A magnetic memory based on magnetic spin writing and a reading and writing method

Abstract

The application provides a magnetic memory based on magnon writing and a reading and writing method, which comprises a magnetic insulating layer, a non-magnetic spacer layer, a free layer, a barrier layer and a reference layer which are stacked in sequence; the magnetic insulating layer is used for generating and propagating magnons along an in-plane direction in response to external excitation, and a spin accumulation region is formed at the interface between the magnetic insulating layer and the non-magnetic spacer layer, and is used for generating a spin current which is perpendicular to the interface; the free layer has magnetism, is used for receiving the spin current and generating a torque for flipping the magnetization direction of the free layer; the barrier layer is used for allowing tunneling current to pass through and preventing the spin current from propagating to the reference layer; the reference layer has magnetism, and a magnetic moment thereof is pinned and forms a parallel or anti-parallel state with the magnetic moment of the free layer, and different storage state marks are corresponded, respectively; the magnetic memory uses magnons in a ferromagnetic insulator as a writing excitation source, relies on the propagation of the magnons in the insulator and spin current injection to not generate electric current flow, and eliminates Joule heat, so that the writing power consumption of the magnetic memory is reduced.

Description

Technical Field

[0001] This invention relates to the field of identification, and more particularly to a magnetic memory based on magnetic writing and a reading / writing method thereon. Background Technology

[0002] Currently, magnetic memory based on MRAM has formed a complete technology echelon from mature commercialization to cutting-edge exploration. Among them, the mainstream mass-produced STT-MRAM has achieved large-scale application in automotive, industrial and consumer electronics fields. With its non-volatility, nanosecond-level high-speed read and write, and ultra-high erasure and write resistance, it is regarded as a strong competitor to replace NOR Flash and embedded SRAM. The advanced SOT-MRAM has become a research hotspot with its faster write speed, lower write power consumption and near-infinite erasure and write life.

[0003] Current MRAM technology still suffers from excessive power consumption during writing. On the one hand, traditional writing methods rely on direct writing using magnetic fields or current. The current flowing through the conductor inevitably generates Joule heat, resulting in energy loss. On the other hand, in order to ensure the reliability and thermal stability of stored information, the storage medium needs to have high magnetic anisotropy. High magnetic anisotropy will further increase the writing current, thus increasing the power consumption of the magnetic memory during writing. Summary of the Invention

[0004] In view of this, the present invention proposes a magnetic memory based on magnetic particle writing and a read / write method. It uses magnetic particles in a ferromagnetic insulator as the writing excitation source. Relying on the propagation of magnetic particles in the insulator and the injection of spin current, no charge flow is generated, thereby eliminating Joule heating. Furthermore, by setting a non-magnetic spacer layer to break the direct exchange coupling between the magnetic insulating layer and the free layer, the coercivity of the free layer can be improved without increasing the writing power consumption, thus reducing the writing power consumption of the magnetic memory.

[0005] The technical solution of the present invention is implemented as follows: In a first aspect, the present invention provides a magnetic memory based on magnetic writing, comprising a magnetic insulating layer, a non-magnetic spacer layer, a free layer, a barrier layer and a reference layer; A non-magnetic spacer layer is disposed on one side of the magnetic insulating layer. The magnetic insulating layer is used to generate and propagate magnetic particles in the in-plane direction in response to external excitation. A spin accumulation region is formed at the interface between the magnetic insulating layer and the non-magnetic spacer layer to generate a spin flow perpendicular to the interface. A free layer is disposed on the side of the non-magnetic spacer layer away from the magnetic insulating layer. The free layer is magnetic and is used to receive spin current and generate torque for reversing its magnetization direction. The barrier layer is placed on the side of the free layer away from the non-magnetic spacer layer to allow tunneling current to pass through and prevent spin current from propagating to the reference layer. The reference layer is disposed on the side of the barrier layer away from the free layer. The reference layer is magnetic and the magnetic moment is pinned to provide a fixed reference magnetic moment direction. It is parallel or antiparallel to the magnetic rectangle of the free layer, corresponding to the storage state identifier 0 or 1, respectively.

[0006] Based on the above technical solutions, preferably, a first electrode layer is also included. The first electrode layer is disposed on the side of the reference layer away from the barrier layer and is used to pass a read current during the read operation. The read current is less than the flip current of the free layer.

[0007] Based on the above technical solutions, preferably, it also includes an excitation source, which is disposed on the magnetic insulating layer and is used to excite the magnetic insulating layer to generate magnets when an in-plane current is passed through it. The direction of the current passed through the excitation source is in-plane and is parallel or antiparallel to the magnetic moment direction of the free layer.

[0008] Based on the above technical solutions, preferably, the material of the magnetic insulating layer is a magnetic insulator, including at least one of YIG, TmIG, BFO, α-Fe2O3, gadolinium gallium garnet, gadoferroic garnet or Fe5GeTe2.

[0009] Based on the above technical solutions, preferably, the thickness of the magnetic insulating layer is 0.5nm to 50nm.

[0010] Based on the above technical solutions, preferably, the materials of the free layer and the reference layer are ferromagnetic metals, including at least one of Co, Fe, Ni and their alloys CoFeB, CoFe or NiFe, and the thickness of the free layer is 0.5 nm to 10 nm.

[0011] Based on the above technical solutions, preferably, the material of the barrier layer is a non-magnetic insulating material, including at least one of MgO or Al2O3, and the thickness of the barrier layer is 0.8nm to 2nm.

[0012] Based on the above technical solutions, preferably, the material of the non-magnetic spacer layer is a metal with a long spin diffusion length, including at least one of Cu, Ag or Au.

[0013] Based on the above technical solutions, preferably, the material of the excitation source is a heavy metal or topological insulator with strong spin-orbit coupling, including Pt, Ta, Pd, Ir, W, Pb, Hf or their alloys, and at least one of Bi2Se3 or Bi2Te3.

[0014] Secondly, the present invention also provides a read / write method for a magnetic memory based on magnetic field writing, which is implemented using a magnetic memory based on magnetic field writing and includes the following steps: S1, during the write operation, a magneton is generated in the magnetic insulating layer by passing an in-plane current through the excitation source. S2, the magnetic particle propagates in the in-plane direction within the magnetic insulating layer and reaches the interface between the magnetic insulating layer and the non-magnetic spacer layer. S3 generates spin accumulation at the interface through the spin pumping effect, forming a spin flow perpendicular to the interface; S4, the spin flow is injected into the free layer through the non-magnetic spacer layer, and the barrier layer prevents the spin flow from continuing to propagate to the reference layer, thus confining the spin flow within the free layer; S5, the spin flow generates a magneton torque in the free layer, which reverses the magnetization direction of the free layer; S6, depending on whether the magnetic moments of the free layer and the reference layer are parallel or antiparallel, corresponds to the storage state identifier 0 or 1 respectively; S7. During the read operation, a read current is passed between the first electrode layer and the non-magnetic spacer layer. The read current passes through the reference layer, the barrier layer, the free layer and the non-magnetic spacer layer in sequence. Based on the low resistance state or high resistance state corresponding to the parallel or antiparallel magnetic moments of the reference layer and the free layer, the corresponding storage state flag 0 or 1 is read by detecting the low resistance state or high resistance state.

[0015] The magnetic memory and read / write method based on magnetic particle writing of the present invention have the following advantages over the prior art: (1) By utilizing the propagation of magnetic particles in ferromagnetic insulators and the spin pumping effect to generate spin current, there is no charge flow during the writing process, eliminating Joule heat loss and reducing the writing power consumption of magnetic memory. (2) By setting a non-magnetic spacer layer, the direct exchange coupling between the magnetic insulating layer and the free layer is broken, the coupling resistance is eliminated, and the free layer is easier to flip. At the same time, the indirect exchange effect introduced by the non-magnetic spacer layer can improve the coercivity of the free layer and enhance the stability of data storage. (3) By effectively preventing the spin flow from propagating to the reference layer during writing through the barrier layer, the spin flow energy is concentrated in the free layer, which improves the flipping efficiency. The read operation adopts an independent path and the read current is less than the free layer flipping current, which avoids erroneous writing during the read process and realizes non-destructive reading. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1This is a structural architecture diagram of the magnetic memory based on magnetic write according to the present invention; Figure 2 This is a schematic diagram of information writing in the magnetic memory based on magnetic writing according to the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1-2 As shown, a magnetic memory based on magnetic writing according to the present invention includes a magnetic insulating layer 1, a non-magnetic spacer layer 2, a free layer 3, a barrier layer 4 and a reference layer 5. In this embodiment, the material of the magnetic insulating layer 1 is a magnetic insulator, including at least one of YIG, TmIG, BFO, α-Fe2O3, gadolinium gallium garnet, gadolinium iron garnet, or Fe5GeTe2, and the thickness of the magnetic insulating layer 1 is 0.5 nm to 50 nm. In this embodiment, the thickness of the magnetic insulating layer 1 is preferably 15 nm.

[0020] It should be noted that magnetic insulators are materials with long-range magnetic order and strong exchange coupling. Spin can propagate through the interaction between adjacent magnetic moments. Since they are insulators, there is no loss due to charge flow, and they can transmit spin over long distances. Examples of magnetic insulators include, but are not limited to, YIG, TmIG, BFO, α-Fe2O3, gadolinium gallium garnet, gadolinium iron garnet or similar ferromagnetic, subferromagnetic or antiferromagnetic insulators, as well as two-dimensional van der Waals materials such as Fe5GeTe2.

[0021] To obtain a high-quality lattice structure and a low magnetic wave damping coefficient, the magnetic insulating layer 1 can be prepared by epitaxial growth. For example, YIG thin films can be grown on gadolinium gallium garnet (GGG) substrates with matched lattice constants by liquid phase epitaxy or magnetron sputtering. High-quality epitaxial films can significantly reduce crystal defects and impurity scattering, which is beneficial for long-distance propagation of magnetic waves and thus improves writing efficiency.

[0022] In addition, to ensure that the interface between the magnetic insulating layer 1 and the non-magnetic spacer layer 2 has an efficient spin pumping effect, the surface of the magnetic insulating layer 1 can be argon ion etching or annealing before depositing the non-magnetic spacer layer 2 to obtain an atomically smooth and contamination-free clean interface.

[0023] This embodiment also includes an excitation source 7, which is disposed on the magnetic insulating layer 1 and is used to excite the magnetic insulating layer 1 to generate magnetons when an in-plane current is applied. The material of the excitation source 7 is a heavy metal or topological insulator with strong spin-orbit coupling, including Pt, Ta, Pd, Ir, W, Pb, Hf or alloys thereof, and at least one of Bi2Se3 or Bi2Te3.

[0024] Specifically, in this embodiment, the material of the excitation source 7 is preferably Pt with a thickness of 5-10 nm. It is deposited on the magnetic insulating layer 1 by magnetron sputtering and formed into a strip electrode by photolithography and ion beam etching. The long side of the strip electrode is perpendicular to the direction of magnetic particle propagation to maximize the efficiency of magnetic particle generation and directional propagation.

[0025] like Figure 2 As shown, the excitation source 7 and the storage cell are both located on the magnetic insulating layer 1. Their relative orientation is not strictly limited. However, it should be noted that the direction of the current flowing into the excitation source 7 is in-plane and parallel or antiparallel to the magnetic moment direction of the free layer 3. When the current flows in a certain direction, due to the spin-orbit coupling effect, spin accumulation is generated inside the excitation source 7, which in turn excites the magnetic insulating layer 1 to generate a magneton. The polarization direction of the magneton is determined by the current direction. After the magneton is generated, it propagates in-plane. Its propagation direction is from the excitation source 7 to the storage cell, that is, the region where the non-magnetic spacer layer 2 and the free layer 3 are located, or perpendicular to the magnetic moment direction of the free layer 3.

[0026] In this embodiment, the current flowing through the excitation source 7 is not limited to DC or alternating current. When DC current is used, a continuous magnetic particle flow can be stably generated. When pulsed current is used, a fast and low-power write operation can be achieved. When current is flowing through the excitation source 7, spin accumulation excites the magnetic insulating layer 1 to generate magnetic particles. The magnetic particles propagate to the interface between the magnetic insulating layer 1 and the non-magnetic spacer layer 2, and are converted into a spin flow through the spin pumping effect, thereby realizing the reversal of the magnetic moment of the free layer. By changing the direction of the current in the excitation source 7, the polarization direction of the magnetic particles can be changed, thereby determining the final magnetization reversal direction of the free layer 3 and realizing the switching between storage states 0 and 1.

[0027] To further improve the magnetic injection efficiency, an extremely thin oxide interface layer, such as MgO with a thickness of <1 nm, can be introduced between the excitation source 7 and the magnetic insulating layer 1 to enhance the interface spin transmittance. Meanwhile, the width and length of the excitation source 7 can be optimized according to the size of the storage cell, typically with a width of 50–500 nm and a length of 100 nm–2 μm, to obtain sufficient spin current density.

[0028] This embodiment achieves a Joule-free hot writing method based on magnetic particle propagation through magnetic insulating layer 1 and excitation source 7. At the same time, by selecting the material of excitation source 7 and controlling the current direction, high-efficiency, low-power, and highly controllable magnetic particle excitation and free layer flipping capability are obtained.

[0029] In this embodiment, the non-magnetic spacer layer 2 is disposed on one side of the magnetic insulating layer 1. The magnetic insulating layer 1 is used to generate and propagate magnetic particles in the in-plane direction in response to external excitation. A spin accumulation region is formed at the interface between the magnetic insulating layer 1 and the non-magnetic spacer layer 2 to generate a spin flow perpendicular to the interface.

[0030] In this embodiment, the material of the non-magnetic spacer layer 2 is a metal with a long spin diffusion length, including at least one of Cu, Ag or Au. In this embodiment, the material of the non-magnetic spacer layer 2 is preferably Cu, and the thickness is 2 nm to 10 nm, more preferably 5 nm.

[0031] It should be noted that the non-magnetic spacer layer 2 is made of a metal with a long spin diffusion length, which ensures that the spin current propagates from the magnetic insulating layer 1 to the free layer 3 with virtually no loss, thereby ensuring sufficient spin current density to be injected into the free layer 3 to achieve magnetic moment reversal.

[0032] Furthermore, during information reading operations, the non-magnetic spacer layer 2 can serve as a second electrode layer for the reading current. Therefore, its resistivity is required to be as low as possible to reduce voltage drop and power consumption on the reading path. In this embodiment, the materials such as Cu, Ag, and Au selected all have low resistivity, which meets the reading requirements.

[0033] The addition of the non-magnetic spacer layer 2 causes magnetic decoupling between the magnetic insulating layer 1 and the free layer 3. Specifically, if the magnetic insulating layer 1 and the free layer 3 are in direct contact, since both are magnetic materials, direct magnetic coupling will occur between them, including ferromagnetic coupling or antiferromagnetic coupling. This coupling effect causes the magnetic moments of the two magnetic materials to tend to be parallel or antiparallel. The natural coupling tendency will generate additional resistance in the subsequent process of flipping the magnetic moment of the free layer 3 through spin current. A higher spin current density is required to overcome this coupling effect, thereby increasing the writing power consumption.

[0034] In this embodiment, the addition of the non-magnetic spacer layer 2 prevents the magnetic insulating layer 1 and the free layer 3 from direct contact, eliminating the direct magnetic coupling effect between them. The magnetic moment of the free layer 3 is no longer pinned or biased by the magnetic moment of the magnetic insulating layer 1, and can be freely flipped under the action of a small spin current torque, thereby reducing the threshold current and power consumption of the write operation.

[0035] Meanwhile, the presence of the non-magnetic spacer layer 2 also introduces an indirect exchange interaction between the magnetic insulating layer 1 and the free layer 3. The strength and nature of the indirect exchange interaction can be controlled by adjusting the material type and thickness of the non-magnetic spacer layer 2, thereby optimizing the coercivity and thermal stability of the free layer 3 and improving the reliability of stored information.

[0036] To ensure the quality of the interface between the non-magnetic spacer layer 2 and the magnetic insulating layer 1 and to maximize spin pumping efficiency, the surface of the magnetic insulating layer 1 can be subjected to in-situ annealing or ion beam cleaning before depositing the non-magnetic spacer layer 2 to remove surface adsorbed impurities and obtain an atomically smooth interface. The non-magnetic spacer layer 2 can be deposited by methods such as magnetron sputtering, electron beam evaporation or molecular beam epitaxy. The deposition rate should be controlled in the range of 0.1 nm / s to 0.5 nm / s to obtain a dense, continuous film with a clear interface.

[0037] At the interface between the magnetic insulating layer 1 and the non-magnetic spacer layer 2, the magnetic wave is converted into a spin current through the spin pumping effect. This spin current is injected into the non-magnetic spacer layer 2 perpendicular to the interface, and then passes through the non-magnetic spacer layer 2 along the thickness direction to enter the free layer 3. The thickness of the non-magnetic spacer layer 2 should be thin enough, ≤10nm, to ensure that the spin current does not attenuate significantly during transmission. At the same time, it should be thick enough, ≥2nm, to effectively decouple the direct magnetic coupling between the magnetic insulating layer 1 and the free layer 3. In this embodiment, the thickness of the non-magnetic spacer layer 2 is 5nm.

[0038] The free layer 3 is disposed on the side of the non-magnetic spacer layer 2 away from the magnetic insulating layer 1. The free layer 3 is magnetic and is used to receive spin current and generate torque for reversing its magnetization direction. In this embodiment, the materials of the free layer 3 and the reference layer 5 are ferromagnetic metals, including at least one of Co, Fe, Ni and their alloys CoFeB, CoFe, or NiFe. The thickness of the free layer 3 is 0.5 nm to 10 nm. More preferably, it is 0.5 nm to 4 nm. A thinner free layer helps to reduce the critical spin current density required for flipping, thereby further reducing write power consumption.

[0039] It should be noted that the initial direction of the magnetic moment of the free layer 3 can be in-plane or perpendicular, depending on the design requirements of the memory. In this embodiment, the free layer 3 preferably has perpendicular magnetic anisotropy to achieve high-density integration and low flip-flop current. By adjusting the composition of the free layer 3 and the material and thickness of the barrier layer 4, good perpendicular magnetic anisotropy can be obtained.

[0040] To ensure the interface quality between the free layer 3, the non-magnetic spacer layer 2, and the barrier layer 4, the surface of the non-magnetic spacer layer 2 can be cleaned or annealed in situ before depositing the free layer 3. The free layer 3 can be deposited by magnetron sputtering, with the deposition rate controlled in the range of 0.05 nm / s to 0.2 nm / s, in order to obtain a uniform and continuous thin film.

[0041] In this embodiment, the barrier layer 4 is disposed on the side of the free layer 3 away from the non-magnetic spacer layer 2, which is used to allow tunneling current to pass through and prevent spin current from propagating to the reference layer 5. Specifically, barrier layer 4 has a dual function: during read operations, it allows tunneling current to pass through, forming a read path; during write operations, it prevents spin current from continuing to propagate to reference layer 5, concentrating spin current energy within free layer 3, thereby improving flipping efficiency.

[0042] In this embodiment, the barrier layer 4 is made of a non-magnetic insulating material, including at least one of MgO or Al2O3. The thickness of the barrier layer 4 is 0.8 nm to 2 nm, more preferably 1.1 nm to 1.4 nm. This thickness range ensures both a sufficient tunneling magnetoresistance ratio and effective blocking of spin current.

[0043] It should be noted that when the barrier layer 4 is made of MgO and has a crystal orientation, a high tunneling magnetoresistance ratio can be generated. At the same time, the MgO interface can also enhance the vertical magnetic anisotropy of the free layer 3. Therefore, in this embodiment, MgO is preferred as the barrier layer material, and after deposition, it is crystallized by in-situ annealing to obtain the texture.

[0044] In this embodiment, the barrier layer 4 can be deposited by radio frequency magnetron sputtering or molecular beam epitaxy. During the deposition process, the substrate temperature should be kept between room temperature and 300°C to control the crystallization quality of MgO. After deposition, rapid thermal annealing can be performed, such as at 300°C to 400°C for 0.5 to 1 hour, to promote MgO crystallization and improve the quality of the free layer / barrier layer interface.

[0045] In this embodiment, the reference layer 5 is disposed on the side of the barrier layer 4 away from the free layer 3. The reference layer 5 is magnetic and the magnetic moment is pinned to provide a fixed reference magnetic moment direction. It is parallel or antiparallel to the magnetic rectangle of the free layer 3, respectively corresponding to the storage state identifier 0 or 1.

[0046] In this embodiment, the material of the reference layer 5 is a ferromagnetic metal, including but not limited to at least one of Co, Fe, Ni and their alloys CoFeB, CoFe or NiFe. The thickness of the reference layer 5 is 2 nm to 10 nm. The reference layer 5 can be composed of the same or different ferromagnetic materials as the free layer 3. To ensure the stability of the magnetic moment of the reference layer 5, the reference layer 5 usually has a higher magnetic anisotropy than the free layer 3, for example, by using a [Co / Pt] or [Co / Pd] multilayer film structure, or by pinning with an antiferromagnetic layer.

[0047] More preferably, the reference layer 5 adopts a synthetic antiferromagnetic structure, which is formed by two ferromagnetic layers coupled through an antiferromagnetic coupling layer. The SAF structure can effectively pin the magnetic moment of the reference layer 5 and suppress its response to external magnetic fields, thereby improving the thermal stability and anti-interference capability of the memory.

[0048] In this embodiment, the pinning of the reference layer 5 can be achieved by depositing an antiferromagnetic pinning layer, such as IrMn, with a thickness of 5nm to 10nm on top of the reference layer 5, and then annealing it in a magnetic field, for example, at 300°C, with an external magnetic field of about 1T, for 1 hour. During the process, the magnetic moment direction of the reference layer 5 is set. After annealing, an exchange bias is generated between the antiferromagnetic layer and the reference layer 5, thereby fixing the magnetic moment of the reference layer 5.

[0049] A magnetic tunnel junction is formed by stacking a reference layer 5, a barrier layer 4, and a free layer 3 in sequence. After the deposition of the above layers is completed, the entire stacked structure usually needs to be annealed to optimize the crystal quality and interface characteristics of each layer. In this embodiment, the annealing temperature is preferably 300℃~400℃, the annealing time is 30 minutes~60 minutes, and an in-plane or vertical magnetic field is applied to set the magnetic moment direction of the reference layer 5. After annealing, a good interface is formed between the free layer 3 and the barrier layer 4.

[0050] By using free layer 3, barrier layer 4, and reference layer 5, efficient writing based on magnetic torque and high-sensitivity tunneling magnetoresistive reading are achieved. Barrier layer 4 effectively blocks spin current during writing, improving flipping efficiency, and provides a high tunneling magnetoresistive ratio during reading, ensuring the reliability and stability of read and write operations. Meanwhile, reference layer 5 provides a stable reference magnetic moment through a pinning structure, ensuring the non-volatility of the stored state.

[0051] This embodiment also includes a first electrode layer 6, which is disposed on the side of the reference layer 5 away from the barrier layer 4, and is used to pass a read current during a read operation. The read current is less than the flip current of the free layer 3.

[0052] It should be noted that the first electrode layer 6 serves as the input terminal for the read current. During the read operation, it, together with the reference layer 5, the barrier layer 4, the free layer 3, and the non-magnetic spacer layer 2, forms a read circuit. The read current is introduced through the first electrode layer 6, passes through the reference layer 5, the barrier layer 4, and the free layer 3 in sequence, and finally flows out from the non-magnetic spacer layer 2. During this process, the tunneling magnetoresistance effect is utilized to read the stored information based on the low-resistance state or high-resistance state corresponding to the parallel or anti-parallel state of the magnetic moments of the reference layer 5 and the free layer 3.

[0053] The material of the first electrode layer 6 can be a metal with good conductivity, such as Ta, Pt, Au, Cu, Ru, TiN, etc. It can also adopt a multilayer structure, such as Ta / Cu / Ta, to balance adhesion and low resistivity. In this embodiment, the first electrode layer 6 preferably adopts a composite layer structure of Ta=5nm, Cu=50nm, and Ta=5nm, where Ta serves as an adhesion layer and a diffusion barrier layer, and Cu serves as the main conductive layer to reduce resistance. The total thickness of the first electrode layer 6 is usually 20nm to 100nm, and in this embodiment, it is preferably 60nm.

[0054] It should be noted that when the read current is injected into the reference layer 5 through the first electrode layer 6, the current is also polarized by the reference layer 5, generating a spin-polarized current. This spin-polarized current, after passing through the barrier layer 4 and entering the free layer 3, may generate an additional magneton torque on the magnetic moment of the free layer 3. If the read current is too large, it may accidentally reverse the magnetization direction of the free layer 3, leading to erroneous rewriting of the stored information. Therefore, the magnitude of the read current must be less than the reversal current threshold of the free layer 3, which is approximately 10-1. 6 A / cm 2 ~10 7 A / cm 2 In this embodiment, the read current density is controlled at 10. 4 A / cm 2 ~10 5 A / cm 2 Within this range, the read current is approximately 1 / 100 to 1 / 10 of the flip current, ensuring the non-destructive nature of the read operation.

[0055] To ensure uniform distribution of read current, the first electrode layer 6 should cover the entire upper surface of the reference layer 5. Its planar dimensions can be the same as or slightly larger than those of the reference layer 5. The first electrode layer 6 can be deposited by magnetron sputtering or electron beam evaporation and patterned using photolithography and dry etching processes.

[0056] In addition, the first electrode layer 6 is not subject to any voltage or current during the write operation and can be left floating or grounded to avoid interfering with the write process.

[0057] Secondly, the present invention also provides a read / write method for a magnetic memory based on magnetic field writing, which is implemented using a magnetic memory based on magnetic field writing and includes the following steps: S1, during the write operation, a magneton is generated in the magnetic insulating layer 1 by passing an in-plane current through the excitation source 7. It should be noted that the direction of the current flowing into the excitation source 7 is in-plane and parallel or antiparallel to the magnetic moment direction of the free layer 3. When the current flows in a certain direction, due to the spin-orbit coupling effect, spin accumulation is generated inside the excitation source 7, which in turn excites the magnetic insulating layer 1 to generate a magnet with a specific polarization direction. By changing the current direction, the polarization direction of the magnet can be changed, thereby controlling the subsequent magnetic moment reversal direction of the free layer 3. The current can be a direct current or a pulsed current. In this embodiment, a pulsed current with a pulse width of 1ns to 100ns is preferably used to achieve fast and low-power writing.

[0058] S2, the magnetic particle propagates in the in-plane direction within the magnetic insulating layer 1 and reaches the interface between the magnetic insulating layer 1 and the non-magnetic spacer layer 2. It should be noted that the magnetic particle propagates in the in-plane direction within the magnetic insulating layer 1 and reaches the interface between the magnetic insulating layer 1 and the non-magnetic spacer layer 2. Since the magnetic insulating layer 1 is an insulating material, no charge flow accompanies the magnetic particle during propagation, thus no Joule heat loss occurs. The low damping coefficient of the magnetic insulating layer 1 allows the magnetic particle to propagate over long distances without significant attenuation.

[0059] S3 generates spin accumulation at the interface through the spin pumping effect, forming a spin flow perpendicular to the interface; It should be noted that at the interface between the magnetic insulating layer 1 and the non-magnetic spacer layer 2, spin accumulation is generated through the spin pumping effect, forming a spin flow perpendicular to the interface. Specifically, the spin angular momentum carried by the magnetic particles is transferred to the conduction electrons in the non-magnetic spacer layer 2 at the interface, causing these electrons to spin polarize and forming a spin flow flowing along the thickness direction. The magnitude of the spin flow is proportional to the magnetic particle flow density and the interface spin mixing conductivity. By optimizing the interface quality, the spin pumping efficiency can be maximized.

[0060] S4, the spin flow is injected into the free layer 3 through the non-magnetic spacer layer 2, and the barrier layer 4 prevents the spin flow from continuing to propagate to the reference layer 5, thus confining the spin flow within the free layer 3. It should be noted that the spin flow is injected into the free layer 3 through the non-magnetic spacer layer 2. Since the non-magnetic spacer layer 2 has a long spin diffusion length, the spin flow has very low loss when passing through the layer. At the same time, the barrier layer 4 prevents the spin flow from continuing to propagate to the reference layer 5, thus confining the spin flow within the free layer 3. This ensures that all the energy of the spin flow is used for the magnetic moment reversal of the free layer 3, thereby improving the reversal efficiency.

[0061] S5, the spin flow generates a magneton torque in the free layer 3, reversing the magnetization direction of the free layer 3; It should be noted that the spin current generates a magneton torque in the free layer 3, which flips the magnetization direction of the free layer 3. The magnitude of the magneton torque is proportional to the injected spin current density. When the spin current density exceeds the critical flip current density of the free layer 3, the magnetization direction of the free layer 3 is flipped. The thickness of the free layer 3 is preferably 0.5nm to 4nm. Within this thickness range, the critical flip current density is relatively low, which is beneficial to reducing write power consumption.

[0062] S6, depending on whether the magnetic moments of the free layer 3 and the reference layer 5 are parallel or antiparallel, the storage state identifier 0 or 1 is respectively. It should be noted that the parallel or antiparallel states of the magnetic moments of the free layer 3 and the reference layer 5 correspond to storage state identifiers 0 and 1, respectively. Specifically, when the magnetic moment direction of the free layer 3 is the same as that of the reference layer 5, it corresponds to storage state 0; when the two directions are opposite, it corresponds to the other storage state. In this embodiment, the correspondence can be flexibly defined according to the actual application and is not limited to a fixed mapping.

[0063] S7. During the read operation, a read current is passed between the first electrode layer 6 and the non-magnetic spacer layer 2. The read current passes through the reference layer 5, the barrier layer 4, the free layer 3 and the non-magnetic spacer layer 2 in sequence. Based on the low resistance state or high resistance state corresponding to the parallel or antiparallel magnetic moments of the reference layer 5 and the free layer 3, the corresponding storage state identifier 0 or 1 is read by detecting the low resistance state or high resistance state.

[0064] During the read operation, a read current is passed between the first electrode layer 6 and the non-magnetic spacer layer 2. The read current passes through the reference layer 5, the barrier layer 4, the free layer 3 and the non-magnetic spacer layer 2 in sequence. Based on the low resistance state or high resistance state corresponding to the parallel or antiparallel magnetic moments of the reference layer 5 and the free layer 3, the corresponding storage state identifier 0 or 1 is read by detecting the low resistance state or the high resistance state.

[0065] Specifically, due to the tunneling magnetoresistance effect, when the magnetic moments of the reference layer 5 and the free layer 3 are parallel, the probability of electrons tunneling through the barrier layer 4 is high, and the tunnel junction exhibits a low-resistance state; when the two are antiparallel, the probability of electrons tunneling is low, and the tunnel junction exhibits a high-resistance state. The current resistance state can be determined by reading the magnitude of the current, thereby determining the stored information.

[0066] It is important to note that the read current must be less than the flip current of free layer 3. This is because when the read current passes through reference layer 5, it is polarized by reference layer 5, generating a spin-polarized current. This spin-polarized current, after passing through barrier layer 4 and entering free layer 3, may generate an additional magneton torque on the magnetic moment of free layer 3. If the read current is too large, it may accidentally flip the magnetization direction of free layer 3, leading to erroneous rewriting of the stored information. Therefore, in this embodiment, the read current density is controlled at 10. 4 A / cm 2 ~10 5 A / cm 2 Within this range, the critical flip current density is much lower than that of free layer 3, thus ensuring the non-destructive nature of the read operation.

[0067] In the above read / write method, the write operation is entirely based on the propagation of magnetic particles in the insulator and the injection of spin current. There is no charge flow in the write path, which fundamentally eliminates Joule heat loss and achieves ultra-low power writing. At the same time, the barrier layer blocks the spin flow to the reference layer during writing, improving the flip-flop efficiency. The non-magnetic spacer layer decouples the magnetic insulating layer from the free layer, reducing the flip-flop resistance. The read operation uses an independent read path and a read current below the flip-flop threshold, achieving non-destructive reading. Furthermore, the read / write separation design allows write and read operations to be optimized independently, improving the overall performance of the memory.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnetic memory based on magnetic writing, characterized in that, It includes a magnetic insulating layer (1), a non-magnetic spacer layer (2), a free layer (3), a barrier layer (4), and a reference layer (5); A non-magnetic spacer layer (2) is disposed on one side of a magnetic insulating layer (1). The magnetic insulating layer (1) is used to generate and propagate magnetic particles in the in-plane direction in response to external excitation. A spin accumulation region is formed at the interface between the magnetic insulating layer (1) and the non-magnetic spacer layer (2) to generate a spin flow perpendicular to the interface. A free layer (3) is disposed on the side of the non-magnetic spacer layer (2) away from the magnetic insulating layer (1). The free layer (3) is magnetic and is used to receive spin current and generate torque for reversing its magnetization direction. The barrier layer (4) is located on the side of the free layer (3) away from the non-magnetic spacer layer (2) to allow tunneling current to pass through and to prevent spin current from propagating to the reference layer (5); The reference layer (5) is disposed on the side of the barrier layer (4) away from the free layer (3). The reference layer (5) is magnetic and the magnetic moment is pinned to provide a fixed reference magnetic moment direction and is parallel or antiparallel to the magnetic rectangle of the free layer (3), respectively corresponding to the storage state identifier 0 or 1.

2. The magnetic memory based on magnetic particle writing as described in claim 1, characterized in that, It also includes a first electrode layer (6), which is disposed on the side of the reference layer (5) away from the barrier layer (4) for passing a read current during a read operation. The read current is less than the flip current of the free layer (3).

3. The magnetic memory based on magnetic particle writing as described in claim 1, characterized in that, It also includes an excitation source (7), which is disposed on the magnetic insulating layer (1) and is used to excite the magnetic insulating layer (1) to generate magnets when an in-plane current is passed through it. The direction of the current passed through the excitation source (7) is in-plane and parallel or antiparallel to the magnetic moment direction of the free layer (3).

4. The magnetic memory based on magnetic particle writing as described in claim 1, characterized in that, The material of the magnetic insulating layer (1) is a magnetic insulator, including at least one of YIG, TmIG, BFO, α-Fe2O3, gadolinium gallium garnet, gadoferroic garnet or Fe5GeTe2.

5. The magnetic memory based on magnetic particle writing as described in claim 1, characterized in that, The thickness of the magnetic insulating layer (1) is 0.5 nm to 50 nm.

6. The magnetic memory based on magnetic particle writing as described in claim 1, characterized in that, The materials of the free layer (3) and the reference layer (5) are ferromagnetic metals, including at least one of Co, Fe, Ni and their alloys CoFeB, CoFe or NiFe, and the thickness of the free layer (3) is 0.5 nm to 10 nm.

7. The magnetic memory based on magnetic particle writing as described in claim 1, characterized in that, The barrier layer (4) is made of a non-magnetic insulating material, including at least one of MgO or Al2O3, and the thickness of the barrier layer (4) is 0.8 nm to 2 nm.

8. The magnetic memory based on magnetic particle writing as described in claim 1, characterized in that, The material of the non-magnetic spacer layer (2) is a metal with a long spin diffusion length, including at least one of Cu, Ag or Au.

9. The magnetic memory based on magnetic particle writing as described in claim 3, characterized in that, The material of the excitation source (7) is a heavy metal or topological insulator with strong spin-orbit coupling, including Pt, Ta, Pd, Ir, W, Pb, Hf or their alloys, and at least one of Bi2Se3 or Bi2Te3.

10. A read / write method for a magnetic memory based on magnetic field writing, implemented using the magnetic memory based on magnetic field writing as described in any one of claims 1-9, characterized in that, Includes the following steps: S1, during the write operation, a magneton is generated in the magnetic insulating layer (1) by passing an in-plane current through the excitation source (7); S2, the magnetic particle propagates in the in-plane direction within the magnetic insulating layer (1) and reaches the interface between the magnetic insulating layer (1) and the non-magnetic spacer layer (2); S3 generates spin accumulation at the interface through the spin pumping effect, forming a spin flow perpendicular to the interface; S4, the spin flow is injected into the free layer (3) through the non-magnetic spacer layer (2), and the barrier layer (4) prevents the spin flow from continuing to propagate to the reference layer (5), thus confining the spin flow within the free layer (3); S5, the spin flow generates a magneton torque in the free layer (3), which reverses the magnetization direction of the free layer (3); S6, depending on whether the magnetic moments of the free layer (3) and the reference layer (5) are parallel or antiparallel, the storage state identifiers 0 and 1 are respectively. S7. When performing a read operation, a read current is passed between the first electrode layer (6) and the non-magnetic spacer layer (2). The read current passes through the reference layer (5), the barrier layer (4), the free layer (3), and the non-magnetic spacer layer (2) in sequence. Based on the low resistance state or high resistance state corresponding to the parallel or antiparallel magnetic moments of the reference layer (5) and the free layer (3), the corresponding storage state identifier 0 or 1 is read by detecting the low resistance state or high resistance state.

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