Flexible magnetoelectric sensor with columnar sandwich structure and preparation method thereof

Abstract

The application discloses a flexible magnetoelectric sensor with a columnar interlayer structure and a preparation method thereof, and belongs to the technical field of micron functional materials. The flexible magnetoelectric sensor comprises a piezoelectric layer, a ferromagnetic layer and a columnar interlayer located between the piezoelectric layer and the ferromagnetic layer; the columnar interlayer is an epoxy resin film with a first surface and a second surface, a plurality of micron-level columnar structures are arranged on the first surface, the piezoelectric layer covers the first surface of the columnar interlayer and the micron-level columnar structures, and the second surface of the columnar interlayer is adhered to the ferromagnetic layer. The application further discloses a preparation method of the columnar interlayer of the flexible magnetoelectric sensor. The magnetoelectric sensor with the micron-level columnar interlayer has a uniform and controllable columnar interlayer thickness, effectively enhances the stress conduction efficiency of the flexible magnetoelectric sensor, and greatly improves the magnetoelectric coupling effect and sensing sensitivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro functional materials, in particular to a flexible magnetoelectric sensor with a columnar sandwich structure and a preparation method thereof. BACKGROUND

[0002] The flexible magnetoelectric sensor is a new type of sensor that combines the mechanical flexibility of flexible electronic devices and the non-contact detection characteristics of magnetic sensing elements, and can adapt to bending, stretching and other deformations, has higher flexibility and adaptability. Flexible electronic devices are mainly based on the magnetoelectric effect, which converts the change of external magnetic field into electrical signal output through the composite structure of magnetic material and dielectric material. The flexible magnetoelectric sensor has great development potential in the fields of wearable electronics, Internet of Things and robots due to its variability advantage.

[0003] According to the different material systems, the flexible magnetoelectric sensor is commonly divided into lead-based flexible magnetoelectric sensor and polymer-based flexible magnetoelectric sensor. The lead-based flexible magnetoelectric sensor usually takes lead zirconate titanate (PZT) and other lead-based piezoelectric ceramics as the core material, has high piezoelectric coefficient and magnetoelectric coupling performance, and therefore shows excellent performance in magnetic field sensing. However, lead-based materials have significant environmental and health risks, and the lead content may cause environmental pollution and human poisoning, which limits its use in some application scenarios with high environmental protection requirements. The polymer-based flexible magnetoelectric sensor takes polyvinylidene fluoride (PVDF) and other piezoelectric polymers as the piezoelectric layer, and takes iron, cobalt, nickel and other magnetic particles as the filler. The polymer-based flexible magnetoelectric sensor has the advantages of non-toxicity, meeting environmental protection requirements, and good flexibility and processability.

[0004] However, there are significant differences between polyvinylidene fluoride (PVDF) and lead-based piezoelectric ceramics in crystal structure, polarization mechanism, dielectric constant and mechanical properties. Due to the disordered crystal structure of polyvinylidene fluoride (PVDF), low polarization efficiency, low dielectric constant and small piezoelectric coefficient, the performance of the polymer-based flexible magnetoelectric sensor in magnetic field sensing needs to be improved compared with the lead-based flexible magnetoelectric sensor. SUMMARY

[0005] The purpose of the present application is to overcome the problems in the prior art, and to provide a flexible magnetoelectric sensor with a columnar sandwich structure, which can significantly improve the magnetoelectric coupling effect and sensing sensitivity.

[0006] The application discloses a flexible magnetoelectric sensor with a columnar interlayer structure, which comprises a piezoelectric layer, a ferromagnetic layer and a columnar interlayer between the piezoelectric layer and the ferromagnetic layer; the columnar interlayer is an epoxy resin film with a first surface and a second surface, the first surface is provided with a plurality of arrayed micron-level columnar structures, the piezoelectric layer covers the first surface of the columnar interlayer and the micron-level columnar structures, and the second surface of the columnar interlayer is adhered to the ferromagnetic layer.

[0007] The columnar interlayer can enhance force transmission of the piezoelectric layer in d31 and d33 directions, and can optimize force transmission effect by adjusting the size and spacing of the columns.

[0008] Preferably, the micron-level columnar structures are of the same shape and size.

[0009] Preferably, the micron-level columnar structures are of the same shape and size.

[0010] Preferably, the micron-level columnar structures are of the same shape and size.

[0011] The micron-level columnar structures can simultaneously enhance output voltages in d31 and d33 directions.

[0012] Preferably, the piezoelectric layer is a composite material in which barium titanate is filled into a polyvinylidene fluoride trifluoroethylene matrix, and the ferromagnetic layer is a metallic glass.

[0013] The selection of the ferromagnetic layer and the piezoelectric layer simultaneously considers magnetoelectric performance and flexibility.

[0014] Preferably, the thickness of the columnar interlayer is 20-30 um, which does not affect the deformation of the flexible magnetoelectric sensor and does not weaken the force transmission efficiency due to excessive thickness.

[0015] The application further provides a preparation method of the columnar interlayer of the flexible magnetoelectric sensor with the columnar interlayer structure.

[0016] A 3D model of a mold for preparing the columnar interlayer is designed, and the 3D model comprises a plurality of columnar grooves matched with a plurality of micron-level columnar structures in a concave structure;

[0017] The mold is prepared by a 3D printing technology, and the mold is made of acrylic resin.

[0018] Epoxy resin glue is coated on the surface of the acrylic resin mold, the excess resin on the mold is cleaned, and then the epoxy resin film with the micron-level columnar structure, i.e., the columnar interlayer, is obtained by peeling off after standing for 6-8 hours at 25-30 DEG C.

[0019] The present invention also provides a method for preparing the above-mentioned flexible magnetoelectric sensor with columnar sandwich structure, the steps of which are as follows: the second surface of the columnar sandwich is adhered to the ferromagnetic layer, and the electrospinning solution is electrospinned using an electrospinning process, and the electrospinned material is collected on the first surface of the columnar sandwich to form a piezoelectric layer; finally, an aluminum foil electrode is deposited on the upper surface of the piezoelectric layer and encapsulated to finally obtain the flexible magnetoelectric sensor.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] The flexible magnetoelectric sensor of this invention incorporates a thin film with a micron-scale columnar structure as a columnar interlayer between the upper piezoelectric layer and the lower ferromagnetic layer. This columnar interlayer effectively enhances the stress transmission efficiency of the polymer-based flexible magnetoelectric sensor and significantly improves the magnetoelectric coupling effect and sensing sensitivity. This invention is the first to propose the application of a micron-scale columnar interlayer structure in magnetoelectric sensors, significantly optimizing the performance of polymer-based flexible magnetoelectric sensors and giving them broad application prospects in fields such as magnetic field sensing and intelligent sensing.

[0022] The materials chosen for the ferromagnetic layer, piezoelectric layer, and columnar interlayer in this invention simultaneously consider both magnetoelectric performance and flexibility. This invention enhances piezoelectric performance by filling barium titanate particles into polyvinylidene fluoride trifluoroethylene body, thereby improving the magnetoelectric coupling effect and ultimately increasing the sensitivity and overall performance of the flexible magnetic field sensor. Furthermore, it utilizes metallic glass with good mechanical strength, ductility, and corrosion resistance as the ferromagnetic layer. The selection of the piezoelectric and ferromagnetic layers allows for better integration with the epoxy resin film with its micron-scale columnar structure as the columnar interlayer to fabricate a flexible magnetoelectric sensor, simultaneously enhancing the output voltage in both the d31 and d33 directions, thus improving the magnetoelectric coupling effect and sensing sensitivity. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the flexible magnetoelectric sensor device in an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of a 3D printed mold in an embodiment of the present invention.

[0025] Figure 3 This is a side view of the 3D printed mold in an embodiment of the present invention.

[0026] Figure 4 As described in the embodiments of the present invention Figure 2 A magnified view of a portion of the 3D printed mold.

[0027] Figure 5 As described in the embodiments of the present invention Figure 3A partial enlarged view of the 3D printing mold in the middle.

[0028] Figure 6 An optical microscope morphology of the columnar interlayer of the embodiment of the present application.

[0029] Figure 7 A scanning electron microscope (SEM) morphology of the columnar interlayer of the embodiment of the present application.

[0030] Figure 8 A structural model schematic diagram of the flexible magnetoelectric sensor device of the embodiment of the present application.

[0031] Figure 9 A voltage output diagram of the flexible magnetoelectric sensor without interlayer under different magnetic field conditions.

[0032] Figure 10 A voltage output diagram of the flexible magnetoelectric sensor of the embodiment of the present application using the epoxy resin film with multiple micron-level epoxy resin columnar structures as the columnar interlayer under different magnetic field conditions. DETAILED DESCRIPTION

[0033] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

[0034] Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the common meanings thereof by those of ordinary skill in the art to which the present application belongs. The terms “first”, “second” and similar terms used herein do not denote any order, quantity or importance, but are used to distinguish different components. The terms “include” or “contain” and similar terms mean that the components or objects appearing before “include” or “contain” cover the components or objects listed after “include” or “contain” and their equivalents, and do not exclude other components or objects. The terms “connect” or “connected” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “up”, “down”, “left”, “right” and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships may also be changed accordingly.

[0035] As Figure 1 and Figure 8As shown, the flexible magnetoelectric sensor with a columnar interlayer structure provided by the embodiment comprises a piezoelectric layer 1, a ferromagnetic layer 3, and a columnar interlayer 2 between the piezoelectric layer 1 and the ferromagnetic layer 3; the columnar interlayer 2 is an epoxy resin film with a first surface and a second surface, and a plurality of micron-level columnar structures 4 are arranged on the first surface; the piezoelectric layer 1 is covered on the first surface of the columnar interlayer 2 and the micron-level columnar structures 4, and the second surface of the columnar interlayer 2 is adhered to the ferromagnetic layer 3. The piezoelectric layer 1 of the embodiment is preferably a piezoelectric polymer piezoelectric layer, and as another optional mode, the piezoelectric layer 1 can also be other piezoelectric layers that can be used in flexible magnetoelectric sensors; the columnar interlayer 2 is designed between the piezoelectric layer 1 and the ferromagnetic layer 3, which can more effectively conduct stress and strain in the magnetoelectric sensor, and the columnar interlayer 2 of the embodiment can enhance the force transmission of the piezoelectric layer 1 in the d31 and d33 directions, and can also optimize the force transmission effect by adjusting the size and spacing of the columns.

[0036] As another preferred embodiment, the shape and size of the micron-level columnar structures 4 on the columnar interlayer 2 in the embodiment are the same, the cross-sectional shape of the micron-level columnar structures 4 on the columnar interlayer 2 is square, and the side length size is 20um~80um; the height of the micron-level columnar structures 4 on the columnar interlayer 2 is 50um~150um, and the spacing between adjacent micron-level columnar structures 4 is 10um~100um. The shape and size of the micron-level columnar structures 4 described above in the embodiment can simultaneously enhance the output voltage in the d31 and d33 directions, and research shows that when the micron-level columnar structures 4 are in a conical structure, only the output voltage in the d31 direction can be enhanced.

[0037] Due to its excellent piezoelectric performance, piezoelectric nanoceramic particles are often added as nanofillers to polymer-based materials to improve the electrical output and sensitivity of polymer-based flexible magnetoelectric sensors. When these particles are added as nanofillers to the flexible ferroelectric polymer polyvinylidene fluoride trifluoroethylene, i.e. {P(VDF-TrFE)}, the ferroelectricity and piezoelectricity of the composite material can be enhanced, and the piezoelectric effect can be further enhanced by filling barium titanate (BTO) particles.

[0038] Metal glass (Metglas) is a material with a non-directional alloy structure. Due to the randomness of its atomic structure, Metglas can be magnetized with relatively low energy. In addition, Metglas also has good mechanical strength, ductility, corrosion resistance, and high magnetostriction coefficient, which makes it one of the commonly used magnetic materials in magnetoelectric sensors.

[0039] As another preferred embodiment, the piezoelectric layer 1 of the embodiment is a composite material in which barium titanate (BTO) is filled into a polyvinylidene-trifluoroethylene matrix. The unique structure of the barium titanate not only provides a large specific surface area, but also effectively promotes the polarization of the polymer matrix, significantly improves the piezoelectric performance of the composite material, and thus improves the sensitivity of the magnetoelectric sensor prepared based on the composite material. The ferromagnetic layer 3 is a metallic glass, which can be magnetized with relatively low energy and has good mechanical strength, ductility, corrosion resistance, and a relatively high magnetostriction coefficient. The selection of the ferromagnetic layer 3, the piezoelectric layer 1, and the columnar interlayer 2 of the embodiment takes into account both the magnetoelectric performance and flexibility. The ferromagnetic layer 3 selected by the present application is a material with a large magnetostriction coefficient and flexibility known at present, and the piezoelectric layer 1 is also the best choice that takes into account performance and flexibility. The ferromagnetic layer 3, the piezoelectric layer 1, and the columnar interlayer 2 of the embodiment can work together to maximize the output voltage in the d31 and d33 directions.

[0040] As another preferred embodiment, the columnar interlayer 2 of the embodiment is an epoxy resin film with micron-level columnar structures 4 integrally formed. The epoxy resin film is arrayed with a plurality of micron-level epoxy resin columnar structures.

[0041] As another preferred embodiment, the thickness of the columnar interlayer 2 in the embodiment is 20-30 um, which does not affect the deformation of the flexible magnetoelectric sensor and does not weaken the force transmission efficiency due to excessive thickness.

[0042] The embodiment also discloses a preparation method of the flexible magnetoelectric sensor with the columnar interlayer 2 structure. In the preparation, the columnar interlayer 2 is first prepared, and then the prepared columnar interlayer 2 is assembled with the piezoelectric layer 1 and the ferromagnetic layer 3 to form the flexible magnetoelectric sensor with the columnar interlayer 2 structure. The following will be described in detail in the form of specific embodiments.

[0043] Embodiment 1

[0044] The preparation method of the columnar interlayer of the flexible magnetoelectric sensor with the columnar interlayer structure of the embodiment includes the following steps:

[0045] Step 1: design a 3D model of a mold 5 for preparing the columnar interlayer 2. The structure of the 3D model is as shown in Figures 2-5 The 3D model includes a plurality of columnar grooves 6 with a size of 50 um x 50 um x 100 um, and the spacing between adjacent columnar grooves 6 is 10 um. The 3D model further includes a recessed structure 7, and the depth of the recessed structure 7 is 100 um. In the embodiment, the depth of the recessed structure 7 is greater than the thickness of the columnar interlayer 2, which facilitates peeling and controlling the thickness of the columnar interlayer 2. The mold 5 is prepared by 3D printing technology, and the material of the mold 5 is acrylic resin. In the embodiment, the thickness of the columnar interlayer 2 is the distance between the first surface and the second surface.

[0046] Step two: mix the full transparent epoxy resin AB glue evenly, and evenly coat on the surface of the mold 5, use the scraper to flatten and scrape off the excess resin, which is convenient for uniform film thickness, control the thickness of the columnar interlayer 2 to be 20um~30um; at a temperature of 25℃, stand for 7h, peel off the epoxy resin film with columnar structure, that is, the columnar interlayer 2. In this embodiment, standing at 25℃ for 7h can realize convenient demolding, avoid completely dry and cause demolding failure or difficult demolding.

[0047] The preparation method of the flexible magnetoelectric sensor with columnar interlayer structure in this embodiment is as follows:

[0048] 20wt% of barium titanate (BTO) nanoparticles are added to a solution of 1g polyvinylidene fluoride trifluoroethylene P(VDF-TrFE) and 5ml dimethylformamide (DMF), stirred for 12h to prepare a composite electrospinning solution, and electrospinning is carried out under an interelectrode voltage of 20kV, collected by a metal glass (Metglas) ferromagnetic layer 3 attached with the columnar interlayer 2, and a piezoelectric layer 1 is obtained. The flexible magnetoelectric sensor is prepared by attaching an aluminum foil on the piezoelectric layer 1.

[0049] Example 2

[0050] The preparation method of the columnar interlayer of the flexible magnetoelectric sensor with columnar interlayer structure in this embodiment includes the following steps:

[0051] Step one: design a 3D model of the mold 5 for preparing the columnar interlayer 2, which includes a plurality of columnar grooves 6 with a size of 20um×20um×100um, and the spacing between adjacent columnar grooves 6 is 100um, and a concave structure 7 is also designed inside the 3D model, the depth of the concave structure 7 is 100um, the mold 5 is prepared by 3D printing technology, and the material of the mold 5 is acrylic resin.

[0052] Step two: mix the full transparent epoxy resin AB glue evenly, and evenly coat on the surface of the mold 5, use the scraper to flatten and scrape off the excess resin, which is convenient for uniform film thickness, control the thickness of the columnar interlayer 2 to be 20um~30um, at a temperature of 30℃, stand for 6h, peel off the epoxy resin film with columnar structure, that is, the columnar interlayer 2. In this embodiment, standing at 30℃ for 6h can realize convenient demolding, avoid completely dry and cause demolding failure or difficult demolding.

[0053] The preparation method of the flexible magnetoelectric sensor with columnar interlayer structure in this embodiment is as follows:

[0054] The 20wt% BTO nanoparticles are added to the solution of 1g P(VDF-TrFE) and 5ml DMF, stirred for 12h to prepare a composite electrospinning solution, and electrospun under an inter-electrode voltage of 20kV, collected by Metglas ferromagnetic layer 3 attached to the columnar interlayer 2, and the obtained spinning composite film is the piezoelectric layer 1, and the flexible magnetoelectric sensor is prepared by attaching an aluminum foil on the piezoelectric layer 1.

[0055] Example 3

[0056] The preparation method of the columnar interlayer of the flexible magnetoelectric sensor with a columnar interlayer structure in this embodiment includes the following steps:

[0057] Step one: design a 3D model of the mold 5 for preparing the columnar interlayer 2, which includes a plurality of columnar grooves 6 with a size of 80umx80umx50um, and the spacing between adjacent columnar grooves 6 is 100um, and a concave structure 7 is also designed inside the 3D model, and the depth of the concave structure 7 is 100um, and the mold 5 is prepared by 3D printing technology, and the material of the mold 5 is acrylic resin.

[0058] Step two: mix the full-transparent epoxy resin AB glue uniformly, and uniformly coat it on the surface of the mold 5, and use a scraper to flatten and scrape off the excess resin, which is convenient for uniform film thickness and controls the thickness of the columnar interlayer 2 to be 20um-30um, and stand still at a temperature of 28℃ for 6h, and peel off the epoxy resin film with columnar structure, which is the columnar interlayer 2. In this embodiment, standing still at a temperature of 28℃ for 6h can realize convenient demolding and avoid complete dryness which will lead to demolding failure or difficulty in demolding.

[0059] The preparation method of the flexible magnetoelectric sensor with a columnar interlayer structure in this embodiment is as follows:

[0060] The 20wt% BTO nanoparticles are added to the solution of 1g P(VDF-TrFE) and 5ml DMF, stirred for 12h to prepare a composite electrospinning solution, and electrospun under an inter-electrode voltage of 20kV, collected by Metglas ferromagnetic layer 3 attached to the columnar interlayer 2, and the obtained spinning composite film is the piezoelectric layer 1, and the flexible magnetoelectric sensor is prepared by attaching an aluminum foil on the piezoelectric layer 1.

[0061] Example 4

[0062] The preparation method of the columnar interlayer of the flexible magnetoelectric sensor with a columnar interlayer structure in this embodiment includes the following steps:

[0063] Step one: design a 3D model of the mold 5 for preparing the columnar interlayer 2, the 3D model includes a plurality of columnar grooves 6 with a size of 50umx50umx150um, the spacing between adjacent columnar grooves 6 is 100 microns, and a concave structure 7 is also designed inside the 3D model, the depth of the concave structure 7 is 100um, the mold 5 is prepared by 3D printing technology, and the material of the mold 5 is acrylic resin.

[0064] Step two: mix the full transparent epoxy AB glue uniformly, and uniformly coat it on the surface of the mold 5, use a scraper to flatten and scrape off the excess resin, so as to facilitate the uniformity of the film thickness and control the thickness of the columnar interlayer 2 to be 20um-30um, and then stand still at a temperature of 25℃ for 7h, and then peel off the epoxy resin film with columnar structure, that is, the columnar interlayer 2. In this embodiment, standing still at a temperature of 25℃ for 7h can realize convenient demolding, and avoid that complete dryness will lead to demolding failure or difficulty in demolding.

[0065] The preparation method of the flexible magnetoelectric sensor with the columnar interlayer structure in this embodiment is as follows:

[0066] 20wt% of BTO nanoparticles are added into a solution of 1g of P(VDF-TrFE) and 5ml of DMF, the composite electrospinning solution is prepared by stirring for 12h, and electrospinning is carried out under an interelectrode voltage of 20kV, and the Metglas ferromagnetic layer 3 attached with the columnar interlayer 2 is used for collection, and the obtained spinning composite film is the piezoelectric layer 1, and the flexible magnetoelectric sensor is prepared by attaching an aluminum foil on the piezoelectric layer 1.

[0067] In order to test the surface morphology of the columnar interlayer 2 prepared in this embodiment, the columnar interlayer 2 prepared in Example 1 is placed on a glass slide and conductive glue respectively, and the morphology is tested by using an optical microscope and a scanning electron microscope.

[0068] As shown in Figure 6 , the optical microscope result shows that the micron-level columnar structures 4 are arranged in order and have uniform size. As shown in Figure 7 , the scanning electron microscope result shows that the thickness of the columnar interlayer 2 is controllable, and the height of the micron-level columnar structure 4 is adjustable.

[0069] In order to test the performance of the columnar interlayer 2 prepared in this embodiment, the columnar interlayer 2 is compounded with P(VDF-TrFE) and Metglas to prepare a magnetoelectric sensor and test the sensitivity in this embodiment.

[0070] This embodiment also tests the output voltage of the flexible magnetoelectric sensor prepared in Example 1 under different magnetic field conditions, and a control group is also set. The difference between the control group and the flexible magnetoelectric sensor prepared in Example 1 is only that there is no interlayer. The piezoelectric layer 1 and the ferromagnetic layer 3 of the control group are the same as those in Example 1 of the present application.

[0071] The voltage output graph of the flexible magnetoelectric sensor of this embodiment under different magnetic field conditions Figure 9 The voltage output graph of the flexible magnetoelectric sensor of this embodiment under different magnetic field conditions Figure 10 The voltage output graph of the flexible magnetoelectric sensor of this embodiment under different magnetic field conditions

[0072] As shown in Figure 10 The flexible magnetoelectric sensor can obtain the highest output voltage when the epoxy resin film with multiple micron-level epoxy resin columnar structures is added as the columnar interlayer 2 between the piezoelectric layer 1 and the ferromagnetic layer 3, compared with Figure 9 the case without interlayer, the output voltage is increased by 260%, which shows that it has high sensitivity and resolution.

[0073] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and changes can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A flexible magnetoelectric sensor having a pillar sandwich structure, characterized by, The piezoelectric layer, the ferromagnetic layer and the columnar interlayer located between the piezoelectric layer and the ferromagnetic layer; The columnar interlayer is an epoxy resin film with a first surface and a second surface, the first surface has a plurality of arrayed micron-level columnar structures, the piezoelectric layer covers the first surface and the micron-level columnar structures of the columnar interlayer, and the second surface of the columnar interlayer is adhered to the ferromagnetic layer.

2. The flexible magnetoelectric sensor having a pillar sandwich structure of claim 1, wherein, The micron-level columnar structures have the same shape and size.

3. The flexible magnetoelectric sensor having a pillar sandwich structure of claim 1, wherein, The cross-sectional shape of the micron-level columnar structures is square, and the side length is 20-80 um.

4. The flexible magnetoelectric sensor having a pillar sandwich structure of claim 3, wherein, The height of the micron-level columnar structures is 50-150 um, and the distance between adjacent micron-level columnar structures is 10-100 um.

5. The flexible magnetoelectric sensor having a pillar-in-clamp structure of claim 1, wherein, The piezoelectric layer is a composite material in which barium titanate is filled into a polyvinylidene fluoride trifluoroethylene matrix, and the ferromagnetic layer is a metallic glass.

6. The flexible magnetoelectric sensor having a pillar sandwich structure of claim 1, wherein, The thickness of the columnar interlayer is 20-30 um.

7. The method of claim 1-6, wherein the method is characterized by, The method comprises the following steps: designing a 3D model of a mold for preparing the columnar interlayer, the 3D model comprising a concave structure and a plurality of columnar grooves matching the plurality of micron-level columnar structures; preparing the mold by 3D printing technology, and the material of the mold is acrylic resin; applying epoxy resin glue to the surface of the acrylic resin mold, cleaning the excess resin on the mold, and then peeling off the epoxy resin film with micron-level columnar structures, i.e. the columnar interlayer, after standing for 6-8 h at 25-30℃.

8. The method for fabricating a flexible magnetoelectric sensor with a columnar sandwich structure as described in claim 1, characterized in that, The steps are as follows: adhering the second surface of the columnar interlayer to the ferromagnetic layer, and electrospinning the electrospinning solution by electrospinning process, and collecting the electrospun product on the first surface of the columnar interlayer to form the piezoelectric layer; Finally, depositing an aluminum foil electrode on the upper surface of the piezoelectric layer and packaging, and finally obtaining a flexible magnetoelectric sensor.

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