, Fe or an alloy thereof, or a metal containing B in the Co, Fe or an alloy thereof. A spin wave circuit.
2. The spin wave circuit according to claim 1, wherein an easy axis of magnetization of the ferromagnetic line is parallel to an extending direction of the ferromagnetic line, and an easy axis of magnetization of the ferromagnetic layer is perpendicular to the film surface. Characteristic spin wave circuit.
2. The spin wave circuit according to claim 1, wherein an easy axis of magnetization of the ferromagnetic line is perpendicular to a direction in which the ferromagnetic line is stretched and parallel to the substrate surface, and the easy axis of magnetization of the ferromagnetic layer is on the film surface. A spin wave circuit characterized by being vertical.
2. The spin wave circuit according to claim 1, wherein an easy axis of magnetization of the ferromagnetic line is perpendicular to a substrate surface, and an easy axis of magnetization of the ferromagnetic layer is parallel to the film surface. .
2. The spin wave circuit according to claim 1, wherein an insulating layer is formed on the ferromagnetic layer, and an electrode made of a nonmagnetic metal is provided on the insulating layer.
2. The spin wave circuit according to claim 1, wherein an insulating layer is formed on the ferromagnetic layer in a predetermined region, and an electrode made of a ferromagnetic material is provided on the insulating layer. Wave circuit.
2. The spin wave circuit according to claim 1, wherein the ferromagnetic layer is composed of two ferromagnetic layers whose magnetizations are antiparallel to each other and a nonmagnetic layer sandwiched between the two ferromagnetic layers. Characteristic spin wave circuit.
A ferromagnetic line for propagating spin waves is provided on the substrate, and a plurality of regions in which a nonmagnetic intermediate layer, a ferromagnetic layer, an insulating layer, and an electrode layer are stacked in this order are provided on the ferromagnetic line. The ferromagnetic line and the ferromagnetic layer are ferromagnetically coupled via the nonmagnetic intermediate layer, and the easy axis of magnetization of the ferromagnetic line is orthogonal to the easy axis of magnetization of the ferromagnetic layer,
The area includes information input and an information input unit for exciting spin waves propagating through the ferromagnetic line, primary recording of information, and primary information recording unit for exciting spin waves propagating through the ferromagnetic line The spin wave circuit is used as an information reproducing unit for reading information, and an electrode layer of the information reproducing unit is a conductive ferromagnetic layer.
10. The spin wave circuit according to claim 9, wherein a plurality of ferromagnetic lines intersect at the primary information recording unit and the information reproducing unit.
10. The spin wave circuit according to claim 9, wherein the distance between the adjacent regions is an even multiple or an odd multiple of a half wavelength of a spin wave propagating through the ferromagnetic line.
A plurality of regions in which a nonmagnetic intermediate layer, a ferromagnetic layer, an insulating layer, and an electrode layer are laminated in this order on a ferromagnetic line that propagates spin waves are provided as an information input unit, a primary information recording unit, or an information reproducing unit. The ferromagnetic line and the ferromagnetic layer are ferromagnetically coupled via the nonmagnetic intermediate layer, and the easy axis of the ferromagnetic line and the easy axis of the ferromagnetic layer are orthogonal to each other. The method for controlling the operation of the spin wave circuit, wherein the electrode layer of the information reproducing unit is a conductive ferromagnetic layer,
Applying a first voltage having a predetermined pulse voltage and a predetermined pulse width to the electrode layer of the information input unit to write information to the ferromagnetic layer constituting the information input unit;
A second voltage having a predetermined pulse width smaller than the predetermined threshold voltage is applied to the electrode layer of the information input unit or the primary information recording unit in which information is recorded to generate a spin wave in the ferromagnetic line. The primary information recording unit or the information reproducing unit is excited by applying a third voltage to the electrode layer of the primary information recording unit or the information reproducing unit to transmit information from the information input unit or the primary information recording unit. Reducing the value of the energy barrier of the magnetization transition of the ferromagnetic layer to constitute,
Stopping the application of the third voltage after information is recorded in the primary information recording unit or the information reproducing unit to which the information is to be transmitted;
An operation control method for a spin wave circuit, comprising:
The operation control method for a spin wave circuit according to claim 12,
The timing at which the third voltage is applied is the same as the timing at which the second voltage is applied or the timing after which the spin wave reaches the primary information recording unit or information reproducing unit to which the information is to be transmitted. An operation control method for a spin wave circuit, characterized in that:
The operation control method for a spin wave circuit according to claim 12,
The method of controlling operation of a spin wave circuit, wherein the second voltage is a sine wave and the third voltage is a rectangular wave.