Pinning structure and memory bit
By introducing a coupling-enhancing composite layer into the pinned structure, the strength of the RKKY coupling field is enhanced, the instability of the pinned layer is solved, and the stability of the pinned structure and the symmetry of the flip current are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2026-03-13
AI Technical Summary
In traditional MTJs, the pinned layers are not stable enough, causing the reference layer to easily flip under low magnetic fields, which cannot meet the requirements for high data retention time.
By introducing a coupling-enhancing composite layer into the pinned structure, the strength of the RKKY coupling field is increased, thereby improving the stability of the pinned structure.
It enhances the vertical magnetic anisotropy and stability of the pinned structure, reduces the influence of stray fields on the free layer, and improves the symmetry of the flip current.
Smart Images
Figure CN121665902A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of magnetic storage technology, and more particularly to a pinning structure and a storage bit. Background Technology
[0002] Magnetic RAM (MRAM) is a new generation of non-volatile memory, offering advantages such as radiation resistance, fast write speed, low write power consumption, and high write / erase cycles. First-generation magnetic RAM (Toggle-MRAM) writes information to bits at the intersection of word and bit lines by simultaneously applying current to both. Due to the spatial distribution of the magnetic field, bit density cannot be high to ensure accurate writing. Second-generation spin-transfer torque magnetic RAM (STT-MRAM) uses full current for writing, allowing for higher density and is currently the mainstream commercial magnetic RAM. Third-generation spin-orbit torque magnetic RAM (SOT-MRAM) applies current to the orbital layer, causing the free layers in the MTJ (magnetic tunnel junction) to magnetize and flip, thus writing information.
[0003] The structure of the pinning layer (SAF layer) in a traditional MTJ is: (Co / Pt)m / Ru / (Co / Pt)z, where m and z are the period numbers, Ru corresponds to the coupling layer, (Co / Pt)m is the first pinning sub-layer, and (Co / Pt)z is the second pinning sub-layer, as shown below. Figure 1 As shown, m is 3 and z is 4. MTJs with pinned layers of this structure often suffer from insufficient stability of the pinned layers, leading to easy flipping of the reference layer in the MTJ under lower magnetic fields, thus failing to meet the high data retention requirements. Specifically, when applying pinned layers to top-pinned MTs, the main reason for the insufficient stability of the pinned layers is that top pinning cannot use a sufficiently thick seed layer, resulting in the SAF layer failing to form a good (111) crystal structure, thus affecting its vertical anisotropy and leading to a weak RKKY (Ruderman-Kittel-Kasuya-Yosida) coupling field (H). ex ).
[0004] Therefore, improving the stability of the pinned layer has become an urgent problem to be solved. Summary of the Invention
[0005] To address the aforementioned issues, the pinning structure and storage bit provided by this invention increase the strength of the RKKY coupling field of the pinning structure by adding a coupling enhancement composite layer, thereby improving the stability of the pinning structure.
[0006] In a first aspect, the present invention provides a pinning structure comprising: a first pinning composite layer, a coupling enhancement composite layer, a coupling layer, and a second pinning composite layer stacked sequentially from bottom to top;
[0007] The first pinned composite layer includes at least one pinned stacked film, the pinned stacked film including a ferromagnetic layer and a non-magnetic metal layer stacked sequentially from bottom to top, the material of the ferromagnetic layer including at least one magnetic material, and the material of the non-magnetic metal layer including at least one non-magnetic heavy metal.
[0008] The coupling-enhanced composite layer includes at least one coupling stacked film, which includes a ferromagnetic layer, a coupling layer and at least one pinned stacked film stacked sequentially from bottom to top;
[0009] The second pinning composite layer includes at least one pinning stacked film.
[0010] Optionally, a ferromagnetic layer is bonded to the upper surface of the coupling-enhancing composite layer.
[0011] Optionally, the material of the coupling layer includes at least one of heavy metals that have the RKKY coupling effect.
[0012] Optionally, heavy metals exhibiting RKKY coupling effects include: Ru, Ir, Cr, Ta, Gd, Pt, Hf, Os, Rh, Nb, and Tb.
[0013] Alternatively, the magnetic material includes Co and CoFe.
[0014] Optionally, non-magnetic heavy metals include Pt and Pd.
[0015] Optionally, the pinning structure may also include an antiferromagnetic layer;
[0016] The antiferromagnetic layer is stacked on the lower surface of the first pinned composite layer or the upper surface of the second pinned composite layer.
[0017] In a second aspect, the present invention provides a storage bit, the storage bit comprising a pinning structure as described in any one of claims 1 to 7.
[0018] Optionally, the storage bits also include: an SOT orbital layer, a free layer, a barrier layer, a reference layer, a spacer layer, and a guard layer stacked from bottom to top;
[0019] The stapling structure is stacked between the spacer layer and the protective layer.
[0020] Optionally, the storage bit may also include: a seed layer, a spacer layer, a reference layer, a barrier layer, a free layer, and a protective layer;
[0021] The pinned structure is stacked between the seed layer and the spacer layer.
[0022] The pinning structure and storage bit provided in this embodiment of the invention, by setting a coupling enhancement composite layer between the first pinning composite layer and the coupling layer, facilitates the optimization of the pinning stack film, increases the strength of the RKKY coupling field of the pinning structure, and improves the vertical magnetic anisotropy of the pinning structure, thereby enhancing the stability of the pinning structure. Simultaneously, the pinning structure in the storage bit also reduces the influence of stray fields from the pinning structure on the static magnetic field of the free layer, making the overall static magnetic field distribution in the free layer more uniform and improving the symmetry of the switching current. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of the pinning layer structure in a traditional MTJ;
[0025] Figure 2 This is an illustration of a pinning structure according to an embodiment of this application;
[0026] Figure 3 This is a schematic diagram of the variation curve of the RKKY coupling strength of the coupling layer in an embodiment of this application;
[0027] Figure 4 This is a schematic structural diagram illustrating a simulated test structure when testing the bottom coupling layer in a coupling-enhanced composite layer, according to an embodiment of this application.
[0028] Figure 5 This is a schematic structural diagram illustrating a simulated test structure when testing the top coupling layer in a coupling-enhanced composite layer according to an embodiment of this application.
[0029] Figure 6 This is a schematic structural diagram illustrating a simulated test structure when testing the coupling layer above the coupling enhancement composite layer, according to an embodiment of this application.
[0030] Figure 7 This is a schematic structural diagram of a storage bit in an embodiment of this application;
[0031] Figure 8 This is a schematic structural diagram of a storage bit in an embodiment of this application;
[0032] Figure 9 This is a schematic diagram of the static magnetic field distribution of the pinning layer, the first pinning structure, and the second pinning structure at the free layer according to an embodiment of this application.
[0033] Figure 10 This is a schematic structural diagram of a storage bit in an embodiment of this application;
[0034] Figure 11 This is a schematic structural diagram of a storage bit in an embodiment of this application.
[0035] in, Figure 7 and Figure 8 These correspond to storage bits for two different top-pinned structures. Figure 8 The storage bits also include an antiferromagnetic layer; Figure 10 and Figure 11 These correspond to storage bits for two different bottom pinning structures. Figure 11 The storage bits also include an antiferromagnetic layer.
[0036] Figure label:
[0037] 1. First pinned composite layer; 2. Coupling-enhanced composite layer; 21. Coupling stacked film; 3. Coupling layer; 4. Second pinned composite layer; 51. Pinned stacked film; 511. Ferromagnetic layer; 512. Non-magnetic metal layer; 61. Free layer; 62. Barrier layer; 63. Reference layer; 64. Spacer layer; 65. Protective layer; 66. Antiferromagnetic layer; 67. Seed layer; 71. SOT orbital layer. Detailed Implementation
[0038] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.
[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
[0040] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.
[0041] It should be noted that when an element is referred to as "fixedly connected" to another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is referred to as being "directly on" another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.
[0042] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, step, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof.
[0043] Example 1
[0044] This embodiment provides a pinning structure, see [link / reference] Figure 2 The pinning structure includes: a first pinning composite layer 1, a coupling enhancement composite layer 2, a coupling layer 3, and a second pinning composite layer 4 stacked sequentially from bottom to top.
[0045] The first pinned composite layer 1 includes at least one pinned stacked film 51. The pinned stacked film 51 includes a ferromagnetic layer 511 and a non-magnetic metal layer 512 stacked sequentially from bottom to top. Each ferromagnetic layer 511 is made of at least one magnetic material; each non-magnetic metal layer 512 is made of at least one non-magnetic heavy metal. Magnetic materials include, but are not limited to, Co and CoFe. Non-magnetic heavy metals include, but are not limited to, Pt and Pd.
[0046] The coupling-enhanced composite layer 2 includes at least one coupling stacked film 21. The coupling stacked film 21 includes, from bottom to top, a ferromagnetic layer 511, a coupling layer 3, and at least one pinned stacked film 51. Each coupling layer 3 is made of at least one heavy metal exhibiting RKKY coupling effect. Heavy metals exhibiting RKKY coupling effect include, but are not limited to: Ru, Ir, Cr, Ta, Gd, Pt, Hf, Os, Rh, Nb, and Tb.
[0047] The second stapling composite layer 4 includes at least one stapling stacked film 51.
[0048] It is understandable that the thickness and material of the ferromagnetic layer 511 at different locations can be different or the same; the thickness and material of the non-magnetic metal layer 512 at different locations can be different or the same. Generally speaking, the thickness of each non-magnetic metal layer 512 is not less than the thickness of one atomic layer; the thickness and material of the coupling layer 3 at different locations can be different or the same. Similarly, the coupling stacked films 21 at different locations can contain the same number of pinned stacked films 51, or they can each contain different numbers of pinned stacked films 51.
[0049] Furthermore, the selection of the number 'a' of the pinned stacked films 51 in the first pinned composite layer 1, the selection of the number 'n' of the coupling stacked films 21 in the coupling enhancement composite layer 2, the selection of the number 'b' of the pinned stacked films 51 in each coupling stacked film 21, and the selection of the number 'c' of the pinned stacked films 51 in the second pinned composite layer 4 are all, as a whole, used to make the net magnetic moments of the pinned structures cancel each other out, and to make the total magnetic field generated by the pinned structures at the free layer 61 position close to zero or a certain set value, that is, the offset (cancellation) magnetic field of the MTJ close to zero or a certain set value. Here, a, b, c, and n are all integers greater than or equal to 1, and correspond to the number of cycles in each structure, respectively. The adjustment of the offset magnetic field can be achieved by changing the above number of cycles, or by adjusting the thickness of the pinned stacked films 51 in the pinned structure.
[0050] In this process, both the coupling layer 3 in the coupling enhancement composite layer 2 and the coupling layer 3 outside the coupling enhancement composite layer 2 can align the surface atoms of the ferromagnetic layer 511 that is attached to it with the surface atoms of the adjacent coupling layer 3 when exposed to a magnetic field, thereby pinning the orientation of the magnetic moments of each layer in the first pinning composite layer 1 and the second pinning composite layer 4.
[0051] In this embodiment, the first pinning composite layer 1 includes two pinning stacked films 51, the coupling enhancement composite layer 2 includes two coupling stacked films 21, each coupling stacked film 21 includes a ferromagnetic layer 511, a coupling layer 3 and a pinning stacked film 51, and the second pinning composite layer 4 includes two pinning stacked films 51.
[0052] Meanwhile, in this embodiment, the ferromagnetic layer 511 at different locations in the pinning structure is made of the same material, the non-magnetic metal layer 512 at different locations in the pinning structure is made of the same material, and the coupling layer 3 at different locations in the pinning structure is made of the same material.
[0053] In addition, in this embodiment, a ferromagnetic layer 511 is attached to the upper surface of the coupling enhancement composite layer 2, and the upper surface of the ferromagnetic layer 511 attached to the upper surface of the coupling enhancement composite layer 2 is attached to the lower surface of the coupling layer 3.
[0054] By attaching a ferromagnetic layer 511 to the upper surface of the coupling enhancement composite layer 2, the stability of the connection between the coupling enhancement composite layer 2 and the coupling layer 3 can be enhanced.
[0055] Whether it is the coupling layer 3 in the coupling enhancement composite layer 2 or the coupling layer 3 outside the coupling enhancement composite layer 2, its thickness can be the thickness of the coupling layer 3 corresponding to the first antiferromagnetic coupling peak or the second antiferromagnetic coupling peak.
[0056] The method for determining the thickness of the coupling layer 3 corresponding to the first and second antiferromagnetic coupling peaks is as follows: all coupling layers 3 used in this invention are individually stacked with other pinned stacked films 51 in the pinned structure to obtain a simulated test structure. During the RKKY coupling strength test, the change curve of the RKKY coupling strength of the coupling layer 3 can be obtained by adjusting the thickness of the coupling layer 3 in the simulated test structure. Figure 3 The curve shows the variation of the RKKY coupling strength of coupling layer 3, where X0 is the thickness of coupling layer 3 corresponding to the first antiferromagnetic coupling peak, and X1 is the thickness of coupling layer 3 corresponding to the second antiferromagnetic coupling peak.
[0057] Then, the thickness of the coupling layer 3 at the first or second antiferromagnetic coupling peak can be determined according to the corresponding change curve. When preparing the pinning structure in this invention, the coupling layer 3 at the corresponding position can be the thickness corresponding to the first or second antiferromagnetic coupling peak on the corresponding change curve.
[0058] Specifically, the method for forming the simulated test structure is as follows: taking the RKKY coupling strength (JRKKY)-thickness test of the pinned structure in this embodiment as an example, when testing the bottom coupling layer 3 in the coupling enhancement composite layer 2, the simulated test structure is the structure after removing the other coupling layers 3 in the pinned structure, as well as the ferromagnetic layer 511 that does not form the pinned stacked film 51, such as... Figure 4When testing the top coupling layer 3 in the coupling-enhancing composite layer 2, the simulated test structure is the structure after removing the other coupling layers 3 in the pinning structure, as well as the ferromagnetic layer 511 that does not form the pinned stacked film 51, such as... Figure 5 Similarly, when testing the coupling layer 3 above the coupling-enhancing composite layer 2, the simulated test structure is the structure after removing the other coupling layers 3 in the pinning structure, as well as the ferromagnetic layer 511 that does not form the pinned stacked film 51, such as... Figure 6 .
[0059] In this embodiment, the specific materials and thicknesses of each layer in the stapled structure are not specifically limited.
[0060] The pinning structure and storage bit provided in this embodiment of the invention, by setting a coupling enhancement composite layer 2 between the first pinning composite layer 1 and the coupling layer 3, is beneficial to optimizing the pinning stack film 51, while increasing the strength of the RKKY coupling field of the pinning structure and improving the vertical magnetic anisotropy of the pinning structure, thereby improving the stability of the pinning structure.
[0061] In a further optional embodiment of this embodiment, a ferromagnetic layer 511 is also attached to the upper surface of the second pinning layer composite layer.
[0062] Example 2
[0063] This embodiment provides a pinning structure, wherein the pinning structure provided in this embodiment differs from the pinning structures in Embodiment 1 or 2 in that: [the structure is combined with...] Figure 11 The pinning structure also includes an antiferromagnetic layer 66; the antiferromagnetic layer 66 is stacked on the lower surface of the first pinning composite layer 1 and adheres to the lower surface of the first pinning composite layer 1.
[0064] By forming an antiferromagnetic layer 66 on the lower surface of the first pinning composite layer 1, the stability of the pinning structure can be enhanced, thereby improving the stability of the flipping magnetic field of the corresponding free layer 61 and making the pinning structure suitable for bottom-pinned MTJs. At the same time, by introducing the antiferromagnetic layer 66, the performance of the pinned stacked film 51 can be improved, giving it stronger vertical anisotropy.
[0065] Example 3
[0066] This embodiment provides a pinning structure, wherein the pinning structure provided in this embodiment differs from the pinning structure in Embodiment 1 in that: [the structure is combined with...] Figure 8 The pinning structure also includes an antiferromagnetic layer 66; the antiferromagnetic layer 66 is stacked on the upper surface of the second pinning composite layer 4 and adheres to the upper surface of the second pinning composite layer 4.
[0067] By forming an antiferromagnetic layer 66 on the upper surface of the second pinning composite layer 4, the stability of the pinning structure can be enhanced, thereby improving the stability of the flipping magnetic field of the corresponding free layer 61 and making the pinning structure suitable for top-pinned MTJs.
[0068] Example 4
[0069] This embodiment provides a pinning structure, wherein the pinning structure provided in this embodiment differs from the pinning structures in Embodiment 1 or 2 in that: [the structure is combined with...] Figure 10 The pinning structure also includes a seed layer 67, which is stacked below the pinning structure as in Example 1 or 2. The seed layer 67 is used to improve the adhesion and seeding of subsequently deposited layers in the MTJ.
[0070] Wherein, when the seed layer 67 is stacked below the pinning structure as in Example 2, combined with Figure 11 The upper surface of the seed layer 67 is attached to the lower surface of the antiferromagnetic layer 66, and the upper surface of the antiferromagnetic layer 66 is attached to the lower surface of the pinning structure in Example 2.
[0071] By forming a seed layer 67, a good (111) crystal structure can be formed in the pinned structure, thereby improving the vertical magnetic anisotropy of the pinned structure and increasing the strength of the RKKY coupling field (Hex) of the pinned structure.
[0072] Example 5
[0073] This embodiment provides a storage bit, which includes a top-pinned magnetic tunnel junction, the magnetic tunnel junction including the pinning structure as in any one of Embodiments 1 and 3.
[0074] In this embodiment, the magnetic tunnel junction includes the pinning structure of Embodiment 1.
[0075] In a further optional embodiment of this embodiment, combined with Figure 7 or Figure 8 The magnetic tunnel junction also includes: a free layer 61, a barrier layer 62, a reference layer 63, a spacer layer 64, and a protective layer 65 stacked from bottom to top; and a pinned structure stacked between the spacer layer 64 and the protective layer 65.
[0076] The storage bits also include: SOT track layer 71. The upper surface of SOT track layer 71 is attached to the lower surface of free layer 61.
[0077] The storage bit provided in this embodiment increases the strength of the RKKY coupling field of the pinned structure by setting a coupling enhancement composite layer 2 between the first pinning composite layer 1 and the coupling layer 3. Furthermore, multiple coupling layers 3 can provide a structural seed layer 67 for each pinned stack film 51, improving the vertical magnetic anisotropy of the pinned structure and thus enhancing its stability. Simultaneously, the pinning structure in this storage bit also improves the flexibility of adjusting the pinned stack film 51, reduces the influence of stray fields from the pinned structure on the static magnetic field of the free layer 61, and makes the overall static magnetic field distribution in the free layer 61 more uniform, thereby improving the symmetry of the switching current.
[0078] Specifically, for Figure 1 The static magnetic field distribution at the free layer 61 is compared among the pinning layer with a single-layer coupling layer 3, the first pinning structure, and the second pinning structure. The second pinning structure is the pinning structure in Example 1, and the first pinning structure is the structure in Example 1 where the coupling-enhancing composite layer 2 contains only one layer of coupling stacked film 21. In the pinning layer with a single-layer coupling layer 3, the thickness of the pinning multilayer below the coupling layer 3 is 2 nanometers, and the thickness of the pinning multilayer above the coupling layer 3 is 4 nanometers. In the first pinning structure, the total thickness of the multiple pinning stacked films 51 below the bottom coupling layer 3 is 2 nanometers. The total thickness of the multiple pinned stacked films 51 between the coupling layer 3 and the top coupling layer 3 is 6 nanometers, and the total thickness of the multiple pinned stacked films 51 above the top coupling layer 3 is 2 nanometers; in the second pinning structure, the total thickness of the multiple pinned stacked films 51 below the bottom coupling layer 3 is 1 nanometer, the total thickness of the multiple pinned stacked films 51 between the bottom coupling layer 3 and the lower middle coupling layer 3 is 5 nanometers, the total thickness of the multiple pinned stacked films 51 between the top coupling layer 3 and the upper middle coupling layer 3 is 4 nanometers, and the total thickness of the multiple pinned stacked films 51 above the top coupling layer 3 is 2 nanometers.
[0079] Combination Figure 9 It can be seen that, Figure 9 The distance 0 in the middle is the geometric center of the free layer 61. As the number of coupling layers 3 increases, the static magnetic field distribution at the free layer 61 becomes more uniform and the stray field becomes smaller.
[0080] Example 6
[0081] This embodiment provides a storage bit, which includes a bottom-pinned magnetic tunnel junction, the magnetic tunnel junction including the pinning structure as in any one of embodiments 1, 2 and 4.
[0082] In a further optional embodiment of this embodiment, combined with Figure 10 or Figure 11The magnetic tunnel junction also includes: a spacer layer 64, a reference layer 63, a barrier layer 62, a free layer 61, and a protective layer 65 stacked from bottom to top; the upper surface of the pinned structure is attached to the lower surface of the spacer layer 64.
[0083] The storage bits provided in this embodiment reduce the influence of the static magnetic field of the pinned structure on the free layer 61 through multiple coupling layers 3, especially reducing the static magnetic field at the edge of the free layer 61, making its overall static magnetic field distribution more uniform and improving the symmetry of the STT (spin-transfer torque) flip-flop current. At the same time, by introducing an antiferromagnetic layer 66, the pinned stack film 51 is improved, giving it stronger vertical anisotropy.
[0084] In the description of this specification, the references to terms such as "some embodiments," "other embodiments," "ideal embodiments," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example that are included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.
[0085] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0086] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A pinning structure, characterized in that, The pinning structure includes: a first pinning composite layer (1), a coupling enhancement composite layer (2), a coupling layer (3), and a second pinning composite layer (4) stacked sequentially from bottom to top; The first pinned composite layer (1) includes at least one pinned stacked film (51), the pinned stacked film (51) includes a ferromagnetic layer (511) and a non-magnetic metal layer (512) stacked sequentially from bottom to top, the material of the ferromagnetic layer (511) includes at least one magnetic material, and the material of the non-magnetic metal layer (512) includes at least one non-magnetic heavy metal. The coupling enhancement composite layer (2) includes at least one coupling stack film (21), which includes the ferromagnetic layer (511), the coupling layer (3) and at least one pinned stack film (51) stacked from bottom to top. The second pinning composite layer (4) includes at least one layer of the pinning stack film (51).
2. The pinning structure according to claim 1, characterized in that, The upper surface of the coupling enhancement composite layer (2) is bonded with a layer of the ferromagnetic layer (511).
3. The pinning structure according to claim 1, characterized in that, The material of the coupling layer (3) includes at least one of the heavy metals that have the RKKY coupling effect.
4. The pinning structure according to claim 3, characterized in that, The heavy metals exhibiting the RKKY coupling effect include: Ru, Ir, Cr, Ta, Gd, Pt, Hf, Os, Rh, Nb, and Tb.
5. The pinning structure according to claim 1, characterized in that, The magnetic materials include Co and CoFe.
6. The pinning structure according to claim 1, characterized in that, The non-magnetic heavy metals include Pt and Pd.
7. The pinning structure according to any one of claims 1 to 6, characterized in that, The pinning structure also includes an antiferromagnetic layer (66); The antiferromagnetic layer (66) is stacked on the lower surface of the first pinned composite layer (1) or the upper surface of the second pinned composite layer (4).
8. A storage bit, characterized in that, The storage bit includes the pinning structure as described in any one of claims 1 to 7.
9. The storage bit according to claim 8, characterized in that, The storage bit also includes: an SOT orbital layer (71), a free layer (61), a barrier layer (62), a reference layer (63), a spacer layer (64), and a protective layer (65) stacked from bottom to top; The pinning structure is stacked between the spacer layer (64) and the protective layer (65).
10. The storage bit according to claim 8, characterized in that, The storage bit further includes: a seed layer (67), a spacer layer (64), a reference layer (63), a barrier layer (62), a free layer (61), and a protective layer (65); The pinning structure is stacked between the seed layer (67) and the spacer layer (64).