A self-biased D36 mode magnetoelectric sensor and its manufacturing method

Abstract

A self-biased D36 mode magnetoelectric sensor and its manufacturing method include a piezoelectric material, a magnetostrictive material, and a base. The base is provided with a groove, and a plurality of piezoelectric materials are disposed within the groove, with adjacent piezoelectric materials arranged in parallel. The polarization direction of the piezoelectric materials is perpendicular to the length of the base, and the polarization directions of adjacent piezoelectric materials are opposite. The magnetostrictive material is disposed on the top surface of the piezoelectric material and parallel to the length of the base, with the magnetostrictive material and the base sandwiching the piezoelectric material. The self-biased D36 mode magnetoelectric sensor proposed in the present invention can be used without providing a DC bias magnetic field, significantly reducing the device's energy consumption and expanding its range of use. It exhibits a high magnetoelectric coupling coefficient and is capable of detecting weak AC magnetic fields. Self-biased magnetoelectric sensors demonstrate significant advantages in weak magnetic field detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to a self-biased D36 mode magnetoelectric sensor and a manufacturing method thereof. Background Art

[0002] Magnetic sensors can measure key physical quantities such as magnetic fields and currents, and are widely used in various fields. Magnetic sensors have developed into a branch of the modern sensor industry, with widespread application in industry, defense, science and technology, and medicine. There are a wide variety of magnetic sensors, including magnetoelectric sensors, fluxgate sensors, Hall sensors, magnetoresistive sensors, magnetic resonance magnetometers, and superconducting quantum interference devices (SQUIDs). While magnetoresistive sensors offer low power consumption and size, they suffer from low resolution and difficulty improving sensitivity at low frequencies, with a detection limit of around 1 nT. Fluxgate sensors offer superior sensitivity and resolution to magnetoresistive sensors, but they place higher demands on core performance and coil winding. Improving their low-frequency sensitivity is also a significant technical challenge. Optically pumped magnetic sensors offer higher resolution, but are bulky, complex, and expensive. SQUIDs offer the highest resolution currently available, reaching femtoliters, but they also suffer from large size and high cost, and must operate in ultra-cold liquid helium environments.

[0003] Traditional magnetoelectric sensors are primarily composed of magnetostrictive materials and piezoelectric / ferroelectric materials. These materials interact through the "magneto-mechanical-electric" coupling theory, achieving the mutual conversion of electric polarization intensity to magnetization intensity. This type of magnetoelectric sensor has the following drawbacks: First, a DC bias magnetic field is required, which prevents it from being a passive device and hinders its widespread application. Second, the required DC bias magnetic field is often very high. For example, the DC bias magnetic field of Terfenol-D magnetostrictive material can reach thousands of Oe, and the DC bias magnetic field of Metglas magnetostrictive material can reach several Oe. When these materials are used, they require the use of Helmholtz coils or permanent magnets to provide the bias magnetic field, which greatly increases the device's energy consumption, system heat generation, and environmental interference. Summary of the Invention

[0004] The object of the present invention is to provide a self-biased D36 mode magnetoelectric sensor and a manufacturing method thereof to solve the above-mentioned problems.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A self-biased D36 mode magnetoelectric sensor comprises a piezoelectric material, a magnetostrictive material and a base. The base is provided with a groove, and a plurality of piezoelectric materials are arranged in the groove, with adjacent piezoelectric materials placed in parallel. The polarization direction of the piezoelectric materials is perpendicular to the length direction of the base, and the polarization directions of adjacent piezoelectric materials are opposite. The magnetostrictive material is arranged on the top surface of the piezoelectric material and is parallel to the length direction of the base. The magnetostrictive material and the base sandwich the piezoelectric material.

[0007] Optionally, the piezoelectric material includes an upper electrode surface and a lower electrode surface; the upper electrode surface and the lower electrode surface are externally connected to wires.

[0008] Optionally, the piezoelectric material and the base, and the piezoelectric material and the magnetostrictive material are connected by an adhesive.

[0009] Optionally, the piezoelectric material has a cubic structure, and the number of the piezoelectric materials is two.

[0010] Optionally, the piezoelectric material is a single crystal or polycrystalline ceramic material, specifically one of AlN, quartz, LiNbO3, BaTiO3, ZnO, Pb(Zr, Ti)O3, Pb(Mg, Nb)O3-PbTiO3, Pb(Zn, Nb)O3-PbTiO3 or BiScO3-PbTiO3.

[0011] Optionally, the magnetostrictive material is an alloy or oxide having magnetostrictive effect or a magnetostrictive composite material formed by combining them with a polymer, which is in the form of a long multilayer sheet; the alloy or oxide having magnetostrictive effect includes Metglas, terbium dysprosium iron alloy [Terfenol-D (Tb 0.27-0.30 Dy 0.73-0.70 Fe 1.90-1.95 )], nickel iron oxide (NiFe2O4), cobalt iron oxide (CoFe2O4), nickel manganese gallium alloy (Ni2MnGa), etc., or a magnetostrictive composite material formed by combining the above magnetostrictive materials with a polymer, the magnetostrictive material is a single-layer structure or a multi-layer structure.

[0012] Optionally, the base is made of one of acrylic, brass, high manganese steel, high manganese alloy, ultra-high manganese alloy, chromium alloy cast iron or chromium carbide.

[0013] In a second aspect, the present invention provides a method for manufacturing a self-biased D36 mode magnetoelectric sensor, comprising the following steps:

[0014] Step 1: Provide two piezoelectric materials, process the piezoelectric materials into the required size and shape, and clean them with ultrapure water ultrasonically;

[0015] Step 2: Electrodes are plated on the upper and lower ends of the piezoelectric material surface by annealing, evaporation or magnetron sputtering;

[0016] Step 3: After the electrodes are formed, the piezoelectric material is polarized along the thickness direction;

[0017] Step 4: Wires are respectively attached to the two electrode end surfaces of the two piezoelectric materials to conduct electrical signals;

[0018] Step 5, providing a magnetostrictive material, processing the magnetostrictive material into a desired size and shape, and cleaning it with alcohol;

[0019] Step 6: Use adhesive to bond the two piezoelectric materials with the wires attached to the base. The thickness direction of the piezoelectric material is perpendicular to the length direction of the base, and the polarization directions of the two piezoelectric materials are opposite.

[0020] Step 7: Using an adhesive, bond a piece of magnetostrictive material to the sides of the two piezoelectric materials to form a magnetoelectric composite material.

[0021] Step 8: Short-circuit the two wires on one side of the magnetoelectric composite material, lead out the signal through the wire on the other side, and connect the two piezoelectric materials in series to produce a d36 mode self-biased sensor.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] The self-biased d36 mode magnetoelectric sensor proposed in the present invention can be used without providing a DC bias magnetic field, which greatly reduces the energy consumption of the device and expands the scope of use of the device. In the proposed sensor, the polarization direction of the piezoelectric material is not perpendicular to the direction of the electric field, so the depolarization phenomenon of the piezoelectric material can be effectively suppressed. In addition, the electrode surface of the piezoelectric material in the sensor is not the same as the bonding surface connected to other components, so it is convenient to draw out the electrical signal, while avoiding the wear of the electrode surface, and the service life of the device is extended. The magnetoelectric sensor proposed in the present invention exhibits a high magnetoelectric coupling coefficient and can detect AC magnetic fields with weak signals. Self-biased magnetoelectric sensors show great advantages in weak magnetic field detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention.

[0025] Wherein: 1. piezoelectric material; 2. magnetostrictive material; 3. base; 4. upper electrode surface of piezoelectric material; 5. lower electrode surface of piezoelectric material.

[0026] Figure 2 Schematic diagram of the working mode of the self-biased magnetoelectric sensor of the present invention.

[0027] Figure 3 This is a frequency response test diagram of the self-biased d36 mode magnetoelectric sensor of the present invention under different bias magnetic fields.

[0028] Figure 4 Graph showing the test results of the AC magnetic field sensitivity of the self-biased magnetoelectric sensor of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described below with reference to the accompanying drawings:

[0030] See also Figure 1 A self-biased D36 mode magnetoelectric sensor includes a piezoelectric material 1, a magnetostrictive material 2, and a base 3; four wires are respectively connected to the upper and lower surface electrodes of the two piezoelectric materials 1; an adhesive is used to bond the side surfaces of the two piezoelectric materials 1 into the groove of the base 3 so that the two piezoelectric materials 1 are placed in parallel, with the polarization direction perpendicular to the length direction of the base 3 and the polarization directions of the two piezoelectric materials 1 opposite to each other; an adhesive is used to bond the magnetostrictive material 2 to the side surfaces of the two piezoelectric materials 1, parallel to the length direction of the base 3, and the piezoelectric material 1 is clamped in the middle; the piezoelectric material 1 includes an upper electrode surface 4 and a lower electrode surface 5, and the piezoelectric material 1 has a cubic structure.

[0031] The piezoelectric material 1 is a single crystal or polycrystalline ceramic material, specifically one of AlN, quartz, LiNbO3, BaTiO3, ZnO, Pb(Zr, Ti)O3, Pb(Mg, Nb)O3-PbTiO3, Pb(Zn, Nb)O3-PbTiO3 or BiScO3-PbTiO3.

[0032] The magnetostrictive material 2 is an alloy or oxide with magnetostrictive effect or a magnetostrictive composite material formed by combining them with a polymer, and is in the form of a long multilayer sheet. The alloy or oxide with magnetostrictive effect includes Metglas, terbium dysprosium iron alloy [Terfenol-D (Tb 0.27-0.30 Dy 0.73-0.70 Fe 1.90-1.95 )], nickel iron oxide (NiFe2O4), cobalt iron oxide (CoFe2O4), nickel manganese gallium alloy (Ni2MnGa), etc., or a magnetostrictive composite material formed by combining the above magnetostrictive materials with a polymer. The magnetostrictive material can be a single-layer structure or a multi-layer structure.

[0033] The base 3 is made of a high-hardness material, specifically one of acrylic, brass, high-manganese steel, high-manganese alloy, ultra-high-manganese alloy, chromium alloy cast iron, chromium carbide composite material, and the like.

[0034] The sides of the two piezoelectric materials are tightly bonded to a high-hardness base. When the magnetic field sensor is operating, the magnetostrictive material expands and contracts along its length under the influence of the magnetic field, and the piezoelectric material generates surface shear strain driven by the deformation of the magnetostrictive material. Because the two piezoelectric materials have opposite polarization directions, the output voltages on the same side of the two piezoelectric materials are positive and negative, respectively. By short-circuiting the wires on one side, the two piezoelectric materials can be connected in series to obtain a high output signal.

[0035] A method for manufacturing a self-biased D36 mode magnetoelectric sensor comprises the following steps:

[0036] Step 1: Provide two piezoelectric materials, process the piezoelectric materials into the required size and shape, and clean them with ultrapure water ultrasonically;

[0037] Step 2: Electrodes are plated on the upper and lower ends of the piezoelectric material surface by annealing, evaporation or magnetron sputtering;

[0038] Step 3: After the electrodes are formed, the piezoelectric material is polarized along the thickness direction;

[0039] Step 4: Four wires are respectively attached to the two electrode end surfaces of the two piezoelectric materials to conduct electrical signals;

[0040] Step 5, providing a magnetostrictive material, processing the magnetostrictive material into a desired size and shape, and cleaning it with alcohol;

[0041] Step 6: Use adhesive to bond the two piezoelectric materials with the wires attached to the base. The thickness direction of the piezoelectric material is perpendicular to the length direction of the base, and the polarization directions of the two piezoelectric materials are opposite.

[0042] Step 7: Using an adhesive, bond a piece of magnetostrictive material to the sides of the two piezoelectric materials to form a magnetoelectric composite material.

[0043] Step 8: Short-circuit the two wires on one side of the magnetoelectric composite material, and lead out the signal through the wire on the other side, so that the two piezoelectric materials are connected in series to produce a self-biased sensor in d36 mode;

[0044] Figure 2 This is a schematic diagram of the working mode of the self-biased D36 mode magnetoelectric sensor of the present invention: Since the polarization directions of the two piezoelectric materials are opposite when placed, when the magnetostrictive material expands or contracts, the in-plane shear directions of the piezoelectric materials are opposite. Under the AC magnetic field, they move back and forth, and the voltage output signals on the same side are opposite, so a larger output is obtained by series connection.

[0045] Figure 3The frequency response and DC magnetic field response test diagram of the self-biased d36 mode magnetoelectric sensor of the present invention are shown. The sensor of the present invention is self-biased and does not require external DC magnetic field bias. Under different DC magnetic field biases from -40Oe to +40Oe, the resonant frequency of the sensor of the present invention remains stable. Under zero DC magnetic field bias, the magnetoelectric coefficient at resonance is 48.8V / cm / Oe, which is significantly higher than those working in d 15 Magnetoelectric sensor in thickness shear mode.

[0046] Figure 4 Figures 1 and 2 show the AC magnetic field sensitivity test results of the self-biased magnetoelectric sensor of the present invention. (a) AC magnetic field sensitivity test results at 1 kHz operating frequency, with a detection limit of 1.7 nT. (b) AC magnetic field sensitivity test results at resonant operating frequency, with a detection limit of 10.6 pT.

[0047] The above embodiments of the present invention are merely examples for illustrating the present invention and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations and modifications can be made based on the above description. It is not possible to enumerate all embodiments here. Any obvious variations or modifications arising from the technical solution of the present invention remain within the scope of protection of the present invention.

Claims

1. A self-biased d36 mode magnetoelectric sensor, characterized in that: The invention comprises a piezoelectric material (1), a magnetostrictive material (2) and a base (3); a groove is provided on the base (3), a plurality of piezoelectric materials (1) are provided in the groove, and adjacent piezoelectric materials (1) are placed in parallel; the polarization direction of the piezoelectric material (1) is perpendicular to the length direction of the base (3), and the polarization direction of adjacent piezoelectric materials (1) is opposite; the magnetostrictive material (2) is provided on the top surface of the piezoelectric material (1) and is parallel to the length direction of the base (3), and the magnetostrictive material (2) and the base (3) clamp the piezoelectric material (1) in the middle.

2. A self-biased d36 mode magnetoelectric sensor according to claim 1, characterized in that: The piezoelectric material (1) comprises an upper electrode surface (4) and a lower electrode surface (5); the upper electrode surface (4) and the lower electrode surface (5) are externally connected to wires.

3. A self-biased d36 mode magnetoelectric sensor according to claim 1, characterized in that: The piezoelectric material (1) and the base (3), as well as the piezoelectric material (1) and the magnetostrictive material (2) are connected by an adhesive.

4. A self-biased d36 mode magnetoelectric sensor according to claim 1, characterized in that: The piezoelectric material (1) has a cubic structure, and the number of the piezoelectric materials (1) is two.

5. The self-biased d36 mode magnetoelectric sensor according to claim 1, wherein: The piezoelectric material (1) is a single crystal or polycrystalline ceramic material, specifically one of AlN, quartz, LiNbO3, BaTiO3, ZnO, Pb(Zr, Ti) O3, Pb(Mg, Nb) O3-PbTiO3, Pb(Zn, Nb) O3-PbTiO3 or BiScO3-PbTiO3.

6. A self-biased d36 mode magnetoelectric sensor according to claim 1, characterized in that: The magnetostrictive material (2) is an alloy or oxide having a magnetostrictive effect or a magnetostrictive composite material formed by combining the alloy or oxide with a polymer, and is in the form of a long multilayer sheet; the alloy or oxide having a magnetostrictive effect includes Metglas, terbium dysprosium iron alloy, nickel iron oxide, cobalt iron oxide, nickel manganese gallium alloy, or a magnetostrictive composite material formed by combining the above magnetostrictive materials with a polymer, and the magnetostrictive material is a single-layer structure or a multilayer structure.

7. A self-biased d36 mode magnetoelectric sensor according to claim 1, characterized in that: The base (3) is made of one of acrylic, brass, high manganese steel or chromium carbide.

8. A method for manufacturing a self-biased d36 mode magnetoelectric sensor, characterized in that: A self-biased d36 mode magnetoelectric sensor according to any one of claims 1 to 7, comprising the following steps: Step 1: Provide two piezoelectric materials, process the piezoelectric materials into the required size and shape, and clean them with ultrapure water ultrasonically; Step 2: Electrodes are plated on the upper and lower ends of the piezoelectric material surface by annealing, evaporation or magnetron sputtering; Step 3: After the electrodes are formed, the piezoelectric material is polarized along the thickness direction; Step 4: Wires are respectively attached to the two electrode end surfaces of the two piezoelectric materials to conduct electrical signals; Step 5, providing a magnetostrictive material, processing the magnetostrictive material into a desired size and shape, and cleaning it with alcohol; Step 6: Use adhesive to bond the two piezoelectric materials with the wires attached to the base. The thickness direction of the piezoelectric material is perpendicular to the length direction of the base, and the polarization directions of the two piezoelectric materials are opposite. Step 7: Using an adhesive, bond a piece of magnetostrictive material to the sides of the two piezoelectric materials to form a magnetoelectric composite material. Step 8: Short-circuit the two wires on one side of the magnetoelectric composite material, lead out the signal through the wire on the other side, and connect the two piezoelectric materials in series to produce a d36 mode self-biased sensor.

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