Three-dimensional spin hall nano-oscillator series-parallel array and preparation method

Abstract

The application discloses a three-dimensional spin Hall nano oscillator series-parallel array and a preparation method, wherein the array comprises a plurality of spin Hall nano microwave oscillator units of double-layer and / or three-layer film structures; the plurality of units are arranged in stacks to form a three-dimensional spin Hall nano oscillator series-parallel array; current passes through the left and right electrodes into the oscillator, is converted into a spin current in a strong spin-orbital coupling layer, and acts on a ferromagnetic layer magnetic moment; high-frequency precession of the magnetic moment causes a periodical change of the device resistance through a magnetoresistance effect; under the assistance of a spontaneous exchange bias field generated by exchange coupling effect, a microwave signal is output. The application uses an exchange bias field generated by exchange coupling effect between an anti-ferromagnetic layer and a ferromagnetic layer to replace an external magnetic field, reduces complexity of application, and on the other hand, adopts a three-dimensional spin Hall nano oscillator series-parallel array method to greatly improve output signal power, and can be widely applied to the fields of information communication and radio frequency technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of information communication and radio frequency technology, and particularly relates to a three-dimensional spin Hall nano-oscillator series-parallel array and a preparation method. BACKGROUND

[0002] The spin nano-oscillator is a new type of nano microwave oscillator based on the magnetoresistance effect and the spin torque effect, has the advantages of easy integration, small size, low power consumption, wide frequency modulation range, etc., is one of the smallest microwave oscillators developed at present, and can be applied to the fields of microwave communication, magnetic sensing and artificial intelligence. The spin Hall nano-oscillator (SHNO) utilizes the spin-orbit torque effect, passes a current through a strong spin-orbit coupling layer, generates a spin-orbit torque to drive the magnetic moment in the adjacent magnetic film to precess at a high frequency, detects and outputs a microwave signal through the anisotropic magnetoresistance effect (AMR), can realize a fully electrically controlled coherent spin wave and microwave signal emission at a micro / nano scale, and has a wide application prospect in information storage, processing and communication. An external current and magnetic field are effective ways to tune the output frequency and power of the spin nano-oscillator. However, the stable self-oscillation of the spin nano-oscillator requires the condition of an external magnetic field, which limits its application.

[0003] The spin transfer nano-oscillator (STNO) is composed of a reference layer, a free layer and a barrier layer separating the two layers. The current flows from the reference layer end, and the spin-polarized current carrying the magnetic moment direction of the reference layer causes the magnetic moment of the free layer to precess uniformly. The microwave signal is detected and output through the giant magnetoresistance effect (GMR) or the tunnel magnetoresistance effect (TMR). Compared with the STNO, the output power of the SHNO is smaller, because the signal detected by the AMR is weaker than the signal detected by the GMR / TMR. SUMMARY

[0004] To at least partially solve one of the technical problems existing in the prior art, the purpose of the present application is to provide a three-dimensional spin Hall nano-oscillator series-parallel array based on exchange bias and a preparation method.

[0005] The technical scheme adopted by the present application is as follows:

[0006] A three-dimensional spin Hall nano-oscillator series-parallel array, comprising a plurality of spin Hall nano microwave oscillator units of a double-layer thin film structure and / or spin Hall nano microwave oscillator units of a three-layer thin film structure; the plurality of spin Hall nano microwave oscillator units are stacked and arranged in a predetermined manner to form a three-dimensional spin Hall nano-oscillator series-parallel array.

[0007] The spin Hall nano microwave oscillator unit of the double-layer thin film structure is composed of an antiferromagnetic layer, a ferromagnetic layer above the antiferromagnetic layer and left and right side electrodes.

[0008] The spin Hall nano microwave oscillator unit of the three-layer thin film structure is composed of an anti-ferromagnetic layer, a ferromagnetic layer above the anti-ferromagnetic layer, a strong spin-orbit coupling layer above the ferromagnetic layer, and left and right side electrodes;

[0009] Wherein, the current passes through the left and right electrodes into the oscillator, is converted into a spin current in the strong spin-orbit coupling layer, and acts on the magnetic moment of the ferromagnetic layer; the high-frequency precession of the magnetic moment causes the periodical change of the resistance of the device through the magnetoresistance effect; and the spontaneous exchange bias field generated by the exchange coupling between the anti-ferromagnetic layer and the ferromagnetic layer provides assistance, and finally outputs the microwave signal.

[0010] Further, there is an exchange bias effect at the interface between the anti-ferromagnetic layer and the ferromagnetic layer;

[0011] When the current flows through the oscillator, the anti-ferromagnetic layer generates an in-plane or out-of-plane exchange bias field to the ferromagnetic layer under the influence of the exchange coupling effect, and the electrically controlled exchange bias field replaces the required additional external magnetic field, realizing field-free oscillation, so that the application of the spin nano oscillator is more convenient.

[0012] Further, in the spin Hall nano microwave oscillator unit of the double-layer thin film structure, the anti-ferromagnetic layer is an anti-ferromagnetic metal thin film; the current flowing through the anti-ferromagnetic layer generates a spin-orbit torque (SOT) to the ferromagnetic layer, and the exchange coupling effect between the anti-ferromagnetic layer AFM and the ferromagnetic layer FM generates a corresponding exchange bias field; under the synergistic action of the internal auxiliary field of the oscillator and the SOT driving the precession of the magnetic moment of the ferromagnetic layer, the oscillator provides a microwave signal.

[0013] In the spin Hall nano microwave oscillator unit of the three-layer thin film structure, the anti-ferromagnetic layer is an anti-ferromagnetic insulating thin film; the current flowing through the strong spin-orbit coupling layer generates a SOT to the ferromagnetic layer, and the exchange coupling effect between the anti-ferromagnetic layer AFM and the ferromagnetic layer FM generates a corresponding exchange bias field; under the synergistic action of the internal auxiliary field of the oscillator and the SOT driving the precession of the magnetic moment of the ferromagnetic layer, the oscillator provides a microwave signal.

[0014] Further, the material of the anti-ferromagnetic metal thin film is MnN, CrN, FeMn, NiMn, IrMn, PtMn, PtPdMn, CrMn, or CrAl;

[0015] The material of the anti-ferromagnetic insulating thin film is NiO, CoO, Ni x Co 1-x O, FeO, Fe2O3, Fe3O4, Cr2O3, FeF2, MnF2, or BiFeO3.

[0016] Further, the spin Hall nanometer microwave oscillator unit further comprises a seed layer and a cover layer; the seed layer is arranged on the side of the antiferromagnetic layer opposite to the ferromagnetic layer, and the cover layer is arranged on the top layer of the oscillator.

[0017] Further, the spin Hall nanometer microwave oscillator unit further comprises a barrier layer and a fixed layer.

[0018] The ferromagnetic layer serves as a free layer, and together with the additionally deposited barrier layer and fixed layer, forms a magnetic tunnel junction; the magnetic tunnel junction is stacked on the bottom antiferromagnetic layer.

[0019] The current passing through the antiferromagnetic layer is converted into a spin current and acts on the magnetic moment of the free layer; the high-frequency precession of the magnetic moment causes the periodic change of the resistance of the device, and the current passing through the fixed layer is detected to read the final output microwave signal by using the TMR effect.

[0020] Further, when the magnetic moment of the free layer is opposite to the magnetic moment of the fixed layer, it shows a high resistance state; when the magnetic moment of the free layer is the same as the magnetic moment of the fixed layer, it shows a low resistance state.

[0021] Further, the spin Hall nanometer microwave oscillator unit further comprises a pinning layer, which is arranged on any side of the fixed layer.

[0022] The pinning layer is arranged above the fixed layer as an interlayer of the fixed layer and the cover layer; or,

[0023] The pinning layer is arranged below the fixed layer as an interlayer of the fixed layer and the barrier layer.

[0024] The magnetization direction of the fixed layer is kept unchanged by pinning.

[0025] Further, the material of the strong spin-orbit coupling layer is a non-magnetic heavy metal, an alloy material, an antiferromagnetic metal or a topological insulator.

[0026] The material of the ferromagnetic layer is a ferromagnetic metal material.

[0027] Another technical solution adopted by the present application is:

[0028] A preparation method for preparing a three-dimensional spin Hall nanometer oscillator series-parallel array as described above, comprising the following steps:

[0029] Depositing a thin film of the spin Hall nanometer microwave oscillator unit on a substrate, and preparing spin Hall nanometer microwave oscillator units of the same size and shape through photolithography and etching;

[0030] Growth of insulating layer and conductive layer between adjacent spin Hall nanometer microwave oscillator units, photoetching and etching of each stacked thin layer in three-dimensional direction and electrodes of adjacent spin Hall nanometer microwave oscillator unit stacks in sequence;

[0031] Covering the whole top of the three-dimensional spin Hall nanometer oscillator series-parallel array with an insulating layer and a metal layer through deposition, photoetching, etching and other processes;

[0032] Preparation of a full-electrically-controlled three-dimensional spin Hall nanometer microwave oscillator series-parallel array based on exchange bias.

[0033] The beneficial effects of the present application are: the present application uses the exchange bias field generated by the exchange coupling effect of the antiferromagnetic layer and the ferromagnetic layer to replace the external magnetic field, reducing the complexity of application. The structure of the present application can maximize the use of space, combining the spin-orbit torque effect, magnetoresistance effect and exchange bias effect, and can realize oscillation without applying any external magnetic field. At the same time, the SHNO is arranged under the 3D array, and the number of spin Hall nanometer oscillators can be integrated in large quantities, and the synchronization or coupling effect between them overcomes the shortcomings of low output signal power and wide line width of the current spin nanometer oscillator, and the structure is simple, which has a positive effect on further promoting the application and development of spin nanometer oscillator. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following introduces the drawings of the related technical solutions in the embodiments of the present application or the prior art. It should be understood that the drawings in the following introduction are only for the convenience of clearly describing part of the embodiments in the technical solutions of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0035] Figure 1 is a schematic diagram of a spin Hall nanometer microwave oscillator unit with a double-layer thin film structure in the embodiments of the present application;

[0036] Figure 2 is a schematic diagram of a spin Hall nanometer microwave oscillator unit with a three-layer thin film structure in the embodiments of the present application;

[0037] Figure 3 is a three-dimensional schematic diagram of a nanowire type spin Hall nanometer microwave oscillator with a double-layer thin film structure in the embodiments of the present application;

[0038] Figure 4 is a three-dimensional schematic diagram of a nanowire type spin Hall nanometer microwave oscillator with a three-layer thin film structure in the embodiments of the present application;

[0039] Figure 5is a three-dimensional schematic diagram of a one-dimensional nanowire type spin Hall nanometer microwave oscillator horizontal series array in an embodiment of the present application;

[0040] Figure 6 is a three-dimensional schematic diagram of a two-dimensional nanowire type spin Hall nanometer microwave oscillator series-parallel array in an embodiment of the present application;

[0041] Figure 7 is a three-dimensional schematic diagram of a two-dimensional nanowire type spin Hall nanometer microwave oscillator horizontal parallel array in an embodiment of the present application;

[0042] Figure 8 is a three-dimensional schematic diagram of a three-dimensional parallel array of a full-electric-controlled nanowire type spin Hall nanometer microwave oscillator based on exchange bias in an embodiment of the present application;

[0043] Figure 9 is a three-dimensional schematic diagram of a two-dimensional nanowire type spin Hall nanometer microwave oscillator vertical series array in an embodiment of the present application;

[0044] Figure 10 is a three-dimensional schematic diagram of a two-dimensional nanowire type spin Hall nanometer microwave oscillator vertical parallel array in an embodiment of the present application;

[0045] Figure 11 is a three-dimensional schematic diagram of a three-dimensional series-parallel array of a full-electric-controlled nanowire type spin Hall nanometer microwave oscillator based on exchange bias in an embodiment of the present application;

[0046] Figure 12 is a top view of a three-dimensional series-parallel array of a full-electric-controlled nanowire type spin Hall nanometer microwave oscillator based on exchange bias in an embodiment of the present application;

[0047] Figure 13 is a three-dimensional schematic diagram of a three-dimensional series array of a full-electric-controlled nanowire type spin Hall nanometer microwave oscillator based on exchange bias in an embodiment of the present application;

[0048] Figure 14 is a three-dimensional schematic diagram of another three-dimensional series-parallel array of a full-electric-controlled nanowire type spin Hall nanometer microwave oscillator based on exchange bias in an embodiment of the present application;

[0049] Figure 15 is a top view of another three-dimensional series-parallel array of a full-electric-controlled nanowire type spin Hall nanometer microwave oscillator based on exchange bias in an embodiment of the present application;

[0050] Figure 16 is a circuit connection schematic diagram of a three-dimensional series-parallel array of a full-electric-controlled spin Hall nanometer microwave oscillator based on exchange bias in an embodiment of the present application;

[0051] Figure 17is a schematic diagram of a series-parallel array of all-electric control three-dimensional spin Hall nanomagnetic microwave oscillator based on exchange bias m(t) in an embodiment of the present application;

[0052] Figure 18 is a schematic diagram of a series-parallel array of all-electric control three-dimensional spin Hall nanomagnetic microwave oscillator based on exchange bias FFT in an embodiment of the present application. DETAILED DESCRIPTION

[0053] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. For the step numbers in the following embodiments, they are only set for the convenience of explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0054] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as a limitation of the present application, indicating or implying that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation.

[0055] In the description of the present application, the meaning of several is one or more, and the meaning of multiple is two or more than two, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of indicated technical features. In addition, "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent: A exists alone, A and B exist together, and B exists alone. The character " / " generally represents that the front and rear associated objects have an "or" relationship.

[0056] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0057] Term explanation:

[0058] SHNO: a double-layer or three-layer structure spin Hall nanomagnetic microwave oscillator unit.

[0059] SOT: spin orbit torque.

[0060] FM: ferromagnetic layer.

[0061] AFM: antiferromagnetic layer.

[0062] GMR: giant magnetoresistance.

[0063] TMR: tunneling magnetoresistance.

[0064] AMR: anisotropic magnetoresistance.

[0065] Due to the advantages of simple structure, easy preparation, convenient electrical access and the like, the SHNO structure has broad application prospects. Generally, the power of a single spin Hall nano oscillator is small, and the line width is large. In order to improve this situation, compared with the one-dimensional and two-dimensional SHNOs, the three-dimensional series-parallel array method can greatly improve the output signal power. The spin nano oscillator has a nonlinear characteristic, and two or more oscillators are easy to synchronize or couple, thereby enhancing the microwave signal. The nanowire type oscillator structure can effectively suppress the dephasing phenomenon, and is conducive to the coherent self-oscillation of the entire nanowire. Under the condition of synchronization of the frequency and phase of adjacent SHNOs, the oscillation intensity is uniformly distributed in the entire oscillation region. Based on the nanowire type structure, the one-dimensional nanowire type SHNO series long chain, the two-dimensional nanowire type horizontal and vertical series-parallel array, and the three-dimensional series-parallel array are included. The multi-dimensional oscillator array can utilize the nonlinearity of itself, improve the coherence and output power of the whole system under the mutual locking behavior, and reduce the line width. On the other hand, the SHNO usually needs a strong magnetic field to realize a large frequency range, and a complex electromagnet or permanent magnet is needed to provide an external magnetic field, which greatly increases the design complexity and the size of the device. The application proposes a scheme for providing an equivalent external magnetic field by using the magnetic exchange bias effect, which can realize a high-frequency spin Hall nano oscillator without an external magnetic field. This three-dimensional field-free oscillation method can integrate more oscillators in a smaller area without the need for external magnetic field equipment, thereby realizing higher output power. Through the antiferromagnetic exchange bias effect, an in-plane or out-of-plane bias field is directly or indirectly formed on the ferromagnetic layer to replace the auxiliary external magnetic field. On the basis of one-dimensional and two-dimensional arrays, a three-dimensional series-parallel array is constructed, and finally a scheme of a three-dimensional series-parallel spin Hall nano oscillator array without a magnetic field and fully electrically controlled is realized, so as to solve the problems of dependence on an external magnetic field for outputting a microwave signal and small output microwave signal power, and make the spin nano oscillator more simple and practical.

[0066] Overall, the application proposes a new three-dimensional series-parallel spin Hall nano oscillator array realized by exchange bias effect and spin-orbit torque effect. First, each SHNO unit in the vertical direction is deposited and etched into a square column structure with the same area. The shape is not limited and can be an elliptical column or a rectangular column, etc. According to different situations such as electrical access and three-dimensional series-parallel array stacking mode, an insulating layer and an electrode with a specific size and shape are deposited and photolithographed. The number of stacked SHNOs is not limited. Due to the spin-orbit coupling effect, the current flowing through the SHNO transfers the spin angular momentum to the ferromagnetic layer. With the assistance of the in-plane or out-of-plane exchange bias field, the stable oscillation of the magnetic moment in the ferromagnetic layer is promoted, and the frequency and mode of the oscillation are controlled by the full electrical method. The application generates an exchange bias field through the exchange coupling effect between the antiferromagnetic layer and the ferromagnetic layer, realizes the full-electrically-controlled spin nano oscillator without the assistance of an external magnetic field, and reduces the complexity of the structure. At the same time, the three-dimensional oscillator series-parallel array is synchronized or coupled to output higher intensity microwave signal power.

[0067] The embodiment provides a three-dimensional series-parallel spin Hall nano oscillator array based on exchange bias without magnetic field and full electrical control, which includes a double-layer thin film structure spin Hall nano microwave oscillator unit composed of an antiferromagnetic layer 101, a ferromagnetic layer 102 above the antiferromagnetic layer 101, and left and right side electrodes 103, as shown in Figure 1 The embodiment also includes a three-layer thin film structure spin Hall nano microwave oscillator unit composed of an antiferromagnetic layer 101, a ferromagnetic layer 102 above the antiferromagnetic layer 101, a strong spin-orbit coupling layer 104 above the ferromagnetic layer 102, and left and right side electrodes 103, as shown in Figure 2 Based on the two kinds of SHNO units, the number of stacked SHNOs and the series-parallel connection mode are not limited, and finally the required spin Hall oscillator 3D series-parallel array is realized.

[0068] In the embodiment, the current passes through the left and right electrodes into the oscillator, is converted into a spin current in the strong spin-orbit coupling layer, and acts on the magnetic moment of the ferromagnetic layer. The high-frequency precession of the magnetic moment causes the periodic change of the device resistance through the magnetoresistance effect. With the assistance of the spontaneous exchange bias field generated by the exchange coupling effect between the antiferromagnetic layer and the ferromagnetic layer, the microwave signal is finally output.

[0069] There is exchange bias effect at the interface between the antiferromagnetic layer and the ferromagnetic layer. When current flows through the oscillator, the antiferromagnetic layer generates an in-plane or out-of-plane exchange bias field to the ferromagnetic layer under the influence of the exchange coupling effect, and the electrically controlled exchange bias field replaces the required additional external magnetic field, realizing field-free oscillation, making the application of spin nanometer oscillator more convenient. When preparing, by controlling the annealing temperature, the cooling field size, and increasing the insertion layer, the ferromagnetic layer is affected by the exchange bias effect of the antiferromagnetic layer, and the size of the exchange bias field can be controlled.

[0070] As an optional implementation, the antiferromagnetic layer includes but is not limited to antiferromagnetic insulating film and antiferromagnetic metal film.

[0071] In some embodiments, the antiferromagnetic layer is an antiferromagnetic metal film. The material of the antiferromagnetic metal film includes but is not limited to MnN, CrN, FeMn, NiMn, IrMn, PtMn, PtPdMn, CrMn, and CrAl.

[0072] When the antiferromagnetic layer is an antiferromagnetic metal film, the following is used Figure 1 The double-layer structure oscillator unit includes an antiferromagnetic layer 101, a ferromagnetic layer 102 above the antiferromagnetic layer, and electrodes 103 on the left and right sides for easy electrical access. Current flowing through the antiferromagnetic layer 101 generates spin orbit torque SOT to the ferromagnetic layer 102, and the exchange coupling effect between the antiferromagnetic layer AFM and the ferromagnetic layer FM generates a corresponding exchange bias field. Under the synergistic effect of the auxiliary field in the oscillator and the SOT driving FM layer magnetic moment precession, the oscillator provides a microwave signal.

[0073] In some embodiments, the antiferromagnetic layer is an antiferromagnetic insulating film. The material of the antiferromagnetic insulating film includes but is not limited to NiO, CoO, Ni x Co 1-x O, FeO, Fe2O3, Fe3O4, Cr2O3, FeF2, Mn F2, and BiFeO3.

[0074] When the antiferromagnetic layer is an antiferromagnetic insulating film, the following is used Figure 2 The three-layer structure oscillator unit includes an antiferromagnetic layer 101, a ferromagnetic layer 102 above the antiferromagnetic layer, a strong spin orbit coupling layer 104 above the ferromagnetic layer, and electrodes 103 on the left and right sides for easy electrical access. Current flowing through the strong spin orbit coupling layer 104 generates SOT to the ferromagnetic layer 102, and the exchange coupling effect between the AFM and the FM generates a corresponding exchange bias field. Under the synergistic effect of the auxiliary field in the oscillator and the SOT driving FM layer magnetic moment precession, the oscillator provides a microwave signal.

[0075] As an optional implementation, the material of the strong spin-orbital coupling layer includes but is not limited to non-magnetic heavy metal, alloy material, anti-ferromagnetic metal, topological insulator. The non-magnetic heavy metal includes but is not limited to Pt, Ta, W, Hf. The alloy material includes but is not limited to CuBi, CuPt, CuAu. The topological insulator includes but is not limited to Bi2Se3, (Bi 0.5 Sb 0.5 )2Te3, Bi x Se 1-x , Bi 0.9 Sb 0.1 .

[0076] As an optional implementation, the material of the ferromagnetic layer is a ferromagnetic metal material. The ferromagnetic metal material includes but is not limited to Fe, Co, Ni, FeNi, CoFe, CoFeB, Co2FeAl, CoMnSi, Fe3Si, YIG, GdFeCo, GdCo5, DyCo5, TbFe2, BaFe 12 O 19 .

[0077] As an optional implementation, the spin nanometer oscillator can further include a seed layer and a cover layer, the seed layer is arranged on the side of the anti-ferromagnetic layer opposite to the ferromagnetic layer, and the cover layer is arranged on the top layer of the oscillator.

[0078] Specifically, in order to improve the efficiency of the detection signal, the giant magnetoresistance effect or the tunneling magnetoresistance effect can be applied instead of or in cooperation with the anisotropic magnetoresistance effect, so as to greatly improve the strength of the output microwave signal.

[0079] As an optional embodiment, the spin nano-oscillator further comprises a magnetic tunnel junction composed of two ferromagnetic layers separated by a barrier layer, and the magnetic tunnel junction is stacked on the bottom anti-ferromagnetic layer. Among them, the two ferromagnetic layers are a fixed layer and a free layer combined directly with the anti-ferromagnetic layer, respectively. The current passing through the anti-ferromagnetic layer is converted into a spin current and acts on the magnetic moment of the free layer. The high-frequency precession of the magnetic moment causes the periodic change of the device resistance. The current passing through the fixed layer is detected, and the final output microwave signal is read by using the TMR effect. The spin nano-oscillator is three-terminal current passing, which separates the read and write channels, reduces the spin-orbit torque current that causes the ferromagnetic layer magnetic moment to oscillate, enhances the read oscillation signal due to the TMR effect, and improves the stability and reliability of the work. Further, when the magnetic moment of the free layer is opposite to the magnetic moment of the fixed layer, it shows a high resistance state; when the magnetic moment of the free layer is the same as the magnetic moment of the fixed layer, it shows a low resistance state. Further, the spin nano-oscillator can further comprise a pinning layer, which is arranged on either side of the fixed layer, i.e. above the fixed layer as an interlayer between the fixed layer and the capping layer, or below the fixed layer as an interlayer between the fixed layer and the barrier layer. The magnetization direction of the fixed layer is kept unchanged by pinning.

[0080] In some embodiments, the material of the barrier layer is an insulating material, and the pinning layer, seed layer, and capping layer are metal materials. The metal material includes but is not limited to Pt, Ta, or W. The insulating material includes but is not limited to MgO or Al2O3.

[0081] As an optional embodiment, the three-dimensional spin Hall nano-oscillator array based on exchange bias and fully electrically controlled without magnetic field is grown on a substrate, and the substrate material includes but is not limited to sapphire, SiC.

[0082] As an optional embodiment, the working principle of detecting the output periodic signal includes but is not limited to anisotropic magnetoresistance effect, giant magnetoresistance effect, and tunneling magnetoresistance effect.

[0083] As an optional embodiment, the spin-orbit torque current includes but is not limited to unidirectional or multidirectional current, single or multiple current, and spin accumulation caused by the spin-orbit torque current flowing through a strong spin-orbit coupling layer, which induces the precession of the magnetic moment.

[0084] The three-dimensional spin Hall nano-oscillator array is explained in detail below in combination with the drawings and specific embodiments.

[0085] In Figure 3 Double-layer and Figure 4Based on the three-layer thin film structure of the nanowire type spin Hall oscillator unit, one-dimensional, two-dimensional and three-dimensional series-parallel oscillator array arrangement is implemented, which further improves the output signal power in multiple dimensions. Combined with the exchange coupling effect between antiferromagnetic / ferromagnetic, it is convenient to realize the final field-free all-electric three-dimensional series-parallel spin Hall nanometer oscillator array.

[0086] Reference Figure 5 Taking a three-dimensional schematic diagram of a one-dimensional nanowire type spin Hall nanometer microwave oscillator horizontal series array as an example, two nanowire type SHNO units are connected in series in the horizontal direction, and the current flows in from one side of the electrode and flows out from the other side of the electrode. The number of series SHNOs is not limited, and the direction is not limited. Reference Figure 6 Taking a three-dimensional schematic diagram of a two-dimensional nanowire type spin Hall nanometer microwave oscillator series-parallel array as an example, based on the one-dimensional nanowire type spin Hall nanometer microwave oscillator horizontal series array, the SHNO units are stacked in the vertical direction to realize the parallel structure, and the number of stacked SHNOs is not limited. When the SHNO is a two-layer thin film structure of the nanowire type spin Hall nanometer microwave oscillator, an insulating layer needs to be added between adjacent SHNO units; when the SHNO is a three-layer thin film structure, an insulating layer can be added between adjacent SHNO units. The current flows in from one side of the electrode and flows out from the other side of the electrode. The number of series SHNOs in the horizontal direction is not limited, and the direction is not limited.

[0087] Reference Figure 7 Taking a three-dimensional schematic diagram of a two-dimensional nanowire type spin Hall nanometer microwave oscillator horizontal parallel array as an example, the SHNOs are arranged in parallel in the horizontal direction to realize the parallel structure, and an insulating layer can be added between adjacent SHNOs. The number of parallel SHNOs is not limited. The current flows in from one side of the electrode and flows out from the other side of the electrode. Reference Figure 8 Taking a three-dimensional schematic diagram of a two-dimensional nanowire type spin Hall nanometer microwave oscillator horizontal parallel array as an example, the SHNOs are arranged in parallel in the horizontal direction to realize the parallel structure, and an insulating layer can be added between adjacent SHNOs. The number of parallel SHNOs is not limited. The current flows in from one side of the electrode and flows out from the other side of the electrode. Reference

[0088] Reference Figure 9 Taking a three-dimensional schematic diagram of a two-dimensional nanowire type spin Hall nanometer microwave oscillator vertical series array as an example, two SHNO units are connected in series in the vertical direction by an insulating layer 105 to isolate the current, and the current flows in from the right electrode of one of the SHNOs, flows to the other SHNO stacked vertically through the left electrode of the SHNO, and then flows out from the right electrode of the SHNO. The current direction can be adjusted. Reference Figure 10Take a three-dimensional schematic diagram of a two-dimensional nanowire type spin Hall nano microwave oscillator vertical parallel array as an example, two SHNO units realize parallel in the vertical direction, and the insertion of the insulating layer is consistent with the previous description. The current flows in from one side of the electrode and out from the other side of the electrode.

[0089] Reference Figure 11 , Figure 12 Take a three-dimensional schematic diagram and a top view of a full-electric control nanowire type spin Hall nano microwave oscillator three-dimensional series-parallel array based on exchange bias as an example, multiple SHNO units realize series-parallel in the horizontal and vertical directions, the number of SHNO units is not limited, the direction of series-parallel is not limited, and the array structure is not limited. The insertion of the insulating layer is consistent with the previous description. The current flows in from one side of the electrode and out from the other side of the electrode.

[0090] Reference Figure 13 Take a three-dimensional schematic diagram of a full-electric control nanowire type spin Hall nano microwave oscillator three-dimensional series array based on exchange bias as an example, two two-dimensional SHNO arrays realize series in the vertical direction by isolating the current through the insulating layer, the current flows in from one side of the electrode of the first SHNO unit at the bottom or top of the series SHNO chain, flows to the other side of the electrode of the last SHNO unit at the bottom or top of the series SHNO chain through the series SHNO chain, and flows out from the last SHNO unit at the top or bottom of the series SHNO chain. The insulating layer needs to be inserted between the vertically adjacent electrodes to isolate the current, and the insertion of the insulating layer between the vertically adjacent SHNO layers is consistent with the previous description.

[0091] Reference Figure 14 , Figure 15 Take a three-dimensional schematic diagram and a top view of another full-electric control nanowire type spin Hall nano microwave oscillator three-dimensional series-parallel array based on exchange bias as an example, on the basis of a two-dimensional nanowire type spin Hall nano microwave oscillator horizontal series array, vertical stacking is performed, and two two-dimensional SHNO arrays realize parallel in the vertical direction, realizing another implementation structure of three-dimensional SHNO series-parallel. The insertion of the insulating layer is consistent with the previous description. The current flows in from one side of the electrode and out from the other side of the electrode. Figure 8 , Figure 11 , Figure 13 , Figure 14 Only part of the implementation structure of the full-electric control nanowire type SHNO three-dimensional series-parallel array based on exchange bias, different three-dimensional series-parallel can be realized by changing the specific implementation structure, including but not limited to the number of vertically stacked SHNO layers, the number of SHNO units, the current application direction, and the local / overall series-parallel mode.

[0092] The embodiment also provides a preparation method flow of a full-electric control three-dimensional spin Hall nano microwave oscillator series-parallel array based on exchange bias, including the following steps:

[0093] Step 1, depositing SHNO basic unit thin film on the substrate, preparing SHNO units with the same size and shape by photolithography and etching;

[0094] Step 2, growing insulating layer and conductive layer between adjacent SHNOs, sequentially photolithograph and etch each stacked thin layer in three-dimensional direction and the electrodes of adjacent SHNO stacks;

[0095] Step 3, covering the whole top of the three-dimensional SHNO series-parallel array with insulating layer and metal layer by deposition, photolithography and etching processes;

[0096] Step 4, preparing the full-electrically-controlled three-dimensional spin Hall nano microwave oscillator series-parallel array based on exchange bias.

[0097] In this embodiment, first, thin films are deposited layer by layer by methods such as magnetron sputtering, and square columnar bodies are photolithographed on the deposited thin films. In the three-dimensional series-parallel SHNO unit, the antiferromagnetic layer 101, the ferromagnetic layer 102 and the strong spin-orbit coupling layer 104 are all deposited as squares of the same size, and other embodiments do not limit the shape. Then, according to different 3D series-parallel modes, the conductive layer and the insulating layer are deposited, and finally the electrodes 103 and the insulating layer 105 with the required specific shape and size are photolithographed and etched. The order of the adjacent antiferromagnetic layer and ferromagnetic layer in the double-layer SHNO unit and the adjacent antiferromagnetic layer and strong spin-orbit coupling layer in the three-layer SHNO unit can be exchanged, but the stacking order of the antiferromagnetic / ferromagnetic layer and the antiferromagnetic / ferromagnetic / strong spin-orbit coupling layer of each SHNO unit in the vertical direction should be consistent in the same three-dimensional series-parallel array embodiment.

[0098] As an optional embodiment, the spin nano oscillator further comprises a seed layer and a cover layer. The seed layer is arranged on the side of the antiferromagnetic layer opposite to the ferromagnetic layer, and the cover layer is arranged on the top layer of the oscillator. The selection of the seed layer material has a substantial influence on the exchange bias field generated by the exchange coupling between the antiferromagnetic layer and the ferromagnetic layer. The cover layer can effectively protect the spin nano oscillator and improve the stability and durability.

[0099] As an optional embodiment, the spin nano-oscillator can further comprise a barrier layer and a fixed layer. The ferromagnetic layer in the SHNO unit serves as a free layer, and the additional deposited barrier layer and fixed layer together realize a magnetic tunnel junction structure, which is arranged above the antiferromagnetic layer in the order of free layer, barrier layer, fixed layer, to improve the signal strength of the output by using the TMR effect. The shape of the antiferromagnetic layer and the magnetic tunnel junction is not limited, and the tunnel magnetoresistance (TMR) can be optimized to be more than 200% by adjusting the thickness of the barrier layer and the growth conditions such as annealing, and at the same time, the strength of the antiferromagnetic coupling between the antiferromagnetic layer and the free layer can be regulated by changing the thickness of the antiferromagnetic layer and the free layer. When the double-layer SHNO unit is applied to a spin Hall nano-oscillator array of single SHNO units vertically stacked in one-dimensional horizontal series connection, two-dimensional horizontal parallel connection, etc., the barrier layer and the fixed layer for detecting the output signal are applied on the top of the SHNO unit, and then the detection current is injected through the electrode layer additionally deposited above the fixed layer. The top electrodes of the multiple vertically stacked SHNO units are connected, and the power of the output microwave is improved. In the array of multiple SHNO units vertically stacked in two-dimensional vertical series-parallel connection, three-dimensional spin Hall nano-oscillator series-parallel connection, etc., the electrode layer is deposited above the fixed layer of the magnetic tunnel junction and extends to the four directions, and is connected with the top electrodes of the magnetic tunnel junctions of the left and right adjacent vertically stacked SHNO units and the top electrodes of the magnetic tunnel junctions of the upper and lower adjacent vertically stacked SHNO units, while injecting the detection current, and the signal power of the output is greatly improved by the TMR effect. Among them, the directions in which the vertically stacked detection signal electrodes are connected are perpendicular to the directions in which the currents are injected into the SHNO units, and are respectively distributed on different sides of the three-dimensional vertically stacked SHNO units.

[0100] In some embodiments, the spin Hall nano-oscillator 3D array comprises an antiferromagnetic layer 101, a ferromagnetic layer 102, and an insulating layer 105. The antiferromagnetic layer is MnN, and the thickness is preferably 30 nm. The ferromagnetic layer is CoFeB, which has strong perpendicular anisotropy, and the thickness is preferably 0.65 nm. The insulating layer is MgO, and the thickness is preferably 2 nm. The required flip threshold current of the magnetic moment is lower compared to the in-plane magnetization, which can improve the thermal stability and effectively reduce the power consumption. The high exchange bias enables MnN to be integrated into a spin valve, a magnetic tunnel junction, or combined with a ferromagnetic layer as a spin Hall device to generate a large exchange bias magnetic field, thereby replacing the externally applied magnetic field, and has a wide application prospect.

[0101] In some embodiments, the SHNO units in the SHNO three-dimensional series-parallel array can include a seed layer Ta, preferably 10 nm in thickness, located below the antiferromagnetic layer MnN, which facilitates the growth of MnN with strong magnetic crystalline anisotropy, enhances the exchange bias, and ensures maximum thermal stability. A high vertical exchange bias field of up to 3600 Oe at room temperature is generated by the exchange coupling between the ferromagnetic layer and the antiferromagnetic layer instead of an external magnetic field, realizing a fully electrically controlled spin Hall oscillator. Optionally, the SHNO three-dimensional series-parallel array can include an insulating layer MgO, preferably 2 nm in thickness, located at the top of the multi-layer oscillator stack.

[0102] In some embodiments, referring to Figure 11 In some embodiments, referring to In some embodiments, referring to

[0103] In some embodiments, referring to Figure 13 In some embodiments, referring to In some embodiments, referring to

[0104] In some embodiments, referring to Figure 14 In some embodiments, referring to In some embodiments, referring to

[0105] Generally, the magnetic order of the antiferromagnetic material is very stable to external magnetic field, unless the magnetic field heat treatment with temperature operation across the Néel temperature or a very strong magnetic field is applied to change the antiferromagnetic magnetic moment state. In the embodiment, the antiferromagnetic layer MnN is a strong spin-orbit coupling material, under the spin-orbit coupling effect of the antiferromagnetic layer MnN and the ferromagnetic layer CoFeB adjacent thereto, the current flowing through the antiferromagnetic layer is converted into a spin current to induce the precession of the magnetic moment of the ferromagnetic layer, and finally a periodic signal is output by detecting the change of the magnetic moment. The exchange bias field is provided to the ferromagnetic layer by the exchange coupling effect of the antiferromagnetic layer and the ferromagnetic layer, which can replace the in-plane or out-of-plane auxiliary field, and the exchange bias field of corresponding size and direction can be generated by changing the current size, direction and the like, so as to control the precession frequency of the magnetic moment of the ferromagnetic layer and realize the fully electrically controlled spin nanometer oscillator.

[0106] Reference Figure 16 A circuit connection schematic diagram of a fully electrically controlled three-dimensional spin Hall nanometer microwave oscillator array based on exchange bias, a current source inputs a direct current into the SHNO three-dimensional series-parallel array through the inductance of the Bias-Tee, and the spin current carrying angular momentum is generated by the antiferromagnetic layer of the double-layer SHNO unit or the strong spin-orbit coupling layer of the three-layer SHNO unit and is transmitted to the adjacent FM layer, so as to cause the magnetic moment in the FM layer to oscillate as shown in Figure 17 The output signal is detected according to the magnetoresistance effect such as anisotropic magnetoresistance AMR. Meanwhile, a large exchange bias field can be spontaneously generated by the exchange coupling effect of the AFM / FM double layer to replace the conventional external magnetic field, and the size and direction of the exchange bias field are adjusted in an electrically controlled magnetic manner, so as to change the frequency and other characteristics of the output microwave signal. Reference Figure 18 Under the condition of different sizes of the exchange bias field, the resonance frequency is different and increases with the increase of the exchange bias field, and the fully electrically controlled three-dimensional series-parallel spin Hall nanometer oscillator based on exchange bias can realize different output microwave signal frequencies.

[0107] In different fully electrically controlled spin Hall nanometer microwave oscillator three-dimensional series-parallel implementation structures based on exchange bias, the 3D array spin Hall oscillator is nonlinear, and the oscillators are easily coupled and synchronized, so that the problems of low output signal power and large linewidth can be improved to a large extent. The current flowing through the three-dimensional series-parallel SHNO structure generates an exchange bias in the in-plane or out-of-plane direction through the coupling effect between the AFM and the FM, which can replace the external magnetic field required for oscillation, so that the application is more convenient.

[0108] In summary, in order to solve the problem of weak signal of the spin Hall oscillator, a one-dimensional, two-dimensional, three-dimensional or multi-dimensional oscillator array can be used, and the synchronization or coupling between multiple devices can further improve the signal power and improve the signal strength. Based on the one-dimensional and two-dimensional array, the SHNO units are stacked in the vertical or horizontal direction to realize the three-dimensional series-parallel array structure of the SHNO, and the exchange bias field is generated by the exchange bias effect to promote the high-power output microwave signal of the 3D series-parallel array SHNO, and the structural complexity of the oscillator device requiring an external magnetic field is reduced, which has a wide application prospect.

[0109] In the above description of the present specification, the description of the terms "one embodiment", "another embodiment" or "certain embodiments" or the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0110] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

[0111] The above is a specific description of the preferred embodiments of the present application, but the present application is not limited to the above embodiments, and those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the present application, and these equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A three-dimensional spin-Hall nanovibrator series-parallel array, characterized in that, The spin Hall nanometer microwave oscillator unit comprises a plurality of double-layer thin film structures and / or a three-layer thin film structure; a plurality of spin Hall nanometer microwave oscillator units are stacked in a preset manner to form a three-dimensional spin Hall nanometer oscillator series-parallel array. The double-layer thin film structure spin Hall nanometer microwave oscillator unit is composed of an antiferromagnetic layer, a ferromagnetic layer above the antiferromagnetic layer, and left and right electrodes. The three-layer thin film structure spin Hall nanometer microwave oscillator unit is composed of an antiferromagnetic layer, a ferromagnetic layer above the antiferromagnetic layer, a strong spin-orbit coupling layer above the ferromagnetic layer, and left and right electrodes. The current passes through the left and right electrodes into the oscillator, is converted into a spin current in the strong spin-orbit coupling layer, and acts on the ferromagnetic layer magnetic moment; the high-frequency precession of the magnetic moment causes the resistance of the device to periodically change; the exchange coupling between the antiferromagnetic layer and the ferromagnetic layer generates a spontaneous exchange bias field, which finally outputs a microwave signal.

2. The three-dimensional spin-Hall nanovibrator series-parallel array of claim 1, wherein, There is an exchange bias effect at the interface between the antiferromagnetic layer and the ferromagnetic layer. When the current flows through the oscillator, the antiferromagnetic layer generates an in-plane or out-of-plane exchange bias field on the ferromagnetic layer under the influence of exchange coupling; the electrically controlled exchange bias field replaces the required additional external magnetic field, realizing field-free oscillation.

3. The three-dimensional spin-Hall nanovibrator series-parallel array of claim 1, wherein, In the double-layer thin film structure spin Hall nanometer microwave oscillator unit, the antiferromagnetic layer is an antiferromagnetic metal thin film. The current flowing through the antiferromagnetic layer generates a spin-orbit torque on the ferromagnetic layer, and the exchange coupling between the antiferromagnetic layer and the ferromagnetic layer generates a corresponding exchange bias field; under the synergistic action of the internal auxiliary field of the oscillator and the spin-orbit torque driving the ferromagnetic layer magnetic moment precession, the oscillator provides a microwave signal. In the three-layer thin film structure spin Hall nanometer microwave oscillator unit, the antiferromagnetic layer is an antiferromagnetic insulating thin film. The current flowing through the strong spin-orbit coupling layer generates a spin-orbit torque on the ferromagnetic layer, and the exchange coupling between the antiferromagnetic layer and the ferromagnetic layer generates a corresponding exchange bias field; under the synergistic action of the internal auxiliary field of the oscillator and the spin-orbit torque driving the ferromagnetic layer magnetic moment precession, the oscillator provides a microwave signal.

4. The three-dimensional spin-Hall nanovibrator series-parallel array of claim 3, wherein, The material of the antiferromagnetic metal thin film is MnN, CrN, FeMn, NiMn, IrMn, PtMn, PtPdMn, CrMn, or CrAl; The material of the antiferromagnetic insulating film is NiO, CoO, Ni x Co 1-x O, FeO, Fe2O3, Fe3O4, Cr2O3, FeF2, MnF2, or BiFeO3.

5. The three-dimensional spin-Hall nanowire oscillator array of claim 1, wherein, The spin Hall nanometer microwave oscillator unit further comprises a seed layer and a capping layer; the seed layer is arranged on the side of the antiferromagnetic layer opposite to the ferromagnetic layer, and the capping layer is arranged on the top layer of the oscillator.

6. The three-dimensional spin-Hall nanowire oscillator array of claim 1, wherein, The spin Hall nanometer microwave oscillator unit further comprises a barrier layer and a fixed layer. The ferromagnetic layer serves as a free layer, and together with the additionally deposited barrier layer and fixed layer, forms a magnetic tunnel junction; the magnetic tunnel junction is stacked on the bottom antiferromagnetic layer. The current passing through the antiferromagnetic layer is converted into a spin current and acts on the free layer magnetic moment; the high-frequency precession of the magnetic moment causes the resistance of the device to periodically change; the current passing through the fixed layer is detected, and the final output microwave signal is read using the TMR effect.

7. The three-dimensional spin-Hall nanowire oscillator array of claim 6, wherein, When the magnetic moment of the free layer is opposite to the magnetic moment of the fixed layer, it shows a high resistance state; when the magnetic moment of the free layer is the same as the magnetic moment of the fixed layer, it shows a low resistance state.

8. The three-dimensional spin-Hall nanowire oscillator array of claim 6, wherein, The spin Hall nanometer microwave oscillator unit further comprises a pinning layer, which is arranged on either side of the fixed layer; The pinning layer is arranged above the fixed layer as an interlayer of the fixed layer and the cover layer; or, The pinning layer is arranged below the fixed layer as an interlayer of the fixed layer and the barrier layer; The magnetization direction of the fixed layer is kept unchanged by pinning.

9. The three-dimensional spin-Hall nanowire oscillator array of claim 1, wherein, The material of the strong spin-orbit coupling layer is a non-magnetic heavy metal, an alloy material, an anti-ferromagnetic metal or a topological insulator. The material of the ferromagnetic layer is a ferromagnetic metal material.

10. A method of manufacture for fabricating a three-dimensional spin-Hall nano-oscillator series-parallel array according to any one of claims 1-9, characterized in that, The method comprises the following steps: Depositing thin films of the spin Hall nanometer microwave oscillator unit on a substrate to prepare spin Hall nanometer microwave oscillator units of the same size and shape through photolithography and etching; Growing insulating layers and conductive layers between adjacent spin Hall nanometer microwave oscillator units, and sequentially photolithographing and etching the stacked thin layers in three-dimensional direction and the electrodes of the adjacent spin Hall nanometer microwave oscillator unit stacks; Covering the whole top of the three-dimensional spin Hall nanometer oscillator series-parallel array with insulating layers and metal layers through deposition process, photolithography process and etching process; Preparation of an all-electric three-dimensional spin Hall nanometer microwave oscillator series-parallel array based on exchange bias.

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