Magnetic sensor and magnetic measurement method

Abstract

To provide a magnetic sensor and magnetic measurement method capable of measuring a small magnetic field with high accuracy by removing 1 / f noise.SOLUTION: A magnetic sensor comprises a variable magnetic field detection unit including a Hall element having a magnetically sensitive direction representing an anomalous Hall effect, and a magnetic field control unit for controlling the Hall element so that a magnetic field having a component in an insensitive direction perpendicular to the magnetically sensitive direction is generated in the Hall element. The magnetic sensor may further include a magnetic field calculation unit for calculating a measurement magnetic field on the basis of a first output including a measurement result when the variable magnetic field detection unit measures the measurement magnetic field along the magnetically sensitive direction in a first state where 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 measurement magnetic field in a second state where the direction of the magnetic field generated in the Hall element is controlled by the magnetic field control unit.SELECTED DRAWING: Figure 1

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 include those equipped with magnetoresistive elements that utilize the GMR (giant magnetoresistance) effect or the TMR (tunneling magnetoresistance) effect. The magnetoresistive elements in these magnetic sensors are configured with a fixed magnetic layer, a non-magnetic intermediate layer, and a free magnetic layer stacked in this order. When an external magnetic field to be measured is applied to the magnetoresistive element, the magnetization direction of the free magnetic layer changes, causing a resistance change 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 magnetoresistive element can detect a magnetic field using the resistance change of the magnetoresistive element.

[0003] Magnetic sensors equipped with magnetoresistive elements have 1 / f noise that cannot be removed by filters. 1 / f noise is inversely proportional to frequency, becoming 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 take the 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] Japanese Patent Application Publication No. 2018-115972 [Patent Document 2] Japanese Patent Publication No. 2020-148727 [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 magnetoresistive 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 magnetoresistive element and a magnetic measurement method that can remove 1 / f noise using a configuration different from conventional ones and measure small magnetic fields with high accuracy. [Means for solving the problem]

[0010] In one aspect, the present invention provides a magnetic sensor characterized by comprising a variable magnetic field detection unit having a Hall element having a magnetically sensitive 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 magnetically sensitive direction is generated in the Hall element.

[0011] Magnetic sensors using Hall elements have been able to 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 by using these materials as the constituent materials of Hall elements, it is expected that the magnetic detection sensitivity of magnetic sensors using Hall elements will be further improved. By adding a magnetic field control unit to magnetic sensors with Hall elements that have improved magnetic detection sensitivity, it becomes possible to apply noise reduction measures such as interphase double sampling (CDS). This can particularly improve the magnetic resolution of magnetic sensors.

[0012] In order to realize 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 of the variable magnetic field detection unit measuring the 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 of the variable magnetic field detection unit measuring 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 an insensitive direction perpendicular to the magnetic sensing direction, preferably along the insensitive 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, and therefore 1 / f noise can be removed by CDS using the first and second outputs.

[0013] In the magnetic sensor, the magnetic field control unit may generate a spin orbit torque when energized, 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 to each other, thereby enabling the magnetic sensor to be miniaturized.

[0015] In the above magnetic sensor, the magnetic field calculation unit may perform 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 indicative of the measured magnetic field.

[0016] In the magnetic sensor, the Hall element and the magnetic field control unit may be magnetically coupled, thereby enabling the magnetic field control unit to 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 that intersects with the magnetic sensing direction when no magnetic field is applied to be measured, 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 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-described 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 when current is applied, and the electromagnetic field control unit may be magnetically coupled to the Hall element. The relationship between the stacking direction (element stacking direction) of the Hall element and the magnetic field control unit and the magnetically sensitive direction and the insensitive direction may be appropriately set. Either the magnetically sensitive direction or the insensitive direction may be aligned with the element stacking direction, or both the magnetically sensitive direction and the insensitive direction may be perpendicular to the element stacking direction.

[0020] In another aspect, the present invention provides a magnetic measurement method using a magnetic sensor including a variable magnetic field detector that measures a magnetic field to be measured and a magnetic field calculator that calculates the measured magnetic field based on an output from the variable magnetic field detector. The variable magnetic field detector includes a Hall element having a magnetic sensitivity direction that exhibits an anomalous Hall effect, and a magnetic field controller that controls the Hall element so that the Hall element generates a magnetic field having a component in an insensitive direction perpendicular to the magnetic sensitivity direction. The magnetic measurement method includes a first measurement step of obtaining a first output from the variable magnetic field detector, 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 controller, a second measurement step of obtaining a second output from the variable magnetic field detector, 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 controller, and a magnetic field calculation step of calculating the measured magnetic field from the first output and the second output in the magnetic field calculator. [Effects of the Invention]

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

[0022] [Figure 1] 1 is a block diagram of a magnetic sensor according to an embodiment of the present invention; [Figure 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. [Figure 3] 2 is a diagram 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. FIG. [Figure 4] 3A and 3B 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. [Figure 5] 3 is a flowchart illustrating a magnetic measurement method using the magnetic sensor according to the first embodiment of the present invention. [Figure 6] 3 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 and 5B 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] 10A and 10B are diagrams 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. [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] 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 in a second state). FIG. [Figure 10B] 10B is an XY plan view illustrating the Lorentz force acting on the current flowing through the Hall element shown in FIG. 10A. FIG. [Figure 11] 10 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 (the Hall element is in a second state). FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In each drawing, the same components are designated by the same reference numerals, and their description will be omitted. Reference coordinates are indicated in each drawing as appropriate to indicate the positional relationship of each component.

[0024] Fig. 1 is a block diagram of a magnetic sensor according to one 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 one 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-to-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 as will be described later, includes a Hall element 10 that exhibits the anomalous Hall effect and a magnetic field control unit 20 that controls a magnetic field 10m generated by the Hall element 10. The control power supply 3 applies a predetermined current or 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 with, for example, 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 (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, by calculating the difference between a signal based on the first output and a signal based on the second output, 1 / f noise can be removed from the first output.

[0027] In the magnetic sensor 1, the magnetic field calculation unit 4 calculates the measured magnetic field H, and then 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 illustrating 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 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. Fig. 4 is a diagram 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.

[0029] The variable magnetic field detection unit 2 of the magnetic sensor 1 according to this embodiment includes a Hall element 10 having a magnetically sensitive 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 in an insensitive direction perpendicular to the magnetically sensitive direction is generated in the Hall element 10. In this embodiment, the magnetically sensitive direction of the Hall element 10 is along the Z direction, which is 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 the two directions (X direction and Y direction) perpendicular to the magnetically sensitive direction. In this embodiment, a specific example is taken in which the insensitive direction is along the X direction, which is one of the directions perpendicular to the element stacking direction.

[0030] The material of the Hall element 10 is not limited as long as it can generate the 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. In the former case (magnetization), a ferromagnetic material is exemplified as a material constituting the Hall element 10, and in the latter case (virtual magnetic field), a topological antiferromagnet is exemplified as a material constituting the Hall element 10.

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

[0033] The Hall element 10 is connected to a first circuit 60 provided with 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 when the electric charge is subjected to the Lorentz force F. 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 on both ends of the Hall element 10 in the X direction. Furthermore, since the Hall element 10 and the magnetic field control unit 20 are electrically connected in this embodiment, electrodes related to the second circuit 61 are provided on both ends of a part of the magnetic field control unit 20 (a spin torque generation unit 21 described later) in the Y direction.

[0034] In this embodiment, the magnetic field control unit 20 generates a spin orbit torque when energized, 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 thereby 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] When a current is applied to the spin torque generation unit 21 in the XY plane direction, in this embodiment in the Y direction, the spin Hall effect, the Rashba-Edelstein effect, or the like occurs, and a spin orbit torque is applied to the anisotropy variable unit 22. Materials constituting the spin torque generation unit 21 include heavy metals (5d transition metals) such as Hf, Ta, W, Pt, and Ir, which have high specific gravity among paramagnetic transition metals; topological insulators such as BiSb, BiSe, Bi2Se3, and Bi2Te3; Mn3X (X = Sn, Ge, Ga, Rh, Pt, Ir), and 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 the specific example shown in FIG. 2, the spin torque generation unit 21 is a film-like body, but this film-like body may be composed of a single structure, i.e., a single-layer film, or may be composed of a laminated film. In the case of a laminated film, a boundary region may be formed between adjacent films. The spin torque generation unit 21 may be composed entirely of a single material, or may be composed of multiple materials. When composed of multiple materials, it may have a laminated structure as described above, or it may have a dispersed structure. In the case of a dispersed structure, the degree of dispersion is arbitrary, and it may be a structure in which nanocrystals are dispersed, or a fixed pattern may be formed. In addition, a compositional distribution may be set in the spin torque generation unit 21.

[0037] The anisotropy variable unit 22 can generate a magnetic field 20m having a component in the X direction (the dead direction in this embodiment) based on the spin orbit torque from the spin torque generation unit 21 (see FIG. 4). Furthermore, since the anisotropy variable unit 22 is magnetically coupled to the Hall element 10, when the magnetic field 20m is generated in the anisotropy variable unit 22 based on the spin orbit torque from the spin torque generation unit 21, a magnetic field 10m having a component in the X direction (the dead direction) is also generated in the Hall element 10 (see FIG. 4). Note that in FIG. 2, no spin orbit torque is applied from the spin torque generation unit 21 to the anisotropy variable unit 22, and no measurement magnetic field H is applied, so the magnetic field 20m of the anisotropy variable unit 22 may be oriented 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 MnX (X = Sn, Ge, Ga, Rh, Pt, Ir).

[0039] In one 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, i.e., a single-layer film, or may be composed of a laminated film. In the case of a laminated film, a boundary region may be formed between adjacent films. The anisotropy variable part 22 may be composed entirely of a single material, or may be composed of multiple materials. When composed of multiple materials, it may have a laminated structure as described above, or it may have a dispersed structure. In the case of 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, a permanent magnet layer 30 is laminated on the Hall element 10 as a bias magnetic field source. In a magnetic field-free state where no measurement magnetic field H is applied, as shown in FIG. 2, the direction of the magnetic field 10m generated in the Hall element 10 is aligned with the direction of the magnetization 30m of the permanent magnet layer 30 (X1 direction). The direction of this 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 from the power supply Vb of the first circuit 60. Therefore, no Lorentz force acts on the charge (electrons) of the current 10c, and no Hall voltage is generated based on the magnetic field 10m. Furthermore, the bias magnetic field based on the magnetization 30m of the permanent magnet layer 30 tends to monomagnetize the material constituting the Hall element 10. Therefore, the hysteresis characteristics of the magnetic sensor 1 are likely to be excellent. The bias magnetic field source is not limited to a permanent magnet; it may be a structure that generates an induced magnetic field due to current flow in 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 in the first state, 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).

[0042] In this embodiment, a current 10c from a power supply Vb, which supplies electrons as charges receiving the Lorentz force F, flows through the Hall element 10 in the X2 direction. When the Hall element 10 receives a measurement magnetic field H in the Z direction (magnetic sensing direction), a magnetic field 10m having a large component in the Z direction is generated in the Hall element 10, causing 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 resulting from the Berry curvature present in reciprocal space. Since the intensity of the magnetic field 10m generated in this way is greater than the measurement magnetic field H, the Hall element 10 exhibiting the anomalous Hall effect has the function of amplifying the measurement magnetic field H.

[0043] This magnetic field 10m causes a Lorentz force F in the Y2 direction to act on electrons carrying the current 10c. As described above, the Hall element 10 and the magnetic field control unit 20 are electrically connected, and therefore 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 supply Vm having a voltage measurement function through an electrode provided at the Y-direction end of the magnetic field control unit 20, and a signal including this measurement result is output from the variable magnetic field detection unit 2 as a 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 the 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] Note that, because 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 oriented in the Y1 direction. This current 20c generates a spin current 20s in the spin torque generation 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 greater than a component in the Z1 direction along the measurement magnetic field H. In other words, a strong magnetic field is generated in the Hall element 10 along the X direction (insensitive direction). As a result, the Hall element 10 does not exhibit the anomalous Hall effect even when subjected to the measurement magnetic field H along the Z direction (magnetic sensing direction), and its sensitivity to 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 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] 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 (X direction) is parallel to the direction of the magnetic field 20m of the anisotropy variable part 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 the first embodiment of the present invention. FIG. 6 is a timing chart illustrating a magnetic measurement method using a magnetic sensor according to the 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 no current 20c flows through the magnetic field control unit 20.

[0050] In this way, the Hall element 10 is set to the first state, a current 10c is passed through the Hall element 10 from the supply power supply Vb, and the voltage is measured at the measurement power supply 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, in the second measurement step, 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 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 set to the second state, a current 10c is passed through the Hall element 10 from the supply power supply Vb, and the voltage is measured at the measurement power supply Vm. The measured voltage is equal to the sum of the voltage Vs applied to the magnetic field control unit 20 to pass the current 20c 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 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).

[0053] The measurement times for steps S101 and S102 are both sufficiently shorter than 1 microsecond (for example, 0.01 microseconds), and the time required for steps S101 and S102 is also sufficiently shorter than 1 microsecond (for example, 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 contained in the first output and the 1 / f noise contained in the second output are substantially equal.

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

[0055] The magnetic field calculation unit 4 reads 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 the measured magnetic field H based on a signal based on the first output and a signal based on the second output (step S103), which is a magnetic field calculation step. In this process, not only is the second output subtracted from the first output, but the voltage Vs included in the second output is also removed, resulting in a second adjusted output. The timing chart shown in FIG. 6(c) shows a voltage V1 based on the first output and a voltage V2 based on the second adjusted output. 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 processing 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. As such, the measurement signal obtained by the magnetic measurement method using the magnetic sensor 1 according to this embodiment has 1 / f noise appropriately removed, and therefore 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 or the signal based on the second output.

[0057] (Variation) 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, with the Hall element in the second state. The variable magnetic field detector 2 shown in FIG. 7 differs from the variable magnetic field detector 2 shown in FIG. 2 in that the magnetic field controller 20 does not have a layered structure of the spin torque generator 21 and the anisotropy variable unit 22, but rather integrates these functions. That is, the variable magnetic field controller 201 includes an electromagnetic field controller 201 that generates a magnetic field 201m having a component in the X direction (insensitive direction) when current is applied. Specifically, when a current 201c flows in the Y1 direction, the electromagnetic field controller 201 generates a spin current 201s in the Z1 direction. Based on this spin current 201s, the electromagnetic field controller 201 generates a magnetic field 201m in the X1 direction. Because the electromagnetic field controller 201 and the Hall element 10 are magnetically coupled, the X1-direction magnetic field 201m generated in the electromagnetic field controller 201 causes the Hall element 10 to enter the second state, generating a magnetic field 10m in the X1 direction.

[0058] 7 shows a no-magnetic-field state, the magnetic field 10m generated in the Hall element 10 in the second state is approximately 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 illustrating an example of a variable magnetic field detection unit (no magnetic field state) included in the magnetic sensor according to the second embodiment of the present invention. Fig. 9 is a diagram illustrating a first example of a variable magnetic field detection unit (Hall element in a first state) included in the magnetic sensor according to the second embodiment of the present invention. Fig. 10A is a diagram illustrating a first example of a variable magnetic field detection unit (Hall element in a second state) included in the magnetic sensor according to the second embodiment of the present invention. Fig. 10B is an XY plan view illustrating 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 the same basic structure (a stacked structure of 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) as 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, being 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, there are differences in 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. In the 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. 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 the absence of a magnetic field, a magnetic field 10m along the Z1 direction is generated in the Hall element 10 due to 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 current is not applied, a measurement magnetic field H is applied in the X1 direction, and the Hall element 10 receives the measurement magnetic field H, causing the anomalous Hall effect. As a result, a magnetic field 10m with 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 charges (electrons) of the current 10c, generating a Hall voltage in the Y direction. This Hall voltage is measured by the second circuit 61, and a first output is obtained.

[0064] Note that, because 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 oriented in the Y1 direction. This current 20c generates a spin current 20s oriented in the Z1 direction in the spin torque generation unit 21, and the spin orbit torque generated by this spin current 20s generates a magnetic field 20m oriented in the Y2 direction, which is 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 oriented in the Y2 direction, which is along the magnetic field 20m, that is greater than a component oriented in the X1 direction, which is along the measurement magnetic field H. In other words, a strong magnetic field oriented in the Y direction (insensitive direction) is generated in the Hall element 10. As a result, the Hall element 10 does not exhibit the anomalous Hall effect even when subjected to the measurement magnetic field H oriented in the X direction (magnetic sensing direction), and its sensitivity to the measurement magnetic field H is reduced. 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 the component 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 a variable magnetic field detector (Hall element in a second state) included in a 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 generator 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 a current 20c in the Y1 direction flows through the spin torque generation unit 21 due to 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 larger Z1-direction component along the magnetic field 20m generated in the anisotropy variable unit 22 than an X1-direction component 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 when the Hall element 10 receives a measurement magnetic field H along the X direction (magnetic sensing direction), it does not exhibit the anomalous Hall effect, and its sensitivity to the measurement magnetic field H is reduced. Specifically, as can be seen from a comparison between FIGS. 9 and 11, in the second state, the Lorentz force F acting on the current 10c flowing through the Hall element 10 is smaller than 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 detecting section 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 part 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 provided to facilitate understanding of the present invention and are not intended to limit the present invention. Therefore, the elements disclosed in the above embodiments are intended to encompass all design modifications and equivalents 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 using spin-orbit torque. However, this is not limited to this. The magnetic field 10m of the Hall element 10 may be controlled using spin transfer torque, or both spin-orbit torque and 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 using both spin-orbit torque and spin transfer torque.

[0070] The present invention includes the following aspects. (1) A magnetic sensor characterized by comprising a variable magnetic field detection unit having a Hall element having a magnetically sensitive 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 magnetically sensitive 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 described in (2) above, wherein the Hall element and the magnetic field control unit are electrically connected, and the circuit that energizes the magnetic field control unit and the circuit that measures the Hall voltage generated in the Hall element are at least partially common. (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), wherein the Hall element and the magnetic field control unit are magnetically coupled. (7) A magnetic sensor according to (1) above, comprising a bias magnetic field source 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 no measurement magnetic field is applied. (8) The magnetic sensor according to (4), 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 applied, and the electromagnetic field control unit is magnetically coupled to the Hall element. (11) The magnetic sensor according to (8), 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), wherein the magnetically sensitive direction and the insensitive direction are both perpendicular to the stacking direction of the Hall element and the magnetic field control unit. (13) The magnetic sensor according to (8), 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 (1) above, wherein the Hall element and the magnetic field control unit are electrically connected, and the circuit that supplies current to the magnetic field control unit and the circuit that measures the Hall voltage generated in the Hall element in response to the measured magnetic field are at least partially common, and further includes a magnetic field calculation unit that, when a control voltage is applied to the magnetic field control unit to control the direction of the magnetic field generated in the Hall element, obtains the Hall voltage of the Hall element from an adjusted output obtained by removing a signal corresponding to the control voltage from an output including the measurement result when the variable magnetic field detection unit measures the measured magnetic field, in a state where the control voltage is applied to the magnetic field control unit to control the direction of the magnetic field generated in the Hall element. (15) The magnetic sensor according to (1), wherein the Hall element is a film-like body. (16) The magnetic sensor according to (15), wherein the magnetic sensing direction is along the thickness direction of the film body. (17) The magnetic sensor according to (15) above, wherein the magnetically sensitive direction and the insensitive direction are both perpendicular to the thickness direction of the film body. (18) The magnetic sensor according to (15), wherein the insensitive direction is along the thickness direction of the film body. (19) A magnetic measurement method using a magnetic sensor comprising 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 comprises 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 that includes 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 that includes 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]

[0071] The present invention is useful as a magnetic sensor and a magnetic measurement method having high magnetic resolution, which can detect an external magnetic field with high sensitivity. [Explanation of symbols]

[0072] 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 10c, 20c, 201c: current 10m, 20m, 201m: magnetic field 20: Magnetic field control section 20s, 201s: spin current 21: Spin torque generation unit 22: Anisotropic variable section 30: Permanent magnet layer 30m: magnetized 60:1st circuit 61: 2nd circuit 201: Electromagnetic field control unit F: Rope force H: Determination of magnetic field V1, V2, Vs, ΔV: Voltage Vb: Power supply Vm: Measurement power supply

Claims

1. a Hall element having a magnetic sensitivity direction that exhibits an anomalous Hall effect; 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; A magnetic sensor comprising a variable magnetic field detection unit having a

2. 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

3. 3. The magnetic sensor according to claim 2, 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 Hall element and the magnetic field control unit are electrically connected to each other; 3. The magnetic sensor according to claim 2, wherein a circuit for energizing the magnetic field control unit and a circuit for measuring a Hall voltage generated in the Hall element are at least partially common to each other.

5. 3. The magnetic sensor according to claim 2, 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.

6. The magnetic sensor according to claim 2 , wherein the Hall element and the magnetic field control unit are magnetically coupled.

7. 2. The magnetic sensor according to claim 1, further comprising a bias magnetic field source 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 no measurement magnetic field is applied.

8. The magnetic sensor according to claim 4 , wherein the Hall element and the magnetic field control unit form a laminated structure.

9. The magnetic field control unit is a spin torque generating unit that generates a spin-orbit torque when energized; 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; are stacked, The magnetic sensor according to claim 8 , wherein the anisotropy variable portion is magnetically coupled to the Hall element.

10. 9. The magnetic sensor according to claim 8, wherein the magnetic field control section has an electromagnetic field control section that generates a magnetic field having a component in the insensitive direction when current is applied, and the electromagnetic field control section is magnetically coupled to the Hall element.

11. The magnetic sensor according to claim 8 , 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 claim 8 , wherein the magnetically sensitive 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 claim 8 , wherein the insensitive direction is along a stacking direction of the Hall element and the magnetic field control unit.

14. the Hall element and the magnetic field control unit are electrically connected to each other; a circuit for energizing the magnetic field control unit and a circuit for measuring a Hall voltage generated in the Hall element by receiving a measurement magnetic field are at least partially common; 2. The magnetic sensor according to claim 1, further comprising a magnetic field calculation unit that obtains the Hall voltage of the Hall element from 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 measures the measured magnetic field, when a control voltage is applied to the magnetic field control unit to control the direction of the magnetic field generated in the Hall element.

15. 2. The magnetic sensor according to claim 1, wherein the Hall element is a film-like body.

16. The magnetic sensor according to claim 15 , wherein the magnetic sensing direction is along a thickness direction of the film body.

17. 16. The magnetic sensor according to claim 15, wherein the magnetically sensitive direction and the insensitive direction are both perpendicular to the thickness direction of the film body.

18. 16. The magnetic sensor according to claim 15, wherein the insensitive direction is along the thickness direction of the film body.

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 a Hall element having a magnetic sensitivity direction that exhibits an anomalous Hall effect; 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, 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, from the variable magnetic field detection unit, a 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; 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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