Magnetoresistance effect element, magnetic field detector and magnetic sensor system

Abstract

To provide a magnetoresistance effect element capable of isotropically detecting the intensity of an external magnetic field without depending upon the direction of the external magnetic field even with simple constitution.SOLUTION: A magnetoresistance effect element has a lamination structure having a first magnetization free layer, a first nonmagnetic layer and a second magnetization free layer laminated sequentially in a lamination direction, and the outer edge shape of the lamination structure along a plane orthogonal to the lamination direction is isotropic.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to a magnetoresistive effect element, and a magnetic field detection device and a magnetic sensor system including the same. [Background technology]

[0002] In recent years, magnetic sensors using magnetoresistive effect elements have been used in various applications. The magnetoresistive effect element has, for example, a fixed magnetization layer having a fixed magnetization direction, a free magnetization layer having a magnetization direction that can change depending on the direction of an applied magnetic field, and a non-magnetic layer disposed between the fixed magnetization layer and the free magnetization layer.

[0003] Also proposed is a magnetoresistive element that includes, in order, a first magnetic layer having a magnetization whose shape magnetic anisotropy is set in a first reference direction and whose direction changes in response to an external magnetic field, a nonmagnetic layer, and a second magnetic layer having a shape magnetic anisotropy set in a second reference direction intersecting the first reference direction and whose magnetization whose direction changes in response to an external magnetic field, as described in Patent Document 1. Patent Document 1 also discloses a magnetic sensor that detects the strength and direction of an external magnetic field by utilizing changes in the resistance value of the magnetoresistive element in response to changes in the external magnetic field.

[0004] Furthermore, Patent Document 2 proposes a magnetic sensor that includes a magnetic field strength sensor and a magnetic field angle sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-55294 [Patent Document 2] International Publication No. 2020 / 250489 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, it is desirable that a magnetic field detection device equipped with a magnetoresistive effect element has a simpler configuration from the viewpoint of manufacturability and cost reduction.

[0007] Therefore, it is desirable to provide a magnetic field detection device that has a simple configuration and is capable of isotropically detecting the strength of an external magnetic field regardless of the direction of the external magnetic field, and a magnetoresistive element used therein. [Means for solving the problem]

[0008] The magnetoresistive effect element of the present disclosure has a stacked structure in which a first magnetization free layer, a first non-magnetic layer, and a second magnetization free layer are stacked in order in a stacking direction, and the outer edge shape of the stacked structure along a plane perpendicular to the stacking direction is isotropic.

[0009] The magnetic field detection device of the present disclosure includes one or more magnetoresistive effect elements, each of which has a stacked structure in which a first magnetization free layer, a first non-magnetic layer, and a second magnetization free layer are stacked in this order in a stacking direction, and the outer edge shape of the stacked structure along a plane perpendicular to the stacking direction is isotropic.

[0010] The magnetoresistive element of the present disclosure exhibits a resistance value that corresponds to the strength of the in-plane component of the external magnetic field along a plane perpendicular to the stacking direction. The resistance value of this magnetoresistive element changes in response to changes in the strength of the in-plane component of the external magnetic field, but does not depend on the orientation of the in-plane component of the external magnetic field. In other words, the resistance value of the magnetoresistive element changes isotropically in response to changes in the strength of the in-plane component of the external magnetic field, regardless of the orientation of the in-plane component of the external magnetic field. [Effects of the Invention]

[0011] The magnetoresistive element and magnetic field detection device of the present disclosure have a simple configuration and are capable of detecting the strength of an external magnetic field isotropically, regardless of the direction of the external magnetic field. Note that the effects of the present disclosure are not limited to this, and may be any of the effects described below. [Brief explanation of the drawings]

[0012] [Figure 1A] FIG. 1A is a perspective view illustrating the appearance of a magnetoresistive effect element according to a first embodiment of the present disclosure. [Figure 1B] FIG. 1B is a cross-sectional view showing the cross-sectional configuration of the magnetoresistive element shown in FIG. 1A. [Figure 2] FIG. 2 is a characteristic diagram showing the relationship between the magnetic flux density of the external magnetic field applied to the magnetoresistive element shown in FIG. 1A and the resistance value of the magnetoresistive element. [Figure 3] FIG. 3 is an explanatory diagram that schematically shows the relationship between the magnitude of the magnetic flux density of the external magnetic field applied to the magnetoresistive element shown in FIG. 1A and the direction of magnetization. [Figure 4] FIG. 4 is a cross-sectional view illustrating a cross-sectional configuration of a magnetoresistive effect element as a first modified example of the first embodiment of the present disclosure. [Figure 5] FIG. 5 is a characteristic diagram showing the relationship between the magnetic flux density of the external magnetic field applied to the magnetoresistive element shown in FIG. 4 and the resistance value of the magnetoresistive element. [Figure 6] FIG. 6 is an explanatory diagram that schematically shows the relationship between the magnitude of the magnetic flux density of the external magnetic field applied to the magnetoresistive element shown in FIG. 4 and the direction of magnetization. [Figure 7] FIG. 7 is a cross-sectional view illustrating a cross-sectional configuration of a magnetoresistive effect element as a second modified example of the first embodiment of the present disclosure. [Figure 8] FIG. 8 is a perspective view illustrating an appearance of a magnetoresistive effect element according to a third modified example of the first embodiment of the present disclosure. [Figure 9] FIG. 9 is a characteristic diagram showing the relationship between the magnetic flux density of the external magnetic field applied to the magnetoresistive element shown in FIG. 8 and the resistance value of the magnetoresistive element. [Figure 10] FIG. 10 is an explanatory diagram that schematically shows the relationship between the magnitude of the magnetic flux density of the external magnetic field applied to the magnetoresistive element shown in FIG. 8 and the direction of magnetization. [Figure 11] FIG. 11 is a cross-sectional view illustrating a cross-sectional configuration of a magnetoresistive effect element according to a fourth modified example of the first embodiment of the present disclosure. [Figure 12] FIG. 12 is a characteristic diagram showing the relationship between the magnetic flux density of the external magnetic field applied to the magnetoresistive element shown in FIG. 11 and the resistance value of the magnetoresistive element. [Figure 13] FIG. 13 is an explanatory diagram that schematically shows the relationship between the magnitude of the magnetic flux density of the external magnetic field applied to the magnetoresistive element shown in FIG. 11 and the direction of magnetization. [Figure 14] FIG. 14 is a circuit diagram schematically illustrating a circuit configuration of a magnetic field detection device according to the second embodiment of the present disclosure. [Figure 15] FIG. 15 is a characteristic diagram that schematically shows the relationship between the differential output output from the bridge circuit of the magnetic field detection device shown in FIG. 14 and the strength of the external magnetic field. [Figure 16] FIG. 16 is a circuit diagram schematically illustrating a circuit configuration of a magnetic field detection device according to the third embodiment of the present disclosure. [Figure 17] FIG. 17 is a circuit diagram schematically illustrating a circuit configuration of a magnetic field detection device according to the fourth embodiment of the present disclosure. [Figure 18] FIG. 18 is a perspective view schematically illustrating a magnetic sensor system according to the fifth embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The description will be made in the following order: 0.Background 1. First embodiment and its modifications An example of a magnetoresistive element with two magnetization free layers. 2. Second embodiment 1 shows an example of a first magnetic field detection device having a circuit including a magnetoresistive effect element. 3. Third Embodiment 10 is a second example of a magnetic field detection device having a circuit including a magnetoresistive element. 4. Fourth Embodiment 10 is a third example of a magnetic field detection device having a circuit including a magnetoresistive effect element. 5. Fifth Embodiment Examples of applications with magnetic field detection devices.

[0014] <0.Background> Magnetic field angle sensors that detect the direction of an external magnetic field have been widely used. Such magnetic field angle sensors include, for example, a magnetoresistive element in which a free magnetization layer whose magnetization rotates in response to the direction of the external magnetic field and a fixed magnetization layer whose magnetization direction does not change in response to the external magnetic field are stacked via a non-magnetic layer. Such magnetic field angle sensors obtain angular information about the external magnetic field by utilizing the change in the resistance value of the magnetoresistive element that corresponds to the relative angle between the magnetization directions of the free magnetization layer and the fixed magnetization layer.

[0015] However, the magnetic field angle sensor cannot obtain information about the strength of the external magnetic field. Therefore, in order to detect the strength of the external magnetic field, a separate magnetic field strength sensor including a magnetoresistive element or the like must be provided. However, in the case of a magnetoresistive element having a magnetization fixed layer, the relative angle between the magnetization free layer and the magnetization fixed layer needs to be changed depending on the strength of the external magnetic field in the in-plane direction of the stacking, which is perpendicular to the stacking direction. However, the effective magnetic field component that contributes to the above relative angle with respect to the magnetization free layer changes depending on the direction of the external magnetic field. Therefore, it is difficult to obtain strength information in all directions in the in-plane direction of the stacking.

[0016] Therefore, Prior Art Document 1 proposes a magnetoresistive effect element that does not have a magnetization fixed layer. However, the magnetoresistive effect element of Prior Art Document 1 uses two magnetization free layers that have shape magnetic anisotropy in different directions. Therefore, it is necessary to form the two magnetization free layers separately.

[0017] In view of the above circumstances, the present applicant provides a magnetoresistive effect element and a magnetic field sensor that have a simple configuration that is easy to manufacture and can detect the strength of an external magnetic field isotropically, regardless of the direction of the external magnetic field.

[0018] <1. First embodiment> [Configuration of magnetoresistive element 10] First, with reference to Figures 1A and 1B, the configuration of a magnetoresistive effect element 10 according to a first embodiment of the present disclosure will be described. Figure 1A is a perspective view illustrating an example of the external configuration of the magnetoresistive effect element 10. Figure 1B is a cross-sectional view illustrating an example of the cross-sectional configuration of the magnetoresistive effect element 10. The magnetoresistive effect element 10 corresponds to a specific example of a "magnetoresistive effect element" according to one aspect of the present disclosure.

[0019] As shown in FIG. 1A, the magnetoresistive element 10 has a layered structure S10 having a generally cylindrical appearance with a central axis CA. In this specification, the height direction of the magnetoresistive element 10 along the central axis CA is defined as the z-direction, and the radial direction of the generally cylindrical magnetoresistive element 10 perpendicular to the z-direction is defined as the r-direction. Therefore, FIG. 1B shows an example of a cross-sectional configuration along the z-direction. Note that the r-direction represents any in-plane direction perpendicular to the z-direction, and does not represent a specific direction.

[0020] The magnetoresistive element 10 has a stacked structure S10 in which, for example, a first magnetization free layer 11, a nonmagnetic layer 13, and a second magnetization free layer 12 are stacked in this order along the z direction, which is the stacking direction. The outer edge shape of the stacked structure S10 along the stacked surface, which is a plane perpendicular to the z direction, is isotropic. Specifically, the outer edge shape of the stacked structure S10 along the stacked surface, which is a plane perpendicular to the z direction, is circular. Note that the "circular" shape in this disclosure is not limited to a geometrically accurate circle, i.e., a perfect circle, but refers to a circle that allows for unavoidable errors such as manufacturing errors and measurement errors. For example, a small chip, dent, or protrusion may be included in part of the circumference. Furthermore, the "circular" shape in this disclosure may be slightly flattened. Specifically, the ratio of the minimum diameter to the maximum diameter may be 0.9 or more and 1.0 or less. Furthermore, the term "isotropic shape" as used in this disclosure is not limited to a circle, but also includes "regular polygons" such as a regular hexagon or octagon. The term "regular polygon" as used herein is not limited to a geometrically accurate regular polygon, but refers to a regular polygon that allows for unavoidable errors such as manufacturing errors and measurement errors. For example, the outer edge may include slight chips, dents, or protrusions. Furthermore, the lengths of the sides constituting a regular polygon may differ by approximately 10%.

[0021] The first magnetization free layer 11 has a magnetization M11 whose direction changes in response to an external magnetic field. The first magnetization free layer 11 has an easy axis of magnetization along, for example, the z direction. That is, the stable magnetization direction of the first magnetization free layer 11 is parallel to the z direction. Therefore, in the initial state where no external magnetic field is applied, the magnetization M11 is oriented in a direction closer to the z direction than the r direction.

[0022] The second magnetization free layer 12 has a magnetization M12 whose direction changes in response to an external magnetic field. The second magnetization free layer 12 has a hard magnetization axis along, for example, the z direction. That is, the stable magnetization direction of the second magnetization free layer 12 is an in-plane direction perpendicular to the z direction. Therefore, in the initial state when no external magnetic field is applied, the magnetization M12 is oriented in a direction closer to the r direction than the z direction.

[0023] The first magnetization free layer 11 and the second magnetization free layer 12 are both soft ferromagnetic layers and are made of, for example, CoFe, NiFe, or CoFeB. The constituent materials of the first magnetization free layer 11 and the second magnetization free layer 12 may be the same or different. Furthermore, the anisotropy magnetic field strength of the first magnetization free layer 11 and the anisotropy magnetic field strength of the second magnetization free layer 12 may be different from each other.

[0024] When the stacked structure S10 has a magnetic tunnel junction (MTJ) structure, the nonmagnetic layer 13 is a nonmagnetic tunnel barrier layer made of a metal oxide such as magnesium oxide (MgO). When the nonmagnetic layer 13 is a tunnel barrier layer, the nonmagnetic layer 13 has a thickness thin enough to allow a tunnel current based on quantum mechanics to pass through. Alternatively, the nonmagnetic layer 13 may be a nonmagnetic conductive layer made of a platinum group element such as ruthenium (Ru) or gold (Au) or a nonmagnetic metal such as copper (Cu). In this case, the stacked structure S10 is a giant magnetoresistive effect (GMR) film.

[0025] The magnetoresistive element 10 is a CPP (Current Perpendicular to Plane) type magnetoresistive element in which a current for signal detection flows in a direction substantially perpendicular to the stacking plane of the first magnetization free layer 11, the non-magnetic layer 13, and the second magnetization free layer 12 that constitute the magnetoresistive element 10. When a current flows in the z direction in the magnetoresistive element 10 with an external magnetic field applied, the magnetoresistive element 10 exhibits a resistance value according to the external magnetic field. When the external magnetic field applied to the magnetoresistive element 10 changes, the resistance value of the magnetoresistive element 10 also changes.

[0026] A first connection terminal T1 is connected to the first magnetization free layer 11 via a wiring W1. A second connection terminal T2 is connected to the second magnetization free layer 12 via a wiring W2. In the magnetoresistive effect element 10, a current flows in the z direction when a voltage is applied between the first connection terminal T1 and the second connection terminal T2.

[0027] [Behavior of the magnetoresistive element 10] Next, the behavior of the magnetoresistive effect element 10 will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a characteristics diagram showing the relationship between the magnetic flux density B (horizontal axis) of an external magnetic field applied to the magnetoresistive effect element 10 and the resistance value R (vertical axis) of the magnetoresistive effect element 10 when a current is passed through the magnetoresistive effect element 10 in the z direction. Fig. 3 is an explanatory diagram that schematically shows the behavior of the magnetoresistive effect element 10 when an external magnetic field is applied, specifically, how the magnetizations M11 and M12 change depending on the magnitude of the magnetic flux density B of the external magnetic field applied to the magnetoresistive effect element 10.

[0028] (A) of FIG. 3 shows the orientation of magnetization M11 and M12 when magnetic flux density B = -B3 in the characteristic diagram shown in FIG. 2. (B) of FIG. 3 shows the orientation of magnetization M11 and M12 when magnetic flux density B = -B2 in the characteristic diagram shown in FIG. 2. (C) of FIG. 3 shows the orientation of magnetization M11 and M12 when magnetic flux density B = -B1 in the characteristic diagram shown in FIG. 2. (D) of FIG. 3 shows the orientation of magnetization M11 and M12 when magnetic flux density B = B1 in the characteristic diagram shown in FIG. 2. (E) of FIG. 3 shows the orientation of magnetization M11 and M12 when magnetic flux density B = B2 in the characteristic diagram shown in FIG. 2. (F) of FIG. 3 shows the orientation of magnetization M11 and M12 when magnetic flux density B = B3 in the characteristic diagram shown in FIG. 2. The absolute values ​​of B1 and -B1 are equal, the absolute values ​​of B2 and -B2 are equal, and the absolute values ​​of B3 and -B3 are equal. The lengths and directions of the white arrows in (A) to (F) of FIG. 3 indicate the strength and direction of the external magnetic field applied to the magnetoresistive element 10. That is, the longer the white arrow, the stronger the strength of the external magnetic field. (A) to (C) of FIG. 3 indicate that the external magnetic field is applied to the magnetoresistive element 10 in the left direction on the paper, while (D) to (F) of FIG. 3 indicate that the external magnetic field is applied to the magnetoresistive element 10 in the right direction on the paper. The directions of the magnetizations M11 and M12 when the magnetic flux density B=0 in the characteristic diagram shown in FIG. 2 are as shown in FIG. 1B.

[0029] 2 and 3, the direction of the magnetization M11 of the first magnetization free layer 11 changes depending on the magnitude of the magnetic flux density B. In contrast, the second magnetization free layer 12 is easily magnetically saturated by the application of an external magnetic field, and the direction of the magnetization M12 of the second magnetization free layer 12 approaches the direction of the applied external magnetic field regardless of the magnitude of the magnetic flux density B. Furthermore, the resistance value R of the magnetoresistive effect element 10 becomes the maximum resistance value Rmax when the magnetic flux density B=0. This is because, when the magnetic flux density B=0, the direction of the magnetization M11 of the first magnetization free layer 11 is approximately parallel to the z direction, and therefore the angle formed by the direction of the magnetization M11 and the direction of the magnetization M12, which is stable in the +r direction (or −r direction) perpendicular to the z direction, becomes the maximum (i.e., 90°).

[0030] Furthermore, as the absolute value of the magnetic flux density B increases from 0, the resistance value R of the magnetoresistive element 10 gradually decreases and eventually approaches a constant value (R=R3). That is, the resistance value R1 is lower than the resistance value Rmax, the resistance value R2 is lower than the resistance value R1, and the resistance value R3 is lower than the resistance value R2. This is because, as the magnetic flux density B increases, the direction of the magnetization M11 of the first magnetization free layer 11 gradually tilts from a state substantially parallel to the z direction and approaches parallel to the +r direction (or −r direction).

[0031] [Effect of magnetoresistive element 10] In this way, the magnetoresistive element 10 changes its resistance value according to the strength (magnetic flux density) of the applied external magnetic field. Therefore, by knowing in advance the correlation between the strength (magnetic flux density) of the external magnetic field and the resistance value, it is possible to calculate the strength of the external magnetic field by detecting the change in the resistance value of the magnetoresistive element 10. In the magnetoresistive element 10, the outer edge shape of the stacked structure S10 along the stacked plane perpendicular to the z direction is circular, so that the strength of the external magnetic field can be detected isotropically, regardless of the direction of the external magnetic field.

[0032] [Modification of the first embodiment] (First Modification) FIG. 4 is a cross-sectional view illustrating a cross-sectional configuration example of a magnetoresistive effect element 10A as a first modified example of the first embodiment of the present disclosure (hereinafter referred to as modified example 1-1). FIG. 4 corresponds to FIG. 1B illustrating the magnetoresistive effect element 10 of the first embodiment. In the stacked structure S10 of the magnetoresistive effect element 10 of the first embodiment, the orientation of the magnetization M11 of the first magnetization free layer 11 in the initial state is approximately parallel to the z direction, and the orientation of the magnetization M12 of the second magnetization free layer 12 in the initial state is approximately parallel to the r direction. In contrast, in the stacked structure S10A of the magnetoresistive effect element 10A as modified example 1-1, the orientation of the magnetization M12 of the second magnetization free layer 12 in the initial state is approximately parallel to the z direction. Therefore, in the stacked structure S10A of the magnetoresistive effect element 10A, both the first magnetization free layer 11 and the second magnetization free layer 12 have easy axes of magnetization aligned along the z direction. However, the orientation of magnetization M11 in the initial state is approximately parallel to the +z direction, while the orientation of magnetization M12 in the initial state is approximately parallel to the -z direction. That is, in the magnetoresistive effect element 10A, the orientations of magnetization M11 and M12 are approximately antiparallel to each other in the initial state. Except for this point, the configuration of magnetoresistive effect element 10A is substantially the same as the configuration of magnetoresistive effect element 10.

[0033] Fig. 5 is a characteristics diagram showing the relationship between the magnetic flux density B (horizontal axis) of the external magnetic field applied to the magnetoresistive effect element 10A and the resistance value RA (vertical axis) of the magnetoresistive effect element 10A when a current is passed through the magnetoresistive effect element 10A in the z direction. Fig. 6 is an explanatory diagram schematically showing the behavior of the magnetoresistive effect element 10A when an external magnetic field is applied, specifically, how the magnetizations M11 and M12 change depending on the magnitude of the magnetic flux density B of the external magnetic field applied to the magnetoresistive effect element 10A. Figs. 5 and 6 correspond to Figs. 2 and 3, respectively, which show the characteristics and explanatory diagrams of the magnetoresistive effect element 10 of the first embodiment.

[0034] 5 and 6, the magnetoresistive effect element 10A also behaves in the same manner as the magnetoresistive effect element 10 of the first embodiment with respect to an applied external magnetic field. For example, the resistance value RA of the magnetoresistive effect element 10A becomes a maximum resistance value RAmax when the magnetic flux density B=0. However, the maximum resistance value RAmax of the magnetoresistive effect element 10A is greater than the maximum resistance value Rmax of the magnetoresistive effect element 10. This is because, when the magnetic flux density B=0, the direction of the magnetization M11 of the first magnetization free layer 11 becomes substantially parallel to the +z direction and the direction of the magnetization M12 of the second magnetization free layer 12 becomes substantially parallel to the −z direction, so that the angle formed between the direction of the magnetization M11 and the direction of the magnetization M12 is approximately 180°.

[0035] Furthermore, as the absolute value of the magnetic flux density B increases from 0, the resistance value RA of the magnetoresistive effect element 10A gradually decreases and eventually approaches a constant value (R=RA3). That is, the resistance value RA1 is lower than the resistance value RAmax, the resistance value RA2 is lower than the resistance value RA1, and the resistance value RA3 is lower than the resistance value RA2. This is because, as the magnetic flux density B increases, the direction of the magnetization M11 of the first magnetization free layer 11 gradually tilts from a state substantially parallel to the z direction and approaches parallel to the +r direction (or -r direction).

[0036] In this way, the resistance value of the magnetoresistive element 10A also changes according to the strength (magnetic flux density) of the applied external magnetic field. Therefore, by knowing the correlation between the strength (magnetic flux density) of the external magnetic field and the resistance value in advance, it is possible to calculate the strength of the external magnetic field by detecting the change in the resistance value of the magnetoresistive element 10A.

[0037] (Second Modification) FIG. 7 is a cross-sectional view illustrating a cross-sectional configuration example of a magnetoresistive effect element 10B as a second modified example of the first embodiment of the present disclosure (hereinafter referred to as modified example 1-2). FIG. 7 corresponds to FIG. 1B illustrating the magnetoresistive effect element 10 of the first embodiment. The magnetoresistive effect element 10B as modified example 1-2 includes a stacked structure S10B instead of the stacked structure S10. Except for this point, the configuration of the magnetoresistive effect element 10B is substantially the same as the configuration of the magnetoresistive effect element 10 of the first embodiment. In addition to the stacked structure S10, the stacked structure S10B further includes a nonmagnetic layer 15 and a magnetization fixed layer 14 stacked in this order on the opposite side of the nonmagnetic layer 13 from the second magnetization free layer 12.

[0038] The nonmagnetic layer 15 is, for example, a tunnel barrier layer or a nonmagnetic conductive layer, similar to the nonmagnetic layer 13. Therefore, the nonmagnetic layer 15 can be made of the same material as the nonmagnetic layer 13. The nonmagnetic layer 15 is a specific example corresponding to a "second nonmagnetic layer" according to one aspect of the present disclosure.

[0039] The magnetization fixed layer 14 is a ferromagnetic layer whose magnetization is fixed in a specific direction and does not change due to an external magnetic field. In the example shown in FIG. 7, the magnetization M14 is shown fixed to the left of the page, but the direction is not limited to that shown in FIG. 7. The magnetization fixed layer 14 is made of a ferromagnetic material such as Co (cobalt), CoFe (cobalt-iron alloy), or CoFeB (cobalt-iron-boron alloy). In the stacked structure S10B, an antiferromagnetic layer may be provided on the opposite side of the nonmagnetic layer 15 so as to be adjacent to the magnetization fixed layer 14. Such an antiferromagnetic layer is made of an antiferromagnetic material such as a platinum-manganese alloy (PtMn) or an iridium-manganese alloy (IrMn).

[0040] The stacked structure S10B can be considered as a stack of a magnetic field intensity information detector and a magnetic field angle information detector stacked in the z direction. Therefore, by applying a voltage between the connection terminals T1 and T2 and passing a current through the stacked structure S10B in the z direction, a change in resistance value corresponding to the strength of the external magnetic field and a change in resistance value corresponding to the direction of the external magnetic field are detected from the stacked structure S10B. Specifically, the stacked portion S10B1 of the first magnetization free layer 11, the nonmagnetic layer 13, and the second magnetization free layer is a magnetic field intensity information detector that indicates a resistance value that changes depending on the strength of the external magnetic field. The stacked portion S10B2 of the second magnetization free layer 12, the nonmagnetic layer 15, and the magnetization fixed layer 14 is a magnetic field angle information detector that indicates a resistance value that changes depending on the angle of the external magnetic field. When the direction of the external magnetic field rotates in the in-plane direction of the stacked layers, which is perpendicular to the z direction, the direction of the magnetization M12 of the second magnetization free layer 12 rotates to match the direction of the external magnetic field. Therefore, when the direction of the external magnetic field changes, the angle between the direction of the magnetization M12 and the direction of the magnetization M14 changes, and the stacked portion S10B2 exhibits a resistance value that corresponds to the direction of the external magnetic field.

[0041] In this way, the magnetoresistance effect element 10B can detect both the strength information of the external magnetic field and the angle information of the external magnetic field from the integrated stacked structure S10B.

[0042] (Third Modification) FIG. 8 is a perspective view illustrating the appearance of a magnetoresistive effect element 10C as a third modified example (hereinafter referred to as modified example 1-3) of the first embodiment of the present disclosure. FIG. 8 corresponds to FIG. 1A illustrating the magnetoresistive effect element 10 of the first embodiment. The magnetoresistive effect element 10C as modified example 1-3 has a stacked structure S10C instead of the stacked structure S10. Except for this point, the configuration of the magnetoresistive effect element 10C is substantially the same as the configuration of the magnetoresistive effect element 10 of the first embodiment. The stacked structure S10C has a first magnetization free layer 16 instead of the first magnetization free layer 11. The first magnetization free layer 16 has a so-called spin vortex structure. The first magnetization free layer 16 includes a magnetization M16 that swirls around a vortex core VC along a stacked plane perpendicular to the z direction.

[0043] 9 is a characteristics diagram showing the relationship between the magnetic flux density B (horizontal axis) of the external magnetic field applied to the magnetoresistive effect element 10C and the resistance value RC (vertical axis) of the magnetoresistive effect element 10C when a current is passed through the magnetoresistive effect element 10C in the z direction. Fig. 9 corresponds to Fig. 2 showing the characteristics of the magnetoresistive effect element 10 of the first embodiment.

[0044] FIG. 10 is a plan view schematically illustrating the behavior of the first magnetization free layer 16 of the magnetoresistive element 10C when an external magnetic field is applied, specifically, how the magnetization M16 changes depending on the magnitude of the magnetic flux density B of the external magnetic field applied to the magnetoresistive element 10C. (A) of FIG. 10 shows the direction of the magnetization M16 when the magnetic flux density B is -B2 in the characteristic diagram shown in FIG. 9. (B) of FIG. 10 shows the direction of the magnetization M16 when the magnetic flux density B is -B1 in the characteristic diagram shown in FIG. 9. (C) of FIG. 10 shows the direction of the magnetization M16 when the magnetic flux density B is 0 in the characteristic diagram shown in FIG. 9. (D) of FIG. 10 shows the direction of the magnetization M16 when the magnetic flux density B is B1 in the characteristic diagram shown in FIG. 9. (E) of FIG. 10 shows the direction of the magnetization M16 when the magnetic flux density B is B2 in the characteristic diagram shown in FIG. 9. The absolute value of B1 is equal to the absolute value of -B1, and the absolute value of B2 is equal to the absolute value of -B2. The lengths and directions of the white arrows in (A), (B), (D), and (E) of Figures 10 indicate the strength and direction of the external magnetic field applied to the magnetoresistive effect element 10C. That is, the longer the white arrow, the stronger the strength of the external magnetic field. (A) and (B) of Figures 10 indicate that the external magnetic field is applied to the magnetoresistive effect element 10C in the left direction of the paper, while (D) and (E) of Figures 10 indicate that the external magnetic field is applied to the magnetoresistive effect element 10C in the right direction of the paper.

[0045] As shown in FIG. 9, the magnetoresistive element 10C also behaves similarly to the magnetoresistive element 10 of the first embodiment in response to an applied external magnetic field. For example, the resistance value RC of the magnetoresistive element 10C reaches a maximum resistance value RCmax when the magnetic flux density B=0. FIGS. 8 and 10C schematically illustrate the state of the magnetoresistive element 10C when the magnetic flux density B=0. As shown in FIGS. 8 and 10C, when the magnetic flux density B of the external magnetic field is 0, a vortex core VC exists at the center of the stacked layer, and magnetization M16 swirls around it. Therefore, while the magnetization M16 of the same direction as the magnetization M12 of the second magnetization free layer 12 exists in the first magnetization free layer 16, magnetization M16 of a direction perpendicular to the magnetization M12 of the second magnetization free layer 12 and magnetization M16 of a direction antiparallel to the magnetization M12 also exist in the first magnetization free layer 16. Therefore, the resistance value RC of the magnetoresistive effect element 10C becomes relatively high. On the other hand, as shown in (A), (B), (D), and (E) of Figures 10A, 10B, 10C, when an external magnetic field is applied to the first magnetization free layer 16 having a spin vortex structure, the magnetic moment increases in the same direction as the external magnetic field. That is, most of the first magnetization free layer 16 has a magnetization M16 in the same direction as the external magnetic field. Since the direction of the magnetization M12 of the second magnetization free layer 12 also coincides with the direction of the external magnetic field, the resistance value of the magnetoresistive effect element 10C decreases as the strength of the external magnetic field applied increases when a current is flowing through the magnetoresistive effect element 10C in the z direction.

[0046] In this way, the resistance value also changes according to the strength (magnetic flux density) of the applied external magnetic field in the magnetoresistive effect element 10C as modification 1-3. Therefore, by knowing the correlation between the strength (magnetic flux density) of the external magnetic field and the resistance value in advance, the strength of the external magnetic field can be calculated by detecting the change in the resistance value of the magnetoresistive effect element 10C.

[0047] Furthermore, the magnetoresistive element 10C has a smaller variation in resistance value with respect to the z-direction component of the external magnetic field than the magnetoresistive element 10 of the first embodiment, and therefore has higher reliability.

[0048] (Fourth Modification) FIG. 11 is a cross-sectional view illustrating a cross-sectional configuration example of a magnetoresistive effect element 10D as a fourth modified example (hereinafter referred to as modified example 1-4) of the first embodiment of the present disclosure. FIG. 11 corresponds to FIG. 1A illustrating the magnetoresistive effect element 10 of the first embodiment. The magnetoresistive effect element 10D as modified example 1-4 includes a stacked structure S10D instead of the stacked structure S10. Except for this point, the configuration of the magnetoresistive effect element 10D is substantially the same as the configuration of the magnetoresistive effect element 10 of the first embodiment. In the stacked structure S10D, the magnetization M11 of the first magnetization free layer 11 and the magnetization M12 of the second magnetization free layer 12 are antiferromagnetically coupled. When the nonmagnetic layer 13 is a tunnel barrier layer, the magnetization M11 and the magnetization M12 are magnetostatically coupled and antiparallel to each other. Furthermore, when the nonmagnetic layer 13 is a nonmagnetic conductive layer, the magnetization M11 and the magnetization M12 are coupled by, for example, the RKKY interaction and are antiparallel to each other.

[0049] 12 is a characteristic diagram showing the relationship between the magnetic flux density B (horizontal axis) of the external magnetic field applied to the magnetoresistive effect element 10D and the resistance value RD (vertical axis) of the magnetoresistive effect element 10D when a current is passed through the magnetoresistive effect element 10D in the z direction. Fig. 12 corresponds to Fig. 2 showing the characteristic diagram of the magnetoresistive effect element 10 of the first embodiment.

[0050] 13A and 13B are plan views schematically illustrating the behavior of the first magnetization free layer 11 and the second magnetization free layer 12 of the magnetoresistive element 10D when an external magnetic field is applied, specifically, how the magnetizations M11 and M12 change depending on the magnitude of the magnetic flux density B of the external magnetic field applied to the magnetoresistive element 10D. (A) of FIG. 13 shows the orientations of the magnetizations M11 and M12 when the magnetic flux density B is −B2 in the characteristic diagram shown in FIG. 12. (B) of FIG. 13 shows the orientations of the magnetizations M11 and M12 when the magnetic flux density B is −B1 in the characteristic diagram shown in FIG. 12. (C) of FIG. 13 shows the orientations of the magnetizations M11 and M12 when the magnetic flux density B is 0 in the characteristic diagram shown in FIG. 12. (D) of FIG. 13 shows the orientations of the magnetizations M11 and M12 when the magnetic flux density B is B1 in the characteristic diagram shown in FIG. 12. (E) of FIG. 13 shows the directions of magnetizations M11 and M12 when magnetic flux density B=B2 in the characteristic diagram shown in FIG. 12. Note that the absolute value of B1 is equal to the absolute value of −B1, and the absolute value of B2 is equal to the absolute value of −B2. The lengths and directions of the white arrows in (A), (B), (D), and (E) of FIG. 13 indicate the strength and direction of the external magnetic field applied to the magnetoresistive element 10D. That is, the longer the white arrow, the stronger the strength of the external magnetic field. (A) and (B) of FIG. 13 show that the external magnetic field is applied to the magnetoresistive element 10D in the left direction on the paper, while (D) and (E) of FIG. 13 show that the external magnetic field is applied to the magnetoresistive element 10D in the right direction on the paper.

[0051] As shown in FIG. 12, the magnetoresistive element 10D also behaves in response to an applied external magnetic field in the same manner as the magnetoresistive element 10 of the first embodiment. For example, the resistance value RD of the magnetoresistive element 10D reaches a maximum resistance value RDmax when the magnetic flux density B=0. FIGS. 11 and 13C schematically show the state of the magnetoresistive element 10D when the magnetic flux density B=0. As shown in FIGS. 11 and 13C, when the magnetic flux density B of the external magnetic field is 0, the magnetizations M11 and M12 are antiparallel to each other. Therefore, the resistance value RD of the magnetoresistive element 10D becomes relatively high. On the other hand, as shown in FIGS. 13A, 13B, 13D, and 13E, when an external magnetic field is applied, the magnetizations M11 and M12 rotate to approach the direction of the external magnetic field. Here, the orientations of the magnetization M11 and the magnetization M12 approach parallelism as the strength of the external magnetic field, i.e., the absolute value of the magnetic flux density B, increases. Therefore, in the magnetoresistive element 10D, the resistance value decreases as the strength of the external magnetic field applied increases while a current is flowing through the magnetoresistive element 10D in the z direction.

[0052] In this way, the resistance value also changes according to the strength (magnetic flux density) of the applied external magnetic field in the magnetoresistive effect element 10D as modification 1-4. Therefore, by knowing in advance the correlation between the strength (magnetic flux density) of the external magnetic field and the resistance value, it is possible to calculate the strength of the external magnetic field by detecting the change in the resistance value of the magnetoresistive effect element 10D.

[0053] <2. Second Embodiment> [Configuration of magnetic field detection device 1] Next, the configuration of the magnetic field detection device 1 of the present disclosure will be described with reference to Fig. 14. Fig. 14 is a circuit diagram that schematically shows the circuit configuration of the magnetic field detection device 1 according to the second embodiment of the present disclosure. As shown in Fig. 14, the magnetic field detection device 1 includes a bridge circuit 7, a differential detector 8, and an arithmetic circuit 9. The magnetic field detection device 1 is able to detect changes in the intensity of the external magnetic field applied to the magnetic field detection device 1 by using changes in the output from the bridge circuit 7.

[0054] The bridge circuit 7 includes four resistors 21 to 24. The bridge circuit 7 includes a series-connected resistor 21 and resistor 22, and a series-connected resistor 23 and resistor 24, which are connected in parallel. More specifically, in the bridge circuit 7, a first end of the resistor 21 and a first end of the resistor 22 are connected at a connection point P1, a first end of the resistor 23 and a first end of the resistor 24 are connected at a connection point P2, a second end of the resistor 21 and a second end of the resistor 24 are connected at a connection point P3, and a second end of the resistor 22 and a second end of the resistor 23 are connected at a connection point P4. Here, the connection point P3 is set to a first potential, and the connection point P4 is set to a second potential. In the example shown in FIG. 14, the connection point P3 is connected to a power supply Vcc, and the connection point P4 is connected to a ground terminal GND. The connection point P1 and the connection point P2 are each connected to, for example, an input terminal of a differential detector 8.

[0055] In the bridge circuit 7, the magnetoresistive effect element 10 described in the first embodiment can be used as each of the resistors 21 and 23. That is, each of the resistors 21 and 23 can detect the intensity of the external magnetic field to be detected. The magnetoresistive effect elements 10A to 10D of the above-described Modifications 1-1 to 1-4 can also be used as each of the resistors 21 and 23. Meanwhile, in the bridge circuit 7, each of the resistors 22 and 24 is, for example, a fixed resistor. The resistors 22 and 24 are not limited to being fixed resistors. When each of the resistors 22 and 24 is a magnetoresistive effect element, the magnetization direction of the magnetization pinned layer in the magnetoresistive effect element serving as the resistor 22 and the magnetization direction of the magnetization pinned layer in the magnetoresistive effect element serving as the resistor 24 are preferably opposite to each other. This is because the direction (positive or negative sign) of the resistance variation of resistor 22 in response to the angle of the external magnetic field is opposite to the direction (positive or negative sign) of the resistance variation of resistor 24 in response to the angle of the external magnetic field, and by obtaining the differential potential between them, it is expected that these resistance variations will be offset, making it relatively easy to detect the strength of the external magnetic field.

[0056] [Operation of magnetic field detection device 1] In the magnetic field detection device 1, signals extracted from nodes P1 and P2 of the bridge circuit 7 flow into a differential detector 8. The differential detector 8 detects the potential difference between nodes P1 and P2 when a voltage is applied between nodes P3 and P4, i.e., the differential output dV, which is the difference between the voltage drop across resistor 21 and the voltage drop across resistor 24, and outputs the differential output dV as a differential signal SL to an arithmetic circuit 9. In the magnetic field detection device 1, if the resistance values ​​of resistor 22 and resistor 24 are configured to match the resistance values ​​of resistor 21 and resistor 23 in a zero magnetic field, the differential output dV becomes 0 (zero) in the initial state when no external magnetic field is applied. Furthermore, when an external magnetic field is applied to the bridge circuit 7, the resistance values ​​of the magnetoresistive effect elements 10 serving as resistors 21 and 23 each change in response to the strength of the applied external magnetic field. This results in a differential output dV that corresponds to the strength of the external magnetic field.

[0057] 15 is a characteristic diagram that schematically shows the relationship between magnetic flux density B (horizontal axis) representing the strength of the external magnetic field and differential output dV (vertical axis) in magnetic field detection device 1. As shown in FIG. 15, in magnetic field detection device 1, within a range of magnetic flux density B below a certain magnitude, there is a proportional relationship between magnetic flux density B and differential output dV. Arithmetic circuit 9 calculates the strength of the external magnetic field applied to bridge circuit 7 based on differential signal SL from differential detector 8, in accordance with the correlation shown in FIG. 15.

[0058] In this way, the magnetic field detection device 1 can determine the strength of the applied external magnetic field.

[0059] <3. Third Embodiment> [Configuration of magnetic field detection device 2] Next, the configuration of the magnetic field detection device 2 of the present disclosure will be described with reference to Fig. 16. Fig. 16 is a circuit diagram schematically illustrating the circuit configuration of the magnetic field detection device 2 according to the third embodiment of the present disclosure. As shown in Fig. 16, the magnetic field detection device 2 includes resistors 35 and 36, a bridge circuit 17, and analog-to-digital conversion circuits (ADCs) 18A and 18B. The magnetic field detection device 2 is capable of detecting changes in the intensity of the external magnetic field applied to the magnetic field detection device 2 by using changes in the outputs from the resistors 35 and 36 and the bridge circuit 17.

[0060] The bridge circuit 17 includes resistors 31 to 34. The bridge circuit 17 includes a series-connected resistor 31 and a resistor 32, and a series-connected resistor 33 and a resistor 34, which are connected in parallel to each other. More specifically, in the bridge circuit 17, a first end of the resistor 31 and a first end of the resistor 32 are connected at a connection point P1, a first end of the resistor 33 and a first end of the resistor 34 are connected at a connection point P2, a second end of the resistor 31 and a second end of the resistor 34 are connected at a connection point P3, and a second end of the resistor 32 and a second end of the resistor 33 are connected at a connection point P4. In the example shown in FIG. 16, the connection point P3 is connected to a power supply Vcc via the resistor 35, and the connection point P4 is connected to a ground terminal GND via the resistor 36. The connection point P1 is connected to the input terminal of an analog-digital conversion circuit (ADC) 18A, and the connection point P2 is connected to the input terminal of an analog-digital conversion circuit (ADC) 18B. Each of the resistors 31 to 34 of the bridge circuit 17 is, for example, a GMR element with a spin valve structure. That is, each of the resistors 31 to 34 includes a layered structure of a magnetization free layer whose magnetization direction changes depending on the direction of an external magnetic field, a non-magnetic layer, and a magnetization fixed layer whose magnetization is fixed in a specific direction regardless of an external magnetic field, and exhibits a resistance value that changes depending on the direction of the external magnetic field. Here, bridge circuit 17 is a specific example corresponding to a "bridge circuit" according to one aspect of the present disclosure, connection point P3 is a specific example corresponding to a "first terminal" according to one aspect of the present disclosure, and connection point P4 is a specific example corresponding to a "second terminal" according to one aspect of the present disclosure. Furthermore, the "first potential" according to one aspect of the present disclosure is a power supply potential set by a power supply Vcc, and the "second potential" according to one aspect of the present disclosure is a ground potential. Furthermore, for example, resistor 31 is a specific example corresponding to a "first magnetoresistance effect element" according to one aspect of the present disclosure, and resistor 32 is a specific example corresponding to a "second magnetoresistance effect element" according to one aspect of the present disclosure.

[0061] In the magnetic field detection device 2, the magnetoresistive effect element 10 described in the first embodiment can be used as each of the resistors 35 and 36. That is, each of the resistors 35 and 36 can detect the intensity of the external magnetic field to be detected. Note that the magnetoresistive effect elements 10A, 10C, and 10D of the above-described modified examples 1-1, 1-3, and 1-4 can also be used as each of the resistors 35 and 36.

[0062] In the magnetic field detection device 2, the bridge circuit 17 is a magnetic field angle information detector that detects the direction of the external magnetic field, and the resistors 35 and 36 are magnetic field strength information detectors that detect the strength of the external magnetic field. However, the signal components containing the magnetic field angle information and the signal components containing the magnetic field strength information are output as a pair of digital signals that are respectively converted by ADCs 18A and 18B from analog signals extracted from a pair of connection points P1 and P2.

[0063] FIG. 16 schematically illustrates the magnetization direction Fr of the magnetization free layer and the magnetization direction Pin of the magnetization fixed layer when each of the resistors 31 to 34 is a magnetoresistive effect element. In FIG. 16, the magnetization direction Fr is indicated by a dashed arrow, and the magnetization direction Pin is indicated by a solid arrow. Note that FIG. 16 illustrates a case where the X-axis direction and the Y-axis direction are parallel to a plane perpendicular to the z-axis, and an external magnetic field Hex is applied in a direction forming an angle Θ with respect to the +X direction. In the example of the bridge circuit 17 illustrated in FIG. 16, the magnetization direction Pin of the magnetization fixed layer of the resistor 31 is fixed in the +X direction, the magnetization direction Pin of the magnetization fixed layer of the resistor 32 is fixed in the −X direction, the magnetization direction Pin of the magnetization fixed layer of the resistor 33 is fixed in the −Y direction, and the magnetization direction Pin of the magnetization fixed layer of the resistor 34 is fixed in the +Y direction. In this case, if the output from ADC 18A is Vcos and the output from ADC 18B is Vsin, the strength Vamp of the external magnetic field Hex is calculated by the following formula (1), and the angle Θ of the external magnetic field Hex is calculated by the following formula (2). Note that in formulas (1) and (2), Vs0 represents the output Vsin when the angle Θ is 0°, and Vc0 represents the output Vcos when the angle Θ is 90°.

number

number

[0064] In this way, in the magnetic field detection device 2, the bridge circuit 17 as a magnetic field angle information detection unit that detects magnetic field angle information and the resistors 35, 36 as a magnetic field strength information detection unit that detects the strength of the external magnetic field are incorporated into a single circuit, thereby making it possible to simplify and compact the overall configuration.

[0065] <4. Fourth embodiment> [Configuration of magnetic field detection device 3] Next, the configuration of the magnetic field detection device 3 of the present disclosure will be described with reference to Fig. 17. Fig. 17 is a circuit diagram schematically illustrating the circuit configuration of the magnetic field detection device 3 according to the fourth embodiment of the present disclosure. As shown in Fig. 17, the magnetic field detection device 3 does not have resistors 35 and 36, and has a bridge circuit 19 instead of the bridge circuit 17. Except for this, the configuration of the magnetic field detection device 3 is substantially the same as the configuration of the magnetic field detection device 2. In the magnetic field detection device 3, by using a change in the output from the bridge circuit 19, it is possible to detect a change in the intensity of the external magnetic field applied to the magnetic field detection device 3.

[0066] The bridge circuit 19 includes resistors 41 to 44. The bridge circuit 19 includes a series-connected resistor 41 and a series-connected resistor 42, and a series-connected resistor 43 and a series-connected resistor 44, which are connected in parallel to each other. More specifically, in the bridge circuit 19, a first end of the resistor 41 and a first end of the resistor 42 are connected at a connection point P1, a first end of the resistor 43 and a first end of the resistor 44 are connected at a connection point P2, a second end of the resistor 41 and a second end of the resistor 44 are connected at a connection point P3, and a second end of the resistor 42 and a second end of the resistor 43 are connected at a connection point P4. In the example shown in FIG. 17, the connection point P3 is connected to a power supply Vcc, and the connection point P4 is connected to a ground terminal GND. The connection point P1 is connected to an input terminal of an analog-to-digital conversion circuit (ADC) 18A, and the connection point P2 is connected to an input terminal of an analog-to-digital conversion circuit (ADC) 18B. Each of the resistors 41 to 44 of the bridge circuit 19 is, for example, the magnetoresistive effect element 10B of the above-described modified example 1-2. Here, bridge circuit 19 is a specific example corresponding to a "bridge circuit" according to one aspect of the present disclosure, connection point P3 is a specific example corresponding to a "first terminal" according to one aspect of the present disclosure, and connection point P4 is a specific example corresponding to a "second terminal" according to one aspect of the present disclosure. Furthermore, the "first potential" according to one aspect of the present disclosure is a power supply potential set by a power supply Vcc, and the "second potential" according to one aspect of the present disclosure is a ground potential. Furthermore, for example, resistor 41 is a specific example corresponding to a "first magnetoresistance effect element" according to one aspect of the present disclosure, and resistor 42 is a specific example corresponding to a "second magnetoresistance effect element" according to one aspect of the present disclosure.

[0067] In the magnetic field detection device 3, the bridge circuit 19 serves as a magnetic field angle information detection unit that detects the direction of the external magnetic field and also as a magnetic field strength information detection unit that detects the strength of the external magnetic field. In the magnetic field detection device 3, similar to the magnetic field detection device 2 of the third embodiment, the strength Vamp of the external magnetic field Hex is calculated by equation (1), and the angle Θ of the external magnetic field Hex is calculated by equation (2).

[0068] In this way, the magnetic field detection device 3 is provided with a bridge circuit 19 that combines both a magnetic field angle information detection unit that detects magnetic field angle information and a magnetic field strength information detection unit that detects the strength of the external magnetic field, thereby making it possible to simplify and compact the overall configuration.

[0069] <5. Fifth Embodiment> Next, a magnetic sensor system 200 according to a fifth embodiment of the present disclosure will be described with reference to Fig. 18. Fig. 18 is a perspective view illustrating an example of the overall configuration of the magnetic sensor system 200 according to the present embodiment. The magnetic sensor system 200 is a specific example corresponding to a "magnetic sensor system" according to one aspect of the present disclosure.

[0070] The magnetic sensor system 200 includes a component 201 and a main body 202 that accommodates at least a portion of the component 201. The component 201 incorporates a magnetic field generator, such as a permanent magnet or electromagnet, that generates a magnetic field. The component 201 is configured to rotate in a direction D1 around a reference axis C serving as a first axis and move in a direction D2 parallel to the reference axis C. The component 201 may be a component such as a knob that is operated by a human operation. Examples of the magnetic sensor system 200 that includes such a component 201 include operating devices for air conditioners and car navigation systems in automobiles, operating devices for digital cameras and radios, and crowns for smart watches. Alternatively, the component 201 may be a component that operates in conjunction with an arbitrary driving device. The main body 202 incorporates a magnetic field detector. The magnetic field detectors 1 to 3 described in the second to fourth embodiments above can be used as the magnetic field detectors included in the main body 202.

[0071] In other words, the magnetic sensor system 200 is configured so that the direction of the magnetic field applied to the magnetic field detection device changes when the magnetic field detection device and the magnetic field generator rotate relative to each other around the reference axis C as the center of rotation, and the strength of the magnetic field applied to the magnetic field detection device changes when the relative position of the magnetic field detection device and the magnetic field generator along the reference axis C changes.

[0072] In this way, the magnetic sensor system 200 has a simple configuration and is capable of detecting both the angle and the strength of the magnetic field applied to the magnetic field detection device.

[0073] The above-described embodiments and modifications are provided to facilitate understanding of the present disclosure and are not intended to limit the present disclosure. Therefore, the elements disclosed in the above embodiments are intended to include all design modifications and equivalents that fall within the technical scope of the present technology. In other words, the present disclosure is not limited to the above-described embodiments, and various modifications are possible. [Explanation of symbols]

[0074] 1 to 3...magnetic field detection device, 6, 7...bridge circuit, 8...differential detection device, 9...arithmetic circuit, 10, 10A to 10D...magnetoresistive effect element, 11...first magnetization free layer, 12...second magnetization free layer, 13, 15...non-magnetic layer, 14...magnetization fixed layer, 200...magnetic sensor system.

Claims

1. a laminated structure in which a first magnetization free layer, a first non-magnetic layer, and a second magnetization free layer are laminated in this order in a lamination direction; The outer edge shape of the laminated structure along a plane perpendicular to the lamination direction is an isotropic shape. Magnetoresistive element.

2. the first magnetization free layer has an easy axis of magnetization aligned with the stacking direction, The second magnetization free layer has a hard axis of magnetization aligned along the stacking direction.

2. The magnetoresistive element according to claim 1.

3. Each of the first and second magnetization free layers has an easy axis of magnetization aligned along the stacking direction.

2. The magnetoresistive element according to claim 1.

4. The laminated structure further includes a second non-magnetic layer and a magnetization fixed layer laminated in this order on the side opposite to the first non-magnetic layer as viewed from the second magnetization free layer.

2. The magnetoresistive element according to claim 1.

5. the first magnetization free layer has a spin vortex structure including a magnetization swirling along the plane; The second magnetization free layer has a hard axis of magnetization aligned along the stacking direction.

2. The magnetoresistive element according to claim 1.

6. The first magnetization free layer and the second magnetization free layer are antiferromagnetically coupled.

2. The magnetoresistive element according to claim 1.

7. When no external magnetic field is applied, the angle between the magnetization direction of the first magnetization free layer and the magnetization direction of the second magnetization free layer is greater than 90° and equal to or less than 180°.

7. The magnetoresistive element according to claim 6.

8. The outer edge of the laminated structure has a circular shape.

2. The magnetoresistive element according to claim 1.

9. The anisotropy magnetic field strength of the first magnetization free layer is different from the anisotropy magnetic field strength of the second magnetization free layer.

2. The magnetoresistive element according to claim 1.

10. one or more magnetoresistive effect elements; Each of the one or more magnetoresistive effect elements a laminated structure in which a first magnetization free layer, a first non-magnetic layer, and a second magnetization free layer are laminated in this order in a lamination direction; The outer edge shape of the laminated structure along a plane perpendicular to the lamination direction is an isotropic shape. Magnetic field detection device.

11. An angle sensor connected in series to the magnetoresistive element is further provided. The magnetic field detection device according to claim 10.

12. a first terminal set to a first potential; a second terminal set to a second potential different from the first potential; a bridge circuit provided between the first terminal and the second terminal; Furthermore, the one or more magnetoresistive effect elements include a first magnetoresistive effect element and a second magnetoresistive effect element; The first magnetoresistive element and the second magnetoresistive element form the bridge circuit. The magnetic field detection device according to claim 10.

13. The bridge circuit includes a first fixed resistor and a second fixed resistor in addition to the first magnetoresistive element and the second magnetoresistive element. The magnetic field detection device according to claim 12.

14. the bridge circuit is configured to include a third magnetoresistive element and a fourth magnetoresistive element in addition to the first magnetoresistive element and the second magnetoresistive element, each of the third magnetoresistive element and the fourth magnetoresistive element has a magnetization fixed layer; The magnetization direction of the magnetization fixed layer of the third magnetoresistive element is opposite to the magnetization direction of the magnetization fixed layer of the fourth magnetoresistive element. The magnetic field detection device according to claim 12.

15. a first terminal set to a first potential; a second terminal set to a second potential different from the first potential; a bridge circuit provided between the first terminal and the second terminal; Furthermore, The one or more magnetoresistive effect elements are disposed between the first terminal and the bridge circuit, or between the second terminal and the bridge circuit, or disposed between the first terminal and the bridge circuit and between the second terminal and the bridge circuit The magnetic field detection device according to claim 10.

16. The bridge circuit detects both the strength of an external magnetic field applied to the bridge circuit and the angle of the external magnetic field.

16. The magnetic field detection device according to claim 15.

17. The outer edge of the laminated structure has a circular shape. The magnetic field detection device according to claim 10.

18. a bridge circuit including first to fourth magnetoresistive effect elements; each of the first to fourth magnetoresistive elements has a stacked structure in which a magnetization fixed layer, a second non-magnetic layer, a second magnetization free layer, a first non-magnetic layer, and a first magnetization free layer are stacked in this order in a stacking direction; the first magnetization free layer has an easy axis of magnetization aligned with the stacking direction, The second magnetization free layer has a hard axis of magnetization aligned along the stacking direction. Magnetic field detection device.

19. The outer edge shape of the laminated structure along a plane perpendicular to the lamination direction is an isotropic shape.

19. The magnetic field detection device according to claim 18.

20. The bridge circuit detects both the strength of an external magnetic field applied to the bridge circuit and the angle of the external magnetic field.

20. The magnetic field detection device according to claim 18 or 19.

21. A magnetic field detection device and a magnetic field generator that generates a magnetic field are provided, The magnetic field detection device and the magnetic field generator are configured to rotate relative to each other around a first axis, thereby changing the direction of the magnetic field applied to the magnetic field detection device, and the strength of the magnetic field applied to the magnetic field detection device is configured to change as the relative position of the magnetic field detection device and the magnetic field generator along the first axis changes, The magnetic field detection device is one or more magnetoresistive effect elements; Each of the one or more magnetoresistive effect elements a laminated structure in which a first magnetization free layer, a first non-magnetic layer, and a second magnetization free layer are laminated in this order in a lamination direction; The shape of the laminated structure along a plane perpendicular to the lamination direction is an isotropic shape. Magnetic sensor system.

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