Magnetic sensor and magnetic measuring method

Abstract

To provide a magnetic sensor and a magnetic measuring method capable of removing 1 / f noise and measuring a small magnetic field with high accuracy.SOLUTION: In a magnetic sensor 1 that comprises a variable magnetic field detection unit 100a including a magnetic detection element 10a having a magneto-sensitive part with a sensitivity axis along a first direction (X direction), a magnetic state variable member 40 capable of entering a first state and a second state with different magnetic states including at least one of effective magnetic permeability and the direction of magnetization, and a magnetic state modulation member 20 for changing the magnetic state of the magnetic state variable member 40: the magnetic detection element 10a may have different measurement sensitivities of a measured magnetic field H along the first direction between when the magnetic state variable member 40 is in the first state and when it is in the second state; and may further include a magnetic field calculation unit 4 for calculating the measured magnetic field H on the basis of a first output from the variable magnetic field detection unit 100a when the magnetic state variable member 40 is in the first state and a second output from the variable magnetic field detection unit 100a when the magnetic state variable member 40 is in the second state.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 Vm 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 Vm 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 is a magnetic sensor characterized by comprising a variable magnetic field detection unit having: a first magnetic body that is magnetized by a measurement magnetic field in a first direction; a magnetic detection element that is located on one side of a first end of the first magnetic body in the first direction and has a sensitivity axis along the first direction; a magnetic state variable member that is located on one side of the first end of the first magnetic body in the first direction and can take a first state and a second state in which the magnetic states differ, including at least one of effective permeability and magnetization direction; and a magnetic state modulation member that changes the magnetic state of the magnetic state variable member.

[0011] In such a magnetic sensor, by using two outputs from the magnetic field detection unit when the magnetic state variable member is in different states, a signal with 1 / f noise removed can be obtained when measuring the measurement magnetic field, which is the external magnetic field to be measured.

[0012] The magnetic sensor may further include a magnetic field calculation unit that calculates the measured magnetic field based on a first output from the variable magnetic field detection unit when the magnetic state variable member is in the first state and a second output from the variable magnetic field detection unit when the magnetic state variable member is in the second state. The magnetic field calculation unit can calculate a signal from which 1 / f noise has been removed.

[0013] In the above magnetic sensor, the effective permeability μ2 in the first direction of the magnetic state changeable member in the second state may be higher than the effective permeability μ1 in the first direction of the magnetic state changeable member in the first state, and may also be higher than the permeability μ0 in the first direction of a first material located between the first magnetic body and the magnetic detection element.

[0014] In this way, because the effective magnetic permeability of the magnetic state changeable member in the second state is higher than that of the surrounding area, the magnetic flux based on the measured magnetic field, i.e., the magnetic flux of the measured magnetic field and the magnetic flux generated when the first magnetic body is magnetized by the measured magnetic field, tends to concentrate in the magnetic state changeable member. As a result, the density of the magnetic flux reaching the magnetically sensitive portion of the magnetic detector element when the magnetic state changeable member is in the second state tends to differ from the density of the magnetic flux reaching the magnetically sensitive portion of the magnetic detector element when the magnetic state changeable member is in the first state.

[0015] In one embodiment (first embodiment) of the above magnetic sensor, the variable magnetic field detection unit may have a non-magnetic member between the magnetic detection element and the magnetic state variable member, and the magnetic sensing portion of the magnetic detection element may be magnetically uncoupled from the magnetic state variable member.

[0016] When the magnetic sensing part of the magnetic detector element and the magnetic state variable member are magnetically uncoupled, in the second state in which the magnetic state variable member is more likely to collect magnetic flux based on the measured magnetic field, the magnetic flux based on the measured magnetic field is less likely to reach the magnetic sensing part of the magnetic detector element.

[0017] In another embodiment (second embodiment) of the magnetic sensor described above, the magnetic sensing portion of the magnetic detector element may be magnetically coupled to the magnetic state variable member.

[0018] When the magnetic sensing part of the magnetic detector element and the magnetic state variable member are magnetically coupled, in the second state in which the magnetic state variable member is more likely to collect magnetic flux based on the measured magnetic field, the magnetic flux based on the measured magnetic field also more easily reaches the magnetic sensing part of the magnetic detector element.

[0019] In the magnetic sensor having the magnetic detector element and the magnetic state changeable member, the magnetic detector element and the magnetic state changeable member may be aligned in a second direction perpendicular to the first direction. In this case, the magnetic state changeable member may have a portion closer to the first magnetic body in the first direction than the detection center of the magnetic detector element. The center of the magnetic state changeable member in the first direction and the detection center of the magnetic detector element may be at the same position in the first direction, and the length of the magnetic state changeable member in the first direction may be longer than the length of the magnetic detector element in the first direction. The length of the first magnetic body in the first direction may be longer than the length in the second direction.

[0020] The variable magnetic field detection unit of the magnetic sensor may further include a second magnetic body that is more distal in the first direction than the magnetic detection element when viewed from the first end.

[0021] By positioning the magnetic detector element between the first magnetic body and the second magnetic body in the first direction, the magnetic flux based on the measured magnetic field can be made to reach the magnetic detector element efficiently.

[0022] In this case, the magnetic state changeable member may be arranged so as to be magnetically coupled to the first magnetic body and the second magnetic body in the second state. In this case, the measurement magnetic field passes preferentially through the magnetically coupled portion consisting of the first magnetic body, the magnetic state changeable member, and the second magnetic body, and therefore the difference in magnetic flux density reaching the magnetically sensitive portion of the magnetic detector element can be increased compared to when the magnetic state changeable member is not magnetically coupled to the first magnetic body or the second magnetic body.

[0023] In the magnetic sensor of the first embodiment or the magnetic sensor of the second embodiment, the magnetic state modulation member and the magnetic state changeable member may form a magnetic control body stacked in a second direction perpendicular to the first direction, and the magnetic control body and the magnetic detector element may be arranged side by side in the second direction. In this case, the magnetic state modulation member may have a spin torque generation unit that imparts a spin orbit torque to the magnetic state changeable member when current is applied, and the magnetic state of the magnetic state changeable member when current is applied may differ from the magnetic state when current is not applied, based on the spin orbit torque from the spin torque generation unit.

[0024] By using spin-orbit torque to change the magnetic state of the magnetic state-variable member, it is possible to increase the degree of difference between the magnetic states of the first and second states and to facilitate switching between states.

[0025] In one specific example (Type A) of using the above spin orbit torque, the variable magnetic field detector may include a bias magnetic field source that magnetizes the magnetic state variable member along the second direction to an extent that the magnetization does not rotate due to the measurement magnetic field when the magnetic state modulation member is in a non-conductive state. In this case, the magnetic state variable member is in the first state when the magnetic state modulation member is in a non-conductive state, and is in the second state when the magnetic state modulation member is in a conductive state and a current flows in an in-plane direction of a first surface having a normal along the second direction, and in the second state, the magnetic state variable member may be magnetized in a direction opposite to the direction of the current flow to an extent that the magnetization can rotate in the in-plane direction of the first surface due to the spin orbit torque caused by a magnetic field based on the measurement magnetic field.

[0026] In the first state, the magnetization direction of the magnetic state changeable member is fixed by the bias magnetic field, so the magnetic field based on the measured magnetic field is less likely to concentrate on the magnetic state changeable member. In contrast, in the second state, the magnetic state changeable member is magnetized by the magnetic flux based on the measured magnetic field, so the magnetic flux based on the measured magnetic field concentrates on the magnetization state changeable member. Therefore, the magnetic flux density reaching the magnetic detector element located around the magnetic state changeable member differs between the first state and the second state.

[0027] In this case, in the second state, the current flowing through the magnetic state modulation member may be along a third direction that is an in-plane direction of the first surface and perpendicular to the first direction, which may reduce hysteresis.

[0028] In a specific example of Type A, the form of the bias magnetic field source is not limited. The magnetic state modulation member may have an antiferromagnetic part made of antiferromagnetic material, and the exchange coupling between the antiferromagnetic part and the magnetic state variable member may serve as the bias magnetic field source. Alternatively, the bias magnetic field source may include at least one of a coil that generates an induced magnetic field when current is applied and a permanent magnet, and in this case, the bias magnetic field source may be laminated on the magnetic control body.

[0029] In another specific example (Type B) of using the above-mentioned spin orbit torque, when the magnetic state modulation member is in an energized state and a current flows along the first direction, the magnetic state variable member is in the first state, and in the first state, the magnetic state variable member is subjected to the spin orbit torque and is magnetized in a third direction perpendicular to the first direction and the second direction by a magnetic flux based on the measured magnetic field, and the magnetization of the magnetic state variable member is less likely to rotate by the magnetic flux based on the measured magnetic field than in the second state, and when the magnetic state modulation member is in a de-energized state, the magnetic state variable member is in the second state, and in the second state, the magnetization of the magnetic state variable member is more likely to orient in the first direction by the magnetic flux based on the measured magnetic field than in the first state.

[0030] In the first state, the magnetization direction of the magnetic state changeable member is fixed based on the spin orbit torque, so the magnetic field based on the measured magnetic field is less likely to concentrate on the magnetic state changeable member. In contrast, in the second state, the magnetic state changeable member is magnetized by the magnetic flux based on the measured magnetic field, so the magnetic flux based on the measured magnetic field concentrates on the magnetization state changeable member. Therefore, the magnetic flux density reaching the magnetic detector element located around the magnetic state changeable member differs between the first state and the second state.

[0031] In a specific example of Type B, the variable magnetic field detection unit may have a bias magnetic field source that applies a bias magnetic field to the magnetic state changeable member. The bias magnetic field source can take various forms, as in the specific example of Type A. In this case, the bias magnetic field that the magnetic state changeable member receives in the second state is along the in-plane direction of a first surface having a normal along the second direction, and it is sufficient that the magnetization of the magnetic state changeable member can be rotated by magnetic flux based on the measured magnetic field.

[0032] In the second state, a bias magnetic field is applied to the magnetic state-changeable member, thereby reducing hysteresis.

[0033] The bias magnetic field is oriented along a third direction perpendicular to the first and second directions, thereby realizing a more stable reduction in hysteresis.

[0034] In another specific example (Type C) of using the above-mentioned spin orbit torque, when the magnetic state modulation member is in an energized state and a current flows along the first direction, the magnetic state variable member is in the first state, and in the first state, the magnetic state variable member is subjected to the spin orbit torque and is magnetized in the first direction and the second direction by a magnetic flux based on the measured magnetic field, and the magnetization of the magnetic state variable member is less likely to rotate by the magnetic flux based on the measured magnetic field than in the second state, and when the magnetic state modulation member is in a de-energized state, the magnetic state variable member is in the second state, and in the second state, the magnetization of the magnetic state variable member is more likely to orient in the first direction by the magnetic flux based on the measured magnetic field than in the first state.

[0035] In the first state, the magnetization direction of the magnetic state changeable member is fixed based on the spin orbit torque, so the magnetic field based on the measured magnetic field is less likely to concentrate on the magnetic state changeable member. In contrast, in the second state, the magnetic state changeable member is magnetized by the magnetic flux based on the measured magnetic field, so the magnetic flux based on the measured magnetic field concentrates on the magnetization state changeable member. Therefore, the magnetic flux density reaching the magnetic detector element located around the magnetic state changeable member differs between the first state and the second state.

[0036] In a specific example of Type C, the variable magnetic field detection unit may have a bias magnetic field source that applies a bias magnetic field to the magnetic state changeable member. In this case, the form of the bias magnetic field source is the same as in the specific example of Type A. The direction and strength of the bias magnetic field are the same as in the specific example of Type B. Specifically, the bias magnetic field may be along an in-plane direction of a first surface having a normal line along the second direction, to an extent that the magnetization of the magnetic state changeable member can be rotated by a magnetic flux based on the measurement magnetic field, or may be along a third direction orthogonal to the first direction and the second direction.

[0037] In another aspect, the present invention provides a magnetic measurement method using a magnetic sensor including a variable magnetic field detection unit having: a first magnetic body that is magnetized by a measurement magnetic field in a first direction; a magnetic detection element that is located on one side of a first end of the first magnetic body in the first direction and has a sensitivity axis along the first direction; a magnetic state changeable member that is located on one side of the first end of the first magnetic body in the first direction and can take a first state and a second state in which the magnetic states differ, including at least one of effective permeability and magnetization direction; and a magnetic state modulation member that changes the magnetic state of the magnetic state changeable member; and a magnetic field calculation unit that calculates the measurement magnetic field from a first output from the variable magnetic field detection unit when the magnetic state changeable member is in the first state and a second output from the variable magnetic field detection unit when the magnetic state changeable member is in the second state. The magnetic measurement method includes a first measurement step of setting the magnetic state variable member to the first state and obtaining the first output when the measurement magnetic field is applied, a second measurement step of setting the magnetic state variable member to the second state and obtaining the second output when the measurement magnetic field is applied, and a magnetic field calculation step of calculating the measurement magnetic field from the first output and the second output in the magnetic field calculation unit.

[0038] The magnetic field calculation step calculates the measured magnetic field based on the first output acquired in the first measurement step and the second output acquired in the second measurement step, thereby obtaining a measured magnetic field from which the 1 / f noise of the magnetoresistive element has been removed. For example, the 1 / f noise can be removed from the first output by using the difference between the first output and the second output in the magnetic field calculation step. [Effects of the Invention]

[0039] 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]

[0040] [Figure 1] 1 is a block diagram of a magnetic sensor according to an embodiment of the present invention; [Figure 2] 3 is an explanatory diagram of a magnetic field detection unit included in the magnetic sensor according to the embodiment of the present invention. FIG. [Figure 3A] 2A and 2B are diagrams illustrating a variable magnetic field detection unit (magnetic state of a magnetic state variable member is in a first state) included in the magnetic sensor according to the first embodiment of the present invention. [Figure 3B] 3A and 3B are diagrams illustrating a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in the magnetic sensor according to the first embodiment of the present invention. [Figure 4] 3 is a flowchart illustrating a magnetic measurement method using the magnetic sensor according to the first embodiment of the present invention. [Figure 5] 3A to 3C are explanatory diagrams illustrating a preferred example of a variable magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. [Figure 6] 5A and 5B are explanatory diagrams illustrating another preferred example of the variable magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. [Figure 7] 5A and 5B are explanatory diagrams of another preferred example of the variable magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. [Figure 8] 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 9] 10 is a diagram illustrating a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in the magnetic sensor according to the second embodiment of the present invention. FIG. [Figure 10] 10A and 10B are diagrams illustrating a preferred example of a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to the second embodiment of the present invention. [Figure 11A] This figure explains the state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) provided in a magnetic sensor according to an example (Example 1-1) in which the variable magnetic field detection unit is Type A and has the configuration of the first embodiment (the magnetic state variable member and the magnetic sensing part of the magnetic detection element are magnetically uncoupled). [Figure 11B]10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in the magnetic sensor according to Example 1-1. FIG. [Figure 12A] 10 is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in the magnetic sensor according to Example 1-1. FIG. [Figure 12B] 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in the magnetic sensor according to Example 1-1. FIG. [Figure 13A] This figure explains the state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) provided in a magnetic sensor according to an example (Example 1-2) in which the variable magnetic field detection unit is Type A and has the configuration of the second embodiment (the magnetic state variable member and the magnetic sensing portion of the magnetic detection element are magnetically coupled). [Figure 13B] 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in the magnetic sensor according to Example 1-2. FIG. [Figure 14A] 10 is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in the magnetic sensor according to Example 1-2. FIG. [Figure 14B] 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in the magnetic sensor according to Example 1-2. FIG. [Figure 15A] This figure explains the state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) provided in a magnetic sensor of an example (Example 2-1) in which the variable magnetic field detection unit is Type B and has the configuration of the first embodiment (the magnetic state variable member and the magnetic sensing part of the magnetic detection element are magnetically uncoupled). [Figure 15B] 2A and 2B are diagrams illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in the magnetic sensor according to Example 2-1. [Figure 16A]10 is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in the magnetic sensor according to Example 2-1. FIG. [Figure 16B] 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to Example 2-1. FIG. [Figure 17A] This figure explains the state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) provided in a magnetic sensor of an example (Example 2-2) in which the variable magnetic field detection unit is Type B and has the configuration of the second embodiment (the magnetic state variable member and the magnetic sensing part of the magnetic detection element are magnetically coupled). [Figure 17B] 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) included in the magnetic sensor according to Example 2-2. FIG. [Figure 18A] 10 is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to Example 2-2. FIG. [Figure 18B] 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to Example 2-2. FIG. [Figure 19A] This figure explains the state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) provided in a magnetic sensor according to an example (Example 3-1) in which the variable magnetic field detection unit is Type C and has the configuration of the first embodiment (the magnetic state variable member and the magnetic sensing part of the magnetic detection element are magnetically uncoupled). [Figure 19B] 3A and 3B are diagrams illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in the magnetic sensor according to Example 3-1. [Figure 20A] 10 is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in the magnetic sensor according to Example 3-1. FIG. [Figure 20B]10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to Example 3-1. FIG. [Figure 21A] This figure explains the state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) provided in a magnetic sensor of an example (Example 3-2) in which the variable magnetic field detection unit is Type C and has the configuration of the second embodiment (the magnetic state variable member and the magnetic sensing portion of the magnetic detection element are magnetically coupled). [Figure 21B] 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) included in the magnetic sensor according to Example 3-2. FIG. [Figure 22A] 10 is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to Example 3-2. FIG. [Figure 22B] 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to Example 3-2. FIG. [Figure 23A] 1-1f is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in a magnetic sensor according to Example 1-1f, which is a modified example of Example 1-1. FIG. [Figure 23B] 2A is a diagram illustrating a state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) included in a magnetic sensor according to Example 2-1f, which is a modified example of Example 2-1. FIG. [Figure 24A] This figure explains the state when a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) provided in a magnetic sensor according to a modified example (Example 1-1M) of Example 1-1, which has a structure similar to that of Example 1-1, but does not have a first magnetic body or a second magnetic body, and has a magnetic attraction layer as part of the magnetic state variable member. [Figure 24B] FIG. 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is a first state) included in a magnetic sensor according to a modified example of Example 1-1M. [Figure 25A] FIG. 10 is a diagram illustrating a state in which a measurement magnetic field is not applied to a magnetic state variable member (magnetic state is in a second state) included in the magnetic sensor according to Example 1-1M. [Figure 25B] FIG. 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is in a second state) included in the magnetic sensor according to Example 1-1M. [Figure 26] This figure explains the state when a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) provided in a magnetic sensor according to a modified example (Example 1-2M) of Example 1-2, which has a structure similar to that of Example 1-2, but does not have a first magnetic body or a second magnetic body, and has a magnetic attraction layer as part of the magnetic state variable member. [Figure 27] FIG. 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is in a second state) included in the magnetic sensor according to Example 1-2M. [Figure 28] This figure explains the state when a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) provided in a magnetic sensor of a modified example (Example 2-1M) of Example 2-1, which has a structure similar to that of Example 2-1, but does not have a first magnetic body or a second magnetic body, and has a magnetic attraction layer as part of the magnetic state variable member. [Figure 29] FIG. 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is in a second state) included in the magnetic sensor according to Example 2-1M. [Figure 30] This figure explains the state when a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) provided in a magnetic sensor of a modified example (Example 2-2M) of Example 2-2, which has a structure similar to that of Example 2-2, but does not have a first magnetic body or a second magnetic body, and has a magnetic attraction layer as part of the magnetic state variable member. [Figure 31] FIG. 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is in a second state) included in the magnetic sensor according to Example 2-2M. [Figure 32]This figure explains the state when a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) provided in a magnetic sensor of a modified example (Example 3-1M) of Example 3-1, which has a structure similar to that of Example 3-1, but does not have a first magnetic body or a second magnetic body, and has a magnetic attraction layer as part of the magnetic state variable member. [Figure 33] FIG. 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is in a second state) included in the magnetic sensor according to Example 3-1M. [Figure 34] This figure explains the state when a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) provided in a magnetic sensor of a modified example (Example 3-2M) of Example 3-2, which has a structure similar to that of Example 3-2, but does not have a first magnetic body or a second magnetic body, and has a magnetic attraction layer as part of the magnetic state variable member. [Figure 35] FIG. 10 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is in a second state) included in the magnetic sensor according to Example 3-2M. [Figure 36] FIG. 10 is a diagram illustrating a state in which the magnetic state variable member is in the second state and before the measurement magnetic field is applied in a magnetic sensor according to Example 2-1m, which is another modified example of Example 2-1. [Figure 37] FIG. 10 is a diagram illustrating a state in which the magnetic state variable member is in a second state and a measurement magnetic field is applied in the magnetic sensor according to Example 2-1m. [Figure 38] FIG. 10 is a diagram illustrating a state in which the magnetic state variable member is in the second state and before the measurement magnetic field is applied in a magnetic sensor according to Example 2-2m, which is another modified example of Example 2-2. [Figure 39] FIG. 10 is a diagram illustrating a state in which the magnetic state variable member is in the second state and a measurement magnetic field is applied in the magnetic sensor according to Example 2-2m. [Figure 40] 10 is an explanatory diagram of a modified example of the variable magnetic field detector according to Example 2-1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0041] 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.

[0042] 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 magnetic field detection unit provided in the magnetic sensor according to one embodiment of the present invention. The magnetic sensor 1 of this embodiment includes a 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 the various units that make up the magnetic sensor 1, and is configured as a CPU (central processing unit), a program, etc.

[0043] The magnetic field detection unit 2 detects an external magnetic field as a measurement target. As shown in FIG. 2, the magnetic field detection unit 2 is configured with a full-bridge circuit 15 composed of magnetic sensor elements 10a, 10b, 10c, and 10d that measure magnetic fields along the X1-X2 direction. In this embodiment, the magnetic field detection unit 2 has variable magnetic field detection units 100a, 100b, 100c, and 100d corresponding to the magnetic sensor elements 10a, 10b, 10c, and 10d, respectively. The control power supply 3 applies a predetermined current or a predetermined voltage to each unit, including the magnetic field detection unit 2, based on a control signal from the control unit 7.

[0044] The magnetic field calculation unit 4 calculates the external magnetic field to be measured (measured magnetic field H) based on the output of the 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 units 100a, 100b, 100c, and 100d when the magnetic state of the magnetic state variable member 40 (described later) is in a first state, and a second output from the variable magnetic field detection units 100a, 100b, 100c, and 100d when the magnetic state of the magnetic state variable member 40 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.

[0045] 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.

[0046] The four magnetic sensor elements 10a, 10b, 10c, and 10d included in the magnetic field detection unit 2 of the magnetic sensor 1 according to one embodiment of the present invention may be provided on the same substrate (one chip). In this embodiment, the four magnetic sensor elements 10a, 10b, 10c, and 10d are provided on the same substrate (not shown), and FIG. 2 is a view of the magnetic field detection unit 2 of the magnetic sensor 1 as viewed from the stacking surface (front surface) of the substrate in the normal direction of the substrate. That is, in FIG. 2, the Z1 side is the front surface of the substrate, and the Z2 side is the back surface of the substrate. The Z direction corresponds to the stacking direction of the magnetic sensor elements 10a, 10b, 10c, and 10d.

[0047] The magnetic field detection unit 2 has a full bridge circuit 15 in which a first half bridge circuit, in which magnetic detector elements 10a and 10b, both of which extend in the Y direction, are connected in series, and a second half bridge circuit, in which magnetic detector elements 10c and 10d, both of which extend in the Y direction, are connected in series, are connected in parallel between a power supply terminal Vdd, which is a power supply feeding point, and a ground terminal GND.

[0048] The first half-bridge circuit has an output terminal V1 between the magnetic detector element 10a and the magnetic detector element 10b. The second half-bridge circuit has an output terminal V2 between the magnetic detector element 10c and the magnetic detector element 10d. The magnitude of the external magnetic field applied from the outside as the measurement magnetic field H can be quantitatively measured based on the potential difference between the outputs from these two output terminals V1 and V2 (midpoint potential Va of the first half-bridge circuit - midpoint potential Vb of the second half-bridge circuit). In this embodiment, the magnetic field detection unit 2 outputs a first signal including the midpoint potential Va from the output terminal V1 and a second signal including the midpoint potential Vb from the output terminal V2. The processing performed by the magnetic field calculation unit 4 includes calculating the midpoint potential difference using these first and second signals as inputs.

[0049] In the pair of magnetic detector elements 10a and 10b forming the first half-bridge circuit, the magnetization 11m of the pinned magnetic layer 11 (see FIG. 3A) is oriented in the X2 direction and the X1 direction, in that order, as indicated by the outline arrows in FIG. 2. In the pair of magnetic detector elements 10c and 10d forming the second half-bridge circuit, the magnetization 11m of the pinned magnetic layer 11 is oriented in the X1 direction and the X2 direction, in that order, as indicated by the outline arrows in FIG. 2.

[0050] In the first half-bridge circuit and the second half-bridge circuit, the magnetization 11m of the fixed magnetic layer 11 of the magnetic detector element 10b and the magnetic detector element 10d on the power supply terminal Vdd side are opposite (anti-parallel). The magnetization 11m of the fixed magnetic layer 11 of the magnetic detector element 10a and the magnetic detector element 10c on the ground terminal GND side are also opposite (anti-parallel). Therefore, the sensitivity axis direction of the magnetic detector elements 10a, 10b, 10c, and 10d is the X direction, which is also referred to as the "first direction" in this specification. The Z direction is also referred to as the "second direction," and the Y direction is also referred to as the "third direction."

[0051] The four magnetic detector elements 10a, 10b, 10c, and 10d have the same magnetization 13m of the free magnetic layer 13 (see FIG. 3A) when no measurement magnetic field H is applied, and are aligned along the Y direction Y2 (hereinafter abbreviated as "Y2 direction"; the same applies to other directions) as indicated by the black arrows in FIG. 2. The method for aligning the magnetization 13m of the free magnetic layer 13 when no measurement magnetic field H is applied is not limited. An external bias magnetic field may be applied, or exchange coupling with an antiferromagnetic layer that interacts with the free magnetic layer 13 may be used.

[0052] With the above-described configuration, the output terminal V1 from the first half-bridge circuit and the output terminal V2 from the second half-bridge circuit change in opposite directions as the magnitude of the measured magnetic field H in the X direction changes. This results in a large output as the potential difference between the two output terminals V1 and V2. Therefore, the magnetic sensor 1 can detect the measured magnetic field H with high accuracy. Note that the full-bridge circuit 15 can be replaced by a first half-bridge circuit or a second half-bridge circuit, or the magnetic sensor element 10a can be used alone.

[0053] 2, the magnetic sensor 1 according to this embodiment includes variable magnetic field detection units 100a, 100b, 100c, and 100d that correspond to the magnetic detection elements 10a, 10b, 10c, and 10d, respectively, and measure the measurement magnetic field H by changing the surrounding magnetic environment. Below, the variable magnetic field detection unit 100a will be described as a specific example.

[0054] (First embodiment) 3A is a diagram illustrating a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in the magnetic sensor according to the first embodiment of the present invention. The variable magnetic field detection unit 100a includes a first magnetic body 31 and a second magnetic body 32 that are magnetized by a measurement magnetic field H along a first direction, a magnetic detection element 10a located between the first magnetic body 31 and the second magnetic body 32 in the first direction, a magnetic state variable member 40 whose magnetic state is changeable, and a magnetic state modulation member 20 that changes the magnetic state of the magnetic state variable member 40. In this specification, the concept of the term "magnetization" used with respect to a magnetic member such as the magnetic state variable member 40 also includes the generation of a magnetic field inside the member based on a physical phenomenon different from the magnetization of a ferromagnetic body (for example, a virtual magnetic field generated based on the topological properties of an antiferromagnetic body).

[0055] The first magnetic body 31 and the second magnetic body 32 may be made of any material as long as they can be magnetized in the first direction by the measurement magnetic field H along the first direction. Specific examples include magnetic materials such as CoFe alloy and NiFe alloy (nickel-iron alloy). The first magnetic body 31 and the second magnetic body 32 function as magnetic collectors (yokes) that collect and magnetize the measurement magnetic field H in the first direction. As shown in FIG. 3A , when the measurement magnetic field H is oriented toward one side of the first direction, specifically the X1 direction, the measurement magnetic field H is collected by the first magnetic body 31 and magnetizes the first magnetic body 31. As a result, a magnetic flux (hereinafter also referred to as "measurement magnetic flux Φ") with a density higher than that of the measurement magnetic field H is generated in the first magnetic body 31. This measurement magnetic flux Φ is emitted in the first direction from the first end 311, which is the end of the first magnetic body 31 on the first orientation side (X1 side). The magnetic permeability μ0 of the insulator 50 made of a first material and located around the first magnetic body 31 and the second magnetic body 32 is sufficiently lower than the magnetic permeability of the first magnetic body 31 and the second magnetic body 32, so the measurement magnetic flux Φ emitted in the first direction from the first end 311 also diffuses in the second and third directions within the first material, but converges to the end of the second magnetic body 32 on the X2 side.

[0056] The magnetic detector 10a is located in a first orientation relative to a first end 311, which is the end of the first magnetic body 31 on the first orientation side (X1 side), and has a sensitivity axis along the first direction. Specific examples of the magnetic detector 10a include magnetoresistive elements such as giant magnetoresistive elements (GMR) and tunneling magnetoresistive elements (TMR), and Hall elements. FIG. 3A shows a giant magnetoresistive element (GMR) as a specific example of the magnetic detector 10a. The magnetic detector 10a is located between the first magnetic body 31 and the second magnetic body 32. In other words, the second magnetic body 32 is located farther from the magnetic detector 10a in the first direction (X direction) than the first end 311 of the first magnetic body 31. The first magnetic body 31 and the second magnetic body 32 collect the measurement magnetic field H in the first direction (X direction) and increase the magnetic flux density between the first magnetic body 31 and the second magnetic body 32, so that the magnetic detection element 10a has higher magnetic resolution than when the first magnetic body 31 and the second magnetic body 32 are not provided.

[0057] The magnetic sensor element 10a, which is a giant magnetoresistance effect element, has a pinned magnetic layer 11, a free magnetic layer 13, and an intermediate layer 12 formed between the pinned magnetic layer 11 and the free magnetic layer 13. The pinned magnetic layer 11 is made of a magnetic material such as a CoFe alloy (cobalt-iron alloy). The intermediate layer 12 is made of a non-magnetic material such as Cu. The free magnetic layer 13 is made of a soft magnetic material such as a CoFe alloy or a NiFe alloy (nickel-iron alloy) and is formed as a single-layer structure, a laminated structure, a laminated ferrimagnetic structure, or the like. When the magnetic sensor element 10a is made of a tunnel magnetoresistance effect element, the intermediate layer 12 is an insulating barrier layer made of MgO, Al2O3, titanium oxide, or the like.

[0058] The resistance value of the magnetic sensor element 10a changes depending on the relative relationship between the magnetization directions of the fixed magnetic layer 11, in which the direction of magnetization 11m is fixed, and the free magnetic layer 13, which is a magnetic sensing part whose direction and magnitude of magnetization 13m change in response to an external magnetic field. The variable magnetic field detection unit 100a of the magnetic sensor 1 can measure the direction and strength of an external magnetic field based on changes in the resistance value of the magnetic sensor element 10a. In this embodiment, the free magnetic layer 13 is located on the Z2 side of the magnetic sensor element 10a, and the detection center 10P of the magnetic sensor element 10a is located at the center of the free magnetic layer 13.

[0059] The magnetic state variable member 40 is a member that can be in a first state and a second state, which differ in magnetic state including at least one of effective permeability and direction of magnetization 40m, and the magnetic state is controlled by the magnetic state modulating member 20. The magnetic state variable member 40 is located closer to the first orientation (X1 side) than the first end 311 of the first magnetic body 31, and in the example shown in Fig. 3A, it is located between the first magnetic body 31 and the second magnetic body 32 in the first direction.

[0060] Although the magnetic state changeable member 40, which is made of an antiferromagnetic material, has a relative permeability of approximately 1 or less, as described above, a magnetic field stronger than the external magnetic field may be generated inside the magnetic state changeable member 40. In this case, the magnetic state changeable member 40 experiences a magnetic flux collection phenomenon, collecting the external magnetic field within itself. Therefore, in this specification, the "effective magnetic permeability" of the magnetic state changeable member 40 is evaluated based on its magnetic flux collection function when subjected to an external magnetic field in a predetermined direction. For example, if the relative permeability around the magnetic state changeable member 40 is 1, and the magnetic state changeable member 40 also has the function of collecting the external magnetic field when subjected to an external magnetic field having a component along the first direction, the effective relative permeability of the magnetic state changeable member 40 in the first direction is determined to be greater than 1. Therefore, if the effective relative permeability of the magnetic state changeable member 40 in the first direction exceeds 1 as described above, the magnetic flux density around it will be reduced due to the magnetic flux collection function of the magnetic state changeable member 40.

[0061] In one specific example, the magnetic state variable member 40 has an effective magnetic permeability μ2 in the first direction (X direction) in the second state that is higher than the effective magnetic permeability μ1 in the first direction (X direction) in the first state. Also, the effective magnetic permeability μ2 in the first direction (X direction) in the second state is higher than the magnetic permeability μ0 in the first direction (X direction) of a first material located between the first magnetic body 31 and the magnetic detection element 10a. In this embodiment, an insulator 50 is located as the first material.

[0062] In the first embodiment, the magnetic state variable member 40 and the magnetic state modulation member 20 are stacked in the second direction (Z direction) to form the magnetic control body 60, and a non-magnetic member 41 is provided between the magnetic control body 60 and the magnetic detection element 10a, and the non-magnetic member 41 magnetically decouples the magnetic state variable member 40 of the magnetic control body 60 from the free magnetic layer 13 of the magnetic detection element 10a.

[0063] (First state) As shown in FIG. 3A , the measurement magnetic field H is collected by the first magnetic body 31, which functions as a yoke. This magnetic field magnetizes the first magnetic body 31, causing a measurement magnetic flux Φ to be emitted from the first end 311 of the first magnetic body 31. In the first state, the effective permeability μ1 of the magnetic state variable member 40 in the X direction is not significantly different from the permeability μ0 of the insulator 50. Therefore, the measurement magnetic flux Φ is emitted from the first end 311 of the first magnetic body 31 while diffusing, having a component in the X1 direction as well as components in the second direction (Z direction) and the third direction (Y direction). The measurement magnetic flux Φ then converges between the first magnetic body 31 and the second magnetic body 32, with the components in the second direction and the third direction becoming smaller, and reaches the second magnetic body 32, which is located closer to the X1 side than the first magnetic body 31. A portion of the measurement magnetic flux Φ that diffuses and converges in this manner reaches the free magnetic layer 13 of the magnetic sensor element 10a and is measured by the magnetic sensor element 10a.

[0064] (Second state) FIG. 3B is a diagram illustrating a variable magnetic field detector included in the magnetic sensor according to the first embodiment of the present invention (the magnetic state of the magnetic state changeable member is in the second state). In the second state, the effective permeability μ2 of the magnetic state changeable member 40 in the X direction is higher than the permeability μ0 of the insulator 50. Therefore, the measurement magnetic flux Φ emitted from the first end 311 preferentially passes through the magnetic state changeable member 40. As the measurement magnetic flux Φ concentrates on the magnetic state changeable member 40, the density of the measurement magnetic flux Φ reaching the free magnetic layer 13 decreases compared to the first state. As a result, the measurement sensitivity of the magnetic sensor element 10a located near the magnetic state changeable member 40 to the measurement magnetic flux Φ decreases. Therefore, the second output from the variable magnetic field detector in the second state has the same noise signal strength as the first output in the first state, but the signal strength based on the measurement magnetic flux Φ decreases. Note that FIG. 3B illustrates a case in which the magnetic state changeable member 40 is made of an antiferromagnetic material.

[0065] 4 is a flowchart illustrating a magnetic measurement method using a magnetic sensor according to the first embodiment of the present invention. As shown in FIG. 4, in a first measurement step, a control signal is output from the control power supply 3 to the control unit 7, and a signal is output to set the magnetic state of the magnetic state variable member 40 in each of the variable magnetic field detectors 100a-100d included in the magnetic field detector 2 to a first state. Measurements are then performed by the magnetic detector elements 10a, 10b, 10c, and 10d with the magnetic state variable member 40 in the first state, and first outputs are obtained from each of the variable magnetic field detectors 100a, 100b, 100c, and 100d. These signals cause the magnetic field detector 2 to output a first signal (a signal including midpoint potential Va from output terminal V1) and a second signal (a signal including midpoint potential Vb from output terminal V2) (step S101). These two signals output from the magnetic field detection unit 2 are input to the magnetic field calculation unit 4, and are stored in the magnetic field calculation unit 4 or in a memory not shown, either as these signals or as a midpoint potential difference signal, which is the difference between the two signals.

[0066] Next, in a second measurement step, a control signal is output from the control power supply 3 to change the magnetic state of the magnetic state variable member 40 of each of the variable magnetic field detectors 100a, 100b, 100c, and 100d of the magnetic field detector 2 to a second state. The magnetic state variable member 40 is then changed to the second state, and measurements are performed by the magnetic detector elements 10a, 10b, 10c, and 10d. Second outputs are obtained from each of the variable magnetic field detectors 100a, 100b, 100c, and 100d. These signals cause the magnetic field detector 2 to output a first signal and a second signal (step S102). The measurement times for steps S101 and S102 are both significantly shorter than 1 second (e.g., 0.3 seconds), and the time required for steps S101 and S102 is also significantly shorter than 1 second (e.g., 0.7 seconds). For this reason, steps S101 and S102 are performed in an environment in which 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. The two signals output from the magnetic field detection unit 2 are input to the magnetic field calculation unit 4, and stored in the magnetic field calculation unit 4 or in a memory (not shown) either as they are or as a midpoint potential difference signal, which is the difference between the two signals.

[0067] Next, the magnetic field calculation unit 4 performs a process (step S103) to calculate the difference between the signal based on the first output (a signal including the midpoint potential difference in the first state) and the signal based on the second output (a signal including the midpoint potential difference in the second state) stored in the magnetic field calculation unit 4 or a memory (not shown) in steps S101 and S102. If the signals stored in the magnetic field calculation unit 4 or a memory (not shown) are the first and second signals before the midpoint potential difference is calculated, the magnetic field calculation unit 4 performs a process to calculate the difference between the first and second signals in the first state to obtain a signal including the midpoint potential difference in the first state, and a process to calculate the difference between the first and second signals in the second state to obtain a signal including the midpoint potential difference in the second state, and then performs a process to calculate the difference between these two signals including the midpoint potential difference. By performing the above process, the magnetic field calculation unit 4 obtains a measurement signal from which 1 / f noise has been appropriately removed. The measurement signal is amplified by the amplifier 5 and converted into a digital signal by the A / D conversion circuit 6. Therefore, the measurement signal obtained by the magnetic measurement method using the magnetic sensor 1 of this embodiment has 1 / f noise properly removed, and therefore the resolution (magnetic resolution) of the signal based on the measured magnetic flux Φ is higher than that of the signal based on the first output (signal including the midpoint potential difference in the first state) or the signal based on the second output (signal including the midpoint potential difference in the second state).

[0068] In this embodiment, since the magnetic field detection unit 2 has the full bridge circuit 15, the signals to be processed to find the difference in the magnetic field calculation unit 4 are the signal of the midpoint potential difference in the first state based on the first output and the signal of the midpoint potential difference in the second state based on the second output, but the signals to be processed by the magnetic field calculation unit 4 are set appropriately depending on the output signal from the magnetic field detection unit 2. For example, if the magnetic field detection unit 2 has only one variable magnetic field detection unit 100a, the magnetic field calculation unit 4 will find the difference between the first signal and the second signal from the variable magnetic field detection unit 100a.

[0069] (Layout) It is preferable that the positional relationship between the magnetic detector element 10a and the magnetic state variable member 40 is set so that the degree of difference between the signal based on the measured magnetic flux Φ included in the first output and the signal based on the measured magnetic flux Φ included in the second output becomes large.

[0070] From this perspective, the magnetic detector element 10a and the magnetic state variable member 40 may be aligned in a second direction (Z direction) perpendicular to the first direction (X direction). In this arrangement, a change in the magnetic state of the magnetic state variable member 40 is likely to appear as a change in the strength of the measurement magnetic flux Φ that reaches the detection center 10P of the magnetic detector element 10a.

[0071] It is preferable that the magnetic state changeable member 40 has a portion closer to the first magnetic body 31 in the first direction (X direction) than the detection center 10P of the magnetic detection element 10a. With this arrangement, in the second state, the measurement magnetic flux Φ emitted from the first end 311 easily reaches the magnetic state changeable member 40 that is relatively closer in the first direction, so that the magnetic flux is efficiently concentrated on the magnetic state changeable member 40 in the second state. From this perspective, it is preferable that the length of the magnetic state changeable member 40 in the first direction be longer than the length of the magnetic detection element 10a in the first direction (X direction).

[0072] The center of the magnetic state variable member 40 in the first direction (X direction) and the detection center 10P of the magnetic detector element 10a are preferably located at the same position in the first direction (X direction). With this arrangement, the magnetic flux in the first direction (X direction) that the magnetic state variable member 40 in the first state can exert on the magnetic detector element 10a is likely to be equal to the magnetic flux in the first direction that the magnetic state variable member 40 in the second state can exert on the magnetic detector element 10a. This increases the correlation between the noise signals included in the first output and the noise signals included in the second output, which is expected to improve the noise removal efficiency of the measurement signal obtained by the magnetic field calculation unit 4. From the perspective of consistently improving the noise removal efficiency of the measurement signal and improving the operational stability of the magnetic state variable member 40, it may be preferable for the center of the magnetic state variable member 40 and the center of the magnetic state modulation member 20 to be aligned in the first direction (X direction).

[0073] The length of the magnetic state variable member 40 in the first direction (X direction) is preferably longer than the length of the magnetic detection element 10a in the first direction (X direction). In this arrangement, a part of the X2 side of the magnetic state variable member 40 is located between the first end 311 and the magnetic detection element 10a in the first direction (X direction), and therefore the magnetic flux density reaching the magnetic detection element 10a is easily affected by the magnetic state of the magnetic state variable member 40.

[0074] From the viewpoint of more reliably realizing that the magnetic flux density reaching the magnetic detector element 10a is more susceptible to the magnetic state of the magnetic state variable member 40, it is preferable that the magnetic state variable member 40 is arranged so that the first magnetic body 31 and the second magnetic body 32 are magnetically coupled in the second state. FIG. 5 is an explanatory diagram of a preferred example of a variable magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. In the example shown in FIG. 5, when viewed from the second direction (Z direction), the magnetic state variable member 40 is arranged so that it is magnetically coupled to the first magnetic body 31 and the second magnetic body 32 in the second state. Specifically, the magnetic state variable member 40 has a portion overlapping with the first magnetic body 31 and a portion overlapping with the second magnetic body 32. 5, the measurement magnetic flux Φ generated by magnetization of the first magnetic body 31 flows almost directly from the magnetic coupling portion between the magnetic state changeable member 40 and the first magnetic body 31 into the magnetic state changeable member 40 in the second state, and flows almost directly from the magnetic coupling portion between the magnetic state changeable member 40 and the first magnetic body 31 to the second magnetic body 32. Therefore, the measurement magnetic flux Φ does not substantially contain a component that reaches the magnetic detector element 10a, and only noise signals tend to be measured by the magnetic detector element 10a.

[0075] FIG. 6 is an explanatory diagram of another preferred example of a variable magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. In the configuration shown in FIG. 6, the arrangement of the components of the magnetic sensor element 10a is reversed in the Z direction compared to the configuration shown in FIG. 5. That is, in FIG. 5, the free magnetic layer 13 of the magnetic sensor element 10a is located on the side closer to the magnetic control body 60 (Z2 side), whereas in FIG. 6, the fixed magnetic layer 11 of the magnetic sensor element 10a is located on the side closer to the magnetic control body 60 (Z2 side). Therefore, in the configuration shown in FIG. 6, the detection center 10P of the magnetic sensor element 10a is closer to the center of the first magnetic body 31 and the second magnetic body 32 in the second direction (Z direction) than in the configuration shown in FIG. 5. Therefore, it is expected that the intensity of the component in the X1 direction of the measurement magnetic flux Φ reaching the detection center 10P of the magnetic sensor element 10a in the first state will be relatively high.

[0076] FIG. 7 is an explanatory diagram of another preferred example of the variable magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. In the configuration shown in FIG. 7, the positional relationship between the magnetic detector element 10a and the magnetic control body 60 in the second direction (Z direction) is reversed compared to the configuration shown in FIG. 5. That is, in FIG. 5, the magnetic detector element 10a is located closer to the Z1 side than the magnetic control body 60, whereas in FIG. 7, the magnetic detector element 10a is located closer to the Z2 side than the magnetic control body 60. Therefore, in the configuration shown in FIG. 7, the detection center 10P of the magnetic detector element 10a is farther from the center of the first magnetic body 31 and the second magnetic body 32 in the second direction (Z direction) than in the configuration shown in FIG. 5. Therefore, in the second state, the intensity of the measurement magnetic flux Φ reaching the detection center 10P of the magnetic detector element 10a is expected to be particularly low. Furthermore, as viewed from the first end 311, the magnetic detection element 10a is located behind the magnetic control body 60. Therefore, even if part of the measurement magnetic flux Φ is emitted from the first end 311 to the insulator 50, the magnetic control body 60 acts as a magnetic shield, making it difficult for the magnetic flux to reach the magnetic detection element 10a. Therefore, in the second state, only noise signals are likely to be measured by the magnetic detection element 10a.

[0077] 8 is an explanatory diagram of a modified example of the variable magnetic field detection unit included in the magnetic sensor according to the first embodiment of the present invention. The structure of the modified example shown in FIG. 8 is different from the structure shown in FIG. 3A in that the second magnetic body 32 is omitted. In this case, the absence of the second magnetic body 32 reduces the intensity of the measurement magnetic flux Φ, thereby reducing the sensitivity of the magnetic detection element 10a. However, it is possible to reduce the footprint (projected area on the XY plane) of the variable magnetic field detection unit 100a. Although the second magnetic body 32 is omitted in the structure shown in FIG. 8, the first magnetic body 31 may also be omitted.

[0078] When the measurement magnetic field H is a magnetic field in the first direction (X direction), it is preferable that the length of the first magnetic body 31 in the first direction (X direction) is longer than the length in the second direction (Z direction). When the length relationship is reversed (length in the first direction < length in the second direction), there is a higher possibility of detecting a magnetic field in the second direction (Z direction).

[0079] (Second embodiment) FIG. 9 is a diagram illustrating a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in a magnetic sensor according to a second embodiment of the present invention. In contrast to the first embodiment, the second embodiment does not include a non-magnetic member 41, and the magnetic state variable member 40 and the free magnetic layer 13 are magnetically coupled. Therefore, in the second embodiment, the magnetic state variable member 40 essentially functions as the free magnetic layer 13 in the second state. Therefore, in the second state, the detection sensitivity of the magnetic detection element 10a is directly affected by the magnetic state of the magnetic state variable member 40.

[0080] For example, in the second state, the effective permeability μ2 of the magnetic state changeable member 40 in the first direction is higher than the permeability μ0 of the surrounding insulator 50, and therefore the measurement magnetic flux Φ is preferentially concentrated in the magnetic state changeable member 40, as shown in Fig. 9. In this case, part of the measurement magnetic flux Φ that is magnetized in the magnetic state changeable member 40 and travels in the X1 direction also passes through the free magnetic layer 13 that is magnetically coupled to the magnetic state changeable member 40, and its direction has a component in the X1 direction. Therefore, in the second embodiment, the intensity of the measurement magnetic flux Φ that reaches the free magnetic layer 13 may be higher in the second state than in the first state.

[0081] In contrast, in the first state, the effective permeability μ1 of the magnetic state changeable member 40 in the first direction is equivalent to the permeability μ0 of the surrounding insulator 50, so the degree of collection of the measurement magnetic flux Φ by the magnetic state changeable member 40 is lower than in the second state. Therefore, even if the measurement magnetic flux Φ reaches the free magnetic layer 13 magnetically coupled to the magnetic state changeable member 40, the magnetic flux density thereof will be lower than in the second state.

[0082] Thus, in the second embodiment, the measurement magnetic flux Φ is more likely to reach the free magnetic layer 13 in the second state than in the first state. Therefore, in the second embodiment, a measurement signal from which noise signals have been removed can be obtained by subtracting the first output obtained in the first state from the second output obtained in the second state.

[0083] In the second embodiment, the magnetic state changeable member 40 and the free magnetic layer 13 are magnetically coupled, and therefore the magnetic state changeable member 40 and the free magnetic layer 13 may be made of the same material, with one member (the variable free magnetic layer) fulfilling the functions of both the magnetic state changeable member 40 and the free magnetic layer 13. In this case, the intermediate layer 12 and the fixed magnetic layer 11 may be stacked on a portion of the surface of the variable free magnetic layer facing the Z1 side, thereby constituting a magnetic detection element 10a having a magnetoresistive effect element structure. The variable free magnetic layer may be made of the same material as the material constituting the magnetic state changeable member 40. Therefore, the term "magnetization" used with respect to the variable free magnetic layer has a broader meaning than the magnetization of a ferromagnetic material and includes, for example, a virtual magnetic field based on the topological properties of an antiferromagnetic material.

[0084] FIG. 10 is a diagram illustrating a preferred example of a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to the second embodiment of the present invention. In the example shown in FIG. 10, similar to the example shown in FIG. 5, in the second state, the magnetic state variable member 40 is magnetically coupled to the first magnetic body 31 and the second magnetic body 32. Therefore, in the second state, the free magnetic layer 13 is magnetically coupled to the first magnetic body 31 and the second magnetic body 32. Therefore, in the second state, the measurement magnetic flux Φ reaches the free magnetic layer 13 particularly efficiently.

[0085] In the variable magnetic field detection unit 100a of the magnetic sensor 1 according to the embodiment of the present invention, the density of the measurement magnetic flux Φ that reaches the free magnetic layer 13 differs between a first state in which the effective magnetic permeability of the magnetic state variable member 40 in the first direction is relatively low and a second state in which the effective magnetic permeability is relatively high. Whether the state in which the measurement magnetic flux Φ that reaches the free magnetic layer 13 is relatively high is the first state or the second state depends on the specific configuration.

[0086] Below, the detailed operation of the variable magnetic field detection unit 100a will be explained using as specific examples three configurations: a configuration (Type A) in which current is passed through the magnetic state modulation member 20 along the third direction (Y direction) to magnetize the magnetic state modulation member 20 in the third direction (Y direction), a configuration (Type B) in which current is passed through the magnetic state modulation member 20 along the first direction (X direction) to magnetize the magnetic state modulation member 20 in the third direction (Y direction), and a configuration (Type C) in which current is passed through the magnetic state modulation member 20 along the third direction (Y direction) to magnetize the magnetic state modulation member 20 in the second direction (Z direction), all of which share the same configuration in which current is passed through the magnetic state modulation member 20 to apply a spin orbit torque to the magnetic state modulation member 40 and magnetize the magnetic state modulation member 40 in a predetermined direction.

[0087] (Example 1-1) FIG. 11A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to an example (Example 1-1) having a configuration in which the variable magnetic field detection unit is Type A and the first embodiment (the magnetic state variable member 40 and the magnetic sensing portion of the magnetic detection element are magnetically uncoupled). FIG. 11B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in the magnetic sensor according to Example 1-1. In the variable magnetic field detection unit 100a shown in FIGS. 11A and 11B, the first magnetic body 31, the second magnetic body 32, and the insulator 50 are not shown (the same applies below). In addition, in FIG. 11B, the wiring and the like shown in FIG. 11A are not shown.

[0088] In Example 1-1, the magnetic state modulation member 20 has a spin torque generating unit that generates the spin Hall effect, the Rashba-Edelstein effect, or the like by passing a current through the magnetic state modulation member 20 in the XY in-plane direction, and applies a spin orbit torque to the magnetic state variable member 40. In this example, as shown in FIG. 11A , a control wiring 61 is provided so that a current (a control current 20c described later) from a control current source I, which is part of the control power supply 3, is applied to the magnetic state modulation member 20 in the third direction (Y direction). In addition, a measurement wiring 62 is provided so that a voltage from a measurement voltage source V, which is part of the control power supply 3, is applied between the free magnetic layer 13 and the fixed magnetic layer 11 of the magnetoresistive effect element 10a in the second direction (Z direction) for the purpose of measuring the electrical characteristics of the magnetoresistive effect element 10a. In this example, the magnetoresistive effect element 10a and the magnetic control body 60 are stacked in the second direction (Z direction), and since the magnetic control body 60 is made of a conductive material, the measurement wiring 62 is provided so that a voltage from the measurement voltage source V is applied to the free magnetic layer 13 via the magnetic control body 60.

[0089] In this example, the magnetic state modulation member 20 may be a film-like body, and the entire body may be composed of a spin torque generation unit. In the configuration shown in Fig. 11A, the magnetic state modulation member 20 is composed of a spin torque generation unit. Materials for the spin torque generation unit 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, and Ir); 1-x Tr xExamples 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 thereof. The spin torque generation portion may be composed of a single-phase film or a laminated film. In the case of a laminated film, a boundary region may be formed between adjacent films.

[0090] The magnetic state variable member 40 is made of a material that can rotate the magnetization 40m of the magnetic state variable member 40 when subjected to spin orbit torque from the magnetic state modulation member 20. 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). The magnetic state variable member 40 may be made of a single-phase film or a laminated film. In the case of a laminated film, a boundary region may be formed between adjacent films.

[0091] The non-magnetic member 41 may be made of an organic material or an inorganic material. In the case of an inorganic material, it may be made of a conductive material such as Cu or Ru, or an insulating material such as an oxide or nitride. The non-magnetic member 41 may be integral with the insulator 50.

[0092] In the variable magnetic field detection unit 100a according to this example, the magnetic state modulation member 20 has an antiferromagnetic portion made of an antiferromagnetic material. Specifically, the entire magnetic state modulation member 20 is made of an antiferromagnetic portion. Therefore, when the magnetic state modulation member 20 is in a non-energized state, as shown in FIG. 11A, the magnetization 40m of the magnetic state variable member 40 is oriented in the Z1 direction due to the exchange coupling 20af with the magnetic state modulation member 20 (antiferromagnetic portion). Because the thickness is small in the Z direction, the magnetization 40m is unlikely to rotate. Therefore, the magnetization 40m of the magnetic state variable member 40 is essentially fixed in the Z1 direction, and the effective permeability in the X direction, which is the direction in which the measurement magnetic field H is applied, is low. Therefore, in the X direction, the effective permeability μ1 of the magnetic state variable member 40 is almost the same as the permeability μ0 of the surrounding insulator 50, and the magnetic state variable member 40 is in the first state.

[0093] When the measurement magnetic field H is applied in this first state, the measurement magnetic flux Φ does not concentrate on the magnetic state variable member 40. Therefore, as shown in Fig. 11B, a considerable amount of the measurement magnetic flux Φ reaches the free magnetic layer 13, and the magnetic detection element 10a measures this reaching magnetic flux.

[0094] 12A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to Example 1-1. FIG. 12B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) included in the magnetic sensor according to Example 1-1. In FIG. 12B, the wiring and the like shown in FIG. 12A are not shown.

[0095] In the second state, a current 20c is passed from the control current source I through the control wiring 61 to the magnetic state modulation member 20 in the Y direction, specifically the Y1 direction, to bring the magnetic state modulation member 20 into a conducting state. As a result, due to the spin Hall effect or the like, spins unevenly distributed in one direction in the X direction are accumulated on the Z1 side of the magnetic state modulation member 20 and injected into the magnetic state variable member 40. The angular momentum of the accumulated spins is directly transferred, causing a torque to act on the magnetization 40m of the magnetic state variable member 40, i.e., a spin orbit torque is generated, and the magnetization 40m is oriented in the Y2 direction.

[0096] At this time, the magnetization 40m of the magnetic state changeable member 40 is oriented in the in-plane direction of the XY plane (first plane) perpendicular to the thickness direction of the magnetic state changeable member 40, and therefore the magnetization 40m can be rotated in the XY plane by the measured magnetic flux Φ. That is, in the second state, the magnetic state changeable member 40 has an effective permeability μ2 in the X direction that is higher than the effective permeability μ1 in the X direction in the first state (μ2>μ1).

[0097] 12B, when a measurement magnetic field H is applied, the magnetization 40m of the magnetic state variable member 40 rotates along the measurement magnetic flux Φ and becomes oriented in the X1 direction, causing the magnetic state variable member 40 to have a magnetic collecting function, and the measurement magnetic flux Φ is concentrated in the magnetic state variable member 40. In this way, the measurement magnetic flux Φ that reached the free magnetic layer 13 when the magnetic state modulation member 20 was in a non-conductive state is concentrated in the magnetic state variable member 40 by applying a current 20c to the magnetic state modulation member 20. Therefore, in the second state, the measurement magnetic flux Φ is less likely to reach the magnetic detection element 10a than in the first state.

[0098] As described above, in Example 1-1, the measurement magnetic flux Φ is more likely to reach the magnetic detection element 10a in the first state than in the second state, and therefore, by subtracting the second output from the first output in the magnetic field calculation unit 4, a measurement signal in which 1 / f noise has been appropriately removed can be obtained.

[0099] (Example 1-2) FIG. 13A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to an example (Example 1-2) having a configuration in which the variable magnetic field detection unit is Type A and the second embodiment (the magnetic state variable member 40 and the magnetic sensing portion of the magnetic detection element are magnetically coupled). FIG. 13B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to Example 1-2. FIG. 14A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 1-2. FIG. 14B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 1-2. In FIGS. 13B and 14B, the wiring and the like shown in FIGS. 13A and 14A are omitted.

[0100] The variable magnetic field detecting unit 100a according to Example 1-2 differs from the variable magnetic field detecting unit 100a according to Example 1-1 in that it does not have the non-magnetic member 41, but the other configurations are the same. Therefore, in the variable magnetic field detecting unit 100a according to Example 1-2, the magnetic state variable member 40 and the free magnetic layer 13 are magnetically coupled. Therefore, as shown in FIG. 13A , in a first state, which is a non-energized state in which no current is applied to the magnetic state modulation member 20, the exchange coupling 20af between the portion made of an antiferromagnetic material in the magnetic state modulation member 20 and the magnetic state variable member 40 causes the magnetization 40m of the magnetic state variable member 40 and the magnetization 13m of the free magnetic layer 13 magnetically coupled to the magnetic state variable member 40 to be oriented in the Z1 direction.

[0101] Because the thickness of the free magnetic layer 13 in the Z direction is small, the magnetization 13m is unlikely to rotate. Therefore, the magnetization 40m of the magnetic state variable member 40 and the magnetization 13m of the free magnetic layer 13 are essentially fixed in the Z1 direction. In other words, the effective magnetic permeability in the X direction of the magnetic state variable member 40 and the free magnetic layer 13 is almost the same as the magnetic permeability μ0 of the surrounding insulator 50.

[0102] Even if a measurement magnetic flux Φ is received in this state, as shown in FIG. 13B, the magnetization 13m of the free magnetic layer 13 is unlikely to rotate along the X direction, which is the sensitivity axis direction, and therefore the measurement magnetic flux Φ is unlikely to be measured by the magnetic detection element 10a.

[0103] On the other hand, in the second state, which is a state in which a current 20c in the Y1 direction is passed from the control current source I through the control wiring 61 to the magnetic state modulation member 20, spin injection from the magnetic state modulation member 20 to the magnetic state variable member 40 occurs as in Example 1-1, causing a spin orbit torque to be generated in the magnetic state variable member 40, and the magnetization 40m of the magnetic state variable member 40 is aligned in the Y2 direction, as shown in Fig. 14A. Because the magnetic state variable member 40 and the free magnetic layer 13 are magnetically coupled, the magnetization 13m of the free magnetic layer 13 is also aligned in the Y2 direction.

[0104] The directions of the magnetization 40m and magnetization 13m are in the XY plane, which is perpendicular to the thickness of the magnetic state changeable member 40 and the free magnetic layer 13, and therefore the direction of the magnetization 40m of the magnetic state changeable member 40 and the direction of the magnetization 13m of the free magnetic layer 13 can both be rotated in the XY plane by the measured magnetic flux Φ. That is, the magnetic state changeable member 40 and the free magnetic layer 13 are in a state where the effective magnetic permeability in the X direction is high.

[0105] 14B, the magnetization 40m of the magnetic state changeable member 40 rotates along the measurement magnetic flux Φ and becomes oriented in the X1 direction, which gives the magnetic state changeable member 40 a magnetic collecting function, and the measurement magnetic flux Φ is concentrated in the magnetic state changeable member 40. Here, because the magnetic state changeable member 40 is magnetically coupled to the free magnetic layer 13, the magnetic flux oriented in the X1 direction, which has a higher density than in the first state (FIG. 13B), reaches the free magnetic layer 13 under the influence of the magnetization 40m of the magnetic state changeable member 40.

[0106] In this way, in the second state of Example 1-2, when the measurement magnetic field H is applied, the free magnetic layer 13 is magnetized more strongly in the X1 direction than in the first state, and therefore the measurement sensitivity of the measurement magnetic field H of the magnetic detection element 10a is relatively higher in the second state. Therefore, by subtracting the first output from the second output in the magnetic field calculation unit 4, it is possible to obtain a measurement signal from which 1 / f noise has been appropriately removed.

[0107] In Examples 1-1 and 1-2, in the first state, the magnetization 40m of the magnetic state variable member 40 is oriented in the Z1 direction due to the exchange coupling 20af with the magnetic state modulation member 20 acting as a bias magnetic field source. However, the bias magnetic field source that aligns the magnetization 40m of the magnetic state variable member 40 in a predetermined direction in the first state is not limited to this. The magnetization 40m of the magnetic state variable member 40 may be oriented in the Z direction using an induced magnetic field from a current-carrying coil or a magnetic field from a permanent magnet as a bias magnetic field. Even in such cases, it is sufficient that in the second state, the magnetization 40m of the magnetic state variable member 40 is oriented in the Y direction based on the application of current to the magnetic state modulation member 20. From the viewpoint of increasing the correlation between the noise components included in the first signal and the noise components included in the second signal, it may be preferable that there is no difference in the bias magnetic field from the bias magnetic field source between the first state and the second state.

[0108] Example 2-1 FIG. 15A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to an example (Example 2-1) having a configuration in which the variable magnetic field detection unit is Type B and the first embodiment (the magnetic state variable member 40 and the magnetic sensing unit of the magnetic detection element are magnetically uncoupled). FIG. 15B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to Example 2-1. FIG. 16A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 2-1. FIG. 16B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 2-1. In FIGS. 15B and 16B, the wiring and the like shown in FIGS. 15A and 16A are omitted.

[0109] The variable magnetic field detecting unit 100a according to Example 2-1, like the variable magnetic field detecting unit 100a according to Example 1-1, has a non-magnetic member 41, and the magnetic state variable member 40 is not magnetically coupled to the free magnetic layer 13. Furthermore, the variable magnetic field detecting unit 100a according to Example 2-1 differs from the variable magnetic field detecting unit 100a according to Example 1-1 in that the control wiring 61 is provided so that a current from a control current source I, which is part of the control power supply 3, is applied to the magnetic state modulation member 20 in the X direction (the Y direction in Example 1-1).

[0110] In the first state, a current 20c flows from the control current source I through the control wiring 61 to the magnetic state modulation member 20 in the X direction, specifically, the X1 direction, to establish a current-carrying state. The application of current causes spin injection from the magnetic state modulation member 20 to the magnetic state variable member 40, resulting in a spin orbit torque in the magnetic state variable member 40, as in Example 1-1. As shown in FIG. 15A, the magnetization 40m of the magnetic state variable member 40 is strongly aligned in the Y2 direction. In the variable magnetic field detection unit 100a of Example 2-1, a bias magnetic field source 21, which is made of a permanent magnet or the like and whose magnetic field 21m is oriented in the Y1 direction, is stacked on the Z2 side of the magnetic state modulation member 20. In other words, the bias magnetic field source 21 forms a stacked structure with the magnetic control body 60. When no current 20c flows through the magnetic state modulation member 20, the bias magnetic field source 21 generates a magnetization 40m oriented in the Y2 direction (see FIG. 16A).

[0111] 15B, even if the measurement magnetic flux Φ is applied to the magnetic state changeable member 40, the magnetization 40m of the magnetic state changeable member 40 is unlikely to rotate along the X direction. That is, the magnetic state changeable member 40 has a low effective magnetic permeability μ1 in the X direction, which is equivalent to the magnetic permeability μ0 of the surrounding insulator 50. Therefore, the magnetic state changeable member 40 is unlikely to affect the measurement magnetic flux Φ that reaches the free magnetic layer 13 of the magnetic sensor element 10a, and the magnetic sensor element 10a measures the measurement magnetic flux Φ in a magnetic environment similar to that when the magnetic state changeable member 40 is not present (i.e., is replaced by the insulator 50).

[0112] On the other hand, in the second state, the application of the current 20c to the magnetic state modulation member 20 is stopped, placing the magnetic state modulation member 20 in a non-energized state. As a result, as shown in FIG. 16A , the magnetic state modulation member 20 no longer controls the orientation of the magnetization 40m of the magnetic state variable member 40. Therefore, the magnetic field 21m of the bias magnetic field source 21 aligns the magnetization 40m of the magnetic state variable member 40 in the Y2 direction, but to a weaker degree than in the first state. Therefore, when the magnetic state variable member 40 receives a measurement magnetic flux Φ oriented in the X1 direction, the magnetization 40m easily rotates in the XY plane and becomes oriented in the X1 direction. Therefore, the effective magnetic permeability μ2 in the X direction of the magnetic state variable member 40 in the second state is higher than the magnetic permeability μ0 of the surrounding insulator 50.

[0113] 16B, when the measurement magnetic field H is applied in this state, the magnetization 40m of the magnetic state variable member 40 rotates along the measurement magnetic flux Φ and becomes oriented in the X1 direction, which causes the magnetic state variable member 40 to have a magnetic collecting function, and the measurement magnetic flux Φ is concentrated in the magnetic state variable member 40. As a result, the density of the measurement magnetic flux Φ that reaches the free magnetic layer 13 of the magnetic detection element 10a decreases, and the measurement sensitivity of the measurement magnetic field H in the variable magnetic field detection unit 100a decreases compared to the first state.

[0114] Thus, in Example 2-1, the measurement magnetic flux Φ is more likely to reach the magnetic detection element 10a in the first state than in the second state, and therefore, by subtracting the second output from the first output in the magnetic field calculation unit 4, a measurement signal from which 1 / f noise has been appropriately removed can be obtained.

[0115] (Example 2-2)

[0116] FIG. 17A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to an example (Example 2-2) having a configuration in which the variable magnetic field detection unit is Type B and the second embodiment (the magnetic state variable member 40 and the magnetic sensing portion of the magnetic detection element are magnetically coupled). FIG. 17B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to Example 2-2. FIG. 18A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 2-2. FIG. 18B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 2-2. Wiring and the like shown in FIGS. 17A and 18A are omitted in FIGS. 17B and 18B.

[0117] The variable magnetic field detecting unit 100a according to Example 2-2 differs from the variable magnetic field detecting unit 100a according to Example 2-1 in that it does not have the non-magnetic member 41, but the other configurations are the same. Therefore, in the variable magnetic field detecting unit 100a according to Example 2-2, the magnetic state variable member 40 and the free magnetic layer 13 are magnetically coupled. Therefore, as shown in FIG. 17A , in a first state, which is a current-carrying state in which a current 20c flows from the control current source I through the control wiring 61 to the magnetic state modulation member 20 in the X1 direction, a spin orbit torque is generated in the magnetic state variable member 40, and the magnetization 40m of the magnetic state variable member 40 is strongly aligned in the Y2 direction. In addition, in the free magnetic layer 13 magnetically coupled to the magnetic state variable member 40, the magnetization 13m is also strongly aligned in the Y2 direction.

[0118] Therefore, even if the measurement magnetic flux Φ is applied to the magnetic state changeable member 40, the magnetization 40m of the magnetic state changeable member 40 is unlikely to rotate along the X direction, as shown in FIG. 17B. That is, the magnetic state changeable member 40 has a low effective magnetic permeability μ1 in the X direction, which is equivalent to the magnetic permeability μ0 of the surrounding insulator 50. In Example 2-2, the magnetic state changeable member 40 and the free magnetic layer 13 are magnetically coupled, and therefore the free magnetic layer 13 also has a low effective magnetic permeability in the X direction. Therefore, even when the measurement magnetic flux Φ is applied, the free magnetic layer 13 is unlikely to be magnetized in the X1 direction, resulting in a reduced measurement sensitivity of the measurement magnetic field H in the variable magnetic field detection unit 100a.

[0119] On the other hand, in the second state, the application of the current 20c to the magnetic state modulation member 20 is stopped, resulting in a non-energized state. As a result, as shown in FIG. 18A, the magnetic state modulation member 20 no longer controls the direction of the magnetization 40m of the magnetic state variable member 40. In Example 2-2, the bias magnetic field source 21, such as a permanent magnet, is stacked on the Z2 side of the magnetic state modulation member 20. Therefore, the magnetic field 21m generated by the bias magnetic field source 21 aligns the magnetization 40m of the magnetic state variable member 40 in the Y2 direction, but to a lesser extent than in the first state. Therefore, the effective magnetic permeability in the X direction of the magnetic state variable member 40 and the free magnetic layer 13 magnetically coupled thereto in the second state is higher than the magnetic permeability μ0 of the surrounding insulator 50.

[0120] 18B, the magnetization 40m of the magnetic state changeable member 40 rotates along the measurement magnetic flux Φ and becomes oriented in the X1 direction, which gives the magnetic state changeable member 40 a magnetic collecting function, and the measurement magnetic flux Φ is concentrated in the magnetic state changeable member 40. Here, because the magnetic state changeable member 40 is magnetically coupled to the free magnetic layer 13, the magnetic flux oriented in the X1 direction, which has a higher density than in the first state (FIG. 17B), reaches the free magnetic layer 13 under the influence of the magnetization 40m of the magnetic state changeable member 40.

[0121] In this way, in the second state of Example 2-2, when the measurement magnetic field H is applied, the free magnetic layer 13 is magnetized more strongly in the X1 direction than in the first state, and therefore the measurement sensitivity of the measurement magnetic field H of the magnetic detection element 10a is relatively higher in the second state. Therefore, by subtracting the first output from the second output in the magnetic field calculation unit 4, it is possible to obtain a measurement signal from which 1 / f noise has been appropriately removed.

[0122] In the examples (Examples 2-1 and 2-2) having the above-described Type B configuration, the bias magnetic field source 21 was a permanent magnet, but is not limited to this. The bias magnetic field may be a magnetic field based on exchange coupling or an induced magnetic field from a current-carrying coil, and a member that provides these magnetic fields can serve as the bias magnetic field source 21. Furthermore, while current is applied to the magnetic state modulation member 20 in the X1 direction in the first state, it may also be in the X2 direction. As a result, the magnetization 40m of the magnetic state variable member 40 is oriented in the Y1 direction, and in this case too, the magnetization 40m is unlikely to rotate even when subjected to a measurement magnetic flux Φ with a large component in the X1 direction.

[0123] Although the bias magnetic field applied to the magnetic state variable member 40 in the second state was oriented in the Y2 direction, this is not limiting. It is sufficient that the magnetic state variable member 40 is magnetized in a direction that makes it easy to magnetize it with the measurement magnetic flux Φ, and from this perspective, it may be preferable for the bias magnetic field to be oriented in the in-plane direction of the XY plane. Since the measurement magnetic flux Φ has the largest component oriented in the X1 direction, from the perspective of reducing hysteresis, it may be preferable for the bias magnetic field to be oriented along the X direction, i.e., in the X1 or X2 direction.

[0124] Example 3-1 19A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to an example (Example 3-1) having a configuration in which the variable magnetic field detection unit is Type C and the first embodiment (the magnetic state variable member 40 and the magnetic sensing unit of the magnetic detection element are magnetically uncoupled). FIG. 19B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to Example 3-1. FIG. 20A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 3-1. FIG. 20B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 3-1. In FIGS. 19B and 20B, the wiring and the like shown in FIGS. 19A and 20A are omitted.

[0125] The variable magnetic field detecting unit 100a according to Example 3-1, like the variable magnetic field detecting unit 100a according to Example 1-1, has a non-magnetic member 41, and the magnetic state variable member 40 is not magnetically coupled to the free magnetic layer 13. On the other hand, they have in common the point that a control wiring 61 is provided so that a current from a control current source I, which is part of the control power supply 3, can be applied to the magnetic state modulation member 20 in the Y direction.

[0126] In the first state, a current 20c is passed from the control current source I through the control wiring 61 to the magnetic state modulation member 20 in the Y direction, specifically the Y1 direction, to establish a conducting state. The application of current causes spin injection from the magnetic state modulation member 20 to the magnetic state variable member 40, and as in Example 1-1, a spin orbit torque is generated in the magnetic state variable member 40, and as shown in Fig. 19A, the magnetization 40m of the magnetic state variable member 40 is strongly aligned in the Z1 direction.

[0127] When the magnetic state changeable member 40 is aligned in the thickness direction (Z direction) in this way, its magnetization 40m does not change easily. Therefore, even if a measurement magnetic flux Φ is applied to the magnetic state changeable member 40, the magnetization 40m of the magnetic state changeable member 40 is unlikely to rotate along the X direction, as shown in FIG. 19B. That is, the magnetic state changeable member 40 has a low effective magnetic permeability μ1 in the X direction, which is equivalent to the magnetic permeability μ0 of the surrounding insulator 50. Therefore, the magnetic state changeable member 40 is unlikely to affect the measurement magnetic flux Φ that reaches the free magnetic layer 13 of the magnetic sensor element 10a, and the measurement magnetic flux Φ is measured in the magnetic sensor element 10a in a magnetic environment similar to that when the magnetic state changeable member 40 is not present (or is replaced by the insulator 50).

[0128] On the other hand, in the second state, the application of the current 20c to the magnetic state modulation member 20 is stopped, resulting in a non-energized state. As a result, as shown in FIG. 20A , the magnetic state modulation member 20 no longer controls the direction of the magnetization 40m of the magnetic state variable member 40. In Example 3-1, the magnetic state modulation member 20 is made of an antiferromagnetic material. The exchange coupling 20af of this magnetic state modulation member 20 functions as a bias magnetic field source, and the magnetic state variable member 40 is relatively weakly magnetized in the Y2 direction. Therefore, the magnetic state variable member 40 in the second state can be magnetized in the X direction more easily than in the first state, and the effective permeability μ2 of the magnetic state variable member 40 in the X direction is higher than the permeability μ0 of the surrounding insulator 50.

[0129] 20B, when the measurement magnetic field H is applied, the magnetization 40m of the magnetic state variable member 40 rotates along the measurement magnetic flux Φ and becomes oriented in the X1 direction, which gives the magnetic state variable member 40 a magnetic collecting function, and the measurement magnetic flux Φ is concentrated in the magnetic state variable member 40. As a result, the density of the measurement magnetic flux Φ that reaches the free magnetic layer 13 of the magnetic detection element 10a decreases, and the measurement sensitivity of the measurement magnetic field H in the variable magnetic field detection unit 100a decreases compared to the first state.

[0130] Thus, in Example 3-1, the measurement magnetic flux Φ is more likely to reach the magnetic detection element 10a in the first state than in the second state, and therefore, by subtracting the second output from the first output in the magnetic field calculation unit 4, a measurement signal from which 1 / f noise has been appropriately removed can be obtained.

[0131] (Example 3-2) FIG. 21A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to an example (Example 3-2) having a configuration in which the variable magnetic field detection unit is Type C and the second embodiment (the magnetic state variable member 40 and the magnetic sensing portion of the magnetic detection element are magnetically coupled). FIG. 21B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a first state) included in a magnetic sensor according to Example 3-2. FIG. 22A is a diagram illustrating a state before a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 3-2. FIG. 22B is a diagram illustrating a state after a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in a second state) included in a magnetic sensor according to Example 3-2. Wiring and the like shown in FIGS. 21A and 22A are omitted in FIGS. 21B and 22B.

[0132] The variable magnetic field detecting unit 100a according to Example 3-2 differs from the variable magnetic field detecting unit 100a according to Example 3-1 in that it does not have the non-magnetic member 41, but the other configurations are the same. Therefore, in the variable magnetic field detecting unit 100a according to Example 3-2, the magnetic state variable member 40 and the free magnetic layer 13 are magnetically coupled. Therefore, as shown in FIG. 21A , in the first state, which is a current-carrying state in which a current 20c in the Y1 direction flows from the control current source I through the control wiring 61 to the magnetic state modulation member 20, a spin orbit torque is generated in the magnetic state variable member 40, causing the magnetization 40m of the magnetic state variable member 40 to align in the Z1 direction. In addition, in the free magnetic layer 13 magnetically coupled to the magnetic state variable member 40, the magnetization 13m is also strongly aligned in the Z1 direction.

[0133] Therefore, even if the measurement magnetic flux Φ is applied to the magnetic state variable member 40, the magnetization 40m of the magnetic state variable member 40 is unlikely to rotate along the X direction, as shown in FIG. 21B. That is, the magnetic state variable member 40 has a low effective magnetic permeability μ1 in the X direction, which is equivalent to the permeability μ0 of the surrounding insulator 50. In Example 3-2, the magnetic state variable member 40 and the free magnetic layer 13 are magnetically coupled, and therefore the free magnetic layer 13 also has a low effective magnetic permeability in the X direction. Therefore, even when the measurement magnetic flux Φ is applied, the free magnetic layer 13 is unlikely to be magnetized in the X1 direction, resulting in a reduced measurement sensitivity of the measurement magnetic field H in the variable magnetic field detection unit 100a.

[0134] On the other hand, in the second state, the application of the current 20c to the magnetic state modulation member 20 is stopped to set the magnetic state modulation member 20 to a non-energized state. As a result, as shown in FIG. 22A , the magnetic state modulation member 20 no longer controls the direction of the magnetization 40m of the magnetic state variable member 40. In Example 3-2, the magnetic state modulation member 20 has a portion made of an antiferromagnetic material. Due to the exchange coupling 20af between this antiferromagnetic material and the magnetic state variable member 40, the magnetization 40m of the magnetic state variable member 40 is oriented in the Y2 direction, but the degree of magnetization is relatively weak. Based on the magnetization of the magnetic state variable member 40, the magnetization 13m of the free magnetic layer 13 magnetically coupled to the magnetic state variable member 40 is also oriented in the Y2 direction, and the degree of magnetization is relatively weak, similar to the magnetization 40m of the magnetic state variable member 40. Therefore, the magnetic state variable member 40 and the free magnetic layer 13 in the second state can be magnetized in the X direction more easily than in the first state. That is, the effective magnetic permeability μ2 of the magnetic state variable member 40 in the X direction is higher than the magnetic permeability μ0 of the surrounding insulator 50.

[0135] 22B, the magnetization 40m of the magnetic state changeable member 40 rotates along the measurement magnetic flux Φ and becomes oriented in the X1 direction, causing the magnetic state changeable member 40 to have a magnetic collecting function, and the measurement magnetic flux Φ is concentrated in the magnetic state changeable member 40. Here, the free magnetic layer 13 is magnetically coupled to the magnetic state changeable member 40, and therefore, under the influence of the magnetization 40m of the magnetic state changeable member 40, magnetic flux oriented in the X1 direction, which has a higher density than in the first state (FIG. 21B), reaches the free magnetic layer 13.

[0136] As described above, in the second state of Example 3-2, when the measurement magnetic field H is applied, the free magnetic layer 13 is magnetized more strongly in the X1 direction than in the first state, and therefore the measurement sensitivity of the measurement magnetic field H of the magnetic detection element 10a is relatively higher in the second state. Therefore, by subtracting the first output from the second output in the magnetic field calculation unit 4, it is possible to obtain a measurement signal from which 1 / f noise has been appropriately removed.

[0137] In the examples (Examples 3-1 and 3-2) having the above-described Type C configuration, the exchange coupling 20af serves as the bias magnetic field source to apply the bias magnetic field, but this is not limiting. The bias magnetic field may be a magnetic field from a permanent magnet or an induced magnetic field from a current-carrying coil, and a component that applies these magnetic fields may serve as the bias magnetic field source 21. Furthermore, while current is applied to the magnetic state modulation member 20 in the Y2 direction in the first state, it may also be in the Y1 direction. As a result, the magnetization 40m of the magnetic state variable member 40 is oriented in the Z2 direction, but even in this case, the magnetization 40m is unlikely to rotate even when subjected to a measurement magnetic flux Φ with a large component oriented in the X1 direction.

[0138] Although the bias magnetic field applied to the magnetic state changeable member 40 in the second state was oriented in the Y2 direction, this is not limiting. Any direction is sufficient as long as the magnetization 40m of the magnetic state changeable member 40, which has been set in a predetermined direction by the bias magnetic field, is easily rotated along the direction of the measurement magnetic flux Φ when the magnetic state changeable member 40 is subjected to the measurement magnetic flux Φ. From this perspective, it may be preferable for the bias magnetic field to be oriented in the XY plane. Since the measurement magnetic flux Φ has the largest component oriented in the X1 direction, from the perspective of reducing hysteresis, it may be preferable for the bias magnetic field to be oriented along the X direction, i.e., in the X1 or X2 direction.

[0139] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

[0140] In the above description, the stacking direction of the magnetic state variable member 40 and the magnetic state modulation member 20 in the magnetic control unit 60 and the arrangement direction of the magnetic detection element 10a and the magnetic control unit 60 were both in the second direction, but this is not limited thereto. For example, the magnetic state variable member 40 and the magnetic state modulation member 20 may be stacked in the first direction or the third direction. Furthermore, the boundary between the magnetic state variable member 40 and the magnetic state modulation member 20 in the magnetic control unit 60 was described as a plane parallel to the XY plane, but this is not limited thereto. The plane formed by the boundary may have a portion inclined with respect to the XY plane. Specific examples of such cases include a configuration in which the boundary is flat but inclined with respect to the XY plane, a configuration in which the boundary is curved, a configuration in which the boundary has a bent portion, and a configuration in which the boundary forms a pattern when viewed from the stacking direction. Furthermore, the wiring for applying current to the magnetic state modulation member 20 may share part of the wiring for measuring the electrical characteristics of the magnetic detection element, thereby simplifying the overall circuit.

[0141] Furthermore, in the above description, the magnetization 40m of the magnetic state variable member 40 rotates due to the spin orbit torque from the magnetic state modulation member 20, but this is not limited to this, and the magnetization 40m of the magnetic state variable member 40 may also rotate due to the spin transfer torque, or both the spin orbit torque and the spin transfer torque may contribute to the rotation of the magnetization 40m of the magnetic state variable member 40.

[0142] In particular, when the magnetic control body 60 has an electromagnetically-conductive state variable member 601 that combines the functions of the magnetic state variable member 40 and the magnetic state modulation member 20, as shown in Figures 23A and 23B, by passing a current 601c through the electromagnetically-conductive state variable member 601, both the spin-orbit torque and the spin transfer torque may contribute, causing the magnetization 601m of the electromagnetically-conductive state variable member 601 to rotate. The electromagnetically-conductive state variable member 601 has a portion made of, for example, an antiferromagnetic material, and in the example shown in Figures 23A and 23B, the electromagnetically-conductive state variable member 601 is an integrated structure (without a laminated structure) made of an antiferromagnetic material. Note that in Figure 23A and subsequent figures, wiring and the like shown in Figure 11A and the like are omitted.

[0143] Note that Figure 23A is a diagram illustrating the state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the second state) provided in a magnetic sensor of Example 1-1f, which is a modified example of Example 1-1 (the state shown in Figure 12B in Example 1-1), and Figure 23B is a diagram illustrating the state in which a measurement magnetic field is applied to a variable magnetic field detection unit (the magnetic state of the magnetic state variable member is in the first state) provided in a magnetic sensor of Example 2-1f, which is a modified example of Example 2-1 (the state shown in Figure 15B in Example 2-1).

[0144] As described above, in Examples 1-1f and 2-1f, the direction of magnetization 601m of the electromagnetically-conductive state variable member 601 when the electromagnetically-conductive state variable member 601 is de-energized is controlled by utilizing the magnetic anisotropy of the electromagnetically-conductive state variable member 601 or by modifying the manufacturing process. Specifically, in Example 1-1f, the electromagnetically-conductive state variable member 601 may be magnetized in the Z1 direction, similar to the magnetic state variable member 40 of FIG. 11A, by using magnetocrystalline anisotropy (the magnetization of crystal grains is in the Z direction as the easy magnetization direction) or magnetic field deposition (deposition while applying a magnetic field in the Z direction). In Example 2-1f, the electromagnetically-conductive state variable member 601 may have a shape that is longer in the Y direction than in other directions. In this case, the magnetic anisotropy (shape magnetic anisotropy) resulting from this shape anisotropy can be used to magnetize the electromagnetically-conductive state variable member 601 in the Y2 direction, similar to the magnetic state variable member 40 of FIG. 15A.

[0145] It may be preferable that the electromagnetically conductive state variable member 601 has a portion made of an antiferromagnetic material. The electromagnetically conductive state variable member 601 can also be applied to other embodiments (Example 1-2, Example 2-2, Example 3-1, Example 3-3) and their modified examples (such as Example 1-1M described below). In any of the examples, when the electromagnetically conductive state variable member 601 is used, the magnetic state when the electromagnetically conductive state variable member 601 is not conducting may be set based on the magnetocrystalline anisotropy and / or shape magnetic anisotropy of the electromagnetically conductive state variable member 601.

[0146] In the above description including the examples, the variable magnetic field detecting unit 100a includes the first magnetic body 31 and / or the second magnetic body 32, but it is not necessary to include both magnetic bodies. In this case, the variable magnetic field detecting unit 100a has a configuration in which the magnetic detecting element 10 and the magnetic control body 60 are arranged side by side in the Z direction and are disposed inside the insulator 50. This configuration is similar to the configuration shown in FIG. 11B etc., but in comparison with FIG. 11B, the first magnetic body 31 is not provided, and therefore a measuring magnetic field H is applied to the magnetic detecting element 10a and the magnetic state modulation member 20 instead of the measuring magnetic flux Φ.

[0147] In the above description, including the examples, the magnetic state variable member 40 has a single-phase structure, but it may have a multi-phase structure of multiple materials as long as they have a common tendency in response to an external magnetic field (specifically, the direction of magnetization) (magnetically integrated). Specific examples of such a structure include a laminated structure and a dispersed structure. A detailed description will be given below, using the drawings, of a specific example of a magnetic state variable member 40 having a laminated structure. It may also have magnetic bodies aligned in a direction (a second direction, e.g., a Z direction perpendicular to the first direction) that intersects the first direction (X direction). A description will be given below of a case in which such a magnetic body (magnetic attracting layer 42) is provided, using the drawings.

[0148] 24A is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is a first state) included in a magnetic sensor according to a modified example (Example 1-1M) of Example 1-1, which has a structure similar to that of Example 1-1, but does not include a first magnetic body and a second magnetic body, and instead includes a magnetic attraction layer as part of the magnetic state variable member. FIG. 24B is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is a first state) included in a magnetic sensor according to a modified example of Example 1-1M. FIG. 25A is a diagram illustrating a state in which a measurement magnetic field is not applied to a magnetic state variable member (magnetic state is a second state) included in a magnetic sensor according to Example 1-1M, and FIG. 25B is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is a second state) included in a magnetic sensor according to Example 1-1M.

[0149] 24A and 25A and 25B, the variable magnetic field detecting unit 100a according to Example 1-1M differs from the variable magnetic field detecting unit 100a according to Example 1-1 (see FIG. 11A, etc.) in that the first magnetic body 31 and the second magnetic body 32 are not provided, and that a magnetically attracting layer 42 is disposed between the non-magnetic member 41 and the magnetic state variable member 40. In FIG. 24A and 25A and 25B, in order to clarify that the magnetically attracting layer 42 is part of the magnetic state variable member 40, the member designated by the reference numeral 40 in Example 1 has been renamed to a spin receptor 43, and it is clearly shown that the magnetic state variable member 40 consists of the magnetically attracting layer 42 and the spin receptor 43. In this example, the magnetic state variable member 40 has a magnetically attracting layer 42 aligned in a direction (a second direction, for example, the Z direction perpendicular to the first direction) intersecting the magnetic detection element 10a with the first direction (the X direction), and another member (a spin receptor 43 in this example) aligned in the second direction (the Z direction) with the magnetically attracting layer 42, and the magnetically attracting layer 42 and the spin receptor 43 are magnetically coupled to each other. In other words, the magnetic state variable member 40 has a layered structure of the spin receptor 43 and the magnetically attracting layer 42, and they are magnetically integrated.

[0150] The magnetically inducing layer 42 is made of the same magnetic material as the first magnetic body 31, for example, a soft magnetic material. It has a sufficiently higher magnetic permeability (for example, a relative magnetic permeability of 3000 or more) than the magnetic permeability μ0 of the insulator 50 (not shown in FIG. 24 ) and is magnetized under the influence of an external magnetic field. Such soft magnetic materials are relatively easy to obtain and manufacture. Therefore, if the spin receptor 43 has a portion made of an antiferromagnetic material that generates a virtual magnetic field and the magnetically inducing layer 42 stacked on the spin receptor 43 is made of a soft magnetic material, the magnetic state variable member 40 can be manufactured with high production efficiency.

[0151] 24A , when the bias magnetic field based on the exchange coupling 20af causes the magnetization 43m of the spin receptor 43 to be oriented in the Z1 direction, the magnetization 42m of the magnetically inductive layer 42 is oriented in the Z1 direction, along with the direction of the magnetization 43m. As a result, the magnetic state variable member 40, which is magnetically integrated and made up of the magnetically inductive layer 42 and the spin receptor 43, enters the first state, in which the effective permeability in the X direction is low. Therefore, the measurement magnetic field H in the X1 direction does not concentrate on the magnetic state variable member 40, and the measurement magnetic field H in the X1 direction reaches the magnetic detector element 10a. Therefore, the magnetic detector element 10a can measure the strength of the measurement magnetic field H.

[0152] As shown in FIG. 25A, when the magnetic state variable member 40 enters the second state by passing current through the magnetic state modulation member 20, the magnetization 43m of the spin receptor 43 of the magnetic state variable member 40 is oriented in the Y2 direction, and the magnetization 42m of the magnetically coupled spin receptor 43 is also oriented in the Y2 direction. When a measurement magnetic field H is applied in this state, as shown in FIG. 25B, a magnetic flux Φ' oriented in the X1 direction is generated in the magnetically attracted layer 42, including the rotation of the magnetization 42m in the XY plane. Therefore, the measurement magnetic field H oriented in the X1 direction is unlikely to reach the magnetic sensor element 10a, and the measurement magnetic field H is not substantially measured by the magnetic sensor element 10a. The magnetic flux Φ' is emitted from the end 421 on the X1 side of the magnetically attracted layer 42.

[0153] From the viewpoint of efficiently concentrating the measurement magnetic field H on the magnetically attracting layer 42, it is preferable that the length of the magnetically attracting layer 42 in the first direction (X direction) be equal to or greater than the length of the magnetic detecting element 10a, which is the magnetic detecting element, in the first direction (X direction). In addition, since the material of the magnetically attracting layer 42 is often easier to obtain than the material of the spin receptor 43, it may be preferable that both ends of the spin receptor 43 in the first direction (X direction) overlap the magnetically attracting layer 42 when viewed in the second direction (Z direction). In Figures 25A and 25B, the length of the spin receptor 43 in the first direction (X direction) is equal to the length of the magnetically attracting layer 42 in the first direction (X direction), so both ends of the spin receptor 43 in the first direction (X direction) overlap with the ends of the magnetically attracting layer 42 in the first direction (X direction). However, the length of the spin receptor 43 in the first direction (X direction) may be shorter than the length of the magnetically attracting layer 42 in the first direction (X direction), so that both ends of the spin receptor 43 in the first direction (X direction) overlap with parts of the magnetically attracting layer 42 other than the ends in the first direction (X direction).

[0154] 24A, the exchange coupling 20af between the magnetic state modulation member 20 and the spin receptor 43 generates the magnetization 43m of the spin receptor 43, and this magnetization 43m generates the magnetization 42m of the magnetically inducing layer 42. However, this is not limiting. As shown in FIG. 24B, the spin receptor 43 may have a portion made of an antiferromagnetic material, and the exchange coupling 43af between the spin receptor 43 and the magnetically inducing layer 42 based on this portion may function as a bias magnetic field source. In this case, the magnetization 42m generated in the magnetically inducing layer 42 based on the exchange coupling 43af causes the magnetic state variable member 40 to enter the first state. In the configuration shown in FIG. 24A, the magnetic state modulation member 20 needs to have a portion made of an antiferromagnetic material to generate the exchange coupling interaction. However, in the configuration shown in FIG. 24B, the magnetic state modulation member 20 does not need to have a portion made of an antiferromagnetic material and can be made only of a paramagnetic material such as W (tungsten). Such structural variations are also applicable to Examples 1-2M, 3-1M, and 3-2M, which will be described later.

[0155] Fig. 26 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) included in a magnetic sensor according to a modified example (Example 1-2M) of Example 1-2, which has a structure similar to that of Example 1-2 but does not include a first magnetic body and a second magnetic body and instead includes a magnetic attraction layer as part of the magnetic state variable member. Fig. 27 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is second state) included in a magnetic sensor according to Example 1-2M.

[0156] 26 and 27, unlike Example 1-1M, the nonmagnetic member 41 is not provided, and therefore the free magnetic layer 13, which is the magnetically sensitive portion of the magnetic detection element 10a, and the magnetically inductive layer 42 are magnetically coupled. In FIG. 26, the bias magnetic field based on the exchange coupling 20af between the magnetic state modulation member 20 and the spin receptor 43 causes the magnetization 43m of the spin receptor 43 to be oriented in the Z1 direction, and the magnetically inductive layer 42 magnetically connected to the spin receptor 43 generates a magnetization 42m oriented in the Z1 direction along the magnetization 43m in the magnetically inductive layer 42. As a result, the magnetically integrated magnetic state variable member 40, which is made up of the magnetically inductive layer 42 and the spin receptor 43, enters the first state in which the effective permeability in the X direction is low, and the magnetization 13m of the free magnetic layer 13 is oriented in the Z1 direction, along the direction of the magnetization 40m of the magnetic state variable member 40. Therefore, as shown in FIG. 26, even when the free magnetic layer 13 receives the measurement magnetic field H, it is not magnetized along the direction of the measurement magnetic field H, and the measurement magnetic field H is not substantially measured by the magnetic detection element 10a.

[0157] 27, when the magnetization 43m of the spin receptor 43 of the magnetic state variable member 40 is oriented in the X1 direction by applying current to the magnetic state modulation member 20, the magnetization 42m of the magnetically inductive layer 42 is also oriented in the X1 direction along the direction of the magnetization 43m. As a result, the magnetically integrated magnetic state variable member 40, consisting of the magnetically inductive layer 42 and the spin receptor 43, enters the second state in which the effective permeability in the X direction is high. Therefore, a magnetic flux Φ' oriented in the X1 direction is generated in the magnetically inductive layer 42, including the rotation of the magnetization 42m in the XY plane. The magnetic flux Φ' oriented in the X1 direction also passes through the free magnetic layer 13 magnetically coupled to the magnetic state variable member 40, and the magnetization 13m of the free magnetic layer 13 is oriented in the X1 direction along the magnetic flux Φ' . Therefore, the magnetic flux Φ', which is the magnetic flux based on the measurement magnetic field H, is measured in the magnetic detection element 10a. The magnetic flux Φ′ is emitted from the end 421 of the magnetic induction layer 42 on the X1 side.

[0158] Fig. 28 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) included in a magnetic sensor according to a modified example (Example 2-1M) of Example 2-1, which has a structure similar to that of Example 2-1 but does not include a first magnetic body and a second magnetic body and instead includes a magnetic attraction layer as part of the magnetic state variable member. Fig. 29 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is second state) included in a magnetic sensor according to Example 2-1M.

[0159] 28 and 29, the variable magnetic field detecting unit 100a according to Example 2-1M is different from the variable magnetic field detecting unit 100a according to Example 2-1 (see FIG. 15A, etc.) in that the first magnetic body 31 and the second magnetic body 32 are not provided, and that a magnetically inducing layer 42 is disposed between the non-magnetic member 41 and the magnetic state variable member 40. As shown in FIG. 28, when the magnetization 43m of the spin receptor 43 is oriented in the Y2 direction by applying current to the magnetic state modulation member 20, the magnetization 42m of the magnetically inducing layer 42 is oriented in the Y2 direction along the direction of the magnetization 43m. As a result, the magnetic state variable member 40, which is magnetically integrated and consists of the magnetic attraction layer 42 and the spin receptor 43, enters the first state in which the effective permeability in the X direction is low, so that the measurement magnetic field H in the X1 direction does not concentrate on the magnetic state variable member 40, and the measurement magnetic field H in the X1 direction reaches the magnetic detection element 10a, allowing the magnetic detection element 10a to measure the strength of the measurement magnetic field H.

[0160] When the current supply to the magnetic state modulation member 20 is stopped and the magnetic state modulation member 20 is in a non-energized state, the magnetization 43m of the spin receptor 43 of the magnetic state variable member 40 is oriented in the Y2 direction due to the influence of the bias magnetic field source 21, as in Example 2-1 shown in FIG. 16A. The magnetization 42m of the magnetically coupled magnetically coupled spin receptor 43 is also oriented in the Y2 direction. This causes the magnetic state variable member 40 to enter a second state in which the effective permeability in the X direction is high. When the variable magnetic field detection unit 100a receives a measurement magnetic field H oriented in the X1 direction in this state, as shown in FIG. 29, a magnetic flux Φ′ oriented in the X1 direction is generated in the magnetically variable member 42, due to the rotation of the magnetization 42m in the XY plane. Therefore, the measurement magnetic field H oriented in the X1 direction is unlikely to reach the magnetic detection element 10a, and the measurement magnetic field H is not substantially measured by the magnetic detection element 10a. The magnetic flux Φ′ is emitted from the X1-side end 421 of the magnetically variable member 42.

[0161] Fig. 30 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) included in a magnetic sensor according to a modified example (Example 2-2M) of Example 2-2, which has a structure similar to that of Example 2-2 but does not include a first magnetic body and a second magnetic body and instead includes a magnetic attraction layer as part of the magnetic state variable member. Fig. 31 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is second state) included in a magnetic sensor according to Example 2-2M.

[0162] In Example 2-2M shown in FIGS. 30 and 31, the free magnetic layer 13, which is the magnetically sensitive portion of the magnetic detector element 10a, and the magnetically inductive layer 42 are magnetically coupled. In FIG. 30, when current is applied to the magnetic state modulating member 20, the magnetization 43m of the spin receptor 43 is oriented in the Y2 direction. As a result, the magnetic state variable member 40, which is magnetically integrated with the magnetically inductive layer 42 and the spin receptor 43, is in a first state in which the effective permeability in the X direction is low. When the magnetic state variable member 40 is in the first state, the magnetization 13m of the free magnetic layer 13 is oriented in the Y2 direction, which is the same as the magnetization 40m of the magnetic state variable member 40. Therefore, as shown in FIG. 30, even when the free magnetic layer 13 receives the measurement magnetic field H, it is not magnetized in that direction, and the measurement magnetic field H is not substantially measured by the magnetic detector element 10a.

[0163] By stopping the current flow to the magnetic state modulation member 20 and setting it to a non-energized state, the magnetization 43m of the spin receptor 43 is oriented in the Y2 direction due to the influence of the bias magnetic field source 21, as in Example 2-2 shown in FIG. 18A. When the variable magnetic field detection unit 100a receives a measurement magnetic field H in this state, as shown in FIG. 31, the magnetization 42m of the magnetically inductive layer 42 rotates in the XY plane along the measurement magnetic field H and becomes oriented in the X1 direction, generating a magnetic flux Φ' oriented in the X1 direction in the magnetically inductive layer 42. The magnetic flux Φ' oriented in the X1 direction also passes through the free magnetic layer 13 magnetically coupled to the magnetic state variable member 40, so that the magnetization 13m of the free magnetic layer 13 is aligned with the magnetic flux Φ' and oriented in the X1 direction. Therefore, the magnetic detection element 10a measures a measurement magnetic flux Φ, which is a magnetic flux based on the measurement magnetic field H. The magnetic flux Φ' inside the magnetically inductive layer 42 is emitted from the end 421 on the X1 side.

[0164] Fig. 32 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) included in a magnetic sensor according to a modified example (Example 3-1M) of Example 3-1, which has a structure similar to that of Example 3-1 but does not include a first magnetic body and a second magnetic body and instead includes a magnetic attraction layer as part of the magnetic state variable member. Fig. 33 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is second state) included in a magnetic sensor according to Example 3-1M.

[0165] 32 and 33, the variable magnetic field detecting unit 100a according to Example 3-1M differs from the variable magnetic field detecting unit 100a according to Example 3-1 (see FIG. 19A, etc.) in that the first magnetic body 31 and the second magnetic body 32 are not provided, and that a magnetically inducing layer 42 is disposed between the non-magnetic member 41 and the magnetic state variable member 40. As shown in FIG. 32, when the magnetization 43m of the spin receptor 43 is oriented in the Z1 direction by applying current to the magnetic state modulation member 20, the magnetization 42m of the magnetically inducing layer 42 is oriented in the Z1 direction along the direction of the magnetization 43m. As a result, the magnetic state variable member 40, which is magnetically integrated and consists of the magnetic attraction layer 42 and the spin receptor 43, enters the first state in which the effective permeability in the X direction is low, so that the measurement magnetic field H in the X1 direction does not concentrate on the magnetic state variable member 40, and the measurement magnetic field H in the X1 direction reaches the magnetic detection element 10a, allowing the magnetic detection element 10a to measure the strength of the measurement magnetic field H.

[0166] When the current supply to the magnetic state modulation member 20 is stopped and the magnetic state modulation member 20 is in a non-energized state, the magnetization 43m of the spin receptor 43 of the magnetic state variable member 40 is oriented in the Y2 direction due to the influence of the bias magnetic field source 21, as in Example 3-1 shown in FIG. 20A. The magnetization 42m of the magnetically coupled magnetically coupled spin receptor 43 is also oriented in the Y2 direction. As a result, the magnetic state variable member 40 enters a second state in which the effective permeability in the X direction is high. When the variable magnetic field detection unit 100a receives a measurement magnetic field H in this state, as shown in FIG. 33, a magnetic flux Φ′ oriented in the X1 direction is generated in the magnetically variable layer 42, due to the rotation of the magnetization 42m in the XY plane. Therefore, the measurement magnetic field H oriented in the X1 direction is unlikely to reach the magnetic detection element 10a, and the measurement magnetic field H is not substantially measured by the magnetic detection element 10a. The magnetic flux Φ′ is emitted from the X1-side end 421 of the magnetically variable layer 42.

[0167] Fig. 34 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is first state) included in a magnetic sensor according to a modified example (Example 3-2M) of Example 3-2, which has a structure similar to that of Example 3-2 but does not include a first magnetic body and a second magnetic body and instead includes a magnetic attraction layer as part of the magnetic state variable member. Fig. 35 is a diagram illustrating a state in which a measurement magnetic field is applied to a magnetic state variable member (magnetic state is second state) included in a magnetic sensor according to Example 3-2M.

[0168] In Example 3-2M shown in FIGS. 34 and 35, the free magnetic layer 13 and the magnetically inductive layer 42, which are the magnetically sensitive portions of the magnetic detector element 10a, are magnetically coupled. In FIG. 34, when current is applied to the magnetic state modulating member 20, the magnetization 43m of the spin receptor 43 is oriented in the Z1 direction. As a result, the magnetic state variable member 40, which is magnetically integrated with the magnetically inductive layer 42 and the spin receptor 43, is in a first state in which the effective permeability in the X direction is low. When the magnetic state variable member 40 is in the first state, the magnetization 13m of the free magnetic layer 13 is oriented in the Z1 direction, which is the same as the magnetization 40m of the magnetic state variable member 40. Therefore, as shown in FIG. 34, even when the free magnetic layer 13 receives the measurement magnetic field H, it is not magnetized along that direction, and the measurement magnetic field H is not substantially measured by the magnetic detector element 10a.

[0169] By stopping the current supply to the magnetic state modulating member 20 and setting it to a non-energized state, the magnetization 43m of the spin receptor 43 is oriented in the Y2 direction due to the influence of the bias magnetic field source 21, as in Example 3-2 shown in FIG. 22A. When the variable magnetic field detection unit 100a receives a measurement magnetic field H in this state, the magnetization 42m of the magnetically inductive layer 42 is oriented in the X1 direction along the measurement magnetic field H, as shown in FIG. 35. As a result, the magnetically integrated magnetic state modulating member 40, consisting of the magnetically inductive layer 42 and the spin receptor 43, enters a second state in which the effective permeability in the X direction is high. Therefore, a magnetic flux Φ' oriented in the X1 direction is generated in the magnetically inductive layer 42, including the rotation of the magnetization 42m in the XY plane. The magnetic flux Φ' oriented in the X1 direction also passes through the free magnetic layer 13, which is magnetically coupled to the magnetically inductive layer 42. Therefore, the magnetization 13m of the free magnetic layer 13 is oriented in the X1 direction along the magnetic flux Φ'. Therefore, the magnetic detector 10a measures a magnetic flux Φ' that is a magnetic flux based on the measurement magnetic field H. The magnetic flux Φ' is emitted from the end 421 of the magnetic induction layer 42 on the X1 side.

[0170] In the above description, in Examples 1-1M, 1-2M, 2-1M, 2-2M, 3-1M, and 3-2M, the first magnetic body 31 and the second magnetic body 32 are not provided, but this is not limited thereto, and one or both of the first magnetic body 31 and the second magnetic body 32 may be provided. In that case, the external magnetic field that affects the magnetically inducing layer 42 becomes the measured magnetic flux Φ instead of the measured magnetic field H, and the magnetic flux Φ' may include the measured magnetic flux Φ and the magnetization 42m of the magnetically inducing layer 42.

[0171] Fig. 36 is a diagram illustrating a state in which the magnetic state variable member is in the second state and a measurement magnetic field has not yet been applied in a magnetic sensor according to Example 2-1m, which is another modification of Example 2-1. Fig. 37 is a diagram illustrating a state in which the magnetic state variable member is in the second state and a measurement magnetic field has been applied in a magnetic sensor according to Example 2-1m, which is another modification of Example 2-1. Fig. 38 is a diagram illustrating a state in which the magnetic state variable member is in the second state and a measurement magnetic field has not yet been applied in a magnetic sensor according to Example 2-2m, which is another modification of Example 2-2. Fig. 39 is a diagram illustrating a state in which the magnetic state variable member is in the second state and a measurement magnetic field has been applied in a magnetic sensor according to Example 2-2m, which is another modification of Example 2-2.

[0172] In Example 2-1, as shown in Fig. 15A, by passing a current through the magnetic state modulation member 20 in the X1 direction, the magnetic state variable member 40 is set to a first state in which the effective magnetic permeability in the X direction is relatively low. Also, as shown in Fig. 16A, by not passing a current through the magnetic state modulation member 20 and setting it to a non-energized state, the magnetization 40m of the magnetic state variable member 40 is weakly oriented in the Y2 direction based on the magnetic field 21m of the bias magnetic field source 21, and the magnetic state variable member 40 is set to a second state in which the effective magnetic permeability in the X direction is relatively high.

[0173] In contrast, Example 2-1m differs from Example 2-1 in the control for the second state. As shown in FIG. 36, by passing current through the magnetic state modulating member 20 in the X2 direction, which is the opposite direction to that in the first state, magnetization 40ma is generated in the Y1 direction, which is the opposite direction to that in the first state of Example 2-1. This magnetization 40ma cancels out the Y2-oriented magnetization 40mb based on the magnetic field 21m of the bias magnetic field source 21, so the magnetization 40m of the magnetic state variable member 40 in the second state becomes particularly weak. This makes the magnetic state variable member 40 in the second state more susceptible to the influence of the measurement magnetic flux Φ. Therefore, as shown in FIG. 37, the direction of the magnetization 40m is in the X1 direction, which is along the measurement magnetic flux Φ, causing the measurement magnetic flux Φ to concentrate on the magnetic state variable member 40.

[0174] In Example 2-2m, as in Example 2-1m, as shown in Fig. 38, current is passed through the magnetic state modulating member 20 in the X2 direction, which is the opposite direction to that in the first state (see Fig. 17A), thereby generating magnetization 40ma in the Y1 direction, which is the opposite direction to that in the first state of Example 2-1. This magnetization 40ma cancels out the magnetization 40mb in the Y2 direction based on the magnetic field 21m of the bias magnetic field source 21, so that the magnetization 40m of the magnetic state variable member 40 in the second state becomes particularly weak, and the magnetic state variable member 40 in the second state becomes more susceptible to the influence of the measurement magnetic flux Φ. Therefore, as shown in Fig. 39, the direction of magnetization 40m is in the X1 direction, along with the measurement magnetic flux Φ, causing the measurement magnetic flux Φ to concentrate on the magnetic state variable member 40.

[0175] When the bias magnetic field source 21 is a permanent magnet or a coil that generates an induced magnetic field when energized, the positional relationship between the bias magnetic field source 21 and the magnetic state variable member 40 is arbitrary. For example, as shown in FIG. 15A, the bias magnetic field source 21 may be arranged along the alignment direction (Z direction, second direction) of the magnetic detector element 10a and the magnetic state variable member 40, or may be arranged in a direction having an in-plane component of the XY plane (first plane). One specific example of such a case is shown in FIG. 40. FIG. 40 is an explanatory diagram of a modified example of the variable magnetic field detector according to Example 2-1.

[0176] Unlike the variable magnetic field detector 100a shown in FIG. 15A, the variable magnetic field detector 100a shown in FIG. 40 does not have a bias magnetic field source 21 on the Z2 side of the magnetic control element 60. In the variable magnetic field detector 100a, the magnetic control element 60, which has a magnetic state modulation member 20 (not shown) and a magnetic state changeable member 40 (not shown), has a longer length in the Y direction, which is one of the in-plane directions of the XY plane (first surface), than in other directions. Therefore, due to shape magnetic anisotropy, the magnetic state changeable member 40 (not shown) has an easy magnetization direction in the Y direction. Like the magnetic state changeable member 40 (not shown), the free magnetic layer 13 (not shown) of the magnetic detector element 10a also has an easy magnetization direction in the Y direction due to shape magnetic anisotropy. This shape magnetic anisotropy can also be considered a bias magnetic field source. If the magnetic state changeable member 40 (not shown) has magnetocrystalline anisotropy, this magnetic anisotropy can also serve as the bias magnetic field source 21. 40, bias magnetic field sources 211 and 212 having permanent magnets or coils that generate an induction magnetic field are provided on both sides of the magnetic control body 60 in the Y direction, and generate magnetic fields 211m and 212m in the Y2 direction, respectively. These magnetic fields cause the magnetization 40m of the magnetic state variable member 40 (not shown) to be oriented in the Y2 direction.

[0177] The present invention includes the following aspects. (1) A magnetic sensor characterized by comprising a variable magnetic field detection unit having a magnetic detection element having a magnetically sensitive portion whose sensitivity axis is aligned with a first direction, a magnetic state variable member that can take a first state and a second state in which the magnetic state including at least one of the effective magnetic permeability and the magnetization direction is different, and a magnetic state modulation member that changes the magnetic state of the magnetic state variable member. (2) A magnetic sensor as described in (1) above, wherein the magnetic detector element has different measurement sensitivity to the measured magnetic field along the first direction when the magnetic state variable member is in the first state and when it is in the second state. (3) The magnetic sensor according to (1), wherein the magnetic detection element and the magnetic state changeable member are aligned in a second direction perpendicular to the first direction. (4) The magnetic sensor according to (3), wherein the length of the magnetic state variable member in the first direction is equal to or greater than the length of the magnetic detector element in the first direction. (5) The magnetic sensor according to (3) above, wherein both ends of the magnetic detector element in the first direction overlap the magnetic state changeable member when viewed in the second direction. (6) The magnetic sensor described in (2) above further includes a magnetic field calculation unit that calculates the measured magnetic field based on a first output from the variable magnetic field detection unit when the magnetic state variable member is in the first state and a second output from the variable magnetic field detection unit when the magnetic state variable member is in the second state. (7) The magnetic sensor described in (1) above, wherein the variable magnetic field detection unit has a non-magnetic member between the magnetic detection element and the magnetic state variable member, and the magnetic sensing unit is magnetically uncoupled from the magnetic state variable member. (8) The magnetic sensor according to (1) above, wherein the magnetic sensing portion is magnetically coupled to the magnetic state changing member. (9) The magnetic sensor according to (8), wherein the magnetic sensing portion and the magnetic state variable member are at least partially integrated. (10) The magnetic sensor described in (2) above, wherein the variable magnetic field detection unit further includes a magnetic body that is magnetized in response to the measurement magnetic field, and the magnetic sensing unit is positioned at a position where it can measure the magnetic flux including the magnetization of the magnetic body. (11) A magnetic sensor as described in (10) above, wherein the magnetic body has a first magnetic body aligned with the magnetic detector element in the first direction, the magnetic detector element is located on one side in the first direction of a first end portion which is an end portion on one side in the first direction of the first magnetic body, and the magnetic state variable member has a portion located on the one side in the first direction of the first end portion of the first magnetic body. (12) The magnetic sensor according to (11), wherein the magnetic detection element and the magnetic state variable member are aligned in a second direction perpendicular to the first direction. (13) The magnetic sensor according to (12), wherein the magnetic state variable member has a portion closer to the first magnetic body in the first direction than the detection center of the magnetic detection element. (14) The magnetic sensor according to (12), wherein the center of the magnetic state variable member in the first direction and the detection center of the magnetic detection element are at the same position in the first direction. (15) The magnetic sensor according to (14), wherein the length of the magnetic state variable member in the first direction is equal to or greater than the length of the magnetic detector element in the first direction. (16) The magnetic sensor according to (12), wherein the first magnetic body has a length in the first direction longer than a length in the second direction. (17) The magnetic sensor according to (12), wherein the magnetic state variable member is arranged so as to be magnetically coupled to the first magnetic body. (18) The magnetic sensor according to (11), wherein the magnetic body further includes a second magnetic body that is distal in the first direction from the first end portion to the magnetic detection element. (19) The magnetic sensor according to (18), wherein the magnetic state variable member is arranged so as to be magnetically coupled to the first magnetic body and the second magnetic body. (20) The magnetic sensor described in (2) above, wherein the magnetic state variable member has a magnetic attraction layer made of a magnetic material, and the magnetic attraction layer and the magnetic detection element are aligned in a second direction perpendicular to the first direction. (21) The magnetic sensor according to (20), wherein the length of the magnetic induction layer in the first direction is equal to or greater than the length of the magnetic detection element in the first direction. (22) The magnetic sensor described in (20) above, wherein the magnetic state variable member has another member aligned with the magnetic attraction layer in the second direction and magnetically coupled to the magnetic attraction layer, and when viewed in the second direction, both ends of the other member in the first direction overlap with the magnetic attraction layer. (23) The magnetic sensor according to (20), wherein the magnetic sensing portion is magnetically coupled to the magnetic state variable member. (24) A magnetic sensor as described in (2) above, wherein the magnetic state modulation element changes the magnetic state of the magnetic state variable element based on a change in the state of current flow, and the state of current flow of the magnetic state modulation element differs when the magnetic state variable element is in the first state and when it is in the second state. (25) A magnetic sensor as described in (24) above, wherein the effective permeability μ2 in the first direction of the magnetic state variable member in the second state is higher than the effective permeability μ1 in the first direction of the magnetic state variable member in the first state. (26) The magnetic sensor described in (25) above, wherein the variable magnetic field detection unit has a bias magnetic field source that aligns the magnetization of the magnetic state variable member in the first state in a transverse direction that intersects the first direction to the extent that the magnetization of the magnetic state variable member does not rotate when the measurement magnetic field is applied, and the magnetization of the magnetic state variable member in the second state is oriented along the in-plane direction of the first surface with a strength that allows it to rotate in the in-plane direction of a first surface that includes the first direction as one of the in-plane directions when the measurement magnetic field is applied. (27) The magnetic sensor according to (26), wherein when the magnetic state variable member is in the first state, the magnetic state modulation member is in a non-conductive state. (28) The magnetic sensor according to (26), wherein when the magnetic state variable member is in the first state, the magnetic state modulation member is in a conducting state. (29) The magnetic sensor according to (26), wherein the intersecting direction is perpendicular to the first direction. (30) The magnetic sensor according to (26), wherein the magnetic state variable member is a film-like body, and the intersecting direction is along the thickness direction of the film-like body. (31) The magnetic sensor according to (26), wherein the magnetic state variable member is a film-like body, and the first surface is parallel to a film surface of the film-like body. (32) The magnetic sensor according to (31), wherein the intersecting direction is an in-plane direction of the film surface of the film body. (33) The magnetic sensor according to (30), wherein the magnetic state modulation member has a film-like shape, and the magnetic state variable member and the magnetic state modulation member are arranged side by side in the intersecting direction. (34) A magnetic sensor as described in (26) above, which is provided with an electromagnetic state variable member that combines the functions of the magnetic state modulation member and the magnetic state variable member in place of the magnetic state modulation member and the magnetic state variable member. (35) The magnetic sensor described in (26) above, wherein the magnetic state modulation element has a spin torque generating unit that imparts a spin orbit torque to the magnetic state variable element when current is applied, and the magnetic state of the magnetic state variable element in the second state is set based on the spin orbit torque from the spin torque generating unit. (36) The magnetic sensor according to (35), wherein the magnetization of the magnetic state variable member in the second state is along the current flow direction of the spin torque generation unit. (37) A magnetic sensor as described in (25) above, wherein the magnetization of the magnetic state variable member in the first state is magnetized by the magnetic state modulating member in a transverse direction intersecting the first direction to an extent that the magnetization does not rotate when the measurement magnetic field is applied, and the magnetization of the magnetic state variable member in the second state is along the in-plane direction of the first surface with an intensity that allows rotation in the in-plane direction of a first surface that includes the first direction as one of the in-plane directions when the measurement magnetic field is applied. (38) A magnetic sensor as described in (37) above, wherein when the magnetic state variable member is in the first state, the magnetic state modulation member is in a conducting state, and when the magnetic state variable member is in the second state, the magnetic state modulation member is in a non-conducting state. (39) A magnetic sensor as described in (37) above, wherein when the magnetic state variable member is in the first state, the magnetic state modulation member is in an energized state, and when the magnetic state variable member is in the second state, the magnetic state modulation member is in an energized state different from that in the first state. (40) The magnetic sensor according to (37), wherein the intersecting direction is perpendicular to the first direction. (41) The magnetic sensor described in (37) above, wherein the variable magnetic field detection unit has a bias magnetic field source that aligns the magnetization of the magnetic state variable member in the in-plane direction of the first surface to such an extent that the magnetization of the magnetic state variable member in the second state rotates when the measurement magnetic field is applied. (42) The magnetic sensor according to (41), wherein the bias magnetic field source causes the magnetization of the magnetic state changeable member to be aligned in a direction different from the intersecting direction and perpendicular to the first direction. (43) The magnetic sensor according to (37), wherein the magnetic state variable member is a film-like body, and the intersecting direction is along the thickness direction of the film-like body. (44) The magnetic sensor according to (37), wherein the magnetic state variable member is a film-like body, and the intersecting direction is an in-plane direction of the film surface of the film-like body. (45) The magnetic sensor according to (37), wherein the magnetic state variable member is a film-like body, and the first surface is parallel to a film surface of the film-like body. (46) The magnetic sensor according to (43), wherein the magnetic state modulation member has a film-like shape, and the magnetic state variable member and the magnetic state modulation member are arranged side by side in the intersecting direction. (47) A magnetic sensor as described in (1) above, which is provided with an electromagnetic state variable member that combines the functions of the magnetic state modulation member and the magnetic state variable member in place of the magnetic state modulation member and the magnetic state variable member. (48) The magnetic sensor according to (47), wherein the electromagnetically conductive state variable member has a portion made of an antiferromagnetic material. (49) A magnetic sensor as described in (47) above, wherein the electromagnetic state variable member has at least one of crystalline magnetic anisotropy and shape magnetic anisotropy, and the magnetic state when the electromagnetic state variable member is not conducting is set based on the crystalline magnetic anisotropy and / or the shape magnetic anisotropy. (50) The magnetic sensor described in (37) above, wherein the magnetic state modulation element has a spin torque generating unit that imparts a spin orbit torque to the magnetic state variable element when current is applied, and the magnetic state of the magnetic state variable element in the first state is set based on the spin orbit torque from the spin torque generating unit. (51) A magnetic sensor as described in (26) or (37) above, wherein the direction of current flow through the magnetic state variable member when the magnetic state variable member is in the second state is along a third direction that is in-plane with the first surface and perpendicular to the first direction. (52) A magnetic sensor as described in (26) or (41) above, wherein the magnetic state modulation member has an antiferromagnetic portion made of antiferromagnetic material, and the exchange coupling between the antiferromagnetic portion and the magnetic state variable member serves as the bias magnetic field source. (53) The magnetic sensor according to (26) or (41), wherein the bias magnetic field source includes at least one of a coil that generates an induced magnetic field when energized, and a permanent magnet. (54) The magnetic sensor described in (53) above, wherein the magnetic state modulation member and the magnetic state variable member form a magnetic control body stacked in a second direction perpendicular to the first direction, the magnetic control body and the magnetic detection element are arranged side by side in the second direction, and the bias magnetic field source may form a stacked structure with the magnetic control body. (55) A magnetic sensor as described in (53) above, wherein the magnetic state modulation member and the magnetic state variable member form a magnetic control body stacked in a second direction perpendicular to the first direction, the magnetic control body and the magnetic detection element are arranged side by side in the second direction, and the bias magnetic field source and the magnetic control body are arranged side by side in a direction having an in-plane component of the first surface. (56) A magnetic sensor as described in (26) or (41) above, wherein the magnetic state variable member has at least one of crystalline magnetic anisotropy and shape magnetic anisotropy, and the crystalline magnetic anisotropy and / or the shape magnetic anisotropy serves as the bias magnetic field source. (57) The magnetic sensor according to (1), wherein the magnetic state variable member has a portion made of an antiferromagnetic material. (58) A magnetic measurement method using a magnetic sensor including a variable magnetic field detection unit having a magnetic detection element having a sensitivity axis along a first direction, a magnetic state variable member that can be in a first state and a second state, the magnetic states of which differ including at least one of effective permeability and magnetization direction, and a magnetic state modulation member that changes the magnetic state of the magnetic state variable member, and a magnetic field calculation unit that calculates a measurement magnetic field along the first direction from a first output from the variable magnetic field detection unit when the magnetic state variable member is in the first state and a second output from the variable magnetic field detection unit when the magnetic state variable member is in the second state, the magnetic measurement method comprising: a first measurement step of obtaining the first output with the magnetic state variable member in the first state when the measurement magnetic field is applied; a second measurement step of obtaining the second output with the magnetic state variable member in the second state when the measurement magnetic field is applied; and a magnetic field calculation step of calculating the measurement magnetic field from the first output and the second output in the magnetic field calculation unit. [Industrial Applicability]

[0178] 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]

[0179] 1: Magnetic sensor 2: Magnetic field detection unit 3: Control power supply 4: Magnetic field calculation section 5: Amplifier 6: A / D conversion circuit 7: Control section 10P: Detection center 10a, 10b, 10c, 10d: magnetic detection elements 11: Fixed magnetic layer 11m, 13m, 40m, 40ma, 40mb, 42m, 43m, 601m: Magnetization 12: Middle class 13: Free magnetic layer (magnetic sensing part) 15: Full bridge circuit 20: Magnetic state modulation member 20af: Exchange coupling 20c, 601c: Current 21, 211, 212: Bias magnetic field source 21m, 211m, 212m: magnetic field 31: First magnetic body 32:Second magnetic material 40: Magnetic state variable member 41: Non-magnetic material 42: Magnetic attraction layer 421: End of the magnetic attraction layer in the first direction 43: Spin receptor 50: Insulator 60: Magnetic control body 61: Control wiring 62: Measurement wiring 601: Electromagnetically variable member 100a, 100b, 100c, 100d: Variable magnetic field detection unit 311: First end GND: Ground terminal H: Measurement magnetic field I: Control current source V: Measurement voltage source V1, V2: Output terminal Vdd: Power supply terminal Φ: measured magnetic flux Φ' :Magnetic flux

Claims

1. a magnetic detection element having a magnetically sensitive portion whose sensitivity axis is aligned with a first direction; a magnetic state variable member that can be in a first state and a second state, the first state and the second state being different magnetic states including at least one of effective magnetic permeability and magnetization direction; a magnetic state modulating member that changes the magnetic state of the magnetic state variable member; A magnetic sensor comprising a variable magnetic field detection unit having a

2. 2. The magnetic sensor according to claim 1, wherein the magnetic detector element has a different measurement sensitivity to the magnetic field along the first direction when the magnetic state variable member is in the first state and when the magnetic state variable member is in the second state.

3. The magnetic sensor according to claim 1 , wherein the magnetic detector element and the magnetic state changeable member are aligned in a second direction perpendicular to the first direction.

4. The magnetic sensor according to claim 3 , wherein the length of the magnetic state variable member in the first direction is equal to or greater than the length of the magnetic detector element in the first direction.

5. The magnetic sensor according to claim 3 , wherein both ends of the magnetic detector element in the first direction overlap the magnetic state changeable member when viewed in the second direction.

6. 3. The magnetic sensor of claim 2, further comprising a magnetic field calculation unit that calculates the measured magnetic field based on a first output from the variable magnetic field detection unit when the magnetic state variable member is in the first state and a second output from the variable magnetic field detection unit when the magnetic state variable member is in the second state.

7. 2. The magnetic sensor according to claim 1, wherein the variable magnetic field detection unit has a non-magnetic member between the magnetic detection element and the magnetic state changeable member, and the magnetic sensing unit is magnetically uncoupled from the magnetic state changeable member.

8. The magnetic sensor according to claim 1 , wherein the magnetic sensing portion is magnetically coupled to the magnetic state changing member.

9. The magnetic sensor according to claim 8 , wherein the magnetic sensing portion and the magnetic state changing member are at least partially integrated.

10. The variable magnetic field detection unit further includes a magnetic body that is magnetized by receiving the measurement magnetic field, The magnetic sensor according to claim 2 , wherein the magnetic sensing portion is disposed at a position where it can measure a magnetic flux including the magnetization of the magnetic body.

11. the magnetic body includes a first magnetic body aligned with the magnetic detection element in the first direction, the magnetic detection element is located on the one side in the first direction relative to a first end portion of the first magnetic body, the first end portion being an end portion on one side in the first direction; The magnetic sensor according to claim 10 , wherein the magnetic state variable member has a portion located on the one side in the first direction relative to the first end of the first magnetic body.

12. The magnetic sensor according to claim 11 , wherein the magnetic detector element and the magnetic state changeable member are aligned in a second direction perpendicular to the first direction.

13. The magnetic sensor according to claim 12 , wherein the magnetic state changing member has a portion that is closer to the first magnetic body in the first direction than a detection center of the magnetic detection element.

14. The magnetic sensor according to claim 12 , wherein the center of the magnetic state changeable member in the first direction and the detection center of the magnetic detection element are at the same position in the first direction.

15. The magnetic sensor according to claim 14 , wherein the length of the magnetic state changeable member in the first direction is equal to or greater than the length of the magnetic detector element in the first direction.

16. The magnetic sensor according to claim 12 , wherein the first magnetic body has a length in the first direction longer than a length in the second direction.

17. The magnetic sensor according to claim 12 , wherein the magnetic state changeable member is arranged so as to be magnetically coupled to the first magnetic body.

18. The magnetic sensor according to claim 11 , wherein the magnetic body further includes a second magnetic body that is more distal in the first direction than the magnetic detection element when viewed from the first end.

19. The magnetic sensor according to claim 18 , wherein the magnetic state changeable member is arranged so as to be magnetically coupled to the first magnetic body and the second magnetic body.

20. the magnetic state changeable member has a magnetic attraction layer made of a magnetic material; The magnetic sensor of claim 2 , wherein the magnetic induction layer and the magnetic sensing element are aligned in a second direction perpendicular to the first direction.

21. The magnetic sensor of claim 20 , wherein the length of the magnetic attraction layer in the first direction is equal to or greater than the length of the magnetic sensing element in the first direction.

22. the magnetic state changeable member has another member aligned with the magnetic attraction layer in the second direction and magnetically coupled to the magnetic attraction layer; The magnetic sensor according to claim 20 , wherein both ends of the other member in the first direction overlap the magnetic attraction layer when viewed in the second direction.

23. The magnetic sensor according to claim 20 , wherein the magnetic sensing portion is magnetically coupled to the magnetic state changing member.

24. the magnetic state modulating member changes the magnetic state of the magnetic state variable member based on a change in a state of current flow; 3. The magnetic sensor according to claim 2, wherein the magnetic state modulating member is in a different state of current flow when the magnetic state modulating member is in the first state from when the magnetic state modulating member is in the second state.

25. 25. The magnetic sensor of claim 24, wherein the effective permeability μ2 in the first direction of the magnetic state changeable member in the second state is higher than the effective permeability μ1 in the first direction of the magnetic state changeable member in the first state.

26. the variable magnetic field detection unit has a bias magnetic field source that aligns the magnetization of the magnetic state changeable member in an intersecting direction that intersects with the first direction to such an extent that the magnetization of the magnetic state changeable member in the first state does not rotate when the measurement magnetic field is applied, 26. The magnetic sensor of claim 25, wherein the magnetization of the magnetic state variable member in the second state is oriented along an in-plane direction of the first surface with a strength sufficient to allow rotation in an in-plane direction of the first surface, the in-plane direction including the first direction as one of the in-plane directions, when the measurement magnetic field is applied.

27. 27. The magnetic sensor of claim 26, wherein when the magnetic state alterable member is in the first state, the magnetic state modulating member is in a non-conductive state.

28. 27. The magnetic sensor of claim 26, wherein the magnetic state modulating member is in an energized state when the magnetic state alterable member is in the first state.

29. The magnetic sensor of claim 26 , wherein the cross direction is orthogonal to the first direction.

30. 27. The magnetic sensor according to claim 26, wherein the magnetic state variable member is a film-like body, and the intersecting direction is along the thickness direction of the film-like body.

31. 27. The magnetic sensor according to claim 26, wherein the magnetic state variable member is a film-like body, and the first surface is parallel to a film surface of the film-like body.

32. 32. The magnetic sensor according to claim 31, wherein the intersecting direction is an in-plane direction of the film surface of the film body.

33. 31. The magnetic sensor according to claim 30, wherein the magnetic state modulation member has a film-like shape, and the magnetic state variable member and the magnetic state modulation member are arranged side by side in the intersecting direction.

34. 27. The magnetic sensor according to claim 26, further comprising an electromagnetically conductive member having both the functions of the magnetic state modulation member and the magnetic state variable member in place of the magnetic state modulation member and the magnetic state variable member.

35. the magnetic state modulation member has a spin torque generation unit that applies a spin orbit torque to the magnetic state variable member when current is applied; 27. The magnetic sensor according to claim 26, wherein the magnetic state of the magnetic state variable member in the second state is set based on the spin-orbit torque from the spin torque generator.

36. 36. The magnetic sensor according to claim 35, wherein the magnetization of the magnetic state changeable member in the second state is aligned with a current-carrying direction of the spin torque generation unit.

37. the magnetization of the magnetic state variable member in the first state is magnetized by the magnetic state modulating member in a direction intersecting the first direction to such an extent that the magnetization does not rotate when the measurement magnetic field is applied, 26. The magnetic sensor of claim 25, wherein the magnetization of the magnetic state variable member in the second state is oriented along an in-plane direction of the first surface with a strength sufficient to allow rotation in an in-plane direction of the first surface, the in-plane direction including the first direction as one of the in-plane directions, when the measurement magnetic field is applied.

38. 38. The magnetic sensor of claim 37, wherein when the magnetic state variable member is in the first state, the magnetic state modulation member is in a conducting state, and when the magnetic state variable member is in the second state, the magnetic state modulation member is in a non-conducting state.

39. 38. The magnetic sensor of claim 37, wherein when the magnetic state variable member is in the first state, the magnetic state modulation member is in a conducting state, and when the magnetic state variable member is in the second state, the magnetic state modulation member is in a conducting state different from that in the first state.

40. 38. The magnetic sensor of claim 37, wherein the cross direction is orthogonal to the first direction.

41. 38. The magnetic sensor of claim 37, wherein the variable magnetic field detection unit has a bias magnetic field source that aligns the magnetization of the magnetic state variable member in an in-plane direction of the first surface to such an extent that the magnetization of the magnetic state variable member in the second state rotates when the measurement magnetic field is applied.

42. 42. The magnetic sensor of claim 41, wherein the bias magnetic field source causes the magnetization of the magnetic state changeable member to be along a direction different from the transverse direction and perpendicular to the first direction.

43. 38. The magnetic sensor according to claim 37, wherein the magnetic state variable member is a film-like body, and the intersecting direction is along the thickness direction of the film-like body.

44. 38. The magnetic sensor according to claim 37, wherein the magnetic state variable member is a film-like body, and the intersecting direction is an in-plane direction of a film surface of the film-like body.

45. 38. The magnetic sensor according to claim 37, wherein the magnetic state variable member is a film-like body, and the first surface is parallel to a film surface of the film-like body.

46. 44. The magnetic sensor according to claim 43, wherein the magnetic state modulation member has a film-like shape, and the magnetic state variable member and the magnetic state modulation member are arranged side by side in the intersecting direction.

47. 2. The magnetic sensor according to claim 1, further comprising an electromagnetically conductive member having both the functions of the magnetic state modulation member and the magnetic state variable member in place of the magnetic state modulation member and the magnetic state variable member.

48. 48. The magnetic sensor according to claim 47, wherein the electromagnetically conductive member has a portion made of an antiferromagnetic material.

49. 48. The magnetic sensor of claim 47, wherein the electromagnetic state variable member has at least one of crystalline magnetic anisotropy and shape magnetic anisotropy, and the magnetic state when the electromagnetic state variable member is not conducting is set based on the crystalline magnetic anisotropy and / or the shape magnetic anisotropy.

50. the magnetic state modulation member has a spin torque generation unit that applies a spin orbit torque to the magnetic state variable member when current is applied; 38. The magnetic sensor according to claim 37, wherein the magnetic state of the magnetic state variable member in the first state is set based on the spin-orbit torque from the spin torque generator.

51. 38. The magnetic sensor of claim 26 or 37, wherein the direction of current flow through the magnetic state changeable member when the magnetic state changeable member is in the second state is along a third direction that is an in-plane direction of the first surface and perpendicular to the first direction.

52. 42. The magnetic sensor according to claim 26 or claim 41, wherein the magnetic state modulating member has an antiferromagnetic portion made of antiferromagnetic material, and exchange coupling between the antiferromagnetic portion and the magnetic state variable member serves as the bias magnetic field source.

53. 42. The magnetic sensor according to claim 26 or claim 41, wherein the bias magnetic field source includes at least one of a coil that generates an induced magnetic field when current is passed through it, and a permanent magnet.

54. the magnetic state modulation member and the magnetic state changeable member constitute a magnetic control body stacked in a second direction perpendicular to the first direction, and the magnetic control body and the magnetic detection element are arranged side by side in the second direction, 54. The magnetic sensor of claim 53, wherein the bias magnetic field source may form a laminated structure with the magnetic control element.

55. the magnetic state modulation member and the magnetic state changeable member constitute a magnetic control body stacked in a second direction perpendicular to the first direction, and the magnetic control body and the magnetic detection element are arranged along the second direction; 54. The magnetic sensor according to claim 53, wherein the bias magnetic field source and the magnetic control element are aligned in a direction having a component in an in-plane direction of the first surface.

56. 42. The magnetic sensor according to claim 26, wherein the magnetic state variable member has at least one of magnetocrystalline anisotropy and shape magnetic anisotropy, and the magnetocrystalline anisotropy and / or the shape magnetic anisotropy serves as the bias magnetic field source.

57. 2. The magnetic sensor according to claim 1, wherein the magnetic state variable member has a portion made of an antiferromagnetic material.

58. a magnetic sensing element having a sensitivity axis along a first direction; a magnetic state variable member that can be in a first state and a second state, the first state and the second state being different magnetic states including at least one of effective magnetic permeability and magnetization direction; a magnetic state modulating member that changes the magnetic state of the magnetic state variable member; a variable magnetic field detection unit having a magnetic field calculation unit that calculates a measured magnetic field along the first direction from a first output from the variable magnetic field detection unit when the magnetic state variable member is in the first state and a second output from the variable magnetic field detection unit when the magnetic state variable member is in the second state. A magnetic measurement method using a magnetic sensor comprising: a first measurement step of setting the magnetic state variable member to the first state and obtaining the first output while the measurement magnetic field is applied; a second measuring step of setting the magnetic state variable member to the second state and obtaining the second output while the measurement magnetic field is being applied; 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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