A flexible thin film structure with perpendicular exchange bias effect and a preparation method and application thereof

Abstract

The application discloses a flexible thin film structure with a vertical exchange bias effect and a preparation method and application thereof, and belongs to the technical field of spin electronics and flexible integration. The flexible thin film structure with the vertical exchange bias effect comprises, from bottom to top, a polyimide flexible substrate, a wedge-shaped buffer layer, a wedge-shaped seed layer, a ferromagnetic layer, an anti-ferromagnetic layer and a protective layer; wherein the polyimide flexible substrate, the ferromagnetic layer, the anti-ferromagnetic layer and the protective layer are all flat structure layers. The thickness of the polyimide flexible substrate is set to 10-15 microns by simultaneously adopting the wedge-shaped buffer layer and the wedge-shaped seed layer between the polyimide flexible substrate and the magnetic layer, the film stress performance is improved by adopting the above structure, the CMOS (Complementary Metal-Oxide-Semiconductor) processing technology of a device can be completely compatible, the miniaturization and batch production of the flexible device can be realized, and the complexity of the preparation technology of the flexible electronic device in a wearable device is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of spin electronics and flexible integration, and particularly relates to a flexible film structure with a perpendicular exchange bias effect and a preparation method and application thereof. BACKGROUND

[0002] Flexible electronic components are widely used in flexible display, flexible sensor and intelligent wearable device due to their unique tunability, compatibility and light weight. The prerequisite for realizing the flexibility of magnetic film devices is to master the preparation technology of flexible magnetic film. Unlike the preparation of magnetic film on a rigid substrate, the growth of magnetic film on a flexible substrate not only needs to consider the interface state between the two, but also needs to fully understand the stress state of the film, mainly because the stress / strain of the flexible substrate will cause changes in the magnetic anisotropy, micro-domain, magnetic order state and electrical transport of the magnetic film, thereby affecting the performance of the device. In order to obtain a stable flexible magnetic memory and magnetic sensor, it is necessary to avoid the influence of stress / strain on the device, and by optimizing the device preparation process and improving the device structure design, the device can maintain stable performance during deformation.

[0003] Exchange bias is derived from the interface exchange coupling effect of ferromagnetic / antiferromagnetic double-layer film system, which specifically means that the magnetic hysteresis loop of the ferromagnetic layer deviates from the zero point of the magnetic field axis, and the deviation is called exchange bias field, accompanied by an increase in coercivity. Exchange bias effect has good application prospects in magnetic recording read head, magnetic sensor and magnetic random access memory.

[0004] Exchange bias plays an important role in the field of spin electronics. Preparing a flexible film with perpendicular exchange bias and studying the influence of stress / strain on its magnetism will ultimately obtain a flexible film with stable magnetic anisotropy under stress / strain, which will have very important scientific significance and application value for the development of flexible magnetic electronic devices. SUMMARY

[0005] In order to improve the stress / strain of the flexible film with perpendicular exchange bias, the application provides a flexible film structure with a perpendicular exchange bias effect and a preparation method and application thereof. The film structure with perpendicular exchange bias is prepared on a self-prepared polyimide (PI) flexible film, and a wedge-shaped buffer layer and a wedge-shaped seed layer are simultaneously used between the PI flexible film and the ferromagnetic layer. This structure can improve the stress of the flexible exchange bias film.

[0006] One of the technical solutions provided by the application is:

[0007] A flexible thin film structure with perpendicular exchange bias effect, from bottom to top, comprises a polyimide flexible substrate, a wedge-shaped buffer layer, a wedge-shaped seed layer, a ferromagnetic layer, an anti-ferromagnetic layer and a protective layer; wherein the polyimide flexible substrate, the ferromagnetic layer, the anti-ferromagnetic layer and the protective layer are all flat structure layers.

[0008] Further, the thickness of the polyimide flexible substrate is 10-15 μm; and / or, the wedge-shaped buffer layer is prepared by oblique target sputtering, the angle between the target material and the substrate is 45°, and the thickness is 5 nm; and / or, the wedge-shaped seed layer is prepared by oblique target sputtering, the angle between the target material and the substrate is 45°, and the thickness is 5 nm; and / or, the ferromagnetic layer is composed of a single layer of Pt and a single layer of Co; the thickness of the single layer of Pt in the ferromagnetic layer is 2 nm, and the thickness of the single layer of Co is 0.8 nm; and / or, the thickness of the anti-ferromagnetic layer is 10 nm; and / or, the thickness of the protective layer is 5 nm.

[0009] In the preparation of the wedge-shaped buffer layer and the wedge-shaped seed layer, the present application controls the included angle between the target material and the substrate, performs oblique target sputtering, and obtains a wedge-shaped structure, wherein the thickness of the material in the direction perpendicular to the substrate direction continuously changes (non-uniformly), and the thickness changes linearly or non-linearly with the spatial position (such as the substrate surface to the top), rather than a fixed value. The thickness of 5 nm represents the maximum thickness (close to the side of the target material), rather than the uniform thickness of the entire structure.

[0010] The thickness of the polyimide flexible substrate is set to 10-15 μm, which provides good bending characteristics for the application of the flexible magnetic structure. The high-temperature-resistant polyimide flexible substrate can meet the annealing temperature of the exchange bias effect. The wedge-shaped buffer layer and the wedge-shaped seed layer are simultaneously used between the polyimide flexible substrate and the magnetic layer, so that the magnetic thin film is always close to the center layer of the thin film under bending strain, which will reduce the stress effect caused by bending and improve the stability of the flexible thin film.

[0011] The second technical solution provided by the present application is:

[0012] A preparation method of the flexible thin film structure with the perpendicular exchange bias effect comprises the following steps: preparing a polyimide flexible substrate on a silicon dioxide substrate, growing a wedge-shaped buffer layer on the polyimide flexible substrate by direct current magnetron sputtering and using an inclined target sputtering, growing a wedge-shaped seed layer on the wedge-shaped buffer layer by direct current magnetron sputtering and using an inclined target sputtering, growing a ferromagnetic layer on the wedge-shaped seed layer by direct current magnetron sputtering, growing an antiferromagnetic layer on the ferromagnetic layer by direct current magnetron sputtering, growing a protective layer on the antiferromagnetic layer by direct current magnetron sputtering, and preparing a magnetic thin film, and then performing magnetic field heat treatment on the magnetic thin film in a magnetic field, peeling off the polyimide flexible substrate from the silicon dioxide substrate, and preparing the flexible thin film structure with the perpendicular exchange bias effect.

[0013] Further, the preparation of the polyimide flexible substrate comprises the following steps: cleaning and drying the silicon dioxide substrate, dropping polyimide solution at a central position of the silicon dioxide substrate, forming a uniform polyimide film on the substrate surface by using a segmented variable speed spin coating method, curing the spin-coated polyimide film by using a stepwise heating process, naturally cooling the polyimide film to room temperature after curing is completed, and finally forming the polyimide flexible substrate on the silicon dioxide substrate.

[0014] Further, when the wedge-shaped buffer layer is grown, tantalum is used as the target material, the sputtering gas pressure is controlled to be 0.2 Pa, and the sputtering power is 10 W.

[0015] Further, when the wedge-shaped seed layer is grown, platinum is used as the target material, the sputtering gas pressure is controlled to be 0.3 Pa, and the sputtering power is 20 W.

[0016] Further, when the ferromagnetic layer is grown, platinum and cobalt are used as the target materials, the ferromagnetic layer is grown by cross growth, the number of cycles is 3, the sputtering gas pressure of Pt is 0.3 Pa, the sputtering power of Pt is 20 W, the sputtering gas pressure of Co is 0.3 Pa, and the sputtering power of Co is 10 W.

[0017] Further, when the antiferromagnetic layer is grown, iridium manganese is used as the target material, the sputtering gas pressure is 0.3 Pa, and the sputtering power is 20 W.

[0018] Further, when the protective layer is grown, tantalum is used as the target material, the sputtering gas pressure is 0.2 Pa, and the sputtering power is 10 W.

[0019] Further, the temperature of the heat treatment is 200℃, the time is 30 min, and a constant external magnetic field with a size of 4000 Oe perpendicular to the film surface direction is applied during the entire heat treatment process.

[0020] The third technical solution provided by the application is as follows:

[0021] The flexible thin film structure with the perpendicular exchange bias effect is used in the preparation of a flexible electronic component.

[0022] Compared with the prior art, the present application has the following advantages and technical effects:

[0023] The present application sets the thickness of the polyimide flexible substrate to 10-15 μm, and improves the stress stability of the thin film by using the wedge-shaped buffer layer and the wedge-shaped seed layer between the polyimide flexible substrate and the magnetic layer, which is fully compatible with the CMOS (Complementary Metal-Oxide-Semiconductor) processing technology of the device, can realize the miniaturization and batch production of the flexible device, and significantly reduces the complexity of the preparation process of the flexible electronic device in the wearable device. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] Figure 1 A cross-sectional structure schematic diagram of the flexible thin film structure with the perpendicular exchange bias effect prepared for Example 1 is shown in the figure.

[0026] Figure 2 A cross-sectional structure schematic diagram of the flexible thin film structure prepared for Comparative Example 1 is shown in the figure.

[0027] Figure 3 A cross-sectional structure schematic diagram of the flexible thin film structure prepared for Comparative Example 2 is shown in the figure.

[0028] Figure 4 A cross-sectional structure schematic diagram of the flexible thin film structure prepared for Comparative Example 3 is shown in the figure.

[0029] Figure 5 A flexible thin film bending measurement schematic diagram is shown in the figure.

[0030] Figure 6 An out-of-plane normalized magnetic hysteresis loop of the flexible thin film structure with the perpendicular exchange bias effect prepared for Example 1 and Comparative Example 1 is shown in the figure.

[0031] Figure 7 An out-of-plane normalized magnetic hysteresis loop of the flexible thin film structure with the perpendicular exchange bias effect prepared for Comparative Examples 2-3 is shown in the figure. DETAILED DESCRIPTION

[0032] The following detailed description of various exemplary embodiments of the application will not be considered limiting of the application, but rather a description of certain aspects, features and embodiments of the application.

[0033] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Additionally, for a range of values of a parameter, unless otherwise stated, each intervening value of the parameter is also specifically included within the scope of the present application. The intervening values of the parameter are combined with a stated value of the parameter in range form. These are only exemplary of the various preferred embodiments and are not intended to be limiting of the application. Other embodiments will occur to those skilled in the art upon consideration of this disclosure. Additionally, other modifications and variations will also be apparent to those of ordinary skill in the art as will no doubt vary the specific examples and typical

[0034] 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. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All publications mentioned in this specification are herein incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. The citation of any reference is not construed as an admission that it is prior art with respect to the present application.

[0035] Many modifications and variations of this application can be made in the light of the above teachings without departing from the spirit and scope thereof, and it is to be understood that all such modifications and variations warrant the patentable subject matter under the patent laws. Other embodiments will occur to those skilled in the art upon consideration of the specification and will be within the scope of the application. The specification and examples are illustrative only.

[0036] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", or variations thereof, are intended to be open-ended terms that mean inclusion, but not limited to, the listed materials and methods.

[0037] Room temperature of the present application refers to 25±2℃.

[0038] Example 1 Preparation of a flexible thin film structure with perpendicular exchange bias effect

[0039] 1) The cleaned and dried silicon dioxide substrate is used as a support layer for the preparation of the flexible polyimide thin film. The silicon dioxide substrate is placed in the center of the vacuum chuck of the spin coater, and the polyimide solution is dropped onto the center of the silicon dioxide substrate. A segmented variable speed spin coating method is used to form a uniform polyimide thin film on the surface of the silicon dioxide substrate. The specific operation process is as follows: ① Rotate the spin coater chuck at an acceleration of 2π rad / s 2 , and when the speed reaches 500 rpm, continue to rotate at a constant speed for 5 s; ② Based on the speed of 500 rpm, rotate at an acceleration of 4π rad / s 2The angular acceleration increases the rotational speed of the spin coater's suction cup to 1000 rpm, maintaining a constant rotational speed for 7 seconds; ③ Based on the rotational speed of 1000 rpm, the speed is increased by 6π rad / s 2 The angular acceleration increases the rotational speed of the spin coater's suction cup to 1600 rpm, and then the uniform rotation continues for 45 seconds; ④ Based on the rotational speed of 1600 rpm, the speed is increased by 8π rad / s 2 The angular acceleration increases the rotational speed of the spin coater's suction cup to 5000 rpm, and then it rotates at a constant speed for 4 seconds; ⑤ at -6πrad / s 2 The machine is decelerated by angular acceleration until it stops; a stepped heating process is used to cure the spin-coated PI film, causing it to undergo an imidization reaction to form a high-temperature resistant film. The specific operation process is as follows: ① The first step temperature is 75℃, and the holding time is 20min; ② The second step temperature is 115℃, and the holding time is 20min; ③ The third step temperature is 165℃, and the holding time is 20min; ④ The fourth step temperature is 215℃, and the holding time is 20min; ⑤ The fifth step temperature is 265℃, and the holding time is 55min; ⑥ The sixth step temperature is 325℃, and the holding time is 120min; After natural cooling to room temperature, a high-temperature resistant polyimide flexible film substrate with a thickness of 12μm is formed on the silicon dioxide substrate;

[0040] 2) Using tantalum as the target material, DC magnetron sputtering and oblique target sputtering were adopted. The angle between the target material and the substrate was 45°. The sputtering gas pressure was controlled at 0.2 Pa and the sputtering power was 10 W. A wedge-shaped buffer layer Ta with a thickness of 5 nm was formed on the polyimide flexible film layer.

[0041] 3) Using platinum as the target material, DC magnetron sputtering and oblique target sputtering were adopted. The angle between the target material and the substrate was 45°. A wedge-shaped seed layer Pt was grown on the wedge-shaped buffer layer. The sputtering pressure was 0.3 Pa, the sputtering power was 20 W, and the thickness of the platinum layer was 5 nm.

[0042] 4) Using platinum and cobalt as targets, a ferromagnetic layer [Pt / Co]3 (i.e., a magnetic layer [Pt / Co]) was sputtered onto a wedge-shaped seed layer using DC magnetron sputtering. The number of cycles was 3. The sputtering pressure for Pt was 0.3 Pa, the sputtering power was 20 W, and the thickness of a single Pt layer was 2 nm. The sputtering pressure for Co was 0.3 Pa, the sputtering power was 10 W, and the thickness of a single Co layer was 0.8 nm.

[0043] 5) Using iridium-manganese as the target material, DC magnetron sputtering was used to sputter and grow an antiferromagnetic layer IrMn on the ferromagnetic layer. The sputtering pressure was 0.3 Pa, the sputtering power was 20 W, and the thickness was 10 nm.

[0044] 6) Using tantalum as target material, direct current magnetron sputtering is adopted to sputter and grow the protective layer Ta on the antiferromagnetic layer, the sputtering gas pressure is 0.2 Pa, the sputtering power is 10 W, the thickness is 5 nm, and the magnetic thin film is prepared;

[0045] 7) The magnetic thin film is annealed at 200°C under a magnetic field (the magnetic field strength is 4000 Oe, and the direction is perpendicular to the film surface) for 30 min; the polyimide flexible substrate is peeled off from the silicon dioxide substrate, and the flexible thin film structure with vertical exchange bias effect is prepared.

[0046] The flexible thin film structure with vertical exchange bias effect prepared in the embodiment is:

[0047] Polyimide PI (12 μm) / wedge-shaped buffer layer Ta (5 nm) / wedge-shaped seed layer Pt (5 nm) / magnetic layer [Pt (2 nm) / Co (0.8 nm)]3 / antiferromagnetic layer IrMn (10 nm) / protective layer Ta (5 nm)

[0048] Figure 1 The cross-sectional structure schematic diagram of the flexible thin film structure with vertical exchange bias effect prepared in Example 1 is shown in the figure; the flexible thin film structure simultaneously has a wedge-shaped buffer layer and a wedge-shaped seed layer.

[0049] Comparative Example 1

[0050] The same as Example 1, except that in step 2), using tantalum as target material, direct current magnetron sputtering is adopted to form a tantalum buffer layer Ta with uniform thickness on the polyimide flexible thin film layer, the sputtering gas pressure is controlled to be 0.2 Pa, the sputtering power is 10 W, and the thickness of the tantalum layer is 5 nm; in step 3), using platinum as target material, direct current magnetron sputtering is adopted to grow a seed layer Pt with uniform thickness on the buffer layer, the sputtering gas pressure is 0.3 Pa, the sputtering power is 20 W, and the thickness of the platinum layer is 5 nm.

[0051] The flexible thin film structure with vertical exchange bias effect prepared in the comparative example is:

[0052] Polyimide PI (12 μm) / buffer layer Ta (5 nm) / seed layer Pt (5 nm) / magnetic layer [Pt (2 nm) / Co (0.8 nm)]3 / antiferromagnetic layer IrMn (10 nm) / protective layer Ta (5 nm).

[0053] Figure 2 The cross-sectional structure schematic diagram of the flexible thin film structure prepared in Comparative Example 1 is shown in the figure.

[0054] Comparative Example 2

[0055] The same as example 1, except that in step 3), platinum is used as the target material, and a seed layer Pt with uniform thickness is grown on the buffer layer by direct current magnetron sputtering, the sputtering pressure is 0.3 Pa, the sputtering power is 20 W, and the thickness of the platinum layer is 5 nm.

[0056] The flexible film structure with the perpendicular exchange bias effect prepared in the comparative example is as follows:

[0057] Polyimide PI (12 μm) / wedge-shaped buffer layer Ta (5 nm) / seed layer Pt (5 nm) / magnetic layer [Pt (2 nm) / Co (0.8 nm)]3 / antiferromagnetic layer IrMn (10 nm) / protective layer Ta (5 nm).

[0058] Figure 3 The cross-sectional structure diagram of the flexible film structure prepared in comparative example 2 is shown in the figure.

[0059] Comparative example 3

[0060] The same as example 1, except that in step 2), tantalum is used as the target material, and a tantalum buffer layer Ta with uniform thickness is formed on the polyimide flexible film layer by direct current magnetron sputtering, the sputtering pressure is controlled to be 0.2 Pa, the sputtering power is 10 W, and the thickness of the tantalum layer is 5 nm.

[0061] The flexible film structure with the perpendicular exchange bias effect prepared in the comparative example is as follows:

[0062] Polyimide PI (12 μm) / buffer layer Ta (5 nm) / wedge-shaped seed layer Pt (5 nm) / magnetic layer [Pt (2 nm) / Co (0.8 nm)]3 / antiferromagnetic layer IrMn (10 nm) / protective layer Ta (5 nm)

[0063] Figure 4 The cross-sectional structure diagram of the flexible film structure prepared in comparative example 3 is shown in the figure.

[0064] Performance test experiment:

[0065] The flexible film structures with the perpendicular exchange bias effect prepared in example 1 and comparative examples 1-3 are subjected to hysteresis loop tests. Figure 5 The flexible film bending measurement diagram is shown in the figure, and the above-mentioned flexible film structure is placed on a mold with a bending curvature radius (Radius of curvature, ROC) of 0.35 mm, a strain is applied, and a magnetization test is performed.

[0066] Figure 6 The out-of-plane normalized hysteresis loop of the flexible film structure with the perpendicular exchange bias effect prepared in example 1 and comparative example 1 is shown in the figure. The exchange bias field H EB = (H L+H R ) / 2, wherein H L is the coercivity of the descending branch of the hysteresis loop, H R is the coercivity of the ascending branch of the hysteresis loop; it can be seen from Figure 6 that the exchange bias field of the flexible thin film sample is 200 Oe (Example 1), 100 Oe (Comparative Example 1). Figure 7 is the out-of-plane normalized hysteresis loop of the flexible thin film structure with a perpendicular exchange bias effect prepared in Comparative Example 2-3. It can be seen from Figure 7 that the exchange bias field of the flexible thin film sample is 100 Oe (Comparative Example 2), 100 Oe (Comparative Example 3).

[0067] Comparing the magnetic measurement results of the flexible thin film structures prepared in Example 1 and Comparative Examples 1-3 under bending conditions, it can be seen that, by simultaneously increasing the wedge-shaped buffer layer and the wedge-shaped seed layer in the flexible thin film structure, the flexible thin film structure has a good perpendicular exchange bias effect under bending conditions, and the influence of stress on the magnetic properties of the flexible thin film is weakened.

[0068] In the bending strain, the upper and lower surfaces of the flexible thin film structure are subjected to stress, and only the center layer of the thin film structure is almost not subjected to stress under bending. Therefore, the distance between the thin film structure and the center layer is reduced to improve the stability. The flexible thin film structure prepared in the present application simultaneously has a wedge-shaped buffer layer and a wedge-shaped seed layer, which is always close to the center layer of the thin film under bending strain, which will reduce the stress effect caused by bending. Therefore, the flexible thin film structure with a perpendicular exchange bias effect provided by the present application comprises a polyimide (PI) flexible substrate / wedge-shaped buffer layer / wedge-shaped seed layer / ferromagnetic layer / antiferromagnetic layer / protection layer, which is subjected to less stress under bending conditions, providing a new idea for preparing devices with stable performance.

[0069] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements within the technical range disclosed in the present application can be easily thought of by those skilled in the art, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A flexible thin film structure with a vertical exchange bias effect, characterized in that, From bottom to top, it includes a flexible polyimide substrate, a wedge-shaped buffer layer, a wedge-shaped seed layer, a ferromagnetic layer, an antiferromagnetic layer, and a protective layer; wherein, the flexible polyimide substrate, the ferromagnetic layer, the antiferromagnetic layer, and the protective layer are all planar structure layers; The thickness of the polyimide flexible substrate is 10–15 μm; The wedge-shaped buffer layer is prepared by oblique target sputtering, with an angle of 45° between the target and the substrate and a thickness of 5 nm; and / or, the wedge-shaped seed layer is prepared by oblique target sputtering, with an angle of 45° between the target and the substrate and a thickness of 5 nm; The ferromagnetic layer is composed of a single layer of Pt and a single layer of Co; the thickness of the single layer of Pt in the ferromagnetic layer is 2 nm, and the thickness of the single layer of Co is 0.8 nm. The thickness of the antiferromagnetic layer is 10 nm; The thickness of the protective layer is 5 nm.

2. A method for preparing a flexible thin film structure with vertical exchange bias effect as described in claim 1, characterized in that, The process includes the following steps: preparing a flexible polyimide substrate on a silicon dioxide substrate; growing a wedge-shaped buffer layer on the flexible polyimide substrate by DC magnetron sputtering using an oblique target sputtering method; growing a wedge-shaped seed layer on the wedge-shaped buffer layer by DC magnetron sputtering using an oblique target sputtering method; growing a ferromagnetic layer on the wedge-shaped seed layer by DC magnetron sputtering; growing an antiferromagnetic layer on the ferromagnetic layer by DC magnetron sputtering; growing a protective layer on the antiferromagnetic layer by DC magnetron sputtering, thereby preparing a magnetic thin film; subjecting the magnetic thin film to heat treatment with a magnetic field, and peeling the flexible polyimide substrate off the silicon dioxide substrate to obtain the flexible thin film structure with vertical exchange bias effect.

3. The preparation method according to claim 2, characterized in that, When growing the wedge-shaped buffer layer, tantalum was used as the target material, and the sputtering gas pressure was controlled at 0.2 Pa and the sputtering power at 10 W.

4. The preparation method according to claim 2, characterized in that, When growing the wedge-shaped seed layer, platinum was used as the target material, and the sputtering pressure was controlled at 0.3 Pa and the sputtering power at 20 W.

5. The preparation method according to claim 2, characterized in that, When growing the ferromagnetic layer, platinum and cobalt were used as targets, and the growth was carried out by cross-growth with a cycle number of 3. The sputtering pressure of Pt was 0.3 Pa and the sputtering power was 20 W; the sputtering pressure of Co was 0.3 Pa and the sputtering power was 10 W.

6. The preparation method according to claim 2, characterized in that, When growing the antiferromagnetic layer, iridium manganese was used as the target material, the sputtering pressure of IrMn was 0.3 Pa, and the sputtering power was 20 W.

7. The preparation method according to claim 2, characterized in that, When growing the protective layer, tantalum was used as the target material, the sputtering pressure was 0.2 Pa, and the sputtering power was 10 W.

8. The preparation method according to claim 2, characterized in that, The heat treatment temperature is 200℃ and the time is 30min; a constant external magnetic field with a magnitude of 4000Oe perpendicular to the film surface is applied throughout the heat treatment process.

9. Use of the flexible thin film structure with vertical exchange bias effect as described in claim 1 in the fabrication of flexible electronic components.

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