Magnetic device based on magnetic spin transfer torque

Abstract

The present disclosure relates to magnetic devices such as magnetic transistors and magnetic memories that are regulated by magnetic spin transfer torque. According to one embodiment, a magnetic device based on magnetic spin transfer torque can include a first spin Hall effect layer, a first ferromagnetic insulating layer formed on the first spin Hall effect layer, an anti-ferromagnetic insulating layer formed on the first ferromagnetic insulating layer, a second ferromagnetic insulating layer formed on the anti-ferromagnetic insulating layer, and a second spin Hall effect layer formed on the second ferromagnetic insulating layer.

Description

TECHNICAL FIELD

[0001] The present application relates generally to the field of spintronics, and more particularly, to a magnonic device that utilizes magnon transfer torque to flip the direction of magnetic moment, which can be used as a magnonic transistor or a magnonic memory device, for example. BACKGROUND

[0002] Conventional magnetic devices utilize current to manipulate magnetic moment, such as spin transfer torque (STT) or spin orbit torque (SOT) generated by spin-polarized current to flip the direction of magnetic moment of a magnetic layer. Such devices suffer from some inherent drawbacks, such as current breakdown of magnetic tunnel junction, and current-related issues such as heating and power consumption, etc. SUMMARY

[0003] To address the above issues, the present application proposes a magnonic device that utilizes magnons to manipulate magnetic moment. In the magnonic device, a magnon current can be injected into a ferromagnetic insulating layer using, for example, the spin Hall effect (SHE), which flips the magnetic moment of the ferromagnetic insulating layer through the magnon transfer torque (MTT) effect. On the other hand, the injected magnon current can be detected using the inverse spin Hall effect (ISHE). In the magnonic device, by constructing parallel or anti-parallel magnetic moment structures, the turn-on or turn-off of the magnon current can be controlled.

[0004] According to an embodiment, a magnonic device based on magnon transfer torque (MTT) is provided, comprising: a first spin Hall effect layer; a first ferromagnetic insulating layer formed on the first spin Hall effect layer; an anti-ferromagnetic insulating layer formed on the first ferromagnetic insulating layer; a second ferromagnetic insulating layer formed on the anti-ferromagnetic insulating layer; and a second spin Hall effect layer formed on the second ferromagnetic insulating layer.

[0005] In an embodiment, the second ferromagnetic insulating layer has a fixed in-plane magnetic moment, and the first ferromagnetic insulating layer has a flipable in-plane magnetic moment to be arranged in parallel or anti-parallel with the magnetic moment of the second ferromagnetic insulating layer.

[0006] In an embodiment, the first spin Hall effect layer is configured to receive an in-plane write current and an in-plane read current, the direction of the in-plane write current is substantially perpendicular to, or parallel or anti-parallel to the direction of the magnetic moment of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer, and the direction of the in-plane read current is substantially perpendicular to the direction of the magnetic moment of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer.

[0007] In one embodiment, when the direction of the in-plane write current is substantially parallel or anti-parallel to the magnetization direction of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer, the first spin Hall effect layer is formed of an anti-ferromagnetic material with spin Hall effect to apply a bias magnetic field to the first ferromagnetic insulating layer, the bias magnetic field being substantially perpendicular to the first ferromagnetic insulating layer.

[0008] In one embodiment, when the direction of the in-plane write current is substantially parallel or anti-parallel to the magnetization direction of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer, the magnonic device further comprises a bias magnetic layer formed on the side of the first spin Hall effect layer opposite to the first ferromagnetic insulating layer, the bias magnetic layer applying a bias magnetic field to the first ferromagnetic insulating layer, the bias magnetic field being substantially perpendicular to the first ferromagnetic insulating layer.

[0009] In one embodiment, the magnonic device is used as a magnon transistor or a magnon memory device.

[0010] According to one embodiment, there is provided a method of operating the above magnonic device, comprising: at write, applying an in-plane write current to the first spin Hall effect layer to flip the magnetization of the first ferromagnetic insulating layer to be parallel or anti-parallel to the magnetization of the second ferromagnetic insulating layer; and at read, applying an in-plane read current to the first spin Hall effect layer and detecting whether there is an induced current on the second spin Hall effect layer.

[0011] In one embodiment, the first ferromagnetic insulating layer and the second ferromagnetic insulating layer have in-plane magnetization, the direction of the in-plane write current is substantially perpendicular or parallel or anti-parallel to the magnetization direction of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer, and the direction of the in-plane read current is substantially perpendicular to the magnetization direction of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer.

[0012] In one embodiment, the direction of the induced current is parallel or anti-parallel to the in-plane read current applied to the first spin Hall effect layer.

[0013] In one embodiment, detecting whether there is an induced current on the second spin Hall effect layer comprises: when an induced current is detected on the second spin Hall effect layer, determining that the magnetization of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer is in a parallel state; and when no induced current is detected on the second spin Hall effect layer, determining that the magnetization of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer is in an anti-parallel state.

[0014] The magnonic device of the present application can avoid or reduce the problems of current-related breakdown, heating and power consumption, and the like, and improve the durability and stability of the device, and therefore has a high application prospect.

[0015] The above and other features and advantages of the present application will become more apparent from the following description of exemplary embodiments taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a structural schematic diagram of a magnonic device according to an embodiment of the present application.

[0017] Figure 2A and 2B is Figure 1 is a write operation schematic diagram of the magnonic device shown in

[0018] Figure 3 is Figure 1 is a read operation schematic diagram of the magnonic device shown in

[0019] Figure 4 is a structural schematic diagram of a magnonic device according to another embodiment of the present application. DETAILED DESCRIPTION

[0020] In the following, exemplary embodiments according to the present application will be described in detail with reference to the accompanying drawings. Note that the drawings can not be drawn to scale. Obviously, the described embodiments are only a part of the embodiments of the present application, and the present application is not limited to the exemplary embodiments described herein.

[0021] Figure 1 is a structural schematic diagram of a magnonic device 100 according to an embodiment of the present application. Referring to Figure 1 , the magnonic device 100 can include a first spin Hall effect (SHE) layer 110, a first ferromagnetic insulating layer 120, an anti-ferromagnetic insulating layer 130, a second ferromagnetic insulating layer 140, and a second spin Hall effect (SHE) layer 150, which are sequentially formed on a substrate (not shown).

[0022] As the name implies, the spin Hall effect layer is a layer formed of a material having a spin Hall effect, which has a strong spin-orbit coupling, and thus can generate and accumulate spin current on its surface when an electric current flows therethrough. Examples of the spin Hall effect material include, but are not limited to, metals or alloys such as Pt, Au, Ta, Pd, Ir, W, Bi, Pb, Hf, IrMn, PtMn, AuMn, and the like, and materials such as topological insulators such as Bi2Se3 and Bi2Te3, and the like.

[0023] In Figure 1In the illustrated embodiment, the first spin Hall effect layer 110 can be formed of one or more of the spin Hall effect materials described above. In particular, when the first spin Hall effect layer 110 is formed of an anti-ferromagnetic material having a spin Hall effect, such as IrMn, PtMn, AuMn, it can apply a bias magnetic field to the first ferromagnetic insulating layer 120, such as Figure 2B The illustrated bias magnetic field Hb, which can be substantially perpendicular to the first ferromagnetic insulating layer 120, will be described in further detail below. The thickness of the first spin Hall effect layer 110 can be in a range of, for example, 0.5 nm to 50 nm, preferably in a range of 0.8 nm to 20 nm, and more preferably in a range of 1.0 nm to 10 nm.

[0024] The first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 can each be formed of a ferromagnetic insulating material. Examples of such materials include Fe3O4, garnet-type ferrite (YIG) materials R3Fe5O12, where R is Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu, spinel-type ferrite materials MFe2O4, where M is Mn, Zn, Cu, Ni, Mg, or Co, magnetoplumbite-type ferrite materials AFe12O19, where A is Ba or Sr, and doped compounds thereof. 12 12 19 It will be appreciated that the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 can be formed of the same or different materials, and can have the same or different thicknesses.

[0025] The anti-ferromagnetic insulating layer 130 can be formed of an anti-ferromagnetic insulating material. Examples of such materials include NiO, CoO, and the like. The materials and thicknesses of the first ferromagnetic insulating layer 120, the anti-ferromagnetic insulating layer 130, and the second ferromagnetic insulating layer 140 can be selected as appropriate so that magnonic current (or spin waves) can be conducted from the first spin Hall effect layer 110 to the second spin Hall effect layer 150, as will be described in further detail below.

[0026] The second spin Hall effect layer 150 can also be formed of one or more of the spin Hall effect materials described above. Examples of such materials include the metals or alloys described above, such as Pt, Au, Ta, Pd, Ir, W, Bi, Pb, Hf, IrMn, PtMn, AuMn, and the like, as well as topological insulators such as Bi2Se3and Bi2Te3, and the like. The thickness of the second spin Hall effect layer 150 can be in a range of, for example, 0.5 nm to 50 nm, preferably in a range of 0.8 nm to 20 nm, and more preferably in a range of 1.0 nm to 10 nm. It will be appreciated that the first spin Hall effect layer 110 and the second spin Hall effect layer 150 can be formed of the same or different materials, and can have the same or different thicknesses.​​

[0027] The above refers to Figure 1 the basic structure of the magnonic device 100. The operation principle of the magnonic device 100 will be discussed below in connection with Figure 2A , Figure 2B and Figure 3 . As can be understood from the following description, the magnonic device 100 can be used as, for example, a magnonic transistor or a magnonic memory device.

[0028] Firstly, reference is made to Figure 2A which schematically illustrates a write (or set) operation of the magnonic device 100. As shown in Figure 2A , the first ferromagnetic insulating layer 120 has a flipable in-plane magnetic moment, as indicated by the double-headed dashed arrow, and can thus also be referred to as a free magnetic layer; the second ferromagnetic insulating layer 140 has an in-plane magnetic moment that is fixed during operation, as indicated by the single-headed solid arrow, and can thus also be referred to as a reference magnetic layer. By flipping the magnetic moment of the first ferromagnetic insulating layer 120, the magnetic moments of the first and second ferromagnetic insulating layers 120, 140 can be arranged parallel or anti-parallel to each other. It can be appreciated that, in order to fix the magnetic moment of the second ferromagnetic insulating layer 140, the second ferromagnetic insulating layer 140 can be made to have a large thickness, so as to have a large magnetic moment that is not easily changed by external influences, or the second spin Hall effect layer 150 can be formed of an anti-ferromagnetic material, so as to pin the magnetic moment of the second ferromagnetic insulating layer 140 in a desired direction.

[0029] During the write operation, an in-plane write current I w , as indicated by the hollow arrow in Figure 2A , can be applied to the first spin Hall effect layer 110. The in-plane write current Iwmay be substantially perpendicular to the magnetic moment direction, or the easy axis direction, of the first and second ferromagnetic insulating layers 120, 140. When the write current Iwis applied, a large amount of spin-polarized charges, also referred to as spin current, is generated and accumulated at the surface of the first spin Hall effect layer 110 due to the spin Hall effect. Since the first ferromagnetic insulating layer 120 adjacent to the first spin Hall effect layer 110 is formed of an insulating material, the spin-polarized charges accumulated at the interface between the first spin Hall effect layer 110 and the first ferromagnetic insulating layer 120 cannot diffuse into the first ferromagnetic insulating layer 120. However, the spin-polarized charges can couple with the d-electrons in the first ferromagnetic insulating layer 120 to generate magnons, which can also be referred to as magnons or spin waves, as indicated by the circle with arrow in Figure 2A , and the generated magnons can diffuse from the interface between the first ferromagnetic insulating layer 120 and the first spin Hall effect layer 110 towards the other side of the first ferromagnetic insulating layer 120. The polarization direction of the generated magnons can be determined according to the in-plane write current Iw The direction of the spin Hall effect and the sign of the spin Hall angle of the spin Hall effect material forming the first spin Hall effect layer 110 are determined by the right-hand rule. That is, in Figure 2A In the embodiment shown, an in-plane write current I is applied to the first spin Hall effect layer 110 along the Y-axis (positive or negative) direction. w The spin polarization direction of the generated magnetic particles can be in the X-axis (positive or negative) direction. Magnetic particles generated in the first ferromagnetic insulating layer 120 can exert a magneton transfer torque (MTT) on the magnetic moment of the first ferromagnetic insulating layer 120, which tends to flip the magnetic moment of the first ferromagnetic insulating layer 120 to the direction aligned with the magnetic particle polarization direction. When the density of the in-plane write current Iw applied to the first spin Hall effect layer 110 is sufficiently large to generate a sufficiently strong magnetic particle transfer torque, the magnetic moment of the first ferromagnetic insulating layer 120 can be flipped to the desired direction, i.e., the same direction as the magnetic particle polarization direction. This can be achieved by controlling the in-plane write current Iw. w The direction, such as the positive Y-axis direction or the negative Y-axis direction, controls the direction of magnetic moment reversal of the first ferromagnetic insulating layer 120, so that the magnetic moments of the first ferromagnetic insulating layer 120 and the magnetic moments of the second ferromagnetic insulating layer 140 are arranged parallel or antiparallel to each other, thereby completing the writing operation.

[0030] Figure 2B This demonstrates another writing method. It should be understood that, above... Figure 2A In the writing method shown, the first spin Hall effect layer 110 may or may not apply a bias magnetic field to the first ferromagnetic insulating layer 120. In this case, the in-plane write current Iw, which is substantially perpendicular to the magnetic moment direction of the first ferromagnetic insulating layer 120, can reverse the magnetic moment direction of the first ferromagnetic insulating layer 120. Figure 2B In the illustrated embodiment, the first spin Hall effect layer 110 may be formed of an antiferromagnetic material, and it applies a bias magnetic field Hb to the first ferromagnetic insulating layer 120. b The direction can be substantially perpendicular to the first ferromagnetic insulating layer 120. In Figure 2B In the example, the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 are in the XY plane, and their magnetic moment direction is in the X-axis direction. At this time, the bias magnetic field H b It can be in the Z-axis direction.

[0031] Continue to refer to Figure 2B During the write operation, an in-plane write current I is applied to the first spin Hall effect layer 110. w It can be substantially parallel or antiparallel to the magnetic moment direction, or in other words, the easy magnetization axis direction, of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140. In this case, it is consistent with the above reference... Figure 2AThe principle described is the same; magnons are also excited in the first ferromagnetic insulating layer 120. Their polarization direction can be determined by the right-hand rule as perpendicular to the in-plane magnetic moment direction of the first ferromagnetic insulating layer 120. In the Y-axis direction, for example... Figure 2B The circle with the arrow indicates that, under the combined action of the magneton transfer torque (MTT) generated by the magneton and the bias magnetic field Hb, the magnetic moment of the first ferromagnetic insulating layer 120 can be reversed. This can be controlled by the in-plane write current I. w The direction, such as the positive X-axis direction or the negative X-axis direction, controls the direction of magnetic moment reversal of the first ferromagnetic insulating layer 120, so that the magnetic moments of the first ferromagnetic insulating layer 120 and the magnetic moments of the second ferromagnetic insulating layer 140 are arranged parallel or antiparallel to each other, thereby completing the writing operation.

[0032] The following reference Figure 3 To describe the read (or run) operation. For example... Figure 3 As shown, during reading, an in-plane readout current I is applied to the first spin Hall effect layer 110. r Regarding the previous discussion on write current I... w The principle described is similar, reading the current I. r This will also generate a magnetic current that diffuses from the first ferromagnetic insulating layer 120 to the second ferromagnetic insulating layer 140, but the read current I r The density can be less than the write current I. w The density, thereby reading the current I. r This will not cause the magnetic moment of the first ferromagnetic insulating layer 120 to be reversed. It should be understood that the antiferromagnetic material forming the antiferromagnetic insulating layer 130 is a good conductor of magnetons, so the generated magneton flow can be conducted through the antiferromagnetic insulating layer 130 toward the second ferromagnetic insulating layer 140.

[0033] At this point, it should be noted that, similar to the magnetoresistance effect of spin-polarized current, the parallel and antiparallel magnetic moment alignment of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 also affects the conduction of the magnetic current. Specifically, when the magnetic moments of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 are aligned in parallel, the magnetic current can be smoothly conducted into the second ferromagnetic insulating layer 140, and then reach the interface between the second ferromagnetic insulating layer 140 and the second spin Hall effect layer 150; when the magnetic moments of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 are aligned in antiparallel, the magnetic current conducted through the first ferromagnetic insulating layer 120 and the antiferromagnetic insulating layer 130 will be scattered at the interface between the antiferromagnetic insulating layer 130 and the second ferromagnetic insulating layer 140, and therefore cannot be conducted to the second spin Hall effect layer 150.

[0034] Continue to refer to Figure 3 When reading current I rWhen the generated magnetic flux is conducted to the second spin Hall effect layer 150, an induced current I can be generated in the second spin Hall effect layer 150 through the inverse spin Hall effect (ISHE). ind It is understandable that the induced current I... ind The direction depends on the sign of the spin Hall angle of the materials forming the first spin Hall effect layer 110 and the second spin Hall effect layer 150. If the signs of the spin Hall angles of the materials forming the first spin Hall effect layer 110 and the second spin Hall effect layer 150 are the same, for example, both are positive or negative, then the generated induced current I... ind Direction and reading current I r The directions are opposite; if the spin Hall angles of the materials forming the first spin Hall effect layer 110 and the second spin Hall effect layer 150 are opposite to each other, for example, one is positive and the other is negative, then the generated induced current I ind The direction can be related to the reading current I r They are in the same direction.

[0035] Therefore, when a readout current I is applied to the first spin Hall effect layer 110 r At that time, it is possible to detect whether an induced current I is generated on the second spin Hall effect layer 150. ind If an induced current I is detected ind Then it can be determined that the magnetic moments of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 are aligned in parallel, which can correspond to data "0" or "1"; if no induced current I is detected ind Therefore, it can be determined that the magnetic moments of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 are arranged in antiparallel order, which can correspond to the data "1" or "0". Based on this principle, the magnetic device 100 shown in Figure 2 can be used as a magnetic storage device.

[0036] It should be noted that regardless of whether the in-plane write current Iw is perpendicular, parallel, or antiparallel to the magnetic moments of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140, the read current Ir should be perpendicular to the magnetic moments of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140, so that the parallel and antiparallel configuration of the magnetic moments of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 can control (turn on or off) the transmission of the magnetic subcurrent generated by the read current Ir in the vertical direction (Z-axis direction), as described above.

[0037] Furthermore, based on the above principles, Figure 2A and 2B The illustrated magnetic device 100 can also be used as a magnetic transistor. Specifically, when the magnetic moments of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 are aligned in parallel, a readout (or control) current I is applied to the first spin Hall effect layer 110.r On the second spin Hall effect layer 150, there is no induced (or working) current I ind This corresponds to the on state of the magnetic transistor. When the magnetic moments of the first ferromagnetic insulating layer 120 and the second ferromagnetic insulating layer 140 are in anti-parallel alignment, a read (or control) current I r On the second spin Hall effect layer 150, there is no induced (or working) current I ind This corresponds to the off state of the magnetic transistor. As mentioned before, the on state can be set (or written) by applying a set (or write) current I w The magnetic transistor 100 can be set to either the on state or the off state.

[0038] Figure 4 is a structural schematic diagram of a magnetic sub-device 200 according to another embodiment of the present application. In the magnetic sub-device 200, a bias magnetic layer 102 can be formed on the side of the first spin Hall effect layer 110 opposite to the first ferromagnetic insulating layer 120. The bias magnetic layer 102 can have perpendicular magnetic anisotropy, which applies the aforementioned perpendicular bias magnetic field H b to the first ferromagnetic insulating layer 120 through interlayer coupling or exchange coupling effect. At this time, the material forming the first spin Hall effect layer 110 can not be an anti-ferromagnetic material, but a general non-magnetic spin Hall effect material such as those listed above, because at this time the first spin Hall effect layer 110 can no longer be required to apply the bias magnetic field H b to the first ferromagnetic insulating layer 120. Other aspects of the magnetic sub-device 200 are the same as the magnetic sub-device 100, which will not be repeated here.

[0039] In the present application, by using the magnetic sub-transfer torque (MTT) to flip the magnetic moment of the ferromagnetic insulating layer, the problems of breakdown, heating and power consumption related to the current can be avoided or reduced, and the durability and stability of the device are improved. In addition, by using the spin Hall effect to inject the magnetic sub-current on one side of the insulating structure and using the inverse spin Hall effect to detect the magnetic sub-current on the opposite side, the electrical isolation of the electrical signals on both sides of the insulating structure is achieved, which helps to avoid the mutual influence between the electrical signals. Therefore, the magnetic sub-device of the present application has a high application prospect in magnetic sub-transistors, magnetic sub-memory devices and the like.

[0040] The basic principles of the present application are described above in conjunction with specific embodiments, but it should be pointed out that the advantages, advantages, effects and the like mentioned in the present application are only examples and not limitations, and these advantages, advantages, effects and the like cannot be considered as the must-have of each embodiment of the present application. In addition, the above specific details are only for the purpose of example and for the purpose of understanding, and are not limited to the present application, which must use the above specific details to realize.

[0041] The block diagrams of the devices, apparatuses, equipment, systems referred to in this application are only illustrative examples and are not intended to require or imply that the connections, arrangements, configurations must be as shown in the block diagrams. These devices, apparatuses, equipment, systems can be connected, arranged, configured in any manner as will be appreciated by those skilled in the art. Words such as "including," "containing," "comprising," and the like are to be construed in an inclusive fashion, indicating open-ended groups and that "consisting of will be perceived as specifying the noted components or steps and further alternative embodiments are useful while yet being encompassed by such definitions. The words "or" and "and" as used herein are to be interpreted as the word "and / or" unless context indicates otherwise. The word "comprising" as used herein is to be construed as "including but not limited to."

[0042] It is also important to note that the devices, apparatuses, and methods of the present application can be embodied in a variety of forms without departing from the spirit or essential characteristics thereof. These devices, apparatuses, and methods can be implemented in software, hardware, or a combination thereof. Furthermore, wherever possible, any aspects or embodiments of the present application can be implemented by using any of the following technologies: software, hardware, firmware, or fixed logic circuitry; or any combination thereof. For example, a general purpose processor, a controller, or other digital circuitry can be used when software modules or firmware modules are implemented as processing tasks performed by a microprocessor or other digital signal processing (DSP) device. A general purpose processor can be a microprocessor, but in the alternative, a controller or other digital circuitry can be used. One of ordinary skill in the art will further appreciate that the mechanisms of the present application can be implemented by varying the software modules, firmware modules, or hardware modules. In addition, the described

[0043] The above description of disclosed aspects is given for illustrative purposes only and is not intended to limit the scope of the application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0044] The above description has been presented for the purpose of illustration and description. Furthermore, the description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although various example aspects and embodiments have been discussed above, those of ordinary skill in the art will readily appreciate that some variations, modifications, changes, additions and sub-combinations of the aspects discussed above can be made without departing from the scope of the application.

Claims

1. A magnonic device based on Magnon Transfer Torque (MTT) comprising: a first spin Hall effect layer; a first ferromagnetic insulating layer formed on the first spin Hall effect layer; an anti-ferromagnetic insulating layer formed on the first ferromagnetic insulating layer; a second ferromagnetic insulating layer formed on the anti-ferromagnetic insulating layer; and a second spin Hall effect layer formed on the second ferromagnetic insulating layer, when writing, applying an in-plane write current to the first spin Hall effect layer to flip the magnetic moment of the first ferromagnetic insulating layer to be parallel or anti-parallel to the magnetic moment of the second ferromagnetic insulating layer; and when reading, applying an in-plane read current to the first spin Hall effect layer and detecting whether there is an induced current on the second spin Hall effect layer. The second ferromagnetic insulating layer has a fixed in-plane magnetic moment, and the first ferromagnetic insulating layer has a flipable in-plane magnetic moment to be arranged parallel or anti-parallel to the magnetic moment of the second ferromagnetic insulating layer. The first spin Hall effect layer is configured to receive the in-plane write current and the in-plane read current, the direction of the in-plane write current is substantially perpendicular to or parallel or anti-parallel to the direction of the magnetic moment of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer, and the direction of the in-plane read current is substantially perpendicular to the direction of the magnetic moment of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer.

2. The magnonic device of claim 1, wherein, When the direction of the in-plane write current is substantially parallel or anti-parallel to the direction of the magnetic moment of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer, the first spin Hall effect layer is formed of an anti-ferromagnetic material having a spin Hall effect to apply a bias magnetic field to the first ferromagnetic insulating layer, the bias magnetic field being substantially perpendicular to the first ferromagnetic insulating layer.

3. The magnonic device of claim 1, wherein, When the direction of the in-plane write current is substantially parallel or anti-parallel to the direction of the magnetic moment of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer, the magnonic device further comprises:

4. The magnonic device of claim 3, wherein, a bias magnetic layer formed on the side of the first spin Hall effect layer opposite to the first ferromagnetic insulating layer, the bias magnetic layer applying a bias magnetic field to the first ferromagnetic insulating layer, the bias magnetic field being substantially perpendicular to the first ferromagnetic insulating layer.

5. The magnonic device of claim 3, wherein, The magnonic device is used as a magnonic transistor or a magnonic memory device. 7.A method of operating the magnonic device of any one of claims 1-6, comprising:

6. The magnonic device of any one of claims 1-5, wherein, when writing, applying an in-plane write current to the first spin Hall effect layer to flip the magnetic moment of the first ferromagnetic insulating layer to be parallel or anti-parallel to the magnetic moment of the second ferromagnetic insulating layer; and when reading, applying an in-plane read current to the first spin Hall effect layer and detecting whether there is an induced current on the second spin Hall effect layer. The first ferromagnetic insulating layer and the second ferromagnetic insulating layer have in-plane magnetic moments, the direction of the in-plane write current is substantially perpendicular or parallel or anti-parallel to the direction of the magnetic moment of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer, and the direction of the in-plane read current is substantially perpendicular to the direction of the magnetic moment of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer. ​ ​ 8. The method of claim 7, wherein, ​ 9. The method of claim 7, wherein, The direction of the induced current is parallel or anti-parallel to an in-plane read current applied to the first spin Hall effect layer.

10. The method of claim 7, wherein, Detecting whether an induced current is present on the second spin Hall effect layer comprises: When an induced current is detected on the second spin Hall effect layer, then it is determined that the magnetic moments of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer are in a parallel state; and When no induced current is detected on the second spin Hall effect layer, then it is determined that the magnetic moments of the first ferromagnetic insulating layer and the second ferromagnetic insulating layer are in an anti-parallel state.

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