Multi-resistance-state magnetic memory cell and magnetic memory

Abstract

The application provides a multi-resistance state magnetic storage unit and a magnetic storage. The multi-resistance state magnetic storage unit comprises two spin-orbit torque generating layers arranged separately, and a magnetic tunnel junction is arranged on each spin-orbit torque generating layer; free layers of the two magnetic tunnel junctions are close to the corresponding spin-orbit torque generating layers and are connected through a conductive connecting layer on the reference layer side. A port is led out from each of the first spin-orbit torque generating layer and the second spin-orbit torque generating layer. The multi-resistance state magnetic storage unit is a two-port structure, and multi-state storage is realized by combining STT and SOT.

Description

Technical Field

[0001] This invention relates to the field of magnetic memory technology, and in particular to a multi-resistivity magnetic memory cell and a magnetic memory. Background Technology

[0002] Spin-orbit torque magnetic memory (SOT-MRAM) is one of the more promising memory devices for the future because it is non-volatile, has fast erase and write speeds, and low power consumption.

[0003] SOT-MRAM memory cells consist of a magnetic tunnel junction (MTJ) and a spin-orbit torque generation layer. The MTJ comprises a free layer, a barrier layer, and a reference layer. The magnetization direction of the reference layer is fixed, while the magnetization direction of the free layer is variable. When the free layer and the reference layer are parallel, the MTJ exhibits a low-resistance state; when the free layer and the reference layer are antiparallel, the MTJ exhibits a high-resistance state. The spin-orbit torque generation layer is typically made of heavy metal. When current flows through the heavy metal, the SOT (spin-orbit torque) effect deflects the magnetic moment of the free layer. With the assistance of an external magnetic field, a deterministic reversal of the free layer's magnetic moment can be achieved.

[0004] To improve storage density, polymorphic MRAM is a viable solution. However, current polymorphic MRAM based on the STT (spin-transfer torque) effect requires external magnetic field assistance, thermal assistance, and other methods for writing, which is complex and involves high current. Polymorphic MRAM based on the SOT (spin-orbit torque) effect still uses a three-port structure, which reduces the integration density of the memory and increases the cost. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a multi-resistivity magnetic storage unit and a magnetic memory, employing a dual-port structure and utilizing STT combined with SOT to achieve multi-state storage, reduce current, and improve integration.

[0006] In a first aspect, the present invention provides a multi-resistivity magnetic memory cell, comprising:

[0007] A first spin-orbit moment generation layer and a second spin-orbit moment generation layer are separately arranged on the same plane;

[0008] A first magnetic tunnel junction is disposed on one side surface of the first spin-orbit moment generating layer, including a first free layer, a first barrier layer and a first reference layer stacked together, with the first free layer close to the first spin-orbit moment generating layer;

[0009] The second magnetic tunnel junction is disposed on one side surface of the second spin-orbit moment generating layer and is kept on the same side as the first magnetic tunnel junction. It includes a stacked second free layer, a second barrier layer and a second reference layer. The second free layer is close to the second spin-orbit moment generating layer.

[0010] A conductive connection layer is disposed close to the first reference layer and the second reference layer, for connecting the first magnetic tunnel junction and the second magnetic tunnel junction from the reference layer side;

[0011] In addition, a first port leading out from one end of the first spin orbital moment generating layer and a second port leading out from one end of the second spin orbital moment generating layer are provided for connecting an external voltage to form a current flowing sequentially through the first spin orbital moment generating layer, the first magnetic tunnel junction, the connecting layer, the second magnetic tunnel junction and the second spin orbital moment generating layer.

[0012] Optionally, the first free layer, the first reference layer, the second reference layer, and the second free layer are in-plane magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same.

[0013] Optionally, the first free layer, the first reference layer, the second reference layer, and the second free layer are vertically magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same;

[0014] Correspondingly, the multi-resistivity magnetic memory cell also includes:

[0015] A magnetic bias layer is located on the side of the connection layer away from the first magnetic tunnel junction and the second magnetic tunnel junction.

[0016] Optionally, the first free layer, the first reference layer, the second reference layer, and the second free layer are vertically magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same;

[0017] Correspondingly, the multi-resistivity magnetic memory cell also includes:

[0018] A first magnetic bias layer and a second magnetic bias layer are separately disposed, wherein the first magnetic bias layer is located on the side of the first spin-orbit moment generating layer away from the first free layer, and the second magnetic bias layer is located on the side of the second spin-orbit moment generating layer away from the second free layer.

[0019] Optionally, the first magnetic tunnel junction and the second magnetic tunnel junction may have the same or different cross-sectional dimensions.

[0020] Secondly, the present invention provides a multi-resistivity magnetic memory cell, comprising: a first spin-orbit moment generation layer, a first magnetic tunnel junction, a second magnetic tunnel junction, and a second spin-orbit moment generation layer stacked vertically, wherein...

[0021] The first magnetic tunnel junction includes a first free layer, a first barrier layer and a first reference layer stacked sequentially, with the first free layer close to the first spin-orbit moment generating layer;

[0022] The second magnetic tunnel junction includes a second reference layer, a second barrier layer, and a second free layer stacked sequentially, with the second reference layer close to the first reference layer and the second free layer close to the second spin-orbit moment generating layer.

[0023] In addition, a first port leading out from one end of the first spin orbital moment generating layer and a second port leading out from one end of the second spin orbital moment generating layer are provided for connecting an external voltage to form a current flowing sequentially through the first spin orbital moment generating layer, the first magnetic tunnel junction, the second magnetic tunnel junction and the second spin orbital moment generating layer.

[0024] Optionally, the first free layer, the first reference layer, the second reference layer, and the second free layer are in-plane magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same.

[0025] Optionally, the first free layer, the first reference layer, the second reference layer, and the second free layer are vertically magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same;

[0026] Correspondingly, the multi-resistivity magnetic memory cell also includes:

[0027] The magnetic bias layer is located on the side of the first spin-orbit moment generating layer away from the first free layer, or on the side of the second spin-orbit moment generating layer away from the second free layer.

[0028] Optionally, if the first reference layer and the second reference layer are adjacent, the first reference layer and the second reference layer are merged into a common reference layer, which serves as the reference layer for both the first magnetic tunnel junction and the second magnetic tunnel junction.

[0029] Optionally, the positions of the first port relative to the first spin-orbit moment generating layer and the second port relative to the second spin-orbit moment generating layer may be on the same side or on different sides.

[0030] Thirdly, the present invention provides a magnetic memory, including a multi-resistivity magnetic memory cell as described in the first or second aspect.

[0031] This invention provides a multi-resistivity memory cell based on spin-orbit moments, employing a dual magnetic tunnel junction structure. The magnetization flipping of the free layers in both magnetic tunnel junctions is dominated by spin-orbit moments, with spin-transfer torque also participating. Compared to multi-state STT-MRAM, this reduces the critical flip current, lowers power consumption, increases erase / write cycles, and reduces operational complexity. Furthermore, the multi-resistivity memory cell of this invention uses a dual-terminal structure, which, compared to three-terminal multi-state SOT-MRAM, reduces the use of select transistors, source lines, word lines, bit lines, etc., simplifying the array structure and improving integration density. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a multi-resistivity magnetic memory cell according to an embodiment of the present invention;

[0033] Figure 2 for Figure 1 The diagram shows the interaction between SOT and STT in a multi-resistivity magnetic memory cell.

[0034] Figure 3 This is a schematic diagram of the structure of a multi-resistivity magnetic memory cell according to an embodiment of the present invention;

[0035] Figure 4 This is a schematic diagram of the structure of a multi-resistivity magnetic memory cell according to an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the structure of a multi-resistivity magnetic memory cell according to an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram of the structure of a multi-resistivity magnetic memory cell according to an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the structure of a multi-resistivity magnetic memory cell according to an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the structure of a multi-resistivity magnetic memory cell according to an embodiment of the present invention;

[0040] Figure 9 This is a schematic diagram of the structure of a multi-resistivity magnetic storage cell according to an embodiment of the present invention. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0043] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0044] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0045] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0046] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0047] Example 1

[0048] Figure 1 This is a schematic diagram of the structure of a multi-resistivity magnetic memory cell provided in an embodiment of the present invention. Figure 1As shown, the multi-resistivity magnetic memory cell 10 includes a first spin-orbit moment generation layer 101, a second spin-orbit moment generation layer 102, a first magnetic tunnel junction 103, a second magnetic tunnel junction 104, and a connecting layer 105. The first spin-orbit moment generation layer 101 and the second spin-orbit moment generation layer 102 are separately disposed, typically formed by etching a layer of heavy metal, and are therefore horizontally arranged on a single plane. The first magnetic tunnel junction 103 is disposed on the upper surface of the first spin-orbit moment generation layer 101. The first magnetic tunnel junction 103 includes a stacked first free layer 1031, a first barrier layer 1032, and a first reference layer 1033, wherein the first free layer 1031 is close to the first spin-orbit moment generation layer 101. The second magnetic tunnel junction 104 is disposed on the upper surface of the second spin-orbit moment generating layer 102, i.e., on the same side as the first magnetic tunnel junction. The second magnetic tunnel junction 104 includes a stacked second free layer 1041, a second barrier layer 1042, and a second reference layer 1043, with the second free layer 1041 close to the second spin-orbit moment generating layer 102. The connecting layer 105 is disposed close to the first reference layer 1033 and the second reference layer 1043, and has electrical conductivity, generally using a conductive metal, such as Cu, Al, Ta, or their alloys. The connecting layer 105 is used to connect the first magnetic tunnel junction 103 and the second magnetic tunnel junction 104 from the reference layer side, generally forming a current loop.

[0049] Additionally, a first port D1 is drawn from the first spin-orbit moment generating layer 101, and a second port D2 is drawn from the second spin-orbit moment generating layer 102. The first port D1 and the second port D2 are used to connect an external voltage to form a current that flows sequentially through the first spin-orbit moment generating layer 101, the first magnetic tunnel junction 103, the connecting layer 105, the second magnetic tunnel junction 104, and the second spin-orbit moment generating layer 102. This current is used to reverse the magnetization direction of the first free layer 1031 and the second free layer 1041.

[0050] It should be noted that the direction of the current must meet the following conditions: the current direction in the first spin orbit moment generating layer 101 is perpendicular to the magnetization direction of the first free layer 1031 and the first reference layer 1033, and the current direction in the second spin orbit moment generating layer 102 is perpendicular to the magnetization direction of the second free layer 1041 and the second reference layer 1043.

[0051] As one implementation method, such as Figure 1 As shown, in this embodiment, the free layer and reference layer of the two magnetic tunnel junctions are in-plane magnetized. Specifically, the magnetization direction of the first reference layer 1033 is perpendicular to the paper and outwards, and the magnetization direction of the first free layer 1031 is perpendicular to the paper and outwards or inwards. The magnetization direction of the second reference layer 1043 is perpendicular to the paper and outwards, and the magnetization direction of the second free layer 1041 is perpendicular to the paper and outwards or inwards.

[0052] For Figure 1 the multi-resistive magnetic storage cell shown, the principle of realizing multiple resistive states is introduced in detail as follows. Refer to Figure 2 , the current flows through the first spin-orbit torque generation layer 101, the first magnetic tunnel junction 103, the connection layer 105, the second magnetic tunnel junction 104, and the second spin-orbit torque generation layer 102 in sequence. The current direction in the first spin-orbit torque generation layer 101 is opposite to the current direction in the second spin-orbit torque generation layer 102. Figure 2 shows a schematic diagram of the functions of spin-orbit torque (SOT) and spin-transfer torque (STT) in two magnetic tunnel junctions.

[0053] When the first spin-orbit torque generation layer 101 and the second spin-orbit torque generation layer 102 use materials with a negative spin Hall angle (such as Ta, W, etc.), the current flows into the first spin-orbit torque generation layer 101, passes through the first magnetic tunnel junction, the connection layer, and the second magnetic tunnel junction, and flows out from the second spin-orbit torque generation layer 102. The directions of the electrons are opposite.

[0054] At the interface of the bottom SOT of the first magnetic tunnel junction (MTJ1), the electron polarization direction is perpendicular to the paper and inward. The STT effect is that the polarization direction of the electrons passing through the first reference layer is consistent with the magnetization direction of the first reference layer, and is perpendicular to the paper and outward in the first free layer. The SOT and STT compete with each other (the acting force is expressed as SOT-STT). The critical current for flipping the first free layer of the first magnetic tunnel junction is denoted as I1.

[0055] At the interface of the bottom SOT of the second magnetic tunnel junction (MTJ2), the electron polarization direction is perpendicular to the paper and inward. The STT effect is that only electrons with the same magnetization direction as the second reference layer can pass through the second reference layer. Therefore, electrons with the opposite magnetization direction to the second reference layer (perpendicular to the paper and inward) accumulate and act in the second free layer. The SOT and STT are superimposed on each other (the acting force is expressed as SOT+STT). The critical current for flipping the second free layer of the second magnetic tunnel junction is denoted as I2. Obviously, I2 < I1. That is, the two magnetic tunnel junctions have different flipping threshold currents.

[0056] When the applied current I < I2, neither of the two MTJs flips;

[0057] When I2 ≤ I < I1, MTJ2 flips and MTJ1 does not flip;

[0058] When I ≥ I1, both MTJs flip.

[0059] Therefore, by applying different currents, different magnetization states of the two MTJs can be achieved, corresponding to different resistive states. In this embodiment, there are three resistive states.

[0060] It should also be noted that, generally, the stacked structures on both sides are symmetrical, which facilitates manufacturing processes. The cross-sectional dimensions of the two MTJs can be the same or different. The shapes of the two MTJs are also not limited; they can be circular, elliptical, rectangular, rhomboid, or triangular. By changing the shape and size of the two MTJs, the resistive states of the memory cells can be increased.

[0061] As another implementation, the magnetization direction of the two magnetic tunnel junctions can also be perpendicular magnetization. However, perpendicularly magnetized MTJ structures require an external bias magnetic field under certain conditions. (Compared to...) Figure 1 A magnetic bias layer needs to be added. The magnetic bias layer can be placed on top of the connecting layer or at the bottom of the spin orbit moment generation layer.

[0062] refer to Figure 3 The multi-resistivity magnetic memory cell 20 includes a first spin-orbit moment generation layer 201, a second spin-orbit moment generation layer 202, a first magnetic tunnel junction 203, a second magnetic tunnel junction 204, a connecting layer 205, and a magnetic bias layer 206. The first magnetic tunnel junction 203 includes a stacked first free layer 2031, a first barrier layer 2032, and a first reference layer 2033. The second magnetic tunnel junction 204 includes a stacked second free layer 2041, a second barrier layer 2042, and a second reference layer 2043. The first free layer, the first reference layer, the second free layer, and the second reference layer are all vertically magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same. Compared to... Figure 1 The difference in the multi-resistivity magnetic storage cell 10 shown is that the magnetization directions of the free layer and the reference layer of the two magnetic tunnel junctions are perpendicular, and a magnetic bias layer 206 is provided above the connection layer 205. The magnetic bias layer 206 is used to provide an external bias magnetic field for the magnetization reversal of the two magnetic tunnel junctions.

[0063] As another implementation method, refer to Figure 4 The multi-resistivity magnetic memory cell 30 includes a first spin-orbit moment generation layer 301, a second spin-orbit moment generation layer 302, a first magnetic tunnel junction 303, a second magnetic tunnel junction 304, a connecting layer 305, a first magnetic bias layer 306, and a second magnetic bias layer 307. The first magnetic tunnel junction 303 includes a stacked first free layer 3031, a first barrier layer 3032, and a first reference layer 3033. The second magnetic tunnel junction 304 includes a stacked second free layer 3041, a second barrier layer 3042, and a second reference layer 3043. The first free layer, the first reference layer, the second free layer, and the second reference layer are all vertically magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same. Compared to... Figure 1The difference in the multi-resistivity magnetic storage cell 10 shown is that the magnetization directions of the free layer and the reference layer of the two magnetic tunnel junctions are perpendicular. A first magnetic bias layer 306 is provided below the first spin orbital moment generating layer 301, and a second magnetic bias layer 307 is provided below the second spin orbital moment generating layer 302. The two magnetic bias layers 306 and 307 are set separately to provide the external bias magnetic field for the corresponding magnetic tunnel junction magnetization reversal.

[0064] In addition, it is conceivable that the above-mentioned storage unit structures can be extended outwards indefinitely, forming a shape with varying heights (similar to the Great Wall).

[0065] The multi-resistivity magnetic storage cell provided in this embodiment of the invention is a dual-port structure. Two spin orbital moment generating layers are respectively connected to one port, and different currents are passed through them. The two MTJs are subjected to different SOT and STT effects, and the two MTJs exhibit different resistive states, thus realizing multi-resistivity storage.

[0066] Example 2

[0067] On the other hand, embodiments of the present invention also provide a multi-resistivity magnetic memory cell, such as... Figure 5 As shown, the multi-resistivity magnetic storage cell 50 includes a first spin-orbit moment generation layer 501, a first magnetic tunnel junction 502, a second magnetic tunnel junction 503, and a second spin-orbit moment generation layer 504 stacked vertically from bottom to top. The first magnetic tunnel junction 502 includes a first free layer 5021, a first barrier layer 5022, and a first reference layer 5023 stacked sequentially, with the first free layer 5021 close to the first spin-orbit moment generation layer 501. The second magnetic tunnel junction 503 includes a second reference layer 5033, a second barrier layer 5032, and a second free layer 5031 stacked sequentially, with the second reference layer 5033 close to the first reference layer 5023 and the second free layer 5031 close to the second spin-orbit moment generation layer 504.

[0068] Additionally, a first port D1 is drawn from the first spin-orbit moment generating layer 501, and a second port D2 is drawn from the second spin-orbit moment generating layer 504. The first port D1 and the second port D2 are used to connect an external voltage to form a current that flows sequentially through the first spin-orbit moment generating layer 501, the first magnetic tunnel junction 502, the second magnetic tunnel junction 503, and the second spin-orbit moment generating layer 504. This current is used to reverse the magnetization direction of the first free layer 5021 and the second free layer 5031.

[0069] It should be noted that the direction of the current needs to meet the conditions: the direction of the current in the first spin-orbit torque generation layer 501 is perpendicular to the magnetization directions of the first free layer 5021 and the first reference layer 5023, and the direction of the current in the second spin-orbit torque generation layer 504 is perpendicular to the magnetization directions of the second free layer 5031 and the second reference layer 5033.

[0070] As an implementation manner, as Figure 5 shown, in this embodiment, the free layers and the reference layers of the two magnetic tunnel junctions are magnetized in the plane. Specifically, the magnetization direction of the first reference layer 5023 is perpendicular to the paper surface and outward, and the magnetization direction of the first free layer 5021 is perpendicular to the paper surface and outward or inward. The magnetization direction of the second reference layer 5033 is perpendicular to the paper surface and outward, and the magnetization direction of the second free layer 5031 is perpendicular to the paper surface and outward or inward. For the directions of the two ports, in this embodiment, the first port D1 is located on the left side of the first spin-orbit torque generation layer 501, and the second port D2 is located on the left side of the second spin-orbit torque generation layer 504.

[0071] For Figure 5 the multi-resistance state magnetic storage cell 50 shown, the principle of the multi-resistance state magnetic storage cell 50 to achieve the multi-resistance state is the same as that of the multi-resistance state storage cell 10 to achieve the multi-resistance state. The current flows in from the left side of the first spin-orbit torque generation layer 501, passes through the first magnetic tunnel junction 502 and the second magnetic tunnel junction 503, and flows out from the left side of the second spin-orbit torque generation layer 504.

[0072] The bottom SOT of the first magnetic tunnel junction (MTJ1) acts at the interface, the electron polarization direction is perpendicular to the paper surface and inward, the STT effect is that the polarization direction of the electrons passing through the first reference layer is the same as the magnetization direction of the first reference layer, and it is perpendicular to the paper surface and outward in the first free layer. SOT and STT compete with each other (the acting force is expressed as SOT - STT), and the critical current for flipping the first free layer of the first magnetic tunnel junction is denoted as I1.

[0073] The bottom SOT of the second magnetic tunnel junction (MTJ2) acts at the interface, the electron polarization direction is perpendicular to the paper surface and inward, the STT effect is that only the electrons with the same magnetization direction as the second reference layer can pass through the second reference layer. Therefore, the electrons with the magnetization direction opposite to the second reference layer (perpendicular to the paper surface and inward) accumulate and act in the second free layer. SOT and STT are superimposed on each other (the acting force is expressed as SOT + STT), and the critical current for flipping the second free layer of the second magnetic tunnel junction is denoted as I2. Obviously, I2 < I1. That is, the two magnetic tunnel junctions have different flipping threshold currents.

[0074] When the applied current I < I2, neither of the two MTJs flips;

[0075] When I2 ≤ I < I1, MTJ2 flips and MTJ1 does not flip;

[0076] When I≥I1, both MTJs are flipped.

[0077] Therefore, by applying different currents, two different magnetization states of the MTJ can be achieved, corresponding to different resistance states. This embodiment has three resistance states. Furthermore, this multi-resistance-state magnetic storage unit 50 is superior to... Figure 1 The multi-resistivity magnetic storage cell 10 shown has increased integration due to its vertical stacking structure, thereby increasing storage density.

[0078] As another implementation, the magnetization direction of the two magnetic tunnel junctions can also be perpendicular magnetization. However, perpendicularly magnetized MTJ structures require an external bias magnetic field under certain conditions. (Compared to...) Figure 5 A magnetic bias layer needs to be added. The magnetic bias layer can be located below the first spin-orbit moment generating layer 501, or above the second spin-orbit moment generating layer 504.

[0079] Figure 6 A schematic diagram of a structure in which a magnetic bias layer 505 is added above the second spin orbital moment generating layer 504 is shown. Figure 6 The multi-resistivity magnetic storage cell has two magnetic tunnel junctions, where the free layer and reference layer are both vertically magnetized. A similar approach can be taken when a magnetic bias layer is added below the first spin-orbit moment generation layer.

[0080] To further explain, such as Figure 7 As shown, since the first magnetic tunnel junction and the second magnetic tunnel junction are arranged adjacent to each other, and the two reference layers are close to each other, if no other stacked structure is required between the two reference layers, then the two reference layers can be merged into a common reference layer, which serves as the reference layer for both the first magnetic tunnel junction and the second magnetic tunnel junction. Figure 7 It shows that Figure 5 The stacked structure after the first and second reference layers are merged into a single reference layer.

[0081] It should also be noted that the port orientations of the first and second ports determine whether the SOT and STT at the interface are superimposed or competing. Therefore, changing the port orientations of the first and second ports, i.e., changing the current direction, will alter the magnetization reversal characteristics of the two magnetic tunnel junctions. Setting the positions of the two ports allows control over the magnitude of the critical reversal current of the two MTJs.

[0082] For example, such as Figure 8As shown, current flows in from the left side of the first spin-orbit moment generation layer 501, passes through the first magnetic tunnel junction 502 and the second magnetic tunnel junction 503, and flows out from the right side of the second spin-orbit moment generation layer 504. The STT and SOT forces acting on the first magnetic tunnel junction 502 are SOT-STT, and the STT and SOT forces acting on the second magnetic tunnel junction 503 are SOT-STT.

[0083] like Figure 9 As shown, current flows in from the right side of the first spin-orbit moment generation layer 501, passes through the first magnetic tunnel junction 502 and the second magnetic tunnel junction 503, and flows out from the left side of the second spin-orbit moment generation layer 504. The STT and SOT forces acting on the first magnetic tunnel junction 502 are SOT+STT, and the STT and SOT forces acting on the second magnetic tunnel junction 503 are SOT+STT.

[0084] Although the superposition or competition relationship between SOT and STT is the same for both magnetic tunnel junctions in the two embodiments above, the critical switching current magnitudes of the two MTJs will differ as long as the electron transmittance and reflectance of the reference layer are different. If the operating window is small, the free layer and barrier layer of the two MTJs can be made of different materials, thicknesses, and sizes, or the reference layer can be structurally asymmetric, or the materials or thicknesses of the first and second spin-orbit moment generating layers can be adjusted to change the strength of the SOT effect.

[0085] The multi-resistivity magnetic storage cell provided in this embodiment of the invention is a dual-port structure. Two spin orbital moment generating layers are respectively connected to one port, and different currents are passed through them. The two MTJs are subjected to different SOT and STT effects, and the two MTJs exhibit different resistive states, thus realizing multi-resistivity storage.

[0086] In addition, embodiments of the present invention also provide a magnetic memory, including the multi-resistivity magnetic memory cell provided in the above embodiments.

[0087] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-resistivity magnetic storage cell, characterized in that, include: A first spin-orbit moment generation layer and a second spin-orbit moment generation layer are separately arranged on the same plane; A first magnetic tunnel junction is disposed on one side surface of the first spin-orbit moment generating layer, including a first free layer, a first barrier layer and a first reference layer stacked together, with the first free layer close to the first spin-orbit moment generating layer; The second magnetic tunnel junction is disposed on one side surface of the second spin-orbit moment generating layer and is kept on the same side as the first magnetic tunnel junction. It includes a stacked second free layer, a second barrier layer and a second reference layer. The second free layer is close to the second spin-orbit moment generating layer. A conductive connection layer is disposed close to the first reference layer and the second reference layer, for connecting the first magnetic tunnel junction and the second magnetic tunnel junction from the reference layer side; In addition, a first port leading out from one end of the first spin orbit moment generating layer and a second port leading out from one end of the second spin orbit moment generating layer, the first port and the second port are used to connect an external voltage so as to form a current flowing sequentially through the first spin orbit moment generating layer, the first magnetic tunnel junction, the connecting layer, the second magnetic tunnel junction and the second spin orbit moment generating layer; The multi-configuration magnetic storage cell can realize three resistance states, corresponding to the resistance state when I < I2, the resistance state when I2 ≤ I < I1, and the resistance state when I ≥ I1, respectively, where I represents the applied current, I1 represents the critical current for the first free layer of the first magnetic tunnel junction to flip, I2 represents the critical current for the second free layer of the second magnetic tunnel junction to flip, and I2 represents the critical current for the second free layer of the second magnetic tunnel junction to flip. <I1。 2. The multi-resistivity magnetic storage cell according to claim 1, characterized in that, The first free layer, the first reference layer, the second reference layer, and the second free layer are in-plane magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same.

3. The multi-resistivity magnetic storage cell according to claim 1, characterized in that, The first free layer, the first reference layer, the second reference layer, and the second free layer are vertically magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same. Correspondingly, the multi-resistivity magnetic memory cell also includes: A magnetic bias layer is located on the side of the connection layer away from the first magnetic tunnel junction and the second magnetic tunnel junction.

4. The multi-resistivity magnetic storage cell according to claim 1, characterized in that, The first free layer, the first reference layer, the second reference layer, and the second free layer are vertically magnetized, and the magnetization directions of the first reference layer and the second reference layer are the same. Correspondingly, the multi-resistivity magnetic memory cell also includes: A first magnetic bias layer and a second magnetic bias layer are separately disposed, wherein the first magnetic bias layer is located on the side of the first spin-orbit moment generating layer away from the first free layer, and the second magnetic bias layer is located on the side of the second spin-orbit moment generating layer away from the second free layer.

5. The multi-resistivity magnetic storage cell according to any one of claims 1 to 4, characterized in that, The first magnetic tunnel junction and the second magnetic tunnel junction have the same or different cross-sectional dimensions.

6. A magnetic storage device, characterized in that, The magnetic memory includes a multi-resistivity magnetic memory cell as described in any one of claims 1 to 5.

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