Double-layer abnormal Hall effect thin film material, preparation method and sensor

Abstract

The invention relates to the technical field of magnetic field detection, in particular to a double-layer abnormal Hall effect thin film material, a preparation method and a sensor. The double-layer abnormal Hall effect thin film material comprises a bottom abnormal Hall effect thin film; an intermediate insulating layer; an upper layer abnormal Hall effect thin film; and an upper protective layer. According to the double-layer abnormal Hall effect thin film material and the sensor thereof, strain regulation and control of magnetic anisotropy are achieved by introducing the insulating layer, the double-layer abnormal Hall effect thin film material and the sensor thereof have the advantages of being simple in structure, high in sensitivity and wide in measurement range, the overall measuring range can be regulated and controlled by applying voltage in the vertical direction, and the double-layer abnormal Hall effect thin film material and the sensor are suitable for various magnetic field detection application scenes. The sensor not only has a wide application prospect in the traditional industrial and electronic fields, but also has an important application potential in future intelligent and miniaturized electronic equipment. By optimizing the material and the structural design, a new thought and method are provided for the development of the high-performance magnetic field sensor.

Description

Technical Field

[0001] The invention relates to the technical field of magnetic field detection, in particular to a double-layer anomalous Hall effect thin film material, a preparation method and a sensor. Background Art

[0002] With the development of the Internet of Things and smart devices, the demand for compact and multifunctional magnetic field sensors has increased dramatically. In modern electronic devices, magnetic field sensors are widely used in position detection, speed sensing, angle measurement, electronic compass and other fields. Traditional Hall effect sensors have some limitations in practical applications, such as low sensitivity, poor temperature stability and insufficient anti-interference ability.

[0003] As a new type of magnetic field sensor, anomalous Hall effect sensors have significant advantages. First, anomalous Hall effect sensors show higher sensitivity and better linearity in high magnetic field environments. This enables them to perform high-precision magnetic field measurements under extreme conditions. Second, anomalous Hall effect sensors have stronger resistance to magnetic field shocks and can maintain stable working performance in strong magnetic field environments.

[0004] In addition, the anomalous Hall effect sensor has obvious advantages in miniaturization and integration. Due to its simple structure, it can be easily integrated with other electronic components to form a highly integrated sensing system. This makes the anomalous Hall effect sensor have a wide range of application prospects in portable devices and microelectronic systems.

[0005] In recent years, with the advancement of thin film material preparation technology, especially the development of pulsed laser deposition and magnetron sputtering, the thickness and composition of thin films can be precisely controlled, thereby achieving precise regulation of the properties of thin film materials. Using these technologies, anomalous Hall effect thin film materials with excellent properties can be prepared, further improving the performance of sensors.

[0006] However, in practical applications, anomalous Hall effect sensors still face some challenges. For example, how to achieve multi-range detection and improve anti-interference capabilities of sensors, how to maintain high-precision measurements in complex environments, etc. These problems need to be solved through material design and structural optimization. Summary of the invention

[0007] In view of the above problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the first object of the present invention is to provide a double-layer anomalous Hall effect thin film material, which can solve the problem that the abnormal Hall effect sensor cannot perform multi-range detection.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions: a double-layer anomalous Hall effect thin film material, comprising a substrate layer; a bottom anomalous Hall effect thin film with a thickness of 5nm to 20nm; an intermediate insulating layer with a thickness of about 10nm and a material of NiO, MgAl 2 O 4 Or MgO, located on the bottom anomalous Hall effect film; an upper anomalous Hall effect film, with a thickness of 5nm to 20nm, located on the middle insulating layer; an upper protective layer, with a thickness of 5nm to 10nm, located on the upper anomalous Hall effect film.

[0010] As a preferred solution of the double-layer abnormal Hall effect film material of the present invention, the bottom abnormal Hall effect film and the upper abnormal Hall effect film are both made of NiCo 2 O 4 Material.

[0011] As a preferred solution of the double-layer anomalous Hall effect thin film material of the present invention, the sensitivity and measurement range of the material can be regulated by adjusting the thickness of the upper anomalous Hall effect thin film.

[0012] The second object of the present invention is to propose a method for preparing a double-layer anomalous Hall effect thin film material, which comprises the following steps: providing a single crystal material as a substrate layer; sequentially growing a bottom anomalous Hall effect thin film, an intermediate insulating layer, an upper anomalous Hall effect thin film and an upper protective layer on the substrate layer; patterning the Hall bar structure by a photolithography process; and conducting an electrical performance test.

[0013] As a preferred solution of the method for preparing the double-layer anomalous Hall effect thin film material of the present invention, the bottom layer anomalous Hall effect thin film and the upper layer anomalous Hall effect thin film are deposited by pulsed laser deposition or magnetron sputtering.

[0014] The third object of the present invention is to provide a magnetic field sensor that can achieve multi-range detection and improve anti-interference capabilities of the sensor, and maintain high-precision measurement in complex environments.

[0015] To solve the above technical problems, the present invention provides the following technical solutions: a magnetic field sensor, comprising a double-layer anomalous Hall effect thin film material; a processing circuit connected to the double-layer anomalous Hall effect thin film material; a range comparison and output selection module connected to the processing circuit.

[0016] As a preferred solution of the magnetic field sensor of the present invention, the processing circuit includes signal amplification, filtering and digital processing modules.

[0017] As a preferred solution of the magnetic field sensor of the present invention, the magnetic field sensor further includes an anti-interference module.

[0018] As a preferred solution of the magnetic field sensor of the present invention, the voltage is applied in the vertical direction of the magnetic field sensor to adjust the range.

[0019] As a preferred solution of the magnetic field sensor of the present invention, the bottom layer and the upper layer of the double-layer anomalous Hall effect thin film material respectively detect signals of different ranges, and the output signals are integrated through a dual-channel structure.

[0020] The beneficial effects of the present invention are as follows: the double-layer anomalous Hall effect thin film material and its sensor of the present invention realize strain-controlled magnetic anisotropy by introducing an insulating layer, and have the advantages of simple structure, high sensitivity, and wide measurement range. Moreover, by applying voltage in the vertical direction, the overall range can be controlled, and it is suitable for a variety of magnetic field detection application scenarios. The sensor not only has broad application prospects in traditional industrial and electronic fields, but also has important application potential in future intelligent and miniaturized electronic devices. By optimizing materials and structural design, the present invention provides new ideas and methods for the development of high-performance magnetic field sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0022] Figure 1 Schematic diagram of the structure of a double-layer anomalous Hall effect thin film material.

[0023] Figure 2 Schematic diagram of the device structure of a double-layer anomalous Hall effect thin film sensor.

[0024] Figure 3 The Hall resistance of the two sensor channels varies with the magnetic field in the range of 10mT and 1000mT.

[0025] Figure 4 Schematic diagram of application range switching of double-layer anomalous Hall effect sensor. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive with other embodiments, either individually or selectively.

[0029] Example 1

[0030] Reference Figure 1 , which is the first embodiment of the present invention, and provides a double-layer abnormal Hall effect thin film material, the double-layer abnormal Hall effect thin film material comprises a substrate layer 100; a bottom abnormal Hall effect thin film 200, the thickness of which is 5nm to 20nm; an intermediate insulating layer 300, the thickness of which is about 10nm, and the material is NiO, MgAl 2 O 4 or MgO, located on the bottom abnormal Hall effect film 200; the upper abnormal Hall effect film 400, with a thickness of 5nm to 20nm, located on the middle insulating layer 300; the upper protective layer 500, with a thickness of 5nm to 10nm, located on the upper abnormal Hall effect film 400;

[0031] It is worth noting that the selection and thickness control of the bottom anomalous Hall effect film 200 are crucial to achieve high sensitivity and low noise magnetic field detection; the middle insulating layer 300 is used to isolate the two layers of anomalous Hall effect films and control their performance through lattice matching. This structural design helps to reduce the leakage current and noise of the sensor and improve the measurement accuracy and stability;

[0032] The thickness of the upper abnormal Hall effect film 400 is usually lower than that of the underlying film material to achieve a wider measurement range; the combination of the upper abnormal Hall effect film 400 and the underlying abnormal Hall effect film 200 enables the sensor to achieve multi-range detection under different operating modes; the upper protective layer 500 is preferably made of insulating materials such as MgO, which is mainly used to protect the upper abnormal Hall effect film to prevent it from being affected by the external environment during operation and to extend the service life of the sensor.

[0033] Specifically, the bottom abnormal Hall effect film 200 and the upper abnormal Hall effect film 400 are both made of NiCo 2 O 4 Material;

[0034] NiCo 2 O 4 It has excellent anomalous Hall effect, and by precisely controlling its thickness, the sensitivity and linearity of the sensor can be optimized.

[0035] Specifically, by adjusting the thickness of the upper anomalous Hall effect film 400 , the sensitivity and measurement range of the material can be regulated.

[0036] Example 2

[0037] Reference Figure 1-2 , which is a second embodiment of the present invention, provides a method for preparing a double-layer anomalous Hall effect thin film material, comprising the following steps:

[0038] Provide a single crystal material as the substrate layer, preferably single crystal silicon (Si), sapphire (Al2O3) or gallium arsenide (GaAs). Ultrasonic clean the substrate to remove surface impurities and ensure high quality of film growth;

[0039] A bottom abnormal Hall effect film, a middle insulating layer, an upper abnormal Hall effect film and an upper protective layer are sequentially grown on the substrate layer;

[0040] The Hall bar structure is patterned by photolithography. The grown thin film material is patterned into a Hall bar structure by standard photolithography. Fine processing techniques such as electron beam etching (E-beam Lithography) or ion etching (Ion Milling) are used to ensure the high precision and high consistency of the Hall bar structure. During the patterning process, attention should be paid to the lead-out and isolation of the bottom and top magnetic sensitive material electrodes, such as Figure 2 As shown, the bottom abnormal Hall effect film 200 and the fixed layer abnormal Hall effect film 400 are both patterned into a Hall Bar shape, and electrodes are respectively drawn out to realize abnormal Hall signal measurement;

[0041] Electrical performance tests were conducted on the patterned double-layer anomalous Hall effect thin film material to verify its sensitivity, linear range and anti-interference performance, and the relationship between the Hall resistance and the magnetic field of the film was measured using a Hall Effect Measurement System.

[0042] Specifically, the deposition of the bottom layer anomalous Hall effect film and the upper layer anomalous Hall effect film is carried out by pulsed laser deposition or magnetron sputtering;

[0043] Growth of bottom anomalous Hall effect film: Pulsed laser deposition (PLD) or magnetron sputtering is used to grow a 5nm to 20nm thick bottom anomalous Hall effect film on the substrate. The preferred material is NiCo2O4, and the deposition parameters such as temperature, gas pressure and laser energy are adjusted to ensure high crystalline quality and excellent electrical properties of the film;

[0044] Growth of the intermediate insulating layer: Deposit an intermediate insulating layer of about 10 nm thick on the bottom film. The preferred material is NiO, MgAl2O4 or MgO. The same deposition technology (PLD or Sputtering) is used, and the deposition parameters are adjusted to achieve high-quality growth of the insulating layer to ensure good lattice matching and electrical insulation performance.

[0045] Growth of the upper abnormal Hall effect film: grow an upper abnormal Hall effect film with a thickness of 5nm to 20nm on the intermediate insulating layer. The preferred material is also NiCo2O4.

[0046] By adjusting the thickness of the upper film, the sensitivity and measuring range of the sensor can be optimized.

[0047] Growth of upper protective layer: Deposit an upper protective layer with a thickness of 5 nm on the upper anomalous Hall effect film. The preferred material is an insulating material such as MgO; the upper protective layer is used to protect the anomalous Hall effect film and prevent it from being affected by the environment during operation.

[0048] It is worth noting that each layer of material has similar crystal structure and unit cell parameters, which ensures that the intermediate insulating layer can have a certain regulatory effect on the strain of the underlying material, thereby affecting its measurement range and output.

[0049] Example 3

[0050] Reference Figure 1 to Figure 4 , which is the third embodiment of the present invention, provides a magnetic field sensor based on a double-layer abnormal Hall effect thin film material, including a double-layer abnormal Hall effect thin film material; a processing circuit 600 connected to the double-layer abnormal Hall effect thin film material; a range comparison and output selection module connected to the processing circuit 600;

[0051] The processing circuit 600 is used to receive the output signal of the thin film material and calculate the magnetic field value according to a preset algorithm;

[0052] The range comparison and output selection module roughly determines the test result with the highest range output accuracy through the output range. The module can automatically select the best range and output mode according to different measurement requirements.

[0053] Ensure that the sensor can provide high-precision measurement results in various application scenarios.

[0054] Specifically, the processing circuit 600 includes a signal amplification, filtering and digital processing module, which is used to receive and process the output signal of the Hall effect thin film material.

[0055] Specifically, the magnetic field sensor also includes an anti-interference module, which is used to eliminate spatial magnetic field interference and ensure the accuracy of the measurement results. This module effectively improves the sensor's anti-interference ability in complex environments by superimposing preset interference signals and using an iterative algorithm to calculate the actual magnetic field value;

[0056] The anti-interference module includes hardware and software parts. The hardware part includes filters, shielding layers and interference signal superimposers; the software part includes signal processing algorithms and iterative calculation programs.

[0057] Specifically, the range can be adjusted by applying a voltage in a vertical direction of the magnetic field sensor.

[0058] Specifically, the bottom layer and the upper layer of the double-layer anomalous Hall effect thin film material respectively detect signals of different ranges, and the output signals are integrated through a dual-channel structure.

[0059] Example 4

[0060] This embodiment provides the steps of electrical performance testing:

[0061] Test equipment preparation: Use an electromagnetic test station, including liquid nitrogen thermostat, electromagnet, gauss meter, current source and nanovoltmeter to ensure the accuracy of the test.

[0062] Sensitivity and linear range test: At room temperature, use an electromagnetic test station to test the relationship between the sensor's Hall resistance and magnetic field to analyze its sensitivity and linear range. By adjusting the input current and observing the change in the sensor's Hall resistance under different currents, determine its optimal operating current.

[0063] Range control test: By applying voltage in the vertical direction of the sensor, the overall range of the sensor is controlled. Test the sensitivity and measurement range of the sensor under different voltages to verify the effectiveness of the range control function.

[0064] Interference environment setting: Introduce multiple interference sources into the test environment, such as electromagnetic interference (EMI) and radio frequency interference (RFI), to simulate the complex interference conditions in the actual working environment.

[0065] Anti-interference performance test: Conduct electrical performance tests on the sensor in different interference environments to analyze the relationship between its Hall resistance and magnetic field. Compare the test results with and without the anti-interference module to verify the effectiveness of the anti-interference module.

[0066] Result analysis and optimization: Based on the test results, analyze the performance of the sensor in different interference environments and optimize the design of the anti-interference module. Adjust the hardware and software parameters to improve the anti-interference ability of the sensor and ensure its stable operation in various complex environments.

[0067] Example 5

[0068] Reference Figure 3-4 This embodiment provides a sensor test performance case.

[0069] Specifically, in Example 5, a double-layer anomalous Hall effect thin film material is used to test the performance of the sensor. The specific materials are as follows:

[0070] Bottom layer anomalous Hall effect film: NiCo2O4 with a thickness of 10nm.

[0071] Intermediate insulating layer: MgAl2O4 is selected with a thickness of 10nm.

[0072] Upper anomalous Hall effect film: NiCo2O4 is selected with a thickness of 7.5nm.

[0073] Upper protective layer: MgO is selected with a thickness of 5nm.

[0074] Test Results

[0075] The relationship between Hall resistance and magnetic field:

[0076] The Hall resistance of the two sensor channels varies with the magnetic field in the range of 10mT and 1000mT. Figure 3 As shown in the figure, the top film channel (Top Layer) has a sensitivity of 10000V / (AT) within the range of ±0.1mT, while the bottom film channel (Bottom Layer) has a competitive sensitivity of 60V / (AT) within the range of ±5mT, and achieves an ultra-wide measurement range within the range of ±1000mT. That is, the compatibility of wide and narrow ranges is achieved.

[0077] Figure 4 The application scenarios under actual working conditions are demonstrated. That is, the application range switching diagram of the double-layer abnormal Hall effect sensor, in which a double-layer abnormal Hall sensor is used. By combining the outputs of the upper and lower Hall bars, multifunctional monitoring of normal transmission current, short circuit and sensor abnormality can be achieved.

[0078] Specifically:

[0079] Double-layer structure: The sensor consists of two layers of Hall bars, each capable of measuring the magnetic field independently.

[0080] Signal integration: By combining the output signals of the upper and lower Hall bars, the sensor can provide more comprehensive measurement data. This dual-layer structure enables the sensor to measure magnetic fields over a wider range and distinguish between normal transmission current, short circuits, and abnormal conditions of the sensor itself.

[0081] Multi-function monitoring: This output logic allows the sensor to measure not only normal current, but also short circuit conditions and abnormal sensor conditions. In actual measurement, the output of the high-range channel is analyzed to determine the fault, while the low-range output is used for fine detection. This means that the sensor has multiple functions and can provide more comprehensive and accurate data in applications such as power grid monitoring. Compared with magnetoresistive sensors, this sensor has a stronger ability to resist magnetic field shocks.

[0082] Through the above design and logic, the double-layer anomalous Hall effect sensor can provide high-precision and high-reliability magnetic field measurement in complex environments, while also having multi-functional monitoring capabilities. These features make it have broad prospects in practical applications.

[0083] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A double-layer anomalous Hall effect thin film material, characterized in that: include, A substrate layer (100); A bottom layer anomalous Hall effect film (200) having a thickness of 5 nm to 20 nm; An intermediate insulating layer (300) with a thickness of about 10 nm and made of NiO, MgAl2O4 or MgO, located on the bottom layer anomalous Hall effect film (200); An upper anomalous Hall effect film (400) with a thickness of 5 nm to 20 nm, located on the intermediate insulating layer (300); The upper protective layer (500) has a thickness of 5 nm to 10 nm and is located on the upper anomalous Hall effect film (400).

2. The double-layer anomalous Hall effect thin film material according to claim 1, characterized in that: The bottom layer abnormal Hall effect film (200) and the upper layer abnormal Hall effect film (400) are both made of NiCo2O4 material.

3. The double-layer anomalous Hall effect thin film material according to claim 1 or 2, characterized in that: By adjusting the thickness of the upper anomalous Hall effect film (400), the sensitivity and measurement range of the material can be regulated.

4. A method for preparing a double-layer anomalous Hall effect thin film material, characterized in that: include, providing a single crystal material as a substrate layer; Growing a bottom abnormal Hall effect film, a middle insulating layer, an upper abnormal Hall effect film and an upper protective layer in sequence on the substrate layer; Patterning the Hall bar structure by photolithography; Conduct electrical performance tests.

5. The method for preparing a double-layer anomalous Hall effect thin film material according to claim 4, characterized in that: The bottom layer anomalous Hall effect film and the upper layer anomalous Hall effect film are deposited by pulse laser deposition or magnetron sputtering.

6. A magnetic field sensor based on the double-layer anomalous Hall effect thin film material according to any one of claims 1 to 3, characterized in that: include, Double-layer anomalous Hall effect thin film material; A processing circuit (600) connected to the double-layer anomalous Hall effect thin film material; A range comparison and output selection module is connected to the processing circuit (600).

7. The magnetic field sensor according to claim 6, characterized in that: The processing circuit (600) includes signal amplification, filtering and digital processing modules.

8. The magnetic field sensor according to claim 7, characterized in that: The magnetic field sensor also includes an anti-interference module.

9. The magnetic field sensor according to claim 8, characterized in that: The voltage is applied in the vertical direction of the magnetic field sensor to adjust the range.

10. The magnetic field sensor according to claim 9, characterized in that: The bottom layer and the upper layer of the double-layer anomalous Hall effect thin film material respectively detect signals of different ranges, and the output signals are integrated through a dual-channel structure.

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