Magnetic sensor

Abstract

This suppresses variations in properties caused by the direction of magnetization in the free layer. [Solution] The magnetic sensor 1 comprises a plurality of first MR elements 50A and a plurality of second MR elements 50B. Each of the plurality of first MR elements 50A and the plurality of second MR elements 50B has a resistance change characteristic in which the resistance value changes when the strength of the applied magnetic field is the same, depending on the stable state of the magnetic vortex structure. The statistical distribution of the resistance change amount ΔR of the plurality of first MR elements 50A is a first distribution 81 centered on a first value ΔR1. The statistical distribution of the resistance change amount ΔR of the plurality of second MR elements 50B is a second distribution 82 centered on a second value ΔR2. The group including the plurality of first MR elements 50A and the plurality of second MR elements 50B has the characteristic that the statistical distribution of the resistance change amount ΔR is a third distribution centered on a third value between the first value ΔR1 and the second value ΔR2.

Description

Technical Field

[0001] The present disclosure relates to a magnetic sensor including a plurality of magnetoresistive elements each including a free layer configured to be able to have a magnetic vortex structure, respectively.

Background Art

[0002] In recent years, magnetic sensors have been used in various applications. As a magnetic sensor, a spin valve type magnetoresistive element provided on a substrate is known. The spin valve type magnetoresistive element has a magnetization fixed layer having a magnetization with a fixed direction, a free layer having a magnetization whose direction can change according to the direction of an applied magnetic field, and a gap layer disposed between the magnetization fixed layer and the free layer.

[0003] Patent Document 1 discloses a magnetic sensor device having a plurality of TMR (tunnel magnetoresistance) elements. The TMR element has a free layer having a disk-shaped structure. In the free layer, a magnetization pattern having a closed magnetic flux, also called a vortex state, is spontaneously formed. In a magnetoresistive element including a free layer having a magnetic vortex structure as described in Patent Document 1, the center of the magnetic vortex structure moves according to the magnetic field to be detected, and thereby the resistance value of the magnetoresistive element changes.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a free layer with a magnetic vortex structure, the direction of magnetization in the stable state can be either clockwise or counterclockwise. Ideally, the resistance value of a magnetoresistive element changes in the same way in both cases. However, in reality, the resistance value of a magnetoresistive element can differ due to its structure and other factors.

[0006] Furthermore, magnetic sensors may be temporarily subjected to an external magnetic field that is not the magnetic field being detected, but which can cause magnetic saturation of the free layer. In free layers with a magnetic vortex structure, the direction of magnetization in the stable state may reverse after such an external magnetic field is applied. As a result, the characteristics of the magnetic sensor may fluctuate before and after the application of the external magnetic field.

[0007] This disclosure has been made in view of the aforementioned problems, and its purpose is to provide a magnetic sensor that can suppress variations in properties caused by the direction of magnetization of a free layer configured to have a magnetic vortex structure. [Means for solving the problem]

[0008] A magnetic sensor according to a first aspect of this disclosure comprises a plurality of first magnetoresistive elements and a plurality of second magnetoresistive elements, and is configured to detect a magnetic field to be detected and generate a detection signal. The plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements are electrically connected. Each of the plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements includes a magnetization-fixed layer having magnetization with a fixed direction, and a free layer that can have a magnetic vortex structure and is configured so that the center of the magnetic vortex structure moves in response to the applied magnetic field, and has a resistance change characteristic in which the resistance value changes when the strength of the applied magnetic field is the same, depending on the stable state of the magnetic vortex structure. A first group, which is a plurality of first magnetoresistive elements, has the characteristic that the statistical distribution of the resistance change amount, which is a parameter corresponding to the resistance change characteristic, is a first distribution centered on a first value. A second group, which is a plurality of second magnetoresistive elements, has the characteristic that the statistical distribution of the resistance change amount is a second distribution centered on a second value different from the first value. A third group, which includes multiple first magnetoresistive elements and multiple second magnetoresistive elements, has the characteristic that the statistical distribution of the resistance change is a third distribution centered on a third value between the first and second values.

[0009] A magnetic sensor according to a second aspect of this disclosure comprises a plurality of magnetoresistive elements and is configured to detect a target magnetic field and generate a detection signal. Each of the plurality of magnetoresistive elements includes a magnetization-fixed layer having magnetization with a fixed direction and a free layer that can have a magnetic vortex structure and is configured so that the center of the magnetic vortex structure moves in response to the applied magnetic field, and has a resistance change characteristic in which the resistance value changes when the strength of the applied magnetic field is the same, depending on the stable state of the magnetic vortex structure. The group of plurality of magnetoresistive elements has the characteristic that the statistical distribution of the resistance change amount, which is a parameter corresponding to the resistance change characteristic, is distributed around a predetermined value. Each of the plurality of magnetoresistive elements is configured so that the free layer does not become magnetically saturated when the strength of the target magnetic field is within a first range. The detection signal changes within a second range when the strength of the target magnetic field changes within a first range. The group has the characteristic that as the number of plurality of magnetoresistive elements increases, the statistical distribution of the resistance change amount of the resistive section configured by electrically connecting the plurality of magnetoresistive elements approaches a normal distribution and the standard deviation of the distribution decreases. The number of magnetoresistive elements is the number such that the fluctuation in the detection signal before and after an external magnetic field that magnetically saturates the free layer is temporarily applied to the multiple magnetoresistive elements is 5% or less of the difference between the maximum and minimum values ​​in the second range, when the strength of the magnetic field to be detected is at a specific strength within the first range. [Effects of the Invention]

[0010] In the magnetic sensors of the first and second embodiments of this disclosure, the statistical distribution of the resistance change amount, which is a parameter corresponding to the resistance change characteristics, has predetermined characteristics. As a result, according to this disclosure, it is possible to suppress variations in characteristics caused by the direction of magnetization of the free layer. [Brief explanation of the drawing]

[0011] [Figure 1] This is a plan view showing a magnetic sensor according to the first embodiment of the present disclosure. [Figure 2]This is a circuit diagram showing the circuit configuration of a magnetic sensor according to the first embodiment of this disclosure. [Figure 3] This is a plan view showing a part of the resistor in the first embodiment of the present disclosure. [Figure 4] This is a plan view showing a portion of the element array in the first embodiment of the present disclosure. [Figure 5] This is a perspective view showing a magnetoresistive element in the first embodiment of the present disclosure. [Figure 6] This is a plan view showing the free layer of a magnetoresistive element in the first embodiment of the present disclosure. [Figure 7] This is a plan view showing the free layer of a magnetoresistive element in the first embodiment of this disclosure when a target magnetic field is applied to it. [Figure 8] This is a plan view showing the free layer of a magnetoresistive element in the first embodiment of this disclosure when a target magnetic field is applied to it. [Figure 9] This is an explanatory diagram showing the relationship between the intensity of the magnetic field component and the magnitude of the magnetization of the entire free layer in the first embodiment of this disclosure. [Figure 10] This is a schematic plan view showing the magnetization of a local portion of the magnetized fixed layer and the magnetization of the free layer of a magnetoresistive element in the first embodiment of the present disclosure. [Figure 11] This is an explanatory diagram showing the relationship between the intensity of the magnetic field component and the resistance value of the magnetoresistive element in the first embodiment of this disclosure. [Figure 12] This is an explanatory diagram showing the statistical distribution of the resistance change amounts for each of the first to third groups in the first embodiment of the present disclosure. [Figure 13] This is an explanatory diagram showing the statistical distribution of the resistance change amount of the resistor in the first embodiment of this disclosure. [Figure 14] This is a plan view showing an example of the arrangement of magnetoresistive elements in the first embodiment of the present disclosure. [Figure 15] This is a plan view showing a free layer to which a structure has been added in the first embodiment of the present disclosure. [Figure 16]It is a plan view showing a free layer having a planar shape with a controllable magnetization direction in the first embodiment of the present disclosure. [Figure 17] It is a plan view showing a first structure for controlling the magnetization directions of the MR element and the free layer in the first embodiment of the present disclosure. [Figure 18] It is a plan view showing a second structure for controlling the magnetization directions of the MR element and the free layer in the first embodiment of the present disclosure. [Figure 19] It is an explanatory view schematically showing the direction of current flowing through the magnetoresistive effect element in the first embodiment of the present disclosure. [Figure 20] It is an explanatory view schematically showing the magnetic field generated due to the current flowing through the magnetoresistive effect element in the first embodiment of the present disclosure. [Figure 21] It is a plan view showing a first modification of the magnetic sensor according to the first embodiment of the present disclosure. [Figure 22] It is a plan view showing a second modification of the magnetic sensor according to the first embodiment of the present disclosure. [Figure 23] It is a plan view showing a third modification of the magnetic sensor according to the first embodiment of the present disclosure. [Figure 24] It is a side view showing the magnetoresistive effect element and the shield in the second embodiment of the present disclosure. [Figure 25] It is an explanatory view showing the relationship between the intensity of the magnetic field component and the detection signal in the second embodiment of the present disclosure.

Embodiments for Carrying Out the Invention

[0012] [First Embodiment] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. First, referring to FIGS. 1 and 2, a schematic configuration of a magnetic sensor according to the first embodiment of the present disclosure will be described. FIG. 1 is a plan view showing a magnetic sensor 1 according to the present embodiment. FIG. 2 is a circuit diagram showing the circuit configuration of the magnetic sensor 1 according to the present embodiment.

[0013] The magnetic sensor 1 in this embodiment includes a plurality of magnetoresistive elements (hereinafter referred to as MR elements) 50. Each of the MR elements 50 is configured such that its resistance value changes according to the target magnetic field, which is the magnetic field detected by the magnetic sensor 1. The MR elements 50 are shown in Figure 3 and other figures, which will be described later.

[0014] The magnetic sensor 1 further includes a power terminal 11, a ground terminal 12, a first output terminal 13, a second output terminal 14, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. The power terminal 11, the ground terminal 12, the first output terminal 13, and the second output terminal 14 are each composed of electrode layers made of a conductive material. Each of the first to fourth resistors R1 to R4 contains multiple MR elements 50 from a plurality of MR elements 50.

[0015] As shown in Figure 2, the first resistor R1 is located between the power supply terminal 11 and the first output terminal 13 in the circuit configuration. The second resistor R2 is located between the ground terminal 12 and the first output terminal 13 in the circuit configuration. The third resistor R3 is located between the ground terminal 12 and the second output terminal 14 in the circuit configuration. The fourth resistor R4 is located between the power supply terminal 11 and the second output terminal 14 in the circuit configuration. In this application, the expression "in the circuit configuration" refers to the arrangement on the circuit diagram, not the arrangement in the physical configuration.

[0016] A predetermined voltage or current is applied to the power terminal 11. The ground terminal 12 is connected to ground.

[0017] As shown in Figure 1, the magnetic sensor 1 further includes a substrate 10. The power terminal 11, ground terminal 12, first output terminal 13, and second output terminal 14 are provided on the substrate 10.

[0018] Here, as shown in Figure 1, we define the X, Y, and Z directions. The X, Y, and Z directions are orthogonal to each other. Furthermore, the direction opposite to the X direction is defined as the -X direction, the direction opposite to the Y direction is defined as the -Y direction, and the direction opposite to the Z direction is defined as the -Z direction. In this embodiment, in particular, the direction perpendicular to the surface of the substrate 10 is defined as the Z direction.

[0019] Furthermore, below, a position located at the end of the Z-direction relative to a certain reference position will be referred to as "above," and a position opposite to "above" relative to a certain reference position will be referred to as "below." Also, with respect to the components of magnetic sensor 1, the surface located at the end in the Z-direction will be referred to as the "top surface," and the surface located at the end in the -Z-direction will be referred to as the "bottom surface." In addition, the expression "when viewed from a predetermined direction (for example, the Z-direction)" means viewing the object from a position at a distance in a predetermined direction or a direction parallel to the predetermined direction.

[0020] The substrate 10 includes element placement regions A1, A2, A3, and A4. In this embodiment, element placement regions A1 to A4 are defined as planar regions parallel to the XY plane. Each of the multiple MR elements 50 is positioned so as to overlap with one of the element placement regions A1 to A4 when viewed from the Z direction. For convenience, in this embodiment, element placement regions A1 to A4 are assumed to be located on the upper surface of the substrate 10.

[0021] Multiple MR elements 50 are arranged in element placement regions A1 to A4. Multiple MR elements 50 constituting the first resistance section R1 are arranged in element placement region A1. Multiple MR elements 50 constituting the second resistance section R2 are arranged in element placement region A2. Multiple MR elements 50 constituting the third resistance section R3 are arranged in element placement region A3. Multiple MR elements 50 constituting the fourth resistance section R4 are arranged in element placement region A4.

[0022] In the example shown in Figure 1, element placement region A2 is located ahead of element placement region A1 in the X direction. Element placement region A3 is located ahead of element placement region A2 in the -Y direction. Element placement region A4 is located ahead of element placement region A3 in the -X direction, and also ahead of element placement region A1 in the -Y direction.

[0023] Note that the arrangement of the power terminal 11, ground terminal 12, first output terminal 13, second output terminal 14, and element placement regions A1 to A4 (first to fourth resistors R1 to R4) is not limited to the example shown in Figure 1. For example, element placement regions A1 to A4 may be arranged in any order along a direction parallel to the X direction or parallel to the Y direction.

[0024] Next, the specific structures of the first to fourth resistors R1 to R4 will be described in detail with reference to Figures 3 and 4. Here, the first resistor R1 will be used as an example. Figure 3 is a plan view showing a part of the first resistor R1. Figure 4 is a plan view showing a part of the element array. In Figures 3 and 4, multiple circles represent multiple MR elements 50.

[0025] The first resistor R1 includes multiple element arrays 55. Each of the element arrays 55 includes a wire 40 and multiple MR elements 50 connected in series by the wire 40. The element arrays 55 may be connected in series or in parallel with each other by two terminals (not shown).

[0026] The wiring 40 includes a plurality of lower electrodes 41 and a plurality of upper electrodes 42. Each lower electrode 41 has an elongated shape. A gap is formed between two adjacent lower electrodes 41 that are spaced apart. On the upper surface of each lower electrode 41, MR elements 50 are arranged near both ends in the longitudinal direction of the lower electrode 41. Each upper electrode 42 has an elongated shape and, when viewed from the Z direction, is arranged on two adjacent lower electrodes 41 that are spaced apart and overlaps with two adjacent MR elements 50.

[0027] In the examples shown in Figures 3 and 4, at least a portion of each of the multiple element rows 55 extends in a direction parallel to the X direction. Therefore, in at least a portion of each of the multiple element rows 55, the multiple MR elements 50 are arranged in a direction parallel to the X direction. Also, in at least a portion of each of the multiple element rows 55, each of the multiple lower electrodes 41 and the multiple upper electrodes 42 has a shape that is elongated in a direction parallel to the X direction.

[0028] Note that the shape of each of the multiple element rows 55 is not limited to the examples shown in Figures 3 and 4. For example, each of the multiple element rows 55 may extend in any direction other than the direction parallel to the X direction. Alternatively, each of the multiple element rows 55 may include multiple parts that extend in different directions from each other.

[0029] Up to this point, we have explained using the first resistor R1 as an example. The explanation above for the first resistor R1 also applies to the second through fourth resistors R2 to R4.

[0030] Next, the configuration of the MR element 50 will be described with reference to Figures 5 and 6. Figure 5 is a perspective view showing the MR element 50. Figure 6 is a plan view showing the free layer of the MR element 50.

[0031] The MR element 50 includes a magnetization-fixed layer 51 having a magnetization 51m with a fixed direction, a free layer 53, and a gap layer 52 disposed between the magnetization-fixed layer 51 and the free layer 53. The material and shape of the free layer 53 are selected so that it may have a magnetic vortex structure (also called a vortex structure). The gap layer 52 is a tunnel barrier layer or a non-magnetic conductive layer.

[0032] The free layer 53 has a cylindrical or nearly cylindrical shape. The free layer 53 also has a magnetization 53m that is swirled around the center 53c of the magnetic vortex structure. When no magnetic field is applied to the MR element 50, the center 53c of the magnetic vortex structure coincides with or nearly coincides with the axis of the cylinder. The free layer 53 is configured so that the center 53c of the magnetic vortex structure can move in response to the target magnetic field MF. In the examples shown in Figures 5 and 6, the entire MR element 50 has a cylindrical shape.

[0033] The center 53c of the magnetic vortex structure moves when a component of the target magnetic field MF perpendicular to the Z direction is applied to the free layer 53. Within the range of change in the intensity of this component, it is preferable that the free layer 53 does not become magnetically saturated.

[0034] In this embodiment, the magnetization 51m of the magnetized fixed layer 51 includes a component in a direction parallel to the X direction. If the magnetization 51m of the magnetized fixed layer 51 includes a component in a specific direction, that component may be the main component of the magnetization 51m of the magnetized fixed layer 51. In this embodiment, if the magnetization 51m of the magnetized fixed layer 51 includes a component in a specific direction, the direction of the magnetization 51m of the magnetized fixed layer 51 will be a specific direction or approximately a specific direction.

[0035] The MR element 50 may further include an antiferromagnetic layer. The antiferromagnetic layer is made of an antiferromagnetic material and creates exchange coupling with the magnetization fixed layer 51 to fix the direction of the magnetization 51m of the magnetization fixed layer 51. Alternatively, the magnetization fixed layer 51 may be a so-called self-pinned fixed layer (Synthetic Ferri Pinned layer, SFP layer). The self-pinned fixed layer has a laminated ferri structure in which a ferromagnetic layer, a non-magnetic intermediate layer, and a ferromagnetic layer are stacked, and the two ferromagnetic layers are antiferromagnetically coupled.

[0036] Here, we will explain the resistance value of the MR element 50, taking the case where the direction of the magnetization 51m of the magnetized fixed layer 51 is the -X direction as an example. Figures 7 and 8 show the free layer 53 when a magnetic field component MFx parallel to the X direction of the target magnetic field MF is applied to the free layer 53.

[0037] Figure 7 shows the free layer 53 when the direction of the magnetic field component MFx is in the X direction. In this case, the center 53c of the magnetic vortex structure moves due to the magnetic field component MFx, and the amount of magnetization 53m oriented in the X direction becomes greater than the amount of magnetization 53m oriented in the -X direction. In this case, the resistance value of the MR element 50 increases.

[0038] Figure 8 shows the free layer 53 when the direction of the magnetic field component MFx is in the -X direction. In this case, the center 53c of the magnetic vortex structure moves due to the magnetic field component MFx, and the amount of magnetization 53m oriented in the -X direction becomes greater than the amount of magnetization 53m oriented in the X direction. In this case, the resistance value of the MR element 50 decreases.

[0039] The change in the resistance of the MR element 50 depends on the strength of the magnetic field component MFx. When the direction of the magnetic field component MFx is in the X direction, as the strength of the magnetic field component MFx increases, the amount of magnetization 53m oriented in the X direction increases. The resistance of the MR element 50 increases as the amount of magnetization 53m oriented in the X direction increases. Also, when the direction of the magnetic field component MFx is in the -X direction, as the strength of the magnetic field component MFx increases, the amount of magnetization 53m oriented in the -X direction increases. The resistance of the MR element 50 decreases as the amount of magnetization 53m oriented in the -X direction increases. When the strength of the magnetic field component MFx increases, the resistance of the MR element 50 changes in a direction in which its increase or decrease increases, respectively. When the strength of the magnetic field component MFx decreases, the resistance of the MR element 50 changes in a direction in which its increase or decrease decreases, respectively. In this embodiment in particular, the relationship between the strength of the magnetic field component MFx and the resistance of the MR element 50 is linear or nearly linear, as long as the requirement that the free layer 53 does not saturate is met.

[0040] Next, with reference to Figure 9, the relationship between the intensity of the magnetic field component MFx and the magnitude of the magnetization of the free layer 53 will be explained. Figure 9 is a characteristic diagram that schematically shows the relationship between the intensity of the magnetic field component MFx and the magnitude of the magnetization of the free layer 53. In Figure 9, the horizontal axis represents the intensity Hx of the magnetic field component MFx, and the vertical axis represents the magnitude Mx of the magnetization of the free layer 53. In Figure 9, the intensity Hx when the direction of the magnetic field component MFx is in the X direction is represented by a positive value, and the intensity Hx when the direction of the magnetic field component MFx is in the -X direction is represented by a negative value. When the direction of the magnetic field component MFx is in the X direction, as the amount of magnetization 53m directed in the X direction increases, the magnitude Mx of the magnetization of the free layer 53 increases. When the direction of the magnetic field component MFx is in the -X direction, as the amount of magnetization 53m directed in the -X direction increases, the magnitude Mx of the magnetization of the free layer 53 decreases.

[0041] First, let's explain the case where the intensity Hx is increased from 0. When the intensity Hx is gradually increased from 0, the magnitude of the magnetization Mx also gradually increases. When the intensity Hx reaches a value of Hx1 or greater, the magnitude of the magnetization Mx becomes constant, and the free layer 53 becomes magnetically saturated.

[0042] Next, we will explain the case where the intensity Hx is decreased from 0. When the intensity Hx is gradually decreased from 0, the magnitude of the magnetization Mx also gradually decreases. When the intensity Hx becomes less than or equal to Hx2, the magnitude of the magnetization Mx becomes constant, and the free layer 53 becomes magnetically saturated.

[0043] As shown in Figure 9, within a predetermined range where the intensity Hx is greater than value Hx2 and less than value Hx1, the magnetization magnitude Mx changes linearly with respect to the change in intensity Hx. "Linearly changing" means that, in the characteristic diagram showing the relationship between intensity Hx and magnetization magnitude Mx, the magnetization magnitude Mx changes linearly or nearly linearly with respect to the change in intensity Hx.

[0044] In this embodiment, it is preferable that the free layer 53 does not become magnetically saturated within the range of change in intensity Hx, and it is more preferable that the magnitude of magnetization Mx changes linearly with respect to the change in intensity Hx.

[0045] Furthermore, if the intensity Hx becomes greater than the value Hx1 and the free layer 53 becomes magnetically saturated, and then the intensity Hx is decreased from a value Hx3 greater than Hx1, the magnitude of magnetization Mx hardly changes until it reaches a value Hx4 less than Hx1. When the intensity Hx becomes less than the value Hx4, the magnitude of magnetization Mx changes linearly with respect to the change in intensity Hx, similar to when the intensity Hx is changed within a predetermined range greater than Hx2 and less than Hx1.

[0046] Similarly, if the intensity Hx is increased from a value Hx5 (which is less than Hx2) after the free layer 53 has become magnetically saturated when the intensity Hx is less than Hx2, the magnitude of magnetization Mx hardly changes until it reaches a value Hx6 (which is greater than Hx2). Once the intensity Hx is greater than Hx6, the magnitude of magnetization Mx changes linearly with respect to the change in intensity Hx, similar to when the intensity Hx is varied within a predetermined range greater than Hx2 and less than Hx1.

[0047] Although not shown in the diagram, the relationship between intensity Hx and the resistance of the MR element 50 is similar to the relationship between intensity Hx and the magnitude of the magnetization of the entire free layer 53.

[0048] Next, referring to Figure 2, the direction of magnetization 51m of the magnetization fixed layer 51 in each of the first to fourth resistance sections R1 to R4 will be explained. In the first resistance section R1, the magnetization 51m of each magnetization fixed layer 51 of the multiple MR elements 50 includes a component in the first magnetization direction. In the second resistance section R2, the magnetization 51m of each magnetization fixed layer 51 of the multiple MR elements 50 includes a component in the second magnetization direction, opposite to the first magnetization direction. In the third resistance section R3, the magnetization 51m of each magnetization fixed layer 51 of the multiple MR elements 50 includes a component in the first magnetization direction. In the fourth resistance section R4, the magnetization 51m of each magnetization fixed layer 51 of the multiple MR elements 50 includes a component in the second magnetization direction. In Figure 2, the two arrows drawn in the first and third resistance sections R1 and R3, respectively, indicate the first magnetization direction. In Figure 2, the two arrows drawn on the second and fourth resistors R2 and R4, respectively, indicate the second magnetization direction. In this embodiment, the first magnetization direction is in the X direction, and the second magnetization direction is in the -X direction.

[0049] Next, with reference to Figure 2, at least one detection signal generated by the magnetic sensor 1 will be described. When the direction of the magnetic field component MFx is the X direction, the resistance values ​​of each of the multiple MR elements 50 in the first and third resistive sections R1 and R3 decrease, and the resistance values ​​of each of the multiple MR elements 50 in the second and fourth resistive sections R2 and R4 increase, compared to the state in which the magnetic field component MFx is absent. As a result, the resistance values ​​of each of the first and third resistive sections R1 and R3 decrease, and the resistance values ​​of each of the second and fourth resistive sections R2 and R4 increase.

[0050] When the direction of the magnetic field component MFx is in the -X direction, the changes in the resistance values ​​of the first to fourth resistance sections R1 to R4 are reversed compared to the case where the direction of the magnetic field component MFx is in the X direction.

[0051] Thus, when the direction and intensity of the magnetic field component MFx change, the resistance values ​​of the first to fourth resistors R1 to R4 change such that the resistance values ​​of the first and third resistors R1 and R3 increase while the resistance values ​​of the second and fourth resistors R2 and R4 decrease, or the resistance values ​​of the first and third resistors R1 and R3 decrease while the resistance values ​​of the second and fourth resistors R2 and R4 increase. As a result, the potential at the connection point of the first and second resistors R1 and R2, i.e., the potential of the first output terminal 13, and the potential at the connection point of the third and fourth resistors R3 and R4, i.e., the potential of the second output terminal 14, change. The magnetic sensor 1 may generate a signal corresponding to the potential of the first output terminal 13 and a signal corresponding to the potential of the second output terminal 14 as detection signals. Alternatively, the magnetic sensor 1 may generate a signal corresponding to the potential difference between the first output terminal 13 and the second output terminal 14 as a detection signal. In this case, the magnetic sensor 1 may further include a differential amplifier (difference detector) that outputs a signal corresponding to the potential difference between the first output terminal 13 and the second output terminal 14 as a detection signal.

[0052] Next, a brief description will be given of the manufacturing method of the magnetic sensor 1 according to this embodiment. The manufacturing method of the magnetic sensor 1 includes the step of forming a plurality of MR elements 50 on a substrate 10. In the step of forming a plurality of MR elements 50, first, a plurality of initial MR elements that will later become the plurality of MR elements 50 are formed. Each of the plurality of initial MR elements includes at least an initial magnetization fixed layer that will later become a magnetization fixed layer 51, a free layer 53, and a gap layer 52.

[0053] Next, the magnetization direction of the initial magnetization fixed layer is fixed in the predetermined direction using laser light and an external magnetic field in a predetermined direction. For example, in the case of multiple initial MR elements that will later become the multiple MR elements 50 of the first and third resistance sections R1 and R3, laser light is irradiated onto the multiple initial MR elements while applying an external magnetic field in the first magnetization direction (X direction). If the initial MR elements include an antiferromagnetic layer, the laser light is irradiated such that the temperature of the multiple initial MR elements irradiated with the laser light is above the blocking temperature of the antiferromagnetic layer. The temperature of the multiple initial MR elements can be adjusted, for example, by the intensity or pulse width of the laser light. After irradiation with laser light, when the temperature of the multiple initial MR elements falls below the blocking temperature, the magnetization direction of the initial magnetization fixed layer is fixed in the first magnetization direction. As a result, the initial magnetization fixed layer becomes the magnetization fixed layer 51, and the multiple initial MR elements become the multiple MR elements 50 of the first and third resistance sections R1 and R3.

[0054] Furthermore, in the other multiple initial MR elements that will later become the multiple MR elements 50 of the second and fourth resistive sections R2 and R4, by setting the direction of the external magnetic field to the second magnetization direction (-X direction), the magnetization direction of each initial magnetization fixed layer of the other multiple initial MR elements can be fixed to the second magnetization direction. In this way, the multiple MR elements 50 of the second and fourth resistive sections R2 and R4 are formed.

[0055] Next, with reference to Figure 10, the direction of the magnetization 53m of the free layer 53 and its characteristics based on the direction of the magnetization 53m will be explained. Here, we will explain using the case where the magnetization 51m of the magnetization fixed layer 51 includes a component in the first magnetization direction, i.e., the X direction, as an example. Figure 10(a) is a schematic diagram showing the magnetization of a local portion of the magnetization fixed layer 51. Figures 10(b) and 10(c) are schematic diagrams showing the magnetization 53m of the free layer 53.

[0056] As shown in Figures 10(b) and 10(c), there are two stable states for the free layer 53. In the free layer 53 shown in Figure 10(b), the direction of magnetization 53m is stable in a first direction (counterclockwise in Figure 10(b)) that rotates around the center 53c of the magnetic vortex structure when viewed from the stacking direction of the magnetization fixed layer 51 and the free layer 53, i.e., the Z direction. In the free layer 53 shown in Figure 10(c), the direction of magnetization 53m is stable in a second direction (clockwise in Figure 10(c)) that rotates around the center 53c of the magnetic vortex structure in the opposite direction to the first direction when viewed from the Z direction. Hereinafter, the state of the free layer 53 when the direction of magnetization 53m is stable in a state that rotates along the first direction will be referred to as the first state, and the state of the free layer 53 when the direction of magnetization 53m is stable in a state that rotates along the second direction will be referred to as the second state.

[0057] Incidentally, Figure 10(a) shows a magnetized fixed layer 51 formed such that the magnetization 51m of the magnetized fixed layer 51 includes a component in the first magnetization direction, i.e., the X direction. If the direction of the magnetization 51m of the entire magnetized fixed layer 51 is in the X direction, ideally the direction of the magnetization 51ma in each of the multiple local parts of the magnetized fixed layer 51 will also be in the X direction. However, in reality, due to variations in the crystal state, crystal magnetic anisotropy, or shape magnetic anisotropy at the interface, the direction of the magnetization 51ma is dispersed to some extent. Therefore, the magnetization 51m of the magnetized fixed layer 51 actually includes multiple components in different directions. Furthermore, when the direction of the magnetization 51ma is dispersed, there may be a difference in the resistance value of the MR element 50 depending on whether the stable state of the free layer 53 is the first state or the second state.

[0058] Furthermore, the magnetic sensor 1 may be temporarily subjected to an external magnetic field that is not the magnetic field being detected, but which causes the free layer 53 to magnetically saturate. The magnetization 53m of the free layer 53 can be directed in any direction between the first and second directions after such an external magnetic field is applied. In other words, after such an external magnetic field is applied, the stable state of the free layer 53 may change from one of the first and second states to the other.

[0059] Figure 11 is an explanatory diagram showing the relationship between the intensity Hx of the magnetic field component MFx and the resistance value of the MR element 50. In Figure 11, the horizontal axis represents the intensity Hx of the magnetic field component MFx, and the vertical axis represents the resistance value R of the MR element 50. Also in Figure 11, the arrows indicate the trend of change in resistance value when the intensity Hx is changed. Figure 11 schematically shows the resistance value of the MR element 50 when the stable state of the free layer 53 changes from one of the first and second states to the other, after the intensity Hx is increased until the free layer 53 is magnetically saturated and then decreased. As shown in Figure 11, the MR element 50 has a resistance value change characteristic in which the resistance value of the MR element 50 changes at the same intensity Hx depending on the stable state of the free layer 53.

[0060] Here, the resistance change amount ΔR is defined as a parameter that has a correspondence with the resistance change characteristics. The resistance change amount ΔR is a parameter defined for each MR element 50. In this embodiment, when the intensity Hx of the magnetic field component MFx is set to a specific intensity (for example, zero), the resistance change amount ΔR is the value obtained by subtracting the resistance value when the state of the free layer 53 is not the current state (for example, the first state) (for example, the second state) from the current resistance value.

[0061] The resistance change ΔR is ideally zero. However, due to the directional dispersion of the magnetization 51ma mentioned above, the resistance change ΔR may not be zero. Furthermore, the directional dispersion of the magnetization 51ma may differ for each MR element 50. Therefore, the resistance change ΔR may differ for each MR element 50.

[0062] Figure 12 is an explanatory diagram showing the statistical distribution of the resistance change ΔR. In Figure 12, the horizontal axis represents the resistance change ΔR, and the vertical axis represents the number N of MR elements 50. Hereinafter, an MR element 50 whose current state of the free layer 53 is the first state will be called the first MR element 50A, and an MR element 50 whose current state of the free layer 53 is the second state will be called the second MR element 50B. In Figure 12, the curve labeled 81 shows the statistical distribution (first distribution) of the resistance change ΔR for the first group, which is a group of multiple first MR elements 50A. The curve labeled 82 shows the statistical distribution (second distribution) of the resistance change ΔR for the second group, which is a group of multiple second MR elements 50B. The curve labeled 83 shows the statistical distribution (third distribution) of the resistance change ΔR for the third group, which is a group containing both the first MR elements 50A and the second MR elements 50B.

[0063] As shown in Figure 12, the first group has the characteristic that the statistical distribution of the resistance change ΔR is a first distribution 81 centered on a first value ΔR1. The second group has the characteristic that the statistical distribution of the resistance change ΔR is a second distribution 82 centered on a second value ΔR2. The first value ΔR1 may be the average value of the resistance change ΔR of the first group. Similarly, the second value ΔR2 may be the average value of the resistance change ΔR of the second group.

[0064] Figure 12 shows an example where the first value ΔR1 is positive, the second value ΔR2 is negative, and ΔR2 is equal to or approximately equal to -ΔR1. The following explanation is based on the assumptions shown in Figure 12.

[0065] The third group has the characteristic that the statistical distribution of the resistance change ΔR follows a third distribution 83 centered on a third value between the first value ΔR1 and the second value ΔR2. The third value may be the average value of the resistance change ΔR of the third group. The third value is smaller than (ideally zero) the absolute value of the first value ΔR1| |ΔR1| and the absolute value of the second value ΔR2| |ΔR2|.

[0066] In this embodiment, the first to fourth resistors R1 to R4 are configured based on the characteristics of the third group described above. Each of the first to fourth resistors R1 to R4 includes a plurality of first MR elements 50A and a plurality of second MR elements 50B. The plurality of first MR elements 50A and the plurality of second MR elements 50B constituting the first resistor R1 are mixed and electrically connected in the element arrangement region A1 (see Figure 1). In the first resistor R1, it is preferable that the total number of first MR elements 50A and the plurality of second MR elements 50B is even.

[0067] The above description of the first resistor R1 also applies to the second through fourth resistors R2 to R4. If the first resistor R1 and element placement region A1 in the above description of the first resistor R1 are replaced with the second resistor R2 and element placement region A2, respectively, it becomes a description of the second resistor R2. Similarly, if the first resistor R1 and element placement region A1 in the above description of the first resistor R1 are replaced with the third resistor R3 and element placement region A3, respectively, it becomes a description of the third resistor R3. Furthermore, if the first resistor R1 and element placement region A1 in the above description of the first resistor R1 are replaced with the fourth resistor R4 and element placement region A4, respectively, it becomes a description of the fourth resistor R4.

[0068] Next, the operation and effects of the magnetic sensor 1 according to this embodiment will be described. As mentioned above, in this embodiment, multiple first MR elements 50A and multiple second MR elements 50B are electrically connected in the first to fourth resistive sections R1 to R4. As a result, according to this embodiment, it is possible to suppress fluctuations in characteristics caused by the direction of the magnetization 53m of the free layer 53. The effects of this embodiment will be described in detail below.

[0069] When an external magnetic field that causes magnetic saturation of the free layer 53 is temporarily applied to multiple first MR elements 50A of the first resistor R1, the following first, second, and third cases can be considered. The first case is when the stable state of the free layer 53 changes from the first state to the second state in all or almost all of the multiple first MR elements 50A. In the first case, the stable state of the free layer 53 changes from the second state to the first state in all or almost all of the multiple second MR elements 50B of the first resistor R1. That is, in the first case, all or almost all of the multiple first MR elements 50A are replaced by second MR elements 50B, and all or almost all of the multiple second MR elements 50B are replaced by first MR elements 50A.

[0070] The second case is one in which the stable state of the free layer 53 changes from the first state to the second state in a certain number of the multiple first MR elements 50A. In the second case, among the multiple second MR elements 50B of the first resistor R1, the stable state of the free layer 53 changes from the second state to the first state in the same or approximately the same number of second MR elements 50B as the number of first MR elements 50A whose stable state of the free layer 53 changed from the first state to the second state. In other words, in the second case, the same number of first MR elements 50A and second MR elements 50B are swapped.

[0071] The third case is one in which the stable state of the free layer 53 does not change from the first state in all or almost all of the multiple first MR elements 50A. In the third case, the stable state of the free layer 53 does not change from the second state in all or almost all of the multiple second MR elements 50B of the first resistor R1.

[0072] As described above, in any of the first to third cases, ideally, the number of multiple first MR elements 50A and the number of multiple second MR elements 50B in the entire first resistive section R1 does not change or hardly changes before and after an external magnetic field that causes magnetic saturation of the free layer 53 is temporarily applied. In this embodiment, the number of multiple first MR elements 50A and the number of multiple second MR elements 50B are controlled by controlling the stable state of the free layer 53. As a result, in this embodiment, both the change in the number of multiple first MR elements 50A and the change in the number of multiple second MR elements 50B are reduced compared to when the stable state of the free layer 53 is not controlled. Therefore, in this embodiment, the change in the statistical distribution of the resistance change amount ΔR of the multiple first MR elements 50A and the multiple second MR elements 50B constituting the first resistive section R1 is reduced before and after an external magnetic field that causes magnetic saturation of the free layer 53 is temporarily applied. Therefore, in this embodiment, before and after an external magnetic field that causes magnetic saturation of the free layer 53 is temporarily applied, the change in the average value of the resistance change amount ΔR of the plurality of first MR elements 50A and plurality of second MR elements 50B constituting the first resistive section R1 also becomes smaller.

[0073] The average value of the resistance change ΔR of the multiple first MR elements 50A and multiple second MR elements 50B constituting the first resistive section R1 corresponds to the amount of change in the resistance value of the first resistive section R1 when an external magnetic field that magnetically saturates the free layer 53 is temporarily applied. Specifically, the amount of change in the resistance value of the first resistive section R1 decreases as the average value of the resistance change ΔR decreases. Therefore, according to this embodiment, the amount of change in the resistance value of the first resistive section R1 can be reduced.

[0074] The above description of the first resistor R1 also applies to the second to fourth resistors R2 to R4. Therefore, according to this embodiment, the amount of variation in the resistance values ​​of each of the second to fourth resistors R2 to R4 can be reduced.

[0075] Furthermore, according to this embodiment, since the amount of variation in the resistance values ​​of each of the first to fourth resistive sections R1 to R4 can be reduced, the amount of variation in at least one detection signal before and after an external magnetic field that causes magnetic saturation of the free layer 53 is temporarily applied, and the amount of variation in at least one detection signal when the intensity Hx of the magnetic field component MFx is at a specific intensity can be reduced. In this way, according to this embodiment, it is possible to suppress variations in characteristics caused by the direction of the magnetization 53m of the free layer 53.

[0076] Furthermore, it is preferable that the number of MR elements 50 constituting each of the first to fourth resistors R1 to R4 be somewhat large. Here, similar to the MR elements 50, the resistance change amount ΔR is also defined for the total resistance value of any one of the first to fourth resistors R1 to R4. Figure 13 is an explanatory diagram showing the statistical distribution of the resistance change amount ΔR of one resistor. The curve indicated by reference numeral 84 shows the distribution when the number of MR elements 50 included in one resistor is relatively small, and the curve indicated by reference numeral 85 shows the distribution when the number of MR elements 50 included in one resistor is relatively large. Distribution 85 has a smaller width than distribution 84. From the so-called central limit theorem, as the number of MR elements 50 increases, the statistical distribution of the resistance change amount ΔR of one resistor approaches a normal distribution centered on zero, and the standard deviation of the distribution decreases.

[0077] If each of the multiple MR elements 50 is configured such that the free layer 53 does not become magnetically saturated when the intensity Hx of the magnetic field component MFx is within a first range, then at least one detection signal changes within a second range when the intensity Hx of the magnetic field component MFx changes within a first range. The number of MR elements 50 constituting each of the first to fourth resistors R1 to R4 is preferably such that, for example, the amount of variation of at least one detection signal before and after an external magnetic field that causes magnetic saturation of the free layer 53 is temporarily applied is 5% or less, and more preferably 1% or less, of the difference between the maximum and minimum values ​​of the second range when the intensity Hx of the magnetic field component MFx is at a specific intensity.

[0078] Next, a method for controlling the stable state of the free layer 53 will be described. As described above, in this embodiment, a first MR element 50A in which the stable state of the free layer 53 is the first state and a second MR element 50B in which the stable state of the free layer 53 is the second state are mixed together. In this embodiment, the stable state of the free layer 53 is controlled by using at least one of the multiple control methods described below.

[0079] First, the first control method will be described with reference to Figure 14. Figure 14 is a plan view showing an example of the arrangement of MR elements 50. In Figure 14, two MR elements 50 are adjacent to each other with a gap D1 in the direction parallel to the X direction, and this pair of MR elements 50 is adjacent to each other with a gap D2. Also, two MR elements 50 are adjacent to each other with a gap D3 in the direction parallel to the Y direction.

[0080] In the first control method, the spacing D1 is set to a distance that allows the free layers 53 to magnetically couple and interact with each other. This makes it possible to control the free layer 53 of one of the two MR elements 50 to enter a first state and the free layer 53 of the other of the two MR elements 50 to enter a second state, after an external magnetic field that causes magnetic saturation of the free layers 53 is temporarily applied, regardless of the stable state of the free layers 53 of the two MR elements 50.

[0081] In the first control method, by making the interval D3 equal to or approximately equal to the interval D1, it is possible to control the stable states of two adjacent MR elements 50 in the Y direction to be different from each other.

[0082] In this embodiment, the planar shapes of the free layer 53 and the MR element 50, as viewed from the stacking direction of the magnetized fixed layer 51 and the free layer 53, i.e., the Z direction, are circular or nearly circular. Here, the diameter of the planar shape of the MR element 50 is represented by the symbol D, and the film thickness, which is the dimension of the MR element 50 in the stacking direction, is represented by the symbol T. The spacing D1 (spacing D3) may be less than or equal to the estimated spacing determined based on the diameter D and film thickness T. The estimated spacing is the spacing at which the free layers 53 interact with each other at least (the maximum spacing at which the free layers 53 can magnetically couple and interact with each other), and may be the spacing at which the strength of the magnetic field acting on the free layer 53 is several times to more than ten times the strength of the Earth's magnetic field. In one example, the estimated spacing X can be expressed by the following equation (1) using the diameter D and film thickness T. Note that in equation (1), the estimated spacing X is set to the spacing at which the strength of the magnetic field acting on the free layer 53 is 10 times that of the Earth's magnetic field.

[0083]

number

[0084] As shown in equation (1), the estimated interval X is proportional to the 2 / 3 power of the diameter D and proportional to the 1 / 3 power of the film thickness T. It is preferable that interval D1 (or D3) is less than or equal to the estimated interval X. Interval D2 may be equal to interval D1 or greater than or equal to interval D1.

[0085] Next, a second control method will be described with reference to Figure 15. Figure 15 is a plan view showing a free layer 53 to which a structure for controlling the direction of the magnetization 53m of the free layer 53 has been added. In the second control method, the first MR element 50A has a structure 531 for directing the magnetization 53m of the free layer 53 in a first direction. The second MR element 50B has a structure 532 for directing the magnetization 53m of the free layer 53 in a second direction. Each of the structures 531 and 532 may be at least one protruding structure added to the outer edge of the free layer 53. Structures 531 and 532 may satisfy the requirement that the planar shape of structure 531 becomes the planar shape of structure 532 when rotated 180° around the center 53c of the magnetic vortex structure.

[0086] In the MR element 50 having structure 531, the free layer 53 may enter a first stable state after an external magnetic field that causes magnetic saturation of the free layer 53 is temporarily applied. In the MR element 50 having structure 532, the free layer 53 may enter a second stable state after an external magnetic field that causes magnetic saturation of the free layer 53 is temporarily applied.

[0087] Furthermore, the respective functions of structures 531 and 532 are not absolute, but may be relative, with the direction of magnetization 53m being determined by the direction of the external magnetic field.

[0088] Next, the third control method will be described with reference to Figure 16. Figure 16 is a plan view showing a free layer 53 having a planar shape that allows control over the direction of the magnetization 53m of the free layer 53. In the third control method, the free layer 53 has a planar shape that allows control over the direction of the magnetization 53m of the free layer 53 and satisfies the following requirement. That is, in the third control method, the first MR element 50A and the second MR element 50B satisfy the requirement that the planar shape of the first MR element 50A becomes the planar shape of the second MR element 50B when the planar shape of the first MR element 50A is rotated 180° around the center 53c of the magnetic vortex structure. In the example shown in Figure 16, the planar shapes of the first MR element 50A and the second MR element 50B are pentagons.

[0089] Furthermore, the function of the planar shapes of the first MR element 50A and the second MR element 50B is not absolute, but rather relative, where the direction of magnetization 53m is determined by the direction of the external magnetic field. Also, the planar shapes of the first MR element 50A and the second MR element 50B may be polygons other than pentagons (for example, polygons with 24 or more sides).

[0090] Next, a fourth control method will be described with reference to Figure 17. Figure 17 is a plan view showing a first structure that controls the direction of the magnetization 53m of the MR element 50 and the free layer 53. In the fourth control method, the magnetic sensor 1 includes a first structure 70 that controls the direction of the magnetization 53m of the free layer 53. The first structure 70 may be a yoke made of magnetic material placed between two MR elements 50.

[0091] In the fourth control method, when an external magnetic field is temporarily applied to the MR element 50 and the first structure 70 to magnetically saturate the free layer 53, the first structure 70 is magnetized. Figure 17 shows an example where an external magnetic field is applied in the Y direction. This generates a magnetic field from the first structure 70 that controls the direction of the magnetization 53m of the free layer 53. As a result, the stable state of the free layer 53 of one of the two MR elements 50 can become the first state, and the stable state of the free layer 53 of the other of the two MR elements 50 can become the second state.

[0092] Furthermore, the function of the first structure 70 may not be absolute, but rather relative, with the direction of magnetization 53m being determined by the direction of the external magnetic field.

[0093] Next, a fifth control method will be described with reference to Figure 18. Figure 18 is a plan view showing a second structure that controls the direction of the magnetization 53m of the MR element 50 and the free layer 53. In the fifth control method, the magnetic sensor 1 is equipped with second structures 70A and 70B that control the direction of the magnetization 53m of the free layer 53. The second structure 70A is a yoke made of a magnetic material and provided around the free layer 53, and has a structure for directing the magnetization 53m of the free layer 53 in a first direction. The second structure 70B is a yoke made of a magnetic material and provided around the free layer 53, and has a structure for directing the magnetization 53m of the free layer 53 in a second direction. The second structures 70A and 70B may satisfy the requirement that the planar shape of the second structure 70A becomes the planar shape of the second structure 70B when rotated 180° around the center 53c of the magnetic vortex structure.

[0094] Furthermore, the functions of the second structures 70A and 70B are not absolute, but rather relative, with the direction of magnetization 53m being determined by the direction of the external magnetic field.

[0095] Next, a sixth control method will be described with reference to Figures 19 and 20. Figure 19 is a schematic diagram illustrating the direction of the current flowing through the MR element 50. Figure 20 is a schematic diagram illustrating the magnetic field generated due to the current flowing through the MR element 50. In this embodiment, the direction of the current I flowing through the MR element 50 is the direction from the lower electrode 41 toward the upper electrode 42, i.e., the Z direction, and the direction from the upper electrode 42 toward the lower electrode 41, i.e., the -Z direction.

[0096] When a current I in the Z direction flows through the MR element 50, a magnetic field Ha is generated in the MR element 50 due to this current I, and as viewed from the Z direction, this magnetic field Ha rotates around the center 53c of the magnetic vortex structure in a first direction (counterclockwise in Figure 20). When a current I in the -Z direction flows through the MR element 50, a magnetic field Hb is generated in the MR element 50 due to this current I, and as viewed from the Z direction, this magnetic field Hb rotates around the center 53c of the magnetic vortex structure in the opposite direction to the first direction (clockwise in Figure 20). In the sixth control method, the magnetic field Ha can cause the free layer 53 to enter a first stable state, and the magnetic field Hb can cause the free layer 53 to enter a second stable state.

[0097] In the sixth control method, in particular, by making the number of MR elements 50 in each of the first to fourth resistors R1 to R4 an even number, and by making the number of MR elements 50 through which current I flows in the Z direction the same as the number of MR elements 50 through which current I flows in the -Z direction, the number of first MR elements 50A and the number of second MR elements 50B can be made the same.

[0098] Furthermore, in the sixth control method, the first MR element 50A and the second MR element 50B are directly connected to one lower electrode 41, and the first MR element 50A and the second MR element 50B are directly connected to one upper electrode 42.

[0099] [Differentiation] Next, first to third modifications of the magnetic sensor 1 according to this embodiment will be described. First, the first modification will be described with reference to Figure 21. Figure 21 is a plan view showing the first modification of the magnetic sensor 1. In the first modification, the plurality of lower electrodes 41 and the plurality of upper electrodes 42 are connected such that the plurality of MR elements 50, the plurality of lower electrodes 41 and the plurality of upper electrodes 42 have a meander shape when viewed from above. In the example shown in Figure 21, each of the plurality of lower electrodes 41 extends in a direction parallel to the Y direction, and each of the plurality of upper electrodes 42 extends in a direction parallel to the X direction. However, the extension direction of each of the plurality of lower electrodes 41 and the extension direction of each of the plurality of upper electrodes 42 are not limited to the example shown in Figure 21, but may extend in two directions that intersect each other.

[0100] Next, a second modification will be described with reference to Figure 22. Figure 22 is a plan view showing a second modification of the magnetic sensor 1. In the second modification, multiple MR elements 50 are arranged such that the distance between two adjacent MR elements 50 in any direction is D4. Specifically, when viewed from the Z direction, multiple MR elements 50 are arranged such that the figure formed by connecting the centroids of three MR elements 50 that are closest to each other forms an equilateral triangle. Comparing the two modifications with the same area of ​​the element arrangement region, the second modification allows for approximately 15% more MR elements compared to the case where multiple elements are arranged in a grid in both the direction parallel to the X direction and the direction parallel to the Y direction.

[0101] In the example shown in Figure 22, the lower electrode 41 extends in a direction parallel to the direction rotated 60° from the X direction to the Y direction. The upper electrode 42 extends in a direction parallel to the direction rotated 30° from the Y direction to the -X direction.

[0102] Next, a third modification will be described with reference to Figure 23. Figure 23 is a plan view showing a third modification of the magnetic sensor 1. In the third modification, the plurality of MR elements 50 include a plurality of pairs, each containing two MR elements 50. The plurality of pairs are connected in series by a plurality of lower electrodes 41 and a plurality of upper electrodes 42. That is, each pair of MR elements 50 in the plurality of pairs is connected in parallel by one lower electrode 41 and one upper electrode 42.

[0103] [Second Embodiment] Next, a second embodiment of the present disclosure will be described with reference to Figure 24. Figure 24 is a side view showing the MR element and shield in this embodiment. The magnetic sensor 1 according to this embodiment includes a shield 60 made of a magnetic material. The shield 60 may be arranged to cover the first to fourth resistive parts R1 to R4 (see Figure 1). The shield 60 may be a single magnetic material or a magnetic material divided into multiple parts.

[0104] The shield 60 is configured to reduce the strength of the applied magnetic field applied to the multiple MR elements 50. Figure 24 shows an example in which the magnetic field component MFx is applied to the magnetic sensor 1. In the example shown in Figure 24, the magnetic field component MFx is applied to the magnetic sensor 1 in an attenuated state.

[0105] Next, the effect of the shield 60 will be explained with reference to Figure 25. Figure 25 is a characteristic diagram showing the relationship between the intensity Hx of the magnetic field component MFx and the detection signal. In Figure 25, the horizontal axis represents the intensity Hx, and the vertical axis represents the magnitude of the detection signal. In particular, Figure 25 shows the potential difference dVout between the first output terminal 13 and the second output terminal 14 (see Figure 2) as the magnitude of the detection signal. Also, reference numeral 91 indicates the relationship between the intensity Hx and the detection signal when the shield 60 is present, and reference numeral 92 indicates the relationship between the intensity Hx and the detection signal when the shield 60 is absent.

[0106] As shown in Figure 25, according to this embodiment, the shield 60 can increase the range (first range) in which the intensity Hx of the magnetic field component MFx can be changed without magnetically saturating the free layer 53.

[0107] Other configurations, operations, and effects in this embodiment are the same as those in the first embodiment.

[0108] This disclosure is not limited to the embodiments described above, and various modifications are possible. For example, the arrangement of the first to fourth resistors R1 to R4 is arbitrary, not limited to the examples shown in each embodiment, as long as the requirements of the claims are met.

[0109] As described above, the magnetic sensor of the first aspect of this disclosure comprises a plurality of first magnetoresistive elements and a plurality of second magnetoresistive elements, and is configured to detect a magnetic field to be detected and generate a detection signal. The plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements are electrically connected. Each of the plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements includes a magnetization-fixed layer having magnetization with a fixed direction, and a free layer that can have a magnetic vortex structure and is configured so that the center of the magnetic vortex structure moves in response to the applied magnetic field, and has a resistance change characteristic in which the resistance value changes when the strength of the applied magnetic field is the same, depending on the stable state of the magnetic vortex structure. The first group, which is a plurality of first magnetoresistive elements, has the characteristic that the statistical distribution of the resistance change amount, which is a parameter corresponding to the resistance change characteristic, is a first distribution centered on a first value. The second group, which is a plurality of second magnetoresistive elements, has the characteristic that the statistical distribution of the resistance change amount is a second distribution centered on a second value different from the first value. A third group, which includes multiple first magnetoresistive elements and multiple second magnetoresistive elements, has the characteristic that the statistical distribution of the resistance change is a third distribution centered on a third value between the first and second values.

[0110] In a magnetic sensor according to a first aspect of this disclosure, each of the plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements may be configured such that the free layer does not become magnetically saturated when the strength of the magnetic field to be detected is within a first range. The detection signal may change within a second range when the strength of the magnetic field to be detected changes within a first range. The third group may have the characteristic that as the number of magnetoresistive elements included in the third group increases, the statistical distribution of the resistance change amount of the resistive section configured by electrically connecting the magnetoresistive elements included in the third group approaches a normal distribution and the standard deviation of the distribution decreases. The number of magnetoresistive elements included in the third group may be the number such that the fluctuation amount of the detection signal before and after an external magnetic field that magnetically saturates the free layer is temporarily applied to the plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements is 5% or less of the difference between the maximum and minimum values ​​of the second range when the strength of the magnetic field to be detected is at a specific strength within the first range.

[0111] Furthermore, in a magnetic sensor according to a first aspect of this disclosure, the free layer of each of the plurality of first magnetoresistive elements may be stabilized such that the direction of magnetization of the free layer is aligned with a first direction that rotates around the center of the magnetic vortex structure, as viewed from the stacking direction of the magnetization-fixed layer and the free layer. The free layer of each of the plurality of second magnetoresistive elements may be stabilized such that the direction of magnetization of the free layer is aligned with a second direction that rotates around the center of the magnetic vortex structure in the opposite direction to the first direction, as viewed from the stacking direction of the magnetization-fixed layer and the free layer. The magnetization of the free layer may be able to be directed in any direction of the first and second directions after an external magnetic field that magnetically saturates the free layer is temporarily applied to the free layer. Each of the plurality of first magnetoresistive elements may have a first structure for directing the magnetization of the free layer in the first direction. Each of the plurality of second magnetoresistive elements may have a second structure for directing the magnetization of the free layer in the second direction. A magnetic sensor according to a first aspect of the present disclosure may further comprise a plurality of structures, each configured to direct the magnetization of the free layer in a first or second direction.

[0112] Furthermore, in the magnetic sensor of the first aspect of this disclosure, the third group may include a plurality of element arrays. Each of the plurality of element arrays may include a plurality of magnetoresistive elements connected in series. The plurality of element arrays may be connected in parallel with one another. Furthermore, the magnetic sensor of the first aspect of this disclosure may further include electrodes. The plurality of first magnetoresistive elements may include a specific first magnetoresistive element directly connected to the electrodes. The plurality of second magnetoresistive elements may include a specific second magnetoresistive element directly connected to the electrodes.

[0113] Furthermore, in the magnetic sensor of the first aspect of this disclosure, the third group may include a plurality of pairs of magnetoresistive elements connected in parallel.

[0114] Furthermore, in a magnetic sensor according to a first aspect of this disclosure, the plurality of first magnetoresistive elements may include a specific first magnetoresistive element. The plurality of second magnetoresistive elements may include a specific second magnetoresistive element that is spaced adjacent to the specific first magnetoresistive element. The planar shape of the free layer, as viewed from the stacking direction of the magnetized fixed layer and the free layer, may be circular. Each of the specific first magnetoresistive element and the specific second magnetoresistive element may have a diameter of its planar shape as viewed from the stacking direction and a film thickness that is a dimension in the stacking direction. The spacing between the specific first magnetoresistive element and the specific second magnetoresistive element may be less than or equal to an estimated spacing defined based on the planar diameter and film thickness.

[0115] Furthermore, the magnetic sensor of the first aspect of this disclosure may further include a substrate having an element arrangement region. A plurality of first magnetoresistive elements and a plurality of second magnetoresistive elements may be arranged in a mixed manner within the element arrangement region.

[0116] Furthermore, in the magnetic sensor of the first aspect of this disclosure, the sum of the number of first magnetoresistive elements and the number of second magnetoresistive elements may be even.

[0117] Furthermore, in the magnetic sensor of the first aspect of this disclosure, the number of magnetoresistive elements included in the third group in which current flows in one direction parallel to the stacking direction of the magnetized fixed layer and the free layer is the same as the number of magnetoresistive elements in which current flows in the opposite direction.

[0118] Furthermore, in the magnetic sensor of the first aspect of this disclosure, the magnetization of the magnetized fixed layer may include a plurality of components in different directions.

[0119] Furthermore, the magnetic sensor of the first aspect of this disclosure may further include a shield configured to reduce the intensity of the applied magnetic field.

[0120] A magnetic sensor according to a second aspect of this disclosure comprises a plurality of magnetoresistive elements and is configured to detect a target magnetic field and generate a detection signal. Each of the plurality of magnetoresistive elements includes a magnetization-fixed layer having magnetization with a fixed direction and a free layer that can have a magnetic vortex structure and is configured so that the center of the magnetic vortex structure moves in response to the applied magnetic field, and has a resistance change characteristic in which the resistance value changes when the strength of the applied magnetic field is the same, depending on the stable state of the magnetic vortex structure. The group of plurality of magnetoresistive elements has the characteristic that the statistical distribution of the resistance change amount, which is a parameter corresponding to the resistance change characteristic, is distributed around a predetermined value. Each of the plurality of magnetoresistive elements is configured so that the free layer does not become magnetically saturated when the strength of the target magnetic field is within a first range. The detection signal changes within a second range when the strength of the target magnetic field changes within a first range. The group has the characteristic that as the number of plurality of magnetoresistive elements increases, the statistical distribution of the resistance change amount of the resistive section configured by electrically connecting the plurality of magnetoresistive elements approaches a normal distribution and the standard deviation of the distribution decreases. The number of magnetoresistive elements is the number such that the fluctuation in the detection signal before and after an external magnetic field that magnetically saturates the free layer is temporarily applied to the multiple magnetoresistive elements is 5% or less of the difference between the maximum and minimum values ​​in the second range, when the strength of the magnetic field to be detected is at a specific strength within the first range. [Explanation of symbols]

[0121] 1...Magnetic sensor, 10...Substrate, 11...Power terminal, 12...Ground terminal, 13...First output terminal, 14...Second output terminal, 40...Wiring, 41...Lower electrode, 42...Upper electrode, 50...MR element, 50A...First MR element, 50B...Second MR element, 51...Magnetic fixed layer, 51m...Magnification, 52...Gap layer, 53...Free layer, 53m...Magnification, 55...Element array, A1~A4...Element placement region, Hx...Intensity, MF...Target magnetic field, MFx...Magnetic field component, R1...First resistive part, R2...Second resistive part, R3...Third resistive part, R4...Fourth resistive part.

Claims

1. A magnetic sensor comprising a plurality of first magnetoresistive elements and a plurality of second magnetoresistive elements, configured to detect a magnetic field to be detected and generate a detection signal, The plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements are electrically connected. Each of the plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements includes a magnetization-fixed layer having magnetization with a fixed direction, and a free layer that can have a magnetic vortex structure and is configured so that the center of the magnetic vortex structure moves in response to the applied magnetic field, and has a resistance value change characteristic in which the resistance value changes when the strength of the applied magnetic field is the same, depending on the stable state of the magnetic vortex structure. The first group, which is a group of multiple first magnetoresistive elements, has the characteristic that the statistical distribution of the resistance change amount, which is a parameter corresponding to the resistance change characteristics, is a first distribution centered on a first value. The second group, which is a group of multiple second magnetoresistive elements, has the characteristic that the statistical distribution of the resistance change is a second distribution centered on a second value different from the first value. A magnetic sensor characterized in that a third group, which includes the plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements, has the characteristic that the statistical distribution of the resistance change amount is a third distribution centered on a third value between the first value and the second value.

2. Each of the plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements is configured such that the free layer does not become magnetically saturated when the strength of the magnetic field to be detected is within a first range. The detection signal changes within a second range when the strength of the magnetic field to be detected changes within a first range. The third group has the characteristic that as the number of magnetoresistive elements included in the third group increases, the statistical distribution of the resistance change in the resistive section formed by electrically connecting the magnetoresistive elements included in the third group approaches a normal distribution and the standard deviation of the distribution decreases. The number of magnetoresistive elements included in the third group is the amount of change in the detection signal before and after an external magnetic field that magnetically saturates the free layer is temporarily applied to the plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements, and is the number such that the amount of change in the detection signal when the strength of the magnetic field to be detected is at a specific strength within the first range is 5% or less of the difference between the maximum and minimum values ​​in the second range, as described in claim 1.

3. The free layer of each of the plurality of first magnetoresistive elements is stabilized such that the direction of magnetization of the free layer is aligned with a first direction that rotates around the center of the magnetic vortex structure, as viewed from the stacking direction of the magnetization-fixed layer and the free layer. The magnetic sensor according to claim 1, characterized in that the free layer of each of the plurality of second magnetoresistive elements is stabilized such that the direction of magnetization of the free layer is aligned with a second direction that rotates in the opposite direction to the first direction around the center of the magnetic vortex structure, as viewed from the stacking direction of the magnetization-fixed layer and the free layer.

4. The magnetic sensor according to claim 3, characterized in that the magnetization of the free layer can be directed in any of the first and second directions after an external magnetic field that causes magnetic saturation of the free layer is temporarily applied to the free layer.

5. Each of the plurality of first magnetoresistive elements has a first structure for directing the magnetization of the free layer in the first direction. The magnetic sensor according to claim 3, characterized in that each of the plurality of second magnetoresistive elements has a second structure for directing the magnetization of the free layer in the second direction.

6. Furthermore, the magnetic sensor according to claim 3 is characterized by comprising a plurality of structures configured to direct the magnetization of the free layer in the first direction or the second direction.

7. The third group described above includes multiple arrays of elements, The magnetic sensor according to claim 1, characterized in that each of the plurality of element arrays includes a plurality of magnetoresistive elements connected in series.

8. The magnetic sensor according to claim 7, characterized in that the plurality of element arrays are connected in parallel with one another.

9. Furthermore, equipped with electrodes, The plurality of first magnetoresistive elements include a specific first magnetoresistive element directly connected to the electrode. The magnetic sensor according to claim 7, characterized in that the plurality of second magnetoresistive elements include a specific second magnetoresistive element directly connected to the electrode.

10. The magnetic sensor according to claim 1, characterized in that the third group includes a plurality of pairs of magnetoresistive elements connected in parallel.

11. The plurality of first magnetoresistive elements include a specific first magnetoresistive element. The magnetic sensor according to claim 1, characterized in that the plurality of second magnetoresistive elements include specific second magnetoresistive elements that are spaced apart and adjacent to the specific first magnetoresistive element.

12. The planar shape of the free layer, when viewed from the stacking direction of the magnetized fixed layer and the free layer, is circular. Each of the specified first magnetoresistive element and the specified second magnetoresistive element has a diameter of its planar shape when viewed from the stacking direction and a film thickness which is a dimension in the stacking direction. The magnetic sensor according to claim 11, characterized in that the distance between the specified first magnetoresistive element and the specified second magnetoresistive element is less than or equal to an estimated distance determined based on the diameter and the film thickness.

13. Furthermore, the substrate includes an element arrangement region, The magnetic sensor according to claim 1, characterized in that the plurality of first magnetoresistive elements and the plurality of second magnetoresistive elements are arranged in a mixed manner in the element arrangement region.

14. The magnetic sensor according to claim 1, characterized in that the sum of the number of the plurality of first magnetoresistive elements and the number of the plurality of second magnetoresistive elements is an even number.

15. The magnetic sensor according to claim 1, characterized in that, among the magnetoresistive elements included in the third group, the number of magnetoresistive elements through which current flows in one direction parallel to the stacking direction of the magnetized fixed layer and the free layer is the same as the number of magnetoresistive elements through which current flows in the direction opposite to the aforementioned one direction.

16. The magnetic sensor according to claim 1, characterized in that the magnetization of the magnetized fixed layer includes a plurality of components in different directions from each other.

17. Furthermore, the magnetic sensor according to claim 1 is characterized by comprising a shield configured to reduce the intensity of the applied magnetic field.

18. A magnetic sensor comprising multiple magnetoresistive elements and configured to detect a target magnetic field and generate a detection signal, Each of the plurality of magnetoresistive elements includes a magnetization-fixed layer having magnetization with a fixed direction, and a free layer that can have a magnetic vortex structure and is configured so that the center of the magnetic vortex structure moves in response to the applied magnetic field, and has a resistance change characteristic in which the resistance value changes when the strength of the applied magnetic field is the same, depending on the stable state of the magnetic vortex structure. The group of multiple magnetoresistive elements has the characteristic that the statistical distribution of the resistance change amount, which is a parameter corresponding to the resistance change characteristics, is centered around a predetermined value. Each of the plurality of magnetoresistive elements is configured such that the free layer does not become magnetically saturated when the strength of the magnetic field to be detected is within a first range. The detection signal changes within a second range when the strength of the magnetic field to be detected changes within a first range. The group has the characteristic that as the number of magnetoresistive elements increases, the statistical distribution of the resistance change in the resistive section formed by electrically connecting the multiple magnetoresistive elements approaches a normal distribution and the standard deviation of the distribution decreases. The number of the plurality of magnetoresistive elements is such that the amount of fluctuation in the detection signal before and after an external magnetic field that magnetically saturates the free layer is temporarily applied to the plurality of magnetoresistive elements is such that the amount of fluctuation in the detection signal when the strength of the magnetic field to be detected is at a specific strength within a first range is 5% or less of the difference between the maximum and minimum values ​​in a second range.

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