Storage cells and their fabrication methods, memory and information storage methods

Abstract

This disclosure provides a storage cell and its fabrication method, a memory, and an information storage method. The storage cell includes a piezoelectric substrate layer with a first electrode and a second electrode at its two ends, respectively. A current-free drive for skyrmions is achieved by applying a voltage to the first and second electrodes. A magnetic layer, located on the surface of the piezoelectric substrate layer, forms a heterojunction with the piezoelectric substrate layer and is used to generate, stabilize, and serve as the basic carrier for skyrmion movement. The magnetic layer includes a convex body that divides the magnetic layer into a bit region and a storage region. The bit region contains a magnetic tunnel junction for performing skyrmion generation and detection functions.

Description

Technical Field

[0001] This disclosure relates to the field of spintronics technology, specifically to a storage unit and its fabrication method, a memory, and an information storage method. Background Technology

[0002] Skyrmions possess numerous superior characteristics, including unique topology protection, high stability, extremely compact size, and a drive current threshold that is 5 to 6 orders of magnitude lower than that of magnetic domain walls. These characteristics make skyrmion-based race track memories a promising candidate to surpass traditional magnetic domain wall race track memories and become the next generation of high-density non-volatile memories.

[0003] While skyrmion-based track memory offers advantages such as ultra-high storage density, low power consumption, and non-volatility, it still faces numerous challenges. For example, track memory relies on the coordinated movement of all skyrmions on the nanoribbon; if a single skyrmion is accidentally pinned, the entire nanoribbon's data can become corrupted or even crash. Furthermore, the current threshold for driving skyrmions deviates significantly from theoretical predictions because when defects are smaller than the skyrmion's size, the skyrmion cannot effectively avoid them, implying extremely stringent manufacturing requirements. Additionally, skyrmions are inevitably affected by the skyrmion Hall effect (SKHE) during their movement; under the influence of transverse Magnus forces, skyrmions gradually shift towards the track edge, where high currents can cause them to annihilate. To avoid this, track memory must employ a trade-off between current density (write rate) and track width (storage density). Furthermore, skyrmions are prone to non-ideal displacement under the interference of external environmental factors such as noise, thermal fluctuations, and vibrations, which poses a significant challenge to the non-volatility of memory. Summary of the Invention

[0004] In view of this, the present disclosure provides a storage unit and its preparation method, a memory, and an information storage method, in order to at least partially solve the above-mentioned technical problems.

[0005] According to one aspect of this disclosure, a storage cell is provided, comprising: a piezoelectric substrate layer having a first electrode and a second electrode respectively at its two ends, wherein a current-free drive for skyrmions is achieved by applying a voltage to the first electrode and the second electrode; a magnetic layer located on the surface of the piezoelectric substrate layer, forming a heterojunction with the piezoelectric substrate layer, used for generating, stabilizing and serving as the basic carrier for skyrmion movement; wherein the magnetic layer includes a convex body that divides the magnetic layer into a bit region and a storage region, and a magnetic tunnel junction is provided in the bit region for performing skyrmion generation and detection functions.

[0006] According to embodiments of this disclosure, the piezoelectric substrate layer generates strain under the action of an electric field, and the strain is transmitted to the magnetic layer through the heterojunction to drive skyrmions to move on the magnetic layer.

[0007] According to embodiments of this disclosure, current is injected in a direction perpendicular to the surface of the magnetic tunnel junction to induce the formation of stable skyrmions in the bit region.

[0008] According to embodiments of this disclosure, the magnetic tunnel junction detects the presence of skyrmions in the bit region based on the tunneling magnetoresistance effect. If a skyrmion is present, it is recorded as a "0" bit state; conversely, if the skyrmion is located in the storage region, it is recorded as a "1" bit state. When the skyrmion is located in the bit region, a first voltage is applied to the first electrode and the second electrode to drive the skyrmion to move from the bit region to the storage region, thereby achieving a switch from a "0" bit state to a "1" bit state. When a second voltage is applied to the first electrode and the second electrode, the skyrmion is driven to move from the storage region to the bit region, thereby achieving a switch from a "1" bit state to a "0" bit state, wherein the direction of the second voltage is opposite to the direction of the first voltage.

[0009] According to embodiments of this disclosure, skyrmions move along the direction of increasing strain.

[0010] According to embodiments of this disclosure, the piezoelectric substrate layer is made of one or more of lead zirconate titanate, lead magnesium niobate titanate, La-BiFeO3, Sm-BiFeO3, and BaTiO3-BiMgTiO3.

[0011] According to embodiments of this disclosure, the height of the convex body is higher than the height of the bit area and the storage area, so that when the skyrmions are confined to one region of the magnetic layer, they will not move to another region due to disturbances from the external environment.

[0012] According to embodiments of this disclosure, the magnetic layer is made of one or more of Co, CoFeB, CoFe, and FeNi.

[0013] According to embodiments of this disclosure, the memory cell further includes a heavy metal layer located between the piezoelectric substrate layer and the magnetic layer for providing antisymmetric exchange coupling interaction.

[0014] According to embodiments of this disclosure, the material of the heavy metal layer includes one or more of W, Ta, Pt, Pd, Ph, Ir, Pb, and Au.

[0015] According to another aspect of this disclosure, an information storage method is provided, applied to the storage cell described above, comprising: applying a first current to a magnetic tunnel junction to form stable skyrmions in the bit region of a magnetic layer; and applying a first voltage to a first electrode and a second electrode to generate a first strain in a piezoelectric substrate layer, the first strain being transmitted to the magnetic layer through a heterojunction to drive the skyrmions from the bit region of the magnetic layer to the storage region of the magnetic layer, thereby realizing the writing of information to be stored.

[0016] According to an embodiment of this disclosure, the method further includes: applying a second voltage to the first electrode and the second electrode to generate a second strain in the piezoelectric substrate layer, the second strain being transmitted to the magnetic layer through the heterojunction to drive skyrmions from the storage region of the magnetic layer to the bit region of the magnetic layer, thereby erasing the information to be stored; the direction of the second voltage is opposite to the direction of the first voltage.

[0017] According to embodiments of this disclosure, the method further includes: applying a second current to the magnetic tunnel junction, reading the resistance state information of the magnetic tunnel junction, and realizing the reading of the information to be stored.

[0018] According to embodiments of this disclosure, the speed at which skyrmions move between the bit region and the storage region of the magnetic layer is determined based on the voltage values ​​applied to the first and second electrodes.

[0019] According to embodiments of this disclosure, when a skyrmion is located in the storage area of ​​the magnetic layer, it corresponds to a "1" bit state; when a skyrmion is located in the bit area of ​​the magnetic layer, it corresponds to a "0" bit state.

[0020] According to another aspect of this disclosure, a method for fabricating a memory cell is provided, comprising: fabricating a magnetic layer on a piezoelectric substrate; the magnetic layer including a convex body for dividing the magnetic layer into a bit region and a memory region; fabricating a magnetic tunnel junction within the bit region of the magnetic layer; and fabricating a first electrode and a second electrode at both ends of the piezoelectric substrate.

[0021] According to embodiments of this disclosure, the method further includes: preparing a heavy metal layer between a piezoelectric substrate layer and a magnetic layer.

[0022] According to another aspect of this disclosure, a memory is provided, which includes a memory cell as described in any one of the above embodiments, or a memory cell prepared by the preparation method described in any one of the above embodiments. Attached Figure Description

[0023] To further illustrate the technical content of this disclosure, the following will provide a detailed description in conjunction with examples and accompanying drawings, wherein:

[0024] Figure 1 This is a front view of a storage unit according to an embodiment of the present disclosure;

[0025] Figure 2 This is a top view of a storage unit according to an embodiment of the present disclosure;

[0026] Figure 3 This is a data type representation diagram according to an embodiment of the present disclosure;

[0027] Figure 4 This is a schematic diagram of the dynamic trajectory of skyrmions on a magnetic layer according to an embodiment of the present disclosure;

[0028] Figure 5 It is a strain curve of the piezoelectric substrate layer on the magnetic layer according to an embodiment of the present disclosure;

[0029] Figure 6 This is a simulation result of strain-driven mumax3 of a skyrmion according to an embodiment of this disclosure;

[0030] Figure 7 This is a flowchart of a method for preparing a storage cell according to an embodiment of the present disclosure;

[0031] Figure 8 This is a flowchart of an information storage method according to an embodiment of the present disclosure.

[0032] Explanation of reference numerals in the attached figures:

[0033] 110: Piezoelectric substrate; 120: Magnetic layer; 121: Convex body; 122: Bit region; 123: Storage region; 130: Magnetic tunnel junction; 140: First electrode; 150: Second electrode; 10: Skyrmion; 301-302, 601-603: Process. Detailed Implementation

[0034] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the embodiments and the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0035] It should be noted that similar or identical parts are referred to by the same reference numerals in the accompanying drawings or description. Implementations not shown or described in the drawings are forms known to those skilled in the art. Furthermore, while this document provides examples of parameters containing specific values, it should be understood that the parameters need not be exactly equal to the corresponding values, but can approximate the corresponding values ​​within acceptable error tolerances or design constraints. Additionally, directional terms mentioned in the following embodiments, such as "up," "down," "front," "back," "left," "right," "inner," and "outer," are merely for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the scope of this disclosure.

[0036] Furthermore, in the embodiments of this disclosure, if there are descriptions involving "first," "second," etc., such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features.

[0037] Skyrmions possess numerous superior characteristics, including unique topology protection, high stability, extremely compact size, and a drive current threshold that is 5–6 orders of magnitude lower than that of magnetic domain walls. These characteristics make skyrmion-based race track memories a promising candidate to surpass traditional magnetic domain wall race track memories and become the next generation of high-density non-volatile memories.

[0038] In realizing the concept disclosed herein, the inventors discovered that skyrmion-based track memory still faces numerous problems. First, track memory storage relies on the coordinated movement of all skyrmions on the nanoribbon; if a skyrmion is accidentally pinned, it can lead to data corruption or even data loss across the entire nanoribbon. Second, the current threshold for driving skyrmions differs significantly from theoretical predictions. This is because when defects are smaller than the skyrmion's size, the skyrmion cannot effectively avoid them, meaning that track memory requires extremely stringent manufacturing processes. Third, skyrmions are inevitably affected by the skyrmion Hall effect during movement; under the influence of transverse Magnus forces, skyrmions gradually shift towards the track edge, leading to annihilation under high current. To avoid this phenomenon, track memory must employ a trade-off between current density (write rate) and "track" width (storage density). Finally, skyrmions are prone to non-ideal displacement under external environmental interference such as noise, thermal fluctuations, and vibrations, posing a significant challenge to the memory's non-volatility.

[0039] In view of this, this disclosure proposes a storage unit and its preparation method, a memory, and an information storage method, in order to at least partially solve the above-mentioned technical problems.

[0040] Figure 1 This is a front view of a storage unit according to an embodiment of the present disclosure. Figure 2 This is a top view of a storage unit according to an embodiment of the present disclosure.

[0041] Please also refer to Figure 1 and Figure 2 The storage cell includes a piezoelectric substrate layer 110 and a magnetic layer 120. A first electrode 140 and a second electrode 150 are respectively provided at both ends of the piezoelectric substrate layer 110. The magnetic layer 120 is located on the surface of the piezoelectric substrate layer 110, forming a heterojunction with the piezoelectric substrate layer 110, and is used for generating, stabilizing, and serving as the basic carrier for skyrmion motion. The magnetic layer 120 includes a convex body 121, which divides the magnetic layer 120 into a bit region 122 and a storage region 123. A magnetic tunnel junction 130 is provided within the bit region 122.

[0042] In this embodiment, the magnetic tunnel junction 130 can be used to induce and detect skyrmions. When current is injected into the magnetic tunnel junction 130 in a direction perpendicular to its surface, it can be polarized into a spin-polarized current. Under the induction of the spin-polarized current, the magnetic layer 120 can form stable Bloch-type skyrmions in the bit region 122. Moreover, once stable skyrmions are formed in the bit region 122, there is no need to continue generating skyrmions. Compared to track memories that require continuous skyrmion generation to write information, the solution of this disclosure has better stability and high repeatability, and reduces the power consumption of the device.

[0043] The magnetic tunnel junction 130 can detect the presence of skyrmions in a corresponding region based on the tunneling magnetoresistive effect (TMR). For example, during the induced generation of skyrmions, the magnetic tunnel junction 130 can detect the presence of skyrmions in bit region 122 based on the tunneling magnetoresistive effect to determine whether stable skyrmions have been formed in bit region 122, thereby improving the reliability of the device.

[0044] In this embodiment, the position of a skyrmion on the magnetic layer 120 can represent different bit states. For example, if a skyrmion is located in bit region 122, it can represent a "0" bit state; if a skyrmion is located in storage region 123, it represents a "1" bit state. Therefore, by driving the skyrmions to "shuttle back and forth" between different regions of the magnetic layer 120, information storage can be achieved. It is understood that the correspondence between the position of a skyrmion on the magnetic layer 120 and different bit states is not limited to the above example; the specific correspondence between the skyrmion's position and the bit data can be set according to the actual application.

[0045] Figure 3This is a data type representation diagram according to an embodiment of the present disclosure. Reference will be made below. Figure 3 An example is given of the bit state corresponding to the location of the skymint. Figure 3 The diagram schematically illustrates bit state 301 when the skymin is located in bit area 122 and bit state 302 when the skymin is located in storage area 123.

[0046] like Figure 3 As shown, the convex body 121 divides the magnetic layer 120 into a bit region 122 and a storage region 123. If the skyrmion 10 is located in the bit region 122, the bit state can be represented as "0". If the skyrmion 10 is located in the storage region 123, the bit state can be represented as "1". Of course, this disclosure is not limited to this. In some embodiments, the bit state corresponding to the skyrmion 10 being located in the bit region 122 can be set to "1", and the bit state corresponding to the skyrmion 10 being located in the storage region 123 can be set to "0". Based on the above mechanism, information can be stored in a simple way by driving the skyrmion 10 to "shuttle back and forth" between different regions of the magnetic layer 120.

[0047] Since the location of a skymon can correspond to different bit states, the location of the skymon detected by the magnetic tunnel junction 130 can be used to read bit data. For example, if the skymon is located in bit region 122, it represents a "0" bit state; if the skymon is located in memory region 123, it represents a "1" bit state. Under this correspondence, when the magnetic tunnel junction 130 detects that the skymon 10 is located in bit region 122, it reads the bit data "0"; otherwise, it reads the bit data "1".

[0048] Return to reference Figure 1 and Figure 2 In this embodiment, the piezoelectric substrate 110 functions as a driving layer. Applying a voltage to the first electrode 140 and the second electrode 150 at both ends of the piezoelectric substrate 110 generates a potential difference along the entire longitudinal direction. Under the influence of the electric field, the piezoelectric substrate 110 exhibits the inverse piezoelectric effect, resulting in strain. This strain can be further transmitted to the magnetic layer 120 via the heterojunction to drive skyrmions to move on the magnetic layer 120. It is understood that the strain generated at different locations will vary, and along the direction of increasing potential, the strain gradually increases, causing the skyrmions to move along the direction of increasing strain. This achieves pure electric field driving of the skyrmions, thereby further reducing the power consumption and size of the device.

[0049] In this embodiment, the height of the convex body 121 can be slightly higher than the height of the bit region 122 and the storage region 123, thereby forming a certain potential barrier height at the convex body 121, which can functionally serve as a potential barrier region. Because the convex body 121 has a certain energy barrier, when a skyrmion is confined to a certain region of the magnetic layer 120, the skyrmion will not move to another region due to disturbances from the external environment (such as noise, thermal fluctuations, and vibrations). For example, when a skyrmion is located in the bit region 122, due to the existence of the intermediate potential barrier, the skyrmion will not move to the storage region 123 due to disturbances from the external environment. This avoids the skyrmion moving to another region due to the influence of the external environment, leading to information storage errors, thereby improving the stability and non-volatility of the storage.

[0050] Furthermore, the strength of the energy barrier of the convex body 121 is fixed, so the speed at which skyrmions pass through the barrier region can be controlled by changing the voltage applied to the first electrode 140 and the second electrode 150. It can be understood that when the voltage is low, the strain generated in the piezoelectric substrate 110 is small, resulting in a low skyrmion speed that may prevent them from passing through the barrier region, confining them within the bit region 122. As the voltage increases, the strain increases, and the skyrmion speed gradually increases. When the voltage across the device reaches a certain threshold, a sufficiently large strain is generated to drive the skyrmions across the barrier region to reach the storage region 123, thereby enabling the writing of bit information.

[0051] Figure 4 This is a schematic diagram of the dynamic trajectory of skyrmions on a magnetic layer according to an embodiment of the present disclosure.

[0052] Please refer to this as well. Figure 1 and Figure 4 When the skyrmion 10 is located in bit region 122, i.e., in the "0" bit state, a positive voltage is applied to the first electrode 140 and the second electrode 150 to induce a first strain in the piezoelectric substrate layer 110. This first strain is transmitted to the magnetic layer 120 through the heterojunction. Driven by the first strain, the skyrmion 10 gradually moves from bit region 122 to storage region 123 along the direction of increasing strain (parallel to the electric field), thereby achieving the switching from the "0" bit state to the "1" bit state.

[0053] During the above process, due to the Hall effect, skyrmion 10 also tends to deflect in the vertical direction. Therefore, the trajectory of skyrmion 10 is actually a curve that gradually deflects towards the edge of magnetic layer 120 (e.g., Figure 4(As shown). If the movement path of the skyrmion 10 is long, such as the movement of the skyrmion on the track memory, it will be detrimental to the reliability of data storage. However, in this embodiment of the disclosure, since the skyrmion 10 stores information by "shuttling back and forth" between the bit area 122 and the storage area 123, the skyrmion 10 only needs a short movement path to achieve information switching. Based on this, the Hall effect on the skyrmion 10 is not significant.

[0054] A reverse voltage (the direction of the reverse voltage is opposite to the direction of the forward voltage) is applied to the first electrode 140 and the second electrode 150 to induce a second strain in the piezoelectric substrate layer 110. This second strain is transmitted to the magnetic layer 120 through the heterojunction. Driven by the second strain, the skyrmion 10 returns from the storage region 123 to the bit region 122, thereby achieving a switch from a "1" bit state to a "0" bit state. During this process, the Magnus force is always perpendicular to the direction of motion. When the skyrmion 10 moves in the opposite direction (i.e., from the storage region 123 back to the bit region 122), the direction of the Magnus force also reverses, thus correcting the lateral displacement deflected by the Hall effect to some extent. Compared to racetrack memory, the scheme disclosed in this invention significantly improves the stability and reliability of the device.

[0055] It should be noted that the forward voltage described in this disclosure can refer to the potential of the first electrode 140 being lower than the potential of the second electrode 150. Correspondingly, the reverse voltage can refer to the potential of the first electrode 140 being higher than the potential of the second electrode 150. Of course, this disclosure is not limited to this.

[0056] Figure 5 This is a strain curve of the piezoelectric substrate layer on the magnetic layer according to an embodiment of the present disclosure. Figure 6 This is a simulation result of strain-driven mumax3 modeling of skyrmions according to an embodiment of this disclosure. The following references... Figure 5 and Figure 6 The process of skyrmions being driven by strain is explained.

[0057] exist Figure 5 In the diagram, the horizontal axis represents the distance in the x-direction, with units of nm. The vertical axis represents the component of the strain tensor in the x-direction, with units of 1. The x-direction can refer to the direction indicated by the skyrmion's trajectory.

[0058] In this embodiment of the disclosure, the first electrode 140 and the second electrode 150 ( Figure 1 When a positive voltage, for example, 2V, is applied between (as shown), the measured values ​​are as follows: Figure 5 The curve shown. The slope of the curve represents the strain gradient. For example... Figure 5As shown, in the x-direction within the range of 40–110 nm, along the direction of increasing potential, the strain transferred from the piezoelectric substrate 110 to the magnetic layer 120 through the heterojunction gradually increases, while the strain gradient remains essentially constant, with a magnitude of 1.6 × 10⁻⁶. -3 % / nm.

[0059] Figure 6 The simulation results of a skyrmion driven by strain in Mumax3 are shown. The magnitude of the strain gradient driving the skyrmion's motion can be represented by... Figure 5 The results are shown.

[0060] exist Figure 6 In the diagram, the length direction of the 192nm dimension can be the x-direction described above. Figures 601 to 603 show the positions of the skyrmion on the magnetic layer at different time points. During the processes shown in figures 601 to 603, the skyrmion can move along the direction of increasing strain, thus achieving low-power driving of the skyrmion with a purely electric field and no current.

[0061] In this disclosed technical solution, a piezoelectric substrate / magnetic layer heterojunction structure is utilized. An electric field is applied to the piezoelectric substrate, and the strain generated by the inverse piezoelectric effect drives the skyrmion, thereby achieving low-power driving of the skyrmion with a pure electric field and no current, reducing the power consumption of the device. Furthermore, the convex design avoids information storage errors caused by external environmental influences on the skyrmion, thus improving storage stability and non-volatility. In addition, the speed of the skyrmion can be controlled by changing the voltage applied to the piezoelectric substrate, thereby achieving high access speeds.

[0062] In some embodiments, the memory cell described above may further include a heavy metal layer located between the piezoelectric substrate layer and the magnetic layer. The heavy metal layer can provide an antisymmetric exchange coupling interaction (Dzyaloshinskii-Moriya Interaction, DMI) to generate stable Néel skyrmions within the bit region 122 of the magnetic layer 120.

[0063] In this embodiment, the piezoelectric substrate layer may be made of one or more of the following materials, including but not limited to lead zirconate titanate, lead magnesium niobate titanate, La-BiFeO3, Sm-BiFeO3, and BaTiO3-BiMgTiO3. The magnetic layer may be made of one or more of the following materials, including but not limited to Co, CoFeB, CoFe, and FeNi. The heavy metal layer may be made of one or more of the following materials, including but not limited to W, Ta, Pt, Pd, Ph, Ir, Pb, and Au.

[0064] According to embodiments of this disclosure, the size and quantity of the piezoelectric substrate, magnetic layer, and heavy metal layer can be designed according to actual application scenarios and are not limited herein.

[0065] According to embodiments of this disclosure, the first electrode and the second electrode may be formed of a material with good electrical conductivity, examples of which include, but are not limited to, Cu, Ag, and Ta. The dimensions of the first electrode and the second electrode are not particularly limited, as long as they are capable of providing an electric field to the piezoelectric substrate.

[0066] Based on the structure of the above-described memory cell, this disclosure also provides a method for fabricating the memory cell. The following will be combined with... Figure 7 The method is described in detail.

[0067] Figure 7 This is a flowchart of a method for preparing a storage cell according to an embodiment of the present disclosure.

[0068] like Figure 7 As shown, the method for preparing the memory cell includes steps S710 to S730.

[0069] In step S710, a magnetic layer is prepared on the piezoelectric substrate. The magnetic layer includes a convex body, which is used to divide the magnetic layer into bit regions and storage regions.

[0070] In step S720, a magnetic tunnel junction is prepared within the bit region of the magnetic layer.

[0071] In step S730, a first electrode and a second electrode are fabricated at both ends of the piezoelectric substrate.

[0072] In some embodiments, a heavy metal layer may also be fabricated between the piezoelectric substrate and the magnetic layer. The heavy metal layer can provide antisymmetric exchange coupling interactions to generate stable Nair-type skyrmions within the bit regions of the magnetic layer.

[0073] In the embodiments of this disclosure, a storage cell can be fabricated in a simple and efficient manner. This storage cell can be used to achieve low-power driving of skyrmions with no current in a pure electric field, thereby reducing the power consumption of the device. In addition, the convex design can avoid storage errors of information caused by the influence of the external environment on skyrmions, thereby improving the stability and non-volatility of the storage.

[0074] According to another aspect of this disclosure, an information storage method applied to a storage unit is also provided. The following will be combined with... Figure 8 The method is described in detail.

[0075] Figure 8 This is a flowchart of an information storage method according to an embodiment of the present disclosure.

[0076] like Figure 8As shown, the information storage method includes steps S810 to S820. Steps S810 to S820 can be executed for at least one storage cycle.

[0077] In step S810, a first current is applied to the magnetic tunnel junction to form a stable skyrmion in the bit region of the magnetic layer.

[0078] According to embodiments of this disclosure, the current direction of the first current may be perpendicular to the surface of the magnetic tunnel junction, so that the magnetic tunnel junction is polarized into a spin-polarized current, thereby forming a stable skyrmion in the bit region of the magnetic layer.

[0079] The term "skymion" as used here can refer to, for example, a Bloch-type skymion or a Nair-type skymion; this disclosure does not limit the specifics.

[0080] In this embodiment, a third current can be applied to the magnetic tunnel junction to detect whether a stable skyrmion has been formed in the bit region. If a stable skyrmion has been formed in the bit region, there is no need to continue generating skyrmions. Compared to track memories that require continuous skyrmion generation to write information, the solution disclosed herein has better stability and high repeatability, and reduces the power consumption of the device.

[0081] In step S820, a first voltage is applied to the first electrode and the second electrode to generate a first strain in the piezoelectric substrate. The first strain is transmitted to the magnetic layer through the heterojunction to drive skyrmions from the bit area of ​​the magnetic layer to the storage area of ​​the magnetic layer, thereby realizing the writing of the information to be stored.

[0082] According to embodiments of this disclosure, the position of a skyrmion on the magnetic layer can represent different bit states. For example, when a skyrmion is located in the storage region of the magnetic layer, it corresponds to a "1" bit state; when a skyrmion is located in the bit region of the magnetic layer, it corresponds to a "0" bit state. Therefore, information storage can be achieved by driving skyrmions to "shuttle back and forth" between different regions of the magnetic layer.

[0083] According to embodiments of this disclosure, the first voltage may be, for example, a positive voltage, which is the same as or similar to the definition described above, and will not be repeated here.

[0084] In some embodiments, a second voltage can be applied to the first electrode and the second electrode to generate a second strain in the piezoelectric substrate. The second strain is transmitted to the magnetic layer through the heterojunction to drive skyrmions from the storage region of the magnetic layer to the bit region of the magnetic layer, thereby erasing the information to be stored.

[0085] According to embodiments of this disclosure, the direction of the second voltage is opposite to the direction of the first voltage. For example, the second voltage may be a reverse voltage. The reverse voltage is the same as or similar to the definition described above, and will not be repeated here.

[0086] In some embodiments, a second current can be applied to the magnetic tunnel junction to read the resistance state information of the magnetic tunnel junction, thereby realizing the reading of the information to be stored.

[0087] According to embodiments of this disclosure, the speed at which skyrmions move between the bit region and the storage region of the magnetic layer is determined based on the voltage values ​​applied to the first and second electrodes. The speed of the skyrmions can be controlled by changing the magnitude of the voltage applied to the first and second electrodes, thereby achieving high access speeds.

[0088] According to another aspect of this disclosure, a memory is provided. This memory may include the memory cell described in any of the above embodiments, or may include a memory cell prepared using the preparation method of the memory cell described in any of the above embodiments.

[0089] It should be noted that the implementation methods, technical problems solved, functions achieved, and technical effects of each structure in the device embodiment are the same as or similar to the implementation methods, technical problems solved, functions achieved, and technical effects of each corresponding step in the method embodiment, and will not be repeated here.

[0090] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A storage unit, characterized in that, include: A piezoelectric substrate has a first electrode and a second electrode at its two ends. By applying a voltage to the first electrode and the second electrode, the piezoelectric substrate is subjected to strain under the action of an electric field. The strain is transmitted to the magnetic layer through the heterojunction to drive skyrmions to move on the magnetic layer, so as to achieve current-free driving of skyrmions. A magnetic layer, located on the surface of the piezoelectric substrate, forms a heterojunction with the piezoelectric substrate and is used to generate, stabilize and serve as the basic carrier for skyrmion motion. The magnetic layer includes a convex body that divides the magnetic layer into a bit region and a storage region. The bit region is provided with a magnetic tunnel junction for performing skymin generation and detection functions.

2. The storage unit according to claim 1, characterized in that, Current is injected in a direction perpendicular to the surface of the magnetic tunnel junction to induce the formation of stable skyrmions in the bit region.

3. The storage unit according to claim 2, characterized in that, The magnetic tunnel junction detects whether a skyrmion exists in the bit region based on the tunneling magnetoresistance effect. If it exists, it is recorded as a "0" bit state; otherwise, when the skyrmion is located in the storage region, it is recorded as a "1" bit state. When the skyrmion is located in the bit area, a first voltage is applied to the first electrode and the second electrode to drive the skyrmion to move from the bit area to the storage area, so as to realize the switching from "0" bit state to "1" bit state; When a second voltage is applied to the first electrode and the second electrode, the skyrmion is driven to move from the storage area to the bit area to achieve a switch from a "1" bit state to a "0" bit state, wherein the direction of the second voltage is opposite to the direction of the first voltage.

4. The storage cell according to any one of claims 1 to 3, characterized in that, The skyrmions move in the direction of increasing strain.

5. The storage unit according to claim 1, characterized in that, The piezoelectric substrate layer is made of one or more of the following materials: lead zirconate titanate, lead magnesium niobate titanate, La-BiFeO3, Sm-BiFeO3, and BaTiO3-BiMgTiO3.

6. The storage unit according to claim 1, characterized in that, The height of the convex body is higher than the height of the bit area and the storage area, so that when the skyrmion is confined to one area of ​​the magnetic layer, it will not move to another area due to disturbances in the external environment.

7. The storage unit according to claim 1, characterized in that, The magnetic layer is made of one or more of the following materials: Co, CoFeB, CoFe, and FeNi.

8. The storage unit according to claim 1, characterized in that, Also includes: A heavy metal layer, located between the piezoelectric substrate layer and the magnetic layer, is used to provide antisymmetric exchange coupling interaction.

9. The storage unit according to claim 8, characterized in that, The heavy metal layer is made of one or more of the following materials: W, Ta, Pt, Pd, Ph, Ir, Pb, and Au.

10. An information storage method, applied to the storage unit according to any one of claims 1 to 9, characterized in that, include: A first current is applied to the magnetic tunnel junction to form stable skyrmions in the bit region of the magnetic layer; as well as A first voltage is applied to the first electrode and the second electrode to generate a first strain in the piezoelectric substrate. The first strain is transmitted to the magnetic layer through the heterojunction to drive the skyrmions from the bit area of ​​the magnetic layer to the storage area of ​​the magnetic layer, thereby realizing the writing of the information to be stored.

11. The information storage method according to claim 10, characterized in that, The method further includes: A second voltage is applied to the first electrode and the second electrode to generate a second strain in the piezoelectric substrate. The second strain is transmitted to the magnetic layer through the heterojunction to drive the skyrmions from the storage region of the magnetic layer to the bit region of the magnetic layer, thereby erasing the information to be stored. The direction of the second voltage is opposite to the direction of the first voltage.

12. The information storage method according to claim 10, characterized in that, The method further includes: A second current is applied to the magnetic tunnel junction, and the resistance state information of the magnetic tunnel junction is read to realize the reading of the information to be stored.

13. The information storage method according to any one of claims 10 to 12, characterized in that, The speed at which the skyrmion moves between the bit region and the storage region of the magnetic layer is determined based on the voltage values ​​applied to the first and second electrodes.

14. The information storage method according to any one of claims 10 to 12, characterized in that, When the skyrmion is located in the storage area of ​​the magnetic layer, it corresponds to a "1" bit state; when the skyrmion is located in the bit area of ​​the magnetic layer, it corresponds to a "0" bit state.

15. A method for fabricating a memory cell, characterized in that, include: A magnetic layer is fabricated on a piezoelectric substrate; the magnetic layer includes a convex body for dividing the magnetic layer into a bit region and a storage region; A magnetic tunnel junction is fabricated within the bit region of the magnetic layer; and A first electrode and a second electrode are respectively fabricated at both ends of the piezoelectric substrate.

16. The method for fabricating a storage cell according to claim 15, characterized in that, Also includes: A heavy metal layer is prepared between the piezoelectric substrate layer and the magnetic layer.

17. A memory, characterized in that, include: The storage unit as described in any one of claims 1 to 9, or The storage cell is prepared by the method of preparing the storage cell as described in any one of claims 15 to 16.

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