WO2019151254A1 - Information processing device - Google Patents

Information processing device Download PDF

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Publication number
WO2019151254A1
WO2019151254A1 PCT/JP2019/002986 JP2019002986W WO2019151254A1 WO 2019151254 A1 WO2019151254 A1 WO 2019151254A1 JP 2019002986 W JP2019002986 W JP 2019002986W WO 2019151254 A1 WO2019151254 A1 WO 2019151254A1
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Prior art keywords
input
spin
output
information processing
signal
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PCT/JP2019/002986
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French (fr)
Japanese (ja)
Inventor
了昌 中根
剛平 田中
廣瀬　明
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国立大学法人東京大学
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Publication of WO2019151254A1 publication Critical patent/WO2019151254A1/en

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06N—COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
    • G06N3/00—Computing arrangements based on biological models
    • G06N3/02—Neural networks
    • G06N3/06—Physical realisation, i.e. hardware implementation of neural networks, neurons or parts of neurons
    • G06N3/063—Physical realisation, i.e. hardware implementation of neural networks, neurons or parts of neurons using electronic means
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/82—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by variation of the magnetic field applied to the device

Definitions

  • the present invention relates to a signal information processing device, and more particularly to an information processing device capable of realizing a multi-input / multi-output input / output configuration.
  • CMOS Complementary Oxide Semiconductor
  • Patent Document 1 a device that imitates the function of a brain using a digital logic circuit has been proposed (for example, Patent Document 1).
  • Patent Document 1 Therefore, in the configuration of Patent Document 1, it is difficult to achieve both reduction in circuit scale and reduction in power consumption.
  • the present invention is a device for realizing a reservoir that determines an output based on a physical phenomenon that occurs with respect to an input, and is capable of reducing power consumption while preventing an increase in scale. It is to provide an output type information processing device.
  • the present invention A first structural layer maintained at a reference voltage; A second structural layer formed on the first structural layer; A third structural layer formed on the second structural layer, the surface opposite to the surface in contact with the second structural layer being a signal input / output surface; Have The third structure layer is One or more first electrodes that can be formed at any place on the input / output surface, and a predetermined electrical signal is input as an input signal; One or more second electrodes that can be formed at any location on the input / output surface except for the location where the first electrode is formed, and that output a predetermined electrical signal as an output signal; With The second structural layer comprises: When a predetermined electrical signal is input as an input signal to the first electrode, a spin wave is excited in the first region corresponding to the first electrode, and a second corresponding to the second electrode Having a structure for propagating the spin wave in a region; The spin waves have different characteristics depending on the positions of the first region and the second region.
  • FIG. 1 is a block diagram showing a configuration example of an information processing device according to an embodiment of the present invention.
  • FIG. 2A is a diagram illustrating an example of a cross-sectional structure of an input region and an output region in the information processing device according to the embodiment.
  • FIG. 2B is a diagram illustrating an example of a cross-sectional structure of an input region and an output region in the information processing device according to the embodiment.
  • FIG. 3A is a diagram for describing a condition (simulation condition) of a simulation executed in one embodiment.
  • FIG. 3B is a diagram for explaining a condition (simulation condition) of a simulation executed in one embodiment.
  • FIG. 4A is a diagram for describing a spin wave excitation signal used for simulation in one embodiment.
  • FIG. 4B is a diagram for explaining a spin wave excitation signal used for simulation in one embodiment.
  • FIG. 5 is a diagram illustrating a spatial distribution of spin waves detected in each Detector region when an excitation signal is input once to an input electrode provided in the Exciter 1 in a simulation according to an embodiment.
  • FIG. 6 is a diagram illustrating a spatial distribution of spin waves that are excited when an excitation signal is input twice to the input electrodes provided in the Exciters 1 and 2 in the simulation of the embodiment.
  • FIG. 7 is a diagram illustrating temporal changes of the sx component and the sz component of the spin wave in the simulation of the embodiment.
  • FIG. 8 is a diagram illustrating an sx component and an envelope of a spin wave detected in each detector region when an excitation signal is input twice to the input electrodes corresponding to Exciters 1 and 2 in the simulation of one embodiment. It is.
  • FIG. 9 is a diagram illustrating a simulation result of the reservoir computing using the information processing device according to the embodiment.
  • FIG. 10A is a diagram illustrating a simulation result of one embodiment.
  • FIG. 10B is a diagram illustrating a simulation result according to an embodiment.
  • FIG. 11 is a diagram showing a configuration of an information processing device in Modification 2 of the present invention.
  • FIG. 12A is a cross-sectional view illustrating a configuration example inside the via hole in the second modification.
  • FIG. 12B is a cross-sectional view illustrating a configuration example inside the via hole in the second modification.
  • FIG. 12C is a cross-sectional view illustrating a configuration example inside the via hole in the second modification.
  • FIG. 13A is a cross-sectional view illustrating a configuration example inside a via hole in Modification 2.
  • FIG. 13B is a cross-sectional view illustrating a configuration example inside the via hole in the second modification.
  • An information processing device includes: A first structural layer maintained at a reference voltage; A second structural layer formed on the first structural layer; A third structural layer formed on the second structural layer, the surface opposite to the surface in contact with the second structural layer being a signal input / output surface; Have The third structure layer is One or more first electrodes that can be formed at any place on the input / output surface, and a predetermined electrical signal is input as an input signal; One or more second electrodes that can be formed at any location on the input / output surface except for the location where the first electrode is formed, and that output a predetermined electrical signal as an output signal; With The second structural layer comprises: When a predetermined electrical signal is input as an input signal to the first electrode, a spin wave is excited in the first region corresponding to the first electrode, and a second corresponding to the second electrode Having a structure for propagating the spin wave in a region; The spin wave characteristics are different depending on the positions of the first region and the second region.
  • the information processing device outputs the same signal as the first signal if the arrangement position of at least one of the first electrode and the second electrode formed in the third structure layer is different. Even if it is input to the electrode, a different signal can be extracted from the second electrode, so even when a plurality of first electrodes (input electrodes) and second electrodes (output electrodes) are formed on the input / output surface, Different signals can be output for each input signal.
  • the information processing device can be placed in the in-plane positions of the input electrode and the output electrode by appropriately installing the input electrode and the output electrode in the input / output surface without using a logic circuit. Accordingly, the input signal can be output while being appropriately processed.
  • the information processing device is based on a physical phenomenon of spin wave propagation without using electric wiring and without using a potential change due to charge and discharge of electrons, such as regardless of an operation clock. It can be configured as a multi-input and multi-output device.
  • the information processing device can achieve low power consumption while preventing an increase in scale in a reservoir that determines an output based on a physical phenomenon that occurs with respect to the input.
  • a multi-input / multi-output type information processing device can be realized.
  • the information processing device can realize a wide variety of output variations depending on the order of input signals, the input signal waveform of analog data, or a combination of multiple inputs. It can be used as a device for realizing a large number of information processing such as a neural network.
  • an information processing device includes: It has a configuration further comprising magnetic field applying means for applying a DC external magnetic field having a predetermined value in an arbitrary direction of the input / output surface.
  • the information processing device can apply a magnetic field in an arbitrary direction to the spins of the atoms in the input region. For example, nonlinear interference is likely to occur. It is possible to excite spin waves having predetermined characteristics such as.
  • the information processing device uses an interaction such as a prior spin distribution state or interference between spin waves in a spin wave propagation process when there are a large number of inputs.
  • a multi-input / multi-output type information processing device can be realized.
  • the information processing device can set an external magnetic field environment that is asymmetric with respect to space, and can generate spin waves that cause nonlinear interference in the second structure layer. Therefore, it is possible to ensure the diversity of output with respect to the input signal and also to ensure high adaptability when realizing the function corresponding to the neural network.
  • an information processing device includes: When the input signal is input and the spin wave propagates through the second structure layer, The history remains as a spin distribution state, and the signal value of the output signal with respect to the input signal input thereafter is changed based on the history.
  • the information processing device can change the output signal according to the history of the input signal input in the past, and can generate a new spin wave through the interaction of each signal. Therefore, it is possible to exhibit high adaptability even when performing an operation for obtaining a weighted sum of past memories without providing a memory.
  • the information processing device can realize output characteristics reflecting the correlation between the data.
  • an information processing device includes:
  • the third structure layer is The region where the first electrode and the second electrode are formed has a via hole, and the via hole is filled with a material having a composition different from that of other portions.
  • the information processing device can improve energy efficiency when converting an electric signal and a spin wave.
  • an information processing device includes: The third structure layer is Deformed with the input of the input signal,
  • the second structural layer comprises: The spin wave is excited in the first region by changing the magnetic anisotropy of the first region in accordance with the deformation of the third structure layer.
  • the information processing device can excite spin waves in the first region by configuring the third structure layer with the piezoelectric body. If the piezoelectric material is embedded in the via hole, the conversion efficiency between the electric signal and the spin wave can be improved.
  • an information processing device includes: The third structure layer is With the input of the input signal, the polarization vector changes, The second structural layer comprises: The spin wave is excited in the first region by a change in magnetic anisotropy due to an electromagnetic effect caused by a change in polarization vector in the third structure layer. .
  • the information processing device can excite spin waves in the first region by configuring the third structure layer with a dielectric, and thus the structure of the information processing device If the dielectric is embedded in the via hole, the conversion efficiency between the electric signal and the spin wave can be improved.
  • an information processing device includes: The material embedded in the via hole is As the input signal is input, a spin-polarized electron current is generated,
  • the second structural layer comprises: The spin wave is excited in the first region due to a change in magnetic anisotropy due to an electromagnetic effect caused by a spin-polarized electron flow generated in the material in the via hole. doing.
  • the information processing device can improve the energy efficiency when converting an electrical signal and a spin wave with a simple configuration in which heavy metal is embedded in a via hole, and a current signal. Can be used for the input signal.
  • the material embedded in the via hole is Along with the input of the input signal, due to the tunnel magnetoresistance effect, spin precession occurs,
  • the third structure is The spin wave is excited in the first region by changing the magnetic anisotropy due to a leakage magnetic field from the spin or an inter-spin exchange interaction by the spin.
  • the information processing device can improve the energy efficiency when converting an electric signal and a spin wave by providing a magnetic tunnel junction element in the via hole.
  • a current signal can be used for the input / output.
  • An information processing device includes: The device further includes a current applying unit that applies a DC bias current to the second electrode.
  • the information processing device can accurately detect the spin movement in the output region by applying the DC bias current.
  • FIG. 1 is a diagram illustrating a configuration example of the information processing device 1 according to the present embodiment.
  • the information processing device 1 of the present embodiment forms a new spin wave (excitation and propagation) through the previous spin distribution state and the interaction of each signal, By detecting at this point and outputting a plurality of signals at the same time, a multi-input / multi-output type input / output configuration is realized and functions as a reservoir.
  • the information processing device 1 of the present embodiment is stacked on a garnet thin film 12 stacked on a conductive substrate 11 connected to a ground, and on the garnet thin film 12.
  • This device has a magnetoelectric coupling layer 13 and realizes a multi-input / multi-output type reservoir using a spin wave as a material wave.
  • a conventional neural network using a logic circuit requires a huge amount of memory to handle data that changes every moment, and it is difficult to reduce the circuit scale.
  • physical wiring must be performed, which causes a problem of wiring explosion, increases the circuit scale, and increases power consumption.
  • the information processing device of this embodiment is configured as a multi-input and other-output device based on the physical phenomenon of spin wave propagation, and has a function as a reservoir that determines the output based on the physical phenomenon that occurs with respect to the input. In addition to realizing this, low power consumption is realized while preventing an increase in scale.
  • the garnet thin film 12 is made of, for example, a ferrimagnetic material or a ferromagnetic material such as Tm 3 Fe 5 O 12 and Y 3 Fe 5 O 12 , and spin waves excited by the magnetoelectric coupling layer 13 in an input region to be described later. , Function as a transmission medium for propagation.
  • the magnetoelectric coupling layer 13 is made of, for example, a piezoelectric material or a ferroelectric material.
  • a surface 132 opposite to the interface 131 in contact with the garnet thin film 12 is an input / output surface for various signals (hereinafter, this surface is referred to as “input / output surface 132”). ").
  • the magnetoelectric coupling layer 13 has a structure in which a plurality of input electrodes 14 and a plurality of output electrodes 15 can be formed on the input / output surface 132.
  • the input electrode 14 and the output electrode 15 can be arranged in arbitrary regions on the input / output surface 132 by freely determining the size, number, and arrangement method.
  • the information processing device 1 according to the present embodiment can install a desired number of electrodes having a desired size at a desired position as long as it is within the plane of the input / output surface 132 except for physical limitations. .
  • an input electrode 14 and an output electrode 15 are searched so as to find an arrangement capable of obtaining the largest input / output variation and match the target computing content. It is desirable to arrange the electrodes while optimizing the position, size and number of the electrodes.
  • the input / output configuration of 100 inputs / 100 outputs is realized by the information processing device 1, 200 or more electrodes are provided on the input / output surface 132, and depending on the target computing content, 100 electrodes may be selected as the input electrode 14 and 100 electrodes may be selected and used as the output electrode 15 while searching for an arrangement capable of obtaining the largest number of input / output variations.
  • a large number of electrodes may be arranged in the input / output surface 132 in advance, and predetermined electrodes may be used as the input electrode 14 and the output electrode 15 in accordance with the target computing.
  • the output electrode 15 for example, more electrodes than the required number of outputs are assigned to the output electrode 15 and learning is performed while using an output signal from the electrodes in an external circuit, so that the error has a predetermined value. It is also possible to select a combination of lower electrodes as the output electrode 15 and not use it for the other electrodes. That is, the electrode actually used as the output electrode 15 may be selected from the initially set output electrode 15.
  • the material of the input electrode 14 and the output electrode 15 is arbitrary, and can be made of various metals such as copper (Cu), silver (Ag), and gold (Au).
  • An external circuit (not shown) is electrically connected to each input electrode 14 and output electrode 15, and an electric signal is supplied from the external circuit to the input electrode 14.
  • FIG. 1 shows an electrode arrangement example in which a predetermined number of input electrodes 14 and output electrodes 15 having a predetermined size are randomly arranged on the input / output surface 132. Further, for example, the input electrode 14 and the output electrode 15 of the present embodiment constitute the “first electrode” and the “second electrode” of the present invention, respectively.
  • the magnetoelectric coupling layer 13 When an electric signal is input to the input electrode 14 from an external circuit, the magnetoelectric coupling layer 13 has a property of an area (referred to as an “input area”) corresponding to the installation area of the input electrode 14 in the garnet thin film 12. Has a function to excite spin waves in the input region.
  • the spin wave excited in the input region propagates in the garnet thin film 12 to the installation region of the output electrode 15 in the garnet thin film 12 (hereinafter referred to as “output region”), and in the output region again the electric signal And output from the output electrode 15. That is, an output signal corresponding to the input signal is supplied to an external circuit (a circuit that executes various processes).
  • the information processing device 1 realizes a multi-input / multi-output input / output configuration without increasing the scale, and realizes low power consumption when performing reservoir computing. Can do.
  • the input area and the output area of the present embodiment correspond to the “first area” and the “second area” of the present invention, respectively.
  • the external magnetic field applied to the information processing device 1 of this embodiment will be described later.
  • FIG. 2A and 2B are diagrams illustrating a cross-sectional structure of the information processing device 1 in an installation region of the input electrode 14 and the output electrode 15 in the information processing device 1 of the present embodiment.
  • FIG. 2A is a diagram showing a cross-sectional structure when the method 1 is realized
  • FIG. 2B is a diagram showing a cross-sectional structure when the method 2 is realized.
  • a method of exciting a local spin wave in the input region without using a microstrip antenna is employed.
  • (1) A method of exciting a spin wave in an input region using the ME effect (electromagnetic effect) resulting from the interaction between the material constituting the magnetoelectric coupling layer 13 and the electron orbit of the material constituting the garnet thin film 12
  • (2) A method is adopted in which spin waves are excited by changing the uniaxial magnetic anisotropy of the input region by applying local distortion of the crystal to the input region of the garnet thin film 12 as a ferrimagnetic material.
  • the ME effect is a phenomenon in which the polarization changes when the spin direction changes, and the spin direction changes when the electric field changes.
  • the ME effect itself is well known, the details are omitted.
  • a magnetoelectric coupling layer 13 made of a ferroelectric is laminated on the garnet thin film 12, and the magnetoelectric coupling layer 13 is inserted.
  • the input electrode 14 and the output electrode 15 are provided on the output surface 132.
  • a voltage signal as an electrical signal (input signal) is input to the input electrode 14.
  • the spin wave excited in this way propagates in the garnet thin film 12 to the output region, and an interaction between the electron orbit of the magnetoelectric coupling layer 13 and the electron orbit of the garnet thin film 12 occurs in the output region,
  • the spin wave is converted into a voltage signal, and the voltage signal is output from the output electrode 15 as an output signal.
  • a magnetoelectric coupling layer 13 made of a piezoelectric material is laminated on the garnet thin film 12, and the input / output surface of the magnetoelectric coupling layer 13 is stacked.
  • An input electrode 14 and an output electrode 15 are provided on 132.
  • a voltage signal as an electrical signal (input signal) is input to the input electrode 14.
  • the crystal structure is distorted, the magnetic anisotropy of the crystal is changed, and the spin wave is excited and propagates to the output region.
  • the propagated spin wave causes an interaction between the garnet thin film 12 and the magnetoelectric coupling layer 13, and the spin wave is converted again into a voltage signal in the output region, and the voltage signal is output from the output electrode 15 as an output signal. Is done.
  • the material may have both the properties of a ferroelectric and a piezoelectric, but in either case, the spin wave is excited in the input region by the voltage signal and the propagated spin wave is It can be converted again into a voltage signal.
  • the information processing device 1 can perform mutual conversion between the voltage signal and the spin wave without mounting a large antenna, and thus can prevent the scale from increasing.
  • the structure of the magnetoelectric coupling layer 13 is not limited to the structure illustrated in FIGS. 2A and 2B.
  • the via hole 16 may be provided in the region immediately below the input electrode 14 and the output electrode 15, but details will be described in the section of the modification.
  • an external DC magnetic field may be applied to the information processing device 1 in order to excite spin waves that are asymmetric with respect to space and cause nonlinear interference.
  • each spin in the garnet thin film 12 is in the effective magnetic field when a relatively strong external DC magnetic field of about 0.1 to 0.2 T (Tesla) is applied to the + z-axis direction. Therefore, the spins are aligned in the z-axis direction, perform stable precession with a small cone angle, and clean linear interference of the spin wave excited by the magnetoelectric coupling layer 13 occurs. At this time, the inclination of each spin is about 0.1 to 0.2% as a component with respect to the in-plane direction.
  • each spin always has a wobbling effective magnetic field.
  • a very unstable rotational motion in which an effective magnetic field that changes from moment to moment is attempted to rotate, and the effective magnetic field changes at that time is continued.
  • the DC magnetic field applied to the information processing device 1 is (1) 0.03T (Tesla) in the + z direction, (2) 0.0001T in the + y direction, It was decided to adopt a configuration that excites and propagates spin waves that cause asymmetric and nonlinear interference.
  • a spin of about 3 to 10% is tilted in a component in the in-plane direction.
  • the generated spin wave can be excited.
  • the information processing device 1 of the present embodiment can excite spin waves that cause asymmetric and nonlinear interference in the garnet thin film 12 by applying an external DC magnetic field as shown in FIG. Diversity of output when computing is ensured.
  • the DC external magnetic field application mode (direction and magnitude) shown in FIG. 1 is merely an example, and the magnetic field applied to the information processing device 1 is determined according to the material used as the garnet thin film 12 and the magnetoelectric coupling layer 13. It is desirable to change.
  • a weak magnetic field in the + y direction as described above, it is possible to improve the characteristics (asymmetry and non-linear interference) of the excited spin wave and improve the performance as a reservoir.
  • the application of a magnetic field to itself is not an essential requirement of the present invention, and it is not always necessary to apply an external magnetic field in the + y direction if a spin wave that causes asymmetric and nonlinear interference can be excited.
  • the information processing device 1 of the present embodiment has a configuration in which an external DC magnetic field is applied by a module integrated with the information processing device 1 by using a conventional magnetic bubble technology.
  • this does not apply to a structure that applies an external DC magnetic field.
  • an external DC magnetic field can be individually applied to both the + z direction and the + y direction, but an 0.03 T external DC magnetic field is applied to the + z direction.
  • the external DC magnetic field can be applied to the information processing device 1 in the above-described manner by tilting (tilting) the application direction of the external DC magnetic field by 1 ° in the + y direction.
  • FIGS. 3A and 3B are diagrams for explaining simulation conditions in the present embodiment.
  • FIGS. 3A and 3B show the configuration of the garnet thin film 12 in the information processing device 1 for simulation, the relationship between the direction and intensity of the external magnetic field applied to the information processing device 1, and the excitation position of the spin wave in this simulation. It is a figure for demonstrating arrangement
  • Exciters 1 and 2 indicate spin wave excitation positions
  • Detectors 1, 2, and 3 indicate spin wave detection positions.
  • an information processing device 1 configured using a garnet thin film 12 having a planar structure of 20 ⁇ m ⁇ 20 ⁇ m ⁇ 100 nm was used.
  • a conductive substrate 11 is formed under the garnet thin film 12 shown in FIG. 3A and connected to the ground, and a magnetoelectric coupling layer 13 is laminated on the garnet thin film 12. ing.
  • the spin wave excited in the input region (Exciters 1 and 2) propagates in the inner region without being significantly attenuated and quickly attenuates when it propagates to the outer region.
  • the information processing device 1 Even if end face reflection occurs, no major problem occurs in the function as a reservoir. Therefore, as shown in FIG. 3A, it is essential to provide two regions with different damping constants in the garnet thin film 12. However, in this simulation, in order to remove the influence of the reflected wave, the information processing device 1 having the garnet thin film 12 having the configuration as shown in FIG. 3A is used.
  • simulation was performed with the following settings. (1) the saturation magnetization M S of garnet films 12, the entire area of 100 kA / m set to (2) exchange stiffness constant A EX, set to 3.7 ⁇ 10 -12 J / m ( 3) garnet films 12 Divide into small meshes having a volume of 10 nm ⁇ 10 nm ⁇ 50 nm along the Cartesian coordinate system (4) Set simulation temperature to 0K (5) Set almost all spin directions along + z direction (specifically, 99. 99%) After the initialization operation, the external DC magnetic field applied to the information processing device 1 is relaxed to 0.03T in the + z direction and 0.0001T in the + y direction as shown in FIG. 3B.
  • the spin direction is set in the + z direction.
  • this DC magnetic field is applied suddenly, the overall spin distribution changes, which may affect the simulation result. This is to prevent this.
  • the spin in a region other than the exciter is changed by a DC magnetic field, it is determined whether the observed phenomenon is a phenomenon caused by the application of a DC magnetic field or a phenomenon caused by the excitation / propagation of a spin wave. In order to prevent such a situation, the spin operation was prevented by the initialization operation in order to prevent such a situation.
  • intersection (0, 0) of the x axis and the y axis in FIG. 3A is the same as the coordinate (0, 0) of the intersection (0, 0) of the x axis and the y axis in FIG. 3B.
  • an input electrode 14 having a diameter of 250 nm is provided so that the center is aligned with the positions of Exciters 1 and 2 in FIG. 3B
  • an output electrode 15 having a diameter of 100 nm is provided so that the centers are aligned with the positions of Detectors 1, 2, and 3. .
  • input electrodes 14 corresponding to Exciters 1 and 2 are provided at positions (1 ⁇ m, 0) and ( ⁇ 1 ⁇ m, 0), respectively, and (0, 0) points are provided.
  • the output electrode 15 corresponding to the Detector 2 is provided at the position of Detector 2 at the position of Detector 2, at the position of (0, 1 ⁇ m), and at the position of (0, ⁇ 1 ⁇ m).
  • the area on the garnet thin film 12 corresponding to the installation area of the input electrode 14 provided at the positions of the Exciters 1 and 2 functions as the input area, and the installation of the output electrode 15 provided at the positions of the Detectors 1, 2, 3 is provided.
  • a region on the garnet thin film 12 corresponding to the region functions as the output region.
  • a voltage signal for spin wave excitation is input to the input electrode 14 with an external DC magnetic field applied (ie, 0.03 T in the + z direction and 0.0001 T in the + y direction).
  • an external DC magnetic field applied ie, 0.03 T in the + z direction and 0.0001 T in the + y direction.
  • FIG. 4A and 4B are diagrams for explaining the signals for spin wave excitation used in this simulation.
  • FIG. 4A is a diagram for explaining a spin wave excitation signal used when a spin wave is excited only once in the garnet thin film 12
  • FIG. 4B is a diagram illustrating a spin wave twice in the garnet thin film 12. It is a figure for demonstrating the signal for the spin wave excitation used when exciting.
  • the start position of the time axis (horizontal axis) is set to 0 point, and a scale is added to the horizontal axis every 1 ns (nanosecond).
  • single excitation signal a voltage signal for changing the uniaxial magnetic anisotropy Ku in the region of Exciter as shown in FIG. 4A (hereinafter referred to as “single excitation signal”) is used for input installed at the position of Exciter. Input to electrode 14.
  • the time length of the 1 st section for maintaining the uniaxial magnetic anisotropy Ku at Ku L is 3 ns (nanoseconds), and then the value of the uniaxial magnetic anisotropy Ku is maintained at Ku H.
  • the voltage value of the excitation signal was controlled once.
  • a voltage signal (hereinafter referred to as “twice excitation signal”) for changing the uniaxial magnetic anisotropy Ku in a two-step format as shown in FIG. 4B is installed at the position of Exciter. Input to the input electrode 14.
  • the change in the uniaxial magnetic anisotropy Ku shown in FIGS. 4A and 4B is a change in the input region, and the uniaxial magnetic anisotropy Ku is always maintained at Ku H in a region other than the region corresponding to Exciter.
  • FIG. 5 shows the spatial distribution of spin waves detected in the areas of Detectors 1, 2, and 3 when an excitation signal is input once to the input electrode provided in Exciter 1 in the simulation of this embodiment.
  • FIG. 5 is a diagram showing the spatial distribution of the sx component and a diagram showing the spatial distribution of the sy component.
  • the vertical and horizontal sizes are each 10 ⁇ m
  • the spatial distribution in a region of 10 ⁇ m ⁇ 10 ⁇ m is shown, and a scale is added to each of the x-axis and y-axis for every 1 ⁇ m.
  • the position of Excitter 1 is indicated by a black star, and the values of the sx component and the sy component are defined by color bars.
  • the method of detecting the spin wave in the output regions of the detectors 1, 2, and 3 is arbitrary.
  • the spin wave may be detected based on the voltage signal output from the output electrode 15. You may make it detect by another method.
  • the amplitude of the spin wave excited in this case has an asymmetric propagation characteristic rather than spatially symmetrical with respect to the excitation location (that is, Exciter 1).
  • a region with a large amplitude was generated in a direction slightly inclined with respect to the horizontal direction of the drawing, and a region with a large amplitude was not generated above and below.
  • FIG. 6 is a diagram showing a spatial distribution of spin waves excited when an excitation signal is input twice to the input electrodes provided in the Exciters 1 and 2 in the simulation of the present embodiment. “3”, a diagram showing the spatial distribution of the sx component at the timing when 7 ns has elapsed after the start of signal input, and a diagram showing the spatial distribution of the sx component at the timing when the X value is “4” and 8 ns have elapsed after starting the signal input It is. Note that FIG. 6 is graduated every 1 ⁇ m in the range of 10 ⁇ m square as in FIG.
  • FIG. 7 is a diagram showing temporal changes in the sx component and sz component of the spin wave.
  • a diagram showing the change state of the uniaxial magnetic anisotropy Ku in the regions of Exciters 1 and 2 a diagram showing the change over time of the sx component and the sz component in the region of Exciter 1
  • the sx component is indicated by a red line
  • the sz component is indicated by a blue line.
  • FIG. 8 shows the sx component of the spin wave detected in the areas of Detectors 1, 2, and 3 when the excitation signal is input twice to the input electrodes corresponding to Exciters 1 and 2 in the simulation of this embodiment. It is a figure which shows an envelope.
  • the left diagram of FIG. 8 shows the sx component temporal change and envelope of the spin wave observed when the elapsed time t is “8 to 9 ns” with the X value set to “1.5 ns”.
  • 8 shows the relationship between the change in the sx component and the envelope observed when the elapsed time t is “8 to 9 ns” when the X value is set to “4.5 ns”. Show.
  • the sx component is indicated by a red line
  • the envelope is indicated by a black line.
  • the spin waves excited in the areas of Exciters 1 and 2 propagate in the garnet thin film 12 and are detected in the areas of Detectors 1, 2, and 3. If linear interference occurs, The detection results at Detectors 1 and 3 that are equidistant from Exciters 1 and 2 should match.
  • FIG. 7 there are two timings during which the uniaxial magnetic anisotropy Ku in the exciter steps from Ku L ⁇ Ku H during this simulation time. It can be seen from FIG. 7 that the spin wave excited at the first step and the spin wave excited at the second step are different in each of the Exciter, Detectors 1, 2, and 3.
  • spin waves are excited and propagated in a state where the spin in the region other than the exciter is oriented substantially perpendicular to the surface (+ z direction), and corresponds to each detector. Reach the area you want.
  • the spin wave propagates in a state where the spin is already distributed to some extent by the propagated spin wave (that is, the spin is shaken or tilted). In this case, a difference occurs in the propagation environment between the spin wave excited in the first time and the spin wave excited in the second time.
  • This phenomenon suggests that the spin wave excited in the second step is affected by the spin wave excited in the first step. That is, this phenomenon has a history in the spin of the garnet thin film 12 due to the excitation and propagation of the spin wave excited by the first step, and this history affects the spin wave excited by the second step. It means that
  • the spin In a magnetic material having a spontaneous spin in which the size of an atom is not zero, the spin always points in some direction.
  • the current spin interacts with the input signal field (vector) and the incoming spin wave to determine the spin movement of the atom, and the spin wave is excited and propagated.
  • the current spin state determined by the history of excitation and propagation of the spin wave in the past determines the interaction with the signal field.
  • the information processing device 1 changes an output signal according to a history of input signals input in the past.
  • a new spin wave can be formed through the interaction of each signal, it is highly adaptable even when performing operations that calculate the weighted sum of past memories without using a memory. Can do.
  • the information processing device 1 of this embodiment can be used as a reservoir that can ensure high adaptability to the neural network without increasing the scale.
  • the garnet thin film 12 has a characteristic that spin characteristics (for example, spin direction and distribution) differ depending on the position, in the information processing device 1 of the present embodiment, from the output region.
  • the output electrical signal changes in accordance with the in-plane positions of the input electrode 14 and the output electrode 15 on the input / output surface 132.
  • the information processing device 1 of the present embodiment outputs a different signal if the in-plane position of the output region is different.
  • the history of spin waves excited and propagated based on past input signals is reflected in the output signal. Even when the same signal is input from and the signals are output from the same in-plane position, different signals are output.
  • the information processing device 1 of the present embodiment can realize a wide variety of output variations with respect to a large number of input signals, so that it can be used as a highly adaptable reservoir even when realizing a neural network. Can do.
  • FIG. 9 is a diagram showing a simulation result of the reservoir computing using the information processing device of the present embodiment.
  • a plurality of types of twice-excitation signals having different X values are input to the input electrode 14 corresponding to Exciter to excite spin waves that cause nonlinear interference. This is a simulation when the X value of each input signal is estimated by an external circuit using the excited spin wave.
  • the output signal output from the output electrode 15 corresponding to each detector is output to the external circuit for 1 ns from the timing when the elapsed time t from the input start timing of the twice excitation signal becomes 8 ns to 9 ns. Based on the output signal, the external circuit was made to learn the X value estimation method.
  • a double excitation signal whose X value is unknown (specifically, a double excitation in which the X value is “2.0 ns”, “3.0 ns”, “4.0 ns”) Signal) is input to the input electrodes 14 corresponding to Exciters 1 and 2, and the external circuit estimates the X value based on the output signal.
  • FIG. 9 is a diagram showing a simulation result of the reservoir computing using the information processing device 1 of the present embodiment.
  • the X value of the actually input double excitation signal is shown on the horizontal axis, and the external circuit determines from the output signal.
  • the estimated X value is set on the vertical axis.
  • the diagonal line extending from the zero point is a line connecting the points where the X value in the actually inputted double excitation signal and the X value estimated from the output signal coincide with each other. The closer it is, the smaller the error between the actual X value and the estimated X value is.
  • the estimation result based on the training data is indicated by a blue square
  • the estimation result of the X value when a double excitation signal with an unknown X value is input is indicated by a red circle.
  • the information processing device 1 can convert (mapping) a signal into a high-dimensional space, and when learning is successful in an external circuit using the output, and an unlearned signal is input
  • the generalization ability that can estimate the most probable value with high accuracy can be realized.
  • the information processing device 1 of the present embodiment can realize high-precision estimation with an external circuit even when an unknown signal is input.
  • This generalization capability is a feature of reservoir computing, and even when an unlearned signal is input, conversion (mapping) to a high-dimensional space effective for successful parameter / fitting in an external circuit is realized. Capable functions are required.
  • the information processing device 1 of the present embodiment can be mapped to a high-dimensional space that can realize reservoir computing with high accuracy.
  • FIG. 10A and FIG. 10B are diagrams showing simulation results of the present embodiment.
  • FIG. 10A is a diagram showing a distribution of RMSE when an excitation signal is input twice to the input electrodes corresponding to Exciters 1 and 2, and
  • FIG. 10B shows the input electrode 14 corresponding to Exciter 1.
  • RMSE Root Mean Square Errors: the root mean square error
  • the present simulation changes the conditions in FIG. 9 (that is, the conditions in which the exciters 1 and 2 are simultaneously excited with spin waves and the elapsed time t is 8 to 9 ns) while changing the external circuit. It is a simulation at the time of estimating the X value of an input signal.
  • the RMSE is calculated based on the X value estimated from the output signal and the X value in the actually input double excitation signal, and the relationship between the RMSE calculation result and the start timing and duration is plotted. The result as shown in FIG. 10A was obtained.
  • the RMSE is calculated based on the X value estimated by the external circuit and the X value corresponding to the actual input signal while changing the start timing and duration.
  • the result as shown in FIG. 10B was obtained.
  • the information processing device 1 of the present embodiment that can excite spin waves that cause asymmetric and nonlinear interference has high adaptability to reservoir computing.
  • Modification 1 In the above embodiment, the configuration in which the information processing device 1 alone converts and outputs an input signal has been described. However, in order to realize a neural network, a single system (that is, reservoir computing is realized in combination with an external circuit). System).
  • FIG. 11 is a diagram showing the configuration of the information processing device 1 in the present modification
  • FIGS. 12A to 12C, FIGS. 13A and 13B are cross-sectional views showing the configuration inside the via hole.
  • each via hole 16 has a configuration in which another material is embedded to form an element. Further, as a specific configuration in the via hole 16, five configurations as shown in FIGS. 12A to 12C and FIGS. 13A and 13B can be adopted.
  • ⁇ Configuration pattern 1> In this configuration, as shown in FIG. 12A, an insulating film is provided in a portion in contact with the magnetoelectric coupling layer 13 in the via hole 16, and a ferroelectric is embedded in a region held by the insulating film.
  • ⁇ Configuration pattern 2> In this configuration, as shown in FIG. 12B, an insulating film is provided in a portion in contact with the magnetoelectric coupling layer 13 in the via hole 16, and a piezoelectric body is embedded in a region held by the insulating film.
  • ⁇ Configuration pattern 3> In this configuration, as shown in FIG. 12C, in the via hole 16, an insulating film is provided at a portion in contact with the magnetoelectric coupling layer 13, and an inverse magnetostrictive ferromagnetic material and a piezoelectric material are laminated in a region held by the insulating film. And embedded.
  • the spin wave is excited by using magnetic interaction or local electron interaction.
  • This configuration makes it possible to improve the energy efficiency when the voltage signal and the spin wave are mutually converted.
  • ⁇ Configuration pattern 4> In this configuration, as shown in FIG. 13A, an insulating film is provided in a portion in contact with the magnetoelectric coupling layer 13 in the via hole 16, and a region held by the insulating film is filled with heavy metal.
  • an isolation wall made of an insulating film is provided in a region held by the insulating film.
  • tantalum (Ta), tungsten (W), platinum (Pt), or the like can be used as the heavy metal.
  • Heavy metals can generate spin-polarized electron current because of their large spin-orbit interaction.
  • the spin wave is excited and propagated by changing the direction of the spin flowing on the surface of the garnet thin film 12 according to the direction of the current flowing through the heavy metal, and a voltage signal is output from the output electrode 15.
  • the conversion efficiency between the ferromagnetic material and the piezoelectric material that propagates the spin wave can be increased, and the energy efficiency when the electrical signal and the spin wave are mutually converted can be improved.
  • ⁇ Configuration pattern 5> In this configuration, as shown in FIG. 13B, in the via hole 16, an insulating film is provided in a portion in contact with the magnetoelectric coupling layer 13, and a ferromagnetic material, a tunnel magnetic film, and a metal wiring are provided in a region held by the insulating film. It is the structure which laminates
  • the spin wave can be excited by the ferromagnetic tunnel junction.
  • the ferromagnetic tunnel junction is an element having a three-layer structure composed of a ferromagnetic material, a tunnel insulating film, and a ferromagnetic material, the resistance of which changes depending on the spin direction of the upper and lower magnetic materials.
  • the input electrode 14 and the output electrode 15 must each be composed of two terminals.
  • the spin of the ferromagnet below the tunnel junction precesses depending on the direction of the current by utilizing magnetic interaction or local electron interaction, and the leakage magnetic field from this spin
  • the garnet thin film 12 receives the exchange interaction between the spins beyond the layer, the spin wave is excited and propagated, and a current signal is output from the output electrode 15.
  • the information processing device 1 is configured by the garnet thin film 12.
  • any material that can induce ferromagnetic resonance and spin waves such as a ferromagnetic metal alloy, a ferromagnetic oxide, and a ferrimagnetic material,
  • the information processing device 1 may be configured using anything.

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Abstract

In the present invention, a garnet thin film (12) is laminated on an electrically conductive substrate (11) connected to ground, a magnetoelectric coupling layer (13) is provided on the garnet thin film, and in the magnetoelectric coupling layer, the surface on the side opposite to an interface (131) in contact with the garnet thin film is an input/output surface (132). On the input/output surface, provided are a plurality of input electrodes (14) and a plurality of output electrodes (15) for which quantity, size, and placement position can be set freely. Provided is a multi-input, multi-output information processing device for which, when a prescribed electric signal is input as an input signal to an input electrode, a spin wave is excited in an input region corresponding to the input electrodes, and spin waves are propagated in an output region corresponding to the output electrodes, and by converting the spin waves to electric signals again in the output region, and outputting from the output electrode, it is possible to realize low power consumption while preventing an increase in scale.

Description

情報処理デバイスInformation processing device
　本発明は、信号の情報処理デバイスに関し、特に多入力・多出力の入出力形態を実現可能な情報処理デバイスに関する。 The present invention relates to a signal information processing device, and more particularly to an information processing device capable of realizing a multi-input / multi-output input / output configuration.
　近年、ＣＭＯＳ（Ｃｏｍｐｌｅｍｅｎｔａｒｙ　Ｏｘｉｄｅ　Ｓｅｍｉｃｏｎｄｕｃｔｏｒ）集積回路技術によるデジタルロジック回路を用いた従来型のコンピューティングでは、時間的、エネルギー的な計算コストがかかる各種の情報処理を低コストに実現するため、ニューロモルフィックコンピューティング（ニューラルネットワークともいう。）を用いる方法が提案されている。 In recent years, in conventional computing using digital logic circuits based on CMOS (Complementary Oxide Semiconductor) integrated circuit technology, various types of information processing that requires time and energy calculation costs are realized at low cost. A method using computing (also called a neural network) has been proposed.
　例えば、認知処理や連想記憶等の情報処理においては、ニューラルネットワークを用いることによる優位性が存分に発揮されることが望まれている。また、例えば、自動車の自動運転等の分野においては、イメージセンサと連動した深層学習を用いて、認知処理等の高度な処理を行う必要があり、計算コストが非常に大きくなる。このため、この種の処理に、計算コストの非常に小さいニューラルネットワークを活用するための研究が積極的に進められている。 For example, in information processing such as cognitive processing and associative memory, it is desired that superiority by using a neural network is fully exhibited. In addition, for example, in the field of automatic driving of automobiles, it is necessary to perform advanced processing such as cognitive processing using deep learning in conjunction with an image sensor, and the calculation cost becomes very high. For this reason, research for utilizing a neural network with a very low calculation cost for this type of processing is being actively promoted.
　従来、ニューラルネットワークを実現する手法の１つとして、デジタルロジック回路を用いて、脳の機能を模倣したデバイスが提案されている（例えば、特許文献１）。 Conventionally, as one method for realizing a neural network, a device that imitates the function of a brain using a digital logic circuit has been proposed (for example, Patent Document 1).
　しかしながら、上記特許文献１に記載のデバイスのように従来型のデジタルロジック回路により、多入力及び多出力であるニューロン型の入出力形態を実現しようとすると、微小領域での配線が困難になり、いわゆる、配線爆発問題として、装置製造が困難になることが多い。 However, if a neuron-type input / output configuration having multiple inputs and multiple outputs is realized by a conventional digital logic circuit like the device described in Patent Document 1, wiring in a micro area becomes difficult, As a so-called wiring explosion problem, it is often difficult to manufacture the device.
　また、このようなデジタルロジック回路は、配線の１つ１つをＯＮ／ＯＦＦするためのスイッチング素子（例えば、ＭＯＳＦＥＴ）を配線毎に設ける必要性があるため、回路構成が大規模化してしまう。 In addition, since such a digital logic circuit needs to be provided with a switching element (for example, a MOSFET) for turning on / off each of the wirings for each wiring, the circuit configuration becomes large.
　さらに、デジタルロジック回路の場合において、電気配線によるデータの読み出し／書き込みは、その性質上、１配線あたり１クロックとする必要性があるため、入出力数が増加すると、それに応じて必要な動作クロック数が増加し、エネルギー消費量が増大してしまう。 Furthermore, in the case of a digital logic circuit, data reading / writing by electrical wiring needs to be one clock per wiring due to its nature. Therefore, when the number of inputs / outputs increases, an operation clock required accordingly The number increases and energy consumption increases.
　したがって、上記特許文献１の構成において、回路規模の縮小と、低消費電力化を両立することは、困難である。 Therefore, in the configuration of Patent Document 1, it is difficult to achieve both reduction in circuit scale and reduction in power consumption.
　本発明は、入力に対して発生する物理現象に基づいて出力を決定するリザバーを実現するためのデバイスであって、規模の増大を防止しつつ、低消費電力化を実現可能な多入力・多出力型の情報処理デバイスを提供することにある。 The present invention is a device for realizing a reservoir that determines an output based on a physical phenomenon that occurs with respect to an input, and is capable of reducing power consumption while preventing an increase in scale. It is to provide an output type information processing device.
　本発明は、
　基準電圧に維持される第１構造層と、
　前記第１構造層上に形成される第２構造層と、
　前記第２構造層上に形成され、前記第２構造層に接する面と反対側の面が信号の入出力面となる第３構造層と、
　を有し、
　前記第３構造層が、
　　前記入出力面のいずれの場所にも形成可能な電極であって、所定の電気信号が入力信号として入力される１以上の第１電極と、
　　前記第１電極が形成された場所を除き、前記入出力面のいずれの場所にも形成可能な電極であって、所定の電気信号が出力信号として出力される１以上の第２電極と、
　を備え、
　前記第２構造層が、
　　前記第１電極に対して所定の電気信号が入力信号として入力された場合に、前記第１電極に対応する第１領域にてスピン波を励起し、かつ、前記第２電極に対応する第２領域に前記スピン波を伝搬させる構造を有し、
　前記第１領域と前記第２領域の位置に応じて、前記スピン波の特性が異なることを特徴とする。 The present invention
A first structural layer maintained at a reference voltage;
A second structural layer formed on the first structural layer;
A third structural layer formed on the second structural layer, the surface opposite to the surface in contact with the second structural layer being a signal input / output surface;
Have
The third structure layer is
One or more first electrodes that can be formed at any place on the input / output surface, and a predetermined electrical signal is input as an input signal;
One or more second electrodes that can be formed at any location on the input / output surface except for the location where the first electrode is formed, and that output a predetermined electrical signal as an output signal;
With
The second structural layer comprises:
When a predetermined electrical signal is input as an input signal to the first electrode, a spin wave is excited in the first region corresponding to the first electrode, and a second corresponding to the second electrode Having a structure for propagating the spin wave in a region;
The spin waves have different characteristics depending on the positions of the first region and the second region.
図１は、本発明に係る一実施形態における情報処理デバイスの一構成例を示す構成図である。FIG. 1 is a block diagram showing a configuration example of an information processing device according to an embodiment of the present invention. 図２Ａは、一実施形態の情報処理デバイスにおける入力領域及び出力領域の断面構造の一例を示す図である。FIG. 2A is a diagram illustrating an example of a cross-sectional structure of an input region and an output region in the information processing device according to the embodiment. 図２Ｂは、一実施形態の情報処理デバイスにおける入力領域及び出力領域の断面構造の一例を示す図である。FIG. 2B is a diagram illustrating an example of a cross-sectional structure of an input region and an output region in the information processing device according to the embodiment. 図３Ａは、一実施形態において実行されるシミュレーションの条件（シミュレーション条件）を説明するための図である。FIG. 3A is a diagram for describing a condition (simulation condition) of a simulation executed in one embodiment. 図３Ｂは、一実施形態において実行されるシミュレーションの条件（シミュレーション条件）を説明するための図である。FIG. 3B is a diagram for explaining a condition (simulation condition) of a simulation executed in one embodiment. 図４Ａは、一実施形態においてシミュレーションに用いたスピン波励起用の信号を説明するための図である。FIG. 4A is a diagram for describing a spin wave excitation signal used for simulation in one embodiment. 図４Ｂは、一実施形態においてシミュレーションに用いたスピン波励起用の信号を説明するための図である。FIG. 4B is a diagram for explaining a spin wave excitation signal used for simulation in one embodiment. 図５は、一実施形態のシミュレーションにおいて、Ｅｘｃｉｔｅｒ１に設けられた入力用電極に１回励起信号を入力した場合に、各Ｄｅｔｅｃｔｏｒの領域にて検出されたスピン波の空間分布を示す図である。FIG. 5 is a diagram illustrating a spatial distribution of spin waves detected in each Detector region when an excitation signal is input once to an input electrode provided in the Exciter 1 in a simulation according to an embodiment. 図６は、一実施形態のシミュレーションにおいてＥｘｃｉｔｅｒ１及び２に設けられた入力用電極に対して２回励起信号を入力した際に励起されるスピン波の空間分布を示す図である。FIG. 6 is a diagram illustrating a spatial distribution of spin waves that are excited when an excitation signal is input twice to the input electrodes provided in the Exciters 1 and 2 in the simulation of the embodiment. 図７は、一実施形態のシミュレーションにおけるスピン波のｓｘ成分及びｓｚ成分の経時変化を示す図である。FIG. 7 is a diagram illustrating temporal changes of the sx component and the sz component of the spin wave in the simulation of the embodiment. 図８は、一実施形態のシミュレーションにおいてＥｘｃｉｔｅｒ１及び２に対応する入力用電極に２回励起信号を入力した場合に、各Ｄｅｔｅｃｔｏｒの領域において検出されるスピン波のｓｘ成分とその包絡線を示す図である。FIG. 8 is a diagram illustrating an sx component and an envelope of a spin wave detected in each detector region when an excitation signal is input twice to the input electrodes corresponding to Exciters 1 and 2 in the simulation of one embodiment. It is. 図９は、一実施形態の情報処理デバイスを用いたリザバーコンピューティングのシミュレーション結果を示す図である。FIG. 9 is a diagram illustrating a simulation result of the reservoir computing using the information processing device according to the embodiment. 図１０Ａは、一実施形態のシミュレーション結果を示す図である。FIG. 10A is a diagram illustrating a simulation result of one embodiment. 図１０Ｂは、一実施形態のシミュレーション結果を示す図である。FIG. 10B is a diagram illustrating a simulation result according to an embodiment. 図１１は、本発明の変形例２における情報処理デバイスの構成を示す図である。FIG. 11 is a diagram showing a configuration of an information processing device in Modification 2 of the present invention. 図１２Ａは、変形例２におけるビアホール内部の構成例を示す断面図である。FIG. 12A is a cross-sectional view illustrating a configuration example inside the via hole in the second modification. 図１２Ｂは、変形例２におけるビアホール内部の構成例を示す断面図である。FIG. 12B is a cross-sectional view illustrating a configuration example inside the via hole in the second modification. 図１２Ｃは、変形例２におけるビアホール内部の構成例を示す断面図である。FIG. 12C is a cross-sectional view illustrating a configuration example inside the via hole in the second modification. 図１３Ａは、変形例２におけるビアホール内部の構成例を示す断面図である。FIG. 13A is a cross-sectional view illustrating a configuration example inside a via hole in Modification 2. 図１３Ｂは、変形例２におけるビアホール内部の構成例を示す断面図である。FIG. 13B is a cross-sectional view illustrating a configuration example inside the via hole in the second modification.
　（１）本発明の一実施形態に係る情報処理デバイスは、
　基準電圧に維持される第１構造層と、
　前記第１構造層上に形成される第２構造層と、
　前記第２構造層上に形成され、前記第２構造層に接する面と反対側の面が信号の入出力面となる第３構造層と、
　を有し、
　前記第３構造層が、
　　前記入出力面のいずれの場所にも形成可能な電極であって、所定の電気信号が入力信号として入力される１以上の第１電極と、
　　前記第１電極が形成された場所を除き、前記入出力面のいずれの場所にも形成可能な電極であって、所定の電気信号が出力信号として出力される１以上の第２電極と、
　を備え、
　前記第２構造層が、
　　前記第１電極に対して所定の電気信号が入力信号として入力された場合に、前記第１電極に対応する第１領域にてスピン波を励起し、かつ、前記第２電極に対応する第２領域に前記スピン波を伝搬させる構造を有し、
　前記第１領域と前記第２領域の位置に応じて、前記スピン波の特性が異なる構成を有している。 (1) An information processing device according to an embodiment of the present invention includes:
A first structural layer maintained at a reference voltage;
A second structural layer formed on the first structural layer;
A third structural layer formed on the second structural layer, the surface opposite to the surface in contact with the second structural layer being a signal input / output surface;
Have
The third structure layer is
One or more first electrodes that can be formed at any place on the input / output surface, and a predetermined electrical signal is input as an input signal;
One or more second electrodes that can be formed at any location on the input / output surface except for the location where the first electrode is formed, and that output a predetermined electrical signal as an output signal;
With
The second structural layer comprises:
When a predetermined electrical signal is input as an input signal to the first electrode, a spin wave is excited in the first region corresponding to the first electrode, and a second corresponding to the second electrode Having a structure for propagating the spin wave in a region;
The spin wave characteristics are different depending on the positions of the first region and the second region.
　この構成により、本発明の一実施形態に係る情報処理デバイスは、第３構造層に形成される第１電極及び第２電極の少なくともいずれか一方の配置位置が異なれば、同一の信号を第１電極に入力したとしても、異なる信号を第２電極から取り出すことができるので、入出力面に複数の第１電極（入力用電極）及び第２電極（出力用電極）を形成した場合にも、それぞれの入力信号に対して、異なる信号を出力することができる。 With this configuration, the information processing device according to the embodiment of the present invention outputs the same signal as the first signal if the arrangement position of at least one of the first electrode and the second electrode formed in the third structure layer is different. Even if it is input to the electrode, a different signal can be extracted from the second electrode, so even when a plurality of first electrodes (input electrodes) and second electrodes (output electrodes) are formed on the input / output surface, Different signals can be output for each input signal.
　すなわち、本発明の一実施形態に係る情報処理デバイスは、ロジック回路を用いることなく、入出力面内に入力電極と出力電極を適切に設置するだけで、入力電極及び出力電極の面内位置に応じて、入力信号を適切に処理しつつ、出力することができる。 That is, the information processing device according to an embodiment of the present invention can be placed in the in-plane positions of the input electrode and the output electrode by appropriately installing the input electrode and the output electrode in the input / output surface without using a logic circuit. Accordingly, the input signal can be output while being appropriately processed.
　したがって、本発明の一実施形態に係る情報処理デバイスは、電気配線によらず、かつ、動作クロックに無関係など電子のチャージ及びディスチャージによる電位変化を利用することなく、スピン波の伝搬という物理現象によって多入力及び多出力のデバイスとして構成することができる。 Therefore, the information processing device according to an embodiment of the present invention is based on a physical phenomenon of spin wave propagation without using electric wiring and without using a potential change due to charge and discharge of electrons, such as regardless of an operation clock. It can be configured as a multi-input and multi-output device.
　この結果、本発明の一実施形態に係る情報処理デバイスは、入力に対して発生する物理現象に基づいて出力を決定するリザバーにおいて、規模の増大を防止しつつ、低消費電力化を実現可能な多入力・多出力型の情報処理デバイスを実現することができる。 As a result, the information processing device according to an embodiment of the present invention can achieve low power consumption while preventing an increase in scale in a reservoir that determines an output based on a physical phenomenon that occurs with respect to the input. A multi-input / multi-output type information processing device can be realized.
　そして、本発明の一実施形態に係る情報処理デバイスは、入力信号の順序やアナログデータの入力信号波形、あるいは、多入力の組み合わせに依存して、多種多様な出力バリエーションを実現することができるので、ニューラルネットワークなどの多数の情報処理を実現するためのデバイスとして用いることができる。 The information processing device according to an embodiment of the present invention can realize a wide variety of output variations depending on the order of input signals, the input signal waveform of analog data, or a combination of multiple inputs. It can be used as a device for realizing a large number of information processing such as a neural network.
　（２）また、本発明の一実施形態に係る情報処理デバイスは、
　前記入出力面の任意方向に対して、所定値の直流外部磁場を印加する磁場印加手段をさらに備える構成を有している。 (2) Further, an information processing device according to an embodiment of the present invention includes:
It has a configuration further comprising magnetic field applying means for applying a DC external magnetic field having a predetermined value in an arbitrary direction of the input / output surface.
　この構成により、本発明の一実施形態に係る情報処理デバイスは、入力領域内の原子が有するスピンに対して、任意方向の磁場を印加することができるので、例えば、非線形干渉が発生し易くなるなどの所定の特性を有するスピン波を励起することができる。 With this configuration, the information processing device according to an embodiment of the present invention can apply a magnetic field in an arbitrary direction to the spins of the atoms in the input region. For example, nonlinear interference is likely to occur. It is possible to excite spin waves having predetermined characteristics such as.
　すなわち、本発明の一実施形態に係る情報処理デバイスは、多数の入力があった場合にはスピン波の伝搬過程で事前のスピン分布状態やスピン波同士の干渉など、相互作用を用いることによって、多入力・多出力型の情報処理デバイスを実現することができる。 That is, the information processing device according to an embodiment of the present invention uses an interaction such as a prior spin distribution state or interference between spin waves in a spin wave propagation process when there are a large number of inputs. A multi-input / multi-output type information processing device can be realized.
　また、この構成により、本発明の一実施形態に係る情報処理デバイスは、空間に対して非対称な外部磁場環境を設定することも可能であり、かつ、非線形干渉が生じるスピン波を第２構造層の入力領域にて励起させることができるので、入力信号に対する出力の多様性を確保することができるとともに、ニューラルネットワークに相当する機能を実現する際においても、高い適応性を確保することができる。 Also, with this configuration, the information processing device according to an embodiment of the present invention can set an external magnetic field environment that is asymmetric with respect to space, and can generate spin waves that cause nonlinear interference in the second structure layer. Therefore, it is possible to ensure the diversity of output with respect to the input signal and also to ensure high adaptability when realizing the function corresponding to the neural network.
　（３）また、本発明の一実施形態に係る情報処理デバイスは、
　前記入力信号が入力され、前記スピン波が前記第２構造層を伝搬した場合に、
　その履歴がスピンの分布状態として残留し、その後に入力される前記入力信号に対する前記出力信号の信号値を前記履歴に基づき変化させる、構成を有している。 (3) Moreover, an information processing device according to an embodiment of the present invention includes:
When the input signal is input and the spin wave propagates through the second structure layer,
The history remains as a spin distribution state, and the signal value of the output signal with respect to the input signal input thereafter is changed based on the history.
　この構成により、直前に入力された信号が、第２構造層におけるスピンの分布状態として残留するので、次に信号が入力され、スピン波が励起されると、当該スピン波が、スピンの分布状態が変化した環境下を伝播し、当該入力信号に対応する出力信号が変化することとなる。 With this configuration, since the signal input immediately before remains as the spin distribution state in the second structure layer, when the signal is input next and the spin wave is excited, the spin wave is converted into the spin distribution state. Is propagated under an environment where the change occurs, and the output signal corresponding to the input signal changes.
　この結果、本発明の一実施形態に係る情報処理デバイスは、過去に入力された入力信号の履歴に応じて、出力信号を変化させることができるとともに、各信号の相互作用を通して、新たなスピン波を形成することができるので、メモリを併設することなく、過去の記憶の重み付け総和をとる演算を行う際にも、高い適応性を発揮することができる。 As a result, the information processing device according to the embodiment of the present invention can change the output signal according to the history of the input signal input in the past, and can generate a new spin wave through the interaction of each signal. Therefore, it is possible to exhibit high adaptability even when performing an operation for obtaining a weighted sum of past memories without providing a memory.
　特に、時系列データでは、前後のデータ間に相関関係がある可能性が高いので、本発明の一実施形態に係る情報処理デバイスは、データ間の相関関係を反映した出力特性を実現できる。 In particular, in time-series data, there is a high possibility that there is a correlation between the preceding and succeeding data. Therefore, the information processing device according to an embodiment of the present invention can realize output characteristics reflecting the correlation between the data.
　なお、時間的に連続するアナログデータにおいても直前の入力信号値や直後の入力信号値と、現在の入力信号値の間には相関関係（例えば、時間的・数値的連続性）があるので、前後の信号値を反映した出力特性を実現できる。 Note that there is a correlation (for example, temporal / numerical continuity) between the immediately preceding input signal value or the immediately following input signal value and the current input signal value even in time-sequential analog data. Output characteristics reflecting the signal values before and after can be realized.
　（４）また、本発明の一実施形態に係る情報処理デバイスは、
　前記第３構造層が、
　　前記第１電極及び前記第２電極の形成された領域にビアホールを有し、当該ビアホール内に他の部位とは組成の異なる材料が埋め込まれている、構成を有している。 (4) Moreover, an information processing device according to an embodiment of the present invention includes:
The third structure layer is
The region where the first electrode and the second electrode are formed has a via hole, and the via hole is filled with a material having a composition different from that of other portions.
　この構成により、本発明の一実施形態に係る情報処理デバイスは、電気信号とスピン波を変換する際のエネルギー効率を向上させることができる。 With this configuration, the information processing device according to an embodiment of the present invention can improve energy efficiency when converting an electric signal and a spin wave.
　（５）また、本発明の一実施形態に係る情報処理デバイスは、
　前記第３構造層が、
　　前記入力信号の入力に伴い変形し、
　前記第２構造層が、
　　前記第３構造層の変形に伴って、前記第１領域の磁気異方性が変化することにより前記第１領域にて前記スピン波が励起される、構成を有している。 (5) Moreover, an information processing device according to an embodiment of the present invention includes:
The third structure layer is
Deformed with the input of the input signal,
The second structural layer comprises:
The spin wave is excited in the first region by changing the magnetic anisotropy of the first region in accordance with the deformation of the third structure layer.
　この構成により、本発明の一実施形態に係る情報処理デバイスは、圧電体により第３構造層を構成することで、第１領域にてスピン波を励起することができるので、情報処理デバイスの構成を簡略化できるとともに、ビアホール内に圧電体を埋め込む構成とすれば、電気信号とスピン波相互間の変換効率を向上させることができる。 With this configuration, the information processing device according to the embodiment of the present invention can excite spin waves in the first region by configuring the third structure layer with the piezoelectric body. If the piezoelectric material is embedded in the via hole, the conversion efficiency between the electric signal and the spin wave can be improved.
　（６）また、本発明の一実施形態に係る情報処理デバイスは、
　前記第３構造層が、
　　前記入力信号の入力に伴い、分極ベクトルが変化し、
　前記第２構造層が、
　　前記第３構造層における分極ベクトルの変化に伴って生じる電気磁気効果に起因して磁気異方性が変化することにより前記第１領域にて前記スピン波が励起される、構成を有している。 (6) Moreover, an information processing device according to an embodiment of the present invention includes:
The third structure layer is
With the input of the input signal, the polarization vector changes,
The second structural layer comprises:
The spin wave is excited in the first region by a change in magnetic anisotropy due to an electromagnetic effect caused by a change in polarization vector in the third structure layer. .
　この構成により、本発明の一実施形態に係る情報処理デバイスは、誘電体により第３構造層を構成することで、第１領域にてスピン波を励起させることができるので、情報処理デバイスの構造を簡略化することができるとともに、ビアホール内に誘電体を埋め込む構成とすれば、電気信号とスピン波相互間の変換効率を向上させることができる。 With this configuration, the information processing device according to the embodiment of the present invention can excite spin waves in the first region by configuring the third structure layer with a dielectric, and thus the structure of the information processing device If the dielectric is embedded in the via hole, the conversion efficiency between the electric signal and the spin wave can be improved.
　（７）また、本発明の一実施形態に係る情報処理デバイスは、
　前記ビアホール内に埋め込まれた材料が、
　　前記入力信号の入力に伴い、スピン偏極電子流を生じ、
　前記第２構造層が、
　　前記ビアホール内の材料に生じたスピン偏極電子流に伴って生じる電気磁気効果に起因して磁気異方性が変化することにより前記第１領域にて前記スピン波が励起される、構成を有している。 (7) Further, an information processing device according to an embodiment of the present invention includes:
The material embedded in the via hole is
As the input signal is input, a spin-polarized electron current is generated,
The second structural layer comprises:
The spin wave is excited in the first region due to a change in magnetic anisotropy due to an electromagnetic effect caused by a spin-polarized electron flow generated in the material in the via hole. doing.
　この構成により、本発明の一実施形態に係る情報処理デバイスは、ビアホール内に重金属を埋め込む簡単な構成で、電気信号とスピン波を変換する際のエネルギー効率を向上させることができるとともに、電流信号を入力信号に用いることができる。 With this configuration, the information processing device according to an embodiment of the present invention can improve the energy efficiency when converting an electrical signal and a spin wave with a simple configuration in which heavy metal is embedded in a via hole, and a current signal. Can be used for the input signal.
　（８）また、本発明の一実施形態に係る情報処理デバイスは、前記ビアホール内に埋め込まれた材料が、
　　前記入力信号の入力に伴い、トンネル磁気抵抗効果により、スピンの歳差運動を生じ、
　前記第３構造が、
　　当該スピンからの漏えい磁場、或いは、当該スピンによるスピン間交換相互作用により磁気異方性が変化することによって、前記第１領域にて前記スピン波が励起される、構成を有している。 (8) In the information processing device according to an embodiment of the present invention, the material embedded in the via hole is
Along with the input of the input signal, due to the tunnel magnetoresistance effect, spin precession occurs,
The third structure is
The spin wave is excited in the first region by changing the magnetic anisotropy due to a leakage magnetic field from the spin or an inter-spin exchange interaction by the spin.
　この構成により、本発明の一実施形態に係る情報処理デバイスは、ビアホール内に磁気トンネル接合素子を設けることにより、電気信号とスピン波を変換する際のエネルギー効率を向上させることができるとともに、信号の入出力に電流信号を用いることができる。 With this configuration, the information processing device according to an embodiment of the present invention can improve the energy efficiency when converting an electric signal and a spin wave by providing a magnetic tunnel junction element in the via hole. A current signal can be used for the input / output.
　（９）また、本発明の一実施形態に係る情報処理デバイスは、
　前記第２電極に対して、直流バイアス電流を印加する電流印加手段を更に備える、構成を有している。 (9) An information processing device according to an embodiment of the present invention includes:
The device further includes a current applying unit that applies a DC bias current to the second electrode.
この構成により、本発明の一実施形態に係る情報処理デバイスは、直流バイアス電流を印加することによって、出力領域におけるスピンの動きを正確に検出することができる。 With this configuration, the information processing device according to the embodiment of the present invention can accurately detect the spin movement in the output region by applying the DC bias current.
［１］情報処理デバイス
　まず、図１を用いてスピン波を用いてリザバーを用いたコンピューティング（以下、「リザバーコンピューティング」という。）を実現するための情報処理デバイス１について説明する。なお、図１は、本実施形態の情報処理デバイス１の一構成例を示す図である。 [1] Information Processing Device First, an information processing device 1 for realizing computing using a reservoir using a spin wave (hereinafter referred to as “reservor computing”) will be described with reference to FIG. FIG. 1 is a diagram illustrating a configuration example of the information processing device 1 according to the present embodiment.
　本実施形態の情報処理デバイス１は、複数の信号が同時に入力された場合に、直前のスピン分布状態や各信号の相互作用を通して新たなスピン波を形成して（励起及び伝播）、これを複数の箇所にて検出を行い、同時に複数の信号を出力することにより、多入力・多出力型の入出力形態を実現し、リザバーとして機能するものである。 When a plurality of signals are input simultaneously, the information processing device 1 of the present embodiment forms a new spin wave (excitation and propagation) through the previous spin distribution state and the interaction of each signal, By detecting at this point and outputting a plurality of signals at the same time, a multi-input / multi-output type input / output configuration is realized and functions as a reservoir.
　具体的には、本実施形態の情報処理デバイス１は、図１に示すように、グランドに接続された導電性基板１１の上に積層されたガーネット薄膜１２と、このガーネット薄膜１２上に積層された磁電カップリング層１３を有し、物質波としてスピン波を用いて、多入力・多出力型のリザバーを実現するためのデバイスである。 Specifically, as shown in FIG. 1, the information processing device 1 of the present embodiment is stacked on a garnet thin film 12 stacked on a conductive substrate 11 connected to a ground, and on the garnet thin film 12. This device has a magnetoelectric coupling layer 13 and realizes a multi-input / multi-output type reservoir using a spin wave as a material wave.
　従来のロジック回路においては、信号を同時に多数入力することができないので、ニューロン型の入出力形態（すなわち、多入力・多出力）を実現しようとすると、入力信号を１つずつメモリに書き込み、全信号の書き込み後にメモリを同時に読み出す（重み付け総和をとる）という出力工程を経る必要がある。 In a conventional logic circuit, a large number of signals cannot be input simultaneously. Therefore, when trying to realize a neuron-type input / output configuration (that is, multiple inputs / multiple outputs), input signals are written to a memory one by one. It is necessary to go through an output process of simultaneously reading out the memory (taking the weighted sum) after writing the signal.
　このため、ロジック回路を用いた従来型のニューラルネットワークは、刻一刻と変化するデータを扱うために、膨大な量のメモリが必要となり、回路規模の縮小が困難である。また、物理的な配線も行わければならず、配線爆発の問題が生じるとともに、回路規模が増大し、消費電力も増大してしまう。 For this reason, a conventional neural network using a logic circuit requires a huge amount of memory to handle data that changes every moment, and it is difficult to reduce the circuit scale. Moreover, physical wiring must be performed, which causes a problem of wiring explosion, increases the circuit scale, and increases power consumption.
　一方、リザバーを実現する方法としては、レーザを用いたものがあるが、極小化や低消費電力化の観点から実現されていない。 On the other hand, as a method of realizing the reservoir, there is a method using a laser, but it has not been realized from the viewpoint of minimization and low power consumption.
　そこで、本実施形態の情報処理デバイスは、スピン波の伝搬という物理現象によって多入力及び他出力のデバイスとして構成し、入力に対して発生する物理現象に基づいて出力を決定するリザバーとしての機能を実現するとともに、規模の増大を防止しつつ、低消費電力化を実現している。 Therefore, the information processing device of this embodiment is configured as a multi-input and other-output device based on the physical phenomenon of spin wave propagation, and has a function as a reservoir that determines the output based on the physical phenomenon that occurs with respect to the input. In addition to realizing this, low power consumption is realized while preventing an increase in scale.
　ガーネット薄膜１２は、例えば、Ｔｍ３Ｆｅ５Ｏ１２及びＹ３Ｆｅ５Ｏ１２等のフェリ磁性体又は強磁性体により構成され、後述する入力領域において磁電カップリング層１３により励起されたスピン波を、伝搬させる伝達媒体として機能する。 The garnet thin film 12 is made of, for example, a ferrimagnetic material or a ferromagnetic material such as Tm 3 Fe 5 O 12 and Y 3 Fe 5 O 12 , and spin waves excited by the magnetoelectric coupling layer 13 in an input region to be described later. , Function as a transmission medium for propagation.
　磁電カップリング層１３は、例えば、圧電体や強誘電体により構成され、ガーネット薄膜１２に接する界面１３１と反対側の面１３２が各種信号の入出力面（以下、この面を「入出力面１３２」という。）となっている。 The magnetoelectric coupling layer 13 is made of, for example, a piezoelectric material or a ferroelectric material. A surface 132 opposite to the interface 131 in contact with the garnet thin film 12 is an input / output surface for various signals (hereinafter, this surface is referred to as “input / output surface 132”). ").
　そして、磁電カップリング層１３は、入出力面１３２に複数の入力用電極１４と複数の出力用電極１５が形成可能な構造を有している。 The magnetoelectric coupling layer 13 has a structure in which a plurality of input electrodes 14 and a plurality of output electrodes 15 can be formed on the input / output surface 132.
　入力用電極１４及び出力用電極１５は、その大きさ、数及び配置方法を自由に決めて入出力面１３２上の任意の領域に配設できる。すなわち、本実施形態の情報処理デバイス１は、物理的な制限を除き、入出力面１３２の面内であれば、好きな位置に好きな大きさの電極を好きな数だけ設置することができる。 The input electrode 14 and the output electrode 15 can be arranged in arbitrary regions on the input / output surface 132 by freely determining the size, number, and arrangement method. In other words, the information processing device 1 according to the present embodiment can install a desired number of electrodes having a desired size at a desired position as long as it is within the plane of the input / output surface 132 except for physical limitations. .
　特に、本実施形態の情報処理デバイス１を実際に利用する場合には、入出力のバリエーションを最も多く取れる配置を探し、目的のコンピューティング内容に合致するように入力用電極１４及び出力用電極１５の位置、大きさ及び数を最適化しつつ、電極を配置することが望ましい。 In particular, when the information processing device 1 according to the present embodiment is actually used, an input electrode 14 and an output electrode 15 are searched so as to find an arrangement capable of obtaining the largest input / output variation and match the target computing content. It is desirable to arrange the electrodes while optimizing the position, size and number of the electrodes.
　例えば、情報処理デバイス１により、１００入力・１００出力の入出力形態を実現する場合には、入出力面１３２に２００個以上の電極を設け、目的のコンピューティング内容に応じて、その中から、入出力のバリエーションを最も多く取れる配置を探しつつ、１００個の電極を入力用電極１４に選択するとともに、１００個の電極を出力用電極１５として選択して使用するようにすればよい。 For example, when the input / output configuration of 100 inputs / 100 outputs is realized by the information processing device 1, 200 or more electrodes are provided on the input / output surface 132, and depending on the target computing content, 100 electrodes may be selected as the input electrode 14 and 100 electrodes may be selected and used as the output electrode 15 while searching for an arrangement capable of obtaining the largest number of input / output variations.
　また、この場合には、目的のコンピューティング内容に応じて各電極の位置及び大きさを、適切に設定することが望ましい。 In this case, it is desirable to appropriately set the position and size of each electrode according to the target computing content.
　さらには、入出力面１３２内に多数の電極を予め配置し、その中から、目的のコンピューティングに応じて、所定の電極を入力用電極１４及び出力用電極１５として用いるようにしてもよい。 Furthermore, a large number of electrodes may be arranged in the input / output surface 132 in advance, and predetermined electrodes may be used as the input electrode 14 and the output electrode 15 in accordance with the target computing.
　この場合には、例えば、必要な出力数よりも多くの電極を出力用電極１５に割り当て、当該電極からの出力信号を外部回路にて利用しつつ、学習を行った結果、誤差が所定値を下回る電極の組み合わせを出力用電極１５として選択し、他の電極に関しては利用しないようにすることもできる。すなわち、当初設定した出力用電極１５から実際に出力用電極１５として用いる電極を取捨選択するようにしてもよい。 In this case, for example, more electrodes than the required number of outputs are assigned to the output electrode 15 and learning is performed while using an output signal from the electrodes in an external circuit, so that the error has a predetermined value. It is also possible to select a combination of lower electrodes as the output electrode 15 and not use it for the other electrodes. That is, the electrode actually used as the output electrode 15 may be selected from the initially set output electrode 15.
　一方、入力用電極１４及び出力用電極１５の材質については、任意であり、例えば、銅（Ｃｕ）や銀（Ａｇ）、金（Ａｕ）等の各種金属により構成することができる。 On the other hand, the material of the input electrode 14 and the output electrode 15 is arbitrary, and can be made of various metals such as copper (Cu), silver (Ag), and gold (Au).
　そして、各入力用電極１４及び出力用電極１５には、図示せぬ外部回路が電気的に接続されており、この外部回路から入力用電極１４に対して電気信号が供給される。 An external circuit (not shown) is electrically connected to each input electrode 14 and output electrode 15, and an electric signal is supplied from the external circuit to the input electrode 14.
　なお、図１には、入出力面１３２上に所定の大きさの入力用電極１４及び出力用電極１５をランダムに所定数配置した場合の電極配置例を示している。また、例えば、本実施形態の入力用電極１４及び出力用電極１５は、それぞれ、本発明の「第１電極」及び「第２電極」を構成する。 FIG. 1 shows an electrode arrangement example in which a predetermined number of input electrodes 14 and output electrodes 15 having a predetermined size are randomly arranged on the input / output surface 132. Further, for example, the input electrode 14 and the output electrode 15 of the present embodiment constitute the “first electrode” and the “second electrode” of the present invention, respectively.
　磁電カップリング層１３は、外部回路から入力用電極１４に対して電気信号が入力されると、ガーネット薄膜１２において入力用電極１４の設置領域に対応する領域（「入力領域」という。）の性質を局所的に変化させ、当該入力領域内にスピン波を励起させる機能を有している。 When an electric signal is input to the input electrode 14 from an external circuit, the magnetoelectric coupling layer 13 has a property of an area (referred to as an “input area”) corresponding to the installation area of the input electrode 14 in the garnet thin film 12. Has a function to excite spin waves in the input region.
　特に、入力領域において励起されたスピン波は、ガーネット薄膜１２において出力用電極１５の設置領域（以下、「出力領域」という。）までガーネット薄膜１２内を伝搬し、出力領域にて、再度電気信号に変換されて、出力用電極１５から出力される。すなわち、入力信号に対応する出力信号が、外部回路（各種の処理を実行する回路）に供給されることとなる。 In particular, the spin wave excited in the input region propagates in the garnet thin film 12 to the installation region of the output electrode 15 in the garnet thin film 12 (hereinafter referred to as “output region”), and in the output region again the electric signal And output from the output electrode 15. That is, an output signal corresponding to the input signal is supplied to an external circuit (a circuit that executes various processes).
　また、この構成により、本実施形態の情報処理デバイス１は規模を増大させることなく、多入力・多出力の入出力形態を実現し、リザバーコンピューティングを行う際の低消費電力化を実現することができる。 Also, with this configuration, the information processing device 1 according to the present embodiment realizes a multi-input / multi-output input / output configuration without increasing the scale, and realizes low power consumption when performing reservoir computing. Can do.
　なお、例えば、本実施形態の入力領域及び出力領域は、それぞれ、本発明の「第１領域」及び「第２領域」に相当する。また、本実施形態の情報処理デバイス１に印加される外部磁界については後述する。 Note that, for example, the input area and the output area of the present embodiment correspond to the “first area” and the “second area” of the present invention, respectively. The external magnetic field applied to the information processing device 1 of this embodiment will be described later.
［２］ガーネット薄膜におけるスピン波の励起原理
　次に、図２Ａ及び図２Ｂを用いてガーネット薄膜１２においてスピン波が励起される原理について説明する。 [2] Principle of Spin Wave Excitation in Garnet Thin Film Next, the principle of spin wave excitation in the garnet thin film 12 will be described with reference to FIGS. 2A and 2B.
　なお、図２Ａ及び図２Ｂは、本実施形態の情報処理デバイス１において入力用電極１４及び出力用電極１５の設置領域における情報処理デバイス１の断面構造を示す図である。特に、図２Ａは、方法１を実現する場合における断面構造を示す図、及び、図２Ｂは、方法２を実現する場合における断面構造を示す図である。 2A and 2B are diagrams illustrating a cross-sectional structure of the information processing device 1 in an installation region of the input electrode 14 and the output electrode 15 in the information processing device 1 of the present embodiment. In particular, FIG. 2A is a diagram showing a cross-sectional structure when the method 1 is realized, and FIG. 2B is a diagram showing a cross-sectional structure when the method 2 is realized.
　本実施形態の情報処理デバイス１においては、マイクロストリップアンテナを用いることなく、入力領域において局所的なスピン波を励起させる方法を採用している。 In the information processing device 1 of the present embodiment, a method of exciting a local spin wave in the input region without using a microstrip antenna is employed.
　具体的には、本実施形態の情報処理デバイス１においては、
（１）磁電カップリング層１３を構成する物質と、ガーネット薄膜１２を構成する物質の電子軌道の相互作用に起因するＭＥ効果（電気磁気効果）を用いて、入力領域にスピン波を励起する方法、または、
（２）フェリ磁性体としてのガーネット薄膜１２の入力領域に結晶の局所的歪みを与えることにより入力領域の一軸磁気異方性を変化させて、スピン波を励起する方法
を採用している。なお、ＭＥ効果とは、スピンの方向が変化すると分極が変化し、電場が変化するとスピンの方向が変化する現象をいうが、ＭＥ効果自体は周知であるため詳細を省略する。 Specifically, in the information processing device 1 of the present embodiment,
(1) A method of exciting a spin wave in an input region using the ME effect (electromagnetic effect) resulting from the interaction between the material constituting the magnetoelectric coupling layer 13 and the electron orbit of the material constituting the garnet thin film 12 Or
(2) A method is adopted in which spin waves are excited by changing the uniaxial magnetic anisotropy of the input region by applying local distortion of the crystal to the input region of the garnet thin film 12 as a ferrimagnetic material. The ME effect is a phenomenon in which the polarization changes when the spin direction changes, and the spin direction changes when the electric field changes. However, since the ME effect itself is well known, the details are omitted.
　上記の（１）の方法を採用する場合には、例えば、図２Ａに示すようにガーネット薄膜１２上に強誘電体により構成される磁電カップリング層１３を積層し、磁電カップリング層１３の入出力面１３２上に入力用電極１４及び出力用電極１５を設ける。そして、入力用電極１４に対して、電気信号（入力信号）としての電圧信号が入力される。 When the above method (1) is adopted, for example, as shown in FIG. 2A, a magnetoelectric coupling layer 13 made of a ferroelectric is laminated on the garnet thin film 12, and the magnetoelectric coupling layer 13 is inserted. The input electrode 14 and the output electrode 15 are provided on the output surface 132. A voltage signal as an electrical signal (input signal) is input to the input electrode 14.
　この構成により、入力用電極１４に電圧信号が入力された時点で、界面１３１の入力用電極１４直下の領域において磁電カップリング層１３の電子軌道と、ガーネット薄膜１２の電子軌道の相互作用が生じ、ＭＥ効果によりガーネット薄膜１２のスピンが変化して、入力領域にてスピン波が励起される。 With this configuration, when a voltage signal is input to the input electrode 14, an interaction between the electron orbit of the magnetoelectric coupling layer 13 and the electron orbit of the garnet thin film 12 occurs in a region immediately below the input electrode 14 of the interface 131. The spin of the garnet thin film 12 is changed by the ME effect, and the spin wave is excited in the input region.
　また、このようにして励起されたスピン波は、ガーネット薄膜１２内を出力領域まで伝搬し、出力領域にて磁電カップリング層１３の電子軌道と、ガーネット薄膜１２の電子軌道の相互作用が生じ、当該スピン波が電圧信号に変換されて、出力用電極１５から当該電圧信号が出力信号として出力される。 Further, the spin wave excited in this way propagates in the garnet thin film 12 to the output region, and an interaction between the electron orbit of the magnetoelectric coupling layer 13 and the electron orbit of the garnet thin film 12 occurs in the output region, The spin wave is converted into a voltage signal, and the voltage signal is output from the output electrode 15 as an output signal.
　一方、上記の方法２を採用する場合には、例えば、図２Ｂに示すようにガーネット薄膜１２上に圧電体により構成される磁電カップリング層１３を積層し、磁電カップリング層１３の入出力面１３２上に入力用電極１４及び出力用電極１５を設ける。そして、入力用電極１４に対して、電気信号（入力信号）としての電圧信号が入力される。 On the other hand, when the above method 2 is adopted, for example, as shown in FIG. 2B, a magnetoelectric coupling layer 13 made of a piezoelectric material is laminated on the garnet thin film 12, and the input / output surface of the magnetoelectric coupling layer 13 is stacked. An input electrode 14 and an output electrode 15 are provided on 132. A voltage signal as an electrical signal (input signal) is input to the input electrode 14.
　この構成により、入力用電極１４に電圧信号が入力された時点で、入力用電極１４と導電性基板１１の間に電界が発生し、磁電カップリング層１３において入力用電極１４の配設された領域が収縮する。 With this configuration, when a voltage signal is input to the input electrode 14, an electric field is generated between the input electrode 14 and the conductive substrate 11, and the input electrode 14 is disposed in the magnetoelectric coupling layer 13. The area shrinks.
　したがって、ガーネット薄膜１２の入力領域においては、結晶構造に歪みが生じ、結晶の磁気異方性が変化してスピン波が励起され、出力領域まで伝搬する。 Therefore, in the input region of the garnet thin film 12, the crystal structure is distorted, the magnetic anisotropy of the crystal is changed, and the spin wave is excited and propagates to the output region.
　そして、伝搬したスピン波により、ガーネット薄膜１２と磁電カップリング層１３の相互作用が生じ、出力領域にてスピン波が再度電圧信号に変換され、出力用電極１５から当該電圧信号が出力信号として出力される。 The propagated spin wave causes an interaction between the garnet thin film 12 and the magnetoelectric coupling layer 13, and the spin wave is converted again into a voltage signal in the output region, and the voltage signal is output from the output electrode 15 as an output signal. Is done.
　また、材料が強誘電体としての性質と圧電体としての性質を併せ持つことがあるが、どちらの性質が作用した場合においても電圧信号により入力領域にてスピン波を励起させ、伝搬したスピン波を再度電圧信号に変換することが可能である。 In addition, the material may have both the properties of a ferroelectric and a piezoelectric, but in either case, the spin wave is excited in the input region by the voltage signal and the propagated spin wave is It can be converted again into a voltage signal.
　この結果、本実施形態の情報処理デバイス１は、大きなアンテナを搭載することなく、電圧信号とスピン波の相互変換が行えるので、規模が大きくなることを防止することができる。 As a result, the information processing device 1 according to the present embodiment can perform mutual conversion between the voltage signal and the spin wave without mounting a large antenna, and thus can prevent the scale from increasing.
　なお、磁電カップリング層１３の構造に関しては、図２Ａ及び図２Ｂに例示する構造には限定されない。例えば、入力用電極１４及び出力用電極１５の設置直下領域にビアホール１６を設ける構成としてもよいが、詳しくは変形例の項にて説明する。 It should be noted that the structure of the magnetoelectric coupling layer 13 is not limited to the structure illustrated in FIGS. 2A and 2B. For example, the via hole 16 may be provided in the region immediately below the input electrode 14 and the output electrode 15, but details will be described in the section of the modification.
　また、情報処理デバイス１に、より確実に、空間に対して非対称であり、かつ、非線形干渉を起こすスピン波を励起させるために、外部直流磁場を印加してもよい。 Further, an external DC magnetic field may be applied to the information processing device 1 in order to excite spin waves that are asymmetric with respect to space and cause nonlinear interference.
　ここで、現在までに提案されているスピン波を利用するデバイスは、スピン波の線形干渉を用いるものが多い。 Here, many devices using spin waves that have been proposed so far use linear interference of spin waves.
　すなわち、このような従来のデバイスでは、線形干渉を生じさせるために０．１～０．２Ｔ程度の比較的強い磁場を印加してスピン波を励起させることでスピン波の線形干渉を生じさせている。 That is, in such a conventional device, in order to cause linear interference, a relatively strong magnetic field of about 0.1 to 0.2 T is applied to excite the spin wave, thereby causing the linear interference of the spin wave. Yes.
　しかしながら、実際にリザバーに適用する場合には、出力の多様性が求められるため、磁電カップリング層１３により励起されるスピン波は、線形干渉を起こすものよりも非線形干渉を起こすものの方がより好ましい。 However, when actually applied to a reservoir, a variety of outputs is required, so that the spin wave excited by the magnetoelectric coupling layer 13 is more preferable to cause nonlinear interference than to cause linear interference. .
　ここで、ガーネット薄膜１２における各スピンは、＋ｚ軸方向に対して、０．１～０．２Ｔ（テスラ）程度の比較的強い外部直流磁場が印加されている状態では、直流磁場が有効磁場内で支配的になるので、スピンがｚ軸方向に揃い、円錐角の小さな安定した歳差運動を行い、磁電カップリング層１３により励起されるスピン波の綺麗な線形干渉が生じる。このとき、各スピンの傾きは、面内方向に対する成分で０．１～０．２％程度である。 Here, each spin in the garnet thin film 12 is in the effective magnetic field when a relatively strong external DC magnetic field of about 0.1 to 0.2 T (Tesla) is applied to the + z-axis direction. Therefore, the spins are aligned in the z-axis direction, perform stable precession with a small cone angle, and clean linear interference of the spin wave excited by the magnetoelectric coupling layer 13 occurs. At this time, the inclination of each spin is about 0.1 to 0.2% as a component with respect to the in-plane direction.
　一方、＋ｚ方向に印加される直流磁場が小さくなると、これに伴い、直流磁場方向への復元力が小さくなり、すべての領域、あるいは、ある程度の領域においてガーネット薄膜１２内のスピンの傾き（すなわち、図２Ａ及び図２Ｂの左右方向、又は、紙面垂直方向の傾き）が、大きくなる。 On the other hand, when the DC magnetic field applied in the + z direction is reduced, the restoring force in the DC magnetic field direction is reduced accordingly, and the spin gradient in the garnet thin film 12 in all regions or a certain region (ie, 2A and 2B or the inclination in the direction perpendicular to the paper surface) increases.
　このようにして、スピンの傾きが大きくなると、そのスピンが作るダイポール磁場が他のスピンに作用する有効磁場を＋ｚ方向から乖離させ、これにより、さらに周りのスピンの有効磁場が＋ｚから乖離し、有効磁場の分布が変動し続けることとなる。 In this way, when the spin gradient increases, the dipole magnetic field created by the spin deviates from the effective magnetic field acting on the other spins from the + z direction, so that the effective magnetic field of the surrounding spin further deviates from + z, The distribution of the effective magnetic field will continue to fluctuate.
　このため、各スピンは、常に有効磁場がぐらついた状態となる。すなわち、時々刻々と変化する有効磁場を中心に回転をしようとするもの、その際にまた有効磁場が変化する、という非常に不安定な回転運動を続けることとなる。 For this reason, each spin always has a wobbling effective magnetic field. In other words, a very unstable rotational motion in which an effective magnetic field that changes from moment to moment is attempted to rotate, and the effective magnetic field changes at that time is continued.
　この結果、一つのスピンの傾きが大きくなると、それが他のスピンの有効磁場を変化させ、それがまた自らのスピンの有効磁場を変化させる正のフィードバックが進行することになり、ガーネット薄膜１２において非対称かつ非線形干渉を生じるスピン波が励起されることとなる。 As a result, when the inclination of one spin increases, it changes the effective magnetic field of the other spin, and this also causes positive feedback that changes the effective magnetic field of its own spin. A spin wave that causes asymmetric and nonlinear interference is excited.
　そこで、本実施形態においては、図１に示すように、情報処理デバイス１に印加する直流磁場を、
（１）＋ｚ方向に０．０３Ｔ（テスラ）、
（２）＋ｙ方向に０．０００１Ｔ、
の比較的弱い値とし、非対称かつ非線形干渉を起こすスピン波を励起・伝播させる構成を採用することとした。 Therefore, in the present embodiment, as shown in FIG. 1, the DC magnetic field applied to the information processing device 1 is
(1) 0.03T (Tesla) in the + z direction,
(2) 0.0001T in the + y direction,
It was decided to adopt a configuration that excites and propagates spin waves that cause asymmetric and nonlinear interference.
　例えば、本実施形態の構成を採用する場合には、上記の形態で外部磁場を印加することにより、面内方向の成分で３～１０％程度のスピンが傾くので、非対称かつ非線形性の干渉を生じるスピン波を励起させることができる。 For example, when the configuration of the present embodiment is adopted, by applying an external magnetic field in the above-described form, a spin of about 3 to 10% is tilted in a component in the in-plane direction. The generated spin wave can be excited.
　そして、本実施形態の情報処理デバイス１は、図１に示すような外部直流磁場が印加されることによって、ガーネット薄膜１２において非対称かつ非線形の干渉を生じるスピン波を励起させることができるので、リザバーコンピューティングを行う際における出力の多様性を確保することができる。 The information processing device 1 of the present embodiment can excite spin waves that cause asymmetric and nonlinear interference in the garnet thin film 12 by applying an external DC magnetic field as shown in FIG. Diversity of output when computing is ensured.
　なお、図１に示す直流外部磁場の印加形態（方向及び大きさ）はあくまでも一例であり、ガーネット薄膜１２及び磁電カップリング層１３として利用する材質に応じて、情報処理デバイス１に印加する磁場を変更することが望ましい。 Note that the DC external magnetic field application mode (direction and magnitude) shown in FIG. 1 is merely an example, and the magnetic field applied to the information processing device 1 is determined according to the material used as the garnet thin film 12 and the magnetoelectric coupling layer 13. It is desirable to change.
　この場合には、磁場の強さをスピン波の非線形干渉が生じる程度に調整するようにすることが必要となる。例えば、ガーネット薄膜１２として用いる材料に応じて、後述する（式１）の磁化ベクトル（Ｍ）やダンピング定数（α）の大きさが変化するので、利用する材料に応じて、適切に直流磁場の大きさを調整することが望ましい。 In this case, it is necessary to adjust the strength of the magnetic field to such an extent that non-linear interference of spin waves occurs. For example, depending on the material used as the garnet thin film 12, the magnitude of the magnetization vector (M) and the damping constant (α) in (Equation 1) to be described later change. It is desirable to adjust the size.
　また、利用する材料によっては外部磁場をなくして初めて非線形干渉が起きるような物質も想定されるので、この種の材料を利用する場合には、外部磁場を印加しない構成とすることも可能である。 In addition, depending on the material used, a substance that causes non-linear interference only when the external magnetic field is eliminated is assumed. Therefore, when this type of material is used, a configuration in which an external magnetic field is not applied is also possible. .
　さらに、上記のように＋ｙ方向に弱い磁場を印加することにより、励起されるスピン波の特性（非対称性と非線形干渉性）を向上させ、リザバーとしての性能を向上させることができるが、＋ｙ方向に磁場を印加すること自体は本発明に必須の要件ではなく、非対称かつ非線形干渉を生じるスピン波を励起させることができれば、＋ｙ方向に外部磁場を印加することは必ずしも必要とならない。 Furthermore, by applying a weak magnetic field in the + y direction as described above, it is possible to improve the characteristics (asymmetry and non-linear interference) of the excited spin wave and improve the performance as a reservoir. The application of a magnetic field to itself is not an essential requirement of the present invention, and it is not always necessary to apply an external magnetic field in the + y direction if a spin wave that causes asymmetric and nonlinear interference can be excited.
　また、本実施形態の情報処理デバイス１は、従来の磁気バブル技術を用いることにより、当該情報処理デバイス１と一体化されたモジュールによって外部直流磁場を印加する構成を有している。ただし、外部直流磁場を印加する構造についてはこの限りでない。 Further, the information processing device 1 of the present embodiment has a configuration in which an external DC magnetic field is applied by a module integrated with the information processing device 1 by using a conventional magnetic bubble technology. However, this does not apply to a structure that applies an external DC magnetic field.
　さらに、本実施形態においては、＋ｚ方向及び＋ｙ方向の両方向に対して、個別に外部直流磁場を印加する構成とすることもできるが、＋ｚ方向に対して、０．０３Ｔの外部直流磁場を印加する際に、外部直流磁場の印加方向を＋ｙ方向に１°チルトさせる（傾ける）ことによっても、上記の態様にて情報処理デバイス１に外部直流磁場を印加することができる。 Furthermore, in the present embodiment, an external DC magnetic field can be individually applied to both the + z direction and the + y direction, but an 0.03 T external DC magnetic field is applied to the + z direction. When the external DC magnetic field is applied, the external DC magnetic field can be applied to the information processing device 1 in the above-described manner by tilting (tilting) the application direction of the external DC magnetic field by 1 ° in the + y direction.
［３］リザバーを利用したコンピューティングのシミュレーション結果
　次に、上記構成を有する情報処理デバイス１により、リザバーコンピューティングの実現可能性についてシミュレーションした結果について説明する。 [3] Simulation Result of Computing Using Reserver Next, a result of simulating the feasibility of reservoir computing by the information processing device 1 having the above configuration will be described.
［３．１］シミュレーション条件
［３．１．１］シミュレーションに用いた情報処理デバイス
　まず、図３Ａ及び図３Ｂを用いて本実施形態におけるシミュレーションに用いた情報処理デバイス１について説明する。 [3.1] Simulation Conditions [3.1.1] Information Processing Device Used for Simulation First, the information processing device 1 used for the simulation in the present embodiment will be described with reference to FIGS. 3A and 3B.
　なお、図３Ａ及び図３Ｂは、本実施形態におけるシミュレーション条件を説明するための図である。特に、図３Ａ及び図３Ｂは、シミュレーション用の情報処理デバイス１におけるガーネット薄膜１２の構成、情報処理デバイス１に印加する外部磁場の方向及び強度の関係、及び、本シミュレーションにおけるスピン波の励起位置及び検出位置の配置を説明するための図である。また、図３ＢにおいてＥｘｃｉｔｅｒ１及び２は、スピン波の励起位置、Ｄｅｔｅｃｔｏｒ１、２及び３は、スピン波の検出位置を示している。 3A and 3B are diagrams for explaining simulation conditions in the present embodiment. In particular, FIGS. 3A and 3B show the configuration of the garnet thin film 12 in the information processing device 1 for simulation, the relationship between the direction and intensity of the external magnetic field applied to the information processing device 1, and the excitation position of the spin wave in this simulation. It is a figure for demonstrating arrangement | positioning of a detection position. In FIG. 3B, Exciters 1 and 2 indicate spin wave excitation positions, and Detectors 1, 2, and 3 indicate spin wave detection positions.
　本シミュレーションにおいては、図３Ａに示すように、２０μｍ×２０μｍ×１００ｎｍの平面構造のガーネット薄膜１２を用いて構成される情報処理デバイス１を用いた。 In this simulation, as shown in FIG. 3A, an information processing device 1 configured using a garnet thin film 12 having a planar structure of 20 μm × 20 μm × 100 nm was used.
　なお、図示はしていないが、図３Ａに示すガーネット薄膜１２の下には導電性基板１１が形成され、グランドに接続されているとともに、ガーネット薄膜１２上には磁電カップリング層１３が積層されている。 Although not shown, a conductive substrate 11 is formed under the garnet thin film 12 shown in FIG. 3A and connected to the ground, and a magnetoelectric coupling layer 13 is laminated on the garnet thin film 12. ing.
　また、この情報処理デバイス１においては、
（１）図３Ａにおいて薄いグレーで示される内側の１９μｍ×１９μｍ×１００ｎｍの伝搬領域と、
（２）外側の濃いグレーの減衰領域と、
にガーネット薄膜１２を分け、内側の伝搬領域のダンピング定数を０．００１、外側の減衰領域のダンピング定数を１とした。 In this information processing device 1,
(1) Inner 19 μm × 19 μm × 100 nm propagation region shown in light gray in FIG. 3A;
(2) an outer dark gray attenuation region;
The garnet thin film 12 is divided into a damping constant of 0.001 for the inner propagation region and a damping constant of 1 for the outer attenuation region.
　特に、ダイナミクスは、下記の（式１）のＬＬＧ（Ｌａｎｄａｕ－Ｌｉｆｓｈｉｔｚ－Ｇｉｌｂｅｒｔ）方程式により表される。ただし、（式１）において、Ｍは、磁化ベクトル、Ｈｅｆｆは、有効磁場、γはジャイロ磁気定数、αは、ダンピング定数、Ｍｓは、飽和磁化（磁化ベクトルの大きさ、スカラー量）である。なお、ここでいう「磁化」とは、「スピン」と同義に解釈して差し支えない。 In particular, the dynamics is represented by the following LLG (Landau-Lifshitz-Gilbert) equation (Equation 1). However, in (Equation 1), M is a magnetization vector, H eff is an effective magnetic field, γ is a gyro magnetic constant, α is a damping constant, and M s is saturation magnetization (magnetization vector magnitude, scalar quantity). is there. The term “magnetization” here can be interpreted synonymously with “spin”.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　なお、（式１）の右辺第一項がスピンの歳差運動を示し、第二項がＨｅｆｆに向かう制動項、すなわち歳差運動の減衰項を示している。また、（式１）において、γの次元は、ｒａｄ／ｓＴ（ラジアン／（秒×テスラ））である。 Note that the first term on the right side of (Equation 1) indicates the precession of the spin, and the second term indicates the braking term toward H eff , that is, the decay term of the precession. In (Expression 1), the dimension of γ is rad / sT (radians / (seconds × tesla)).
　この構成により入力領域（Ｅｘｃｉｔｅｒ１及び２）にて励起されたスピン波が、内側の領域を著しく減衰することなく伝搬するとともに、外側の領域まで伝搬した時点で速やかに減衰することとなる。 With this configuration, the spin wave excited in the input region (Exciters 1 and 2) propagates in the inner region without being significantly attenuated and quickly attenuates when it propagates to the outer region.
　この結果、ガーネット薄膜１２の端部において、スピン波が反射して、シミュレーション結果に誤差が生じることを防止することができる。 As a result, it is possible to prevent the spin wave from being reflected at the end of the garnet thin film 12 and causing an error in the simulation result.
　なお、情報処理デバイス１においては、端面反射が生じてもリザバーとしての機能に大きな問題が生じないので、図３Ａのように、ガーネット薄膜１２にダンピング定数の異なる２つの領域を設けることは必須とならないが、本シミュレーションにおいては、反射波の影響を除去するため、図３Ａのような構成のガーネット薄膜１２を有する情報処理デバイス１を用いている。 In the information processing device 1, even if end face reflection occurs, no major problem occurs in the function as a reservoir. Therefore, as shown in FIG. 3A, it is essential to provide two regions with different damping constants in the garnet thin film 12. However, in this simulation, in order to remove the influence of the reflected wave, the information processing device 1 having the garnet thin film 12 having the configuration as shown in FIG. 3A is used.
　なお、この情報処理デバイス１においては、以下の設定をしてシミュレーションを行った。
（１）ガーネット薄膜１２の飽和磁化ＭＳを、１００ｋＡ／ｍに設定
（２）交換剛性定数ＡＥＸを、３．７×１０－１２Ｊ／ｍに設定
（３）ガーネット薄膜１２の全領域を直交座標系に沿って１０ｎｍ×１０ｎｍ×５０ｎｍの体積を有するスモールメッシュに分割
（４）シミュレーション温度を０Ｋに設定
（５）ほぼすべてのスピン方向を＋ｚ方向に沿わせる（具体的には、９９．９９％）初期化操作を行った後、情報処理デバイス１に印加する外部直流磁場を、図３Ｂに示すように＋ｚ方向に０．０３Ｔ、＋ｙ方向に０．０００１Ｔまで緩和させる操作を実行 In the information processing device 1, simulation was performed with the following settings.
(1) the saturation magnetization M S of garnet films 12, the entire area of 100 kA / m set to (2) exchange stiffness constant A EX, set to 3.7 × 10 -12 J / m ( 3) garnet films 12 Divide into small meshes having a volume of 10 nm × 10 nm × 50 nm along the Cartesian coordinate system (4) Set simulation temperature to 0K (5) Set almost all spin directions along + z direction (specifically, 99. 99%) After the initialization operation, the external DC magnetic field applied to the information processing device 1 is relaxed to 0.03T in the + z direction and 0.0001T in the + y direction as shown in FIG. 3B.
　なお、初期化操作において、スピンの方向を＋ｚ方向に沿わせたのは、本シミュレーションにおいて、例えばこの直流磁場をいきなり印加すると、これにより全体のスピン分布が変わってしまいシミュレーション結果に影響を与える可能性がある可能性があるので、これを防止するためである。具体的には、直流磁場により、Ｅｘｃｉｔｅｒ以外の領域のスピンが変化すると、観測された現象が直流磁場の印加に起因した現象であるのか、スピン波の励起・伝播に起因した現象であるのか判別できなくなる可能性があるため、このような事態を防止するため、直流磁場によってスピンが動くことを初期化操作により防止した。 In the initialization operation, the spin direction is set in the + z direction. In this simulation, for example, if this DC magnetic field is applied suddenly, the overall spin distribution changes, which may affect the simulation result. This is to prevent this. Specifically, when the spin in a region other than the exciter is changed by a DC magnetic field, it is determined whether the observed phenomenon is a phenomenon caused by the application of a DC magnetic field or a phenomenon caused by the excitation / propagation of a spin wave. In order to prevent such a situation, the spin operation was prevented by the initialization operation in order to prevent such a situation.
　なお、スピンは、スモールメッシュのコーナー部分に位置することとなる。 Note that the spin is located at the corner of the small mesh.
　また、図３Ａにおけるｘ軸とｙ軸の交点（０，０）は、図３Ｂにおけるｘ軸とｙ軸の交点（０，０）の座標と位置を合わせてある。 Further, the intersection (0, 0) of the x axis and the y axis in FIG. 3A is the same as the coordinate (0, 0) of the intersection (0, 0) of the x axis and the y axis in FIG. 3B.
　そして、図３ＢのＥｘｃｉｔｅｒ１及び２の位置に中心が合うように直径２５０ｎｍの入力用電極１４を設けるとともに、Ｄｅｔｅｃｔｏｒ１、２及び３の位置に中心が合うように直径１００ｎｍの出力用電極１５を設けた。 In addition, an input electrode 14 having a diameter of 250 nm is provided so that the center is aligned with the positions of Exciters 1 and 2 in FIG. 3B, and an output electrode 15 having a diameter of 100 nm is provided so that the centers are aligned with the positions of Detectors 1, 2, and 3. .
　具体的には、図３Ｂに示すように、（１μｍ，０）及び（－１μｍ，０）の位置に、それぞれ、Ｅｘｃｉｔｅｒ１及び２に対応する入力用電極１４を設けるとともに、（０，０）点の位置にＤｅｔｅｃｔｏｒ２、（０，１μｍ）の位置にＤｅｔｅｃｔｏｒ１、（０，－１μｍ）の位置にＤｅｔｅｃｔｏｒ３に対応する出力用電極１５を設けた。 Specifically, as shown in FIG. 3B, input electrodes 14 corresponding to Exciters 1 and 2 are provided at positions (1 μm, 0) and (−1 μm, 0), respectively, and (0, 0) points are provided. The output electrode 15 corresponding to the Detector 2 is provided at the position of Detector 2 at the position of Detector 2, at the position of (0, 1 μm), and at the position of (0, −1 μm).
　なお、Ｅｘｃｉｔｅｒ１及び２の位置に設けられる入力用電極１４の設置領域に対応するガーネット薄膜１２上の領域は、上記入力領域として機能し、Ｄｅｔｅｃｔｏｒ１，２，３の位置設けられる出力用電極１５の設置領域に対応するガーネット薄膜１２上の領域は、上記出力領域として機能する。 The area on the garnet thin film 12 corresponding to the installation area of the input electrode 14 provided at the positions of the Exciters 1 and 2 functions as the input area, and the installation of the output electrode 15 provided at the positions of the Detectors 1, 2, 3 is provided. A region on the garnet thin film 12 corresponding to the region functions as the output region.
　そして、図３Ａに示すように、外部直流磁場（すなわち、＋ｚ方向に０．０３Ｔ、＋ｙ方向に０．０００１Ｔ）を印加した状態で、入力用電極１４にスピン波励起用の電圧信号を入力し、入力領域におけるガーネット薄膜１２のｚ方向垂直一軸磁気異方性Ｋｕ（以下、「一軸磁気異方性Ｋｕ」という。）を変化させることにより、入力領域にてスピン波を励起させ、情報処理デバイス１におけるスピン波の特性を評価した。 As shown in FIG. 3A, a voltage signal for spin wave excitation is input to the input electrode 14 with an external DC magnetic field applied (ie, 0.03 T in the + z direction and 0.0001 T in the + y direction). By changing the z-direction perpendicular uniaxial magnetic anisotropy Ku (hereinafter referred to as “uniaxial magnetic anisotropy Ku”) of the garnet thin film 12 in the input region, a spin wave is excited in the input region, and the information processing device The characteristics of the spin wave at 1 were evaluated.
［４．１．２］シミュレーションに用いたスピン波励起用の信号
　次に、図４Ａ及び図４Ｂを用いて本シミュレーションに用いたスピン波励起用の信号について説明する。 [4.1.2] Spin Wave Excitation Signal Used for Simulation Next, the spin wave excitation signal used for the simulation will be described with reference to FIGS. 4A and 4B.
　なお、図４Ａ及び図４Ｂは、本シミュレーションにおいて用いたスピン波励起用の信号を説明するための図である。特に、図４Ａは、ガーネット薄膜１２において１回のみスピン波を励起させる場合に用いるスピン波励起用の信号を説明するための図であり、図４Ｂは、ガーネット薄膜１２において、２回、スピン波を励起させる場合に用いるスピン波励起用の信号を説明するための図である。 4A and 4B are diagrams for explaining the signals for spin wave excitation used in this simulation. In particular, FIG. 4A is a diagram for explaining a spin wave excitation signal used when a spin wave is excited only once in the garnet thin film 12, and FIG. 4B is a diagram illustrating a spin wave twice in the garnet thin film 12. It is a figure for demonstrating the signal for the spin wave excitation used when exciting.
　また、図４Ａ及び図４Ｂにおいては、時間軸（横軸）の開始位置を０点とするとともに、横軸に対して１ｎｓ（ナノ秒）毎に目盛を付している。 4A and 4B, the start position of the time axis (horizontal axis) is set to 0 point, and a scale is added to the horizontal axis every 1 ns (nanosecond).
（ガーネット薄膜において１回のみスピン波を励起させる場合）
　この場合には、Ｅｘｃｉｔｅｒの領域における一軸磁気異方性Ｋｕを、図４Ａのように変化させるための電圧信号（以下、「１回励起信号」という。）をＥｘｃｉｔｅｒの位置に設置された入力用電極１４に入力した。 (When a spin wave is excited only once in a garnet thin film)
In this case, a voltage signal for changing the uniaxial magnetic anisotropy Ku in the region of Exciter as shown in FIG. 4A (hereinafter referred to as “single excitation signal”) is used for input installed at the position of Exciter. Input to electrode 14.
　このとき、図４Ａにおいて一軸磁気異方性ＫｕをＫｕＬに維持する１ｓｔの区間の時間長が３ｎｓ（ナノ秒）、その後、一軸磁気異方性Ｋｕの値がＫｕＨに維持されるように１回励起信号の電圧値を制御した。 At this time, in FIG. 4A, the time length of the 1 st section for maintaining the uniaxial magnetic anisotropy Ku at Ku L is 3 ns (nanoseconds), and then the value of the uniaxial magnetic anisotropy Ku is maintained at Ku H. The voltage value of the excitation signal was controlled once.
（ガーネット薄膜においてスピン波を２回励起させる場合）
　この場合には、一軸磁気異方性Ｋｕを、図４Ｂに示すように２回ステップの形態にて変化させるための電圧信号（以下、「２回励起信号」という。）をＥｘｃｉｔｅｒの位置に設置された入力用電極１４に入力した。 (When spin waves are excited twice in a garnet thin film)
In this case, a voltage signal (hereinafter referred to as “twice excitation signal”) for changing the uniaxial magnetic anisotropy Ku in a two-step format as shown in FIG. 4B is installed at the position of Exciter. Input to the input electrode 14.
　このとき、
（１）Ｋｕ＝ＫｕＬとする１ｓｔの区間の時間長が３ｎｓ、
（２）Ｋｕ＝ＫｕＨとする２ｎｄの時間長がＸｎｓ（以下、このＸの値を「Ｘ値」という。）、
（３）Ｋｕ＝ＫｕＬとする３ｒｄの区間の時間長が３ｎｓ、及び、
（４）Ｋｕ＝ＫｕＨとする４ｔｈの区間の時間長が６ｎｓ、
となるように入力用電極１４に入力する２回励起信号の電圧値を制御した。 At this time,
(1) The time length of the 1 st section where Ku = Ku L is 3 ns,
(2) The time length of 2 nd with Ku = Ku H is Xns (hereinafter, the value of X is referred to as “X value”),
(3) the time length of 3 rd interval to Ku = Ku L is 3ns and,
(4) The time length of the 4 th section where Ku = Ku H is 6 ns,
The voltage value of the twice excitation signal input to the input electrode 14 was controlled so that
　なお、図４Ｂには、Ｘ値を「３ｎｓ」とした場合における一軸磁気異方性Ｋｕの変化状態を示している。 4B shows a change state of the uniaxial magnetic anisotropy Ku when the X value is “3 ns”.
　また、Ｅｘｃｉｔｅｒ領域に設置された入力用電極１４に入力する電圧信号の電圧値については、任意であるが、ガーネット薄膜１２及び磁電カップリング層１３として用いる材質に合わせて、ＫＵＬ＝１ｋＪ／ｍ３、ＫＵＨ＝１０ｋＪ／ｍ３となるように適切に電圧値を設定してある。 Further, the voltage value of the voltage signal input to the input electrode 14 installed in the Exciter region is arbitrary, but KU L = 1 kJ / m according to the material used for the garnet thin film 12 and the magnetoelectric coupling layer 13. 3 and KU H = 10 kJ / m 3 , voltage values are set appropriately.
　さらに、図４Ａ及び図４Ｂに示す一軸磁気異方性Ｋｕの変化は、入力領域における変化であって、Ｅｘｃｉｔｅｒに対応する領域以外の領域では一軸磁気異方性Ｋｕが、常時ＫｕＨに維持される。 Furthermore, the change in the uniaxial magnetic anisotropy Ku shown in FIGS. 4A and 4B is a change in the input region, and the uniaxial magnetic anisotropy Ku is always maintained at Ku H in a region other than the region corresponding to Exciter. The
［４．２］ガーネット薄膜において励起されるスピン波
　次に、上記条件にて、Ｅｘｃｉｔｅｒの位置に設置された入力用電極１４に電圧信号（すなわち、１回励起信号又は２回励起信号）を入力してスピン波を励起させ、Ｄｅｔｅｃｔｏｒ１，２，３の位置にてスピン波のｘｙｚ成分（以下、それぞれ、「ｓｘ成分」、「ｓｙ成分」、「ｓｚ成分」という。）を検出した結果について説明する。 [4.2] Spin wave excited in garnet thin film Next, a voltage signal (that is, a one-time excitation signal or a two-time excitation signal) is input to the input electrode 14 installed at the position of the Exciter under the above conditions. Then, the result of exciting the spin wave and detecting the xyz component of the spin wave (hereinafter referred to as “sx component”, “sy component”, and “sz component”, respectively) at the positions of Detectors 1, 2, and 3 will be described. To do.
［４．２．１］スピン波のシミュレーション結果１
　まず、図５を用いてＥｘｃｉｔｅｒ１に対応する入力用電極１４に１回励起信号を入力した際に励起されるスピン波のシミュレーション結果について説明する。 [4.2.1] Spin wave simulation result 1
First, the simulation result of the spin wave excited when the excitation signal is input once to the input electrode 14 corresponding to Excitter 1 will be described with reference to FIG.
　なお、図５は、本実施形態のシミュレーションにおいて、Ｅｘｃｉｔｅｒ１に設けられた入力用電極に１回励起信号を入力した場合に、Ｄｅｔｅｃｔｏｒ１，２，３の領域にて検出されたスピン波の空間分布を示す図である。特に、図５は、ｓｘ成分の空間分布を示す図とり、ｓｙ成分の空間分布を示す図とである。 FIG. 5 shows the spatial distribution of spin waves detected in the areas of Detectors 1, 2, and 3 when an excitation signal is input once to the input electrode provided in Exciter 1 in the simulation of this embodiment. FIG. In particular, FIG. 5 is a diagram showing the spatial distribution of the sx component and a diagram showing the spatial distribution of the sy component.
　最初に、情報処理デバイス１において励起されるスピン波の基本的性質を調べるため、Ｅｘｃｉｔｅｒ１の位置に設置した入力用電極１４に対してのみ１回励起信号を入力し、Ｅｘｃｉｔｅｒ１の領域にてスピン波を１回のみ励起させるとともに、Ｄｅｔｅｃｔｏｒ１，２，３に対応する出力領域にてスピン波を検出した。 First, in order to investigate the basic property of the spin wave excited in the information processing device 1, an excitation signal is input only to the input electrode 14 installed at the position of the Exciter 1, and the spin wave is generated in the Exciter1 region. Was excited only once, and a spin wave was detected in the output region corresponding to Detectors 1, 2, and 3.
　このとき、図５における０点からの経過時間数ｔが「７ｎｓ」になったタイミングで、Ｄｅｔｅｃｔｏｒ１，２，３の領域にて検出されたスピン波の空間分布を図５に示す。 At this time, the spatial distribution of the spin waves detected in the areas of Detectors 1, 2, and 3 at the timing when the elapsed time t from point 0 in FIG. 5 becomes “7 ns” is shown in FIG.
　また、図５においては、上下方向及び左右方向のサイズをそれぞれ１０μｍとし、１０μｍ×１０μｍの領域における空間分布を示すとともに、ｘ軸及びｙ軸のそれぞれに対して、１μｍ毎に目盛を付している。 In FIG. 5, the vertical and horizontal sizes are each 10 μm, the spatial distribution in a region of 10 μm × 10 μm is shown, and a scale is added to each of the x-axis and y-axis for every 1 μm. Yes.
　さらに、図５においては、Ｅｘｃｉｔｅｒ１の位置を黒い星印で示すとともにｓｘ成分及びｓｙ成分の値をカラーバーにより定義している。 Further, in FIG. 5, the position of Excitter 1 is indicated by a black star, and the values of the sx component and the sy component are defined by color bars.
　また、Ｄｅｔｅｃｔｏｒ１，２，３の出力領域にて、スピン波を検出する方法は任意であり、例えば、出力用電極１５から出力される電圧信号に基づいてスピン波を検出するようにしてもよく、他の方法にて、検出するようにしてもよい。 In addition, the method of detecting the spin wave in the output regions of the detectors 1, 2, and 3 is arbitrary. For example, the spin wave may be detected based on the voltage signal output from the output electrode 15. You may make it detect by another method.
　このとき、図５に示すように、ガーネット薄膜１２内では、Ｅｘｃｉｔｅｒ１の領域にて、内径約１．２μｍ、幅約２μｍの円のようなスピン波が励起され、時間とともに広がっていく（伝搬する）様子が観測された。 At this time, as shown in FIG. 5, in the garnet thin film 12, a spin wave such as a circle having an inner diameter of about 1.2 μm and a width of about 2 μm is excited in the region of Exciter 1 and spreads (propagates) with time. ) The situation was observed.
　この場合に励起されるスピン波の振幅は、励起場所（すなわち、Ｅｘｃｉｔｅｒ１）に対して空間的に円対称ではなく、非対称な伝搬特性を有していることが判明した。 It was found that the amplitude of the spin wave excited in this case has an asymmetric propagation characteristic rather than spatially symmetrical with respect to the excitation location (that is, Exciter 1).
　具体的には、図面左右方向に対して、少し斜めに傾いた方向に振幅の大きい領域が生じるとともに、上下には、あまり振幅の大きい領域が生じなかった。 Specifically, a region with a large amplitude was generated in a direction slightly inclined with respect to the horizontal direction of the drawing, and a region with a large amplitude was not generated above and below.
　条件を変化させつつ、Ｅｘｃｉｔｅｒ１の位置にてスピン波を励起させてシミュレーションした結果、非対称性が、１ｓｔの時間長（図４Ａの場合には「３ｎｓ」）に依存しており、１ｓｔの時間長を変化させるとスピン波の形状が変化することが判明した。 While changing the conditions, the result of simulation by exciting a spin wave at the position of Exciter1, asymmetry, 1 time length of st (in the case of FIG. 4A "3ns") is dependent on, 1 st of It was found that the shape of the spin wave changes when the time length is changed.
［４．２．２］スピン波のシミュレーション結果２
　次に、図６を用いて本実施形態の情報処理デバイス１にて励起されるスピン波の干渉についてシミュレーションするため、Ｅｘｃｉｔｅｒ１及び２の位置に２回励起信号を入力して、Ｅｘｃｉｔｅｒ１及び２の領域における一軸磁気異方性Ｋｕを図４（ｂ）のように変化させて、スピン波の干渉をシミュレーションし、その結果を説明する。 [4.2.2] Spin wave simulation result 2
Next, in order to simulate the interference of the spin wave excited by the information processing device 1 of this embodiment with reference to FIG. 6, the excitation signal is input twice at the positions of Exciters 1 and 2, and the areas of Exciters 1 and 2 are input. The uniaxial magnetic anisotropy Ku in FIG. 4 is changed as shown in FIG. 4B to simulate spin wave interference, and the results will be described.
　なお、図６は、本実施形態のシミュレーションにおいてＥｘｃｉｔｅｒ１及び２に設けられた入力用電極に対して２回励起信号を入力した際に励起されるスピン波の空間分布を示す図であり、Ｘ値を「３」、信号入力開始後、７ｎｓ経過したタイミングにおけるｓｘ成分の空間分布を示す図と、Ｘ値を「４」、信号入力開始後、８ｎｓ経過したタイミングにおけるｓｘ成分の空間分布を示す図である。なお、図６は、図５と同様に１０μｍ角の範囲において１μｍ毎に目盛を付している。 FIG. 6 is a diagram showing a spatial distribution of spin waves excited when an excitation signal is input twice to the input electrodes provided in the Exciters 1 and 2 in the simulation of the present embodiment. “3”, a diagram showing the spatial distribution of the sx component at the timing when 7 ns has elapsed after the start of signal input, and a diagram showing the spatial distribution of the sx component at the timing when the X value is “4” and 8 ns have elapsed after starting the signal input It is. Note that FIG. 6 is graduated every 1 μm in the range of 10 μm square as in FIG.
　図６に示すように、スピン波の非対称性に加えてＸ値の変化に伴いＤｅｔｅｃｔｏｒ１，２，３において検出されるスピン波の波形が変化することが観察された。 As shown in FIG. 6, in addition to the asymmetry of the spin wave, it was observed that the waveform of the spin wave detected at the detectors 1, 2, and 3 changes with the change of the X value.
　また、Ｅｘｃｉｔｅｒ１及び２のいずれか一方に２回励起信号入力し、その線形和を行った場合についてもシミュレーションしたが（図示はしない）、図６とは若干異なるスピン波が観測された。このことは、図６に示すスピン波において非線形干渉が起きていることを示唆しているが、この点については、後に詳述する。 In addition, although a simulation was performed in the case where the excitation signal was input twice to either one of the Exciters 1 and 2 and the linear sum thereof was performed (not shown), a spin wave slightly different from that in FIG. 6 was observed. This suggests that non-linear interference occurs in the spin wave shown in FIG. 6, and this point will be described in detail later.
［４．３］スピン波の時間発展について
　次に、図７及び図８を用いてＥｘｃｉｔｅｒ１及び２に対応する入力用電極１４に対して、Ｘ値を「３ｎｓ」とする２回励起信号を入力し、本実施形態の情報処理デバイス１において励起されるスピン波の時間発展についてシミュレーションした結果について説明する。 [4.3] Time evolution of spin wave Next, with reference to FIG. 7 and FIG. 8, a double excitation signal with an X value of “3 ns” is input to the input electrode 14 corresponding to Exciters 1 and 2. A simulation result of the time evolution of the spin wave excited in the information processing device 1 of the present embodiment will be described.
　なお、図７は、スピン波のｓｘ成分及びｓｚ成分の経時変化を示す図である。特に、上から、Ｅｘｃｉｔｅｒ１及び２の領域における一軸磁気異方性Ｋｕの変化状態を示す図、Ｅｘｃｉｔｅｒ１の領域におけるｓｘ成分及びｓｚ成分の経時変化を示す図、Ｄｅｔｅｃｔｏｒ１の領域におけるｓｘ成分及びｓｚ成分の経時変化を示す図、Ｄｅｔｅｃｔｏｒ２の領域におけるｓｘ成分及びｓｚ成分の経時変化を示す図、及び、Ｄｅｔｅｃｔｏｒ３の領域におけるｓｘ成分及びｓｚ成分の経時変化を示す図である。そして、図７においては、ｓｘ成分を赤線にて示すとともに、ｓｚ成分を青線にて示している。 Note that FIG. 7 is a diagram showing temporal changes in the sx component and sz component of the spin wave. In particular, from the top, a diagram showing the change state of the uniaxial magnetic anisotropy Ku in the regions of Exciters 1 and 2, a diagram showing the change over time of the sx component and the sz component in the region of Exciter 1, It is a figure which shows a time-dependent change, a figure which shows a time-dependent change of the sx component and sz component in the area | region of Detector2, and a figure which shows a time-dependent change of the sx component and sz component in the area | region of Detector3. In FIG. 7, the sx component is indicated by a red line, and the sz component is indicated by a blue line.
　また、図８は、本実施形態のシミュレーションにおいてＥｘｃｉｔｅｒ１及び２に対応する入力用電極に２回励起信号を入力した場合に、Ｄｅｔｅｃｔｏｒ１，２，３の領域において検出されるスピン波のｓｘ成分とその包絡線を示す図である。特に、図８の左図は、Ｘ値を「１．５ｎｓ」に設定した状態にて、経過時間数ｔが「８～９ｎｓ」の間に観測されるスピン波のｓｘ成分経時変化と包絡線を示し、図８の右図は、Ｘ値を「４．５ｎｓ」に設定したときに、経過時間数ｔが「８～９ｎｓ」の間に観測されるｓｘ成分の変化と包絡線の関係を示している。また、図８においては、ｓｘ成分を赤線にて示すとともに、その包絡線を黒線にて示している。 FIG. 8 shows the sx component of the spin wave detected in the areas of Detectors 1, 2, and 3 when the excitation signal is input twice to the input electrodes corresponding to Exciters 1 and 2 in the simulation of this embodiment. It is a figure which shows an envelope. In particular, the left diagram of FIG. 8 shows the sx component temporal change and envelope of the spin wave observed when the elapsed time t is “8 to 9 ns” with the X value set to “1.5 ns”. 8 shows the relationship between the change in the sx component and the envelope observed when the elapsed time t is “8 to 9 ns” when the X value is set to “4.5 ns”. Show. In FIG. 8, the sx component is indicated by a red line, and the envelope is indicated by a black line.
　本実施形態のシミュレーションにおいては、図７（上から２番目）に示すように、スピン波の励起は、主に一軸磁気異方性ＫｕがＫｕＬからＫｕＨと変化するタイミングで起きることが分かった。 In the simulation of the present embodiment, as shown in FIG. 7 (second from the top), it is understood that the excitation of the spin wave mainly occurs at the timing when the uniaxial magnetic anisotropy Ku changes from Ku L to Ku H. It was.
　Ｅｘｃｉｔｅｒ１及び２の領域で励起されたスピン波は、ガーネット薄膜１２内を伝搬して、Ｄｅｔｅｃｔｏｒ１，２，３の領域で検出されることになるが、仮に線形干渉が発生しているのであれば、Ｅｘｃｉｔｅｒ１，２から等距離にあるＤｅｔｅｃｔｏｒ１及び３における検出結果は一致するはずである。 The spin waves excited in the areas of Exciters 1 and 2 propagate in the garnet thin film 12 and are detected in the areas of Detectors 1, 2, and 3. If linear interference occurs, The detection results at Detectors 1 and 3 that are equidistant from Exciters 1 and 2 should match.
　しかしながら、図７の上から３番目及び４番目に示すように、Ｄｅｔｅｃｔｏｒ１及び３の領域にて検出されるｓｘ成分及びｓｚ成分の値は、異なっていることが図から読み取れる。 However, as shown in the third and fourth from the top in FIG. 7, it can be seen from the figure that the values of the sx component and the sz component detected in the areas of Detectors 1 and 3 are different.
　このことは、図６及び図８において示したスピン波の空間非対称性が関わっているとともに、スピン波の間に非線形干渉が生じていることを示している。 This indicates that the spatial asymmetry of the spin wave shown in FIGS. 6 and 8 is involved, and that non-linear interference occurs between the spin waves.
　また、本シミュレーションにより、Ｄｅｔｅｃｔｏｒ１，２，３における波形は、Ｅｘｃｉｔｅｒ１又は２のいずれか一方の領域にて得られる波形の和と異なることも判明した。 The simulation also revealed that the waveforms in Detectors 1, 2, and 3 are different from the sum of the waveforms obtained in either region of Exciter 1 or 2.
　また、図８に示すｓｘ成分の包絡線からもＤｅｔｅｃｔｏｒ１及び３において検出されたｓｘ成分が異なることが確認された。 Also, it was confirmed from the envelope of the sx component shown in FIG. 8 that the sx components detected in the detectors 1 and 3 are different.
　さらに、図７の一番目に示すように、このシミュレーション時間中、Ｅｘｃｉｔｅｒにおける一軸磁気異方性ＫｕがＫｕＬ→ＫｕＨとステップするタイミングが、２回ある。この１回目のステップ時に励起されるスピン波と、２回目のステップで励起されるスピン波は、Ｅｘｃｉｔｅｒ、Ｄｅｔｅｃｔｏｒ１，２，３のいずれにおいても異なっていることが図７から読み取れる。 Further, as shown first in FIG. 7, there are two timings during which the uniaxial magnetic anisotropy Ku in the exciter steps from Ku L → Ku H during this simulation time. It can be seen from FIG. 7 that the spin wave excited at the first step and the spin wave excited at the second step are different in each of the Exciter, Detectors 1, 2, and 3.
　これは、以下のような理由に起因するものと考えられる。 This can be attributed to the following reasons.
　具体的には、１回目のステップ時においては、Ｅｘｃｉｔｅｒ以外の領域におけるスピンがほぼ面に垂直方向（＋ｚ方向）を向いていた状態で、スピン波が励起され、伝搬して、各Ｄｅｔｅｃｔｏｒに対応する領域に到達する。 Specifically, at the time of the first step, spin waves are excited and propagated in a state where the spin in the region other than the exciter is oriented substantially perpendicular to the surface (+ z direction), and corresponds to each detector. Reach the area you want.
　一方、２回目のステップ時には、一回目で励起され、伝搬したスピン波によりスピンが既にある程度分布している状態（すなわち、スピンが揺れている、又は、傾いている状態）をスピン波が伝搬して各Ｄｅｔｅｃｔｏｒの領域に到達するため、一回目で励起されるスピン波と二回目で励起されるスピン波では、その伝搬環境に差が生じるということである。 On the other hand, in the second step, the spin wave propagates in a state where the spin is already distributed to some extent by the propagated spin wave (that is, the spin is shaken or tilted). In this case, a difference occurs in the propagation environment between the spin wave excited in the first time and the spin wave excited in the second time.
　この現象は、１回目のステップで励起されたスピン波により、２回目のステップで励起されたスピン波が影響を受けていることを示唆している。すなわち、この現象は、１回目のステップによって励起されたスピン波の励起・伝搬によって、ガーネット薄膜１２のスピンに履歴が残り、この履歴が２回目のステップにより励起されたスピン波に影響を与えていることを意味している。 This phenomenon suggests that the spin wave excited in the second step is affected by the spin wave excited in the first step. That is, this phenomenon has a history in the spin of the garnet thin film 12 due to the excitation and propagation of the spin wave excited by the first step, and this history affects the spin wave excited by the second step. It means that
　通常、原子が持つ大きさが０にはならない自発スピンをもつ磁性体において、スピンは常に何らかの方向を指している。そして、現在のスピンが、入力される信号場（ベクトル）及び到来するスピン波と相互作用して、その原子のスピンの動きが決まり、スピン波が励起・伝搬等する。 Usually, in a magnetic material having a spontaneous spin in which the size of an atom is not zero, the spin always points in some direction. The current spin interacts with the input signal field (vector) and the incoming spin wave to determine the spin movement of the atom, and the spin wave is excited and propagated.
　また、磁性体においては、過去にスピン波が励起され、又は、伝搬した場合に、過去におけるスピン波の励起・伝搬の履歴によって決定される現在のスピン状態が、信号場とともに相互作用を決定する。 In a magnetic material, when a spin wave is excited or propagated in the past, the current spin state determined by the history of excitation and propagation of the spin wave in the past determines the interaction with the signal field. .
　このため、ガーネット薄膜１２内をスピン波が伝搬すると、どのような順番で、どのような信号が入力されたのかが、スピンの分布状態として残留し、後に入力される信号の出力結果を変化させる。 For this reason, when a spin wave propagates in the garnet thin film 12, what kind of signal is inputted in what order remains as a spin distribution state, and changes the output result of a signal inputted later. .
　ニューラルネットワークにおいては、全入力信号に対する重み付け総和をとる処理を行う例が多いが、本実施形態の情報処理デバイス１は、過去に入力された入力信号の履歴に応じて、出力信号を変化させることができるとともに、各信号の相互作用を通して新たなスピン波を形成することができるのでメモリを併設することなく、過去の記憶の重み付け総和をとる演算を行う際にも、高い適応性を発揮することができる。 In a neural network, there are many examples in which processing for calculating a weighted sum for all input signals is performed. However, the information processing device 1 according to the present embodiment changes an output signal according to a history of input signals input in the past. In addition, since a new spin wave can be formed through the interaction of each signal, it is highly adaptable even when performing operations that calculate the weighted sum of past memories without using a memory. Can do.
　この結果、本実施形態の情報処理デバイス１は、規模を増大させることなく、ニューラルネットワークに対する高い適応性を確保できるリザバーとして利用することができる。 As a result, the information processing device 1 of this embodiment can be used as a reservoir that can ensure high adaptability to the neural network without increasing the scale.
　また、ガーネット薄膜１２は、スピンの特性（例えば、スピンの向きや分布等）が、位置に応じて異なるという特性を有しているので、本実施形態の情報処理デバイス１においては、出力領域から出力される電気信号が、入力用電極１４及び出力用電極１５の入出力面１３２における面内位置に応じて変化する。 Further, since the garnet thin film 12 has a characteristic that spin characteristics (for example, spin direction and distribution) differ depending on the position, in the information processing device 1 of the present embodiment, from the output region. The output electrical signal changes in accordance with the in-plane positions of the input electrode 14 and the output electrode 15 on the input / output surface 132.
　例えば、本実施形態の情報処理デバイス１は、同じ面内位置から同じ電気信号が入力された場合においても、出力領域の面内位置が異なると、異なる信号が出力される。 For example, even when the same electrical signal is input from the same in-plane position, the information processing device 1 of the present embodiment outputs a different signal if the in-plane position of the output region is different.
　さらに、本実施形態の情報処理デバイス１においては、同じ出力用電極１５から出力される信号であっても入力用電極１４の面内位置が異なると違う信号が出力される。 Furthermore, in the information processing device 1 of this embodiment, even if the signals are output from the same output electrode 15, different signals are output if the in-plane position of the input electrode 14 is different.
　また、本実施形態の情報処理デバイス１においては、過去の入力信号に基づき励起・伝搬した、スピン波の履歴が、出力信号に反映されるので、信号の入力タイミングが異なると、同じ面内位置から同じ信号を入力し、かつ、同じ面内位置から信号を出力させる場合においても、違う信号が出力される。 In the information processing device 1 according to the present embodiment, the history of spin waves excited and propagated based on past input signals is reflected in the output signal. Even when the same signal is input from and the signals are output from the same in-plane position, different signals are output.
　この結果、本実施形態の情報処理デバイス１は、多数の入力信号に対して、多種多様な出力バリエーションを実現できるので、ニューラルネットワークを実現する際においても、高い適応性を有するリザバーとして利用することができる。 As a result, the information processing device 1 of the present embodiment can realize a wide variety of output variations with respect to a large number of input signals, so that it can be used as a highly adaptable reservoir even when realizing a neural network. Can do.
［４．３］リザバーコンピューティングのシミュレーション結果
　次に、図９を用いて本実施形態の情報処理デバイス１を用いたリザバーコンピューティングのシミュレーション結果について説明する。 [4.3] Simulation Results of Reservoir Computing Next, simulation results of reservoir computing using the information processing device 1 of the present embodiment will be described with reference to FIG.
　なお、図９は、本実施形態の情報処理デバイスを用いたリザバーコンピューティングのシミュレーション結果を示す図である。 FIG. 9 is a diagram showing a simulation result of the reservoir computing using the information processing device of the present embodiment.
　本シミュレーションは、上記の情報処理デバイス１において、Ｅｘｃｉｔｅｒに対応する入力用電極１４に対して、それぞれ、Ｘ値の異なる複数種類の２回励起信号を入力し、非線形干渉を生じるスピン波を励起させた場合であって、当該励起されたスピン波を用いて、外部回路にて、各入力信号のＸ値を推定した場合のシミュレーションである。 In this information processing device 1, in the information processing device 1 described above, a plurality of types of twice-excitation signals having different X values are input to the input electrode 14 corresponding to Exciter to excite spin waves that cause nonlinear interference. This is a simulation when the X value of each input signal is estimated by an external circuit using the excited spin wave.
　具体的には、本シミュレーションにおいては、まず、Ｘ値を「１．５ｎｓ」、「２．５ｎｓ」、「３．５ｎｓ」、「４．５ｎｓ」とした既知の２回励起信号（図７参照）をトレーニングデータとしてＥｘｃｉｔｅｒ１及び２に対応する入力用電極１４に入力した。 Specifically, in this simulation, first, a known double excitation signal with an X value of “1.5 ns”, “2.5 ns”, “3.5 ns”, and “4.5 ns” (see FIG. 7). ) Was input to the input electrodes 14 corresponding to Exciters 1 and 2 as training data.
　そして、２回励起信号の入力開始タイミングからの経過時間数ｔが８ｎｓとなったタイミングから９ｎｓとなるまで１ｎｓの間、各Ｄｅｔｅｃｔｏｒに対応する出力用電極１５から出力される出力信号を外部回路に入力して、当該出力信号に基づき、外部回路にＸ値の推定方法を学習させた。 The output signal output from the output electrode 15 corresponding to each detector is output to the external circuit for 1 ns from the timing when the elapsed time t from the input start timing of the twice excitation signal becomes 8 ns to 9 ns. Based on the output signal, the external circuit was made to learn the X value estimation method.
　このとき、出力信号に基づくＸ値の推定値が、既知のＸ値（すなわち、トレーニングデータのＸ値）となるように出力信号に対して、最適な重み付けを行うための学習（すなわち、パラメータフィッティング）を外部回路に行わせた。 At this time, learning for optimum weighting of the output signal (that is, parameter fitting) so that the estimated value of the X value based on the output signal becomes a known X value (that is, the X value of the training data). ) Was performed by an external circuit.
　そして、この学習の後、Ｘ値が未知の２回励起信号（具体的には、Ｘ値が「２．０ｎｓ」、「３．０ｎｓ」、「４．０ｎｓ」、となっている２回励起信号）を、Ｅｘｃｉｔｅｒ１及び２に対応する入力用電極１４に入力して、出力信号に基づくＸ値の推定を外部回路に行わせた。 After this learning, a double excitation signal whose X value is unknown (specifically, a double excitation in which the X value is “2.0 ns”, “3.0 ns”, “4.0 ns”) Signal) is input to the input electrodes 14 corresponding to Exciters 1 and 2, and the external circuit estimates the X value based on the output signal.
　以上のようにトレーニングデータ及び未知の２回励起信号をＥｘｃｉｔｅｒ１及び２に入力した際に、外部回路にて推定されたＸ値と、実際に入力した２回励起信号におけるＸ値との関係をプロットしたところ図９のような結果が得られた。 As described above, when the training data and the unknown double excitation signal are input to the Exciters 1 and 2, the relationship between the X value estimated by the external circuit and the X value in the actually input double excitation signal is plotted. As a result, a result as shown in FIG. 9 was obtained.
　なお、図９は、本実施形態の情報処理デバイス１を用いたリザバーコンピューティングのシミュレーション結果を示す図であり、実際に入力した２回励起信号のＸ値を横軸、出力信号から外部回路が推定したＸ値を縦軸に設定している。 FIG. 9 is a diagram showing a simulation result of the reservoir computing using the information processing device 1 of the present embodiment. The X value of the actually input double excitation signal is shown on the horizontal axis, and the external circuit determines from the output signal. The estimated X value is set on the vertical axis.
　また、図９において０点から伸びる斜めの線は、実際に入力した２回励起信号におけるＸ値と、出力信号から推定されるＸ値が一致する点を結んだ線であり、この線に近ければ近いほど、実際のＸ値と推定されたＸ値の誤差が小さいことを示している。 In FIG. 9, the diagonal line extending from the zero point is a line connecting the points where the X value in the actually inputted double excitation signal and the X value estimated from the output signal coincide with each other. The closer it is, the smaller the error between the actual X value and the estimated X value is.
　さらに、図９においてはトレーニングデータに基づく推定結果を青い四角形にて示すとともに、Ｘ値が未知の２回励起信号が入力された際におけるＸ値の推定結果を赤丸にて示している 。 Furthermore, in FIG. 9, the estimation result based on the training data is indicated by a blue square, and the estimation result of the X value when a double excitation signal with an unknown X value is input is indicated by a red circle.
　図９に示すように外部回路におけるＸ値の推定結果は、トレーニングデータのみならず、Ｘ値が未知の２回励起信号に関しても、実際のＸ値と推定値が低い誤差で一致することが確認された。 As shown in FIG. 9, it is confirmed that the estimation result of the X value in the external circuit matches the actual X value and the estimated value with a low error not only for the training data but also for the double excitation signal whose X value is unknown. It was done.
　すなわち、本実施形態の情報処理デバイス１によれば、未学習の入力信号に対しても、小さな誤差囲内で適切な推定値を与えることが実証された。 That is, according to the information processing device 1 of the present embodiment, it has been demonstrated that an appropriate estimated value is given within a small error range even for an unlearned input signal.
　この未学習の入力に対して、適切な推定値を与える能力は、汎化能力と呼ばれる。 The ability to give an appropriate estimate for this unlearned input is called generalization ability.
　本実施形態の情報処理デバイス１は、信号を高次元空間に変換（写像）することが可能であり、その出力を用いて外部回路において学習を成功させ、未学習の信号が入力された場合にも、最も確からしい値を高い精度で推定できる汎化能力を実現できる。 The information processing device 1 according to the present embodiment can convert (mapping) a signal into a high-dimensional space, and when learning is successful in an external circuit using the output, and an unlearned signal is input However, the generalization ability that can estimate the most probable value with high accuracy can be realized.
　すなわち、本実施形態の情報処理デバイス１は、未知の信号が入力された場合にも、外部回路にて高精度な推定を実現できる。 That is, the information processing device 1 of the present embodiment can realize high-precision estimation with an external circuit even when an unknown signal is input.
　この汎化能力は、リザバーコンピューティングの特長であり、未学習の信号が入力された場合にも、外部回路におけるパラメータ・ フィッティングを成功させるために有効な高次元空間への変換（写像）を実現できる機能が求められる。 This generalization capability is a feature of reservoir computing, and even when an unlearned signal is input, conversion (mapping) to a high-dimensional space effective for successful parameter / fitting in an external circuit is realized. Capable functions are required.
　したがって、以上のシミュレーション結果から、本実施形態の情報処理デバイス１は、高い精度でリザバーコンピューティングを実現できる高次元空間への写像が可能であることが実証された。 Therefore, from the above simulation results, it was proved that the information processing device 1 of the present embodiment can be mapped to a high-dimensional space that can realize reservoir computing with high accuracy.
　なお、図９は、Ｅｘｃｉｔｅｒ１及び２に対応する入力用電極１４に２回励起信号を入力して励起されたスピン波を干渉させた場合に、経過時間数ｔ＝８～９ｎｓの１ｎｓの間に得られるスピン波を用いてＸ値を推定した結果を示すものであった。 Note that FIG. 9 shows that when an excitation signal is input twice to the input electrodes 14 corresponding to Exciters 1 and 2 to cause the excited spin wave to interfere with each other, the elapsed time t = 8 to 9 ns during 1 ns. The result of estimating the X value using the obtained spin wave was shown.
［４．４］シミュレーションにおける条件の違いがコンピューティングに与える影響について
　次に、図１０Ａ及び図１０Ｂを用いて本実施形態の情報処理デバイス１を用いたリザバーコンピューティングにおける条件の違いがコンピューティングに与える影響について説明する。 [4.4] Effects of Differences in Simulation Conditions on Computing Next, differences in conditions in the reservoir computing using the information processing device 1 of the present embodiment will be described in FIG. 10A and FIG. 10B. The effect will be described.
　なお、図１０Ａ及び図１０Ｂは、本実施形態のシミュレーション結果を示す図である。特に、図１０Ａは、Ｅｘｃｉｔｅｒ１及び２に対応する入力用電極に対して２回励起信号を入力した際におけるＲＭＳＥの分布を示す図であり、図１０Ｂは、Ｅｘｃｉｔｅｒ１に対応する入力用電極１４に対してのみ２回励起信号を入力した際におけるＲＭＳＥ（Ｒｏｏｔ　Ｍｅａｎ　Ｓｑｕａｒｅ　Ｅｒｒｏｒｓ：二乗平均平方根誤差）の分布を示す図である。 FIG. 10A and FIG. 10B are diagrams showing simulation results of the present embodiment. In particular, FIG. 10A is a diagram showing a distribution of RMSE when an excitation signal is input twice to the input electrodes corresponding to Exciters 1 and 2, and FIG. 10B shows the input electrode 14 corresponding to Exciter 1. It is a figure which shows distribution of RMSE (Root Mean Square Errors: the root mean square error) at the time of inputting an excitation signal only twice.
　本シミュレーションは、上記の情報処理デバイス１において、上記図９における条件（すなわち、Ｅｘｃｉｔｅｒ１及び２に同時にスピン波を励起させ、経過時間数ｔが８～９ｎｓとする条件）を変更しつつ、外部回路にて入力信号のＸ値を推定した場合のシミュレーションである。 In the information processing device 1, the present simulation changes the conditions in FIG. 9 (that is, the conditions in which the exciters 1 and 2 are simultaneously excited with spin waves and the elapsed time t is 8 to 9 ns) while changing the external circuit. It is a simulation at the time of estimating the X value of an input signal.
　すなわち、本シミュレーションは、図９の条件に基づいた上記のシミュレーション結果において、Ｘ値の推定結果と、実際に入力された２回励起信号のＸ値が概ね一致する結果が得られたが、これらの条件が正しい推定結果を得るための必要条件であるか否かを確認するためのシミュレーションである。 That is, in this simulation, in the above simulation results based on the conditions of FIG. 9, the X value estimation result and the X value of the actually input double excitation signal almost coincided with each other. This is a simulation for confirming whether or not the above condition is a necessary condition for obtaining a correct estimation result.
　具体的には、本シミュレーションにおいて、上記図９における条件が、
（１）２回励起信号をＥｘｃｉｔｅｒ１のみに入力した場合、
（２）経過時間数ｔの開始タイミングを変更した場合、及び、
（３）経過時間数ｔの観測対象時間長 （以下、「ｄｕｒａｔｉｏｎ」ともいう。）を変化させた場合、
の各場合について網羅的に検証した。 Specifically, in this simulation, the condition in FIG.
(1) When the excitation signal is input twice only to Exciter1,
(2) When the start timing of the elapsed time t is changed, and
(3) When the observation target time length of the elapsed time t (hereinafter also referred to as “duration”) is changed,
Each case was comprehensively verified.
（ａ）経過時間数ｔ及び観測対象時間長が与える影響について
　まず、上記（２）及び（３）の影響をシミュレーションするため、Ｅｘｃｉｔｅｒ１及び２に対応する入力用電極１４に２回励起信号を同時入力し（すなわち、図９と同一条件）、経過時間数ｔの時間範囲（すなわち、経過時間数ｔのスタートタイミング及びｄｕｒａｔｉｏｎ）を変化させた。 (A) Regarding the influence of the elapsed time t and the observation target time length First, in order to simulate the influence of the above (2) and (3), two excitation signals are simultaneously applied to the input electrodes 14 corresponding to Exciters 1 and 2. Input (that is, the same conditions as in FIG. 9), and the time range of elapsed time t (that is, start timing and duration of elapsed time t) was changed.
　そして、各場合に、出力信号から推定されたＸ値と実際に入力された２回励起信号におけるＸ値に基づき、ＲＭＳＥを算出し、ＲＭＳＥの算出結果と開始タイミング及びｄｕｒａｔｉｏｎの関係をプロットしたところ、図１０Ａのような結果が得られた。 In each case, the RMSE is calculated based on the X value estimated from the output signal and the X value in the actually input double excitation signal, and the relationship between the RMSE calculation result and the start timing and duration is plotted. The result as shown in FIG. 10A was obtained.
　また、図１０Ａに示すように、図９のシミュレーション条件（すなわち、開始タイミング=８ｎｓ、ｄｕｒａｔｉｏｎ＝１ｎｓ）が最もＲＭＳＥが小さいことが判明した。 Further, as shown in FIG. 10A, it was found that the RMSE is the smallest under the simulation conditions of FIG. 9 (that is, start timing = 8 ns, duration = 1 ns).
（ｂ）Ｅｘｃｉｔｅｒの領域で励起されるスピン波の影響について
　次に、Ｅｘｃｉｔｅｒの領域で励起されるスピン波がコンピューティングに与える影響をシミュレーションするため、Ｘ値を「１．５ｎｓ」、「２．５ｎｓ」、「３．５ｎｓ」、「４．５ｎｓ」とした２回励起信号（トレーニングデータ）をＥｘｃｉｔｅｒ１に対応する入力用電極１４のみに入力して、外部回路にて、上記と同様の学習を行わせた後、Ｅｘｃｉｔｅｒ１に対応する入力用電極１４にのみ２回励起信号を入力した。 (B) Effect of Spin Wave Excited in Exciter Region Next, in order to simulate the influence of the spin wave excited in the Exciter region on computing, the X value is set to “1.5 ns”, “2. The second excitation signal (training data) set to “5 ns”, “3.5 ns”, and “4.5 ns” is input only to the input electrode 14 corresponding to Exciter 1 and learning similar to the above is performed in an external circuit. After being performed, the excitation signal was input twice only to the input electrode 14 corresponding to Exciter1.
　そして、開始タイミング及びｄｕｒａｔｉｏｎの影響をシミュレーションするため開始タイミング及びｄｕｒａｔｉｏｎを変化させつつ、外部回路にて推定されるＸ値と、実際の入力信号に対応するＸ値に基づきＲＭＳＥを算出し、各場合におけるＲＭＳＥをプロットした結果、図１０Ｂのような結果が得られた。 Then, in order to simulate the influence of the start timing and duration, the RMSE is calculated based on the X value estimated by the external circuit and the X value corresponding to the actual input signal while changing the start timing and duration. As a result of plotting the RMSE, the result as shown in FIG. 10B was obtained.
　特に、図１０Ａ及び図１０Ｂに示すようにＥｘｃｉｔｅｒ１に対応する入力用電極１４のみに２回励起信号を入力した場合には、Ｅｘｃｉｔｅｒ１及び２に対応する入力用電極１４に２回励起信号を入力した場合と比較して、全ての条件で誤差が大きくなることが判明した。 In particular, as shown in FIGS. 10A and 10B, when the excitation signal is input twice only to the input electrode 14 corresponding to Exciter1, the excitation signal is input twice to the input electrode 14 corresponding to Exciter1 and 2. It was found that the error was larger under all conditions compared to the case.
　以上のミュレーション結果から、Ｅｘｃｉｔｅｒ１及び２に対応する入力用電極１４対して、２回励起信号を同時に入力し、非線形干渉を起こすスピン波を励起させることが、推定結果の正確性を向上させ、リザバーコンピューティングに対する高い適応性を確保する上で、非常に重要であることが判明した。 From the above simulation results, it is possible to simultaneously input the excitation signal twice to the input electrodes 14 corresponding to Exciters 1 and 2 and excite spin waves that cause nonlinear interference, thereby improving the accuracy of the estimation results, It turned out to be very important in ensuring high adaptability to reservoir computing.
　また、当該シミュレーション結果から、非対称かつ非線形干渉を起こすスピン波を励起できる本実施形態の情報処理デバイス１がリザバーコンピューティングに高い適応性を有することが確認された。 Also, from the simulation results, it was confirmed that the information processing device 1 of the present embodiment that can excite spin waves that cause asymmetric and nonlinear interference has high adaptability to reservoir computing.
［５］変形例
［５．１］変形例１
　上記実施形態においては、情報処理デバイス１単体で、入力信号を変換して出力する構成について説明したが、ニューラルネットワークを実現するため、外部回路と組み合わせて１つのシステム（すなわち、リザバーコンピューティングを実現するシステム）を構成するようにしてもよい。 [5] Modification [5.1] Modification 1
In the above embodiment, the configuration in which the information processing device 1 alone converts and outputs an input signal has been described. However, in order to realize a neural network, a single system (that is, reservoir computing is realized in combination with an external circuit). System).
［５．２］変形例２
　次に、図１１、図１２Ａ～図１２Ｃ、図１３Ａ及び図１３Ｂを用いて、本発明の変形例２について説明する。なお、図１１は、本変形例における情報処理デバイス１の構成を示す図であり、図１２Ａ～図１２Ｃ、図１３Ａ及び図１３Ｂは、ビアホール内部の構成を示す断面図である。 [5.2] Modification 2
Next, a second modification of the present invention will be described with reference to FIGS. 11, 12A to 12C, 13A, and 13B. FIG. 11 is a diagram showing the configuration of the information processing device 1 in the present modification, and FIGS. 12A to 12C, FIGS. 13A and 13B are cross-sectional views showing the configuration inside the via hole.
　上記実施形態においては、磁電カップリング層１３として加工のない平面構造のものを用いる構成を採用しているが、本変形例の情報処理デバイス１においては、図１１に示すように、磁電カップリング層１３において入力用電極１４及び出力用電極１５の設置領域直下にビアホール１６を設ける構成を採用してもよい。 In the above-described embodiment, a configuration using a planar structure without processing as the magnetoelectric coupling layer 13 is adopted. However, in the information processing device 1 of this modification, as shown in FIG. A configuration in which the via hole 16 is provided in the layer 13 immediately below the installation region of the input electrode 14 and the output electrode 15 may be employed.
　具体的には、各ビアホール１６には、他の材料を埋め込み、素子を作り込む構成を有している。また、ビアホール１６内の具体的な構成としては、図１２Ａ～図１２Ｃ、並びに、図１３Ａ及び図１３Ｂのような５通りの構成を採用することができる。 Specifically, each via hole 16 has a configuration in which another material is embedded to form an element. Further, as a specific configuration in the via hole 16, five configurations as shown in FIGS. 12A to 12C and FIGS. 13A and 13B can be adopted.
＜構成パターン１＞
　この構成は、図１２Ａに示すようにビアホール１６内において、磁電カップリング層１３と接する部位に絶縁膜を設け、絶縁膜に峡持される領域に、強誘電体を埋め込む構成である。 <Configuration pattern 1>
In this configuration, as shown in FIG. 12A, an insulating film is provided in a portion in contact with the magnetoelectric coupling layer 13 in the via hole 16, and a ferroelectric is embedded in a region held by the insulating film.
　この構成を採用した場合には、入出力として電圧信号を用いることが必要となる。そして、入力用電極１４に電圧信号が入力されると、入力用電極１４直下の磁気異方性が変化して、スピン波が励起され、伝搬し、出力領域にて再度電圧信号に変換されて出力用電極１５から出力されることとなる。 When this configuration is adopted, it is necessary to use voltage signals as input and output. When a voltage signal is input to the input electrode 14, the magnetic anisotropy immediately below the input electrode 14 changes, the spin wave is excited, propagates, and is converted back to a voltage signal in the output region. It is output from the output electrode 15.
　なお、この構成により、電束の面内に対する広がりが抑えられ、効率の良い変換が実現することができる。 In addition, with this configuration, the spread of the electric flux in the plane can be suppressed, and efficient conversion can be realized.
＜構成パターン２＞
　この構成は、図１２Ｂに示すようにビアホール１６内において、磁電カップリング層１３と接する部位に絶縁膜を設け、絶縁膜に峡持される領域に、圧電体を埋め込む構成である。 <Configuration pattern 2>
In this configuration, as shown in FIG. 12B, an insulating film is provided in a portion in contact with the magnetoelectric coupling layer 13 in the via hole 16, and a piezoelectric body is embedded in a region held by the insulating film.
　この構成を採用した場合にも、入出力には電圧信号を用いることが必要となる。そして、入力用電極１４に電圧信号が入力されると、入力用電極１４直下の圧電体が変形し、入力領域にてガーネット薄膜１２の一軸磁気異方性Ｋｕが変化してスピン波が励起され、出力用電極１５から電圧信号が出力される。 Even when this configuration is adopted, it is necessary to use voltage signals for input and output. When a voltage signal is input to the input electrode 14, the piezoelectric body immediately below the input electrode 14 is deformed, and the uniaxial magnetic anisotropy Ku of the garnet thin film 12 is changed in the input region to excite a spin wave. A voltage signal is output from the output electrode 15.
　この構成により、電束の面内に対する広がりを抑制し、圧電体の体積変化の逃げも少なくできるので電圧信号とスピン波の間の変換を行う際のエネルギー損失を低減させることができる。 With this configuration, the spread of the electric flux in the plane can be suppressed, and the escape of volume change of the piezoelectric body can be reduced, so that energy loss when converting between the voltage signal and the spin wave can be reduced.
＜構成パターン３＞
　この構成は、図１２Ｃに示すようにビアホール１６内において、磁電カップリング層１３と接する部位に絶縁膜を設け、絶縁膜に峡持される領域に、逆磁歪強磁性体と圧電体を積層して埋め込む構成である。 <Configuration pattern 3>
In this configuration, as shown in FIG. 12C, in the via hole 16, an insulating film is provided at a portion in contact with the magnetoelectric coupling layer 13, and an inverse magnetostrictive ferromagnetic material and a piezoelectric material are laminated in a region held by the insulating film. And embedded.
　この構成を採用した場合においても、入出力には電圧信号を用いることが必要となる。そして、入力用電極１４に電圧信号が入力されると、入力用電極１４直下領域にて圧電体が変形する。また、圧電体の体積変化を、高い磁気歪みをもつ逆磁歪強磁性体材料のスピン方向変化に変換する。そして、このスピンからの漏えい磁場、或いは、層を越えたスピン間交換相互作用をガーネット薄膜１２が受け、入力領域にてスピン波が励起され、伝搬して、出力用電極１５から電圧信号が出力される。 Even when this configuration is adopted, it is necessary to use voltage signals for input and output. When a voltage signal is input to the input electrode 14, the piezoelectric body is deformed in a region immediately below the input electrode 14. Further, the volume change of the piezoelectric body is converted into a spin direction change of the inverse magnetostrictive ferromagnetic material having high magnetostriction. The garnet thin film 12 receives the leakage magnetic field from the spin or the spin-to-spin exchange interaction beyond the layer, the spin wave is excited in the input region, propagates, and a voltage signal is output from the output electrode 15. Is done.
　すなわち、本構成においては、磁気的相互作用、或いは、局所電子間相互作用を利用してスピン波が励起される。 That is, in this configuration, the spin wave is excited by using magnetic interaction or local electron interaction.
　この構成により、電圧信号とスピン波を相互変換する際のエネルギー効率を向上させることが可能となる。 This configuration makes it possible to improve the energy efficiency when the voltage signal and the spin wave are mutually converted.
＜構成パターン４＞
　この構成は、図１３Ａに示すようにビアホール１６内において、磁電カップリング層１３と接する部位に絶縁膜を設け、絶縁膜に峡持される領域に、重金属を充填する構成である。 <Configuration pattern 4>
In this configuration, as shown in FIG. 13A, an insulating film is provided in a portion in contact with the magnetoelectric coupling layer 13 in the via hole 16, and a region held by the insulating film is filled with heavy metal.
　この構成を採用する場合には、図１３Ａに示すように絶縁膜に峡持される領域に絶縁膜により構成される隔離壁を設ける。 When this configuration is adopted, as shown in FIG. 13A, an isolation wall made of an insulating film is provided in a region held by the insulating film.
　また、本構成の場合には、重金属として、タンタル（Ｔａ）、タングステン（Ｗ）、白金（Ｐｔ） などを用いることができる。 In the case of this configuration, tantalum (Ta), tungsten (W), platinum (Pt), or the like can be used as the heavy metal.
　さらに、本構成の場合には、入力を電流信号により行い、出力は電圧信号により行うことが必要となる。 Furthermore, in this configuration, it is necessary to input with a current signal and output with a voltage signal.
　一方、本構成では、入力用電極１４及び出力用電極１５をそれぞれ、２つの端子により構成することが必要となる。 On the other hand, in this configuration, it is necessary to configure the input electrode 14 and the output electrode 15 respectively by two terminals.
　重金属は、スピン軌道相互作用が大きいためスピン偏極電子流を生成できる。そして、本構成では、重金属を流れる電流の向きに応じて、ガーネット薄膜１２表面に流れるスピンの向きを変化させることでスピン波が励起され、伝搬して、出力用電極１５から電圧信号が出力される。 Heavy metals can generate spin-polarized electron current because of their large spin-orbit interaction. In this configuration, the spin wave is excited and propagated by changing the direction of the spin flowing on the surface of the garnet thin film 12 according to the direction of the current flowing through the heavy metal, and a voltage signal is output from the output electrode 15. The
　この構成により、スピン波を伝搬する強磁性体と圧電体との変換効率を高めることができ、電気信号とスピン波を相互変換する際のエネルギー効率を向上させることが可能となる。 With this configuration, the conversion efficiency between the ferromagnetic material and the piezoelectric material that propagates the spin wave can be increased, and the energy efficiency when the electrical signal and the spin wave are mutually converted can be improved.
＜構成パターン５＞
　この構成は、図１３Ｂに示すようにビアホール１６内において、磁電カップリング層１３と接する部位に絶縁膜を設け、絶縁膜に峡持される領域に、強磁性体と、トンネル磁性膜、金属配線を積層する構成である。 <Configuration pattern 5>
In this configuration, as shown in FIG. 13B, in the via hole 16, an insulating film is provided in a portion in contact with the magnetoelectric coupling layer 13, and a ferromagnetic material, a tunnel magnetic film, and a metal wiring are provided in a region held by the insulating film. It is the structure which laminates | stacks.
　この構成によれば、強磁性トンネル接合により、スピン波を励起することができる。なお、強磁性トンネル接合とは、強磁性体、トンネル絶縁膜、強磁性体から成る三層構造で上部下部の磁性体のスピン方向によって抵抗が変化する素子のことである。 According to this configuration, the spin wave can be excited by the ferromagnetic tunnel junction. The ferromagnetic tunnel junction is an element having a three-layer structure composed of a ferromagnetic material, a tunnel insulating film, and a ferromagnetic material, the resistance of which changes depending on the spin direction of the upper and lower magnetic materials.
　また、この構成では、強磁性体は導電のものを用いることが必要になり、入出力をともに、電流信号により行うことが必要となる。 In this configuration, it is necessary to use a conductive ferromagnetic material, and both input and output must be performed by a current signal.
　さらに、この構成では、出力側に直流バイアス電流を印加した構成とする。この構成により出力領域におけるスピンの動きを検出することができる。 Furthermore, in this configuration, a DC bias current is applied to the output side. With this configuration, the spin motion in the output region can be detected.
　また、この構成では、入力用電極１４及び出力用電極１５をそれぞれ、２つの端子により構成することが必要となる。 In this configuration, the input electrode 14 and the output electrode 15 must each be composed of two terminals.
　そして、この構成により、磁気的相互作用、あるいは局所電子間相互作用を利用することで、電流の向きによってトンネル接合下部の強磁性体のスピンが歳差運動をして、このスピンからの漏えい磁場、或いは、層を越えたスピン間交換相互作用をガーネット薄膜１２が受けて、スピン波が励起され、伝搬して、出力用電極１５から電流信号が出力されることとなる。 And by using this structure, the spin of the ferromagnet below the tunnel junction precesses depending on the direction of the current by utilizing magnetic interaction or local electron interaction, and the leakage magnetic field from this spin Alternatively, the garnet thin film 12 receives the exchange interaction between the spins beyond the layer, the spin wave is excited and propagated, and a current signal is output from the output electrode 15.
　また、この構成により、直流電流で共振現象を起こすことが可能であり、直流－交流変換として、スピン波の励起を交流入力で永続的に持続させることも期待できる。 Also, with this configuration, it is possible to cause a resonance phenomenon with a direct current, and it can be expected that excitation of a spin wave is sustained permanently with an alternating current input as a direct current to alternating current conversion.
［５．３］変形例３
　上記実施形態においては、ガーネット薄膜１２により情報処理デバイス１を構成したが、強磁性体金属合金、強磁性酸化物、フェリ磁性体等、強磁性共鳴やスピン波を誘起可能な材質であれば、何を用いて情報処理デバイス１を構成するようにしてもよい。 [5.3] Modification 3
In the above embodiment, the information processing device 1 is configured by the garnet thin film 12. However, any material that can induce ferromagnetic resonance and spin waves, such as a ferromagnetic metal alloy, a ferromagnetic oxide, and a ferrimagnetic material, The information processing device 1 may be configured using anything.
　すなわち、入力用電極１４に対して、電気信号が入力された際に、磁電カップリング層１３により、局所的な物理特性が変化して、スピン波を励起可能なものであれば、何を利用してもよい。 In other words, when an electrical signal is input to the input electrode 14, what can be used as long as the local physical characteristics are changed by the magnetoelectric coupling layer 13 to excite spin waves. May be.
１　・・・　情報処理デバイス
１１　・・・　導電性基板
１２　・・・　ガーネット薄膜
１３　・・・　磁電カップリング層
１４　・・・　入力用電極
１５　・・・　出力用電極
１６　・・・　ビアホール
１３１　・・・　界面
１３２　・・・　入出力面 DESCRIPTION OF SYMBOLS 1 ... Information processing device 11 ... Conductive substrate 12 ... Garnet thin film 13 ... Magnetoelectric coupling layer 14 ... Input electrode 15 ... Output electrode 16 ... Via hole 131 ...・ Interface 132 ... Input / output surface

Claims (9)

  1. 　基準電圧に維持される第１構造層と、
    　前記第１構造層上に形成される第２構造層と、
    　前記第２構造層上に形成され、前記第２構造層に接する面と反対側の面が信号の入出力面となる第３構造層と、
    　を有し、
    　前記第３構造層が、
    　　前記入出力面のいずれの場所にも形成可能な電極であって、所定の電気信号が入力信号として入力される１以上の第１電極と、
    　　前記第１電極が形成された場所を除き、前記入出力面のいずれの場所にも形成可能な電極であって、所定の電気信号が出力信号として出力される１以上の第２電極と、
    　を備え、
    　前記第２構造層が、
    　　前記第１電極に対して所定の電気信号が入力信号として入力された場合に、前記第１電極に対応する第１領域にてスピン波を励起し、かつ、前記第２電極に対応する第２領域に前記スピン波を伝搬させる構造を有し、
    　前記第１領域と前記第２領域の位置に応じて、前記スピン波の特性が異なることを特徴とする情報処理デバイス。     A first structural layer maintained at a reference voltage;
    A second structural layer formed on the first structural layer;
    A third structural layer formed on the second structural layer, the surface opposite to the surface in contact with the second structural layer being a signal input / output surface;
    Have
    The third structure layer is
    One or more first electrodes that can be formed at any place on the input / output surface, and a predetermined electrical signal is input as an input signal;
    One or more second electrodes that can be formed at any location on the input / output surface except for the location where the first electrode is formed, and that output a predetermined electrical signal as an output signal;
    With
    The second structural layer comprises:
    When a predetermined electrical signal is input as an input signal to the first electrode, a spin wave is excited in the first region corresponding to the first electrode, and a second corresponding to the second electrode Having a structure for propagating the spin wave in a region;
    An information processing device, wherein the characteristics of the spin wave differ depending on the positions of the first region and the second region.
  2. 　前記入出力面に対して任意の方向に、所定値の直流外部磁場を印加する磁場印加手段をさらに備える、請求項１に記載の情報処理デバイス。 The information processing device according to claim 1, further comprising magnetic field applying means for applying a DC external magnetic field having a predetermined value in an arbitrary direction with respect to the input / output surface.
  3. 　前記入力信号が入力され、前記スピン波が前記第２構造層を伝搬した場合に、
    　その履歴がスピンの分布状態として残留し、その後に入力される前記入力信号に対する前記出力信号の信号値を前記履歴に基づき変化させる、請求項１又は２に記載の情報処理デバイス。     When the input signal is input and the spin wave propagates through the second structure layer,
    The information processing device according to claim 1, wherein the history remains as a spin distribution state, and the signal value of the output signal with respect to the input signal input thereafter is changed based on the history.
  4. 　前記第３構造層が、
    　　前記第１電極及び前記第２電極の形成された領域にビアホールを有し、当該ビアホール内に他の部位とは組成の異なる材料が埋め込まれている、請求項１～３の何れか1項に記載の情報処理デバイス。     The third structure layer is
    The material according to any one of claims 1 to 3, wherein a via hole is formed in a region where the first electrode and the second electrode are formed, and a material having a composition different from that of another portion is embedded in the via hole. The information processing device described.
  5. 　前記第３構造層が、
    　　前記入力信号の入力に伴い変形し、
    　前記第２構造層が、
    　　前記第３構造層の変形に伴って、前記第１領域の磁気異方性が変化することにより前記第１領域にて前記スピン波が励起される、請求項１～４のいずれか１項に記載の情報処理デバイス。     The third structure layer is
    Deformed with the input of the input signal,
    The second structural layer comprises:
    The spin wave is excited in the first region by changing the magnetic anisotropy of the first region in accordance with the deformation of the third structure layer. The information processing device described.
  6. 　前記第３構造層が、
    　　前記入力信号の入力に伴い、分極ベクトルが変化し、
    　前記第２構造層が、
    　　前記第３構造層における分極ベクトルの変化に伴って生じる電気磁気効果に起因して磁気異方性が変化することにより前記第１領域にて前記スピン波が励起される、請求項１～４のいずれか１項に記載の情報処理デバイス。     The third structure layer is
    With the input of the input signal, the polarization vector changes,
    The second structural layer comprises:
    The spin wave is excited in the first region by changing magnetic anisotropy due to an electromagnetic effect caused by a change in polarization vector in the third structure layer. The information processing device according to any one of claims.
  7. 　前記ビアホール内に埋め込まれた材料が、
    　　前記入力信号の入力に伴い、スピン偏極電子流を生じ、
    　前記第２構造層が、
    　　前記ビアホール内の材料に生じたスピン偏極電子流に伴って生じる電気磁気効果に起因して磁気異方性が変化することにより前記第１領域にて前記スピン波が励起される、請求項４に記載の情報処理デバイス。     The material embedded in the via hole is
    As the input signal is input, a spin-polarized electron current is generated,
    The second structural layer comprises:
    5. The spin wave is excited in the first region by a change in magnetic anisotropy due to an electromagnetic effect caused by a spin-polarized electron flow generated in the material in the via hole. Information processing device according to.
  8. 　前記ビアホール内に埋め込まれた材料が、
    　　前記入力信号の入力に伴い、トンネル磁気抵抗効果により、スピンの歳差運動を生じ、
    　前記第３構造が、
    　　当該スピンからの漏えい磁場、或いは、当該スピンによるスピン間交換相互作用により磁気異方性が変化することによって、前記第１領域にて前記スピン波が励起される、請求項４に記載の情報処理デバイス。     The material embedded in the via hole is
    Along with the input of the input signal, due to the tunnel magnetoresistance effect, spin precession occurs,
    The third structure is
    5. The information processing according to claim 4, wherein the spin wave is excited in the first region by changing a magnetic anisotropy due to a leakage magnetic field from the spin or an inter-spin exchange interaction by the spin. device.
  9. 　前記第２電極に対して、直流バイアス電流を印加する電流印加手段をさらに有する、請求項８に記載の情報処理デバイス。
     

          The information processing device according to claim 8, further comprising a current applying unit that applies a DC bias current to the second electrode.


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