Wide-range TMR sensor tunnel junction based on artificial antiferromagnetic free layer and sensor

Abstract

The invention discloses a wide-range TMR sensor tunnel junction based on an artificial antiferromagnetic free layer and a sensor, the wide-range TMR sensor tunnel junction comprises a seed layer, a first antiferromagnetic layer, a sandwich structure body and a cap layer on a substrate, the sandwich structure body comprises the artificial antiferromagnetic free layer, an insulation barrier layer and a pinning layer, the artificial antiferromagnetic free layer is composed of an artificial antiferromagnetic structure and a free ferromagnetic layer, the artificial antiferromagnetic structure is used for pinning the magnetic moment direction of the free ferromagnetic layer, and the pinning layer is used for pinning the magnetic moment direction of the reference ferromagnetic layer by using the artificial antiferromagnetic structure; the pinning directions of the artificial antiferromagnetic free layer and the pinning layer are perpendicular to each other, so that the artificial antiferromagnetic free layer has perpendicular magnetic anisotropy, and the pinning effect of the artificial antiferromagnetic free layer is weaker than that of the pinning layer. The invention aims to solve the problems that an existing TMR sensor is small in measuring range, narrow in working interval and difficult to meet large-range magnetic field measurement such as a smart power grid and magnetic anomaly detection from the aspect of thin film materials.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic sensors, and particularly relates to a wide-range TMR sensor tunnel junction and sensor based on an artificial antiferromagnetic free layer. Background Art

[0002] A tunneling magnetoresistance (TMR) sensor is a magnetic sensor constructed with a magnetic tunnel junction as the core. It has advantages such as high sensitivity, low power consumption, miniaturization, high stability, and high integration, and has broad application prospects in many fields such as smart power grids, biomedicine, magnetic anomaly detection, and weaponry. At the same time, as a spintronic device, TMR has the potential for realizing the integration of sensing, storage, and computing. Due to the limitation of the low saturation magnetic field of magnetic materials, traditional TMR magnetic sensors generally have problems of low range and narrow working area, restricting their application scenarios. To solve this problem, theoretically, the range of the magnetic sensor can be further expanded by finding a tunnel junction ferromagnetic material with a high saturation field, but it is difficult to ensure that the tunnel junction still has a high TMR effect when changing materials. Secondly, the range of the tunnel junction can also be adjusted by applying a perpendicular bias magnetic field. However, in existing methods, permanent magnetic materials are mostly used to provide the bias magnetic field, and the magnetism of permanent magnetic materials will undergo an irreversible transformation in a large external magnetic field environment. In addition, the volume of such bias magnets is relatively large, which is not conducive to the processing and integration of TMR sensor chips. In addition, the range can also be expanded by adjusting the shape and structure of the free layer and reference layer in the TMR sensor. For example, a vortex-structured free layer is used, but the processing technology of these methods is difficult and it is difficult to achieve mass production. Summary of the Invention

[0003] The technical problem to be solved by the present invention: Aiming at the above problems of the prior art, a wide-range TMR sensor tunnel junction and sensor based on an artificial antiferromagnetic free layer are provided. The present invention aims to solve the problems that the existing TMR sensors have a small range and a narrow working range and are difficult to meet the requirements of large-range magnetic field measurements such as smart power grids and magnetic anomaly detection from the thin film material level.

[0004] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A wide-range TMR sensor tunnel junction based on an artificial antiferromagnetic free layer, comprising a substrate and a seed layer, a first antiferromagnetic layer, a sandwich structure, and a capping layer that are sequentially stacked on the substrate. The sandwich structure includes an artificial antiferromagnetic free layer, an insulating barrier layer, and a pinned layer that are sequentially stacked from top to bottom. The artificial antiferromagnetic free layer is composed of an artificial synthetic antiferromagnetic structure and a free ferromagnetic layer to pin the magnetic moment direction of its free ferromagnetic layer using the artificial synthetic antiferromagnetic structure. The pinned layer is composed of an artificial synthetic antiferromagnetic structure and a reference ferromagnetic layer to pin the magnetic moment direction of its reference ferromagnetic layer using the artificial synthetic antiferromagnetic structure. The pinned layer forms an exchange coupling with the first antiferromagnetic layer to achieve a stronger pinning effect. The pinning directions of the artificial antiferromagnetic free layer and the pinned layer are perpendicular to each other in the stacking plane, so that the reference ferromagnetic layer and the free ferromagnetic layer have mutually perpendicular magnetic anisotropies. The pinning effect in the artificial antiferromagnetic free layer is weaker than that in the pinned layer, so that the two have different coercive forces.

[0005] Optionally, the artificial synthetic antiferromagnetic structure in the artificial antiferromagnetic free layer includes a first non-magnetic material layer and a first ferromagnetic material layer that are sequentially stacked from bottom to top, and the first non-magnetic material layer is stacked on the upper side of the free ferromagnetic layer, so that an antiferromagnetic coupling is formed between the first ferromagnetic material layer and the free ferromagnetic layer to pin the magnetic moment direction of the free ferromagnetic layer.

[0006] Optionally, the thickness of the first non-magnetic material layer is used to adjust the strength of the antiferromagnetic coupling formed between the first ferromagnetic material layer and the free ferromagnetic layer and to inhibit atomic diffusion. The calculation function expression of the free energy of the artificial antiferromagnetic free layer is: , In the above formula, is the free energy of the artificial antiferromagnetic free layer, is the anisotropy constant, is the thickness of the first ferromagnetic material layer, is the angle between the magnetic moment direction of the free ferromagnetic layer and the magnetic moment direction of the reference ferromagnetic layer. This angle is the angle between the magnetic moment direction of the free ferromagnetic layer and the magnetic moment direction of the reference ferromagnetic layer. is the thickness of the artificial antiferromagnetic free layer, is the external magnetic field, is the magnetization of the free ferromagnetic layer, is the interlayer exchange coupling constant between the free ferromagnetic layer and the first ferromagnetic material layer.

[0007] Optionally, the calculation function expression of the angle is: , In the above formula, is the equivalent anisotropy field, is the interlayer exchange coupling field.

[0008] Optionally, the artificial synthetic antiferromagnetic structure in the artificial antiferromagnetic free layer includes a first non-magnetic material layer, a first ferromagnetic material layer, a second non-magnetic material layer, and a second ferromagnetic material layer that are stacked in sequence from bottom to top, and the first non-magnetic material layer is stacked on the upper side of the free ferromagnetic layer, so that an antiferromagnetic coupling is formed between the first ferromagnetic material layer and the second ferromagnetic material layer and the magnetic moment direction of the free ferromagnetic layer is pinned.

[0009] Optionally, the artificial synthetic antiferromagnetic structure in the pinning layer is composed of a third non-magnetic material layer and a third ferromagnetic material layer that are stacked in sequence from top to bottom, and the third non-magnetic material layer is stacked on the lower side of the reference ferromagnetic layer.

[0010] Optionally, a second antiferromagnetic layer is clamped between the sandwich structure body and the capping layer.

[0011] Optionally, the calculation function expression of the tunnel junction resistance value of the wide-range TMR sensor tunnel junction is: , In the above formula, is the tunnel junction resistance value of the wide-range TMR sensor tunnel junction, and are respectively the parallel state resistance value and the antiparallel state resistance value of the wide-range TMR sensor tunnel junction, is the external magnetic field, is the equivalent anisotropy field, is the interlayer exchange coupling field, is the anisotropy constant, is the magnetization intensity of the free ferromagnetic layer, is the interlayer exchange coupling constant between the free ferromagnetic layer and the first ferromagnetic material layer, and the interlayer exchange coupling field makes the change of the tunnel junction resistance value decrease within a certain range of external magnetic field change to realize the expansion of the tunnel junction measurement range.

[0012] Optionally, the free ferromagnetic layer is made of Co 20 Fe 60 B 20 material, the first non-magnetic material layer is made of Ru material, the first ferromagnetic material layer is made of Co 20 Fe 60 B 20 material, the reference ferromagnetic layer is made of Co 40 Fe 40 B 20is made of a material, the third non-magnetic material layer is made of Ru material, and the third ferromagnetic material layer is made of Co 70 Fe 30 is made of a material, where the subscripts of each element in the material represent the mass percentage of the corresponding element.

[0013] In addition, the present invention also provides a sensor, including a sensor body and a TMR sensor tunnel junction disposed in the sensor body, and the TMR sensor tunnel junction is the wide-range TMR sensor tunnel junction based on an artificial antiferromagnetic free layer.

[0014] Compared with the prior art, the present invention mainly has the following beneficial effects: 1. The wide-range TMR sensor tunnel junction based on an artificial antiferromagnetic free layer of the present invention uses an artificial synthetic antiferromagnetic structure to softly pin the free ferromagnetic layer, realizing the regulation of the dynamic response range of the tunnel junction, so that the TMR sensor has a wider measurement range, and thus can solve the problems of small measurement range and narrow working range of existing TMR sensors from the thin film material level, and it is difficult to meet the requirements of large-range magnetic field measurements such as smart power grids and magnetic anomaly detection.

[0015] 2. The wide-range TMR sensor based on an artificial antiferromagnetic free layer of the present invention can be prepared by existing micro-nano processing methods such as deposition, photolithography, and etching, and is compatible with the CMOS processing process, facilitating processing and integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is an example of a frame structure of the wide-range TMR sensor tunnel junction in Embodiment 1 of the present invention.

[0017] Figure 2 is a schematic diagram of the magnetic moment orientation of the sandwich structure in Embodiment 1 of the present invention.

[0018] Figure 3 is an example of a detailed implementation structure of the wide-range TMR sensor tunnel junction in Embodiment 1 of the present invention.

[0019] Figure 4 is an example of a detailed implementation structure of the wide-range TMR sensor tunnel junction in Embodiment 2 of the present invention.

[0020] Figure 5 is an example of the frame structure of the wide-range TMR sensor tunnel junction in Embodiment 3 of the present invention.

[0021] Figure 6 is an example of a detailed implementation structure of the wide-range TMR sensor tunnel junction in Embodiment 3 of the present invention.

[0022] Legend: 1. Substrate; 2. Seed layer; 3. First antiferromagnetic layer; 4. Sandwich structure; 41. Pinned layer; 411. Reference ferromagnetic layer; 412. Third non-magnetic material layer; 413. Third ferromagnetic material layer; 42. Insulating barrier layer; 43. Artificial antiferromagnetic free layer; 431. Free ferromagnetic layer; 432. First non-magnetic material layer; 433. First ferromagnetic material layer; 434. Second non-magnetic material layer; 435. Second ferromagnetic material layer; 5. Capping layer; 6. Second antiferromagnetic layer. Detailed implementation

[0023] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings in the embodiments of the present invention.

[0024] Embodiment 1: As Figure 1 shown, this embodiment is based on a wide-range TMR sensor tunnel junction of an artificial antiferromagnetic free layer, including a substrate 1 and a seed layer 2, a first antiferromagnetic layer 3, a sandwich structure 4, and a capping layer 5 that are sequentially stacked on the substrate 1. The sandwich structure 4 includes an artificial antiferromagnetic free layer 43, an insulating barrier layer 42, and a pinned layer 41 that are sequentially stacked from top to bottom. The artificial antiferromagnetic free layer 43 is composed of an artificial synthetic antiferromagnetic structure and a free ferromagnetic layer 431 to pin the magnetic moment direction of its free ferromagnetic layer 431 by using the artificial synthetic antiferromagnetic structure. The pinned layer 41 is composed of an artificial synthetic antiferromagnetic structure and a reference ferromagnetic layer 411 to pin the magnetic moment direction of its reference ferromagnetic layer 411 by using the artificial synthetic antiferromagnetic structure. The pinned layer 41 and the first antiferromagnetic layer 3 form an exchange coupling to achieve a stronger pinning effect. The pinning directions of the artificial antiferromagnetic free layer 43 and the pinned layer 41 are perpendicular to each other in the stacking plane, so that the reference ferromagnetic layer 411 and the free ferromagnetic layer 431 have perpendicular magnetic anisotropy. The pinning effect in the artificial antiferromagnetic free layer 43 is weaker than that of the pinned layer 41, so that the two have different coercive forces.

[0025] As Figure 2 shown, in a zero magnetic field environment, the magnetic moment directions of the two magnetic layers of the pinned layer 41 and the artificial antiferromagnetic free layer 43 are perpendicular to each other in the stacking plane and have perpendicular magnetic anisotropy. Among them, the pinning direction of the artificial antiferromagnetic free layer 43 " " is represented as the front - to - back direction, and the arrow of the pinning layer 41 indicates that the pinning direction is the left - to - right direction. When an external magnetic field is applied, due to the strong pinning effect, the magnetic moment direction of the pinning layer 41 remains basically unchanged, while the magnetic moment direction of the artificial antiferromagnetic free layer 43 changes with the external magnetic field. The change in the relative magnetic moment direction between the two causes a change in the resistance value of the tunneling magnetoresistance. Since the artificial antiferromagnetic free layer 43 introduces the interlayer exchange coupling energy, compared with the tunneling junction of traditional TMR sensors, the change in the relative magnetic moment direction caused by the external magnetic field is smaller, and the change in the tunneling magnetoresistance shown is smaller. That is, when the resistance values in the parallel state and the antiparallel state are certain, the dynamic range of the tunneling junction of the TMR sensor to sense the change in the external magnetic field is expanded, achieving the purpose of broadening the measurement range of the TMR sensor and solving the problems of the small measurement range and narrow working range of traditional TMR sensors.

[0026] As Figure 3 shown, the bottom of the tunneling junction is the substrate 1. In this embodiment, the substrate 1 is made of silicon (Si) and its surface is covered with a silicon dioxide oxide layer (SiOx), so it is represented as Si / SiOx in Figure 3 . The seed layer 2 can enhance the bonding force between the magnetic thin film and the substrate 1, induce the formation of a specific orientation of the magnetic layer, facilitate obtaining a larger magnetoresistance effect, and lay the foundation for the formation of exchange bias. Refer to Figure 3 , as an optional implementation manner, in this embodiment, the seed layer 2 includes Ta layer, Ru layer, Ta layer, and Ru layer stacked in sequence from bottom to top, with thicknesses of 5 nm, 15 nm, 5 nm, and 5 nm respectively.

[0027] The first antiferromagnetic layer 3 can be made of IrMn material or PtMn material. For example, in this embodiment, the first antiferromagnetic layer 3 is made of IrMn material, specifically Ir 80 Mn 20 material, where the subscript of each element in the material represents the mass percentage of the corresponding element. For example, in Ir 80 Mn 20 material, the mass percentage of the Ir element is 80%, and the mass percentage of the Mn element is 20%. It should be noted that this mass percentage can be adjusted as needed.

[0028] As Figure 3As shown, in this embodiment, the synthetic antiferromagnetic structure in the pinning layer 41 is composed of a third non-magnetic material layer 412 and a third ferromagnetic material layer 413 that are stacked in sequence from top to bottom. The third non-magnetic material layer 412 is stacked below the reference ferromagnetic layer 411. The reference ferromagnetic layer 411 and the third ferromagnetic material layer 413 form an antiferromagnetic coupling, so that the magnetic moment of the reference ferromagnetic layer 411 is pinned. The pinning layer 41 also realizes the pinning effect through exchange coupling, but has a stronger exchange coupling field than the artificial antiferromagnetic free layer 43. Therefore, the pinning effect is more significant. During the change of the external magnetic field, an exchange coupling is formed between the first antiferromagnetic layer 3 and the pinning layer 41 to achieve exchange bias, ensuring that the magnetic moment of the reference ferromagnetic layer 411 does not rotate or only rotates slightly when measuring the external magnetic field. As Figure 1 shown, a first antiferromagnetic layer 3 is provided below the pinning layer 41, which can form an exchange coupling with the pinning layer 41 to achieve exchange bias and pin the magnetic moment orientation of the pinning layer 41 in a fixed direction.

[0029] The reference ferromagnetic layer 411 is made of ferromagnetic material. For example, as an alternative embodiment, as Figure 3 shown, in this embodiment, the reference ferromagnetic layer 411 is made of Co 40 Fe 40 B 20 material, with a thickness of 1.5 nm; The third non-magnetic material layer 412 is made of non-magnetic material. For example, as an alternative embodiment, as Figure 3 shown, in this embodiment, the third non-magnetic material layer 412 is made of Ru material, with a thickness of 0.8 nm.

[0030] The third ferromagnetic material layer 413 and the reference ferromagnetic layer 411 are made of ferromagnetic material. For example, as an alternative embodiment, as Figure 3 shown, in this embodiment, the third ferromagnetic material layer 413 is made of Co 70 Fe 30 material, with a thickness of 1.7 nm.

[0031] The insulating barrier layer 42 can be made of metal oxide material. Metal oxide is the key to generating the quantum tunneling effect. To ensure a high TMR effect, the thickness of the material layer is usually about 1-3 nm. The metal oxide material can be MgO or AlOx and other oxides. For example, as an alternative embodiment, as Figure 3 shown, in this embodiment, the insulating barrier layer 42 is made of MgO material layer, and the thickness is 1 nm. See Figure 3 .

[0032] In this embodiment, the artificial antiferromagnetic free layer 43 includes a first non-magnetic material layer 432 and a first ferromagnetic material layer 433 which are stacked in sequence from bottom to top. The first non-magnetic material layer 432 is stacked on the upper side of the free ferromagnetic layer 431, so that an antiferromagnetic coupling is formed between the first ferromagnetic material layer 433 and the free ferromagnetic layer 431 to pin the direction of the magnetic moment of the free ferromagnetic layer 431. The artificial antiferromagnetic free layer 43 uses the antiferromagnetic coupling generated by the artificial synthetic antiferromagnetic structure to softly pin the free ferromagnetic layer 431 therein, and uses the interlayer exchange coupling energy to reduce the change in the direction of the magnetic moment in the free ferromagnetic layer 431 caused by the change in the external magnetic field.

[0033] The free ferromagnetic layer 431 is made of ferromagnetic material. In this embodiment, the free ferromagnetic layer 431 uses CoFeB material, and its thickness X is usually in the range of 1-2 nm. See Figure 3 , as an alternative embodiment, the free ferromagnetic layer 431 in this embodiment uses Co 20 Fe 60 B 20 material.

[0034] In this embodiment, the first non-magnetic material layer 432 is made of Ru material. In addition to forming the artificial synthetic antiferromagnetic structure, the Ru material layer also has the function of preventing atomic diffusion.

[0035] The first ferromagnetic material layer 433 is made of ferromagnetic material. In this embodiment, the first ferromagnetic material layer 433 uses CoFeB material. See Figure 3 , as an alternative embodiment, the first ferromagnetic material layer 433 in this embodiment uses Co 20 Fe 60 B 20 material, and its thickness X is usually in the range of 1-2 nm.

[0036] As Figure 3 shown, in this embodiment, the capping layer 5 includes a Ta material layer and a Ru material layer which are stacked in sequence from bottom to top. As an alternative embodiment, the thickness of the Ta material layer in this embodiment is 5 nm, and the thickness of the Ru material layer is 10 nm.

[0037] In this embodiment, the thickness of the first non-magnetic material layer 432 is used to adjust the strength of the antiferromagnetic coupling formed between the first ferromagnetic material layer 433 and the free ferromagnetic layer 431 and to inhibit atomic diffusion. The calculation function expression of the free energy of the artificial antiferromagnetic free layer 43 is: , In the above formula, is the free energy of the artificial antiferromagnetic free layer 43, is the anisotropy constant, is the thickness of the first ferromagnetic material layer 433, is the angle between the magnetic moment direction of the free ferromagnetic layer 431 and the anisotropy axis direction of the reference ferromagnetic layer 411, is the thickness of the artificial antiferromagnetic free layer 43, is the external magnetic field, is the magnetization of the free ferromagnetic layer 431, is the interlayer exchange coupling constant between the free ferromagnetic layer 431 and the first ferromagnetic material layer 433. Among them, since the magnetic moment direction of the reference ferromagnetic layer 411 in the pinning layer 41 is pinned to be consistent with the anisotropy axis direction, that is, the angle between the magnetic moment direction of the free ferromagnetic layer 431 and the magnetic moment direction of the reference ferromagnetic layer 411. In this embodiment, the calculation function expression of this angle is: , In the above formula, is the equivalent anisotropy field, is the interlayer exchange coupling field.

[0038] In this embodiment, the calculation function expression of the tunnel junction resistance of the wide-range TMR sensor tunnel junction is: , In the above formula, is the tunnel junction resistance of the wide-range TMR sensor tunnel junction, and are the parallel state resistance and the antiparallel state resistance of the wide-range TMR sensor tunnel junction respectively, is the external magnetic field, is the equivalent anisotropy field, is the interlayer exchange coupling field, is the anisotropy constant, is the magnetization of the free ferromagnetic layer 431, is the interlayer exchange coupling constant between the free ferromagnetic layer 431 and the first ferromagnetic material layer 433. This function expression expresses the relationship between the tunnel junction resistance and the external magnetic field The interlayer exchange coupling field in the function reduces the change of the tunnel junction resistance within a certain range of external magnetic field change to realize the expansion of the tunnel junction measurement range.

[0039] In addition, this embodiment also provides a sensor, including a sensor body and a TMR sensor tunnel junction disposed in the sensor body. The TMR sensor tunnel junction is the wide-range TMR sensor tunnel junction based on the artificial antiferromagnetic free layer described above in this embodiment. This sensor can be a magnetic sensor or other sensors based on a magnetic sensor, such as a current sensor, etc.

[0040] Example Two: This example is basically the same as Example One, and the main difference is as follows: As Figure 4 shown, in this example, the artificial synthetic antiferromagnetic structure in the artificial antiferromagnetic free layer 43 includes a first non-magnetic material layer 432, a first ferromagnetic material layer 433, a second non-magnetic material layer 434, and a second ferromagnetic material layer 435 that are stacked in sequence from bottom to top. The first non-magnetic material layer 432 is stacked on the upper side of the free ferromagnetic layer 431, so that an antiferromagnetic coupling is formed between the first ferromagnetic material layer 433 and the second ferromagnetic material layer 435 and the free ferromagnetic layer 431, and the magnetic moment direction of the free ferromagnetic layer 431 is pinned. In the artificial antiferromagnetic free layer 43 of this example, the second non-magnetic material layer 434 and the second ferromagnetic material layer 435 are repeatedly stacked on the first ferromagnetic material layer 433 to enhance the antiferromagnetic coupling effect, increase the interlayer exchange coupling energy in the free energy of the artificial antiferromagnetic free layer, achieve a stronger pinning effect on the free ferromagnetic layer, and expand the measurement range of the TMR sensor tunnel junction.

[0041] As an alternative implementation, the repeatedly stacked ferromagnetic material layer and non-magnetic material layer are CoFeB material layer and Ru material layer. For example, as an alternative implementation, as Figure 4 shown, in this example, the second non-magnetic material layer 434 is made of Ru material with a thickness of 0.5 nm; the second ferromagnetic material layer 435 is made of Co 20 Fe 60 B 20 material, and its thickness X is usually in the range of 1 - 2 nm.

[0042] In addition, this example also provides a sensor, including a sensor body and a TMR sensor tunnel junction disposed in the sensor body. The TMR sensor tunnel junction is the wide-range TMR sensor tunnel junction based on the artificial antiferromagnetic free layer described above in this example. This sensor can be a magnetic sensor or other sensors based on magnetic sensors, such as current sensors, etc.

[0043] Example Three: This example is basically the same as Example One, and the main difference is as follows: As Figure 5 shown, a second antiferromagnetic layer 6 is clamped between the sandwich structure 4 and the capping layer 5. In this example, by adding the second antiferromagnetic layer 6 above the artificial antiferromagnetic free layer 43, an exchange coupling can be formed with the artificial antiferromagnetic free layer 43 to achieve exchange bias, further enhance the pinning effect on the magnetic moment of the artificial antiferromagnetic free layer 43, and further expand the measurement range of the TMR sensor tunnel junction.

[0044] The second antiferromagnetic layer 6 can use IrMn material or PtMn material, such as Figure 6As shown, in this embodiment, the antiferromagnetic layer 6 uses an IrMn material. The second antiferromagnetic layer 6 in this embodiment is made of an IrMn material. As an alternative embodiment, as Figure 6 shown, the composition of the IrMn material in this embodiment is Ir 80 Mn 20 , that is, the mass percentage of the Ir element in the material is 80%, the mass percentage of the Mn element is 20%, and the thickness is 12 nm.

[0045] In addition, this embodiment also provides a sensor, including a sensor body and a TMR sensor tunnel junction disposed in the sensor body. The TMR sensor tunnel junction is the wide-range TMR sensor tunnel junction based on the artificial antiferromagnetic free layer in the foregoing of this embodiment. This sensor can be a magnetic sensor or other sensors based on a magnetic sensor, such as a current sensor, etc.

[0046] The above are only the preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A tunnel junction of a wide-range TMR sensor based on an artificial antiferromagnetic free layer, characterized in that It includes a substrate (1), a seed layer (2), a first antiferromagnetic layer (3), a sandwich structure (4), and a capping layer (5) that are sequentially stacked on the substrate (1). The sandwich structure (4) includes an artificial antiferromagnetic free layer (43), an insulating barrier layer (42), and a pinned layer (41) that are sequentially stacked from top to bottom. The artificial antiferromagnetic free layer (43) is composed of an artificial synthetic antiferromagnetic structure and a free ferromagnetic layer (431) to pin the magnetic moment direction of its free ferromagnetic layer (431) using the artificial synthetic antiferromagnetic structure. The pinned layer (41) is composed of an artificial synthetic antiferromagnetic structure and a reference ferromagnetic layer (411) to pin the magnetic moment direction of its reference ferromagnetic layer (411) using the artificial synthetic antiferromagnetic structure. The pinned layer (41) forms an exchange coupling with the first antiferromagnetic layer (3) to achieve a stronger pinning effect. The pinning directions of the artificial antiferromagnetic free layer (43) and the pinned layer (41) are perpendicular to each other in the stacking plane, so that the reference ferromagnetic layer (411) and the free ferromagnetic layer (431) have mutually perpendicular magnetic anisotropies. The pinning effect in the artificial antiferromagnetic free layer (43) is weaker than that in the pinned layer (41) so that the two have different coercive forces.

2. The tunnel junction of the wide-range TMR sensor based on the artificial antiferromagnetic free layer according to claim 1, wherein The artificial synthetic antiferromagnetic structure in the artificial antiferromagnetic free layer (43) includes a first non-magnetic material layer (432) and a first ferromagnetic material layer (433) that are sequentially stacked from bottom to top, and the first non-magnetic material layer (432) is stacked on the upper side of the free ferromagnetic layer (431) so that an antiferromagnetic coupling is formed between the first ferromagnetic material layer (433) and the free ferromagnetic layer (431) to pin the magnetic moment direction of the free ferromagnetic layer (431).

3. The tunnel junction of the wide-range TMR sensor based on an artificial antiferromagnetic free layer according to claim 1, wherein The thickness of the first non-magnetic material layer (432) is used to adjust the strength of the antiferromagnetic coupling formed between the first ferromagnetic material layer (433) and the free ferromagnetic layer (431) and to inhibit atomic diffusion. The calculation function expression of the free energy of the artificial antiferromagnetic free layer (43) is: ， In the above formula, is the free energy of the artificial antiferromagnetic free layer (43), is the anisotropy constant, is the thickness of the first ferromagnetic material layer (433), is the angle between the magnetization direction of the free ferromagnetic layer (431) and the magnetization direction of the reference ferromagnetic layer (411), and this angle is the angle between the magnetization direction of the free ferromagnetic layer (431) and the magnetization direction of the reference ferromagnetic layer (411), is the thickness of the artificial antiferromagnetic free layer (43), is the external magnetic field, is the magnetization of the free ferromagnetic layer (431), is the interlayer exchange coupling constant between the free ferromagnetic layer (431) and the first ferromagnetic material layer (433).

4. The tunneling junction of the wide-range TMR sensor based on an artificial antiferromagnetic free layer according to claim 3, characterized in that, The calculation function expression of the included angle is: ， In the above formula, is the equivalent anisotropy field, is the interlayer exchange coupling field.

5. The tunneling junction of the wide-range TMR sensor based on an artificial antiferromagnetic free layer according to claim 1, wherein The artificial synthetic antiferromagnetic structure in the artificial antiferromagnetic free layer (43) includes a first non-magnetic material layer (432), a first ferromagnetic material layer (433), a second non-magnetic material layer (434), and a second ferromagnetic material layer (435) that are sequentially stacked from bottom to top, and the first non-magnetic material layer (432) is stacked on the upper side of the free ferromagnetic layer (431) so that antiferromagnetic couplings are formed between both the first ferromagnetic material layer (433) and the second ferromagnetic material layer (435) and the free ferromagnetic layer (431) to pin the magnetic moment direction of the free ferromagnetic layer (431).

6. The tunnel junction of the wide-range TMR sensor based on the artificial antiferromagnetic free layer according to claim 2, wherein The artificial synthetic antiferromagnetic structure in the pinned layer (41) is composed of a third non-magnetic material layer (412) and a third ferromagnetic material layer (413) that are sequentially stacked from top to bottom, and the third non-magnetic material layer (412) is stacked on the lower side of the reference ferromagnetic layer (411).

7. The tunnel junction of the wide-range TMR sensor based on an artificial antiferromagnetic free layer according to claim 1, wherein A second antiferromagnetic layer (6) is disposed in a sandwich structure between the sandwich structure (4) and the capping layer (5).

8. The tunnel junction of the wide-range TMR sensor based on an artificial antiferromagnetic free layer according to claim 2, wherein The calculation function expression of the tunnel junction resistance of the wide-range TMR sensor tunnel junction is: ， In the above formula, is the tunneling resistance of the tunneling junction of the wide-range TMR sensor, and are respectively the parallel-state resistance and the anti-parallel-state resistance of the tunneling junction of the wide-range TMR sensor, is the external magnetic field, is the equivalent anisotropy field, is the interlayer exchange coupling field, is the anisotropy constant, is the magnetization of the free ferromagnetic layer (431), is the interlayer exchange coupling constant between the free ferromagnetic layer (431) and the first ferromagnetic material layer (433).

9. The tunnel junction of the wide-range TMR sensor based on an artificial antiferromagnetic free layer according to claim 6, characterized in that, The free ferromagnetic layer (431) is made of Co 20 Fe 60 B 20 material, the first non-magnetic material layer (432) is made of Ru material, the first ferromagnetic material layer (433) is made of Co 20 Fe 60 B 20 material, the reference ferromagnetic layer (411) is made of Co 40 Fe 40 B 20 material, the third non-magnetic material layer (412) is made of Ru material, the third ferromagnetic material layer (413) is made of Co 70 Fe 30 material, where the subscripts of the respective elements in the material represent the mass percentages of the corresponding elements.

10. A sensor, comprising a sensor body and a TMR sensor tunnel junction disposed in the sensor body, characterized in that, The TMR sensor tunnel junction is the wide-range TMR sensor tunnel junction based on an artificial antiferromagnetic free layer according to any one of claims 1 to 9.

Images