A magnetically sensitive thin film material, a sensor and a method of manufacturing the same

Abstract

This invention discloses a magnetically sensitive thin film material, a sensor, and its fabrication method. The magnetically sensitive thin film material is a nanocomposite oxide thin film with strong anomalous Hall effect and low hysteresis characteristics. The material itself has advantages such as high sensitivity, high temperature resistance, and oxidation resistance. The sensor of this invention can significantly improve the linearity of the anomalous Hall voltage response to an applied magnetic field by using an interface insertion layer design and non-solid solution doping. The interface insertion layer design improves the grain size of the magnetically sensitive thin film material; the self-assembly doping technique optimizes the linear response of the anomalous Hall voltage to an external magnetic field without reducing material performance or changing the fixed thickness of the film.

Description

Technical Field

[0001] This invention belongs to the field of magnetically sensitive thin film material technology, and particularly relates to a magnetically sensitive thin film material, sensor and its preparation and optimization methods with low hysteresis and wide range. Background Technology

[0002] Anomalous Hall magnetic field sensors have attracted widespread attention from researchers due to their superior sensitivity compared to Hall sensors. Compared to magnetoresistive sensors, anomalous Hall sensors possess the characteristic of remaining undamaged under larger applied magnetic fields, while retaining their inherent Z-axis sensitivity, giving them considerable development potential and competitiveness. However, current limitations on anomalous Hall magnetic field sensors include insufficient linearity and the need to improve hysteresis; furthermore, anomalous Hall sensors often employ precious metal materials, and their oxidation protection and cost are also considerations. The response speed of ferromagnetic metal materials affects their response to ultra-high testing frequencies. Against this backdrop, oxide-based anomalous Hall sensors, especially subferromagnetic half-metal oxide anomalous Hall sensors, have garnered attention. Their advantages lie in oxidation resistance and the absence of precious metals; however, the variable properties of oxide materials, especially when used as sensors, such as the large hysteresis of Fe3O4, limit their further applications. Therefore, it is necessary to investigate methods for fabricating low-hysteresis and wide-range oxide anomalous Hall effect thin-film sensors to optimize their linearity and range. Summary of the Invention

[0003] To address the shortcomings of existing oxide-based anomalous Hall sensors, such as high hysteresis and insufficient sensitivity and linearity, this invention provides an oxide anomalous Hall effect thin-film sensor with low hysteresis and a wide measurement range, along with its linearity-optimized fabrication method.

[0004] The present invention solves the above-mentioned technical problems through the following technical solution:

[0005] According to one aspect of the present invention, a magnetically sensitive thin film material is provided. The magnetically sensitive thin film material is a nanocomposite oxide thin film with strong anomalous Hall effect and low hysteresis characteristics. It is prepared into a Hall bar shape by an etching process, and the magnetic sensitivity characteristics are characterized by measuring the anomalous Hall effect.

[0006] According to another aspect of the present invention, a sensor is also provided, comprising:

[0007] Substrate, which is used to provide support for the device;

[0008] An interface insertion layer, disposed above the substrate, is used to control the size of the oxide nanocomposite film;

[0009] The oxide nanocomposite film, disposed above the interface insertion layer, is the aforementioned magnetically sensitive thin film material, comprising a first thin film functional phase and a second doped phase exhibiting a strong anomalous Hall effect.

[0010] Optionally, the oxide nanocomposite film is composed of two lattice-matched but non-solid-dissolved materials, and the substrate and the two phases in the oxide nanocomposite film have good lattice matching.

[0011] Optionally, the composition of the first thin film functional phase is greater than 70% of the total composition of the oxide nanocomposite thin film to ensure its strong anomalous Hall effect and good sensitivity.

[0012] Optionally, the substrate is MgAl2O4, the buffer layer is polycrystalline graphene, the first thin film functional phase is NiFeCoO4 (20 nm), and the second doped phase is NiO.

[0013] Optionally, the substrate is MgO, the buffer layer is polycrystalline graphene, the first thin film functional phase is Fe3O4 (30nm), and the second doped phase is 15% MgO.

[0014] Optionally, the interface insertion layer is a cross-shaped Holba structure.

[0015] Optionally, the orthographic projection size of the oxide nanocomposite film is the same as the orthographic projection size of the interface insertion layer.

[0016] According to another aspect of the present invention, a method for preparing a magnetically sensitive thin film material and a sensor is also provided, comprising the following steps:

[0017] Growing intercalation layer thin films or transferring two-dimensional material thin films on a substrate;

[0018] A nanocomposite magnetically sensitive thin film material is grown above the intercalation layer film;

[0019] A cross-shaped Holba structure of an interface insertion layer / nanocomposite magnetic sensitive film is achieved by photolithography or laser engraving to obtain the sensor described above.

[0020] Alternatively, the method for growing nanocomposite magnetically sensitive thin film materials is pulsed laser deposition or magnetron sputtering.

[0021] Compared with existing technologies, the present invention has the following advantages:

[0022] 1. The magnetically sensitive thin film material and sensor provided by this invention overcome the inherent large hysteresis of the material, significantly optimize its linearity, and expand its application prospects as an anomalous Hall sensor in the field of linear magnetic sensing. The interface insertion layer design and non-solid solution doping in the sensor can significantly improve the linearity of the anomalous Hall voltage response to an applied magnetic field in the magnetically sensitive thin film material. The grain size of the magnetically sensitive thin film material is improved through the insertion layer design; the self-assembly doping technique optimizes the linear response of the anomalous Hall voltage to an external magnetic field without significantly reducing material performance or changing the fixed thickness of the film.

[0023] 2. Compared with other conventional metal-based multilayer anomalous Hall sensors, the magnetically sensitive thin film material provided by this invention is cheaper, has fewer thin film layers, is simpler to prepare, and has the characteristics of high sensitivity, high temperature resistance, and oxidation resistance; the magnetic response speed of the semi-metal oxide ferrimagnetic material is theoretically higher than that of ferromagnetic metals.

[0024] 3. The method for preparing magnetically sensitive thin film materials and sensors provided by the present invention uses self-assembly doping technology and interface intercalation method to optimize the grain size of the material, which can achieve optimization without reducing the material performance or changing the fixed thickness of the thin film. Attached Figure Description

[0025] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of an oxide anomalous Hall effect thin film material and sensor with low hysteresis and wide range according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram illustrating the relationship between the material structure and doping of an oxide anomalous Hall effect with low hysteresis and wide range according to an embodiment of the present invention.

[0028] Figure 3 This is an anomalous Hall effect test curve of an oxide anomalous Hall effect thin film material with low hysteresis and wide range according to an embodiment of the present invention;

[0029] Figure 4 This is an anomalous Hall effect test curve of another oxide anomalous Hall effect thin film material with low hysteresis and wide range according to an embodiment of the present invention;

[0030] Figure 5This is a process flow diagram of the fabrication of an oxide anomalous Hall effect thin film material and sensor with low hysteresis and wide range according to an embodiment of the present invention.

[0031] Among them, 101 is the substrate; 102 is the interface insertion layer; and 103 is the oxide nanocomposite film. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0033] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. Where the terms "first," "second," and "third" are used for descriptive purposes and to distinguish technical features, they should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The embodiments of this invention will now be described according to its overall structure.

[0035] Example 1

[0036] The present invention provides a magnetically sensitive thin film material, which is a nanocomposite oxide thin film with strong anomalous Hall effect and low magnetic hysteresis characteristics. It is prepared into a Hall bar shape by etching process, and the magnetic sensitivity characteristics are characterized by measuring the anomalous Hall effect.

[0037] Example 2

[0038] like Figure 1As shown, the present invention provides a magnetically sensitive thin film material and sensor with low hysteresis and wide measurement range, comprising: a substrate 101, an interface insertion layer 102, and an oxide nanocomposite thin film 103. The substrate 101 provides support for the device. The interface insertion layer 102 is disposed above the substrate 101 and is used to control the grain size of the oxide nanocomposite thin film 103. The oxide nanocomposite thin film 103 is disposed above the interface insertion layer 102 and is the aforementioned magnetically sensitive thin film material, composed of a first thin film functional phase and a second doped phase with a strong anomalous Hall effect. After doping with the second doped phase, the number of grain boundaries in the thin film increases, the hysteresis decreases, and the linearity improves. The thin film and magnetic field sensor are located in the XY plane, with the vertical direction being the Z-axis, i.e., the magnetic sensing axis. The thin black lines in the figure represent conductive films or wires.

[0039] The interface insertion layer 102 has a cross-shaped Holba structure. The orthographic projection size of the oxide nanocomposite film 103 is the same as that of the interface insertion layer 102.

[0040] like Figure 2 As shown, the oxide nanocomposite film 103 is composed of two lattice-matched but non-solid-dissolved materials. Both phases in the substrate 101 and the oxide nanocomposite film 103 have good lattice matching to ensure that both phases can achieve good epitaxial growth on the substrate 101 layer. The doped material can refine the grains, thereby reducing the magnetic anisotropy of the material and improving the linearity of the sensor.

[0041] The composition of the first thin-film functional phase in the two-phase system should be greater than 70% of the total composition of the oxide nanocomposite film 103 to ensure a strong anomalous Hall effect and good sensitivity. A higher proportion of the first thin-film functional phase results in a stronger anomalous Hall effect and higher sensitivity, but linearity will decrease; conversely, a lower proportion will increase linearity but decrease sensitivity. In practical design, the optimal ratio is related to the material composition.

[0042] In one embodiment, the first thin film functional phase is NiFeCoO4 (20 nm), the substrate 101 is MgAl2O4, the buffer layer is commercial polycrystalline graphene, and the second doped phase is NiO, such as... Figure 3 The anomalous Hall effect test curve is shown. It can be seen that the hysteresis is very large when undoped, making it unsuitable as a magnetic field sensor. However, it achieves better overall sensitivity and linearity (sensitivity ~94 V·A in the 300 Gs range) when doped with 10%. -1 ·T -1 Before doping, the hysteresis loop is large and there is no linear range; when the doping ratio is too high, the amplitude of its anomalous Hall effect, i.e., the sensitivity, drops sharply.

[0043] In another embodiment, the first thin film functional phase is Fe3O4 (30 nm), the second doped phase is MgO, the substrate 101 is MgO, and the buffer layer is commercially available polycrystalline graphene, such as... Figure 4 As shown, before doping, this material exhibits insufficient phenotype as a magnetic field sensor due to its large hysteresis; however, when doped with 15% MgO, it demonstrates better sensitivity and linearity (sensitivity ~17.6 V·A in the 6000 Gs range). -1 ·T -1 The decrease in sensitivity was not significant.

[0044] Example 3

[0045] like Figure 5 This paper describes a method for fabricating an oxide anomalous Hall effect thin-film sensor with low hysteresis and a wide measurement range. The method for growing the nanocomposite magnetically sensitive thin-film material is pulsed laser deposition or magnetron sputtering. Before growth, the anomalous Hall effect material phase and the doped phase are weighed, mixed, ball-milled, and granulated according to a standard ceramic target preparation process to prepare a standard target material.

[0046] Includes the following steps:

[0047] Growing intercalation layer thin films or transferring two-dimensional material thin films on a substrate;

[0048] A nanocomposite magnetically sensitive thin film material is grown above the intercalation layer film;

[0049] The cross-shaped Holba structure of the interface insertion layer / nanocomposite magnetic sensitive film is realized by photolithography or laser engraving, wherein the nanocomposite magnetic sensitive film is an oxide nanocomposite film, thus obtaining the above-mentioned sensor.

[0050] The above description only discloses specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or modifications that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A sensor, characterized by include: Substrate, which is used to provide support for the device; An interface insertion layer, disposed above the substrate, is used to control the size of the oxide nanocomposite film; The oxide nanocomposite film, disposed above the interface insertion layer, is a magnetically sensitive thin film material, comprising a first film functional phase and a second doped phase with a strong anomalous Hall effect; The magnetically sensitive thin film material is a nanocomposite oxide thin film with strong anomalous Hall effect and low magnetic hysteresis characteristics. It is prepared into a Hall bar shape by etching process, and the magnetic sensitivity characteristics are characterized by measuring the anomalous Hall effect. The oxide nanocomposite film is composed of two lattice-matched but non-solid-dissolved materials, and the substrate and the two phases in the oxide nanocomposite film have good lattice matching.

2. The sensor of claim 1, wherein, The composition of the first thin film functional phase is greater than 70% of the total composition of the oxide nanocomposite thin film, in order to ensure its strong anomalous Hall effect and good sensitivity.

3. The sensor of claim 1, wherein, The substrate is MgAl2O4, the buffer layer is polycrystalline graphene, the first thin film functional phase is NiFeCoO4, and the second doped phase is NiO.

4. The sensor of claim 1, wherein, The substrate is MgO, the buffer layer is polycrystalline graphene, the first thin film functional phase is Fe3O4, and the second doped phase is 15% MgO.

5. The sensor of claim 1, wherein, The interface insertion layer is a cross-shaped Holba structure.

6. The sensor of claim 1, wherein, The orthographic projection size of the oxide nanocomposite film is the same as the orthographic projection size of the interface insertion layer.

7. A method for producing a magnetically sensitive thin film material, sensor, characterized in that Includes the following steps: Growing intercalation layer thin films or transferring two-dimensional material thin films on a substrate; Among them, the anomalous Hall effect material phase and the doped phase are weighed, mixed, ball-milled and granulated according to the chemical ratio to prepare the standard ceramic target material through the standard ceramic target material preparation process. A nanocomposite magnetically sensitive thin film material is grown on top of the intercalation layer film using the standard target material; A cross-shaped Holba structure of an interface insertion layer / nanocomposite magnetic sensitive film is achieved by photolithography or laser engraving, thereby obtaining the sensor described in any one of claims 1-6.

8. The method of claim 7, wherein the magnetic sensitive thin film material and sensor are prepared by the steps of: (a) preparing a solution of the magnetic sensitive thin film material; (b) coating the solution on a substrate; (c) drying the solution; and (d) removing the substrate. The methods for growing nanocomposite magnetically sensitive thin film materials are pulsed laser deposition or magnetron sputtering.

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