Novel double-spin-transfer torque device

Abstract

The invention discloses a novel double-spin-transfer torque device. The device comprises a magnetic tunnel junction, a first gate electrode, a second gate electrode and a third gate electrode from bottom to top in sequence, wherein the magnetic tunnel junction comprises a bottom reference layer formed by ferromagnetic metal, a barrier layer formed by oxide and a free layer formed by ferromagnetic metal; a spin valve structure including a free layer shared with the magnetic tunnel junction, a spacer layer made of a spacer material, and a top reference layer made of ferromagnetic metal; the magnetic moment direction of the top reference layer is orthogonal to the magnetic moment directions of the free layer and the bottom reference layer, so that the efficiency of the spin transfer torque in the initial stage of data writing can be effectively improved, the incubation delay of the magnetic moment overturning of the free layer is reduced, and the spin valve structure does not generate obvious influence on the tunneling magnetic resistance of the whole device. The method can be used for improving the data writing speed of the spin-transfer torque magnetic tunnel junction and reducing the data writing power consumption.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic memory, and in particular to a novel dual spin-transfer torque device. Background Art

[0002] Spin Transfer Torque-Magnetic Random Access Memory (STT-MRAM) has the advantages of non-volatility, high density, high-speed and low-power data writing (write speed <10ns, write power consumption <~0.1pJ / bit), and is a key technology that is expected to break through the power consumption bottleneck of integrated circuits in the post-Moore era. The core structure of STT-MRAM is a magnetic tunnel junction MTJ for storing data, which consists of a reference layer composed of ferromagnetic metal, a barrier layer composed of oxide, and a free layer composed of ferromagnetic metal. The direction of the magnetic moment of the free layer is easily changed by external excitation, thereby switching in the two directions of the easy magnetization axis, while the direction of the magnetic moment of the reference layer is not easily changed by external excitation, and is thus fixed in a certain direction. When the directions of the magnetic moments of the free layer and the reference layer are parallel, the MTJ presents a low resistance state; when the directions of the magnetic moments of the free layer and the reference layer are antiparallel, the MTJ presents a high resistance state. In this way, the high and low resistance states of the MTJ can be used to store data "1" and "0" accordingly. According to the different directions of the easy magnetization axes of the free layer and the reference layer, STT-MRAM can be divided into the following types: Figure 1 (a) shows the perpendicular magnetic anisotropy MTJ (pMTJ) structure, and Figure 1 (b) In-plane MTJ (iMTJ) structure shown.

[0003] In actual operation, data can be written by passing a current through the MTJ in the z direction to generate STT. Whether the MTJ finally presents a high resistance state or a low resistance state depends on the polarity of the write current (flowing from the reference layer to the free layer or from the free layer to the reference layer). Figure 2As shown. When the current flows from the reference layer to the free layer, it first obtains the spin angular momentum with the same direction as the magnetic moment of the reference layer. When the spin-polarized current enters the free layer, the transverse component of its spin angular momentum will act on the free layer in the form of torque, forcing the magnetic moment of the free layer to be parallel to the reference layer; while for the current in the opposite direction, the reflection of the reference layer on the spin causes the magnetic moment of the free layer to obtain the opposite torque. According to the Landau-Lifshitz-Gilbert (LLG) equation, the magnitude of STT is proportional to sinθ (θ is the angle between the magnetic moment of the free layer and the magnetic moment of the reference layer). In the initial stage of STT-driven MTJ free layer magnetic moment reversal, since the magnetic moment of the free layer is close to parallel or antiparallel to the magnetic moment of the reference layer, the STT efficiency is extremely low at this time. The magnetic moment can only be reversed when the write current is large enough and after a sufficiently long incubation delay.

[0004] In order to improve the efficiency of STT in the initial stage of free layer magnetic moment reversal, thereby reducing the write power consumption of STT-MRAM and increasing the write speed, the industry and academia have proposed a variety of technical solutions. NNMojumber reported an MTJ with a tilted anisotropy (TMA) reference layer at the 2012 IEEE TED conference. Figure 3 (a) As shown. Since there is a certain angle between the reference layer magnetic moment and the free layer magnetic moment in the equilibrium state, the STT efficiency is significantly improved in the initial stage of writing. The simulation results show that when the easy magnetization axis of the reference layer is at an angle of 20° with the z direction, the critical write current is reduced by 80% compared with the traditional p-MTJ at a write speed of 2ns. However, this solution is difficult to implement experimentally.

[0005] IBM reported a new MTJ structure (Double MTJ: DMTJ) with double reference layers and double barrier layers at the IEEE IEDM conference in 2015. Figure 3 (b) As shown. By setting the magnetic moment directions of the top and bottom reference layers to be antiparallel, the upper and lower interfaces of the free layer can obtain the same STT. Finally, under the experimental condition that the spin polarization rate of the top reference layer is >0.5, the critical write current is reduced by 50% compared with the traditional p-MTJ. However, the introduction of the double barrier layer will affect the overall TMR of the device, making it difficult to achieve compatibility between high TMR and high-speed, low-power writing.

[0006] On this basis, IBM has proposed two improved structures. Figure 3As shown in (c), IBM reported a patent for a thermally assisted STT-MTJ in 2017, which changes the top reference layer of the DMTJ from perpendicular magnetic anisotropy to in-plane magnetic anisotropy, and through special material selection, the top reference layer has a lower Curie temperature. In the initial stage of writing, the upper and lower interfaces of the free layer can be simultaneously affected by the in-plane spin polarization STT from the top reference layer and the out-of-plane spin polarization STT from the bottom reference layer, and the STT efficiency is further improved compared to the DMTJ structure. After applying the write current for a certain period of time, the top reference layer will become non-magnetic or demagnetized under the influence of thermal effects, and no longer provide in-plane spin polarization current. After that, the reversal of the magnetic moment of the free layer will be dominated by the out-of-plane spin polarization current provided by the bottom reference layer. However, this scheme does not consider the impact of multiple thermal demagnetization treatments on the magnetic anisotropy of the top reference layer and the efficiency of in-plane polarized spin current generation, and the introduction of the double barrier layer will also affect the overall TMR of the device.

[0007] like Figure 3 As shown in (d), IBM reported a new MTJ structure (Double Spin Torque MTJ: DS-MTJ) with dual reference layers and a single barrier layer at the IEEE IEDM conference in 2021. Similar to the DMTJ structure, both the top reference layer and the bottom reference layer have perpendicular magnetic anisotropy, but in the DS-MTJ structure, the top barrier layer is replaced by a spacer material with an almost zero resistance area product (RA), so that the top reference layer, the spacer layer and the free layer form a spin valve structure. In the end, the experiment can obtain a TMR almost the same as that of the traditional p-MTJ, and reduce the critical write current by 50%, effectively solving the problem that it is difficult to achieve both high TMR and high-speed and low-power writing of DMTJ. However, since this structure can only generate out-of-plane spin-polarized current, there is still room for further optimization in improving STT efficiency. Summary of the invention

[0008] The purpose of the present invention is to provide a novel dual spin transfer torque device to solve the technical problem of low STT efficiency in the initial stage of STT-MRAM data writing, and to optimize the MTJ critical write current and write speed while obtaining high TMR.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] The present invention provides a novel dual spin-transfer torque device, which comprises, from bottom to top, the following components:

[0011] Magnetic tunnel junction: includes a bottom reference layer made of ferromagnetic metal, a barrier layer made of oxide, and a free layer made of ferromagnetic metal;

[0012] Spin valve structure: including a free layer shared with a magnetic tunnel junction, a spacer layer composed of a spacer material, and a top reference layer composed of a ferromagnetic metal;

[0013] The magnetic moment direction of the top reference layer is orthogonal to the magnetic moment directions of the free layer and the bottom reference layer.

[0014] Furthermore, the top reference layer has in-plane magnetic anisotropy, and the direction of its easy magnetization axis is determined by the annealing direction. The bottom reference layer and the free layer have perpendicular magnetic anisotropy.

[0015] Furthermore, artificial antiferromagnetic or antiferromagnetic materials are included to fix the magnetic moment directions of the top reference layer and the bottom reference layer. The artificial antiferromagnetic or antiferromagnetic materials are arranged above the top ferromagnetic reference layer or below the bottom ferromagnetic reference layer.

[0016] Furthermore, the top reference layer has perpendicular magnetic anisotropy. The bottom reference layer and the free layer have in-plane magnetic anisotropy, the direction of the easy magnetization axis of the bottom reference layer is determined by the annealing direction, and the direction of the easy magnetization axis of the free layer is determined by the long axis direction of the magnetic tunnel junction, and it is necessary to ensure that the annealing direction is consistent with the long axis direction of the magnetic tunnel junction.

[0017] Furthermore, the barrier layer is a metal oxide, including magnesium oxide or aluminum oxide.

[0018] Furthermore, the material of the spacer layer includes Ru or Cu, and the thickness is 1-20 nm.

[0019] Furthermore, the magnetic tunnel junction and the spin valve structure are in the shape of a cylinder or an elliptical cylinder.

[0020] Based on the above technical solution, the embodiments of the present invention can at least produce the following technical effects:

[0021] The present invention can improve the efficiency of STT in the initial stage of data writing and reduce the incubation delay of the magnetic moment reversal of the free layer by introducing a top reference layer that is orthogonal to the bottom reference layer and the free layer. In addition, since the RA of the spacer layer is almost 0, the spin valve structure composed of the spacer layer, the free layer and the top reference layer will not have a significant effect on the TMR of the entire device. The novel dual spin transfer torque device proposed by the present invention can achieve high-speed, low-power data writing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0023] Figure 1 Schematic diagram of the classic structure of STT-MRAM in the prior art; (a) is a schematic diagram of the p-MTJ structure, and (b) is a schematic diagram of the i-MTJ structure;

[0024] Figure 2 It is a schematic diagram of the principle of STT driving the magnetic moment reversal of the free layer in the prior art;

[0025] Figure 3 Schematic diagram of a technical solution that can be used to improve STT efficiency in the prior art; wherein (a) is a schematic diagram of an MTJ structure with a TMA reference layer, (b) is a schematic diagram of a DMTJ structure, (c) is a schematic diagram of a thermally assisted STT-MTJ structure, and (d) is a schematic diagram of a DS-MTJ structure;

[0026] Figure 4 Schematic diagram of the structure of the novel dual spin-transfer torque device of the present invention; wherein (a) and (b) are schematic diagrams of the device structure in which the top reference layer has in-plane anisotropy, and the free layer and the bottom reference layer have perpendicular magnetic anisotropy, (a) is a front view, (b) is a top view, (c) and (d) are schematic diagrams of the device structure in which the top reference layer has perpendicular magnetic anisotropy, and the free layer and the bottom reference layer have in-plane magnetic anisotropy, (c) is a front view, and (d) is a top view;

[0027] Figure 5 Schematic diagram of the structure of Example 1 of the present invention; (a) is a front view, and (b) is a top view;

[0028] Figure 6 Schematic diagram of the structure of Example 2 of the present invention; (a) is a front view, and (b) is a top view;

[0029] Figure 7 Schematic diagram of the structure of Example 3 of the present invention; (a) is a front view, and (b) is a top view;

[0030] Figure 8 Schematic diagram of the structure of Example 4 of the present invention; (a) is a front view, and (b) is a top view. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0032] In order to improve the efficiency of STT in the initial stage of magnetic moment reversal of the free layer, thereby reducing the write power consumption of STT-MRAM and increasing the write speed, the present invention introduces an additional top reference layer on the basis of the traditional STT-MTJ structure, and the easy magnetization axis direction of the top reference layer is orthogonal to the easy magnetization axis direction of the free layer and the bottom reference layer. In the initial stage of magnetic moment reversal, the free layer simultaneously receives STT provided by spin polarization currents in orthogonal directions, so that the STT efficiency is significantly improved and the incubation delay is significantly shortened. In addition, the present invention uses a spacing material with a lower RA as a spacing layer between the top reference layer and the free layer, which can effectively avoid the influence of the introduction of the top reference layer on the TMR of the device. Therefore, the present invention is expected to achieve high-speed, low-power STT data writing while obtaining high TMR.

[0033] Based on this, this embodiment discloses a novel dual spin-transfer torque device. Figure 4 (a) and Figure 4 As shown in (b), in this embodiment, the novel dual spin-transfer torque device comprises a storage unit composed of a spin valve structure and an MTJ structure. The core structure of the MTJ is a bottom reference layer composed of a ferromagnetic metal, a barrier layer composed of an oxide, and a free layer composed of a ferromagnetic metal. The core structure of the spin valve is a top reference layer composed of a ferromagnetic metal, a spacer layer composed of a spacer material, and a free layer shared with a magnetic tunnel junction.

[0034] In this embodiment, the thickness range of the barrier layer and the spacer layer must be kept moderate, which can allow enough polarized spin currents from the reference layer to tunnel to the free layer to ensure that the spin polarization rate is large enough, and can cancel the coupling between the free layer and the reference layer so that the magnetic moment of the free layer can be freely flipped.

[0035] In this embodiment, the top reference layer and the bottom reference layer further include artificial antiferromagnetic or antiferromagnetic materials for fixing the direction of the magnetic moment of the reference layer. It can be understood that the artificial antiferromagnetic material is composed of two layers of ferromagnetic metal separated by a spacer layer material, and the two layers of ferromagnetic metal form a strong antiferromagnetic coupling through the Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction, in which one ferromagnetic layer forms a strong ferromagnetic coupling with the reference layer, thereby providing a pinning effect for the magnetic moment of the reference layer. The antiferromagnetic material can directly provide a pinning effect for the magnetic moment of the reference layer through the interface exchange bias effect, but annealing treatment is required. For a reference layer with perpendicular magnetic anisotropy, an artificial antiferromagnetic material is usually used to fix the direction of the magnetic moment of the reference layer, and for a reference layer with in-plane magnetic anisotropy, an antiferromagnetic material is usually used to fix the direction of the magnetic moment of the reference layer.

[0036] In an optional embodiment, the bottom reference layer and the free layer have perpendicular magnetic anisotropy. The top reference layer has an in-plane magnetic anisotropy, and the direction of its easy magnetization axis is determined by the annealing direction and is orthogonal to the easy magnetization axis direction of the free layer and the bottom reference layer. Figure 4 (b) shows that its direction is the +x direction, and its direction can also be any direction in the xoy plane. The shape of the magnetic tunnel junction and spin valve structure is a cylinder (such as Figure 4 (as shown in (b)).

[0037] It can be understood that when the free layer and the bottom reference layer have perpendicular magnetic anisotropy, the anisotropy is derived from the interface anisotropy rather than the annealing direction and the device shape. Therefore, in this optional embodiment, the shape of the magnetic tunnel junction and the spin valve structure is a cylinder;

[0038] In another optional embodiment, the top reference layer has perpendicular magnetic anisotropy. The bottom reference layer and the free layer have in-plane magnetic anisotropy, the direction of the easy magnetization axis of the bottom reference layer is determined by the annealing direction, and the direction of the easy magnetization axis of the free layer is determined by the long axis direction of the magnetic tunnel junction, both of which are orthogonal to the easy magnetization axis direction of the top reference layer, such as Figure 4 (c) As shown. In-plane magnetic field annealing Figure 4 (d) shows that its direction is the +x direction. It can also be any direction in the xoy plane, but it is necessary to ensure that the annealing direction is consistent with the long axis direction of the magnetic tunnel junction. The shape of the magnetic tunnel junction and the spin valve structure is an elliptical column (such as Figure 4 (d)).

[0039] It can be understood that when the free layer has in-plane anisotropy, the direction of its easy magnetization axis is provided by the shape anisotropy of the device, that is, it is determined by the long axis direction of the magnetic tunnel junction. Therefore, in this optional embodiment, the shape of the magnetic tunnel junction and the spin valve structure is an elliptical cylinder; and for the bottom reference layer with in-plane magnetic anisotropy, due to the introduction of antiferromagnetic materials to form an interface exchange bias, the direction of its easy magnetization axis is determined by the direction of the external magnetic field during annealing. Therefore, in order to obtain a higher TMR, it is necessary to ensure that the directions of the easy magnetization axes of the free layer and the bottom reference layer are consistent, that is, to ensure that the annealing direction is consistent with the long axis direction of the magnetic tunnel junction.

[0040] Furthermore, the free layer is a CoFeB alloy, and the common element ratio can be Co 20 Fe 60 B 20 、Co 40 Fe 40 B 20 or Co 60 Fe 20 B 20 The numbers here represent the percentage of elements, but are not limited to the element ratios described here. In practical applications, there is no limit on the ratio of the content of each element in the alloy, and there is no limit on the ratio of thickness of each alloy in different alloy combinations, which can be flexibly determined according to actual conditions. The materials are not limited to the materials listed above. The technical solution of forming a new dual spin transfer torque device using materials that can realize the free layer function should also be within the scope of protection of the present invention.

[0041] Furthermore, the barrier layer is a metal oxide, including magnesium oxide and aluminum oxide. In practical applications, the material of the barrier layer is not limited, and can be flexibly determined according to actual conditions. The material is not limited to the materials listed above. The technical solution of forming a new dual spin-transfer torque device using materials that can realize the function of the barrier layer should also be within the scope of protection of the present invention.

[0042] Furthermore, the top reference layer and the bottom reference layer are CoFeB or CoFe alloy, and the common element ratio of CoFeB can be Co 20 Fe 60 B 20 、Co 40 Fe 40 B 20 or Co 60 Fe 20 B 20 The commonly used element ratio of CoFe can be Co 30 Fe 70 or Co 50 Fe 50The numbers here represent the percentage of elements, but are not limited to the element ratios described here. In practical applications, there is no limit on the ratio of the content of each element in the alloy, and there is no limit on the ratio of thickness of each alloy in different alloy combinations, which can be flexibly determined according to actual conditions. The materials are not limited to the materials listed above. The technical solution of forming a new dual spin transfer torque device using materials that can realize the function of the reference layer should also be within the scope of protection of the present invention.

[0043] Furthermore, the artificial antiferromagnetic material for fixing the reference layer with perpendicular magnetic anisotropy, the two layers of ferromagnetic metal are composed of Co / Pt multilayer films of different thicknesses. The spacer layer for forming the RKKY coupling effect is metal Ru. The antiferromagnetic material for fixing the reference layer with in-plane anisotropy includes but is not limited to alloys such as IrMn and PtMn. The commonly used element ratio of IrMn can be Ir 25 Mn 75 , Ir 20 Mn 80 The common element ratio of PtMn can be Pt 50 Mn 50 In practical applications, there is no limitation on artificial antiferromagnetic materials and antiferromagnetic materials, which can be flexibly determined according to actual conditions. The materials are not limited to the materials listed above. The technical solution of forming a new dual spin-transfer torque device using materials that can realize the function of fixing the magnetic moment direction of the reference layer should also be within the protection scope of the present invention.

[0044] Furthermore, the thickness of the spacer layer is 1-20 nm, and the material includes but is not limited to Ru, Cu, etc. In practical applications, the material of the spacer layer is not limited to the materials listed above, and the technical solution of forming a magnetic random access memory using materials that can realize the function of the spacer layer should also be within the protection scope of the present invention.

[0045] The present invention will be further described below through several specific examples.

[0046] Example 1

[0047] like Figure 5 As shown, this specific example includes a core structure of Co 20 Fe 60 B 20 / MgO / Co 20 Fe 60 B 20 The p-MTJ and core structure are Co 20 Fe 60 B 20 / Cu / Co 20 Fe 60 B 20 The top reference layer Co20 Fe 60 B 20 Antiferromagnetic Ir is set on top 20 Mn 80 To fix the magnetic moment direction, the top Co 20 Fe 60 B 20 The easy magnetization axis of the reference layer is in the ±x direction, Co 20 Fe 60 B 20 Free layer and Co 20 Fe 60 B 20 The easy magnetization axis of the bottom reference layer is in the ±z direction, where Co 20 Fe 60 B 20 Artificial antiferromagnetic (Co / Pt)6 / Ru(Co / Pt)3 is set under the bottom reference layer to fix the magnetic moment direction. The overall shape of the device is cylindrical.

[0048] Example 2

[0049] like Figure 6 As shown, this specific example includes a core structure of Co 20 Fe 60 B 20 / MgO / Co 20 Fe 60 B 20 The p-MTJ and core structure are Co 20 Fe 60 B 20 / Ru / Co 20 Fe 60 B 20 The top reference layer Co 20 Fe 60 B 20 Antiferromagnetic Ir is set on top 20 Mn 80 To fix the magnetic moment direction, the in-plane magnetic field annealing direction is at a 45° angle to the +x direction, and the top reference layer Co 20 Fe 60 B 20 The easy magnetization axis of the magnetic moment is in the direction of 45° or 225° with the +x axis. 20 Fe 60 B 20 Free layer and Co 20 Fe 60 B 20 The easy axis direction of the magnetic moment of the bottom reference layer is ±z direction, where Co 20 Fe 60 B20 Artificial antiferromagnetic (Co / Pt)6 / Ru(Co / Pt)3 is set under the bottom reference layer to fix the magnetic moment direction. The overall shape of the device is cylindrical.

[0050] Example 3

[0051] like Figure 7 As shown, this specific example includes a core structure of Co 20 Fe 60 B 20 / MgO / Co 20 Fe 60 B 20 The i-MTJ and core structure are Co 20 Fe 60 B 20 / Ru / Co 20 Fe 60 B 20 The bottom reference layer Co 20 Fe 60 B 20 Antiferromagnetic Pt is set below 50 Mn 50 To fix the magnetic moment direction, the bottom Co 20 Fe 60 B 20 The easy magnetization axis direction of the reference layer and the free layer is ±x direction, Co 20 Fe 60 B 20 The easy magnetization axis direction of the magnetic moment of the top reference layer is in the ±z direction, and an artificial antiferromagnetic (Co / Pt)6 / Ru(Co / Pt)3 is set on top to fix the magnetic moment direction. The overall shape of the device is an elliptical cylinder.

[0052] Example 4

[0053] like Figure 8 As shown, this specific example includes a core structure of Co 20 Fe 60 B 20 / MgO / Co 20 Fe 60 B 20 The i-MTJ and core structure are Co 20 Fe 60 B 20 / Cu / Co 20 Fe 60 B 20 The bottom reference layer Co 20 Fe 60 B 20 Antiferromagnetic Pt is set below 50Mn 50 For fixing the direction of magnetic moment, the in-plane magnetic field annealing direction is 45° with the +x direction, and the easy magnetization axis direction of the bottom reference layer and free layer magnetic moment is 45° or 225° with the +x axis. 20 Fe 60 B 20 The easy magnetization axis direction of the magnetic moment of the top reference layer is in the ±z direction, and an artificial antiferromagnetic (Co / Pt)6 / Ru(Co / Pt)3 is set on top to fix the magnetic moment direction. The overall shape of the device is an elliptical cylinder.

[0054] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of the present invention to be protected is defined by the attached claims and their equivalents.

Claims

1. A novel dual spin-transfer torque device, characterized in that: The devices include, from bottom to top: Magnetic tunnel junction: includes a bottom reference layer made of ferromagnetic metal, a barrier layer made of oxide, and a free layer made of ferromagnetic metal; Spin valve structure: including a free layer shared with a magnetic tunnel junction, a spacer layer composed of a spacer material, and a top reference layer composed of a ferromagnetic metal; The magnetic moment direction of the top reference layer is orthogonal to the magnetic moment directions of the free layer and the bottom reference layer.

2. The novel dual spin-transfer torque device according to claim 1, characterized in that: The top reference layer has in-plane magnetic anisotropy, and the direction of its easy magnetization axis is determined by the annealing direction; the bottom reference layer and the free layer have perpendicular magnetic anisotropy.

3. The novel dual spin-transfer torque device according to claim 1, characterized in that: The top reference layer has perpendicular magnetic anisotropy; the bottom reference layer and the free layer have in-plane magnetic anisotropy, the easy magnetization axis direction of the bottom reference layer is determined by the annealing direction, and the easy magnetization axis direction of the free layer is determined by the long axis direction of the magnetic tunnel junction, ensuring that the annealing direction is consistent with the long axis direction of the magnetic tunnel junction.

4. The novel dual spin-transfer torque device according to claim 1, characterized in that: It also includes artificial antiferromagnetic or antiferromagnetic materials for fixing the magnetic moment directions of the top reference layer and the bottom reference layer. The artificial antiferromagnetic or antiferromagnetic materials are arranged above the top ferromagnetic reference layer or below the bottom ferromagnetic reference layer.

5. The novel dual spin-transfer torque device according to claim 1, characterized in that: The barrier layer is a metal oxide, including magnesium oxide or aluminum oxide.

6. The novel dual spin-transfer torque device according to claim 1, characterized in that: The material of the spacer layer includes Ru or Cu, and the thickness is 1-20 nm.

7. The novel dual spin-transfer torque device according to claim 1, characterized in that: The magnetic tunnel junction and the spin valve structure are in the shape of a cylinder or an elliptical cylinder.

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