Magnetic sensor and magnetic measurement method

Abstract

The present invention provides a magnetic sensor and a magnetic measurement method capable of removing 1 / f noise and measuring small magnetic fields with high accuracy. [Solution] A magnetic sensor characterized by comprising a variable magnetic field detection unit having a Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect, and a magnetic field control unit that controls the Hall element so that a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction is generated in the Hall element, and may further comprise a magnetic field calculation unit that calculates a measured magnetic field based on a first output including a measurement result when the variable magnetic field detection unit measures a measured magnetic field along the magnetic sensing direction in a first state in which the direction of the magnetic field generated in the Hall element is not controlled by the magnetic field control unit, and a second output including a measurement result when the variable magnetic field detection unit measures the measured magnetic field in a second state in which the direction of the magnetic field generated in the Hall element is controlled by the magnetic field control unit.

Description

[Technical field]

[0001] The present invention relates to a magnetic sensor including a magnetoresistive element and a magnetic measurement method. [Background technology]

[0002] Some magnetic sensors that detect and measure magnetic fields are equipped with a magnetoresistance effect element that uses the GMR (giant magnetoresistance) effect or the TMR (tunneling magnetoresistance) effect. The magnetoresistance effect element in these magnetic sensors has a structure in which a fixed magnetic layer, a non-magnetic intermediate layer, and a free magnetic layer are laminated in this order. In the magnetoresistance effect element, when an external magnetic field to be measured is applied, the magnetization direction of the free magnetic layer changes, and a resistance change occurs according to the angle between the magnetization direction of the free magnetic layer and the magnetization direction of the fixed magnetic layer. A magnetic sensor equipped with a magnetoresistance effect element can detect a magnetic field using the resistance change of the magnetoresistance effect element.

[0003] Magnetic sensors equipped with magnetoresistance effect elements have 1 / f noise that cannot be removed by filters. 1 / f noise is inversely proportional to frequency and becomes larger as the frequency decreases, so it can be an obstacle to high-precision measurements. For this reason, various methods are used to remove 1 / f noise.

[0004] Patent Document 1 discloses an even-function magnetic sensor that removes 1 / f noise by taking the difference between the output when a bias magnetic field is applied in a certain direction (+X direction) and the output when a bias magnetic field is applied in the opposite direction (-X direction).

[0005] Patent Document 2 discloses a measuring device that, when measuring the Hall electromotive force of a semiconductor sample, shifts the frequency band of the voltage difference to the lower frequency side in order to remove noise caused by a Schottky barrier that occurs between an electrode and a sample, thereby removing the frequency band of the voltage difference that is significantly affected by 1 / f noise.

[0006] Patent document 3 discloses a magnetic field sensing device that samples bridge signals at a first current and a second current by switching between two sample holds, and determines the value of the magnetic field from the difference between the sampled first and second bridge signals.

[0007] Patent Document 4 discloses a sensor device that uses a modulator to switch the positive and negative sides of a sensor signal and obtain a difference between the modulated signals in order to remove 1 / f noise from the output signal. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2018-115972 A [Patent Document 2] JP 2020-148727 A [Patent Document 3] Special Publication No. 2012-518788 [Patent Document 4] Special Publication No. 2009-544004 Summary of the Invention [Problem to be solved by the invention]

[0009] A magnetic sensor equipped with a magnetoresistance effect element has a problem in that 1 / f noise in the low frequency range reduces the detection accuracy of the magnetic sensor, and various devices and methods have been proposed to solve this problem. The object of the present invention is to provide a magnetic sensor equipped with a magnetoresistance effect element and a magnetic measurement method that can remove 1 / f noise using a configuration different from the conventional one and measure small magnetic fields with high accuracy. [Means for solving the problem]

[0010] In one aspect, the present invention is a magnetic sensor characterized by comprising a variable magnetic field detection unit having a Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect, and a magnetic field control unit that controls the Hall element so that a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction is generated in the Hall element.

[0011] Magnetic sensors using Hall elements can now improve their magnetic detection sensitivity by utilizing the anomalous Hall effect based on ferromagnetic materials. Furthermore, in recent years, materials capable of generating virtual magnetic fields, such as topological antiferromagnets, have been discovered, and it is expected that the magnetic detection sensitivity of magnetic sensors using Hall elements will be further improved by using such materials as the constituent materials of the Hall elements. By adding a magnetic field control section to a magnetic sensor having a Hall element with improved magnetic detection sensitivity, it becomes possible to apply noise removal measures such as interphase double sampling (CDS). This can particularly improve the magnetic resolution of the magnetic sensor.

[0012] From the viewpoint of realizing CDS, the magnetic sensor may further include a magnetic field calculation unit that calculates the measured magnetic field based on a first output including a measurement result when the variable magnetic field detection unit measures a measured magnetic field along the magnetic sensing direction in a first state in which the direction of the magnetic field generated in the Hall element is not controlled by the magnetic field control unit, and a second output including a measurement result when the variable magnetic field detection unit measures the measured magnetic field in a second state in which the direction of the magnetic field generated in the Hall element is controlled by the magnetic field control unit. When the magnetic field generated in the Hall element controlled by the magnetic field control unit in the second state has a component in a blind direction perpendicular to the magnetic sensing direction, preferably along the blind direction, the intensity of the measured magnetic field in the second output is weaker than the intensity of the measured magnetic field in the first output, so that 1 / f noise can be removed by CDS using the first output and the second output.

[0013] In the above magnetic sensor, the magnetic field control unit may generate a spin orbit torque when current is applied, and in this case, the Hall element generates a magnetic field having a component in the insensitive direction based on the spin orbit torque.

[0014] In the magnetic sensor, the Hall element and the magnetic field control unit may be electrically connected, and a circuit for supplying current to the magnetic field control unit and a circuit for measuring a Hall voltage generated in the Hall element may be at least partially common. This allows the magnetic sensor to be miniaturized.

[0015] In the above magnetic sensor, the magnetic field calculation unit may perform processing that includes subtracting a second adjusted output obtained by removing a signal corresponding to a voltage applied to the magnetic field control unit to control the Hall element from the second output, to obtain a signal indicative of the measured magnetic field.

[0016] In the magnetic sensor, the Hall element and the magnetic field control unit may be magnetically coupled, whereby the magnetic field control unit can stably control the magnetic state of the Hall element.

[0017] The magnetic sensor may further include a bias magnetic field source that sets the magnetic field generated in the Hall element in a direction intersecting the magnetic sensing direction in a non-magnetic field state where a measurement magnetic field is not applied, thereby reducing hysteresis of the magnetic sensor.

[0018] In the magnetic sensor, the Hall element and the magnetic field control unit may form a laminated structure, in which the magnetic field control unit is formed by laminating a spin torque generation unit that generates a spin orbit torque when a current is applied, and an anisotropy variable unit that generates a magnetic field having a component in the insensitive direction based on the spin orbit torque from the spin torque generation unit, and the anisotropy variable unit may be magnetically coupled to the Hall element.

[0019] In the magnetic sensor having the above-mentioned laminated structure, the magnetic field control unit may have an electromagnetic field control unit that generates a magnetic field having a component in the insensitive direction by energization, and the electromagnetic field control unit may be magnetically coupled to the Hall element. The relationship between the lamination direction (element lamination direction) of the Hall element and the magnetic field control unit and the magnetic sensing direction and the insensitive direction is appropriately set. Either the magnetic sensing direction or the insensitive direction may be aligned with the element lamination direction, or both the magnetic sensing direction and the insensitive direction may be perpendicular to the element lamination direction.

[0020] In another aspect, the present invention provides a magnetic measurement method using a magnetic sensor including a variable magnetic field detection unit that measures a measured magnetic field and a magnetic field calculation unit that calculates the measured magnetic field based on an output from the variable magnetic field detection unit. The variable magnetic field detection unit includes a Hall element having a magnetic sensitivity direction that exhibits an anomalous Hall effect, and a magnetic field control unit that controls the Hall element so that a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensitivity direction is generated in the Hall element. The magnetic measurement method includes a first measurement step of obtaining a first output from the variable magnetic field detection unit, the first output including a measurement result in a first state in which the direction of the magnetic field generated in the Hall element is not controlled by the magnetic field control unit, a second measurement step of obtaining a second output from the variable magnetic field detection unit, the second output including a measurement result in a second state in which the direction of the magnetic field generated in the Hall element is controlled by the magnetic field control unit, and a magnetic field calculation step of calculating the measured magnetic field from the first output and the second output in the magnetic field calculation unit. Effect of the Invention

[0021] According to the present invention, since 1 / f noise can be removed from a measured magnetic field, it is possible to provide a magnetic sensor and a magnetic measurement method having high magnetic resolution and capable of measuring a small magnetic field with high accuracy. [Brief description of the drawings]

[0022] [Figure 1] 1 is a block diagram of a magnetic sensor according to an embodiment of the present invention; [Diagram 2]3A and 3B are diagrams illustrating a variable magnetic field detection unit (in a no magnetic field state) included in the magnetic sensor according to the first embodiment of the present invention. [Diagram 3] 2A to 2C are diagrams illustrating a variable magnetic field detection unit (Hall element in a first state) included in the magnetic sensor according to the first embodiment of the present invention. [Figure 4] 3A to 3C are diagrams illustrating a variable magnetic field detection unit (Hall element in a second state) included in the magnetic sensor according to the first embodiment of the present invention. [Diagram 5] 4 is a flowchart illustrating a magnetic measurement method using the magnetic sensor according to the first embodiment of the present invention. [Figure 6] 4 is a timing chart illustrating a magnetic measurement method using the magnetic sensor according to the first embodiment of the present invention. [Figure 7] 5A to 5C are explanatory diagrams of modified examples of the variable magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. [Figure 8] 13 is a diagram illustrating a first example (no magnetic field state) of a variable magnetic field detection unit included in a magnetic sensor according to a second embodiment of the present invention. FIG. [Figure 9] 10 is a diagram illustrating a first example of a variable magnetic field detection unit included in a magnetic sensor according to a second embodiment of the present invention (Hall element is in a first state). FIG. [Figure 10A] 13 is a diagram illustrating a first example of a variable magnetic field detection unit included in a magnetic sensor according to a second embodiment of the present invention (Hall element in a second state). FIG. [Figure 10B] 10B is an XY plan view illustrating the Lorentz force acting on a current flowing through the Hall element shown in FIG. 10A. [Figure 11] 13 is a diagram illustrating a second example of the variable magnetic field detection unit included in the magnetic sensor according to the second embodiment of the present invention (Hall element in a second state). FIG. [Figure 12] 13 is a diagram illustrating a variable magnetic field detection unit (in a no magnetic field state) included in the magnetic sensor according to the modified example of the first embodiment of the present invention. FIG. [Figure 13] 4A to 4C are diagrams illustrating a variable magnetic field detection unit (Hall element in a first state) included in the magnetic sensor according to the modified example of the first embodiment of the present invention. [Figure 14]5 is a diagram illustrating a variable magnetic field detection unit (Hall element is in a second state) included in the magnetic sensor according to the modified example of the first embodiment of the present invention. FIG. [Figure 15] 1A and 1B are diagrams illustrating an example of a case in which a magnetic field based on exchange coupling involving an antiferromagnetic material is used as a bias magnetic field source for controlling the direction of a magnetic field generated in a Hall element in a no-magnetic-field state. [Figure 16] 11A and 11B are diagrams illustrating another example in which a magnetic field based on exchange coupling involving an antiferromagnetic material is used as a bias magnetic field source for controlling the direction of a magnetic field generated in a Hall element in a no-magnetic-field state. [Figure 17] 11A and 11B are diagrams illustrating another example in which a magnetic field based on exchange coupling involving an antiferromagnetic material is used as a bias magnetic field source for controlling the direction of a magnetic field generated in a Hall element in a no-magnetic-field state. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In each drawing, the same components are given the same reference numerals and the description will be omitted. In order to show the positional relationship of each component, reference coordinates are appropriately shown in each drawing.

[0024] Fig. 1 is a block diagram of a magnetic sensor according to an embodiment of the present invention. Fig. 2 is an explanatory diagram of a variable magnetic field detection unit (no magnetic field state) provided in the magnetic sensor according to an embodiment of the present invention. The magnetic sensor 1 of this embodiment includes a variable magnetic field detection unit 2, a control power supply 3, a magnetic field calculation unit 4, an amplifier 5, an analog-digital conversion circuit (A / D conversion circuit 6), and a control unit 7. The control unit 7 controls each unit constituting the magnetic sensor 1, and is configured as a CPU (central processing unit), a program, etc.

[0025] The variable magnetic field detection unit 2 detects an external magnetic field (measurement magnetic field H) as a measurement target, and includes a Hall element 10 exhibiting an anomalous Hall effect and a magnetic field control unit 20 that controls a magnetic field 10m generated by the Hall element 10, as described below. The control power supply 3 applies a predetermined current or a predetermined voltage to each unit based on a control signal from the control unit 7, and includes a supply power supply Vb and a measurement power supply Vm, which will be described later.

[0026] The magnetic field calculation unit 4 calculates the measured magnetic field H based on the output of the variable magnetic field detection unit 2, and is configured, for example, with a CDS (Correlated Double Sampling) circuit. The magnetic field calculation unit 4 calculates the measured magnetic field H based on a first output from the variable magnetic field detection unit 2 when the Hall element 10, which will be described later, is in a first state, and a second output from the variable magnetic field detection unit 2 when the Hall element 10 is in a second state. For example, 1 / f noise can be removed from the first output by calculating the difference between a signal based on the first output and a signal based on the second output.

[0027] In the magnetic sensor 1, after the magnetic field calculation unit 4 calculates the measured magnetic field H, the signal corresponding to the calculated measured magnetic field H is amplified by the amplifier 5 and then converted into digital data by the A / D conversion circuit 6.

[0028] (First embodiment) Fig. 2 is a diagram for explaining a variable magnetic field detection unit (no magnetic field state) included in the magnetic sensor according to the first embodiment of the present invention. Fig. 3 is a diagram for explaining a variable magnetic field detection unit (Hall element in a first state) included in the magnetic sensor according to the first embodiment of the present invention. Fig. 4 is a diagram for explaining a variable magnetic field detection unit (Hall element in a second state) included in the magnetic sensor according to the first embodiment of the present invention.

[0029] The variable magnetic field detection unit 2 of the magnetic sensor 1 according to this embodiment includes a Hall element 10 having a magnetic sensing direction that exhibits an anomalous Hall effect, and a magnetic field control unit 20 that controls the Hall element 10 so that a magnetic field 10m having a component of an insensitive direction perpendicular to the magnetic sensing direction is generated in the Hall element 10. In this embodiment, the magnetic sensing direction of the Hall element 10 is along the Z direction along the stacking direction (element stacking direction) of the Hall element 10 and the magnetic field control unit 20. The insensitive direction is the direction of an external magnetic field in which the Hall element 10 does not exhibit an anomalous Hall effect, and as described above, the insensitive directions are two directions (X direction, Y direction) perpendicular to the magnetic sensing direction. In this embodiment, a specific example is taken of the insensitive direction being along the X direction, which is one of the directions perpendicular to the element stacking direction.

[0030] The material constituting the Hall element 10 is not limited as long as it is possible to generate an anomalous Hall effect in the Hall element 10 when it receives a magnetic field in the magnetic sensing direction. Specific examples of such materials include ferromagnetic materials such as Fe-Ni alloys and Fe-Si alloys, Heusler alloys such as Co2MnAl, semi-magnetic semiconductors such as CdMnTe, magnetic Weyl semimetals such as Co3Sn2S2, Mn3X (X = Sn, Ge, Ga, Rh, Pt, Ir), Mn 1-x Tr x Examples include antiferromagnetic materials such as gamma-phase (Tr = Ni, Fe, Cu, Ru, Pd, Ir, Rh, Pd, Pt).

[0031] The magnetic field 10m generated in the Hall element 10 exhibiting the anomalous Hall effect may be based on the magnetization of the material constituting the Hall element 10, or may be based on a virtual magnetic field generated by the magnetic structural characteristics of the material constituting the Hall element 10. A ferromagnetic material is exemplified as a material for the Hall element 10 corresponding to the former case (magnetization), and a topological antiferromagnet is exemplified as a material for the Hall element 10 corresponding to the latter case (virtual magnetic field).

[0032] In this embodiment, both the Hall element 10 and the magnetic field control unit 20 are film-like bodies, and have a laminated structure stacked in the Z direction. The Hall element 10 may be composed of a single layer film or a laminated film. In the case of a laminated film, a boundary region may be generated between adjacent films. In the case of a laminated film, at least one of the constituent films may be composed of a material that exhibits the anomalous Hall effect.

[0033] A first circuit 60 including a power supply Vb for supplying the Hall element 10 with electric charge subjected to the Lorentz force F, and a second circuit 61 for measuring a Hall voltage generated in the Hall element 10 as a result of the electric charge being subjected to the Lorentz force F, are connected to the Hall element 10. A measurement power supply Vm provided in the second circuit 61 has a voltage measurement function. In this embodiment, electrodes related to the first circuit 60 are provided at both ends of the Hall element 10 in the X direction. In this embodiment, the Hall element 10 and the magnetic field control unit 20 are electrically connected, and therefore electrodes related to the second circuit 61 are provided at both ends of a part of the magnetic field control unit 20 (a spin torque generating unit 21 described later) in the Y direction.

[0034] In this embodiment, the magnetic field control unit 20 generates a spin orbit torque by energizing, and a magnetic field 10m having a component in the X direction (insensitive direction) is generated in the Hall element 10 based on the spin orbit torque. In this embodiment, the magnetic field control unit 20 is formed by stacking a spin torque generation unit 21 that generates a spin orbit torque when energized, and an anisotropy variable unit 22 that generates a magnetic field 20m having a component in the X direction (insensitive direction) based on the spin orbit torque from the spin torque generation unit 21. The anisotropy variable unit 22 is magnetically coupled to the Hall element 10, and thus the spin torque generation unit 21 controls the direction of the magnetic field 10m generated in the Hall element 10 via the anisotropy variable unit 22.

[0035] The spin torque generating unit 21 exerts the spin Hall effect, the Rashba-Edelstein effect, and the like by passing a current in the XY in-plane direction, which is the Y direction in this embodiment, and applies a spin orbit torque to the anisotropy variable unit 22. Materials constituting the spin torque generating unit 21 include heavy metals (5d transition metals) such as Hf, Ta, W, Pt, and Ir, which have a high specific gravity among paramagnetic transition metals; topological insulators such as BiSb, BiSe, Bi2Se3, and Bi2Te3; Mn3X (X=Sn, Ge, Ga, Rh, Pt, Ir), Mn 1-x Tr x Examples include antiferromagnetic materials such as gamma-phase (Tr = Ni, Fe, Cu, Ru, Pd, Ir, Rh, Pd, Pt); half-Heusler alloy topological semimetals such as LuPtSb, LuPdBi, LuPtBi, ScPtBi, YAuPb, LaPtBi, CePtBi, ThPtPb, and LaAuPb, as well as mixed crystals of these.

[0036] In a specific example shown in FIG. 2, the spin torque generating unit 21 is a film-like body, and this film-like body may be composed of a single structure, that is, a single layer film, or may be composed of a laminated film. In the case of a laminated film, a boundary region may be generated between adjacent films. The spin torque generating unit 21 may be composed entirely of a single material, or may be composed of multiple materials. In the case of being composed of multiple materials, it may have a laminated structure as described above, or may have a dispersed structure. In the case of having a dispersed structure, the degree of dispersion is arbitrary, and it may be a structure in which nanocrystals are dispersed, or a certain pattern may be formed. In addition, a compositional distribution may be set in the spin torque generating unit 21.

[0037] The anisotropy variable part 22 can generate a magnetic field 20m having a component in the X direction (the insensitive direction in this embodiment) based on the spin orbit torque from the spin torque generation part 21 (see FIG. 4). Since the anisotropy variable part 22 is magnetically coupled to the Hall element 10, when the magnetic field 20m is generated in the anisotropy variable part 22 based on the spin orbit torque from the spin torque generation part 21, a magnetic field 10m having a component in the X direction (the insensitive direction) is also generated in the Hall element 10 (see FIG. 4). Note that in FIG. 2, the spin orbit torque is not applied from the spin torque generation part 21 to the anisotropy variable part 22, and the measurement magnetic field H is not applied, so the magnetic field 20m of the anisotropy variable part 22 can be in the X1 direction due to the influence of the magnetic field 10m of the Hall element 10 to which it is magnetically coupled.

[0038] The anisotropy variable part 22 may be made of any material as long as it can generate a magnetic field having an X-direction (insensitive direction) when subjected to spin orbit torque. The anisotropy variable part 22 may be made of a ferromagnetic material or an antiferromagnetic material. Examples of such materials include soft magnetic materials such as CoFe alloys and NiFe alloys (nickel-iron alloys); and antiferromagnetic materials such as Mn3X (X=Sn, Ge, Ga, Rh, Pt, Ir).

[0039] In a specific example shown in FIG. 2, the anisotropy variable part 22 is a film-like body, and this film-like body may be composed of a single structure, that is, a single layer film, or may be composed of a laminated film. In the case of a laminated film, a boundary region may be generated between adjacent films. The anisotropy variable part 22 may be composed entirely of a single material, or may be composed of multiple materials. In the case of being composed of multiple materials, it may have a laminated structure as described above, or may have a dispersed structure. In the case of having a dispersed structure, the degree of dispersion is arbitrary, and it may be a structure in which nanocrystals are dispersed, or a certain pattern may be formed. In addition, a compositional distribution may be set in the anisotropy variable part 22.

[0040] In this embodiment, the Hall element 10 is laminated with a permanent magnet layer 30 as a bias magnetic field source, and in a magnetic field-free state in which the measurement magnetic field H is not applied as shown in FIG. 2, the direction of the magnetic field 10m generated in the Hall element 10 is along the direction of the magnetization 30m of the permanent magnet layer 30 (X1 direction). The direction of the magnetic field 10m (X direction) is one of the insensitive directions and is parallel to the direction of the current 10c flowing through the Hall element 10 by the power supply Vb of the first circuit 60, so that the Lorentz force does not act on the charge (electrons) of the current 10c, and no Hall voltage is generated based on the magnetic field 10m. In addition, the material constituting the Hall element 10 is easily magnetized by the bias magnetic field based on the magnetization 30m of the permanent magnet layer 30. Therefore, the hysteresis characteristic of the magnetic sensor 1 is likely to be good. The bias magnetic field source is not limited to a permanent magnet, and may be a structure that generates an induced magnetic field by current flowing through a coil or a magnetic field based on exchange coupling involving an antiferromagnetic material.

[0041] (First state) The first state shown in Figure 3 is a state in which the direction of the magnetic field 10m generated in the Hall element 10 is not controlled by the magnetic field control unit 20, and the variable magnetic field detection unit 2 outputs a first output including the measurement result when measuring the measurement magnetic field H along the Z direction (magnetic sensing direction) in the first state.

[0042] In this embodiment, a current 10c from a power supply Vb that supplies electrons as charges receiving the Lorentz force F flows through the Hall element 10 in the X2 direction. In this state, the Hall element 10 receives a measurement magnetic field H in the Z direction (magnetic sensing direction), and a magnetic field 10m having a large component in the Z direction is generated in the Hall element 10, which causes the Hall element 10 to exhibit the anomalous Hall effect. If the Hall element 10 is made of a ferromagnetic material, the magnetic field 10m includes the magnetization of the Hall element 10. If the Hall element 10 is made of a topological antiferromagnetic material, the magnetic field 10m includes a virtual magnetic field derived from the Berry curvature present in the reciprocal space. Since the intensity of the magnetic field 10m thus generated is greater than the measurement magnetic field H, the Hall element 10 exhibiting the anomalous Hall effect has a function of amplifying the measurement magnetic field H.

[0043] This magnetic field 10m exerts a Lorentz force F in the Y2 direction on the electrons carrying the current 10c. As described above, the Hall element 10 and the magnetic field control unit 20 are electrically connected, so that the Hall voltage based on the Lorentz force F generated in the Hall element 10 is measured in the second circuit 61 provided with a measurement power source Vm having a voltage measurement function through an electrode provided at the end of the magnetic field control unit 20 in the Y direction, and a signal including this measurement result is output from the variable magnetic field detection unit 2 as the first output.

[0044] When the relative permeability of the anisotropy variable part 22 is greater than 1, the anisotropy variable part 22 is magnetized by receiving the measurement magnetic field H, and a magnetic field 20m generated in the anisotropy variable part 22 under the influence of the magnetization reaches the Hall element 10, helping to generate a predetermined magnetic field 10m in the Hall element 10. That is, in this case, the anisotropy variable part 22 functions as a yoke for the Hall element 10.

[0045] In addition, since the magnetization 30m of the permanent magnet layer 30 acts on the Hall element 10 even in the first state, the magnetic field 10m generated in the Hall element 10 may have a component in the X1 direction due to the influence of the magnetization 30m. Even in this case, the direction of the magnetization 30m (X direction) is parallel to the direction of the current 10c and is one of the insensitive directions, so no Hall voltage is generated based on the magnetization 30m. In other words, the magnetization 30m of the permanent magnet layer 30 does not affect the measurement value of the measured magnetic field H included in the first output.

[0046] (Second state) The second state shown in Figure 4 is a state in which the direction of the magnetic field 10m generated in the Hall element 10 is controlled by the magnetic field control unit 20, and the variable magnetic field detection unit 2 outputs a second output including the measurement result when measuring the measured magnetic field H in the second state.

[0047] In this embodiment, in the second state, the current 20c from the second circuit 61 having the measurement power supply Vm is in the Y1 direction. This current 20c generates a spin current 20s in the spin torque generating unit 21, and the spin orbit torque generated by this spin current 20s generates a magnetic field 20m in the X1 direction in the anisotropy variable unit 22. Influenced by the magnetic field 20m generated in the anisotropy variable unit 22, the magnetic field 10m generated in the Hall element 10 magnetically coupled to the anisotropy variable unit 22 has a component in the X1 direction along the magnetic field 20m that is larger than the component in the Z1 direction along the measurement magnetic field H. That is, in the Hall element 10, a strong magnetic field is generated along the X direction (insensitive direction). As a result, even if the Hall element 10 receives the measurement magnetic field H along the Z direction (magnetic sensing direction), the anomalous Hall effect is not clearly shown, and the sensitivity of the measurement magnetic field H is reduced. 3 and 4, in the second state, the Lorentz force F acting on the current 10c flowing through the Hall element 10 is smaller than that in the first state. As a result, the Hall voltage measured in the second circuit 61 is smaller, and a signal including this measurement result is output from the variable magnetic field detection unit 2 as the second output.

[0048] It should be noted that the magnetization 30m of the permanent magnet layer 30 acts on the Hall element 10 even in the second state. However, since the direction of the magnetization 30m (X direction) is parallel to the direction of the magnetic field 20m of the anisotropy variable section 22 and is one of the insensitive directions, the magnetization 30m, together with the magnetic field 20m, contributes to the magnetic field 10m having a component in the X direction (insensitive direction).

[0049] (Magnetic measurement method) FIG. 5 is a flowchart illustrating a magnetic measurement method using a magnetic sensor according to a first embodiment of the present invention. FIG. 6 is a timing chart illustrating a magnetic measurement method using a magnetic sensor according to a first embodiment of the present invention. In this measurement method, as shown in FIG. 5, first, in a first measurement step, a control signal output from the control unit 7 controls the control power supply 3 so that the Hall element 10 included in the variable magnetic field detection unit 2 is in a first state. Specifically, the control unit 7 controls the measurement power supply Vm so that a current 20c does not flow through the magnetic field control unit 20.

[0050] In this way, the Hall element 10 is put in the first state, a current 10c is passed from the supply power source Vb to the Hall element 10, and the voltage is measured at the measurement power source Vm. The measured voltage is equal to the Hall voltage generated in the Hall element 10. A signal including this measurement result is output as a first output from the variable magnetic field detection unit 2 (step S101). Data indicating the first output output from the variable magnetic field detection unit 2 is input to the magnetic field calculation unit 4 and stored in the magnetic field calculation unit 4 or in a memory not shown.

[0051] Next, as a second measurement step, the control unit 7 controls the control power supply 3 so that the Hall element 10 of the variable magnetic field detection unit 2 is in the second state by a control signal output from the control unit 7. Specifically, the control unit 7 controls the measurement power supply Vm so that a current 20c flows through the magnetic field control unit 20.

[0052] In this way, the Hall element 10 is put into the second state, a current 10c is passed from the supply power source Vb to the Hall element 10, and the voltage is measured at the measurement power source Vm. The measured voltage is equal to the sum of the voltage Vs applied to pass the current 20c to the magnetic field control unit 20 and the Hall voltage generated in the Hall element 10. A signal including this measurement result is output as a second output from the variable magnetic field detection unit 2 (step S102). Data indicating the second output output from the variable magnetic field detection unit 2 is input to the magnetic field calculation unit 4 and stored in the magnetic field calculation unit 4 or in a memory not shown.

[0053] The measurement times of steps S101 and S102 are both sufficiently shorter than 1 microsecond (e.g., 0.01 microseconds), and the time required for steps S101 and S102 is also sufficiently shorter than 1 microsecond (e.g., 0.03 microseconds). Therefore, steps S101 and S102 are performed in an environment where the 1 / f noises are substantially equal, and the 1 / f noise included in the first output and the 1 / f noise included in the second output are substantially equal.

[0054] In the timing chart shown in Fig. 6, the Hall element 10 is repeatedly switched between the first state and the second state for a predetermined period. Specifically, the Hall element 10 is first set to the first state, and the Hall voltage generated by the magnetic field 10m based on the anomalous Hall effect is measured by the measurement power supply Vm, and the result is the first output. Then, in the second state, the voltage Vs for generating spin torque is applied from the measurement power supply Vm to set the Hall element 10 to the second state (see Fig. 6(a)), and a voltage including this voltage Vs is measured by the measurement power supply Vm, and the result is the second output (see Fig. 6(b)).

[0055] The magnetic field calculation unit 4 reads out data stored in the magnetic field calculation unit 4 or a memory (not shown) in steps S101 and S102, and performs a process of calculating a measured magnetic field H based on a signal based on the first output and a signal based on the second output as a magnetic field calculation step (step S103). In this process, not only is the second output subtracted from the first output, but a process of removing the voltage Vs included in the second output is first performed, thereby obtaining a second adjusted output. In the timing chart shown in FIG. 6(c), a voltage V1 based on the first output and a voltage V2 based on the second adjusted output are shown. By taking the difference between the first output and the second adjusted output (V1-V2), 1 / f noise is appropriately removed from the voltage ΔV.

[0056] By performing the above process by the magnetic field calculation unit 4, a measurement signal from which 1 / f noise has been appropriately removed is obtained. This measurement signal is amplified by the amplifier 5 and converted into a digital signal by the A / D conversion circuit 6. In this way, the measurement signal obtained by the magnetic measurement method using the magnetic sensor 1 according to this embodiment has 1 / f noise appropriately removed, so that the resolution (magnetic resolution) of the signal based on the measured magnetic field H is higher than that of the signal based on the first output and the signal based on the second output.

[0057] (Modification) FIG. 7 is an explanatory diagram of a modified example of the variable magnetic field detector included in the magnetic sensor according to the first embodiment of the present invention, and the Hall element is in the second state. The variable magnetic field detector 2 shown in FIG. 7 is different from the variable magnetic field detector 2 shown in FIG. 2 in that the magnetic field controller 20 does not have a laminated structure of the spin torque generator 21 and the anisotropy variable part 22, but has these functions integrated, that is, includes an electromagnetic field controller 201 that generates a magnetic field 201m having a component in the X direction (insensitive direction) by energization. Specifically, the electromagnetic field controller 201 generates a spin current 201s in the Z1 direction by passing a current 201c in the Y1 direction, and the magnetic field 201m in the X1 direction is generated in the electromagnetic field controller 201 based on this spin current 201s. Since the electromagnetic field controller 201 and the Hall element 10 are magnetically coupled, the Hall element 10 is in the second state due to the magnetic field 201m in the X1 direction generated in the electromagnetic field controller 201, and a magnetic field 10m in the X1 direction is generated.

[0058] 7 shows a no-magnetic-field state, the magnetic field 10m generated in the Hall element 10 in the second state is substantially parallel to the magnetic field 201m generated in the electromagnetic field control unit 201. Even if the measurement magnetic field H in the Z1 direction is applied in this state, the magnetic field 10m of the Hall element 10 is unlikely to have a component in the Z1 direction, and the Hall voltage generated in the Hall element 10 is low.

[0059] Second embodiment Fig. 8 is a diagram for explaining an example (no magnetic field state) of a variable magnetic field detection unit included in the magnetic sensor according to the second embodiment of the present invention. Fig. 9 is a diagram for explaining a first example (Hall element in a first state) of a variable magnetic field detection unit included in the magnetic sensor according to the second embodiment of the present invention. Fig. 10A is a diagram for explaining a first example (Hall element in a second state) of a variable magnetic field detection unit included in the magnetic sensor according to the second embodiment of the present invention. Fig. 10B is an XY plan view for explaining the Lorentz force acting on the current flowing through the Hall element shown in Fig. 10A.

[0060] 8, the variable magnetic field detection unit 2 included in the magnetic sensor 1 according to the second embodiment has a basic structure (a structure in which a Hall element 10, a magnetic field control unit 20 having a spin torque generation unit 21 and an anisotropy variable unit 22, and a permanent magnet layer 30 are stacked) in common with the variable magnetic field detection unit 2 according to the first embodiment, but the direction of the magnetic field based on the anomalous Hall effect in the Hall element 10 is different and is the X direction. That is, the magnetic sensing direction in which the Hall element 10 exhibits the anomalous Hall effect is along the Z direction in the first embodiment, but is along the X direction in the second embodiment.

[0061] Based on this difference, the direction of the measurement magnetic field H, the arrangement of the electrodes of the first circuit 60, the magnetization direction of the permanent magnet layer 30, and the direction of the magnetic field 20m generated in the anisotropy variable unit 22 are different. In a first example of the second embodiment, a magnetic field 20m along the Y direction is generated in the anisotropy variable unit 22 by the spin orbit torque from the spin torque generation unit 21 (see FIG. 10A). That is, in this example, the magnetically sensitive direction and the insensitive direction are both perpendicular to the stacking direction (Z direction) of the Hall element 10 and the magnetic field control unit 20, and specifically, the magnetically sensitive direction is along the X direction and the insensitive direction is along the Y direction.

[0062] In the variable magnetic field detector 2 according to the second embodiment, as shown in Fig. 8, the electrodes of the first circuit 60 are provided at the ends of the stacking direction (Z direction) of the laminate in which the Hall element 10, the magnetic field controller 20, and the permanent magnet layer 30 are stacked. Therefore, in the Hall element 10, the current 10c from the power supply Vb of the first circuit 60 is oriented in the Z2 direction. Furthermore, the magnetization 30m of the permanent magnet layer 30 is oriented in the Z direction. Therefore, in a magnetic field-free state, a magnetic field 10m along the Z1 direction is generated in the Hall element 10 under the influence of the magnetization 30m of the permanent magnet layer 30.

[0063] (First state) 9, when the spin torque generation unit 21 is in a first state where it is not energized, a measurement magnetic field H is applied in the X1 direction, and the Hall element 10 receives the measurement magnetic field H, and an anomalous Hall effect is generated in the Hall element 10. As a result, a magnetic field 10m having a large component in the X1 direction along the magnetic sensing direction is generated in the Hall element 10, and the Hall element 10 exhibits the anomalous Hall effect. This magnetic field 10m causes a Lorentz force F in the Y1 direction to act on the charge (electrons) of the current 10c, and a Hall voltage is generated in the Y direction. This Hall voltage is measured by the second circuit 61, and a first output is obtained.

[0064] In addition, since the magnetization 30m of the permanent magnet layer 30 acts on the Hall element 10 even in the first state, the magnetic field 10m generated in the Hall element 10 may have a component in the Z1 direction due to the influence of the magnetization 30m. Even in this case, the direction of the magnetization 30m (Z direction) is parallel to the direction of the current 10c and is one of the insensitive directions, so no Hall voltage is generated based on the magnetization 30m. In other words, the magnetization 30m of the permanent magnet layer 30 does not affect the measurement value of the measured magnetic field H included in the first output.

[0065] (Second state) As shown in FIG. 10A, in the second state, in this embodiment, the current 20c from the second circuit 61 having the measurement power supply Vm is in the Y1 direction. This current 20c generates a spin current 20s in the Z1 direction in the spin torque generating unit 21, and the spin orbit torque generated by this spin current 20s generates a magnetic field 20m in the Y2 direction along the insensitive direction in the anisotropy variable unit 22. Influenced by the magnetic field 20m generated in the anisotropy variable unit 22, the magnetic field 10m generated in the Hall element 10 magnetically coupled to the anisotropy variable unit 22 has a component in the Y2 direction along the magnetic field 20m that is larger than the component in the X1 direction along the measurement magnetic field H. That is, a strong magnetic field along the Y direction (insensitive direction) is generated in the Hall element 10. As a result, even if the Hall element 10 receives the measurement magnetic field H along the X direction (magnetic sensing direction), it does not show the anomalous Hall effect, and the sensitivity of the measurement magnetic field H decreases. 10B, in the second state, the Lorentz force F acting on the current 10c flowing through the Hall element 10 has a larger component in the X1 direction than in the Y1 direction. As a result, the Hall voltage measured in the second circuit 61 becomes smaller, and a signal including this measurement result is output from the variable magnetic field detection unit 2 as the second output.

[0066] (Another example of the second embodiment) 11 is a diagram illustrating a second example of the variable magnetic field detector (Hall element in a second state) included in the magnetic sensor according to the second embodiment of the present invention. The variable magnetic field detector 2 according to this example differs from the variable magnetic field detector 2 according to the first example of the second embodiment in that the direction of the magnetic field 20m generated in the anisotropy variable part 22 by the spin orbit torque from the spin torque generation part 21 is along the Z direction. That is, in the second example of the second embodiment, the magnetic sensing direction is along the X direction, which is one of the directions perpendicular to the element stacking direction (Z direction), and the insensitive direction is along the Z direction along the element stacking direction.

[0067] Therefore, in this example, in the second state in which the current 20c in the Y1 direction flows through the spin torque generating unit 21 by energization from the second circuit 61 having the measurement power supply Vm, a magnetic field 20m in the Z1 direction is generated in the anisotropy variable unit 22. Influenced by the magnetic field 20m generated in the anisotropy variable unit 22, the magnetic field 10m generated in the Hall element 10 magnetically coupled to the anisotropy variable unit 22 has a component in the Z1 direction along the magnetic field 20m generated in the anisotropy variable unit 22 that is larger than the component in the X1 direction along the measurement magnetic field H. That is, a strong magnetic field is generated in the Hall element 10 along the Z direction (insensitive direction). As a result, even if the Hall element 10 receives the measurement magnetic field H along the X direction (magnetic sensing direction), it does not exhibit the anomalous Hall effect, and the sensitivity of the measurement magnetic field H decreases. Specifically, as can be understood by comparing FIG. 9 with FIG. 11, in the second state, the Lorentz force F acting on the current 10c flowing through the Hall element 10 is smaller than that in the first state. As a result, the Hall voltage measured in the second circuit 61 becomes smaller, and a signal including this measurement result is output from the variable magnetic field sensing unit 2 as the second output.

[0068] In addition, the magnetization 30m of the permanent magnet layer 30 acts on the Hall element 10 even in the second state, but since the direction of the magnetization 30m (Z1 direction) is the same as the direction of the magnetic field 20m of the anisotropy variable section 22, the magnetization 30m, together with the magnetic field 20m, contributes to the magnetic field 10m having a component in the Z direction (insensitive direction).

[0069] The above-described embodiments are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above-described embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. For example, in the above description, the magnetic field control unit 20 controls the magnetic field 10m of the Hall element 10 by the spin orbit torque, but is not limited to this, and the magnetic field 10m of the Hall element 10 may be controlled by the spin transfer torque, or both the spin orbit torque and the spin transfer torque may contribute to the control of the magnetic field 10m of the Hall element 10. In particular, when the magnetic field control unit 20 includes the electromagnetic field control unit 201, it may be preferable to control the magnetic field 10m of the Hall element 10 by both the spin orbit torque and the spin transfer torque.

[0070] In the case where the magnetic field control unit 20 has a spin torque generating unit 21 that generates a spin orbit torque by energization, the detailed structure of the variable magnetic field detection unit 2 is not limited as long as the Hall element 10 can generate a magnetic field having a component in the insensitive direction by receiving the spin orbit torque from the spin torque generating unit 21. For example, the Hall element 10 and the anisotropy variable unit 22 may be integrated in the variable magnetic field detection unit 2. FIG. 12 is a diagram for explaining the variable magnetic field detection unit (no magnetic field state) included in the magnetic sensor according to the modification of the first embodiment of the present invention, FIG. 13 is a diagram for explaining the variable magnetic field detection unit (anisotropy variable Hall element in a first state) included in the magnetic sensor according to the modification of the first embodiment of the present invention, and FIG. 14 is a diagram for explaining the variable magnetic field detection unit (anisotropy variable Hall element in a second state) included in the magnetic sensor according to the modification of the first embodiment of the present invention.

[0071] As shown in FIG. 12, the variable magnetic field detection unit 2 according to this modification includes an anisotropy variable Hall element 11 in which a Hall element 10 and an anisotropy variable unit 22 are integrated. The anisotropy variable Hall element 11 is a Hall element that receives a spin orbit torque from a spin torque generation unit 21 and generates a magnetic field having a component in an insensitive direction. At this time, the magnetic field control unit 20 is composed of the spin torque generation unit 21. In the magnetic field-free state shown in FIG. 12, the direction of the magnetic field 11m generated in the anisotropy variable Hall element 11 is along the direction (X1 direction) of the magnetization 30m of the permanent magnet layer 30. The direction (X direction) of this magnetic field 11m is one of the insensitive directions and is parallel to the direction of the current 11c flowing through the anisotropy variable Hall element 11 by the supply power source Vb of the first circuit 60, so that the Lorentz force does not act on the charge (electrons) of the current 11c, and no Hall voltage is generated based on the magnetic field 11m.

[0072] The first state shown in Figure 13 is a state in which the direction of the magnetic field 11m generated in the anisotropic variable Hall element 11 is not controlled by the spin torque generation unit 21, and the variable magnetic field detection unit 2 outputs a first output including the measurement result when measuring the measurement magnetic field H along the Z direction (magnetic sensing direction) in the first state.

[0073] 14, the current 20c in the Y1 direction from the second circuit 61 generates a spin current 20s in the spin torque generating unit 21, and the spin orbit torque generated by this spin current 20s causes a magnetic field 11m generated in the anisotropy variable Hall element 11 to have a strong component in the X1 direction. That is, a strong magnetic field along the X direction (insensitive direction) is generated in the anisotropy variable Hall element 11. As a result, even when the anisotropy variable Hall element 11 receives a measurement magnetic field H along the Z direction (magnetic sensing direction), it does not clearly exhibit the anomalous Hall effect, and the sensitivity of the measurement magnetic field H decreases.

[0074] The material constituting the anisotropy variable Hall element 11 is not particularly limited as long as it is a conductive material that generates a strong magnetic field along an insensitive direction such as the X direction based on the spin current 20s from the spin torque generation unit 21. An example of the material is a conductive antiferromagnetic material such as Mn3X (X=Sn, Ge, Ga, Rh, Pt, Ir).

[0075] When the Hall element 10 and the magnetic field control unit 20 are electrically connected and the circuit that supplies current to the magnetic field control unit 20 and the circuit that measures the Hall voltage generated in the Hall element 10 are at least partially common (a specific example is the case where the second circuit 61 shown in FIG. 4 serves both as the circuit that supplies current to the magnetic field control unit 20 and the circuit that measures the Hall voltage generated in the Hall element 10), the method of measuring the measured magnetic field H performed by the magnetic field calculation unit 4 is not limited to the example shown in FIG. 6.

[0076] As another example of such a measurement method, the magnetic field calculation unit 4 may obtain the Hall voltage of the Hall element 10 by an adjusted output obtained by removing a signal corresponding to the control voltage from an output including a measurement result when the variable magnetic field detection unit 2 measures the measured magnetic field H in a state in which a control voltage is applied to the magnetic field control unit 20 to control the direction of the magnetic field generated in the Hall element 10.

[0077] Specifically, in the configuration shown in FIG. 4, when the measurement magnetic field H is constant (DC) during the measurement time, if the control voltage applied from the measurement power source Vm to the magnetic field control unit 20 is an AC signal with a predetermined frequency f, the magnetic field 20m generated in the anisotropy variable unit 22 also oscillates with the frequency f. As a result, the magnetic field 10m generated in the Hall element 10 also oscillates with the frequency f, and the Hall voltage becomes a signal in which a DC component based on the measurement magnetic field H and an AC component based on the control voltage are superimposed. This superimposed signal is measured by the measurement power source Vm, output as a measurement signal from the variable magnetic field detection unit 2, and reaches the magnetic field calculation unit 4. The magnetic field calculation unit 4 subtracts the AC component corresponding to the control voltage from this measurement signal to obtain a signal including the intensity of the measurement magnetic field H. This allows the noise components included in the control voltage applied to the magnetic field control unit 20 to be appropriately removed from the measurement signal.

[0078] Fig. 15 is a diagram for explaining an example of a case where a magnetic field based on exchange coupling involving an antiferromagnetic material is used as a bias magnetic field source for controlling the direction of the magnetic field generated in the Hall element in a magnetic field-free state. In the example shown in Fig. 2, the permanent magnet layer 30, which is the bias magnetic field source, is laminated on the Hall element 10, but in the example shown in Fig. 15, the bias magnetic field source has a structure that gives a magnetic field based on exchange coupling. Specifically, the part of the anisotropy variable part 22 that contacts the Hall element 10 is made of an antiferromagnetic material, and this part generates an exchange coupling 22ex with the Hall element 10, causing the Hall element 10 to generate a magnetic field 10m based on exchange coupling.

[0079] Fig. 16 is a diagram for explaining another example of a case where a magnetic field based on exchange coupling involving an antiferromagnetic material is used as a bias magnetic field source for controlling the direction of the magnetic field generated in the Hall element in a magnetic field-free state. In the example shown in Fig. 15, the magnetic field control unit 20 has an anisotropy variable unit 22, and the part of the anisotropy variable unit 22 that contacts the Hall element 10 is made of an antiferromagnetic material, but in the example shown in Fig. 16, like the structure shown in Fig. 7, the magnetic field control unit 20 has an electromagnetic field control unit 201, and the part of the electromagnetic field control unit 201 that contacts the Hall element 10 is made of an antiferromagnetic material, and this part generates an exchange coupling 201ex with the Hall element 10, causing the Hall element 10 to generate a magnetic field 10m based on exchange coupling.

[0080] Fig. 17 is a diagram for explaining another example of a case where a magnetic field based on exchange coupling involving an antiferromagnetic material is used as a bias magnetic field source for controlling the direction of the magnetic field generated in the Hall element in a magnetic field-free state. In the example shown in Fig. 15, the magnetic field control unit 20 has an anisotropy variable unit 22, and the part of the anisotropy variable unit 22 that contacts the Hall element 10 is made of an antiferromagnetic material, but in the example shown in Fig. 17, the variable magnetic field detection unit 2 has an anisotropy variable Hall element 11 similar to the structure shown in Fig. 12, and the magnetic field control unit 20 is composed of a spin torque generation unit 21. And, the part of the spin torque generation unit 21 that contacts the anisotropy variable Hall element 11 is made of an antiferromagnetic material, and this part generates an exchange coupling 21ex with the anisotropy variable Hall element 11, causing the anisotropy variable Hall element 11 to generate a magnetic field 11m based on exchange coupling.

[0081] In addition, in the example shown in FIG. 2, the permanent magnet layer 30, which is the bias magnetic field source, is stacked on the Hall element 10, but the bias magnetic field source may not be stacked on the Hall element 10 and may be located in an in-plane direction, for example, in the XY plane direction.

[0082] The present invention includes the following aspects. (1) A magnetic sensor comprising a variable magnetic field detection unit having a Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect, and a magnetic field control unit that controls the Hall element so that a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction is generated in the Hall element. (2) The magnetic sensor described in (1) above further includes a magnetic field calculation unit that calculates the measured magnetic field based on a first output including a measurement result when the variable magnetic field detection unit measures a measured magnetic field along the magnetic sensing direction in a first state in which the direction of the magnetic field generated in the Hall element is not controlled by the magnetic field control unit, and a second output including a measurement result when the variable magnetic field detection unit measures the measured magnetic field in a second state in which the direction of the magnetic field generated in the Hall element is controlled by the magnetic field control unit. (3) The magnetic sensor according to (2) above, wherein the magnetic field control unit generates a spin orbit torque when energized, and the Hall element generates a magnetic field having a component in the insensitive direction based on the spin orbit torque. (4) The magnetic sensor according to (2) above, wherein the Hall element and the magnetic field control unit are electrically connected, and a circuit for passing current through the magnetic field control unit and a circuit for measuring the Hall voltage generated in the Hall element are at least partially common to each other. (5) The magnetic sensor described in (2) above, wherein the magnetic field calculation unit performs processing including subtracting from the first output a second adjusted output obtained by removing from the second output a signal corresponding to a voltage applied to the magnetic field control unit to control the Hall element, to obtain a signal indicating the measured magnetic field. (6) The magnetic sensor according to (2) above, wherein the Hall element and the magnetic field control unit are magnetically coupled. (7) The magnetic sensor described in (1) above, further comprising a bias magnetic field source that generates a bias magnetic field that sets the magnetic field generated in the Hall element in a direction that intersects with the magnetic sensing direction in a magnetic field-free state in which no measurement magnetic field is applied. (8) The magnetic sensor according to (4) above, wherein the Hall element and the magnetic field control unit form a laminated structure. (9) The magnetic sensor described in (8) above, wherein the magnetic field control unit is formed by stacking a spin torque generation unit that generates a spin orbit torque when current is applied and an anisotropy variable unit that generates a magnetic field having a component in the insensitive direction based on the spin orbit torque from the spin torque generation unit, and the anisotropy variable unit is magnetically coupled to the Hall element. (10) The magnetic sensor described in (8) above, wherein the magnetic field control unit has an electromagnetic field control unit that generates a magnetic field having a component in the insensitive direction when current is passed through it, and the electromagnetic field control unit is magnetically coupled to the Hall element. (11) The magnetic sensor according to (8) above, wherein the magnetic sensing direction is along a stacking direction of the Hall element and the magnetic field control unit. (12) The magnetic sensor according to (8) above, wherein the magnetic sensing direction and the insensitive direction are both perpendicular to a stacking direction of the Hall element and the magnetic field control unit. (13) The magnetic sensor according to (8) above, wherein the insensitive direction is along a stacking direction of the Hall element and the magnetic field control unit. (14) The magnetic sensor described in (2) above, wherein the magnetic field control unit has a spin torque generation unit that generates a spin orbit torque when current is applied, and the Hall element is an anisotropy variable Hall element that receives the spin orbit torque from the spin torque generation unit and generates a magnetic field having a component in the insensitive direction. (15) The magnetic sensor according to (7) above, wherein the bias magnetic field includes a magnetic field generated by a permanent magnet or an induced magnetic field generated by energizing a coil. (16) The magnetic sensor according to (7) above, wherein the bias magnetic field source has a portion made of an antiferromagnetic material and is magnetically coupled to the Hall element, and the bias magnetic field is based on exchange coupling involving the antiferromagnetic material. (17) The magnetic sensor according to (16), wherein the magnetic field control section has a portion made of the antiferromagnetic material. (18) The magnetic sensor described in (17) above, wherein the magnetic field control unit is formed by stacking a spin torque generation unit that generates a spin orbit torque when current is applied, and an anisotropy variable unit that generates a magnetic field having a component in the insensitive direction based on the spin orbit torque from the spin torque generation unit, and the anisotropy variable unit has a portion made of the antiferromagnetic material and is magnetically coupled to the Hall element. (19) The magnetic sensor described in (17) above, wherein the magnetic field control unit has an electromagnetic field control unit that generates a magnetic field having a component in the insensitive direction when current is passed through it, the electromagnetic field control unit having a portion made of the antiferromagnetic material and magnetically coupled to the Hall element. (20) The magnetic sensor described in (17) above, wherein the magnetic field control unit has a spin torque generation unit that generates a spin orbit torque when current is applied, the Hall element is an anisotropy variable Hall element that receives the spin orbit torque from the spin torque generation unit and generates a magnetic field having a component in the insensitive direction, and the spin torque generation unit has a portion made of the antiferromagnetic material and is magnetically coupled to the anisotropy variable Hall element. (21) A magnetic measurement method using a magnetic sensor including a variable magnetic field detection unit that measures a measured magnetic field and a magnetic field calculation unit that calculates the measured magnetic field based on an output from the variable magnetic field detection unit, wherein the variable magnetic field detection unit includes a Hall element having a magnetic sensitivity direction that exhibits an anomalous Hall effect, and a magnetic field control unit that controls the Hall element so that a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensitivity direction is generated in the Hall element, the magnetic measurement method comprising: a first measurement step of obtaining a first output from the variable magnetic field detection unit including a measurement result in a first state in which the direction of the magnetic field generated in the Hall element is not controlled by the magnetic field control unit; a second measurement step of obtaining a second output from the variable magnetic field detection unit including a measurement result in a second state in which the direction of the magnetic field generated in the Hall element is controlled by the magnetic field control unit; and a magnetic field calculation step of calculating the measured magnetic field from the first output and the second output in the magnetic field calculation unit. [Industrial Applicability]

[0083] The present invention is useful as a magnetic sensor and a magnetic measurement method having high magnetic resolution, which are capable of detecting an external magnetic field with high sensitivity. [Explanation of symbols]

[0084] 1: Magnetic sensor 2: Variable magnetic field detection unit 3: Control power supply 4: Magnetic field calculation section 5: Amplifier 6: A / D conversion circuit 7: Control section 10: Hall element 11: Anisotropic variable Hall element 10c, 11c, 20c, 201c: Current 10m, 11m, 20m, 201m: magnetic field 20: Magnetic field control section 20s, 201s: spin current 21: Spin torque generating unit 22: Anisotropic variable section 21ex, 201ex, 22ex: Exchange coupling 30: Permanent magnet layer 30m: magnetized 60:1st circuit 61: 2nd circuit 201: Electromagnetic field control section F: Lorentz force H: Measurement magnetic field V1, V2, Vs, ΔV: Voltage Vb: Supply power Vm: power supply for measurement

Claims

1. a Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect; a magnetic field control unit for controlling a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction generated in the Hall element; A variable magnetic field detection unit having a the magnetic field control unit has a spin torque generation unit that generates a spin orbit torque by energization, The magnetic sensor according to claim 1, wherein the Hall element is an anisotropy variable Hall element that receives the spin orbit torque from the spin torque generation unit and generates a magnetic field having a component in the insensitive direction.

2. The magnetic sensor according to claim 1 , wherein the spin torque generating portion has a portion made of an antiferromagnetic material and is magnetically coupled to the anisotropy variable Hall element.

3. a Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect; a magnetic field control unit for controlling a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction generated in the Hall element; A variable magnetic field detection unit having a The magnetic field control unit has an electromagnetic field control unit that generates a magnetic field having a component in the insensitive direction by energization, The magnetic field control unit generates a spin orbit torque when a current is applied, and the Hall element generates a magnetic field having a component in the insensitive direction based on the spin orbit torque.

4. a first output including a measurement result when the variable magnetic field detection unit measures a measurement magnetic field along the magnetic sensing direction in a first state in which the direction of the magnetic field generated in the Hall element is not controlled by the magnetic field control unit; a second output including a measurement result when the variable magnetic field detection unit measures the measurement magnetic field in a second state in which the direction of the magnetic field generated in the Hall element is controlled by the magnetic field control unit; and The magnetic sensor according to claim 1 , further comprising a magnetic field calculation unit that calculates the measured magnetic field based on a.

5. the Hall element and the magnetic field control unit are electrically connected to each other; The magnetic sensor according to claim 4 , wherein a circuit for energizing the magnetic field control section and a circuit for measuring a Hall voltage generated in the Hall element are at least partially common to each other.

6. The magnetic sensor of claim 4, wherein the magnetic field calculation unit performs processing that includes subtracting from the first output a second adjusted output obtained by removing from the second output a signal corresponding to a voltage applied to the magnetic field control unit to control the Hall element, to obtain a signal indicating the measured magnetic field.

7. The magnetic sensor according to claim 3 , wherein the Hall element and the magnetic field control unit are magnetically coupled to each other.

8. A Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect; a magnetic field control unit for controlling a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction generated in the Hall element; A variable magnetic field detection unit having a The magnetic field control unit has an electromagnetic field control unit that generates a magnetic field having a component in the insensitive direction by energization, A magnetic sensor comprising: a bias magnetic field source that generates a bias magnetic field that sets the magnetic field generated in the Hall element in a direction that intersects with the magnetic sensing direction in a magnetic field-free state where a measurement magnetic field is not applied.

9. The magnetic sensor according to claim 8 , wherein the bias magnetic field includes a magnetic field generated by a permanent magnet or an induced magnetic field generated by energizing a coil.

10. 9. The magnetic sensor according to claim 8, wherein the bias magnetic field source has a portion made of an antiferromagnetic material and is magnetically coupled to the Hall element, and the bias magnetic field is based on exchange coupling involving the antiferromagnetic material.

11. A Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect; a magnetic field control unit for controlling a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction generated in the Hall element; A variable magnetic field detection unit having a The magnetic field control unit has an electromagnetic field control unit that generates a magnetic field having a component in the insensitive direction by energization, A magnetic sensor characterized in that the magnetic field control section has a portion made of an antiferromagnetic material.

12. A Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect; a magnetic field control unit for controlling a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction generated in the Hall element; A variable magnetic field detection unit having a The magnetic field control unit has an electromagnetic field control unit that generates a magnetic field having a component in the insensitive direction by energization, The magnetic sensor is characterized in that the electromagnetic field control section has a portion made of an antiferromagnetic material and is magnetically coupled to the Hall element.

13. 4. The magnetic sensor according to claim 1, wherein the Hall element has a portion made of an antiferromagnetic material.

14. A magnetic sensor as described in claim 1 or claim 3, comprising a bias magnetic field source that generates a bias magnetic field that sets the magnetic field generated in the Hall element in a direction that intersects the magnetic sensing direction in a magnetic field-free state where a measurement magnetic field is not applied.

15. A magnetic sensor as described in claim 1 or claim 3, wherein the magnetic field control unit has a portion made of an antiferromagnetic material.

16. A magnetic sensor as described in claim 3, wherein the electromagnetic field control unit has a portion made of an antiferromagnetic material and is magnetically coupled to the Hall element.

17. A magnetic sensor as described in any one of claims 8, 11 and 12, wherein the magnetic field control unit generates a spin orbit torque when current is passed through it, and the Hall element generates a magnetic field having a component in the insensitive direction based on the spin orbit torque.

18. A magnetic measurement method using a magnetic sensor including a variable magnetic field detection unit that measures a measurement magnetic field, and a magnetic field calculation unit that calculates the measurement magnetic field based on an output from the variable magnetic field detection unit, The variable magnetic field detection unit is a Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect; a magnetic field control unit for controlling a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction generated in the Hall element, the magnetic field control unit has a spin torque generation unit that generates a spin orbit torque by energization, and the Hall element is an anisotropy variable Hall element that receives the spin orbit torque from the spin torque generation unit and generates a magnetic field having a component in the insensitive direction, a first measurement step of obtaining a first output from the variable magnetic field detection unit, the first output including a measurement result in a first state in which a direction of a magnetic field generated in the Hall element is not controlled by the magnetic field control unit; a second measurement step of obtaining, from the variable magnetic field detection unit, a second output including a measurement result in a second state in which a direction of a magnetic field generated in the Hall element is controlled by the magnetic field control unit; a magnetic field calculation step of calculating the measured magnetic field from the first output and the second output in the magnetic field calculation unit; A magnetic measurement method comprising:

19. A magnetic measurement method using a magnetic sensor including a variable magnetic field detection unit that measures a measurement magnetic field, and a magnetic field calculation unit that calculates the measurement magnetic field based on an output from the variable magnetic field detection unit, The variable magnetic field detection unit is a Hall element having a magnetic sensing direction that exhibits an anomalous Hall effect; a magnetic field control unit for controlling a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensing direction generated in the Hall element, the magnetic field control unit has an electromagnetic field control unit that generates a magnetic field having a component in the insensitive direction by energization, a first measurement step of obtaining a first output from the variable magnetic field detection unit, the first output including a measurement result in a first state in which a direction of a magnetic field generated in the Hall element is not controlled by the magnetic field control unit; a second measurement step of obtaining, from the variable magnetic field detection unit, a second output including a measurement result in a second state in which a direction of a magnetic field generated in the Hall element is controlled by the magnetic field control unit; a magnetic field calculation step of calculating the measured magnetic field from the first output and the second output in the magnetic field calculation unit; A magnetic measurement method comprising:

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