Magnetic sensor and magnetic measurement method

Abstract

A magnetic sensor 1 according to the present invention is capable of measuring a small magnetic field with high accuracy by removing 1 / f noise, and comprises a variable magnetic field detection unit 100a which includes: a magnetic detection element 10a including a magnetic sensitive part having a sensitivity axis along a first direction (X direction); an anisotropy variable layer 40 having a portion which is made of a ferromagnetic material and being capable of taking a first state or a second state that have different magnetic states including at least one of effective magnetic permeability and magnetization direction; and a spin Hall layer 20 for varying the magnetic state of the anisotropy variable layer 40. The magnetic detection element 10a may have different measurement sensitivities to a measurement magnetic field along the first direction between when the anisotropy variable layer 40 is in the first state and when the anisotropy variable layer 40 is in the second state.

Description

Magnetic Sensor and Magnetic Measurement Method

[0001] The present invention relates to a magnetic sensor provided with a magnetoresistive effect element and a magnetic measurement method.

[0002] As a magnetic sensor for detecting and measuring a magnetic field, there is one provided with a magnetoresistive effect element using a GMR (giant magnetoresistance) effect or a TMR (tunnel magnetoresistance) effect. The magnetoresistive effect element in these magnetic sensors has a structure in which a fixed magnetic layer, a non-magnetic intermediate layer, and a free magnetic layer are laminated in this order. In the magnetoresistive effect element, when an external magnetic field to be measured is applied, the magnetization direction of the free magnetic layer changes, and a resistance change corresponding to the angle formed by the magnetization direction of the free magnetic layer and the magnetization direction of the fixed magnetic layer occurs. A magnetic sensor provided with a magnetoresistive effect element can detect a magnetic field by using the resistance change of the magnetoresistive effect element.

[0003] A magnetic sensor provided with a magnetoresistive effect element has 1 / f noise that cannot be removed by a filter. Since 1 / f noise is inversely proportional to the frequency and increases as the frequency decreases, it may become an inhibiting factor when performing high-precision measurement. For this reason, various methods are used to remove 1 / f noise.

[0004] Patent Document 1 discloses a 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) in an even-function type magnetic sensor.

[0005] Patent Document 2 discloses a measuring device that removes noise due to a Schottky barrier generated between an electrode and a sample when measuring the Hall electromotive force of a semiconductor sample. By shifting the frequency band of the voltage difference Vm to the low-frequency side, the frequency band of the voltage difference Vm that is greatly affected by 1 / f noise is removed.

[0006] Patent Document 3 discloses a magnetic field sensing device that samples a bridge signal with each of a first current and a second current by switching two sample holds, and determines the value of a 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 polarity of the sensor signal and takes the difference between the modulated signals in order to remove 1 / f noise from the output signal.

[0008] Japanese Patent Publication No. 2018-115972, Japanese Patent Publication No. 2020-148727, Japanese Patent Publication No. 2012-518788, Japanese Patent Publication No. 2009-544004

[0009] Magnetic sensors equipped with magnetoresistive elements have a problem in which 1 / f noise in the low-frequency range reduces the detection accuracy of the magnetic sensor. Various devices and methods have been proposed to solve this problem. The present invention aims to provide a magnetic sensor equipped with a magnetoresistive element and a magnetic measurement method that can remove 1 / f noise with a configuration different from conventional ones and measure small magnetic fields with high accuracy.

[0010] In one embodiment, the present invention is a magnetic sensor comprising a magnetic sensing element having a magnetosensitive portion whose sensitivity axis is aligned along a first direction; an anisotropic variable layer having a portion made of a ferromagnetic material and capable of taking on a first state and a second state in which the magnetic state differs, including at least one of the effective permeability and the direction of magnetization; and a spin Hall layer that changes the magnetic state of the anisotropic variable layer.

[0011] In the above-described magnetic sensor, it is preferable that the magnetic sensing element has different measurement sensitivity for the measurement magnetic field along the first direction when the anisotropic variable layer is in the first state and when it is in the second state. By using the two outputs from the magnetic field detection unit when the anisotropic variable layer 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 sensing element and the anisotropic variable layer of the above-described magnetic sensor may be aligned in a second direction perpendicular to the first direction. In this case, the length of the anisotropic variable layer in the first direction may be greater than or equal to the length of the magnetic sensing element in the first direction, and when viewed in the second direction, both ends of the magnetic sensing element in the first direction may overlap with the anisotropic variable layer.

[0013] The magnetic sensor described above 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 anisotropic variable layer is in the first state and a second output from the variable magnetic field detection unit when the anisotropic variable layer is in the second state. The magnetic field calculation unit can calculate a signal from which 1 / f noise has been removed.

[0014] In one embodiment of the magnetic sensor described above (the first embodiment), the variable magnetic field detection unit may have a non-magnetic member between the magnetic detection element and the anisotropic variable layer, and the magnetosensitive unit may be magnetically uncoupled to the anisotropic variable layer. When the magnetosensitive unit of the magnetic detection element and the anisotropic variable layer are magnetically uncoupled, in the second state in which the anisotropic variable layer becomes more efficient at collecting the magnetic flux based on the measurement magnetic field, the magnetic flux based on the measurement magnetic field becomes less likely to reach the magnetosensitive unit of the magnetic detection element.

[0015] In another embodiment of the magnetic sensor described above (the second embodiment), the magnetosensitive portion may be magnetically coupled to the anisotropic variable layer. When the magnetosensitive portion of the magnetic sensing element and the anisotropic variable layer are magnetically coupled, in the second state in which the anisotropic variable layer is more efficient at collecting the magnetic flux based on the measurement magnetic field, the magnetic flux based on the measurement magnetic field is also more easily able to reach the magnetosensitive portion of the magnetic sensing element.

[0016] In the magnetic sensor according to the second embodiment described above, the magnetic sensing portion and the anisotropic variable layer may be integrated in at least a portion of the same area.

[0017] The variable magnetic field detection unit of the above-described magnetic sensor may further include a magnetic material that is magnetized upon receiving the measurement magnetic field, and the magnetosensitive unit may be positioned at a location where the magnetic flux including the magnetization of the magnetic material can be measured. The magnetization of the magnetic material increases the magnetic flux density reaching the magnetosensitive unit, enabling highly accurate measurement.

[0018] The magnetic material may have a first magnetic material aligned with the magnetic sensing element in the first direction. In this case, the magnetic sensing element is located on one side of the first direction from the first end of the first magnetic material, and the anisotropic variable layer may have a portion located on one side of the first direction from the first end of the first magnetic material. In this case, the magnetic sensing element and the anisotropic variable layer may be aligned in a second direction perpendicular to the first direction. Furthermore, the anisotropic variable layer may have a portion that is closer to the first magnetic material in the first direction than the detection center of the magnetic sensing element. Alternatively, the center of the anisotropic variable layer in the first direction and the detection center of the magnetic sensing element may be at the same position in the first direction. In this case, the length of the anisotropic variable layer in the first direction may be greater than or equal to the length of the magnetic sensing element in the first direction.

[0019] When the magnetic sensing element and the anisotropic variable layer are aligned in the second direction, the length of the first magnetic material in the first direction may be longer than the length in the second direction. Alternatively, the anisotropic variable layer may be arranged to be magnetically coupled to the first magnetic material. In this case, when the effective permeability of the anisotropic variable layer is high, the magnetic flux including the magnetization generated in the first magnetic material is guided almost directly to the anisotropic variable layer, making it difficult for the magnetic flux to reach regions other than the anisotropic variable layer.

[0020] The magnetic material may further include not only a first magnetic material, but also a second magnetic material that is distal to the magnetic sensing element in the first direction when viewed from the first end. By positioning the magnetic sensing element between the first magnetic material and the second magnetic material in the first direction, the magnetic flux based on the measurement magnetic field can be efficiently delivered to the magnetic sensing element.

[0021] In this case, the anisotropic variable layer may be arranged to be magnetically coupled with the first magnetic material and the second magnetic material. In this case, the measurement magnetic field preferentially passes through the portion consisting of the first magnetic material, the anisotropic variable layer, and the second magnetic material that are magnetically coupled, so the difference in magnetic flux density reaching the magnetic sensing part of the magnetic sensing element can be increased compared to when the anisotropic variable layer is not magnetically coupled with the first magnetic material or the second magnetic material.

[0022] In cases where the measurement sensitivity differs between the first state and the second state, the spin Hall layer may change the magnetic state of the anisotropic variable layer based on the change in the energizing state, and the energizing state of the spin Hall layer may differ when the anisotropic variable layer is in the first state and when it is in the second state. By changing the energizing state of the spin Hall layer, the measurement sensitivity can be made to differ between the first state and the second state. As a specific example in this case, the effective permeability μ2 in the first direction of the anisotropic variable layer in the second state may be higher than the effective permeability μ1 in the first direction of the anisotropic variable layer in the first state.

[0023] As a specific example (Type A) of the case where the effective permeability of the anisotropic variable layer in the first direction has the above relationship in the first state and the second state, the variable magnetic field detection unit may have a bias magnetic field source that causes the magnetization of the anisotropic variable layer in the first state to be aligned with an intersecting direction intersecting the first direction to such an extent that the magnetization of the anisotropic variable layer in the first state does not rotate when the measurement magnetic field is applied, and the magnetization of the anisotropic variable layer in the second state may be aligned with the in-plane direction of the first plane to such an extent that it can rotate in the in-plane direction of the first plane, which includes the first direction as one of the in-plane directions, when the measurement magnetic field is applied.

[0024] In a type A magnetic sensor, when the anisotropic variable layer is in the first state, the spin Hall layer may be in a non-energized state or in an energized state.

[0025] In a magnetic sensor of type A, the intersection direction may be perpendicular to the first direction.

[0026] In a type A magnetic sensor, the anisotropic variable layer is a film-like body, and the intersecting direction may be aligned with the thickness direction of the film-like body. In this case, the spin Hall layer has a film-like shape, and the anisotropic variable layer and the spin Hall layer may be arranged side by side in the intersecting direction.

[0027] In a type A magnetic sensor, the anisotropic variable layer may be a film-like body, and the first surface may be parallel to the film surface of the film-like body. In this case, the intersecting direction may be the in-plane direction of the film surface of the film-like body.

[0028] In a type A magnetic sensor, the spin Hall layer may have a spin torque generating unit that applies a spin orbit torque to the anisotropic variable layer when energized. In this case, the magnetic state of the anisotropic variable layer in the second state may be set based on the spin orbit torque from the spin torque generating unit. In this case, the magnetization of the anisotropic variable layer in the second state may be along the direction of energization of the spin torque generating unit.

[0029] As another specific example (Type B, Type C) of the case where the effective permeability of the anisotropic variable layer in the first direction has the above relationship in the first and second states, the magnetization of the anisotropic variable layer in the first state may be magnetized in a crossing direction intersecting the first direction by the spin Hall layer to such an extent that the magnetization does not rotate when the measurement magnetic field is applied. In this case, the magnetization of the anisotropic variable layer in the second state may be aligned with the in-plane direction of the first plane to such an extent that it can rotate in the in-plane direction of the first plane, which includes the first direction as one of the in-plane directions, when the measurement magnetic field is applied.

[0030] In a type B or type C magnetic sensor, when the anisotropic variable layer is in the first state, the spin Hall layer is energized, and when the anisotropic variable layer is in the second state, the spin Hall layer may be de-energized.

[0031] In a type B magnetic sensor, when the anisotropic variable layer is in the first state, the spin Hall layer is energized, and when the anisotropic variable layer is in the second state, the spin Hall layer may be energized in a different state than in the first state.

[0032] In a Type B or Type C magnetic sensor, the crossing direction may be perpendicular to the first direction.

[0033] In a Type B or Type C magnetic sensor, the variable magnetic field detection unit may have a bias magnetic field source that causes the magnetization of the anisotropic variable layer in the second state to rotate when the measuring magnetic field is applied, so as to align with the in-plane direction of the first surface. In this case, the bias magnetic field source may cause the magnetization of the anisotropic variable layer to align with a direction different from the crossing direction and perpendicular to the first direction.

[0034] In a Type C magnetic sensor, the anisotropic variable layer may be a film-like body, in which case the crossing direction may be along the thickness direction of the film-like body. In this case, the spin Hall layer has a film-like shape, and the anisotropic variable layer and the spin Hall layer may be arranged side by side in the crossing direction.

[0035] In a type B or type C magnetic sensor, the anisotropic variable layer is a film-like body, and the intersecting direction may be the in-plane direction of the film surface of the film-like body.

[0036] In a type B magnetic sensor, the anisotropic variable layer may be a film-like body, and the first surface may be parallel to the film surface of the film-like body.

[0037] In a Type B or Type C magnetic sensor, the spin Hall layer may have a spin torque generating unit that applies a spin orbit torque to the anisotropic variable layer when energized, in which case the magnetic state in the first state of the anisotropic variable layer may be set based on the spin orbit torque from the spin torque generating unit.

[0038] In the magnetic sensor of type A, type B, or type C described above, when the anisotropy variable layer is in the second state, the current conduction direction of the anisotropy variable layer may be along a third direction that is in the in-plane direction of the first surface and orthogonal to the first direction.

[0039] In the magnetic sensor having the bias magnetic field source described above, the anisotropy variable layer may have a portion made of a material having crystalline magnetic anisotropy, and the magnetization based on the crystalline magnetic anisotropy may serve as the bias magnetic field source.

[0040] In the magnetic sensor having the bias magnetic field source described above, the anisotropy variable layer may have shape magnetic anisotropy, and the magnetization based on the crystalline magnetic anisotropy may serve as the bias magnetic field source.

[0041] In the magnetic sensor described above, when the spin hall layer is in a non-current-conducting state, the anisotropy variable layer may be magnetized in a predetermined direction by residual magnetization.

[0042] In the magnetic sensor having the bias magnetic field source described above, the anisotropy variable layer may have a portion made of an antiferromagnet, and the exchange coupling interaction between the portion made of a ferromagnet and the portion made of the antiferromagnet may serve as the bias magnetic field source.

[0043] In the magnetic sensor having the bias magnetic field source described above, the spin hall layer may have an antiferromagnetic portion made of an antiferromagnet, and the exchange coupling between the antiferromagnetic portion and the anisotropy variable layer may serve as the bias magnetic field source. In this case, the spin hall layer may have a portion made of a material capable of generating a spin orbit torque and a portion made of an antiferromagnet capable of having an exchange coupling interaction with the anisotropy variable layer, or the spin hall layer may have a portion made of an antiferromagnet capable of having an exchange coupling interaction with the anisotropy variable layer and generating a spin orbit torque.

[0044] In the magnetic sensor having the bias magnetic field source described above, the bias magnetic field source may include at least one of a coil that generates an induced magnetic field when energized and a permanent magnet. In this case, the spin Hall layer and the anisotropic variable layer 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 may be arranged side by side in the second direction, in which case the bias magnetic field source may form a stacked structure with the magnetic control body. Alternatively, the spin Hall layer and the anisotropic variable layer 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 may be arranged along the second direction, in which case the bias magnetic field source and the magnetic control body may be arranged side by side in a direction having an in-plane component of the first surface.

[0045] In the above-described magnetic sensors of type A, type B, or type C, the anisotropy variable layer may have at least one of crystalline magnetic anisotropy and shape magnetic anisotropy, in which case the crystalline magnetic anisotropy and / or the shape magnetic anisotropy may serve as the bias magnetic field source.

[0046] In another aspect, the present invention provides a magnetic measurement method using a magnetic sensor comprising: a magnetic sensing element having a sensitivity axis along a first direction; an anisotropic variable layer having a portion made of a ferromagnetic material and capable of taking on a first state and a second state in which the magnetic state differs, including at least one of effective permeability and magnetization direction; a spin Hall layer that changes the magnetic state of the anisotropic variable layer; 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 anisotropic variable layer is in the first state and a second output from the variable magnetic field detection unit when the anisotropic variable layer is in the second state. The magnetic measurement method comprises: a first measurement step of obtaining a first output with the anisotropic variable layer in a first state while the measurement magnetic field is applied; a second measurement step of obtaining a second output with the anisotropic variable layer in a second state while 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.

[0047] Based on the first output obtained in the first measurement step and the second output obtained in the second measurement step, the measured magnetic field is calculated in the magnetic field calculation step, so that a measured magnetic field from which 1 / f noise of the magnetoresistive element is removed can be obtained. For example, by using the difference between the first output and the second output in the magnetic field calculation step, 1 / f noise can be removed from the first output.

[0048] 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 having a high magnetic resolution that can measure a small magnetic field with high accuracy.

[0049] This is a block diagram of a magnetic sensor according to one embodiment of the present invention. This is an explanatory diagram of a magnetic field detection unit provided in a magnetic sensor according to one embodiment of the present invention. This is a diagram illustrating a variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) provided in a magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating a variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) provided in a magnetic sensor according to the first embodiment of the present invention. This is a flowchart illustrating a magnetic measurement method using a magnetic sensor according to the first embodiment of the present invention. This is an explanatory diagram of a preferred example of a variable magnetic field detection unit provided in a magnetic sensor according to the first embodiment of the present invention. This is an explanatory diagram of another preferred example of a variable magnetic field detection unit provided in a magnetic sensor according to the first embodiment of the present invention. This is an explanatory diagram of yet another preferred example of a variable magnetic field detection unit provided in a magnetic sensor according to the first embodiment of the present invention. This is an explanatory diagram of a modified example of a variable magnetic field detection unit provided in a magnetic sensor according to the first embodiment of the present invention. This is a diagram illustrating a variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) provided in a magnetic sensor according to the second embodiment of the present invention. This is a diagram illustrating a preferred example of a variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) provided in a magnetic sensor according to the second embodiment of the present invention. This figure illustrates the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of a magnetic sensor according to an embodiment (Embodiment 1-1) having a variable magnetic field detection unit of type A and a configuration of the first embodiment (the anisotropic variable layer and the magnetosensitive part of the magnetic detection element are magnetically uncoupled). This figure illustrates the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Embodiment 1-1. This figure illustrates the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Embodiment 1-1. This figure illustrates the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Embodiment 1-1. This figure illustrates the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of a magnetic sensor according to an embodiment (Embodiment 1-2) having a variable magnetic field detection unit of type A and a configuration of the second embodiment (the anisotropic variable layer and the magnetosensitive part of the magnetic detection element are magnetically coupled).This figure illustrates the state in which a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 1-2. This figure illustrates the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 1-2. This figure illustrates the state in which a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 1-2. This figure illustrates the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 2-1, which has a variable magnetic field detection unit of type B and a configuration of the first embodiment (the anisotropic variable layer and the magnetosensitive part of the magnetic detection element are magnetically uncoupled). This figure illustrates the state in which a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 2-1. This figure illustrates the state of the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 2-1 before a measurement magnetic field is applied. This figure illustrates the state of the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 2-1 after a measurement magnetic field has been applied. This figure illustrates the state of the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 2-2, in which the variable magnetic field detection unit is of type B and has a configuration of a second embodiment (the anisotropic variable layer and the magnetosensitive part of the magnetic detection element are magnetically coupled) before a measurement magnetic field is applied. This figure illustrates the state of the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 2-2 after a measurement magnetic field has been applied. This figure illustrates the state of the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 2-2 before a measurement magnetic field is applied. This figure illustrates the state in which a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 2-2. This figure illustrates the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 3-1, which has a variable magnetic field detection unit of type C and a configuration of the first embodiment (the anisotropic variable layer and the magnetosensitive part of the magnetic detection element are magnetically uncoupled).This figure illustrates the state in which a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 3-1. This figure illustrates the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 3-1. This figure illustrates the state in which a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 3-1. This figure illustrates the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 3-2, which has a variable magnetic field detection unit of type C and a configuration of the second embodiment (the anisotropic variable layer and the magnetosensitive part of the magnetic detection element are magnetically coupled). This figure illustrates the state in which a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 3-2. This figure illustrates the state of the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 3-2 before a measurement magnetic field is applied. This figure illustrates the state of the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 3-2 after a measurement magnetic field has been applied. This figure illustrates the state of the magnetic sensor according to Example 2-1m, which is another modification of Example 2-1, when the anisotropic variable layer is in the second state and before a measurement magnetic field is applied. This figure illustrates the state of the magnetic sensor according to Example 2-1m when the anisotropic variable layer is in the second state and a measurement magnetic field has been applied. This figure illustrates the state of the magnetic sensor according to Example 2-2m, which is another modification of Example 2-2, when the anisotropic variable layer is in the second state and before a measurement magnetic field is applied. This figure illustrates the state of the magnetic sensor according to Example 2-2m when the anisotropic variable layer is in the second state and a measurement magnetic field has been applied. This figure illustrates one modification of the variable magnetic field detection unit according to Example 1-1. This figure illustrates another modification of the variable magnetic field detection unit according to Example 1-1. This figure illustrates one modified example of the variable magnetic field detection unit according to Example 1-2. This figure illustrates another modified example of the variable magnetic field detection unit according to Example 1-2. This figure illustrates one modified example of the variable magnetic field detection unit according to Example 2-1 and Example 3-1.This is a diagram illustrating another modified example of the variable magnetic field detection unit according to Example 2-1 and Example 3-1. This is a diagram illustrating another modified example of the variable magnetic field detection unit according to Example 2-2 and Example 3-2. This is a diagram illustrating another modified example of the variable magnetic field detection unit according to Example 2-2 and Example 3-2. This is an explanatory diagram of a modified example of the variable magnetic field detection unit according to Example 2-1.

[0050] Embodiments of the present invention will be described below with reference to the accompanying drawings. In each drawing, the same component is given the same number, and its description is omitted. Reference coordinates are shown in each drawing as appropriate to indicate the positional relationship of each component.

[0051] Figure 1 is a block diagram of a magnetic sensor according to one embodiment of the present invention. Figure 2 is an explanatory diagram of the magnetic field detection unit included 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 and an amplifier 5, an analog-to-digital conversion circuit (A / D conversion circuit 6), and a control unit 7. The control unit 7 controls each part that constitutes the magnetic sensor 1 and is configured as a CPU (central processing unit) and a program, etc.

[0052] The magnetic field detection unit 2 detects the external magnetic field to be measured. As shown in Figure 2, the magnetic field detection unit 2 is composed of a full-bridge circuit 15 consisting of magnetic detection elements 10a, 10b, 10c, and 10d that measure the magnetic field 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 detection elements 10a, 10b, 10c, and 10d, respectively. The control power supply 3 applies a predetermined current or a predetermined voltage to each part, including the magnetic field detection unit 2, based on a control signal from the control unit 7.

[0053] 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 composed of, for example, a CDS (Correlated Double Sampling) circuit. The magnetic field calculation unit 4 calculates the measured magnetic field H based on the first output from the variable magnetic field detection units 100a, 100b, 100c, and 100d when the magnetic state of the anisotropic variable layer 40, described later, is in the first state, and the second output from the variable magnetic field detection units 100a, 100b, 100c, and 100d when the magnetic state of the anisotropic variable layer 40 is in the second state. For example, 1 / f noise can be removed from the first output by determining the difference between the signal based on the first output and the signal based on the second output.

[0054] In the magnetic sensor 1, the magnetic field calculation unit 4 calculates the measurement magnetic field H, then the signal corresponding to the calculated measurement magnetic field H is amplified by the amplifier 5, and then converted into digital data by the A / D conversion circuit 6.

[0055] The four magnetic sensing elements 10a, 10b, 10c, and 10d 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 sensing elements 10a, 10b, 10c, and 10d are provided on the same substrate (not shown), and Figure 2 is a view of the magnetic field detection unit 2 of the magnetic sensor 1 as seen from the laminated surface (front surface) of the substrate in the direction normal to the substrate. That is, in Figure 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 is along the lamination direction of the magnetic sensing elements 10a, 10b, 10c, and 10d.

[0056] The magnetic field detection unit 2 has a full bridge circuit 15 in which a first half-bridge circuit, in which magnetic detection elements 10a and 10b, both extending in the Y direction, are connected in series between the power supply terminal Vdd, which is the power supply point, and the ground terminal GND, and a second half-bridge circuit, in which magnetic detection elements 10c and 10d, both extending in the Y direction, are connected in series, are connected in parallel.

[0057] The first half-bridge circuit has an output terminal V1 between magnetic sensing elements 10a and 10b. The second half-bridge circuit has an output terminal V2 between magnetic sensing elements 10c and 10d. The potential difference between 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) allows for the quantitative measurement of the magnitude of an externally applied magnetic field H as the measurement magnetic field. In this embodiment, a first signal including the midpoint potential Va from output terminal V1 and a second signal including the midpoint potential Vb from output terminal V2 are output from the magnetic field detection unit 2, and the processing performed by the magnetic field calculation unit 4 includes calculating the midpoint potential difference using these first and second signals as input.

[0058] In the pair of magnetic sensing elements 10a and 10b forming the first half-bridge circuit, the magnetization 11m of the fixed magnetic layer 11 (see Figure 3A) is in the X direction X2 (hereinafter abbreviated as "X2 direction"; the same applies to other directions) and X1 direction, as shown by the white arrows in Figure 2. Similarly, in the pair of magnetic sensing elements 10c and 10d forming the second half-bridge circuit, the magnetization 11m of the fixed magnetic layer 11 is in the X1 direction and X2 direction, as shown by the white arrows in Figure 2.

[0059] In the first half-bridge circuit and the second half-bridge circuit, the magnetization 11m of the fixed magnetic layer 11 between the magnetic detection element 10b and the magnetic detection element 10d on the power terminal Vdd side is in opposite directions (antiparallel). Also, the magnetization 11m of the fixed magnetic layer 11 between the magnetic detection element 10a and the magnetic detection element 10c on the ground terminal GND side is in opposite directions (antiparallel). Therefore, the sensitivity axis direction of the magnetic detection 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."

[0060] Furthermore, the four magnetic sensing elements 10a, 10b, 10c, and 10d have the same direction of magnetization 13m of the free magnetic layer 13 (see Figure 3A) when no measurement magnetic field H is applied, and are aligned in the Y2 direction as shown by the black arrows in Figure 2. The method for aligning the direction of magnetization 13m of the free magnetic layer 13 when no measurement magnetic field H is applied is not limited. A bias magnetic field may be applied from the outside, or exchange coupling with an antiferromagnetic layer that interacts with the free magnetic layer 13 may be used.

[0061] With the above configuration, as the magnitude of the measured magnetic field H in the X direction changes, the outputs from the output terminal V1 of the first half-bridge circuit and the output terminal V2 of the second half-bridge circuit change in opposite directions. Therefore, a large output is obtained as the potential difference between the two output terminals V1 and V2. Thus, the magnetic sensor 1 can detect the measured magnetic field H with high precision. In addition, the first half-bridge circuit or the second half-bridge circuit can be used instead of the full-bridge circuit 15, or the magnetic detection element 10a can be used alone.

[0062] As shown in Figure 2, the magnetic sensor 1 according to this embodiment includes variable magnetic field detection units 100a, 100b, 100c, and 100d that measure the magnetic field H by changing the surrounding magnetic environment, corresponding to the magnetic detection elements 10a, 10b, 10c, and 10d, respectively. The variable magnetic field detection unit 100a will be described below as a specific example.

[0063] (First Embodiment) Figure 3A is a diagram illustrating a variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of a magnetic sensor according to the first embodiment of the present invention. The variable magnetic field detection unit 100a comprises a first magnetic material 31 and a second magnetic material 32 that are magnetized by a measuring magnetic field H along a first direction, a magnetic detection element 10a located between the first magnetic material 31 and the second magnetic material 32 in the first direction, an anisotropic variable layer 40 whose magnetic state can be changed, and a spin Hall layer 20 that changes the magnetic state of the anisotropic variable layer 40. In this specification, the concept of "magnetization" used for magnetic members such as the anisotropic variable layer 40 also includes the generation of a magnetic field inside the member based on a physical phenomenon different from the magnetization of a ferromagnetic material (for example, a virtual magnetic field that arises based on the topological properties of an antiferromagnetic material).

[0064] The first magnetic material 31 and the second magnetic material 32 may be made of any material as long as they can be magnetized in the first direction by a measuring 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 material 31 and the second magnetic material 32 function as magnetizers (yokes) that collect and magnetize the measuring magnetic field H in the first direction. As shown in Figure 3A, when the measuring magnetic field H is in one direction of the first direction, specifically in the X1 direction, the measuring magnetic field H is collected by the first magnetic material 31 and magnetizes the first magnetic material 31. As a result, a magnetic flux with a density higher than the measuring magnetic field H (hereinafter also referred to as "measuring magnetic flux Φ") is generated in the first magnetic material 31, and this measuring magnetic flux Φ is emitted in the first direction from the first end 311, which is the end on the first direction side (X1 side) of the first magnetic material 31. Since the permeability μ0 of the insulator 50, which is made up of the first material located around the first magnetic material 31 and the second magnetic material 32, is sufficiently lower than the permeability of the first magnetic material 31 and the second magnetic material 32, the measured magnetic flux Φ emitted from the first end 311 in the first direction diffuses in the second and third directions within the first material, but converges towards the X2 side end of the second magnetic material 32.

[0065] The magnetic sensing element 10a is located in a first orientation relative to the first end portion 311, which is the first orientation side (X1 side) end of the first magnetic material 31, and has a sensitivity axis along the first direction. Specific examples of the magnetic sensing element 10a include magnetoresistive elements such as giant magnetoresistance (GMR) elements and tunnel magnetoresistance (TMR) elements, and Hall elements. Figure 3A shows a giant magnetoresistance (GMR) element as a specific example of the magnetic sensing element 10a. The magnetic sensing element 10a is located between the first magnetic material 31 and the second magnetic material 32. In other words, the second magnetic material 32 is provided distal to the magnetic sensing element 10a in the first direction (X direction) relative to the first end portion 311 of the first magnetic material 31. The first magnetic material 31 and the second magnetic material 32 collect the measurement magnetic field H in the first direction (X direction) and increase the magnetic flux density between the first magnetic material 31 and the second magnetic material 32. As a result, the magnetic detection element 10a has a higher magnetic resolution than when the first magnetic material 31 and the second magnetic material 32 are not provided.

[0066] The magnetic sensing element 10a, which consists of a giant magnetoresistance effect element, has a fixed magnetic layer 11, a free magnetic layer 13, and an intermediate layer 12 formed between the fixed magnetic layer 11 and the free magnetic layer 13. The fixed magnetic layer 11 is made of a magnetic material such as 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 CoFe alloy or NiFe alloy (nickel-iron alloy), and is formed as a single-layer structure, a multilayer structure, a multilayer ferristructure, etc. When the magnetic sensing element 10a consists of a tunnel magnetoresistance effect element, the intermediate layer 12 is an insulating barrier layer made of MgO, Al2O3, titanium oxide, etc.

[0067] The resistance value of the magnetic sensing element 10a changes depending on the relative magnetization direction between the fixed magnetic layer 11, in which the direction of magnetization 11m is fixed, and the free magnetic layer 13, which is a magnetosensitive part in which the direction and magnitude of magnetization 13m change due to the external magnetic field. The variable magnetic field detection unit 100a of the magnetic sensor 1 can measure the direction and strength of the external magnetic field based on the change in the resistance value of the magnetic sensing element 10a. In this embodiment, the free magnetic layer 13 is located on the Z2 side of the magnetic sensing element 10a, and the detection center 10P of the magnetic sensing element 10a is located at the center of the free magnetic layer 13.

[0068] The anisotropic variable layer 40 has a portion made of ferromagnetic material and is a member that can take on a first state and a second state in which the magnetic state differs, including at least one of the effective permeability and the direction of the magnetization 40m described later, and the magnetic state is controlled by the spin Hall layer 20. The anisotropic variable layer 40 is located on the first direction side (X1 side) of the first end 311 of the first magnetic material 31, and in the example shown in Figure 3A, it is located between the first magnetic material 31 and the second magnetic material 32 in the first direction.

[0069] In this specification, the "effective permeability" of the anisotropic variable layer 40 is evaluated based on its shielding function, which reduces the magnetic flux density reaching the free magnetic layer 13 by concentrating the magnetic flux in the anisotropic variable layer 40 when subjected to an external magnetic field in a predetermined direction. For example, if the relative permeability around the anisotropic variable layer 40 is 1, and the anisotropic variable layer 40 has the function of further concentrating the external magnetic field when subjected to an external magnetic field having a component along the first direction, then it is determined that the effective relative permeability of the anisotropic variable layer 40 in the first direction exceeds 1. Therefore, as described above, if the effective relative permeability of the anisotropic variable layer 40 in the first direction exceeds 1, the magnetic flux density around the anisotropic variable layer 40 (including the free magnetic layer 13) will decrease due to the shielding function of the anisotropic variable layer 40.

[0070] In one specific example, the anisotropic variable layer 40 has an effective permeability μ2 in the first direction (X direction) in the second state that is higher than the effective permeability μ1 in the first direction (X direction) in the first state. Furthermore, the effective permeability μ2 in the first direction (X direction) in the second state is higher than the permeability μ0 in the first direction (X direction) of the first material located between the first magnetic material 31 and the magnetic sensing element 10a. In this embodiment, the first material is an insulator 50.

[0071] In the first embodiment, the anisotropic variable layer 40 and the spin Hall layer 20 are stacked in the second direction (Z direction) to form a magnetic control body 60, and a non-magnetic member 41 is provided between the magnetic control body 60 and the magnetic sensing element 10a, and the anisotropic variable layer 40 of the magnetic control body 60 and the free magnetic layer 13 of the magnetic sensing element 10a are magnetically uncoupled by the non-magnetic member 41.

[0072] (First State) As shown in Figure 3A, the measurement magnetic field H is focused on the first magnetic material 31 which functions as a yoke, and the first magnetic material 31 is magnetized by this magnetic field, and the measurement magnetic flux Φ is emitted from the first end 311 of the first magnetic material 31. In the first state, the effective permeability μ1 of the anisotropic variable layer 40 in the X direction is not much 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 material 31, diffusing so that it has a component in the X1 direction while also having components in the second direction (Z direction) and the third direction (Y direction). Subsequently, it converges between the first magnetic material 31 and the second magnetic material 32 so that the components in the second and third directions become smaller, and reaches the second magnetic material 32 which is located closer to X1 than the first magnetic material 31. In this way, a portion of the diffusing and converging magnetic flux Φ reaches the free magnetic layer 13 of the magnetic detection element 10a and is measured by the magnetic detection element 10a. The measurement result of the magnetic detection element 10a in this first state becomes the first output of the variable magnetic field detection unit 100a.

[0073] (Second State) Figure 3B is a diagram illustrating the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is the second state) of the magnetic sensor according to the first embodiment of the present invention. In the second state, the effective permeability μ2 in the X direction of the anisotropic variable layer 40 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 anisotropic variable layer 40. Due to this concentration of the measurement magnetic flux Φ in the anisotropic variable layer 40, the density of the measurement magnetic flux Φ reaching the free magnetic layer 13 decreases compared to the first state, and the measurement sensitivity of the measurement magnetic flux Φ decreases in the magnetic detection element 10a located near the anisotropic variable layer 40. Consequently, the second output from the variable magnetic field detection unit 100a in the second state has the same noise signal intensity as the first output in the first state, but the signal intensity based on the measurement magnetic flux Φ decreases.

[0074] Figure 4 is a flowchart illustrating a magnetic measurement method using a magnetic sensor according to a first embodiment of the present invention. As shown in Figure 4, first, as a first measurement step, a control signal output from the control unit 7 causes the control power supply 3 to output a signal to set the magnetic state of the anisotropic variable layer 40 of each of the variable magnetic field detection units 100a to 100d of the magnetic field detection unit 2 to a first state. With the anisotropic variable layer 40 in the first state, measurements are performed by the magnetic detection elements 10a, 10b, 10c, and 10d, and a first output is obtained from each of the variable magnetic field detection units 100a, 100b, 100c, and 100d. Based on these signals, the magnetic field detection unit 2 outputs a first signal (a signal including the midpoint potential Va from output terminal V1) and a second signal (a signal including the 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 stored in the magnetic field calculation unit 4 or a memory (not shown) either as the signals themselves or as a signal representing the midpoint potential difference, which is the difference between the two signals.

[0075] Next, in the second measurement step, a control signal output from the control unit 7 causes the control power supply 3 to output a signal to set the magnetic state of the anisotropic variable layer 40 of each of the variable magnetic field detection units 100a, 100b, 100c, and 100d of the magnetic field detection unit 2 to a second state. With the anisotropic variable layer 40 in the second state, measurements are performed by the magnetic detection elements 10a, 10b, 10c, and 10d, and a second output is obtained from each of the variable magnetic field detection units 100a, 100b, 100c, and 100d. Based on these signals, the magnetic field detection unit 2 outputs a first signal and a second signal (step S102). The measurement time for both steps S101 and S102 is sufficiently shorter than one second (for example, 0.3 seconds), and the time required for steps S101 and S102 is also sufficiently shorter than one second (for example, 0.7 seconds). Therefore, steps S101 and S102 are performed in an environment where the 1 / f noise is substantially equal, and the 1 / f noise included in the first output and the 1 / f noise included in the second output are substantially equal. 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 a memory (not shown) either as the signals themselves or as a signal of the midpoint potential difference, which is the difference between the two signals.

[0076] Next, the magnetic field calculation unit 4 performs a magnetic field calculation step (step S103) to determine the difference between the signal based on the first output (a signal including the midpoint potential difference of the first state) and the signal based on the second output (a signal including the midpoint potential difference of the second state), which are 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 determined, the magnetic field calculation unit 4 performs a process to determine the difference between the first signal and the second signal of the first state to obtain a signal including the midpoint potential difference of the first state, and also performs a process to determine the difference between the first signal and the second signal of the second state to obtain a signal including the midpoint potential difference of the second state, and further performs a process to determine the difference between these two signals including the midpoint potential difference, as a magnetic field calculation step. By performing the above process, the magnetic field calculation unit 4 obtains a measurement signal from which 1 / f noise has been appropriately removed. This 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 according to this embodiment has 1 / f noise appropriately removed, and thus has a higher resolution (magnetic resolution) of the signal based on the measured magnetic flux Φ than the signal based on the first output (a signal including the midpoint potential difference of the first state) or the signal based on the second output (a signal including the midpoint potential difference of the second state).

[0077] In this embodiment, since the magnetic field detection unit 2 has a full bridge circuit 15, the signals that the magnetic field calculation unit 4 processes for difference are the signal of the midpoint potential difference of the first state based on the first output and the signal of the midpoint potential difference of the second state based on the second output. However, the signals that the magnetic field calculation unit 4 processes are set appropriately according to the output signals 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 calculate the difference between the first signal and the second signal from the variable magnetic field detection unit 100a.

[0078] (Arrangement Relationship) The arrangement relationship between the magnetic sensing element 10a and the anisotropic variable layer 40 is preferably set such 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 is large.

[0079] From this perspective, the magnetic sensing element 10a and the anisotropic variable layer 40 may be aligned in a second direction (Z direction) perpendicular to the first direction (X direction). In this arrangement, changes in the magnetic state of the anisotropic variable layer 40 tend to manifest as changes in the strength of the measured magnetic flux Φ reaching the detection center 10P of the magnetic sensing element 10a.

[0080] It is preferable that the anisotropic variable layer 40 has a portion that is closer to the first magnetic material 31 in the first direction (X direction) than the detection center 10P of the magnetic detection element 10a. When this arrangement is in place, in the second state, the measured magnetic flux Φ emitted from the first end 311 is more likely to reach the anisotropic variable layer 40 which is relatively closer in the first direction, thus efficiently concentrating the magnetic flux onto the anisotropic variable layer 40 in the second state. From this viewpoint, it is preferable that the length of the anisotropic variable layer 40 in the first direction is longer than the length of the magnetic detection element 10a in the first direction (X direction).

[0081] It is preferable that the center of the anisotropic variable layer 40 in the first direction (X direction) and the detection center 10P of the magnetic detection element 10a are at the same position in the first direction (X direction). When this arrangement is in place, the magnetic flux in the first direction (X direction) that the anisotropic variable layer 40 in the first state can exert on the magnetic detection element 10a tends to be equal to the magnetic flux in the first direction that the anisotropic variable layer 40 in the second state can exert on the magnetic detection element 10a. As a result, the correlation between the noise signal included in the first output and the noise signal included in the second output increases, and it is expected that the noise removal efficiency in the measurement signal obtained by the magnetic field calculation unit 4 will increase. Furthermore, from the viewpoint of stably increasing the noise removal efficiency in the measurement signal and from the viewpoint of improving the operational stability of the anisotropic variable layer 40, it is preferable that the center of the anisotropic variable layer 40 in the first direction (X direction) and the center of the spin Hall layer 20 in the first direction (X direction) are at the same position.

[0082] Preferably, the length of the anisotropic variable layer 40 in the first direction (X direction) is longer than the length of the magnetic sensing element 10a in the first direction (X direction). In this arrangement, a portion of the X2 side of the anisotropic variable layer 40 is located between the first end 311 and the magnetic sensing element 10a in the first direction (X direction), so the magnetic flux density reaching the magnetic sensing element 10a is easily affected by the magnetic state of the anisotropic variable layer 40.

[0083] From the viewpoint of more stably realizing that the magnetic flux density reaching the magnetic sensing element 10a is susceptible to the influence of the magnetic state of the anisotropic variable layer 40, it is preferable that the anisotropic variable layer 40 is arranged such that the first magnetic material 31 and the second magnetic material 32 are magnetically coupled in the second state. Figure 5 is an explanatory diagram of a preferred example of a variable magnetic field detection unit included in a magnetic sensor according to the first embodiment of the present invention. In the example shown in Figure 5, when viewed from the second direction (Z direction), the anisotropic variable layer 40 is arranged such that it is magnetically coupled with the first magnetic material 31 and the second magnetic material 32 in the second state. Specifically, the anisotropic variable layer 40 has a portion that overlaps with the first magnetic material 31 and a portion that overlaps with the second magnetic material 32. Therefore, as shown in Figure 5, the measured magnetic flux Φ generated by the magnetization of the first magnetic material 31 flows almost directly from the magnetic coupling between the anisotropic variable layer 40 and the first magnetic material 31 into the anisotropic variable layer 40 in the second state, and flows almost directly from the magnetic coupling between the anisotropic variable layer 40 and the first magnetic material 31 into the second magnetic material 32. As a result, the measured magnetic flux Φ does not effectively have a component that reaches the magnetic detection element 10a, and only noise signals are more likely to be measured by the magnetic detection element 10a.

[0084] Figure 6 is an explanatory diagram 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. In the configuration shown in Figure 6, the arrangement of the components of the magnetic detection element 10a is reversed in the Z direction compared to the configuration shown in Figure 5. That is, in Figure 5, the free magnetic layer 13 of the magnetic detection element 10a is located on the side (Z2 side) closer to the magnetic control body 60, but in Figure 6, the fixed magnetic layer 11 of the magnetic detection element 10a is located on the side (Z2 side) closer to the magnetic control body 60. For this reason, in the configuration shown in Figure 6, the detection center 10P of the magnetic detection 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 Figure 5. Therefore, in the first state, the intensity of the component in the direction of X1 in the measured magnetic flux Φ reaching the detection center 10P of the magnetic detection element 10a is expected to be relatively higher.

[0085] Figure 7 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 Figure 7, the arrangement relationship between the magnetic detection element 10a and the magnetic control body 60 in the second direction (Z direction) is reversed compared to the configuration shown in Figure 5. That is, in Figure 5, the magnetic detection element 10a is located on the Z1 side of the magnetic control body 60, but in Figure 7, the magnetic detection element 10a is located on the Z2 side of the magnetic control body 60. For this reason, in the configuration shown in Figure 7, the detection center 10P of the magnetic detection element 10a is further 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 Figure 5. Therefore, in the second state, it is expected that the intensity of the measured magnetic flux Φ reaching the detection center 10P of the magnetic detection element 10a will be particularly low. Furthermore, as viewed from the first end 311, the magnetic sensing element 10a is located in the shadow of the magnetic control body 60. Therefore, even if a portion of the measured magnetic flux Φ is emitted from the first end 311 into the insulator 50, the magnetic control body 60 acts as a magnetic shield, making it difficult for that magnetic flux to reach the magnetic sensing element 10a. Consequently, in the second state, only noise signals are more likely to be measured by the magnetic sensing element 10a.

[0086] Figure 8 is an explanatory diagram of a modified example of the variable magnetic field detection unit of the magnetic sensor according to the first embodiment of the present invention. In the modified structure shown in Figure 8, the second magnetic material 32 is omitted compared to the structure shown in Figure 3A. In this case, the intensity of the measured magnetic flux Φ decreases due to the absence of the second magnetic material 32, which may reduce the sensitivity of the magnetic detection element 10a, but it is possible to reduce the footprint (projected area in the XY plane) of the variable magnetic field detection unit 100a. In the structure shown in Figure 8, the second magnetic material 32 is omitted, but the first magnetic material 31 may also be omitted.

[0087] Furthermore, when the measured magnetic field H is in the first direction (X direction), it is preferable that the length of the first magnetic material 31 in the first direction (X direction) is longer than the length in the second direction (Z direction). If the length relationship is reversed (length in the first direction < length in the second direction), the possibility of detecting a magnetic field in the second direction (Z direction) increases.

[0088] (Second Embodiment) Figure 9 is a diagram illustrating the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is the second state) of the magnetic sensor according to the second embodiment of the present invention. In the second embodiment, in contrast to the first embodiment, the non-magnetic member 41 is not provided, and the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled. Therefore, in the second embodiment, in the second state, the anisotropic variable layer 40 functions substantially as the free magnetic layer 13. Therefore, in the second state, the detection sensitivity of the magnetic detection element 10a is directly affected by the magnetic state of the anisotropic variable layer 40.

[0089] For example, in the second state, the effective permeability μ2 of the anisotropic variable layer 40 in the first direction is higher than the permeability μ0 of the surrounding insulator 50. As shown in Figure 9, the measured magnetic flux Φ preferentially concentrates in the anisotropic variable layer 40. In this case, a portion of the measured magnetic flux Φ that is magnetized in the anisotropic variable layer 40 and propagates in the direction of X1 also passes through the free magnetic layer 13 which is magnetically coupled to the anisotropic variable layer 40, and its direction has a component in the direction of X1. Therefore, in the second embodiment, the intensity of the measured magnetic flux Φ reaching the free magnetic layer 13 may be higher in the second state than in the first state.

[0090] In contrast, in the first state, the effective permeability μ1 of the anisotropic variable layer 40 in the first direction is equivalent to the permeability μ0 of the surrounding insulator 50. Therefore, the degree of the shielding function of the anisotropic variable layer 40 (the function of reducing the intensity of the measured magnetic flux Φ reaching the free magnetic layer 13) is lower than in the second state. For this reason, even if the measured magnetic flux Φ reaches the free magnetic layer 13 which is magnetically coupled to the anisotropic variable layer 40, the magnetic flux density will be lower than in the second state.

[0091] Thus, in the second embodiment, the measured 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.

[0092] In the second embodiment, since the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled, the anisotropic variable layer 40 and the free magnetic layer 13 may be made of a common material, and one component (variable free magnetic layer) may perform the functions of both the anisotropic variable layer 40 and the free magnetic layer 13. In this case, an intermediate layer 12 and a fixed magnetic layer 11 may be laminated on a part of the surface of the variable free magnetic layer facing Z1 to form a magnetic sensing element 10a having the structure of a magnetoresistive element. The variable free magnetic layer can be made of the same material as the material that constitutes the anisotropic variable layer 40. Therefore, the concept of "magnetization" in relation to the variable free magnetic layer is broader than the magnetization of a ferromagnetic material, and includes, for example, a virtual magnetic field based on the topological properties of an antiferromagnetic material.

[0093] Figure 10 illustrates a preferred example of a variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is the second state) of a magnetic sensor according to a second embodiment of the present invention. In the example shown in Figure 10, similar to the example shown in Figure 5, in the second state, the anisotropic variable layer 40 is magnetically coupled with the first magnetic material 31 and the second magnetic material 32. Therefore, in the second state, the free magnetic layer 13 is magnetically coupled with the first magnetic material 31 and the second magnetic material 32. Consequently, in the second state, the measured magnetic flux Φ reaches the free magnetic layer 13 particularly efficiently.

[0094] In the variable magnetic field detection unit 100a of the magnetic sensor 1 according to an embodiment of the present invention, the density of the measured magnetic flux Φ reaching the free magnetic layer 13 differs between a first state, where the effective permeability in the first direction of the anisotropic variable layer 40 is relatively low, and a second state, where it is relatively high. Whether the state in which the measured magnetic flux Φ reaching the free magnetic layer 13 is relatively high is the first state or the second state is determined by the specific configuration.

[0095] The following describes the detailed operation of the variable magnetic field detection unit 100a, using as specific examples: a configuration in which a spin orbit torque is applied to the anisotropic variable layer 40 by energizing the spin Hall layer 20, thereby magnetizing the anisotropic variable layer 40 in a predetermined direction; a configuration in which the spin Hall layer 20 is energized along a third direction (Y direction) to magnetize the spin Hall layer 20 in the third direction (Y direction) (Type A); a configuration in which the spin Hall layer 20 is energized along a first direction (X direction) to magnetize the spin Hall layer 20 in the third direction (Y direction) (Type B); and a configuration in which the spin Hall layer 20 is energized along a third direction (Y direction) to magnetize the spin Hall layer 20 in the second direction (Z direction) (Type C).

[0096] (Example 1-1) Figure 11A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of a magnetic sensor according to an example (Example 1-1) in which the variable magnetic field detection unit is of type A and has a configuration of the first embodiment (the anisotropic variable layer and the magnetosensitive part of the magnetic detection element are magnetically uncoupled). Figure 11B is a diagram illustrating the state after a measurement magnetic field has been applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 1-1. In the variable magnetic field detection unit 100a shown in Figures 11A and 11B, the first magnetic material 31, the second magnetic material 32, and the insulator 50 are omitted from the display (the same applies hereinafter). Also, in Figure 11B, the wiring etc. shown in Figure 11A are omitted from the display.

[0097] In Example 1-1, the spin Hall layer 20 has a spin torque generation unit that applies spin orbit torque to the anisotropic variable layer 40 by applying current to the spin Hall layer 20 in the XY plane, thereby exhibiting the spin Hall effect and the Rashba-Edelstein effect. In this example, as shown in Figure 11A, the control wiring 61 is provided so that a current (control current 20c, described later) from a control current source I, which is part of the control power supply 3, is applied to the spin Hall layer 20 in a third direction (Y direction). In addition, for the purpose of measuring the electrical characteristics of the magnetic sensing element 10a, the 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 in a second direction (Z direction) between the free magnetic layer 13 and the fixed magnetic layer 11 of the magnetic sensing element 10a. In this example, the magnetic detection element 10a and the magnetic control body 60 are stacked in the second direction (Z direction), and the magnetic control body 60 is made of a conductive material. Therefore, the measurement wiring 62 is provided so that the voltage from the measurement voltage source V is applied to the free magnetic layer 13 via the magnetic control body 60.

[0098] In this example, the spin Hall layer 20 is a film-like body, and its entirety may consist of a spin torque generating section. In the configuration shown in Figure 11A, the spin Hall layer 20 consists of a spin torque generating section. As materials constituting the spin torque generating section, heavy metals (5d transition metals) with high specific gravity among paramagnetic transition metals such as Hf, Ta, W, Pt, and Ir; topological insulators such as BiSb, BiSe, Bi2Se3, and Bi2Te3; Mn3X (X = Sn, Ge, Ga, Rh, Pt, Ir); Mn 1-x Tr x Examples include antiferromagnetic materials such as the gamma phase (Tr = Ni, Fe, Cu, Ru, Pd, Ir, Rh, Pd, Pt); and half-Heusler alloy topological semimetals made of LuPtSb, LuPdBi, LuPtBi, ScPtBi, YAuPb, LaPtBi, CePtBi, ThPtPb, and LaAuPb, or mixed crystals thereof. The spin torque generating region may consist of a single-phase film or a multilayer film. In the case of a multilayer film, boundary regions may be formed between adjacent films.

[0099] The anisotropic variable layer 40 is composed of a material that allows the magnetization 40m of the anisotropic variable layer 40 to rotate in response to the spin orbit torque from the spin Hall layer 20. Examples of such materials include ferromagnetic materials such as soft magnetic materials like CoFe alloy and NiFe alloy (nickel-iron alloy). The anisotropic variable layer 40 may be composed of a single-phase film or a multilayer film. In the case of a multilayer film, boundary regions may be formed between adjacent films.

[0100] 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 integrated with the insulator 50.

[0101] In the variable magnetic field detection unit 100a according to this example, the spin Hall layer 20 has an antiferromagnetic portion made of an antiferromagnetic material, and as a specific example, the entire spin Hall layer 20 is made of an antiferromagnetic portion. Therefore, when the spin Hall layer 20 is not energized, as shown in Figure 11A, the magnetization 40m of the anisotropic variable layer 40 is oriented in the Z1 direction due to exchange coupling 20af with the spin Hall layer 20 (antiferromagnetic portion). Rotation of the magnetization 40m is unlikely to occur in the Z direction because the thickness is small. Therefore, the magnetization 40m of the anisotropic variable layer 40 is substantially 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, becomes low. Therefore, in the X direction, the effective permeability μ1 of the anisotropic variable layer 40 is almost the same as the permeability μ0 of the surrounding insulator 50, and the anisotropic variable layer 40 is in the first state.

[0102] In this first state, when the measurement magnetic field H is applied, the measurement magnetic flux Φ does not concentrate in the anisotropic variable layer 40. Therefore, as shown in Figure 11B, a considerable amount of the measurement magnetic flux Φ reaches the free magnetic layer 13, and the magnetic detection element 10a measures this reached magnetic flux.

[0103] Figure 12A is a diagram illustrating the state of the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer 40 is in the second state) of the magnetic sensor according to Embodiment 1-1 before a measurement magnetic field is applied. Figure 12B is a diagram illustrating the state of the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer 40 is in the second state) of the magnetic sensor according to Embodiment 1-1 after a measurement magnetic field has been applied. In Figure 12B, the wiring and other elements shown in Figure 12A are omitted from the display.

[0104] In the second state, a current 20c is supplied from the control current source I through the control wiring 61 to the spin Hall layer 20 in the Y direction, specifically in the Y1 direction, thereby energizing the spin Hall layer. As a result, due to the spin Hall effect, spins that are unevenly distributed in the X direction accumulate on the Z1 side of the spin Hall layer 20 and are injected into the anisotropic variable layer 40. The angular momentum of the accumulated spins is directly transferred, causing a torque to act on the magnetization 40m of the anisotropic variable layer 40, that is, a spin orbit torque is generated, and the magnetization 40m becomes Y2 oriented.

[0105] At this time, the magnetization 40m of the anisotropic variable layer 40 is oriented in the in-plane direction of the XY plane (first plane) perpendicular to the thickness direction of the anisotropic variable layer 40, so the magnetization 40m can rotate in the XY plane by the measured magnetic flux Φ. That is, in the second state, the effective permeability μ2 in the X direction of the anisotropic variable layer 40 is higher than the effective permeability μ1 in the X direction of the first state (μ2 > μ1).

[0106] When the measurement magnetic field H is applied in this state, as shown in Figure 12B, the magnetization 40m of the anisotropic variable layer 40 rotates to align with the measurement magnetic flux Φ and faces X1, thereby concentrating the measurement magnetic flux Φ in the anisotropic variable layer 40. In this way, the measurement magnetic flux Φ, which reached the free magnetic layer 13 when the spin Hall layer 20 was not energized, is concentrated in the anisotropic variable layer 40 by applying a current 20c to the spin Hall layer 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.

[0107] Thus, in Example 1-1, the measured magnetic flux Φ reaches the magnetic detection element 10a more easily in the first state than in the second state. Therefore, by subtracting the second output from the first output in the magnetic field calculation unit 4, a measurement signal with 1 / f noise appropriately removed can be obtained.

[0108] (Example 1-2) Figure 13A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of a magnetic sensor according to Example 1-2, which has a variable magnetic field detection unit of type A and a configuration of the second embodiment (the anisotropic variable layer 40 and the magnetosensitive part of the magnetic detection element are magnetically coupled). Figure 13B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 1-2. Figure 14A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 1-2. Figure 14B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 1-2. In Figures 13B and 14B, the wiring and other elements shown in Figures 13A and 14A are omitted from the display.

[0109] The variable magnetic field detection unit 100a according to Example 1-2 differs from the variable magnetic field detection unit 100a according to Example 1-1 in that it does not have a non-magnetic member 41, but the other configurations are the same. For this reason, in the variable magnetic field detection unit 100a according to Example 1-2, the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled. Therefore, as shown in Figure 13A, in the first state, which is an unenergized state in which no current is applied to the spin Hall layer 20, the magnetization 40m of the anisotropic variable layer 40 and the magnetization 13m of the free magnetic layer 13 magnetically coupled to the anisotropic variable layer 40 are oriented in the Z1 direction due to the exchange coupling 20af between the portion of the spin Hall layer 20 made of antiferromagnet and the anisotropic variable layer 40.

[0110] Because the free magnetic layer 13 has a small thickness in the Z direction, its magnetization 13m does not rotate easily. Therefore, the magnetization 40m of the anisotropic variable layer 40 and the magnetization 13m of the free magnetic layer 13 are effectively fixed in the Z1 direction. In other words, the effective permeability in the X direction of the anisotropic variable layer 40 and the free magnetic layer 13 is almost the same as the permeability μ0 of the surrounding insulator 50.

[0111] Even when subjected to a magnetic flux Φ in this state, as shown in Figure 13B, the magnetization 13m of the free magnetic layer 13 does not easily rotate along the X direction, which is the sensitivity axis direction, so the magnetic flux Φ is difficult to measure by the magnetic detection element 10a.

[0112] On the other hand, in the second state, which is the state when current is supplied, with a current 20c in the direction of Y1 flowing from the control current source I through the control wiring 61 to the spin Hall layer 20, spin injection occurs from the spin Hall layer 20 to the anisotropic variable layer 40, similar to the case of Example 1-1. As a result, a spin orbit torque is generated in the anisotropic variable layer 40, and as shown in Figure 14A, the magnetization 40m of the anisotropic variable layer 40 aligns in the direction of Y2. Since the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled, the magnetization 13m of the free magnetic layer 13 also aligns in the direction of Y2.

[0113] Since the directions of these magnetizations, 40m and 13m, are in the XY plane direction perpendicular to the thickness of the anisotropic variable layer 40 and the free magnetic layer 13, the direction of the magnetization 40m of the anisotropic variable layer 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. In other words, the anisotropic variable layer 40 and the free magnetic layer 13 have a high effective permeability in the X direction.

[0114] When the measurement magnetic field H is applied in this state, as shown in Figure 14B, the magnetization 40m of the anisotropic variable layer 40 rotates to align with the measurement magnetic flux Φ and aligns with X1, thereby concentrating the measurement magnetic flux Φ in the anisotropic variable layer 40. Here, since the anisotropic variable layer 40 is magnetically coupled with the free magnetic layer 13, the magnetic flux oriented towards X1, which has a higher density than in the first state (Figure 13B), reaches the free magnetic layer 13 under the influence of the magnetization 40m of the anisotropic variable layer 40.

[0115] Thus, 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 direction of X1 than in the first state. Therefore, the measurement sensitivity of the measurement magnetic field H of the magnetic detection element 10a is relatively higher in the second state. Consequently, by subtracting the first output from the second output in the magnetic field calculation unit 4, a measurement signal with 1 / f noise appropriately removed can be obtained.

[0116] In Examples 1-1 and 1-2, in the first state, the magnetization 40m of the anisotropic variable layer 40 is oriented Z1, with the exchange coupling 20af with the spin Hall layer 20 acting as the bias magnetic field source. However, the bias magnetic field source that aligns the magnetization 40m of the anisotropic variable layer 40 to a predetermined direction in the first state is not limited to this. The magnetization 40m of the anisotropic variable layer 40 may be oriented in the Z direction with the induced magnetic field from the current-carrying coil or the magnetic field from the permanent magnet acting as the bias magnetic field. Even in such cases, in the second state, the magnetization 40m of the anisotropic variable layer 40 should be oriented in the Y direction based on the application of current to the spin Hall layer 20. From the viewpoint of increasing the correlation between the noise components in the first signal and the noise components in the second signal, it is sometimes 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.

[0117] (Example 2-1) Figure 15A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of a magnetic sensor according to Example 2-1, which has a variable magnetic field detection unit of type B and a configuration of the first embodiment (the anisotropic variable layer and the magnetosensitive part of the magnetic detection element are magnetically uncoupled). Figure 15B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 2-1. Figure 16A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 2-1. Figure 16B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 2-1. In Figures 15B and 16B, the wiring and other elements shown in Figures 15A and 16A are omitted from the display.

[0118] The variable magnetic field detection unit 100a according to Example 2-1 has a non-magnetic member 41, similar to the variable magnetic field detection unit 100a according to Example 1-1, and the anisotropic variable layer 40 and the free magnetic layer 13 are not magnetically coupled. Furthermore, the variable magnetic field detection unit 100a according to Example 2-1 differs from the variable magnetic field detection unit 100a according to Example 1-1 in that the control wiring 61 is provided so that the current from the control current source I, which is part of the control power supply 3, is applied to the spin Hall layer 20 in the X direction (Y direction in Example 1-1).

[0119] In the first state, a current 20c in the X direction, specifically in the X1 direction, is passed from the control current source I through the control wiring 61 to the spin Hall layer 20 to energize it. The application of current causes spin injection from the spin Hall layer 20 to the anisotropic variable layer 40, generating a spin orbit torque in the anisotropic variable layer 40, similar to Example 1-1. As shown in Figure 15A, the magnetization 40m of the anisotropic variable layer 40 is strongly aligned in the Y2 direction. In the variable magnetic field detection unit 100a according to Example 2-1, the magnetic field 21m is in the Y1 direction, and a bias magnetic field source 21, made of a permanent magnet or the like, is stacked on the Z2 side relative to the spin Hall layer 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 spin Hall layer 20, magnetization 40m in the Y2 direction is generated based on this bias magnetic field source 21 (see Figure 16A).

[0120] Therefore, even when the measurement magnetic flux Φ is applied to the anisotropic variable layer 40, the magnetization 40m of the anisotropic variable layer 40 does not easily rotate along the X direction, as shown in Figure 15B. That is, the anisotropic variable layer 40 has a low effective permeability μ1 in the X direction, which is equivalent to the permeability μ0 of the surrounding insulator 50. Therefore, the anisotropic variable layer 40 does not easily affect the measurement magnetic flux Φ that reaches the free magnetic layer 13 of the magnetic detection element 10a, and the measurement of the measurement magnetic flux Φ is performed in the magnetic detection element 10a in the same magnetic environment as when the anisotropic variable layer 40 is absent (replaced by the insulator 50).

[0121] On the other hand, in the second state, the application of current 20c to the spin Hall layer 20 is stopped, resulting in a de-energized state. As a result, as shown in Figure 16A, the spin Hall layer 20 no longer controls the direction of the magnetization 40m of the anisotropic variable layer 40. Therefore, although the magnetic field 21m of the bias magnetic field source 21 aligns the magnetization 40m of the anisotropic variable layer 40 to the Y2 direction, the degree of alignment is weaker than in the first state. Consequently, when the anisotropic variable layer 40 receives a measured magnetic flux Φ in the X1 direction, its magnetization 40m easily rotates in the XY plane and becomes oriented to X1. Therefore, the effective permeability μ2 of the anisotropic variable layer 40 in the X direction in the second state is higher than the permeability μ0 of the surrounding insulator 50.

[0122] When a measurement magnetic field H is applied in this state, as shown in Figure 16B, the magnetization 40m of the anisotropic variable layer 40 rotates to align with the measurement magnetic flux Φ and faces X1, causing the measurement magnetic flux Φ to concentrate in the anisotropic variable layer 40. As a result, the density of the measurement magnetic flux Φ reaching 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.

[0123] Thus, in Example 2-1, the measured magnetic flux Φ reaches the magnetic detection element 10a more easily in the first state than in the second state. Therefore, by subtracting the second output from the first output in the magnetic field calculation unit 4, a measurement signal with 1 / f noise appropriately removed can be obtained.

[0124] (Example 2-2) Figure 17A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of a magnetic sensor according to Example 2-2, which has a variable magnetic field detection unit of type B and a configuration of the second embodiment (the anisotropic variable layer 40 and the magnetosensitive part of the magnetic detection element are magnetically coupled). Figure 17B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 2-2. Figure 18A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 2-2. Figure 18B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 2-2. In Figures 17B and 18B, the wiring and other elements shown in Figures 17A and 18A are omitted from the display.

[0125] The variable magnetic field detection unit 100a according to Example 2-2 differs from the variable magnetic field detection unit 100a according to Example 2-1 in that it does not have a non-magnetic member 41, but the other configurations are the same. For this reason, in the variable magnetic field detection unit 100a according to Example 2-2, the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled. Therefore, as shown in Figure 17A, in the first state in which current 20c flows from the control current source I through the control wiring 61 to the spin Hall layer 20 in the direction of X1, a spin orbit torque is generated in the anisotropic variable layer 40, causing the magnetization 40m of the anisotropic variable layer 40 to be strongly aligned in the direction of Y2, and the magnetization 13m of the free magnetic layer 13, which is magnetically coupled to the anisotropic variable layer 40, is also strongly aligned in the direction of Y2.

[0126] Therefore, even when the measurement magnetic flux Φ is applied to the anisotropic variable layer 40, the magnetization 40m of the anisotropic variable layer 40 does not easily rotate along the X direction, as shown in Figure 17B. That is, the anisotropic variable layer 40 has a low effective permeability μ1 in the X direction, which is equivalent to the permeability μ0 of the surrounding insulator 50. Furthermore, in Example 2-2, the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled, so the free magnetic layer 13 also has a low effective permeability in the X direction. Therefore, the free magnetic layer 13 does not easily magnetize in the X1 direction even when subjected to the measurement magnetic flux Φ, resulting in a decrease in the measurement sensitivity of the measurement magnetic field H in the variable magnetic field detection unit 100a.

[0127] On the other hand, in the second state, the application of current 20c to the spin Hall layer 20 is stopped, resulting in a de-energized state. As a result, as shown in Figure 18A, the spin Hall layer 20 no longer controls the direction of the magnetization 40m of the anisotropic variable layer 40. In Example 2-2, since the bias magnetic field source 21, which is made of a permanent magnet or the like, is stacked on the Z2 side relative to the spin Hall layer 20, the magnetization 40m of the anisotropic variable layer 40 is aligned to the Y2 direction by the magnetic field 21m generated by the bias magnetic field source 21, but to a weaker degree than in the first state. Therefore, the effective permeability in the X direction of the anisotropic variable layer 40 and the free magnetic layer 13 magnetically coupled thereto in the second state is higher than the permeability μ0 of the surrounding insulator 50.

[0128] When the measurement magnetic field H is applied in this state, as shown in Figure 18B, the magnetization 40m of the anisotropic variable layer 40 rotates to align with the measurement magnetic flux Φ and become oriented towards X1, thereby concentrating the measurement magnetic flux Φ in the anisotropic variable layer 40. Here, since the anisotropic variable layer 40 is magnetically coupled with the free magnetic layer 13, the magnetic flux oriented towards X1 with a higher density than in the first state (Figure 17B) reaches the free magnetic layer 13 under the influence of the magnetization 40m of the anisotropic variable layer 40.

[0129] Thus, 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 direction of X1 than in the first state. Therefore, the measurement sensitivity of the measurement magnetic field H of the magnetic detection element 10a is relatively higher in the second state. For this reason, by subtracting the first output from the second output in the magnetic field calculation unit 4, a measurement signal with 1 / f noise appropriately removed can be obtained.

[0130] In the embodiments (Embodiments 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 also be a magnetic field based on exchange coupling or an induced magnetic field from an energizing coil, and any component that provides these magnetic fields can be the bias magnetic field source 21. Also, in the first state, current was applied to the spin Hall layer 20 in the X1 direction, but it may also be in the X2 direction. As a result, the magnetization 40m of the anisotropic variable layer 40 is in the Y1 direction, but even in this case, the magnetization 40m is less likely to rotate even when subjected to a measured magnetic flux Φ with a large component in the X1 direction.

[0131] In the second state, the bias magnetic field applied to the anisotropic variable layer 40 was directed in the Y2 direction, but is not limited to this. It is sufficient that the anisotropic variable layer 40 is magnetized in a direction that is easily magnetized by the measured magnetic flux Φ, and from this viewpoint, it may be preferable that the direction of the bias magnetic field is in the in-plane direction of the XY plane. Since the measured magnetic flux Φ has the largest component in the X1 direction, from the viewpoint of reducing hysteresis, it may be preferable that the bias magnetic field is along the X direction, that is, in the X1 direction or the X2 direction.

[0132] (Example 3-1) Figure 19A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of a magnetic sensor according to Example 3-1, which has a variable magnetic field detection unit of type C and a configuration of the first embodiment (the anisotropic variable layer 40 and the magnetosensitive part of the magnetic detection element are magnetically uncoupled). Figure 19B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 3-1. Figure 20A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 3-1. Figure 20B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 3-1. In Figures 19B and 20B, the wiring and other elements shown in Figures 19A and 20A are omitted from the display.

[0133] The variable magnetic field detection unit 100a according to Example 3-1, like the variable magnetic field detection unit 100a according to Example 1-1, has a non-magnetic member 41, and the anisotropic variable layer 40 and the free magnetic layer 13 are not magnetically coupled. On the other hand, a common feature is that control wiring 61 is provided so that current from the control current source I, which is part of the control power supply 3, can be applied to the spin Hall layer 20 in the Y direction.

[0134] In the first state, a current 20c in the Y direction, specifically in the Y1 direction, is passed from the control current source I through the control wiring 61 to the spin Hall layer 20 to energize it. Due to the application of current, spin injection occurs from the spin Hall layer 20 to the anisotropic variable layer 40, and as in Example 1-1, a spin orbit torque is generated in the anisotropic variable layer 40, and as shown in Figure 19A, the magnetization 40m of the anisotropic variable layer 40 is strongly aligned in the Z1 direction.

[0135] When the anisotropic variable layer 40 is aligned in the thickness direction (Z direction) in this way, its magnetization 40m does not change easily. Therefore, even when the measurement magnetic flux Φ is applied to the anisotropic variable layer 40, as shown in Figure 19B, the magnetization 40m of the anisotropic variable layer 40 does not easily rotate along the X direction. That is, the anisotropic variable layer 40 has a low effective permeability μ1 in the X direction, which is equivalent to the permeability μ0 of the surrounding insulator 50. Therefore, the anisotropic variable layer 40 does not easily affect the measurement magnetic flux Φ that reaches the free magnetic layer 13 of the magnetic detection element 10a, and the measurement of the measurement magnetic flux Φ is performed in the magnetic detection element 10a in the same magnetic environment as when the anisotropic variable layer 40 is absent (replaced by the insulator 50).

[0136] On the other hand, in the second state, the application of current 20c to the spin Hall layer 20 is stopped, resulting in a de-energized state. As a result, as shown in Figure 20A, the spin Hall layer 20 no longer controls the direction of the magnetization 40m of the anisotropic variable layer 40. In Example 3-1, the spin Hall layer 20 is made of an antiferromagnetic material. The exchange coupling 20af of this spin Hall layer 20 functions as a bias magnetic field source, and the anisotropic variable layer 40 is magnetized relatively weakly in the Y2 direction. Therefore, the anisotropic variable layer 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 anisotropic variable layer 40 in the X direction is higher than the permeability μ0 of the surrounding insulator 50.

[0137] When a measurement magnetic field H is applied in this state, as shown in Figure 20B, the magnetization 40m of the anisotropic variable layer 40 rotates to align with the measurement magnetic flux Φ and faces X1, causing the measurement magnetic flux Φ to concentrate in the anisotropic variable layer 40. As a result, the density of the measurement magnetic flux Φ reaching 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.

[0138] Thus, in Example 3-1, the first state allows the measured magnetic flux Φ to reach the magnetic detection element 10a more easily than the second state. Therefore, by subtracting the second output from the first output in the magnetic field calculation unit 4, a measurement signal with 1 / f noise appropriately removed can be obtained.

[0139] (Example 3-2) Figure 21A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of a magnetic sensor according to Example 3-2, which has a variable magnetic field detection unit of type C and a configuration of the second embodiment (the anisotropic variable layer 40 and the magnetosensitive part of the magnetic detection element are magnetically coupled). Figure 21B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the first state) of the magnetic sensor according to Example 3-2. Figure 22A is a diagram illustrating the state before a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 3-2. Figure 22B is a diagram illustrating the state after a measurement magnetic field is applied to the variable magnetic field detection unit (the magnetic state of the anisotropic variable layer is in the second state) of the magnetic sensor according to Example 3-2. In Figures 21B and 22B, the wiring and other elements shown in Figures 21A and 22A are omitted from the display.

[0140] The variable magnetic field detection unit 100a according to Example 3-2 differs from the variable magnetic field detection unit 100a according to Example 3-1 in that it does not have a non-magnetic member 41, but the other configurations are the same. For this reason, in the variable magnetic field detection unit 100a according to Example 3-2, the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled. Therefore, as shown in Figure 21A, in the first state in which current 20c in the direction of Y1 flows from the control current source I through the control wiring 61 to the spin Hall layer 20, a spin orbit torque is generated in the anisotropic variable layer 40, causing the magnetization 40m of the anisotropic variable layer 40 to align in the direction of Z1, and the magnetization 13m of the free magnetic layer 13, which is magnetically coupled to the anisotropic variable layer 40, is also strongly aligned in the direction of Z1.

[0141] Therefore, even when the measurement magnetic flux Φ is applied to the anisotropic variable layer 40, the magnetization 40m of the anisotropic variable layer 40 does not easily rotate along the X direction, as shown in Figure 21B. That is, the anisotropic variable layer 40 has a low effective permeability μ1 in the X direction, which is equivalent to the permeability μ0 of the surrounding insulator 50. Furthermore, in Example 3-2, the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled, so the free magnetic layer 13 also has a low effective permeability in the X direction. Therefore, the free magnetic layer 13 does not easily magnetize in the X1 direction even when subjected to the measurement magnetic flux Φ, resulting in a decrease in the measurement sensitivity of the measurement magnetic field H in the variable magnetic field detection unit 100a.

[0142] On the other hand, in the second state, the application of current 20c to the spin Hall layer 20 is stopped, resulting in a de-energized state. As a result, as shown in Figure 22A, the spin Hall layer 20 no longer controls the direction of the magnetization 40m of the anisotropic variable layer 40. In Example 3-2, the spin Hall layer 20 has a portion made of antiferromagnetic material, and due to the exchange coupling 20af between this antiferromagnetic material and the anisotropic variable layer 40, the magnetization 40m of the anisotropic variable layer 40 is oriented in the Y2 direction, but the degree of magnetization is relatively weak. Based on this magnetization of the anisotropic variable layer 40, the magnetization 13m of the free magnetic layer 13 that is magnetically coupled to the anisotropic variable layer 40 is also oriented in the Y2 direction, and the degree of magnetization is relatively weak, similar to the magnetization 40m of the anisotropic variable layer 40. For this reason, the anisotropic variable layer 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. In other words, the effective permeability μ2 of the anisotropic variable layer 40 in the X direction is higher than the permeability μ0 of the surrounding insulator 50.

[0143] When the measurement magnetic field H is applied in this state, as shown in Figure 22B, the magnetization 40m of the anisotropic variable layer 40 rotates to align with the measurement magnetic flux Φ and aligns with X1, thereby concentrating the measurement magnetic flux Φ in the anisotropic variable layer 40. Here, the free magnetic layer 13 is magnetically coupled with the anisotropic variable layer 40, and therefore, influenced by the magnetization 40m of the anisotropic variable layer 40, a magnetic flux oriented towards X1 with a higher density than in the first state (Figure 21B) reaches the free magnetic layer 13.

[0144] Thus, 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 direction of X1 than in the first state. Therefore, the measurement sensitivity of the measurement magnetic field H of the magnetic detection element 10a is relatively higher in the second state. Consequently, by subtracting the first output from the second output in the magnetic field calculation unit 4, a measurement signal with 1 / f noise appropriately removed can be obtained.

[0145] In the embodiments (Embodiments 3-1 and 3-2) having the above-described Type C configuration, the exchange coupling 20af served as the bias magnetic field source to apply the bias magnetic field, but the invention is not limited to this. The bias magnetic field may also be a magnetic field from a permanent magnet or an induced magnetic field from an energizing coil, and any component that provides these magnetic fields can be the bias magnetic field source 21. In addition, although the spin Hall layer 20 was energized in the Y1 direction in the first state, it may also be energized in the Y2 direction. As a result, the magnetization 40m of the anisotropic variable layer 40 will be in the Z2 direction, but even in this case, the magnetization 40m is less likely to rotate even when subjected to a measured magnetic flux Φ with a large component in the X1 direction.

[0146] In the second state, the bias magnetic field applied to the anisotropic variable layer 40 was in the direction of Y2, but is not limited to this. The magnetization 40m of the anisotropic variable layer 40, which is set in a predetermined direction by the bias magnetic field, should be in a direction that makes it easy for the anisotropic variable layer 40 to rotate along the direction of the measured magnetic flux Φ when the anisotropic variable layer 40 receives the measured magnetic flux Φ. From this viewpoint, it may be preferable that the bias magnetic field is in the in-plane direction of the XY plane. Since the direction of the component of the measured magnetic flux Φ in the direction of X1 is the largest, from the viewpoint of reducing hysteresis, it may be preferable that the bias magnetic field is along the X direction, that is, in the direction of X1 or X2.

[0147] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit it. Accordingly, 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.

[0148] In the above description, the stacking direction of the anisotropic variable layer 40 and the spin Hall layer 20 in the magnetic control body 60, and the alignment direction of the magnetic sensing element 10a and the magnetic control body 60 were both in the second direction, but this is not limited to this. For example, the anisotropic variable layer 40 and the spin Hall layer 20 may be stacked in the first or third direction. Also, the boundary between the anisotropic variable layer 40 and the spin Hall layer 20 in the magnetic control body 60 was a plane parallel to the XY plane, but this is not limited to this. The surface formed by the boundary may have a portion that is inclined with respect to the XY plane. Specific examples of such cases include a configuration where the boundary is a plane but inclined with respect to the XY plane, a configuration where the boundary is a curved surface, a configuration where the boundary has a bent portion, and a configuration where the boundary forms a pattern when viewed from the stacking direction. Furthermore, the wiring for applying current to the spin Hall layer 20 may be shared with part of the wiring for measuring the electrical characteristics of the magnetic sensing element, thereby simplifying the overall circuit.

[0149] Furthermore, in the above description, the magnetization 40m of the anisotropic variable layer 40 rotates due to the spin orbit torque from the spin Hall layer 20, but this is not limited to this. The magnetization 40m of the anisotropic variable layer 40 may also rotate due to the spin transfer torque, and both the spin orbit torque and the spin transfer torque may contribute to the rotation of the magnetization 40m of the anisotropic variable layer 40.

[0150] Figure 23A illustrates the state of the magnetic sensor according to Example 2-1m, which is another modification of Example 2-1, where the anisotropic variable layer is in the second state and before the measurement magnetic field is applied. Figure 23B illustrates the state of the magnetic sensor according to Example 2-1m, which is another modification of Example 2-1, where the anisotropic variable layer is in the second state and the measurement magnetic field is applied. Figure 24A illustrates the state of the magnetic sensor according to Example 2-2m, which is another modification of Example 2-2, where the anisotropic variable layer is in the second state and before the measurement magnetic field is applied. Figure 24B illustrates the state of the magnetic sensor according to Example 2-2m, which is another modification of Example 2-2, where the anisotropic variable layer is in the second state and the measurement magnetic field is applied. Note that in the drawings from Figure 23A onward, the wiring and other elements shown in Figure 11A and other figures are omitted from the display.

[0151] In Example 2-1, as shown in Figure 15A, by applying current to the spin Hall layer 20 in the X1 direction, the anisotropic variable layer 40 is placed in a first state where the effective permeability in the X direction is relatively low. Furthermore, as shown in Figure 16A, by leaving the spin Hall layer 20 unenergized, the magnetization 40m of the anisotropic variable layer 40 is weakly directed in the Y2 direction based on the magnetic field 21m of the bias magnetic field source 21, placing the anisotropic variable layer 40 in a second state where the effective permeability in the X direction is relatively high.

[0152] In contrast, in Example 2-1m, the control for the second state differs from that of Example 2-1. As shown in Figure 23A, by applying current to the spin Hall layer 20 in the X2 direction, which is opposite to that of the first state, a magnetization 40ma in the Y1 direction, which is opposite to that of the first state in Example 2-1, is generated. Since 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, the magnetization 40m of the anisotropic variable layer 40 in the second state becomes particularly weak. As a result, the anisotropic variable layer 40 in the second state becomes more susceptible to the influence of the measured magnetic flux Φ. Therefore, as shown in Figure 23B, the direction of the magnetization 40m becomes the X1 direction, which is aligned with the measured magnetic flux Φ, and a concentration of the measured magnetic flux Φ occurs in the anisotropic variable layer 40.

[0153] In Example 2-2m, as in Example 2-1m, as shown in Figure 24A, current is passed through the spin Hall layer 20 in the X2 direction, which is opposite to the direction in the first state (see Figure 17A), thereby generating a magnetization 40ma in the Y1 direction, which is opposite to the direction in the first state of Example 2-2. 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. As a result, the magnetization 40m of the anisotropic variable layer 40 in the second state becomes particularly weak, and the anisotropic variable layer 40 in the second state becomes more susceptible to the influence of the measured magnetic flux Φ. Therefore, as shown in Figure 24B, the direction of the magnetization 40m becomes the X1 direction, which is aligned with the measured magnetic flux Φ, and a concentration of the measured magnetic flux Φ occurs in the anisotropic variable layer 40.

[0154] Figure 25 illustrates one modification of the variable magnetic field detection unit 100a according to Example 1-1, and Figure 26 illustrates another modification of the variable magnetic field detection unit 100a according to Example 1-1. Figure 27 illustrates one modification of the variable magnetic field detection unit 100a according to Example 1-2, and Figure 28 illustrates another modification of the variable magnetic field detection unit 100a according to Example 1-2.

[0155] The spin Hall layer 20 shown in Figure 11A has a single-phase structure and has the function of generating an exchange coupling interaction with the anisotropic variable layer 40 in the non-energized state to generate a magnetization 40m in the Z1 direction in the anisotropic variable layer 40 (exchange coupling function), and the function of generating a spin orbit torque in the energized state to reversibly change the magnetization 40m from the Z1 direction to the Y2 direction (spin torque function). However, the spin Hall layer 20 may have a multi-phase structure consisting of a portion having an exchange coupling function and a portion having a spin torque function. Figure 25 shows a specific example of such a case, in which the spin Hall layer 20 has a structure in which a first modulation section 201 having an exchange coupling function and a second modulation section 202 having a spin torque function are stacked in the Z direction. In this case, the magnetic field based on the exchange coupling 202af between the first modulation section 201 and the second modulation section 202 becomes the bias magnetic field. Because the spin Hall layer 20 has such a structure, a material that does not have the function of generating spin orbit torque can be used as the constituent material of the first modulation section 201, and a material other than an antiferromagnetic material can be used as the constituent material of the second modulation section 202.

[0156] The exchange coupling interaction is not limited to the spin Hall layer 20 and the anisotropic variable layer 40; the portion of the anisotropic variable layer 40 made of ferromagnet and the portion that generates the exchange coupling interaction may be part of the anisotropic variable layer 40. Figure 26 shows a specific example of such a case, in which the anisotropic variable layer 40 has a structure in which a first variable portion 401 made of ferromagnet and a second variable portion 402 having an exchange coupling function are stacked in the Z direction. In this case, the magnetic field based on the exchange coupling 402af between the first variable portion 401 and the second variable portion 402 becomes the bias magnetic field. By having such a structure in the anisotropic variable layer 40, materials other than antiferromagnets can be used as the constituent material of the spin Hall layer 20.

[0157] The same applies when, as shown in Figure 13A, no non-magnetic member 41 is provided between the magnetic control body 60 and the magnetic sensing element 10a, and the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled. The spin Hall layer 20 may have a structure in which a first modulation section 201 having an exchange coupling function and a second modulation section 202 having a spin torque function are stacked in the Z direction, as shown in Figure 27. Alternatively, the anisotropic variable layer 40 may have a structure in which a first variable section 401 made of a ferromagnetic material and a second variable section 402 having an exchange coupling function are stacked in the Z direction, as shown in Figure 28.

[0158] Figure 29 illustrates one modification of the variable magnetic field detection unit 100a according to Example 2-1 and Example 3-1, and Figure 30 illustrates another modification of the variable magnetic field detection unit 100a according to Example 2-1 and Example 3-1. Figure 31 illustrates one modification of the variable magnetic field detection unit 100a according to Example 2-2 and Example 3-2, and Figure 32 illustrates another modification of the variable magnetic field detection unit 100a according to Example 2-2 and Example 3-2.

[0159] As shown in Figure 16A, in Example 2-1, a permanent magnet layer is provided as the bias magnetic field source 21, but as in Example 1-1, the exchange coupling interaction may also be used as the bias magnetic field source. In that case, when the measurement magnetic field H is not applied and the spin Hall layer is not energized, the state is as shown in Figure 20A, similar to Example 3-1. When Example 3-1 uses the exchange coupling interaction as the bias magnetic field source, similar to Example 2-1, the portion where the exchange coupling interaction occurs is not limited to the configuration shown in Figure 16A (single-phase spin Hall layer 20 and single-phase anisotropic variable layer 40). The spin Hall layer 20 may have a structure in which a first modulation section 201 having an exchange coupling function and a second modulation section 202 having a spin torque function are stacked in the Z direction, as shown in Figure 29. In this case, the magnetic field based on the exchange coupling 202af between the first modulation section 201 and the second modulation section 202 becomes the bias magnetic field. Alternatively, the anisotropic variable layer 40 may have a structure in which a first variable part 401 made of a ferromagnetic material and a second variable part 402 having an exchange coupling function are stacked in the Z direction, as shown in Figure 30. In this case, the magnetic field based on the exchange coupling 402af between the first variable part 401 and the second variable part 402 becomes the bias magnetic field.

[0160] The same applies when a non-magnetic member 41 is not provided between the magnetic control body 60 and the magnetic sensing element 10a, and the anisotropic variable layer 40 and the free magnetic layer 13 are magnetically coupled. In Example 2-2, the exchange coupling interaction may be used as the bias magnetic field source instead of the permanent magnet layer. In that case, when the measurement magnetic field H is not applied and the spin Hall layer is not energized, the state is as shown in Figure 22A, similar to Example 3-2. The spin Hall layer 20 may have a structure in which a first modulation section 201 having an exchange coupling function and a second modulation section 202 having a spin torque function are stacked in the Z direction, as shown in Figure 31. In this case, the magnetic field based on the exchange coupling 202af between the first modulation section 201 and the second modulation section 202 becomes the bias magnetic field. Alternatively, the anisotropic variable layer 40 may have a structure in which a first variable section 401 made of a ferromagnetic material and a second variable section 402 having an exchange coupling function are stacked in the Z direction, as shown in Figure 32. At this time, the magnetic field based on the exchange coupling 402af between the first variable unit 401 and the second variable unit 402 becomes the bias magnetic field.

[0161] When the bias magnetic field source 21 is a permanent magnet or a coil that generates an induced magnetic field by current, the arrangement relationship between the bias magnetic field source 21 and the anisotropic variable layer 40 is arbitrary. For example, as shown in Figure 15A, they may be arranged along the alignment direction (Z direction, second direction) of the magnetic detection element 10a and the anisotropic variable layer 40, or they may be arranged in a direction having an in-plane component of the XY plane (first plane). A specific example of such a case is shown in Figure 33. Figure 33 is an explanatory diagram of a modified variable magnetic field detection unit according to Embodiment 2-1.

[0162] Unlike the variable magnetic field detection unit 100a shown in Figure 15A, the variable magnetic field detection unit 100a shown in Figure 33 does not have a bias magnetic field source 21 on the Z2 side of the magnetic control body 60. In the variable magnetic field detection unit 100a, the magnetic control body 60, which has a spin Hall layer 20 (not shown) and an anisotropic variable layer 40 (not shown), has a length in the Y direction, which is one of the in-plane directions of the first XY plane, that is longer than the lengths in the other directions. Therefore, due to shape magnetic anisotropy, the anisotropic variable layer 40 (not shown) has an easy magnetization direction in the Y direction. The free magnetic layer 13 (not shown) of the magnetic detection element 10a also has an easy magnetization direction in the Y direction due to shape magnetic anisotropy, similar to the anisotropic variable layer 40 (not shown). It is also possible to position this shape magnetic anisotropy as a bias magnetic field source. If the anisotropic variable layer 40 (not shown) has crystalline magnetic anisotropy, this magnetic anisotropy can also be a bias magnetic field source 21. Furthermore, in the variable magnetic field detection unit 100a shown in Figure 31, bias magnetic field sources 211 and 212, each having a permanent magnet or a coil that generates an induced magnetic field, are provided on both sides of the magnetic control body 60 in the Y direction, generating magnetic fields 211m and 212m in the Y2 direction, respectively. Due to these magnetic fields, the magnetization 40m of the anisotropic variable layer 40 (not shown) is directed in the Y2 direction.

[0163] Since the anisotropic variable layer 40 according to this embodiment has a portion made of ferromagnetic material, the direction of the magnetization 40m (bias magnetic field) of the anisotropic variable layer 40 when the spin Hall layer is not energized may be set by the remanent magnetization of this portion. For example, in the configuration shown in Figure 33, the members indicated by reference numerals 211 and 212 are coils, and by energizing the coils, magnetic fields 211m and 212m in the Y2 direction are generated as shown in Figure 33, and after aligning the magnetization 40m of the anisotropic variable layer 40 to the Y2 direction with these magnetic fields, the energization of the coils may be stopped. When the energization of the coils is stopped, the magnetic fields 211m and 212m disappear, but if magnetization 40m in the Y2 direction exists as remanent magnetization in the anisotropic variable layer 40, this remanent magnetization becomes the bias magnetic field of the anisotropic variable layer 40.

[0164] The present invention is useful as a magnetic sensor and magnetic measurement method with high magnetic resolution that can detect external magnetic fields with high sensitivity.

[0165] 1: Magnetic sensor 2: Magnetic field detection unit 3: Control power supply 4: Magnetic field calculation unit 5: Amplifier 6: A / D conversion circuit 7: Control unit 10P: Detection center 10a, 10b, 10c, 10d: Magnetic detection elements 11: Fixed magnetic layer 11m, 13m, 40m, 40ma, 40mb: Magnetization 12: Intermediate layer 13: Free magnetic layer (magnetic sensing part) 15: Full bridge circuit 20: Spin Hall layer 201: First modulation unit 202: Second modulation unit 20af, 202af, 402af: Exchange coupling 20c: Current 21, 211, 212: Bias magnetic field source 21m, 211m, 212m: Magnetic field 31: First magnetic material 32: Second magnetic material 61: Control wiring 62: Measurement wiring 40: Anisotropic variable layer 401: First variable section 402: Second variable section 41: Non-magnetic material 50: Insulator 60: Magnetic control body 100a, 100b, 100c, 100d: Variable magnetic field detection section 311: First end GND: Ground terminal H: Measured magnetic field I: Control current source V: Measured voltage source V1, V2: Output terminals Vdd: Power terminal Φ: Measured magnetic flux

Claims

1. A magnetic sensor characterized by comprising: a magnetic sensing element having a magnetosensitive portion whose sensitivity axis is aligned along a first direction; an anisotropic variable layer having a portion made of a ferromagnetic material and capable of taking on a first state and a second state in which the magnetic state differs, including at least one of the effective permeability and the direction of magnetization; and a spin Hall layer that changes the magnetic state of the anisotropic variable layer.

2. The magnetic sensor according to claim 1, wherein the magnetic sensing element has different measurement sensitivity for the measurement magnetic field along the first direction when the anisotropic variable layer is in the first state and when it is in the second state.

3. The magnetic sensor according to claim 1, wherein the magnetic sensing element and the anisotropic variable layer are aligned in a second direction perpendicular to the first direction.

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

5. The magnetic sensor according to claim 3, wherein, when viewed in the second direction, both ends of the magnetic sensing element in the first direction overlap with the anisotropic variable layer.

6. The magnetic sensor according to 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 anisotropic variable layer is in a first state and a second output from the variable magnetic field detection unit when the anisotropic variable layer is in a second state.

7. 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 anisotropic variable layer, and the magnetosensitive unit is magnetically uncoupled to the anisotropic variable layer.

8. The magnetic sensor according to claim 1, wherein the magnetic sensing portion is magnetically coupled to the anisotropic variable layer.

9. The magnetic sensor according to claim 8, wherein the magnetic sensing portion and the anisotropic variable layer are integrated in at least a portion thereof.

10. The magnetic sensor according to claim 2, wherein the variable magnetic field detection unit further comprises a magnetic material that is magnetized upon receiving the measurement magnetic field, and the magnetosensitive unit is positioned to measure the magnetic flux including the magnetization of the magnetic material.

11. The magnetic sensor according to claim 10, wherein the magnetic material has a first magnetic material aligned with the magnetic sensing element in the first direction, the magnetic sensing element is located on one side in the first direction from the first end which is one end of the first magnetic material in the first direction, and the anisotropic variable layer has a portion located on one side in the first direction from the first end of the first magnetic material.

12. The magnetic sensor according to claim 11, wherein the magnetic sensing element and the anisotropic variable layer are aligned in a second direction perpendicular to the first direction.

13. The magnetic sensor according to claim 12, wherein the anisotropic variable layer has a portion that is closer to the first magnetic material in the first direction than the detection center of the magnetic detection element.

14. The magnetic sensor according to claim 12, wherein the center of the anisotropic variable layer 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 anisotropic variable layer in the first direction is greater than or equal to the length of the magnetic sensing element in the first direction.

16. The magnetic sensor according to claim 12, wherein the length of the first magnetic material in the first direction is longer than the length in the second direction.

17. The magnetic sensor according to claim 12, wherein the anisotropic variable layer is arranged to be magnetically coupled with the first magnetic material.

18. The magnetic sensor according to claim 11, wherein the magnetic material further comprises a second magnetic material that is distal to the magnetic sensing element in the first direction when viewed from the first end.

19. The magnetic sensor according to claim 18, wherein the anisotropic variable layer is arranged to be magnetically coupled with the first magnetic material and the second magnetic material.

20. The magnetic sensor according to claim 2, wherein the spin Hall layer changes the magnetic state of the anisotropic variable layer based on a change in the state of current flow, and the state of current flow of the spin Hall layer differs when the anisotropic variable layer is in the first state and when it is in the second state.

21. The magnetic sensor according to claim 20, wherein the effective permeability μ2 in the first direction of the anisotropic variable layer in the second state is higher than the effective permeability μ1 in the first direction of the anisotropic variable layer in the first state.

22. The magnetic sensor according to claim 21, wherein the variable magnetic field detection unit has a bias magnetic field source that causes the magnetization of the anisotropic variable layer in the first state to be aligned with an intersecting direction intersecting the first direction to such an extent that the magnetization of the anisotropic variable layer in the first state does not rotate when the measuring magnetic field is applied, and the magnetization of the anisotropic variable layer in the second state is aligned with the in-plane direction of the first plane with a strength that allows it to rotate in the in-plane direction of the first plane, which includes the first direction as one of the in-plane directions, when the measuring magnetic field is applied.

23. The magnetic sensor according to claim 22, wherein the spin Hall layer is in a non-energized state when the anisotropic variable layer is in the first state.

24. The magnetic sensor according to claim 22, wherein the spin Hall layer is energized when the anisotropic variable layer is in the first state.

25. The magnetic sensor according to claim 22, wherein the intersecting direction is perpendicular to the first direction.

26. The magnetic sensor according to claim 22, wherein the anisotropic variable layer is a film-like body, and the intersecting direction is along the thickness direction of the film-like body.

27. The magnetic sensor according to claim 26, wherein the spin Hall layer has a film-like shape, and the anisotropic variable layer and the spin Hall layer are arranged side by side in the intersecting direction.

28. The magnetic sensor according to claim 22, wherein the anisotropic variable layer is a film-like body, and the first surface is parallel to the film surface of the film-like body.

29. The magnetic sensor according to claim 28, wherein the intersecting direction is the in-plane direction of the film surface of the film-like material.

30. The magnetic sensor according to claim 22, wherein the spin Hall layer has a spin torque generating unit that applies a spin orbit torque to the anisotropic variable layer when energized, and the magnetic state of the anisotropic variable layer in the second state is set based on the spin orbit torque from the spin torque generating unit.

31. The magnetic sensor according to claim 30, wherein the magnetization of the anisotropic variable layer in the second state is along the direction of current flow in the spin torque generating unit.

32. The magnetic sensor according to claim 21, wherein the magnetization of the anisotropic variable layer in the first state is magnetized by the spin Hall layer in a cross direction intersecting the first direction to such an extent that the magnetization does not rotate when the measurement magnetic field is applied, and the magnetization of the anisotropic variable layer in the second state is aligned with the in-plane direction of the first plane with sufficient strength to allow rotation in the in-plane direction of the first plane, which includes the first direction as one of the in-plane directions, when the measurement magnetic field is applied.

33. The magnetic sensor according to claim 32, wherein when the anisotropic variable layer is in the first state, the spin Hall layer is energized, and when the anisotropic variable layer is in the second state, the spin Hall layer is not energized.

34. The magnetic sensor according to claim 32, wherein when the anisotropic variable layer is in the first state, the spin Hall layer is energized, and when the anisotropic variable layer is in the second state, the spin Hall layer is energized in a different state than in the first state.

35. The magnetic sensor according to claim 32, wherein the intersecting direction is perpendicular to the first direction.

36. The magnetic sensor according to claim 32, wherein the variable magnetic field detection unit has a bias magnetic field source that causes the magnetization of the anisotropic variable layer to be aligned with the in-plane direction of the first surface to such an extent that the magnetization of the anisotropic variable layer in the second state rotates when the measuring magnetic field is applied.

37. The magnetic sensor according to claim 36, wherein the bias magnetic field source causes the magnetization of the anisotropic variable layer to be aligned in a direction different from the crossing direction and perpendicular to the first direction.

38. The magnetic sensor according to claim 32, wherein the anisotropic variable layer is a film-like body, and the intersecting direction is along the thickness direction of the film-like body.

39. The magnetic sensor according to claim 38, wherein the spin Hall layer has a film-like shape, and the anisotropic variable layer and the spin Hall layer are arranged side by side in the intersecting direction.

40. The magnetic sensor according to claim 32, wherein the anisotropic variable layer is a film-like body, and the intersecting direction is the in-plane direction of the film surface of the film-like body.

41. The magnetic sensor according to claim 32, wherein the anisotropic variable layer is a film-like body, and the first surface is parallel to the film surface of the film-like body.

42. The magnetic sensor according to claim 32, wherein the spin Hall layer has a spin torque generating unit that applies a spin orbit torque to the anisotropic variable layer when energized, and the magnetic state of the anisotropic variable layer in the first state is set based on the spin orbit torque from the spin torque generating unit.

43. The magnetic sensor according to claim 22 or claim 32, wherein when the anisotropic variable layer is in the second state, the direction of current flow to the anisotropic variable layer is along a third direction perpendicular to the first direction in the in-plane direction of the first surface.

44. The magnetic sensor according to claim 22 or claim 36, wherein the anisotropic variable layer has a portion made of a material having crystalline magnetic anisotropy, and the magnetization based on the crystalline magnetic anisotropy becomes the bias magnetic field source.

45. The magnetic sensor according to claim 22 or claim 36, wherein the anisotropic variable layer has shape magnetic anisotropy, and the magnetization based on crystal magnetic anisotropy serves as the bias magnetic field source.

46. ​​The magnetic sensor according to claim 22 or claim 36, wherein when the spin Hall layer is not energized, the anisotropic variable layer is magnetized in a predetermined direction by residual magnetization.

47. The magnetic sensor according to claim 22 or claim 36, wherein the anisotropic variable layer has a portion made of an antiferromagnetic material, and the exchange coupling interaction between the portion made of the ferromagnetic material and the portion made of the antiferromagnetic material becomes the bias magnetic field source.

48. The magnetic sensor according to claim 22 or claim 36, wherein the spin Hall layer has an antiferromagnetic portion made of antiferromagnetism, and the exchange coupling between the antiferromagnetic portion and the anisotropic variable layer serves as the bias magnetic field source.

49. The magnetic sensor according to claim 48, wherein the spin Hall layer comprises a portion made of a material capable of generating spin-orbit torque and a portion made of antiferromagnetism capable of exchanging coupling interaction with the anisotropic variable layer.

50. The magnetic sensor according to claim 48, wherein the spin Hall layer has a portion made of an antiferromagnetic material capable of exchanging coupling interaction with the anisotropic variable layer and generating spin-orbit torque.

51. The magnetic sensor according to claim 22 or 36, 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.

52. The magnetic sensor according to claim 51, wherein the spin Hall layer and the anisotropic variable layer constitute 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 forms a stacked structure with the magnetic control body.

53. The magnetic sensor according to claim 51, wherein the spin Hall layer and the anisotropic variable layer constitute a magnetic control body stacked in a second direction perpendicular to the first direction, the magnetic control body and the magnetic sensing element are arranged along the second direction, and the bias magnetic field source and the magnetic control body are aligned in a direction having an in-plane component of the first surface.

54. The magnetic sensor according to claim 22 or 36, wherein the anisotropic variable layer has at least one of crystalline magnetic anisotropy and shape magnetic anisotropy, and the crystalline magnetic anisotropy and / or the shape magnetic anisotropy serve as the bias magnetic field source.

55. A magnetic measurement method using a magnetic sensor comprising: a variable magnetic field detection unit having a magnetic detection element having a sensitivity axis along a first direction; an anisotropic variable layer having a portion made of a ferromagnetic material and capable of taking on a first state and a second state in which the magnetic state differs, including at least one of effective permeability and magnetization direction; and a spin Hall layer that changes the magnetic state of the anisotropic variable layer; and a magnetic field calculation unit that calculates a measurement magnetic field along a first direction from a first output from the variable magnetic field detection unit when the anisotropic variable layer is in the first state and a second output from the variable magnetic field detection unit when the anisotropic variable layer is in the second state, the method comprising: a first measurement step of obtaining the first output with the anisotropic variable layer in the first state when the measurement magnetic field is applied; a second measurement step of obtaining the second output with the anisotropic variable layer in the second state when the measurement magnetic field is applied; and a magnetic field calculation step of the magnetic field calculation unit calculating the measurement magnetic field from the first output and the second output.

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