Artificial antiferromagnetic multilayer film structure and magnetic random access memory including the same

Abstract

The present invention relates to artificial antiferromagnetic multilayer film structures and magnetic random access memories including the same. According to an embodiment, an artificial antiferromagnetic multilayer film structure can include: an in-plane field coupling layer including a first ferromagnetic layer and a second ferromagnetic layer formed of a ferromagnetic conductive material, and a first spacer layer located between the first and second ferromagnetic layers, the first spacer layer being formed of a non-magnetic conductive material and inducing antiferromagnetic coupling between the first and second ferromagnetic layers; a free magnetic layer including a third ferromagnetic layer and a fourth ferromagnetic layer formed of a ferromagnetic conductive material, and a spin Hall effect layer located between the third and fourth ferromagnetic layers, the spin Hall effect layer being formed of a material having a spin Hall effect and inducing antiferromagnetic coupling between the third and fourth ferromagnetic layers; and an intermediate layer located between the in-plane field coupling layer and the free magnetic layer, the intermediate layer being formed of a non-magnetic material.

Description

Technical Field

[0001] This invention relates generally to the field of spintronics, and more particularly to an artificial antiferromagnetic multilayer structure and a magnetic random access memory including said artificial antiferromagnetic multilayer structure. Background Technology

[0002] Artificial antiferromagnetic (SAF) structures are widely used in spintronics due to their resistance to external magnetic field interference, zero stray field, and high thermal stability. For example, in the memory cells of magnetic random access memory (MRAM), SAF structures are often used as free layers or reference layers (also called fixed layers or pinned layers) of magnetic tunnel junctions (MTJs) to improve the thermal stability and perpendicular magnetic anisotropy of the device.

[0003] Currently, data writing methods for current-driven MRAM can generally be divided into two categories. The first category is Spin Transfer Torque (STT) driven type, which utilizes the spin polarization effect generated when current flows perpendicularly through the reference layer. The spin-polarized current generates a spin transfer torque that flips the magnetic moment of the free layer in the memory cell, thereby achieving a change in high and low resistance states and completing the data writing of the memory cell. A major problem with STT-MRAM is the high current density during data writing. When data is written frequently, it can easily damage, for example, the barrier layer in the MTJ, thus affecting the lifespan of the MRAM memory cell. The second category is Spin-orbit Torque (SOT) driven type, which utilizes the spin current generated when current flows through a material with a strong spin-orbit coupling effect to flip the magnetic moment of the free layer in the memory cell, thereby achieving data writing of the memory cell. Compared to the former, the write current in SOT-MRAM can be an in-plane current flowing through the spin-orbit coupling material, without needing to flow perpendicularly through the magnetic tunnel junction. Therefore, it features fast write speeds and read-write separation, overcoming the short device lifetime issue of STT-MRAM. Thus, SOT-MRAM has great application potential in the future information storage field. However, when utilizing the SOT effect to achieve the reversal of the magnetic moment in an artificial antiferromagnetic structure, an external magnetic field or equivalent magnetic field needs to be applied in the in-plane direction, which severely hinders the application of artificial antiferromagnetic structures in SOT-MRAM. Summary of the Invention

[0004] To address the above and other technical problems, this invention is proposed. In this invention, an interlayer exchange-coupled bias magnetic field is applied to the free magnetic layer using an in-plane field coupling layer. The direction of the bias magnetic field can be parallel or antiparallel to the direction of the flipping current, thereby allowing the free magnetic layer to be flipped without an external magnetic field. Furthermore, both the in-plane field coupling layer and the free magnetic layer can have an artificial antiferromagnetic structure. A spin Hall effect layer is used as an intermediate spacer layer in the free magnetic layer to both generate spin current through spin-orbit coupling and induce antiferromagnetic coupling. The fully artificial antiferromagnetic structure of this invention reduces the net magnetic moment of the device, thereby increasing device density and improving the device's thermal stability.

[0005] According to one embodiment, an artificial antiferromagnetic multilayer film structure is provided, comprising: an in-plane field coupling layer including a first ferromagnetic layer and a second ferromagnetic layer formed of a ferromagnetically conductive material, and a first spacer layer located between the first ferromagnetic layer and the second ferromagnetic layer, the first spacer layer being formed of a non-magnetically conductive material and inducing antiferromagnetic coupling between the first ferromagnetic layer and the second ferromagnetic layer; a free magnetic layer including a third ferromagnetic layer and a fourth ferromagnetic layer formed of a ferromagnetically conductive material, and a spin Hall effect layer located between the third ferromagnetic layer and the fourth ferromagnetic layer, the spin Hall effect layer being formed of a material having a spin Hall effect and inducing antiferromagnetic coupling between the third ferromagnetic layer and the fourth ferromagnetic layer; and an intermediate layer located between the in-plane field coupling layer and the free magnetic layer, the intermediate layer being formed of a non-magnetic material.

[0006] In some embodiments, the first ferromagnetic layer and the second ferromagnetic layer have in-plane magnetic anisotropy, and the third ferromagnetic layer and the fourth ferromagnetic layer have perpendicular magnetic anisotropy.

[0007] In some embodiments, the intermediate layer has a thickness in the range of 0.4-1.5 nm, such that the in-plane field coupling layer applies an interlayer coupling bias magnetic field to the free magnetic layer through the intermediate layer.

[0008] In some embodiments, the intermediate layer is formed of a non-magnetic insulating material.

[0009] In some embodiments, the third ferromagnetic layer in the free magnetic layer is closer to the in-plane field coupling layer than the fourth ferromagnetic layer, and the third ferromagnetic layer has a greater thickness than the fourth ferromagnetic layer.

[0010] According to another embodiment, a magnetic random access memory (MRM) is provided, comprising a plurality of memory cells, each memory cell comprising: the aforementioned artificial antiferromagnetic multilayer film structure; a tunnel barrier layer formed on the free magnetic layer and made of a non-magnetic insulating material; and a reference magnetic layer formed on the tunnel barrier layer, comprising a fifth ferromagnetic layer and a sixth ferromagnetic layer formed of a ferromagnetic conductive material, and a second spacer layer located between the fifth ferromagnetic layer and the sixth ferromagnetic layer, the second spacer layer being formed of a non-magnetic conductive material and inducing antiferromagnetic coupling between the fifth ferromagnetic layer and the sixth ferromagnetic layer.

[0011] In some embodiments, the fifth and sixth ferromagnetic layers have perpendicular magnetic anisotropy.

[0012] In some embodiments, the free magnetic layer is configured to receive in-plane write current to flip the magnetic moment of the free magnetic layer, and the memory cell is configured to receive vertical read current to read the resistance state of the memory cell.

[0013] In some embodiments, the direction of the in-plane write current is substantially parallel or antiparallel to the direction of the interlayer coupling bias magnetic field applied by the in-plane field coupling layer to the free magnetic layer.

[0014] In some embodiments, the thickness of the tunnel barrier layer is greater than the thickness of the intermediate layer.

[0015] The above and other features and advantages of the present invention will become apparent from the following description of exemplary embodiments taken in conjunction with the accompanying drawings. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of an artificial antiferromagnetic multilayer film structure according to an embodiment of the present invention.

[0017] Figure 2 This is a curve showing the relationship between anomalous Hall magnetoresistance and current density obtained by measuring an artificial antiferromagnetic multilayer film structure according to an embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram of a magnetic random access memory (MRM) storage unit including an artificial antiferromagnetic multilayer film structure according to an embodiment of the present invention.

[0019] Figure 4 Yes Figure 3 A schematic diagram illustrating read and write operations on a storage unit.

[0020] Figure 5 This is a graph of magnetoresistance versus external magnetic field obtained by measuring a magnetic random access memory (MRM) storage cell comprising an artificial antiferromagnetic multilayer film structure according to an embodiment of the present invention under an external magnetic field.

[0021] Figure 6 This is a curve showing the relationship between the magnetoresistance and the write current of a magnetic random access memory (MRMemory) cell comprising an artificial antiferromagnetic multilayer film structure according to an embodiment of the present invention. Detailed Implementation

[0022] Hereinafter, exemplary embodiments according to this application will be described in detail with reference to the accompanying drawings. Note that the drawings may not be drawn to scale. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments of this application, and this application is not limited to the exemplary embodiments described herein.

[0023] Figure 1 This is a schematic diagram of an artificial antiferromagnetic multilayer film structure 100 according to an embodiment of the present invention. (Refer to...) Figure 1 The artificial antiferromagnetic multilayer film structure 100 includes a seed layer 102, an in-plane field coupling layer (IMF) 110, an intermediate layer 120, a magnetic free layer (FL) 130 and a cap layer 140 sequentially formed on a substrate 101.

[0024] The substrate 101 can be a commonly used insulating substrate, such as a silicon dioxide substrate, a glass substrate, a quartz substrate, etc., or it can be a semiconductor substrate, such as a silicon substrate, a silicon-on-insulator (SOI) substrate, etc.

[0025] Seed layer 102, also known as buffer layer, may comprise a single or multiple layers to provide a tight bond with substrate 101 and to provide a good growth or deposition surface for layers formed thereon. Seed layer 102 may be formed of a non-magnetic metal or alloy material with good electrical conductivity, examples of which include Ta, W, Ru, Pt, etc., and its thickness may be in the range of approximately 1-10 nm, but is not limited thereto.

[0026] Each of the in-plane field coupling layer 110 and the magnetic free layer 130 may have an artificial antiferromagnetic structure. Specifically, the in-plane field coupling layer 110 may include a first ferromagnetic layer (FM1) 112, a second ferromagnetic layer (FM2) 116, and a spacer layer 114 located between them. The first ferromagnetic layer 112 and the second ferromagnetic layer 116 may each be formed of a ferromagnetic metal or alloy material, with a thickness ranging from 0.5 to 10 nm, and may have an in-plane magnetization direction. The spacer layer 114 may include a single-layer or multi-layer thin film made of a non-magnetic metal or alloy material, with a thickness ranging from 0.4 to 2.5 nm. Studies on artificial antiferromagnetic structures have found that when the thickness of the intermediate spacer layer varies, the ferromagnetic layers on both sides can vary between ferromagnetic (parallel) coupling and antiferromagnetic (antiparallel) coupling. Therefore, the material and thickness of the spacer layer 114 can be selected to induce antiferromagnetic coupling between the first ferromagnetic layer 112 and the second ferromagnetic layer 116, thereby making the magnetic moments of the first ferromagnetic layer 112 and the second ferromagnetic layer 116 antiparallel to each other, forming an artificial antiferromagnetic structure. Examples of structures for the in-plane field coupling layer 110 include, but are not limited to, Co / Ru / Co, Co / W / Co, Co / W / Ir / Co, Co / Ta / Co, Co / Ta / Co, Co / Ta / Ir / Co, Co / Pt / Co, NiFe / Ru / NiFe, NiFe / Ir / NiFe, CoFeB / Ru / CoFeB, etc.

[0027] The magnetic free layer 130 may include a third ferromagnetic layer (FM3) 132, a fourth ferromagnetic layer (FM4) 136, and a spin Hall effect layer (SHE) 134 located between them. The third ferromagnetic layer 132 and the fourth ferromagnetic layer 136 may each be formed of a ferromagnetic metal or alloy material, with a thickness ranging from 0.5 to 10 nm, and may have a perpendicular magnetization direction. The thicknesses of the third ferromagnetic layer 132 and the fourth ferromagnetic layer 136 may differ from each other; for example, the thickness of the third ferromagnetic layer 132 closer to the in-plane field coupling layer 110 may be greater than the thickness of the fourth ferromagnetic layer 136 farther from the in-plane field coupling layer 110, thereby ensuring that the free layer 130 is properly flipped under the in-plane bias magnetic field applied by the in-plane field coupling layer 110. The spin Hall effect layer 134 can be formed of a nonmagnetic metallic material exhibiting the spin Hall effect, i.e., strong spin-orbit coupling. Examples include, but are not limited to, heavy metals such as Pt, Ta, W, and Ir, or alloys thereof, with a thickness ranging from 0.4 to 2.5 nm. It should be noted that the material and thickness of the spin Hall effect layer 134 can be chosen to induce antiferromagnetic coupling between the third ferromagnetic layer 132 and the fourth ferromagnetic layer 136, such that the magnetic moments of the third ferromagnetic layer 132 and the fourth ferromagnetic layer 136 are antiparallel to each other, forming an artificial antiferromagnetic structure. Examples of structures for the magnetic free layer 130 include, but are not limited to, CoFeB / W / CoFeB, CoFeB / Ta / CoFeB, CoFeB / Pt / CoFeB, etc.

[0028] The intermediate layer 120 is located between the in-plane field coupling layer 110 and the magnetic free layer 130. It can be a non-magnetic insulating barrier layer, such as formed of insulating barrier materials like MgO or Al2O3; or it can be a non-magnetic conductive material, such as Ru, Ir, Cu, W, or Ta. The thickness of the intermediate layer 120 can be in the range of approximately 0.4-1.5 nm. The material of the intermediate layer 120 can be appropriately selected to provide an interface for the ferromagnetic material in the free magnetic layer formed thereon, so as to facilitate the formation of perpendicular magnetic anisotropy. On the other hand, the relatively thin thickness of the intermediate layer 120 allows the magnetic moment in the free magnetic layer 130 to be affected by the interlayer coupling magnetic field generated by the in-plane magnetic anisotropy ferromagnetic layer in the in-plane field coupling layer 110, thereby biasing the perpendicular magnetic moment in the free magnetic layer 130 and generating an in-plane component.

[0029] The cap layer 140 may include a metal layer with good conductivity and corrosion resistance, such as W, Ta, Ru, Pt, Au, Ir, etc., with a thickness ranging from, for example, 5-10 nm, thereby protecting the underlying layer from oxidation and moisture corrosion. In some embodiments, the cap layer 140 may also include an insulating layer, such as an MgO or Al2O3 layer, located between the metal cap layer and the free layer 130, with a thickness ranging from 0.5-3 nm. The insulating barrier cap layer can provide a good interface for the adjacent magnetic layer below, ensuring that its vertical magnetic anisotropy is not affected by the metal cap layer above. At the same time, because it is as thin as the intermediate layer 120, it allows vertical current tunneling through the insulating barrier layer.

[0030] It should be noted that in the artificial antiferromagnetic multilayer film structure 100, all magnetic layers are artificial antiferromagnetic structures. Therefore, it has only a very small leakage magnetic field, which will not affect adjacent magnetic elements. It can increase the density of magnetic elements and improve their thermal stability, etc.

[0031] The artificial antiferromagnetic multilayer structure 100 can be used as a Hall device. During writing, an in-plane current can be applied to the artificial antiferromagnetic multilayer structure 100. The direction of this in-plane current can be parallel or antiparallel to the direction of the in-plane bias magnetic field applied by the in-plane field coupling layer 110 to the magnetic free layer 130. Although not shown, electrodes can be formed on both sides of the artificial antiferromagnetic multilayer structure 100 to apply the in-plane current. The current flowing through the spin Hall effect layer 134 accumulates on its upper and lower surfaces due to spin-orbit coupling and injects spin current into the adjacent magnetic layers 132 and 136. The interaction between the spin current and the magnetic moments of the magnetic layers produces a spin-orbit torque effect, which, under the combined action of the in-plane bias magnetic field applied by the in-plane field coupling layer 110 to the magnetic free layer 130, flips the direction of the magnetic moment of the free layer 130. Because of the in-plane bias magnetic field applied by the in-plane field coupling layer 110, it is not necessary to apply an external magnetic field to the artificial antiferromagnetic multilayer film structure 100; the magnetic moment reversal of the free layer 130 can be achieved solely through an in-plane current. During readout, a small in-plane current can be applied, and the Hall voltage signal of the artificial antiferromagnetic multilayer film structure 100 can be measured in a direction perpendicular to the current direction. The direction of the magnetic moment of the free magnetic layer 130 can be determined based on the measured Hall voltage.

[0032] Figure 2 This is a curve showing the relationship between anomalous Hall magnetoresistance and current density obtained by measuring an artificial antiferromagnetic multilayer film structure 100 according to an embodiment of the present invention, where the horizontal axis represents the current density J. x The vertical axis represents the anomalous Hall magnetoresistive R. xyThe value can be calculated by dividing the measured Hall voltage by the applied readout current. The artificial antiferromagnetic multilayer structure 100 has the following structure from the substrate side: W(1nm) / Co(2.2nm) / Ir(0.5nm) / W(0.4nm) / Co(2nm) / MgO(0.8nm) / CoFeB(1.3nm) / W(0.9nm) / CoFeB(0.9nm) / MgO(2nm) / W(2nm), where Co(2.2nm) / Ir(0.5nm) / W(0.4nm) / Co(2nm) serves as the in-plane field coupling layer 110, and CoFeB(1.3nm) / W(0.9nm) / CoFeB(0.9nm) serves as the free layer 130. Before measurement, an external magnetic field can be applied along the direction of the in-plane current of the device to initialize it. Figure 2 The curves shown indicate that when an external magnetic field H of +300Oe or -300Oe is applied... x When the external magnetic field is zero, the spin-orbit torque (SOT) generated by the current can cause the magnetic moment of the free layer of an artificial antiferromagnetic structure with perpendicular magnetic anisotropy to be reversed. The polarity of the reversal loop is related to the direction of the external magnetic field. When the external magnetic field is zero, the SOT generated by the current can also reverse the magnetic moment of the free layer, and the polarity of the reversal loop is the same as that of the initial state. The reversal current density is greater than when an external magnetic field is present.

[0033] Figure 3 This is a schematic diagram of a magnetic random access memory (MRM) storage unit 200 according to an embodiment of the present invention, including... Figure 1 The artificial antiferromagnetic multilayer film structure shown is illustrated. Figure 3 In, with Figure 1 The same layers are indicated by the same reference numerals, and their repeated descriptions will be omitted here.

[0034] Reference Figure 3 Furthermore, a tunnel barrier layer 210, a reference layer 220, and a cap layer 230 may be formed on the free layer 130, thereby forming a magnetic tunnel junction (MTJ) structure. As previously mentioned, the magnetic moment of the free layer 130 can be flipped, while the magnetic moment of the reference layer 220 can remain unchanged, thus enabling parallel and antiparallel configurations, corresponding to low-resistivity and high-resistivity states, respectively.

[0035] The tunnel barrier layer 210 may be formed of a non-magnetic insulating material, examples of which include, but are not limited to, MgO, Al2O3, etc., and the thickness may be in the range of 1-4 nm. In some embodiments, the thickness of the tunnel barrier layer 210 may be greater than the thickness of the intermediate layer 120.

[0036] Reference layer 220 may include a fifth ferromagnetic layer (FM5) 222, a sixth ferromagnetic layer (FM6) 226, and a spacer layer 224 located between them. Each of the fifth and sixth ferromagnetic layers 222 and 226 may be formed of a ferromagnetic metal or alloy material, with a thickness ranging from 1 to 15 nm, and may have a perpendicular magnetization direction. The spacer layer 224 may be formed of a non-magnetic metal or alloy material, with a thickness ranging from 0.4 to 2.5 nm. It should be noted that the material and thickness of the spacer layer 224 may be selected such that it induces antiferromagnetic coupling between the fifth and sixth ferromagnetic layers 222 and 226, thereby making the magnetic moments of the fifth and sixth ferromagnetic layers 222 and 226 antiparallel to each other, forming an artificial antiferromagnetic structure. Structural examples of reference layer 220 include, but are not limited to, CoFeB / W / CoFeB, CoFeB / Ta / CoFeB, etc.

[0037] Because the reference layer 220 has an artificial antiferromagnetic structure, its net magnetic moment is very small, making it difficult to be flipped by an external magnetic field. During the operation of the MRAM memory cell 200, the magnetic moment of the reference layer 220 can remain unchanged. In some embodiments, an antiferromagnetic pinning layer, such as an IrMn layer, can also be formed on the reference layer 220 to pin the magnetic moment of the reference layer 220.

[0038] The cap layer 230 can be formed of a metal or alloy material with good conductivity and corrosion resistance, examples of which include, but are not limited to, W, Ta, Ru, Pt, Au, Ir, etc., and the thickness can be in the range of, for example, 5-10 nm, thereby protecting the underlying layer from the effects of oxidation and moisture corrosion. The cap layer 230 can also be used as a top electrode to apply a vertical read current to the MRAM memory cell 200.

[0039] Figure 4 Yes Figure 3 A schematic diagram illustrating read and write operations on storage unit 200. (See diagram for example.) Figure 3 As shown, the top layer of the memory cell 200, such as the cap layer 230, can be connected to the top electrode 301, and the bottom layer, such as the seed layer 102, can be connected to the bottom electrode 303. The opposite sides of the free layer 130 can be connected to intermediate electrodes 305 and 307, respectively, wherein the intermediate electrodes 305 and 307 are positioned in the direction of the in-plane bias magnetic field applied by the in-plane field coupling layer 110 to the free layer 130. During writing, as previously referred to... Figure 1 As described, an in-plane current is applied to the free layer 130 through intermediate electrodes 305 and 307. Depending on the direction of the in-plane current, the magnetic moment of the free layer 130 can be flipped between the vertically upward and downward directions, making it parallel or antiparallel relative to the reference layer 220. During reading, a vertical current flowing through the MTJ structure is applied through the top electrode 301 and bottom electrode 303, allowing the reading of the MTJ's resistance state and thus determining whether it is in a parallel or antiparallel state.

[0040] It should be noted that in the MTJ memory cell 200, each of the in-plane field coupling layer 110, the free layer 130, and the reference layer 220 has an artificial antiferromagnetic structure. Therefore, the MTJ memory cell 200 has a small net magnetic moment, which helps to improve device density. Simultaneously, the artificial antiferromagnetic structure improves the thermal stability of the magnetic device. Furthermore, the MTJ memory cell 200 with this structure can be flipped without an external magnetic field, greatly improving operational convenience.

[0041] Figure 5 This is a curve showing the relationship between magnetoresistance and external magnetic field, obtained by measuring the MRAM memory cell 200 under an external magnetic field. Figure 5 In one embodiment, the MRAM memory cell 200 has the following structure: W(1nm) / Co(2.2nm) / Ir(0.5nm) / W(0.4nm) / Co(2nm) / MgO(0.8nm) / CoFeB(1.3nm) / W(0.9nm) / CoFeB(0.9nm) / MgO(2nm) / CoFeB(1.3nm) / W(0.9nm) / CoFeB(0.9nm) / W(2nm) / Pt(5nm), where Co(2.2nm) / Ir(0.5nm) / W(0.4nm) / Co(2nm) is used as the in-plane field coupling layer 110, CoFeB(1.3nm) / W(0.9nm) / CoFeB(0.9nm) is used as the free layer 130, MgO(2nm) is used as the tunnel barrier layer 210, and CoFeB(1.3nm) / W(0.9nm) / CoFeB(0.9nm) is used as the reference layer 220. For example... Figure 5 As shown, the external magnetic field Hz is applied in the vertical direction, and the measured tunneling magnetoresistance (TMR) value of the MRAM memory cell 200 is in the range of 840Ω to 1200Ω, with a relative change of approximately 43%.

[0042] Figure 6 This is a curve showing the relationship between the magnetoresistive resistance and the write current of the MRAM memory cell 200. For example... Figure 6 As shown, when a stable external magnetic field Hx is applied along the current direction, the current I is written... write It allows for writing stored information, i.e., changing the TMR value of the device to switch between high-resistance and low-resistance states. Simultaneously, it allows for reading information by reading the current, i.e., reading the resistance state of the device.

[0043] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0044] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0045] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0046] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0047] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. An artificial antiferromagnetic multilayer film structure, comprising: The in-plane field coupling layer includes a first ferromagnetic layer and a second ferromagnetic layer formed of a ferromagnetic conductive material, and a first spacer layer located between the first ferromagnetic layer and the second ferromagnetic layer. The first spacer layer is formed of a non-magnetic conductive material and induces antiferromagnetic coupling between the first ferromagnetic layer and the second ferromagnetic layer to form an artificial antiferromagnetic structure. The free magnetic layer includes a third ferromagnetic layer and a fourth ferromagnetic layer formed of ferromagnetic conductive material, and a spin Hall effect layer located between the third ferromagnetic layer and the fourth ferromagnetic layer. The spin Hall effect layer is formed of a material with spin Hall effect and induces antiferromagnetic coupling between the third ferromagnetic layer and the fourth ferromagnetic layer to form an artificial antiferromagnetic structure. as well as An intermediate layer, located between the in-plane field coupling layer and the free magnetic layer, is formed of a non-magnetic material.

2. The artificial antiferromagnetic multilayer film structure as described in claim 1, wherein, The first and second ferromagnetic layers have in-plane magnetic anisotropy, and the third and fourth ferromagnetic layers have perpendicular magnetic anisotropy.

3. The artificial antiferromagnetic multilayer film structure as described in claim 1, wherein, The intermediate layer has a thickness in the range of 0.4-1.5 nm, which allows the in-plane field coupling layer to apply an interlayer coupling bias magnetic field to the free magnetic layer through the intermediate layer.

4. The artificial antiferromagnetic multilayer film structure as described in claim 1, wherein, The intermediate layer is formed of a non-magnetic insulating material.

5. The artificial antiferromagnetic multilayer film structure as described in claim 1, wherein, The third ferromagnetic layer in the free magnetic layer is closer to the in-plane field coupling layer than the fourth ferromagnetic layer, and the third ferromagnetic layer has a greater thickness than the fourth ferromagnetic layer.

6. A magnetic random access memory, comprising a plurality of memory cells, each memory cell comprising: The artificial antiferromagnetic multilayer film structure according to any one of claims 1-5; A tunnel barrier layer is formed on the free magnetic layer and is made of a non-magnetic insulating material; as well as A reference magnetic layer is formed on the tunnel barrier layer, comprising a fifth ferromagnetic layer and a sixth ferromagnetic layer formed of a ferromagnetically conductive material, and a second spacer layer located between the fifth and sixth ferromagnetic layers, the second spacer layer being formed of a non-magnetically conductive material and inducing antiferromagnetic coupling between the fifth and sixth ferromagnetic layers.

7. The magnetic random access memory as claimed in claim 6, wherein, The fifth and sixth ferromagnetic layers have perpendicular magnetic anisotropy.

8. The magnetic random access memory as claimed in claim 6, wherein, The free magnetic layer is configured to receive in-plane write current to flip the magnetic moment of the free magnetic layer, and the memory cell is configured to receive vertical read current to read the resistance state of the memory cell.

9. The magnetic random access memory as claimed in claim 8, wherein, The direction of the in-plane writing current is substantially parallel or antiparallel to the direction of the interlayer coupling bias magnetic field applied by the in-plane field coupling layer to the free magnetic layer.

10. The magnetic random access memory as claimed in claim 6, wherein, The thickness of the tunnel barrier layer is greater than the thickness of the intermediate layer.

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