Magnetic sensor

Abstract

The invention relates to a magnetic sensor. This magnetic sensor is provided with: at least one MR element; a ferromagnetic layer configured to overlap the at least one MR element when viewed from the first direction; insulating layers disposed on both sides of the at least one MR element in the second direction; and an antiferromagnetic layer disposed over the at least one MR element, the ferromagnetic layer, and the insulating layer. The antiferromagnetic layer includes an antiferromagnetic portion facing the ferromagnetic layer, and a non-facing portion facing the at least one MR element and the insulating layer but not facing the ferromagnetic layer. There is no magnetic layer between the at least one MR element and the antiferromagnetic layer.

Description

Technical Field

[0001] The present invention relates to a magnetic sensor configured to apply a bias magnetic field to a magnetoresistive effect element. Background Art

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

[0003] Among magnetic sensors, there are magnetic sensors having a mechanism for applying a bias magnetic field to a magnetoresistive effect element. The bias magnetic field is used, for example, to make the magnetoresistive effect element linearly respond to the intensity change of the object magnetic field. In addition, in a magnetic sensor using a spin valve type magnetoresistive effect element, the bias magnetic field is also used to single-domainize the free layer and make the magnetization direction of the free layer face a certain direction when there is no object magnetic field.

[0004] As a mechanism for generating a bias magnetic field, a magnetic field generating body formed by laminating an antiferromagnetic layer and a ferromagnetic layer is known. Japanese Patent Application Laid-Open No. 2015-125020 and Japanese Patent Application Laid-Open No. 2016-176911 disclose a magnetic sensor including a magnetoresistive effect element and two magnetic field generating bodies configured to sandwich the magnetoresistive effect element.

[0005] In order to increase the intensity of the bias magnetic field applied to the magnetoresistive effect element, it is preferable to reduce the interval between the magnetoresistive effect element and the magnetic field generating body and increase the magnetic field generating body. For example, it is considered to form an insulating layer integrally around the magnetoresistive effect element, and form a magnetic field generating body on the magnetoresistive effect element and the insulating layer so as to cover the whole of the magnetoresistive effect element, thereby increasing the intensity of the bias magnetic field applied to the magnetoresistive effect element. However, if this is done, there will be a problem that the magnetic layer contained in the magnetic field generating body functions as a shielding member and the sensitivity of the magnetoresistive effect element is reduced. Summary of the Invention

[0006] An object of the present invention is to provide a magnetic sensor capable of suppressing a decrease in the sensitivity of a magnetoresistive effect element.

[0007] The magnetic sensor of the present invention includes: at least one magnetoresistive effect element including a plurality of stacked magnetic films; a first ferromagnetic layer made of a ferromagnetic material and configured to overlap with at least one magnetoresistive effect element when viewed from a first direction orthogonal to the stacking direction of the plurality of magnetic films; an insulating layer made of an insulating material and disposed on both sides of at least one magnetoresistive effect element in a second direction orthogonal to the stacking direction and the first direction respectively; and an antiferromagnetic layer disposed on at least one magnetoresistive effect element, the first ferromagnetic layer, and the insulating layer. The antiferromagnetic layer includes a first antiferromagnetic portion facing the first ferromagnetic layer, and a non-facing portion facing at least one magnetoresistive effect element and the insulating layer but not facing the first ferromagnetic layer. There is no magnetic layer between at least one magnetoresistive effect element and the antiferromagnetic layer.

[0008] In the magnetic sensor of the present invention, the antiferromagnetic layer is disposed on at least one magnetoresistive effect element, the first ferromagnetic layer, and the insulating layer. The antiferromagnetic layer includes a first antiferromagnetic portion facing the first ferromagnetic layer, and a non-facing portion facing at least one magnetoresistive effect element and the insulating layer but not facing the first ferromagnetic layer. There is no magnetic layer between at least one magnetoresistive effect element and the antiferromagnetic layer. Thus, according to the present invention, a decrease in the sensitivity of the magnetoresistive effect element can be suppressed.

[0009] Other objects, features, and advantages of the present invention will become fully apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a perspective view of a magnetic sensor device including the magnetic sensor according to the first embodiment of the present invention.

[0011] Figure 2 is a functional block diagram showing the structure of the magnetic sensor device according to the first embodiment of the present invention.

[0012] Figure 3 is a circuit diagram showing the circuit structure of the magnetic sensor according to the first embodiment of the present invention.

[0013] Figure 4 is a perspective view of a part of the first detection circuit according to the first embodiment of the present invention.

[0014] Figure 5 is a top view of a part of the first detection circuit according to the first embodiment of the present invention.

[0015] Figure 6 is a top view of a part of the second detection circuit according to the first embodiment of the present invention.

[0016] Figure 7It is a top view of the main part of the magnetic sensor according to the first embodiment of the present invention.

[0017] Figure 8 It is a top view of the magnetoresistive effect element, the magnetic field generating body, and the insulating layer in the first embodiment of the present invention.

[0018] Figure 9 It shows Figure 7 A partial cross-sectional view of the position indicated by line 9-9 in

[0019] Figure 10 It shows Figure 7 A partial cross-sectional view of the position indicated by line 10-10 in

[0020] Figure 11 It is a cross-sectional view showing the formation method of the magnetic field generating body of the comparative example.

[0021] Figure 12A and Figure 12B It is a cross-sectional view showing the formation method of the magnetic field generating body in the first embodiment of the present invention.

[0022] Figure 13 It is a top view of the main part of the first modification of the magnetic sensor according to the first embodiment of the present invention.

[0023] Figure 14 It is a top view of the main part of the second modification of the magnetic sensor according to the first embodiment of the present invention.

[0024] Figure 15 It is a top view of the main part of the third modification of the magnetic sensor according to the first embodiment of the present invention.

[0025] Figure 16 It is a cross-sectional view of the main part of the fourth modification of the magnetic sensor according to the first embodiment of the present invention.

[0026] Figure 17 It is a cross-sectional view of the main part of the fifth modification of the magnetic sensor according to the first embodiment of the present invention.

[0027] Figure 18 It is a cross-sectional view of the main part of the sixth modification of the magnetic sensor according to the first embodiment of the present invention.

[0028] Figure 19 It is a cross-sectional view of the main part of the seventh modification of the magnetic sensor according to the first embodiment of the present invention.

[0029] Figure 20 It is a perspective view of a magnetic sensor system including the magnetic sensor according to the second embodiment of the present invention.

[0030] Figure 21 This is a circuit diagram showing the circuit structure of the magnetic sensor according to the second embodiment of the present invention.

[0031] Figure 22 This is a perspective view showing a part of the magnetic sensor according to the second embodiment of the present invention.

[0032] Figure 23 This is a top view showing a part of the magnetic sensor according to the second embodiment of the present invention.

[0033] Figure 24 This is a side view showing a part of the magnetic sensor according to the second embodiment of the present invention.

[0034] Figure 25 This is a top view showing the main part of the magnetic sensor according to the second embodiment of the present invention.

[0035] Figure 26 This shows Figure 25 A partial cross-sectional view of the position indicated by line 26-26 in

[0036] Figure 27 This shows Figure 25 A partial cross-sectional view of the position indicated by line 27-27 in

[0037] Figure 28 This is a top view showing the main part of the magnetic sensor according to the third embodiment of the present invention.

[0038] Figure 29 This shows Figure 28 A partial cross-sectional view of the position indicated by line 29-29 in

[0039] Figure 30 This shows Figure 28 A partial cross-sectional view of the position indicated by line 30-30 in Detailed Embodiment

[0040] [First Embodiment]

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, with reference to Figure 1 and Figure 2 the structure of the magnetic sensor device including the magnetic sensor according to the first embodiment of the present invention will be described. Figure 1 This is a perspective view showing the magnetic sensor device of the present embodiment. Figure 2 This is a functional block diagram showing the structure of the magnetic sensor device of the present embodiment.

[0042] The magnetic sensor device 100 of the present embodiment includes the magnetic sensor 1 and the processor 2 of the present embodiment. The magnetic sensor 1 is configured to detect the magnetic field of the detection object of the magnetic sensor 1, that is, the object magnetic field, and generate at least one detection signal. The magnetic sensor 1 can be a geomagnetic sensor for detecting geomagnetism, a magnetic sensor for an angle sensor or a magnetic encoder for detecting a rotating magnetic field, or a magnetic sensor for a current sensor for detecting the magnetic field generated by a detected current.

[0043] The processor 2 is configured to generate at least one detection value having a corresponding relationship with the object magnetic field based on at least one detection signal. The processor 2 is constituted by, for example, an application specific integrated circuit (ASIC).

[0044] The magnetic sensor 1 and the processor 2 each have the form of a rectangular parallelepiped-shaped chip. The magnetic sensor 1 has an upper surface 1a and a lower surface 1b located on opposite sides, and four side surfaces connecting the upper surface 1a and the lower surface 1b. The processor 2 includes an upper surface 2a and a lower surface 2b located on opposite sides, and four side surfaces connecting the upper surface 2a and the lower surface 2b. The magnetic sensor 1 is mounted on the upper surface 2a of the processor 2 in a posture where the lower surface 1b of the magnetic sensor 1 faces the upper surface 2a of the processor 2. The magnetic sensor 1 is joined to the processor 2 by, for example, an adhesive.

[0045] Here, as Figure 1 shown, the X direction, the Y direction, and the Z direction are defined. The X direction, the Y direction, and the Z direction are orthogonal to each other. In the present embodiment, the direction perpendicular to the upper surface 1a of the magnetic sensor 1 and the direction from the lower surface 1b of the magnetic sensor 1 toward the upper surface 1a is set as the Z direction. In addition, the direction opposite to the X direction is set as the -X direction, the direction opposite to the Y direction is set as the -Y direction, and the direction opposite to the Z direction is set as the -Z direction.

[0046] Hereinafter, the position in front of the reference position in the Z direction is referred to as "above", and the position on the opposite side of the "above" with respect to the reference position is referred to as "below". In addition, with respect to the constituent elements of the magnetic sensor 1, the surface located at one end in the Z direction is referred to as the "upper surface", and the surface located at one end in the -Z direction is referred to as the "lower surface". In addition, the expression "when viewed from a specified direction (for example, the Z direction)" means observing an object from a position separated in a specified direction or a direction parallel to the specified direction.

[0047] The magnetic sensor 1 has a plurality of first pads (electrode pads) provided on the upper surface 1a. The processor 2 has a plurality of second pads (electrode pads) provided on the upper surface 2a. In the magnetic sensor 1, two corresponding pads among the plurality of first pads and the plurality of second pads are connected to each other by bonding wires.

[0048] The magnetic sensor 1 includes a first detection circuit 10 and a second detection circuit 20. The first and second detection circuits 10, 20 and the processor 2 are connected via a plurality of first pads, a plurality of second pads, and a plurality of bonding wires.

[0049] The first and second detection circuits 10, 20 each include a plurality of magnetic detection elements. In the present embodiment, in particular, the plurality of magnetic detection elements are a plurality of magnetoresistive elements. Hereinafter, the magnetoresistive element will be referred to as an MR element.

[0050] The first detection circuit 10 detects the component of the object magnetic field parallel to the X direction and generates at least one first detection signal having a corresponding relationship with this component. The second detection circuit 20 detects the component of the object magnetic field parallel to the Y direction and generates at least one second detection signal having a corresponding relationship with this component.

[0051] Next, with reference to Figure 3 the circuit structure of the magnetic sensor 1 will be described. Figure 3 is a circuit diagram showing the circuit structure of the magnetic sensor 1.

[0052] The first detection circuit 10 includes four resistor portions R11, R12, R13, R14, a power supply port V1, a ground port G1, and two output ports E11, E12. The resistor portion R11 is provided between the power supply port V1 and the output port E11. The resistor portion R12 is provided between the output port E11 and the ground port G1. The resistor portion R13 is provided between the output port E22 and the ground port G2. The resistor portion R14 is provided between the power supply port V1 and the output port E22. A voltage or current of a specified magnitude is applied to the power supply port V1. The ground port G1 is grounded.

[0053] The second detection circuit 20 includes four resistor portions R21, R22, R23, R24, a power supply port V2, a ground port G2, and two output ports E21, E22. The resistor portion R21 is provided between the power supply port V2 and the output port E21. The resistor portion R22 is provided between the output port E21 and the ground port G2. The resistor portion R23 is provided between the output port E22 and the ground port G2. The resistor portion R24 is provided between the power supply port V2 and the output port E22. A voltage or current of a specified magnitude is applied to the power supply port V2. The ground port G2 is grounded.

[0054] Next, with reference to Figures 4 - 6 the structures of the first and second detection circuits 10, 20 will be described respectively. Figure 4 is a perspective view showing a part of the first detection circuit 10. Figure 5 is a top view showing a part of the first detection circuit 10. Figure 6 is a top view showing a part of the second detection circuit 20.

[0055] The magnetic sensor 1 further includes a substrate 30. The magnetic sensor 1 is constituted by forming a plurality of components other than the substrate 30 on the substrate 30. The first detection circuit 10 and the second detection circuit 20 are provided on the substrate 30. The resistance portions R11 to R14 each include a plurality of MR elements 50A. The resistance portions R21 to R24 each include a plurality of MR elements 50B.

[0056] The resistance portions R11 to R14 each further include a plurality of lower electrodes 61 and a plurality of upper electrodes 62. As Figure 4 and Figure 5 shown, the plurality of MR elements 50A each have a long shape in a direction parallel to the Y direction. The plurality of lower electrodes 61 each electrically connect two adjacent MR elements 50A in a direction parallel to the X direction. The plurality of upper electrodes 62 are respectively disposed above the two lower electrodes 61 and electrically connect the adjacent two MR elements 50A. Thus, the plurality of MR elements 50A arranged in a row in the direction parallel to the X direction are connected in series.

[0057] The resistance portions R11 to R14 each further include a plurality of connection electrodes (not shown). In each of the resistance portions R11 to R14, the plurality of connection electrodes electrically connect the plurality of lower electrodes 61 or the plurality of upper electrodes 62 so that the groups of the plurality of MR elements 50A arranged in a row are connected in series. With such a structure, the resistance portions R11 to R14 each include a plurality of lower electrodes 61, a plurality of upper electrodes 62, and a plurality of MR elements 50A connected in series by the plurality of connection electrodes.

[0058] The above description of the connection relationship of the plurality of MR elements 50A basically also applies to the plurality of MR elements 50B in each of the resistance portions R21 to R24. As Figure 6 shown, in each of the resistance portions R21 to R24, the plurality of MR elements 50B each have a long shape in a direction parallel to the X direction. If the plurality of MR elements 50A, the X direction, and the Y direction in the above description of the connection relationship of the plurality of MR elements 50A are respectively replaced with the plurality of MR elements 50B, the Y direction, and the X direction, it becomes a description of the connection relationship of the plurality of MR elements 50B.

[0059] The resistance portions R11 to R14 each further include a plurality of magnetic field generators 70A. The plurality of magnetic field generators 70A each include pairs of the plurality of magnetic field generators 70A constituted by two magnetic field generators 70A. The above two magnetic field generators 70A are arranged at a predetermined interval in a direction parallel to the Y direction so as to sandwich one MR element 50A. The two magnetic field generators 70A are configured to apply a bias magnetic field to one MR element 50A located therebetween. The bias magnetic field may include a component in the direction parallel to the Y direction as a main component.

[0060] The resistance units R21 to R24 each further include a plurality of magnetic field generating bodies 70B. The plurality of magnetic field generating bodies 70B each include a pair of a plurality of magnetic field generating bodies 70B each composed of two magnetic field generating bodies 70B. The above two magnetic field generating bodies 70B are arranged at a predetermined interval in a direction parallel to the X direction with one MR element 50B interposed therebetween. The two magnetic field generating bodies 70B are configured to apply a bias magnetic field to one MR element 50B located therebetween. The bias magnetic field may also include a component in the direction parallel to the X direction as a main component.

[0061] As Figure 4 shown, the plurality of magnetic field generating bodies 70A may also be respectively clamped between the lower electrode 61 and the upper electrode 62. Although not shown, the plurality of magnetic field generating bodies 70B may also be respectively clamped between the lower electrode 61 and the upper electrode 62.

[0062] In the present embodiment, the plurality of MR elements 50A and the plurality of MR elements 50B are each a spin valve type MR element. The spin valve type MR element includes: a magnetization fixed layer having a magnetization with a fixed direction, a free layer having a magnetization whose direction can vary according to the direction of an object magnetic field, and a spacer layer disposed between the magnetization fixed layer and the free layer. The spin valve type MR element may be a TMR (tunnel magnetoresistance effect) element or a GMR (giant magnetoresistance effect) element. In the TMR element, the spacer layer is a tunnel barrier layer. In the GMR element, the spacer layer is a nonmagnetic conductive layer. In the spin valve type MR element, the resistance value varies according to the angle formed by the magnetization direction of the free layer and the magnetization direction of the magnetization fixed layer. When the angle is 0°, the resistance value becomes the minimum, and when the angle is 180°, the resistance value becomes the maximum. In each MR element, the free layer has a shape anisotropy in which the direction of the easy magnetization axis becomes orthogonal to the magnetization direction of the magnetization fixed layer.

[0063] The spin valve type MR element may further include an antiferromagnetic layer. The antiferromagnetic layer is made of an antiferromagnetic material and generates an exchange coupling with the magnetization fixed layer to fix the magnetization direction of the magnetization fixed layer. In addition, the magnetization fixed layer may be a so-called self-pinned type fixed layer (Synthetic Ferri Pinned layer, SFP layer). The self-pinned type fixed layer has a stacked ferrite structure in which a ferromagnetic layer, a nonmagnetic intermediate layer, and a ferromagnetic layer are stacked, and is formed by antiferromagnetically coupling two ferromagnetic layers. When the magnetization fixed layer is a self-pinned type fixed layer, the antiferromagnetic layer may be omitted.

[0064] Next, with reference to Figure 3 the magnetization direction of the magnetization fixed layer and the direction of the bias magnetic field will be described. In Figure 3Among them, a plurality of solid arrows respectively depicted in a manner overlapping with the resistance portions R11 to R14 and R21 to R24 represent the magnetization directions of the magnetization fixed layers in each of the resistance portions R11 to R14 and R21 to R24. In Figure 3 In the example shown, the directions of the main components of the magnetization of the magnetization fixed layers in each of the resistance portions R11 and R13 are in the X direction. The directions of the main components of the magnetization of the magnetization fixed layers in each of the resistance portions R12 and R14 are in the -X direction. Each of the free layers in the resistance portions R11 to R14 has shape anisotropy in which the direction of the easy magnetization axis is parallel to the Y direction.

[0065] The directions of the main components of the magnetization of the magnetization fixed layers in each of the resistance portions R21 and R23 are in the Y direction. The directions of the main components of the magnetization of the magnetization fixed layers in each of the resistance portions R22 and R24 are in the -Y direction. Each of the free layers in the resistance portions R21 to R24 has shape anisotropy in which the direction of the easy magnetization axis is parallel to the X direction.

[0066] In Figure 3 Among them, the arrows marked with symbols M11, M12, M13, and M14 respectively represent the directions of the main components of the bias magnetic fields generated by the plurality of magnetic field generators 70A in the resistance portions R11, R12, R13, and R14. The directions of the main components of the bias magnetic fields in the resistance portions R11 and R12 are in the Y direction. The directions of the main components of the bias magnetic fields in the resistance portions R13 and R14 are in the -Y direction.

[0067] In Figure 3 Among them, a plurality of hollow arrows respectively depicted in a manner overlapping with the resistance portions R11 to R14 represent the magnetization directions of the free layers in each of the resistance portions R11 to R14 when no object magnetic field is applied to the magnetic sensor 1. The directions of the main components of the magnetization of the free layers in each of the resistance portions R11 and R12 are in the Y direction, which is the same as the direction of the main component of the bias magnetic field in the resistance portions R11 and R12. The directions of the main components of the magnetization of the free layers in each of the resistance portions R13 and R14 are in the -Y direction, which is the same as the direction of the main component of the bias magnetic field in the resistance portions R13 and R14.

[0068] In Figure 3 Among them, the arrows marked with symbols M21, M22, M23, and M24 respectively represent the directions of the main components of the bias magnetic fields generated by the plurality of magnetic field generators 70B in the resistance portions R21, R22, R23, and R24. The directions of the main components of the bias magnetic fields in the resistance portions R21 and R22 are in the X direction. The directions of the main components of the bias magnetic fields in the resistance portions R23 and R24 are in the -X direction.

[0069] In Figure 3In [the figure], a plurality of hollow arrows depicted so as to overlap with the resistance portions R21 to R24 respectively indicate the magnetization directions of the free layers in each of the resistance portions R21 to R24 when no object magnetic field is applied to the magnetic sensor 1. The directions of the main components of the magnetization of the free layers in each of the resistance portions R21 and R22 are in the X direction, which is the same as the direction of the main component of the bias magnetic field in the resistance portions R21 and R22. The directions of the main components of the magnetization of the free layers in each of the resistance portions R23 and R24 are in the -X direction, which is the same as the direction of the main component of the bias magnetic field in the resistance portions R23 and R24.

[0070] In addition, the magnetization direction may coincide with the direction of the main component of the magnetization described above, or may deviate slightly from the direction of the main component of the magnetization. Similarly, the direction of the bias magnetic field may coincide with the direction of the main component of the bias magnetic field described above, or may deviate slightly from the direction of the main component of the bias magnetic field. In the following description, it is assumed that the magnetization direction coincides with the direction of the main component of the magnetization, and it is assumed that the direction of the bias magnetic field coincides with the direction of the main component of the bias magnetic field.

[0071] Next, with reference to Figure 3 The operations of the first and second detection circuits 10 and 20 will be described. In the first detection circuit 10, the potential of the connection point of the resistance portions R11 and R12, that is, the potential of the output port E11, and the potential of the connection point of the resistance portions R13 and R14, that is, the potential of the output port E12, vary according to the intensity of the component of the object magnetic field in the direction parallel to the X direction. The first detection circuit 10 may also generate a signal corresponding to the potential of the output port E11 and a signal corresponding to the potential of the output port E12 as first detection signals, respectively. Alternatively, the first detection circuit 10 may generate a signal corresponding to the potential difference between the output ports E11 and E12 as a first detection signal. In this case, the first detection circuit 10 may also include a differential amplifier (differential detector) that outputs a signal corresponding to the potential difference between the output ports E11 and E12 as a first detection signal.

[0072] In the second detection circuit 20, the potential of the connection point of the resistance portions R21 and R22, that is, the potential of the output port E21, and the potential of the connection point of the resistance portions R23 and R24, that is, the potential of the output port E22, vary according to the intensity of the component of the object magnetic field in the direction parallel to the Y direction. The second detection circuit 20 may also generate a signal corresponding to the potential of the output port E21 and a signal corresponding to the potential of the output port E22 as second detection signals, respectively. Alternatively, the second detection circuit 20 may generate a signal corresponding to the potential difference between the output ports E21 and E22 as a second detection signal. In this case, the second detection circuit 20 may also include a differential amplifier (differential detector) that outputs a signal corresponding to the potential difference between the output ports E21 and E22 as a second detection signal.

[0073] Next, with reference to Figures 7 - 10 the structures of the plurality of MR elements 50A, the plurality of MR elements 50B, the plurality of magnetic field generators 70A, and the plurality of magnetic field generators 70B will be described in detail. Figure 7 is a top view showing the main part of the magnetic sensor 1. Figure 8 is a top view showing the MR element, the magnetic field generator, and the insulating layer. Figure 9 is showing Figure 7 a partial cross-sectional view of the position indicated by the line 9-9 in Figure 10 is showing Figure 7 a partial cross-sectional view of the position indicated by the line 10-10 in

[0074] Here, as Figures 7 - 10 shown, a first direction D1 and a second direction D2 that are orthogonal to each other and orthogonal to the Z direction are respectively defined. In the first detection circuit 10, the first direction D1 is a direction parallel to the Y direction, and the second direction D2 is a direction parallel to the X direction. In the second detection circuit 20, the first direction D1 is a direction parallel to the X direction, and the second direction D2 is a direction parallel to the Y direction.

[0075] Hereinafter, the symbol 50 is used to represent any one of the plurality of MR elements 50A and the plurality of MR elements 50B, and the symbol 70 is used to represent any one of the plurality of magnetic field generators 70A and the plurality of magnetic field generators 70B. The magnetic sensor 1 includes at least one MR element 50. In the present embodiment, in particular, the magnetic sensor 1 includes a plurality of MR elements 50 as the at least one MR element 50.

[0076] Here, focusing on one MR element 50, the structures of the MR element 50 and the magnetic field generator 70 will be described. The MR element 50 includes a plurality of magnetic films. The stacking direction of the plurality of magnetic films is a direction parallel to the Z direction. The plurality of magnetic films include the above-described magnetization fixing layer 52 and free layer 54. The plurality of MR elements 50 also respectively include the above-described spacer layer 53, buffer layer 51, and capping layer 55. As Figure 9 [[ID=‘28]]and ​ shown, the buffer layer 51, magnetization fixing layer 52, spacer layer 53, free layer 54, and capping layer 55 are stacked in this order along the Z direction. The buffer layer 51 and the capping layer 55 are each formed of a non-magnetic metal material such as Ru, Ta, Cu, and Cr, for example.

[0077] The MR element 50 has an upper surface 50a at one end in the Z direction, a lower surface 50b at one end in the -Z direction, two side surfaces 50c at both ends in the first direction D1, and two side surfaces 50d at both ends in the second direction D2. The lower surface 50b of the MR element 50 is in contact with the lower electrode 61. Each of the two side surfaces 50c and the two side surfaces 50d is inclined with respect to the lamination direction of the plurality of magnetic films (the direction parallel to the Z direction).

[0078] The magnetic sensor 1 further includes: at least one ferromagnetic layer 72 made of a ferromagnetic material; and an insulating layer 32 made of an insulating material such as Al2O3 or SiO2. The at least one ferromagnetic layer 72 is configured to overlap the MR element 50 when viewed from the first direction D1. In the present embodiment, in particular, the at least one ferromagnetic layer 72 is configured to overlap the entire free layer 54 when viewed from the first direction D1.

[0079] In addition, the at least one ferromagnetic layer 72 is configured to rise to the side surface 50c of the MR element 50. When viewed from the Z direction, a part of the at least one ferromagnetic layer 72 overlaps a part of the MR element 50. The insulating layer 32 is disposed on both sides of the MR element 50 in the second direction D2.

[0080] In the present embodiment, in particular, the MR element 50 is disposed between two ferromagnetic layers 72 disposed at a predetermined interval in the first direction D1. The insulating layer 32 is disposed around the MR element 50 and the two ferromagnetic layers 72.

[0081] The ferromagnetic layer 72 is formed of a ferromagnetic material containing one or more elements of Co, Fe, and Ni. Examples of such a ferromagnetic material include CoFe, CoFeB, and CoNiFe. The ferromagnetic layer 72 may also be composed of a laminate of multiple layers and a laminate in which two adjacent layers are made of different ferromagnetic materials. Examples of such a ferromagnetic layer 72 include a laminate of a Co layer, a CoFe layer, and a Co layer, Co 70 Fe 30 layer, Co 30 Fe 70 layer, Co 70 Fe 30 layer laminate. In addition, Co 70 Fe 30 represents an alloy composed of 70 atomic% Co and 30 atomic% Fe, Co 30 Fe 70 represents an alloy composed of 30 atomic% Co and 70 atomic% Fe.

[0082] The magnetic sensor 1 further includes two buffer layers 71 respectively disposed on the lower surface side (-Z direction side) of a plurality of two ferromagnetic layers 72. The two buffer layers 71 are formed of nonmagnetic metal materials such as Ru, Ta, Cu, and Cr, for example.

[0083] The magnetic sensor 1 further includes: an antiferromagnetic layer 74 disposed above the MR element 50, the two ferromagnetic layers 72, and the insulating layer 32; and a covering layer 75 disposed above the antiferromagnetic layer 74. The antiferromagnetic layer 74 includes two antiferromagnetic portions 74a facing the two ferromagnetic layers 72, and a non-facing portion 74b facing the MR element 50 and the insulating layer 32 but not facing the two ferromagnetic layers 72. The two antiferromagnetic portions 74a are connected to each other through the non-facing portion 74b. There is no magnetic layer between the MR element 50 and the antiferromagnetic layer 74. The covering layer 75 includes two protection portions 75a disposed above the two antiferromagnetic portions 74a.

[0084] The antiferromagnetic layer 74 is formed of an antiferromagnetic material such as IrMn or PtMn, for example. The covering layer 75 is formed of a nonmagnetic metal material such as Ru, Ta, Cu, and Cr, for example.

[0085] The buffer layer 71 and the ferromagnetic layer 72 constitute a first laminate 701. The antiferromagnetic layer 74 and the covering layer 75 constitute a second laminate 702. The MR element 50 is disposed between the two first laminates 701. The second laminate 702 is disposed above the MR element 50, the insulating layer 32, and the two first laminates 701.

[0086] The second laminate 702 includes two laminated portions 702a disposed above the two first laminates 701. The two laminated portions 702a respectively include the antiferromagnetic portion 74a and the protection portion 75a.

[0087] The ferromagnetic layer 72 has magnetization as a whole of the ferromagnetic layer 72. The magnetization as a whole of the ferromagnetic layer 72 is obtained by volume averaging the vector sum of the magnetic moments per unit of atoms, crystal lattices, etc. in the whole ferromagnetic layer 72. Hereinafter, the magnetization of the ferromagnetic layer 72 as a whole will be simply referred to as the magnetization of the ferromagnetic layer 72. In the laminate composed of the first laminate 701 and the laminated portion 702a disposed above the first laminate 701, the antiferromagnetic portion 74a is in contact with the upper surface of the ferromagnetic layer 72 and is exchange-coupled with the ferromagnetic layer 72. Thereby, the magnetization direction of the ferromagnetic layer 72 is defined. The ferromagnetic layer 72 and the antiferromagnetic portion 74a may also constitute a magnetic field generating body 70 that generates a bias magnetic field applied to the MR element 50 based on the magnetization of the ferromagnetic layer 72. The magnetic field generating body 70 configured in this way has high resistance to interfering magnetic fields.

[0088] The ferromagnetic layer 72 is a part of the first stack 701, and the antiferromagnetic portion 74a is a part of the stacked portion 702a. Therefore, it can also be said that the first stack 701 and the stacked portion 702a constitute the magnetic field generating body 70. The magnetic field generating body 70 includes a buffer layer 71, a ferromagnetic layer 72, an antiferromagnetic portion 74a, and a protective portion 75a. The MR element 50 is disposed between the two magnetic field generating bodies 70. The two magnetic field generating bodies 70 cooperatively apply a bias magnetic field to the MR element 50. The magnetization directions of the ferromagnetic layers 72 of one of the two magnetic field generating bodies 70 and the ferromagnetic layers 72 of the other of the two magnetic field generating bodies 70 may be the same. In this case, the directions of the bias magnetic fields generated by one of the two magnetic field generating bodies 70 and the directions of the bias magnetic fields generated by the other of the two magnetic field generating bodies 70 become the same direction.

[0089] The upper surface 50a of the MR element 50 faces the non-opposing portion 74b of the antiferromagnetic layer 74. The interval between at least a part of the non-opposing portion 74b and the lower surface 50b of the MR element 50 may be the same as the interval between the upper surface 50a and the lower surface 50b. The interval between the antiferromagnetic portion 74a of the antiferromagnetic layer 74 and the upper surface of the lower electrode 61 may be the same as the interval between the non-opposing portion 74b and the lower surface 50b, or may be different from the interval between the non-opposing portion 74b and the lower surface 50b. In the latter case, the maximum interval between the antiferromagnetic portion 74a and the upper surface of the lower electrode 61 may be larger than the interval between the non-opposing portion 74b and the lower surface 50b, or may be smaller than the interval between the non-opposing portion 74b and the lower surface 50b.

[0090] The ferromagnetic layer 72 has a side surface 72a that faces the side surface 50c of the MR element 50. The side surface 72a includes an inclined portion 72a1 that faces the free layer 54 of the MR element 50 and is inclined with respect to the stacking direction of the plurality of magnetic films (the direction parallel to the Z direction). The angle formed by the inclined portion 72a1 and the stacking direction is in the range of 20° or more and 90° or less.

[0091] The magnetic sensor 1 further includes an insulating layer 31 made of an insulating material and interposed between the substrate 30 (refer to ​ ) and the lower electrode 61, and an insulating layer 33 made of an insulating material and interposed between the MR element 50 and the two first stacks 701. The insulating layers 31 and 33 are formed of insulating materials such as Al2O3 and SiO2, for example.

[0092] The upper surface of the second laminate 702, i.e., the upper surface of the cover layer 75, is in contact with the upper electrode 62. The planar shape of the second laminate 702 (the shape observed from the Z direction) may be the same as the planar shape of the upper electrode 62, may be smaller than the planar shape of the upper electrode 62, or may be larger than the planar shape of the upper electrode 62. The magnetic sensor 1 further includes an insulating layer (not shown) made of an insulating material and disposed above the upper electrode 62.

[0093] So far, focusing on one MR element 50, the structures of the MR element 50 and the magnetic field generator 70 have been described. In the present embodiment, the magnetic sensor 1 includes a plurality of MR elements 50. As ​ shown, the plurality of MR elements 50 include two MR elements 50 arranged along the second direction D2. A second laminate 702 is interposed between the two MR elements 50 and the upper electrode 62 that electrically connects the two MR elements 50. In ​ the example shown, the second laminate 702 is disposed above the two MR elements 50 and the four first laminates 701. In this example, the second laminate 702 includes four laminated portions 702a.

[0094] The two MR elements 50 are also electrically connected through the antiferromagnetic layer 74 of the second laminate 702. Additionally, the two MR elements 50 may be connected in series through the antiferromagnetic layer 74.

[0095] Moreover, in the present embodiment, since the magnetic sensor 1 includes a plurality of MR elements 50 and a plurality of magnetic field generators 70, the magnetic sensor 1 includes a plurality of buffer layers 71, a plurality of ferromagnetic layers 72, a plurality of antiferromagnetic layers 74, and a plurality of cover layers 75.

[0096] Next, the operation and effects of the magnetic sensor 1 of the present embodiment will be described. In the present embodiment, the antiferromagnetic layer 74 is disposed above the MR element 50, the two ferromagnetic layers 72, and the insulating layer 32. There is no magnetic layer between the MR element 50 and the antiferromagnetic layer 74. Thus, according to the present embodiment, a decrease in the sensitivity of the MR element 50 can be suppressed.

[0097] Furthermore, in the present embodiment, the antiferromagnetic layer 74 includes an antiferromagnetic portion 74a that exchanges coupling with the ferromagnetic layer 72 and defines the magnetization direction of the ferromagnetic layer 72. As will be described later, in the present embodiment, the base portion of the antiferromagnetic layer 74 is flat or substantially flat, and the antiferromagnetic layer 74 can be formed in a state where no structure is provided above the base portion. Thus, according to the present embodiment, a decrease in the film thickness of the antiferromagnetic portion 74a can be suppressed. As a result, according to the present embodiment, the antiferromagnetic portion 74a can be effectively utilized, and the above functions of the antiferromagnetic portion 74a and the functions of the magnetic field generator 70 can be realized.

[0098] In addition, in the present embodiment, a covering layer 75 is formed over the antiferromagnetic layer 74. The covering layer 75 includes a protection portion 75a that protects the antiferromagnetic portion 74a. According to the present embodiment, by forming the covering layer 75 over the antiferromagnetic layer 74, it is possible to suppress a decrease in the film thickness of the protection portion 75a. Thus, according to the present embodiment, the protection portion 75a can be effectively utilized, and as a result, the above-described function of the protection portion 75a can be achieved.

[0099] Hereinafter, while comparing with a magnetic sensor of a comparative example having a magnetic field generating body of a comparative example, the above-described effects will be described in detail. First, the structure of the magnetic sensor of the comparative example will be described. The magnetic sensor of the comparative example includes a magnetic field generating body 170 of a comparative example instead of the magnetic field generating body 70 in the present embodiment.

[0100] The magnetic field generating body 170 includes a buffer layer 171, a ferromagnetic layer 172, an antiferromagnetic layer 173, and a covering layer 174. The buffer layer 171, the ferromagnetic layer 172, the antiferromagnetic layer 173, and the covering layer 174 respectively correspond to the buffer layer 71, the ferromagnetic layer 72, the antiferromagnetic layer 74, and the covering layer 75 in the present embodiment. In the comparative example, the antiferromagnetic layer 173 is in contact with the upper surface of the ferromagnetic layer 172 and is exchange-coupled with the ferromagnetic layer 172. Thereby, the magnetization direction of the ferromagnetic layer 172 is defined.

[0101] ​ It is a cross-sectional view showing a method of forming the magnetic field generating body of the comparative example. The magnetic field generating body 170 of the comparative example is formed as follows. First, the stacked film that will later become the MR element 50 is patterned, and two side surfaces 50d (see ​ ) are formed on the stacked film. Next, an insulating layer 32 (see ​ and ​ ) is formed around the stacked film.

[0102] Next, as shown in ​ , a photoresist mask 81 is formed over the stacked film. Next, using the photoresist mask 81, the stacked film is patterned by etching so as to form two side surfaces 50c on the stacked film. Thereby, the stacked film becomes the MR element 50.

[0103] Next, with the photoresist mask 81 remaining, an insulating layer 131, a buffer layer 171, a ferromagnetic layer 172, an antiferromagnetic layer 173, and a covering layer 174 are sequentially formed. Thereby, the magnetic field generating body 170 is completed. Next, the photoresist mask 81 is removed. In addition, the photoresist mask 81 may be formed after patterning the MR element 50.

[0104] As shown in ​As shown, due to the influence of the shadow of the photoresist mask 81, the film thickness of the antiferromagnetic layer 173 decreases as it approaches the photoresist mask 81. Therefore, near the corner where the upper surface 50a and the side surface 50c of the MR element 50 intersect, the blocking temperature of the antiferromagnetic layer 173 decreases, and the heat resistance of the antiferromagnetic layer 173 decreases. Therefore, in an environment where the temperature temporarily or permanently becomes high, the functions of the antiferromagnetic layer 173 and the magnetic field generating body 170 cannot be exerted.

[0105] Similarly, due to the influence of the shadow of the photoresist mask 81, the film thickness of the covering layer 174 decreases as it approaches the photoresist mask 81. Therefore, near the above-mentioned corner, the antiferromagnetic layer 173 cannot be sufficiently protected, and the antiferromagnetic layer 173 may be corroded. If the antiferromagnetic layer 173 is corroded, the functions of the antiferromagnetic layer 173 and the magnetic field generating body 170 cannot be exerted.

[0106] In contrast, in the present embodiment, it is possible to suppress the decrease in the film thicknesses of the antiferromagnetic portion 74a and the protective portion 75a, respectively. ​ and ​ is a cross-sectional view showing a method of forming the magnetic field generating body 70 in the present embodiment. The magnetic field generating body 70 in the present embodiment is formed as follows. First, the stacked film that will later become the MR element 50 is patterned, and two side surfaces 50d (refer to ​ ) are formed on the stacked film. Next, an insulating layer 32 (refer to ​ and ​ ) is formed around the stacked film.

[0107] Next, as ​ shown, a photoresist mask 82 is formed on the stacked film. Next, using the photoresist mask 82, the stacked film is patterned by etching so as to form two side surfaces 50c on the stacked film. Thereby, the stacked film becomes the MR element 50. Next, in a state where the photoresist mask 82 remains, the insulating layer 33, the buffer layer 71, and the ferromagnetic layer 72 are sequentially formed.

[0108] Next, as ​ shown, the photoresist mask 82 is removed. Next, the antiferromagnetic layer 74 and the covering layer 75 are sequentially formed on the MR element 50, the ferromagnetic layer 72, and the insulating layer 32. Next, a process of fixing the magnetization direction of the ferromagnetic layer 72 is performed. Thereby, the magnetic field generating body 70 is completed. The process of fixing the magnetization direction of the ferromagnetic layer 72 will be described in detail later.

[0109] As ​As shown, in the present embodiment, the antiferromagnetic layer 74 and the capping layer 75 are formed on the laminate of the MR element 50, the ferromagnetic layer 72, and the insulating layer 32. The upper surface of the laminate is flat or substantially flat. In addition, when forming the antiferromagnetic layer 74 and the capping layer 75, there are no structures such as a photoresist mask on the laminate. Therefore, in the present embodiment, the film thicknesses of the antiferromagnetic layer 74 and the capping layer 75 are constant or substantially constant regardless of the distance from the MR element 50. Thus, according to the present embodiment, it is possible to suppress the reduction in the film thicknesses of the antiferromagnetic portion 74a and the protection portion 75a, respectively. As a result, according to the present embodiment, the antiferromagnetic portion 74a and the protection portion 75a can be effectively utilized.

[0110] In addition, in the present embodiment, the insulating layer 32 has a function of suppressing the film thickness variation of the layers formed on the MR element 50. That is, if the insulating layer 32 does not exist, a part of each of the antiferromagnetic layer 74 and the capping layer 75 is formed along the two side surfaces 50d of the MR element 50. In this case, the film thicknesses of the layers formed along the two side surfaces 50d of the MR element 50 may be different from the film thicknesses of the layers formed along the upper surface 50a of the MR element 50 and the upper surface of the ferromagnetic layer 72. In contrast, according to the present embodiment, by forming each of the antiferromagnetic layer 74 and the capping layer 75 along the upper surface 50a of the MR element 50, the upper surface of the ferromagnetic layer 72, and the upper surface of the insulating layer 32, the film thickness variation of each layer can be suppressed. Furthermore, by forming each of the antiferromagnetic layer 74 and the capping layer 75 by a method with good step coverage, the film thickness variation of each layer can be more effectively suppressed. Accordingly, according to the present embodiment, the antiferromagnetic portion 74a and the protection portion 75a can also be effectively used.

[0111] Next, a method for forming a plurality of MR elements 50 in the present embodiment will be briefly described. In the process of forming a plurality of MR elements 50, first, a plurality of initial MR elements that will become a plurality of MR elements 50 are formed. Each of the plurality of initial MR elements includes an initial magnetization fixing layer that will become the magnetization fixing layer 52, a buffer layer 51, a spacer layer 53, a free layer 54, and a capping layer 55.

[0112] Next, using a laser and an external magnetic field containing a component in a specified direction, the magnetization direction of the initial magnetization fixing layer is fixed to the above-mentioned specified direction. For example, in a plurality of initial MR elements that will become a plurality of MR elements 50A constituting the resistance portions R11 and R13 of the first detection circuit 10, while applying an external magnetic field in the X direction, the plurality of initial MR elements are irradiated with a laser. When the irradiation of the laser is completed, the magnetization direction of the initial magnetization fixing layer is fixed to the X direction. Thus, the initial magnetization fixing layer becomes the magnetization fixing layer 52, and the initial MR element becomes the MR element 50A.

[0113] In addition, among a plurality of initial MR elements of the MR elements 50A that later become the resistance portions R12 and R14 constituting the first detection circuit 10, by using an external magnetic field in the -X direction, the magnetization directions of the initial magnetization fixing layers of the plurality of initial MR elements can be fixed in the -X direction. In this way, the plurality of MR elements 50A are formed. The plurality of MR elements 50B of each of the resistance portions R21 to R24 constituting the second detection circuit 20 are also formed by the same method as the plurality of MR elements 50A.

[0114] Next, the process of fixing the magnetization direction of the ferromagnetic layer 72 will be described. The magnetization direction of the ferromagnetic layer 72 is fixed by the same method as the magnetization fixing layer 52 of the MR element 50. That is, first, as described with reference to ​ and ​ , after forming the antiferromagnetic layer 74 and the covering layer 75, the magnetization direction of the ferromagnetic layer 72 is fixed to the above-mentioned specified direction by using a laser and an external magnetic field containing a component in a specified direction. For example, for a plurality of ferromagnetic layers 72 respectively disposed near the plurality of MR elements 50A that later constitute the resistance portions R11 and R12 of the first detection circuit 10, while applying an external magnetic field in the Y direction, the plurality of ferromagnetic layers 72 are irradiated with a laser. When the irradiation of the laser is completed, the magnetization direction of the ferromagnetic layer 72 is fixed in the Y direction.

[0115] In addition, for a plurality of ferromagnetic layers 72 respectively disposed near the plurality of MR elements 50A that later constitute the resistance portions R13 and R14 of the first detection circuit 10, the magnetization directions of the plurality of ferromagnetic layers 72 can be fixed in the -Y direction by using an external magnetic field in the -Y direction. The magnetization directions of the plurality of ferromagnetic layers 72 respectively disposed near the plurality of MR elements 50B of each of the resistance portions R21 to R24 constituting the second detection circuit 20 are also fixed by the same method as described above.

[0116] In addition, the intensity of the laser for fixing the magnetization direction of the ferromagnetic layer 72 may be smaller than the intensity of the laser for fixing the magnetization direction of the magnetization fixing layer 52. In addition, the intensity of the laser for fixing the magnetization direction of the ferromagnetic layer 72 is preferably an intensity that suppresses the change in the ratio of the magnetoresistance change to the resistance of the MR element 50, that is, the magnetoresistance change rate.

[0117] [Modification Example]

[0118] Next, the first to seventh modification examples of the magnetic sensor 1 of the present embodiment will be described. First, the first modification example will be described with reference to ​ as follows. ​It is a top view showing the main part of the first modification of the magnetic sensor 1. In the first modification, a plurality of lower electrodes 61 electrically connect two MR elements 50 adjacent to each other in the first direction D1. A plurality of upper electrodes 62 are respectively disposed above the two lower electrodes 61 and electrically connect the adjacent two MR elements 50. Thus, a plurality of MR elements 50 arranged in a line in the first direction D1 are connected in series. In the first modification, a plurality of connection electrodes electrically connect the plurality of lower electrodes 61 or the plurality of upper electrodes 62 in such a manner as to connect in series a group of a plurality of MR elements 50 arranged in a line.

[0119] In addition, in the first modification, a second laminate 702 is interposed between two MR elements 50 arranged along the first direction D1 and the upper electrode 62. The two MR elements 50 are also electrically connected through the antiferromagnetic layer 74 (see ​ and ​ ) of the second laminate 702. In addition, the two MR elements 50 are also connected in series through the antiferromagnetic layer 74.

[0120] Next, the second modification will be described with reference to ​ FIG. ​ It is a top view showing the main part of the second modification of the magnetic sensor 1. In the second modification, two MR elements 50 and three magnetic field generators 70 are disposed between the lower electrode 61 and the upper electrode 62. Here, in order to distinguish the three magnetic field generators 70 from each other, "first", "second" and "third" are used. The first magnetic field generator 70 is disposed between two MR elements 50 arranged along the first direction D1. The second magnetic field generator 70 is disposed at a position sandwiching one of the two MR elements 50 between the second magnetic field generator 70. The third magnetic field generator 70 is disposed at a position sandwiching the other of the two MR elements 50 between the first magnetic field generator 70.

[0121] ​ The two MR elements 50 shown in FIG. may also be connected to the same lower electrode 61 and the same upper electrode 62. The two MR elements 50 may also be connected in parallel in the circuit structure. Here, the two MR elements 50 connected in parallel in the circuit structure are referred to as an element pair. Each of the plurality of lower electrodes 61 electrically connects two element pairs adjacent to each other in the second direction D2. Each of the plurality of upper electrodes 62 is disposed above the two lower electrodes 61 and electrically connects the adjacent two element pairs. Thus, a plurality of element pairs arranged in a line in the second direction D2 are connected in series.

[0122] A second laminate 702 is interposed between two element pairs and an upper electrode 62 that electrically connects the two element pairs. In the second modification, the second laminate 702 is disposed above the four MR elements 50 and the six first laminates 701. In the second modification, the second laminate 702 includes six laminated portions 702a.

[0123] Next, ​ a third modification will be described. ​ FIG. is a plan view showing a main part of a third modification of the magnetic sensor 1. In the third modification, two MR elements 50 arranged along the second direction D2 are disposed between two magnetic field generating bodies 70 arranged along the first direction D1.

[0124] ​ The two MR elements 50 shown are connected to the same lower electrode 61 and the same upper electrode 62. The two MR elements 50 are a pair of elements connected in parallel in a circuit configuration. Each of the plurality of lower electrodes 61 electrically connects two element pairs adjacent in the second direction D2. Each of the plurality of upper electrodes 62 is disposed above two lower electrodes 61 and electrically connects adjacent two element pairs. Thus, a plurality of element pairs arranged in a line in the second direction D2 are connected in series.

[0125] A second laminate 702 is interposed between two element pairs and an upper electrode 62 that electrically connects the two element pairs. In the third modification, the second laminate 702 is disposed above the four MR elements 50 and the four first laminates 701. In the third modification, the second laminate 702 includes four laminated portions 702a.

[0126] Next, ​ a fourth modification will be described. ​ FIG. is a cross-sectional view showing a main part of a fourth modification of the magnetic sensor 1. In the fourth modification, the first laminate 701 includes an antiferromagnetic layer 76 disposed between the buffer layer 71 and the ferromagnetic layer 72 in addition to the buffer layer 71 and the ferromagnetic layer 72. The antiferromagnetic layer 76 is formed of an antiferromagnetic material such as IrMn or PtMn, for example.

[0127] The antiferromagnetic layer 76 is in contact with the lower surface of the ferromagnetic layer 72 and exchange-couples with the ferromagnetic layer 72. In addition, as described above, the antiferromagnetic portion 74a exchange-couples with the ferromagnetic layer 72. In the fourth modification, the magnetization direction of the ferromagnetic layer 72 is defined by the exchange-coupling of the antiferromagnetic portion 74a and the antiferromagnetic layer 76 with the ferromagnetic layer 72.

[0128] Next, ​ a fifth modification will be described. ​It is a cross-sectional view showing the main part of the fifth modification example of the magnetic sensor 1. In the fifth modification example, the first laminate 701 includes, in addition to the buffer layer 71 and the ferromagnetic layer 72, a ferromagnetic layer 77 disposed between the buffer layer 71 and the ferromagnetic layer 72. The ferromagnetic layer 77 is formed of a ferromagnetic material containing one or more elements of Co, Fe, and Ni. In the fifth modification example, the ferromagnetic layer 77 has magnetization in the same direction as the magnetization of the ferromagnetic layer 72.

[0129] In the fifth modification example, the ferromagnetic layer 72 may be formed of a ferromagnetic material capable of increasing the exchange coupling energy with the antiferromagnetic portion 74a, and the ferromagnetic layer 77 may be formed of a ferromagnetic material having a saturation magnetic flux density larger than that of the ferromagnetic material constituting the ferromagnetic layer 72. In this case, it is possible to increase the exchange coupling energy between the ferromagnetic body portion composed of the ferromagnetic layers 72 and 77 and the antiferromagnetic portion 74a, increase the intensity of the bias magnetic field generated by the magnetic field generating body 70, and miniaturize the magnetic field generating body 70. As an example of the ferromagnetic layer 72, a Co 70 Fe 30 layer can be cited. As an example of the ferromagnetic layer 77, a Co 30 Fe 70 layer can be cited.

[0130] Next, refer to ​ to describe the sixth modification example. ​ It is a cross-sectional view showing the main part of the sixth modification example of the magnetic sensor 1. In the sixth modification example, the first laminate 701 includes, in addition to the buffer layer 71 and the ferromagnetic layer 72, a ferromagnetic layer 78 disposed between the buffer layer 71 and the ferromagnetic layer 72, and a nonmagnetic layer 79 disposed between the ferromagnetic layer 72 and the ferromagnetic layer 78. The ferromagnetic layer 78 is formed of a ferromagnetic material containing one or more elements of Co, Fe, and Ni. The ferromagnetic layer 72 and the ferromagnetic layer 78 may be formed of the same ferromagnetic material or different ferromagnetic materials. The nonmagnetic layer 79 is formed of a nonmagnetic metal material such as Ru, for example.

[0131] In the sixth modification example, the ferromagnetic layer 72 and the ferromagnetic layer 78 are ferromagnetically exchange-coupled via the nonmagnetic layer 79 in such a manner that their magnetization directions are the same. The ferromagnetic layer 72 and the ferromagnetic layer 78 have magnetization in the same direction. The thickness of the nonmagnetic layer 79 is set to a thickness such that the exchange coupling between the ferromagnetic layer 72 and the ferromagnetic layer 78 does not disappear.

[0132] Next, refer to ​ to describe the seventh modification example. In the seventh modification example, the two side surfaces 50c of the MR element 50 are formed by referring to ​In the step of patterning the described laminated film, it is formed by etching at least the gap layer 53, the free layer 54, and the covering layer 55. In this step, a part of the magnetization fixing layer 52 may or may not be etched.

[0133] In the seventh modification, the ferromagnetic layer 72 is arranged to rise above the side surface 50c of the MR element 50 and the magnetization fixing layer 52. The insulating layer 33 is formed along the side surface 50c of the MR element 50 and the upper surface of the magnetization fixing layer 52.

[0134] In addition, the first to seventh modifications can be arbitrarily combined. For example, it is also possible to combine ​ the first modification shown in ​ with the second modification shown in ​ or the third modification shown in

[0135] [Second Embodiment]

[0136] Next, a second embodiment of the present invention will be described. First, with reference to ​ the structure of a magnetic sensor system including the magnetic sensor of this embodiment will be described. ​ is a perspective view showing the magnetic sensor system 200 in this embodiment.

[0137] The magnetic sensor system 200 includes the magnetic sensor 201 of this embodiment and a magnetic field generation unit 202 that generates a prescribed magnetic field. In this embodiment, the magnetic field generation unit 202 is a magnet configured to apply a part of the generated magnetic field, i.e., a partial magnetic field, to the magnetic sensor 201. This partial magnetic field includes a first magnetic field component Hz parallel to the Z direction and a second magnetic field component Hy parallel to the Y direction.

[0138] As shown in ​ in this embodiment, the magnetization direction of the magnetic field generation unit 202 is the Y direction, and the direction of the second magnetic field component Hy is the -Y direction. When the magnetic field generation unit 202 moves in the Y direction from a prescribed position, the direction of the first magnetic field component Hz becomes the Z direction, and when the magnetic field generation unit 202 moves in the -Y direction from the prescribed position, the direction of the first magnetic field component Hz becomes the -Z direction.

[0139] Next, with reference to ​ the schematic structure of the magnetic sensor 201 of this embodiment will be described. ​ is a circuit diagram showing the circuit structure of the magnetic sensor 201.

[0140] The magnetic sensor 201 includes four resistance portions R31, R32, R33, R34, a power supply port V3, a ground port G3, and two output ports E31, E32. The resistance portion R31 is disposed between the power supply port V3 and the output port E31. The resistance portion R32 is disposed between the output port E31 and the ground port G3. The resistance portion R33 is disposed between the output port E32 and the ground port G3. The resistance portion R34 is disposed between the power supply port V3 and the output port E32. A voltage or current of a specified magnitude is applied to the power supply port V3. The ground port G3 is grounded.

[0141] The resistance portions R31 to R34 each include a plurality of MR elements 50. The structure of the plurality of MR elements 50 is the same as that of the first embodiment. That is, as in the first embodiment ​ and ​ shown, the plurality of MR elements 50 each include a buffer layer 51, a magnetization fixing layer 52, a spacer layer 53, a free layer 54, and a cover layer 55.

[0142] In ​ , a plurality of solid arrows depicted so as to overlap the resistance portions R31 to R34 respectively indicate the magnetization directions of the magnetization fixing layers 52 in the respective resistance portions R31 to R34. In the example shown in ​ , the directions of the main components of the magnetization of the magnetization fixing layers 52 in the resistance portions R31 and R34 are the X direction. The directions of the main components of the magnetization of the magnetization fixing layers 52 in the resistance portions R32 and R33 are the -X direction. The free layers 54 in the resistance portions R31 to R34 each have shape anisotropy such that the direction of the easy magnetization axis is parallel to the Y direction.

[0143] The resistance portions R31 to R34 each further include a plurality of magnetic field generators 70. The structure of the plurality of magnetic field generators 70 is the same as that of the first embodiment. The plurality of magnetic field generators 70 include pairs of a plurality of magnetic field generators 70 each composed of two magnetic field generators 70. The above two magnetic field generators 70 are arranged at intervals in a direction parallel to the Y direction with one MR element 50 sandwiched therebetween. The two magnetic field generators 70 are configured to apply a bias magnetic field to one MR element 50 located therebetween. The bias magnetic field includes a component in the direction parallel to the Y direction as the main component.

[0144] In ​ , arrows labeled with symbols M31, M32, M33, M and M34 respectively indicate the directions of the main components of the bias magnetic fields generated by the plurality of magnetic field generators 70 in the resistance portions R31, R32, R33, and R34. The directions of the main components of the bias magnetic fields in the resistance portions R31 and R34 are the Y direction. The directions of the main components of the bias magnetic fields in the resistance portions R32 and R33 are the -Y direction.

[0145] In​ In ​ , a plurality of hollow arrows depicted so as to overlap with the resistance units R31 to R34 respectively indicate the magnetization directions of the free layers in each of the resistance units R31 to R34 when a partial magnetic field is not applied to the magnetic sensor 201. The directions of the main components of the magnetization of the free layers in each of the resistance units R31 and R34 are in the Y direction, which is the same as the direction of the main component of the bias magnetic field in the resistance units R31 and R34. The directions of the main components of the magnetization of the free layers in each of the resistance units R32 and R33 are in the -Y direction, which is the same as the direction of the main component of the bias magnetic field in the resistance units R32 and R33.

[0146] Next, with reference to ​ the structure of the magnetic sensor 201 will be specifically described. ​ FIG. ​ is a perspective view showing a part of the magnetic sensor 201. ​ FIG. ​ is a top view showing a part of the magnetic sensor 201. ​ FIG. ​ is a side view showing a part of the magnetic sensor 201.

[0147] The magnetic sensor 201 further includes a substrate 230. The magnetic sensor 201 is formed by forming a plurality of components other than the substrate 230 on the substrate 230.

[0148] The magnetic sensor 201 further includes at least one magnetic yoke made of a soft magnetic material. When viewed from the Z direction, the at least one magnetic yoke has a shape that is longer in the Y direction. In addition, the at least one magnetic yoke generates a magnetic field component in a direction parallel to the X direction based on ​ the first magnetic field component Hz shown in ​ .

[0149] As shown in ​ in the present embodiment, in particular, the magnetic sensor 201 includes a plurality of magnetic yokes 250 arranged along the X direction as the at least one magnetic yoke. The plurality of magnetic yokes 250 each have, for example, a rectangular parallelepiped shape that is longer in the Y direction. The plurality of magnetic yokes 250 have the same shape. The plurality of magnetic yokes 250 each have a first end face 250a and a second end face 250b located at both ends in a direction parallel to the X direction. In each of the plurality of magnetic yokes 250, the first end face 250a is located at one end in the -X direction, and the second end face 250b is located at one end in the X direction.

[0150] A plurality of MR elements 50 are respectively arranged at positions where the magnetic field components generated by a plurality of magnetic yokes 250 are applied. In the present embodiment, in particular, the MR elements 50 are respectively arranged near the -Z direction ends of the plurality of magnetic yokes 250. Further, the plurality of MR elements 50 are arranged such that a plurality of them are arranged along each of the first end face 250a or the second end face 250b of the plurality of magnetic yokes 250. Hereinafter, a plurality of MR elements 50 arranged along the first end face 250a among the plurality of MR elements 50 are denoted by the symbol 50C, and a plurality of MR elements 50 arranged along the second end face 250b are denoted by the symbol 50D. The directions of the magnetic field components received by the plurality of MR elements 50C and the directions of the magnetic field components received by the plurality of MR elements 50D are opposite to each other.

[0151] When viewed from the Z direction, the plurality of MR elements 50C and the plurality of MR elements 50D may overlap with the plurality of magnetic yokes 250 or may not overlap with the plurality of magnetic yokes 250. In ​ The example shown, when viewed from the Z direction, the plurality of MR elements 50C and the plurality of MR elements 50D are arranged so as not to overlap with the plurality of magnetic yokes 250.

[0152] As ​ and ​ shown, a plurality of magnetic field generators 70 configured to sandwich the MR element 50C among the plurality of magnetic field generators 70 are denoted by the symbol 70C, and a plurality of magnetic field generators 70 configured to sandwich the MR element 50D are denoted by the symbol 70D. The magnetic sensor 201 further includes a plurality of magnetic yokes 90C and a plurality of magnetic yokes 90D each including a magnetic layer made of a soft magnetic material. The plurality of magnetic yokes 90C include pairs of the plurality of magnetic yokes 90C each composed of two magnetic yokes 90C. The above two magnetic yokes 90C are arranged on both sides of one MR element 50C in a direction parallel to the X direction. The plurality of magnetic yokes 90D include pairs of the plurality of magnetic yokes 90D each composed of two magnetic yokes 90D. The above two magnetic yokes 90D are arranged on both sides of one MR element 50D in a direction parallel to the X direction.

[0153] The plurality of magnetic yokes 90C have a function of guiding the magnetic field components generated by the plurality of magnetic yokes 250 to the plurality of MR elements 50C. The plurality of magnetic yokes 90D have a function of guiding the magnetic field components generated by the plurality of magnetic yokes 250 to the plurality of MR elements 50D.

[0154] The magnetic sensor 201 further includes a wiring portion 211 that electrically connects the plurality of MR elements 50C and a wiring portion 212 that electrically connects the plurality of MR elements 50D. The wiring portions 211 and 212 are each composed of a plurality of lower electrodes 61, a plurality of upper electrodes 62, and a plurality of connection electrodes. Further, the lower electrode 61 and the upper electrode 62 are shown in ​ described later.

[0155] The wiring section 211 includes: a first wiring that electrically connects a plurality of MR elements 50C in which the direction of the main component of the magnetization of the magnetization fixing layer 52 is in the X direction; and a second wiring that electrically connects a plurality of MR elements 50C in which the direction of the main component of the magnetization of the magnetization fixing layer 52 is in the -X direction. The resistance section R31 is composed of a plurality of MR elements 50C electrically connected by the first wiring. The resistance section R32 is composed of a plurality of MR elements 50C electrically connected by the second wiring.

[0156] The wiring section 212 includes: a third wiring that electrically connects a plurality of MR elements 50D in which the direction of the main component of the magnetization of each magnetization fixing layer 52 is in the -X direction; and a fourth wiring that electrically connects a plurality of MR elements 50D in which the direction of the main component of the magnetization of each magnetization fixing layer 52 is in the X direction. The resistance section R33 is composed of a plurality of MR elements 50D electrically connected by the third wiring. The resistance section R34 is composed of a plurality of MR elements 50D electrically connected by the fourth wiring.

[0157] Next, the operation of the magnetic sensor 201 will be described. As a result of the absence of the first magnetic field component Hz, and thus in a state where the magnetic field components generated by the plurality of magnetic yokes 250 are also absent, the magnetization directions of the free layers 54 of the plurality of MR elements 50C and the plurality of MR elements 50D each become a direction parallel to the Y direction.

[0158] When the direction of the first magnetic field component Hz is in the Z direction, the direction of the magnetic field component received by each of the plurality of MR elements 50C constituting the resistance sections R31 and R32 becomes the X direction, and the direction of the magnetic field component received by each of the plurality of MR elements 50D constituting the resistance sections R33 and R34 becomes the -X direction. In this case, the magnetization directions of the free layers 54 of the plurality of MR elements 50C each tilt from the direction parallel to the Y direction toward the X direction, and the magnetization directions of the free layers 54 of the plurality of MR elements 50D each tilt from the direction parallel to the Y direction toward the -X direction. As a result, compared with the state where the magnetic field component is absent, the resistance values of the plurality of MR elements 50C constituting the resistance section R31 and the resistance values of the plurality of MR elements 50D constituting the resistance section R33 decrease, and the resistance values of the plurality of MR elements 50C constituting the resistance section R32 and the resistance values of the plurality of MR elements 50D constituting the resistance section R34 increase. As a result, the resistance values of the resistance sections R31 and R33 decrease, and the resistance values of the resistance sections R32 and R34 increase.

[0159] In the case where the direction of the first magnetic field component Hz is in the -Z direction, the direction of the magnetic field component and the change in the resistance value of each of the resistance sections R31 to R34 are opposite to those in the case where the direction of the first magnetic field component Hz is in the Z direction described above.

[0160] The change amounts of the resistance values of the resistance portions R31 to R34 respectively depend on the intensities of the magnetic field components received by the plurality of MR elements 50C and the plurality of MR elements 50D. When the intensity of the magnetic field component becomes larger, the resistance values of the resistance portions R31 to R34 respectively change in the direction in which their increase amounts or decrease amounts become larger. When the intensity of the magnetic field component becomes smaller, the resistance values of the resistance portions R31 to R34 respectively change in the direction in which their increase amounts or decrease amounts become smaller. The intensity of the magnetic field component depends on the intensity of the first magnetic field component Hz.

[0161] Thus, when the direction and intensity of the first magnetic field component Hz change, the resistance values of the resistance portions R31 to R34 respectively change in such a manner that the resistance values of the resistance portions R31 and R33 increase and the resistance values of the resistance portions R32 and R34 decrease, or the resistance values of the resistance portions R31 and R33 decrease and the resistance values of the resistance portions R32 and R34 increase. Thereby, the potential of the connection point of the resistance portions R31 and R32, that is, the potential of the output port E31, and the potential of the connection point of the resistance portions R33 and R3, that is, the potential of the output port E32, change. The magnetic sensor 201 can also generate a signal corresponding to the potential of the output port E31 and a signal corresponding to the potential of the output port E32 as detection signals respectively. Alternatively, the magnetic sensor 201 can also generate a signal corresponding to the potential difference between the output ports E31 and E32 as a detection signal. In this case, the magnetic sensor 201 can also further include a differential amplifier (differential detector) that outputs a signal corresponding to the potential difference between the output ports E31 and E32 as a detection signal.

[0162] The magnetic sensor system 200 can also further include the ​ and ​ processor 2 shown in the first embodiment. The processor 2 can also be configured to receive one detection signal or two detection signals output from the magnetic sensor 201, and generate a detection value corresponding to the intensity of the first magnetic field component Hz or a detection value corresponding to the position of the magnetic field generation unit 202 (refer to ​ ).

[0163] Next, the plurality of magnetic yokes 90C and the plurality of magnetic yokes 90D will be described in detail with reference to ​ . ​ is a top view showing the main part of the magnetic sensor 201. ​ is showing ​ a partial cross-sectional view of the position indicated by the line 26-26 in ​ is showing ​ a partial cross-sectional view of the position indicated by the line 27-27 in

[0164] Hereinafter, any one of the plurality of magnetic yokes 90C and 90D is represented by the symbol 90. The structures and shapes of the MR element 50 and the magnetic field generator 70, and the positional relationship between the MR element 50 and the magnetic field generator 70 are the same as those in the first embodiment. In addition, the structures and shapes of the first and second stacked bodies 701 and 702, and the positional relationship between the MR element 50 and the first and second stacked bodies 701 and 702 are also the same as those in the first embodiment.

[0165] Here, focusing on one MR element 50, the structure of the magnetic yoke 90 will be described. The two magnetic yokes 90 are arranged on both sides of the MR element 50 in a direction parallel to the X direction. The magnetic sensor 201 further includes an insulating layer 232 made of an insulating material such as Al2O3 or SiO2. The insulating layer 232 is arranged on both sides of the MR element 50 in a direction parallel to the X direction. In the present embodiment, in particular, the insulating layer 232 is arranged around the MR element 50 and the ferromagnetic layer 72 of the magnetic field generator 70.

[0166] The two magnetic yokes 90 are embedded in the insulating layer 232. An insulating layer 232 is interposed between the MR element 50 and the two magnetic yokes 90, and between the lower electrode 61 and the two magnetic yokes 90. Each of the two magnetic yokes 90 may further include a buffer layer interposed between the magnetic layer and the insulating layer 232, and a covering layer arranged above the magnetic layer, in addition to the magnetic layer. The buffer layer and the covering layer may be formed of a non-magnetic metal material, for example. In addition, the two magnetic yokes 90 are respectively arranged to rise to the side surface 50d of the MR element 50. When viewed from the Z direction, a part of each of the two magnetic yokes 90 overlaps with a part of the MR element 50.

[0167] The two magnetic yokes 90 are arranged between two magnetic field generators 70 arranged at intervals in a direction parallel to the Y direction. The ferromagnetic layer 72 of the magnetic field generator 70 (the first stacked body 701) is arranged to overlap the two magnetic yokes 90 when viewed from the Y direction or the -Y direction.

[0168] The ferromagnetic layer 72 is arranged to rise to the magnetic yoke 90. When viewed from the Z direction, a part of the ferromagnetic layer 72 overlaps with a part of the magnetic yoke 90. The magnetic sensor 201 further includes an insulating layer 233 made of an insulating material such as Al2O3 or SiO2 and interposed between the ferromagnetic layer 72 and the magnetic yoke 90. A part of the buffer layer 71 of the magnetic field generator 70 (the first stacked body 701) is interposed between the ferromagnetic layer 72 and the insulating layer 233.

[0169] In this embodiment, the antiferromagnetic layer 74 is disposed over the MR element 50, the two ferromagnetic layers 72, the two yokes 90, and the insulating layer 232. The upper surfaces of the two yokes 90 may also be in contact with the antiferromagnetic layer 74. The magnetic sensor 201 further includes: an insulating layer 231 made of an insulating material such as Al2O3 or SiO2 and interposed between the substrate 230 (refer to ​ ) and the lower electrode 61; and an insulating layer (not shown) made of an insulating material and disposed over the upper electrode 62.

[0170] Other structures, operations, and effects in this embodiment are the same as those in the first embodiment.

[0171] [Third Embodiment]

[0172] Next, refer to ​ to describe the third embodiment of the present invention. ​ is a top view showing the main part of the magnetic sensor of this embodiment. ​ is showing ​ a partial cross-sectional view of the position indicated by line 29-29 in ​ is showing ​ a partial cross-sectional view of the position indicated by line 30-30 in

[0173] Hereinafter, focusing on one MR element 50, the differences in the structure of the magnetic sensor 201 of this embodiment from the second embodiment will be described. In this embodiment, the two magnetic field generators 70 are respectively disposed at intervals with respect to the MR element 50. Therefore, the ferromagnetic layers 72 of the two magnetic field generators 70 are disposed at intervals with respect to the MR element 50.

[0174] In addition, the two magnetic field generators 70 are respectively disposed at intervals from the two yokes 90. Therefore, the ferromagnetic layers 72 of the two magnetic field generators 70 are disposed at intervals from the two yokes 90.

[0175] In this embodiment, an insulating layer 233 is interposed between the ferromagnetic layer 72 and the lower electrode 61 and the insulating layer 232. The magnetic sensor 201 further includes an insulating layer 234 made of an insulating material such as Al2O3 or SiO2 and interposed between the two yokes 90 and the lower electrode 61 and the insulating layer 232.

[0176] Other structures, operations, and effects in this embodiment are the same as those in the second embodiment.

[0177] In addition, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, the magnetic sensor of the present invention may also be a magnetic sensor including the first and second detection circuits 10 and 20 in the first embodiment, and the magnetic sensor 201 of the second embodiment as the third detection circuit. In this magnetic sensor, the third detection circuit (magnetic sensor 201) may also be configured to detect a component in the direction parallel to the Z direction of the magnetic field to be detected. This magnetic sensor may also be a geomagnetic sensor using the target magnetic field as the geomagnetism.

[0178] In addition, the MR element 50 may also be formed by laminating a buffer layer 51, a free layer 54, a gap layer 53, a magnetization fixing layer 52, and a cover layer 55 in this order from the lower electrode 61 side.

[0179] As described above, the magnetic sensor of the present invention includes: at least one magnetoresistive effect element including a plurality of stacked magnetic films; a first ferromagnetic layer made of a ferromagnetic material and disposed to overlap at least one magnetoresistive effect element when viewed in a first direction orthogonal to the stacking direction of the plurality of magnetic films; an insulating layer made of an insulating material and disposed on both sides of at least one magnetoresistive effect element in a second direction orthogonal to the stacking direction and the first direction, respectively; and an antiferromagnetic layer disposed above at least one magnetoresistive effect element, the first ferromagnetic layer, and the insulating layer. The antiferromagnetic layer includes a first antiferromagnetic portion facing the first ferromagnetic layer and a non-facing portion facing at least one magnetoresistive effect element and the insulating layer but not facing the first ferromagnetic layer. There is no magnetic layer between at least one magnetoresistive effect element and the antiferromagnetic layer.

[0180] In the magnetic sensor of the present invention, the first ferromagnetic layer and the first antiferromagnetic portion may also constitute a magnetic field generating body that generates a magnetic field applied to at least one magnetoresistive effect element.

[0181] In addition, in the magnetic sensor of the present invention, at least one magnetoresistive effect element may also be a first magnetoresistive effect element and a second magnetoresistive effect element. The first magnetoresistive effect element and the second magnetoresistive effect element may be connected in series via an antiferromagnetic layer. The first magnetoresistive effect element and the second magnetoresistive effect element may be arranged along the first direction. Alternatively, the first magnetoresistive effect element and the second magnetoresistive effect element may be arranged along the second direction.

[0182] In addition, the magnetic sensor of the present invention may further include: a second ferromagnetic layer, which is made of a ferromagnetic material and is disposed at a position sandwiching at least one magnetoresistive element between the first ferromagnetic layer in a first direction. The antiferromagnetic layer may further include a second antiferromagnetic portion facing the second ferromagnetic layer. The first ferromagnetic layer and the first antiferromagnetic portion may form a first magnetic field generating body that generates a first magnetic field applied to at least one magnetoresistive element. The second ferromagnetic layer and the second antiferromagnetic portion may form a second magnetic field generating body that generates a second magnetic field applied to at least one magnetoresistive element. At least one magnetoresistive element may be a first magnetoresistive element and a second magnetoresistive element. The first magnetoresistive element and the second magnetoresistive element may be connected in parallel in a circuit structure.

[0183] In addition, in the magnetic sensor of the present invention, the antiferromagnetic layer may be in contact with at least one magnetoresistive element. At least one magnetoresistive element may further include: a nonmagnetic metal layer, which is interposed between the antiferromagnetic layer and a plurality of magnetic films and is in contact with the antiferromagnetic layer.

[0184] In addition, in the magnetic sensor of the present invention, the plurality of magnetic films may include: a free layer, which has magnetization whose direction can vary according to an object magnetic field. The first ferromagnetic layer may have a side surface facing at least one magnetoresistive element. The side surface may include an inclined portion facing the free layer and inclined with respect to the stacking direction. The angle formed by the inclined portion and the stacking direction may be in the range of 20° or more and 90° or less.

[0185] In addition, in the magnetic sensor of the present invention, at least one magnetoresistive element may have a first surface facing a non-opposing portion and a second surface on the opposite side of the first surface. The interval between at least a part of the non-opposing portion and the second surface may be the same as the interval between the first surface and the second surface.

[0186] In addition, the magnetic sensor of the present invention may further include: two magnetic yokes, which are disposed on both sides of at least one magnetoresistive element in a second direction and are each made of a soft magnetic material. The antiferromagnetic layer may be disposed on at least one magnetoresistive element, the first ferromagnetic layer, the insulating layer, and the two magnetic yokes.

[0187] In addition, the magnetic sensor of the present invention may further include: a first port; a second port; a third port; a first resistor section disposed between the first port and the second port in a circuit structure; and a second resistor section disposed between the second port and the third port in a circuit structure. Each of the first resistor section and the second resistor section may include at least one magnetoresistive element, a first ferromagnetic layer, an insulating layer, and an antiferromagnetic layer. The plurality of magnetic films may also include: a free layer having magnetization whose direction can vary according to an object magnetic field. In the first resistor section, the first ferromagnetic layer and the first antiferromagnetic section may constitute a first magnetic field generating body that generates a first magnetic field applied to at least one magnetoresistive element. In the second resistor section, the first ferromagnetic layer and the first antiferromagnetic section may constitute a second magnetic field generating body that generates a second magnetic field applied to at least one magnetoresistive element. The first magnetic field may include, as a main component, a component in a first magnetic field direction, which is a direction parallel to a first direction. The second magnetic field may include, as a main component, a component in a second magnetic field direction, which is a direction opposite to the first magnetic field direction. In the first resistor section, in the case where no object magnetic field is applied to the magnetic sensor, the magnetization of the free layer may include a component in the first magnetic field direction. In the second resistor section, in the case where no object magnetic field is applied to the magnetic sensor, the magnetization of the free layer may include a component in the second magnetic field direction.

[0188] Based on the above description, various embodiments and modifications of the present invention can be implemented. Therefore, within the equivalent scope of the claims, the present invention can be implemented even for embodiments other than the above-described best embodiment.

Claims

1. A magnetic sensor, characterized in that: It includes: At least one magnetoresistive element, which includes a plurality of stacked magnetic films; A first ferromagnetic layer, which is made of a ferromagnetic material and is configured to overlap with the at least one magnetoresistive element when viewed from a first direction orthogonal to the stacking direction of the plurality of magnetic films; An insulating layer, which is made of an insulating material and is disposed on both sides of the at least one magnetoresistive element in a second direction orthogonal to the stacking direction and the first direction respectively; And An antiferromagnetic layer, which is disposed above the at least one magnetoresistive element, the first ferromagnetic layer and the insulating layer, The antiferromagnetic layer includes: a first antiferromagnetic portion opposite to the first ferromagnetic layer, and a non-opposite portion opposite to the at least one magnetoresistive element and the insulating layer but not opposite to the first ferromagnetic layer, There is no magnetic layer between the at least one magnetoresistive element and the antiferromagnetic layer.

2. The magnetic sensor according to claim 1, characterized in that: The first ferromagnetic layer and the first antiferromagnetic portion constitute a magnetic field generating body that generates a magnetic field applied to the at least one magnetoresistive element.

3. The magnetic sensor according to claim 1, characterized in that: The at least one magnetoresistive element is a first magnetoresistive element and a second magnetoresistive element, The first magnetoresistive element and the second magnetoresistive element are connected in series via the antiferromagnetic layer.

4. The magnetic sensor according to claim 3, characterized in that: The first magnetoresistive element and the second magnetoresistive element are arranged along the first direction.

5. The magnetic sensor according to claim 3, characterized in that: The first magnetoresistive element and the second magnetoresistive element are arranged along the second direction.

6. The magnetic sensor according to claim 1, characterized in that: It further includes: a second ferromagnetic layer, which is made of a ferromagnetic material and is disposed at a position where the at least one magnetoresistive element is sandwiched between the first ferromagnetic layer in the first direction, The antiferromagnetic layer further includes a second antiferromagnetic portion opposite to the second ferromagnetic layer, The first ferromagnetic layer and the first antiferromagnetic portion constitute a first magnetic field generating body that generates a first magnetic field applied to the at least one magnetoresistive element, The second ferromagnetic layer and the second antiferromagnetic portion constitute a second magnetic field generating body that generates a second magnetic field applied to the at least one magnetoresistive element.

7. The magnetic sensor according to claim 6, characterized in that: The at least one magnetoresistive element is a first magnetoresistive element and a second magnetoresistive element, The first magnetoresistive element and the second magnetoresistive element are connected in parallel in the circuit structure.

8. The magnetic sensor according to claim 1, characterized in that: The antiferromagnetic layer is in contact with the at least one magnetoresistive element.

9. The magnetic sensor according to claim 8, characterized in that: The at least one magnetoresistive effect element further includes: a nonmagnetic metal layer interposed between the antiferromagnetic layer and the plurality of magnetic films and in contact with the antiferromagnetic layer.

10. The magnetic sensor according to claim 1, wherein the plurality of magnetic films includes: a free layer having magnetization whose direction can vary according to an object magnetic field, the first ferromagnetic layer has a side surface opposite to the at least one magnetoresistive effect element, the side surface includes an inclined portion opposite to the free layer and inclined with respect to the stacking direction, an angle formed by the inclined portion and the stacking direction is in a range of 20° or more and 90° or less.

11. The magnetic sensor according to claim 1, wherein the at least one magnetoresistive effect element has a first surface opposite to the non-opposite portion and a second surface on a side opposite to the first surface, a distance between at least a part of the non-opposite portion and the second surface is the same as a distance between the first surface and the second surface.

12. The magnetic sensor according to claim 1, wherein further includes: two magnetic yokes disposed on both sides of the at least one magnetoresistive effect element in the second direction and each made of a soft magnetic material, the antiferromagnetic layer is disposed above the at least one magnetoresistive effect element, the first ferromagnetic layer, the insulating layer, and the two magnetic yokes.

13. The magnetic sensor according to claim 1, wherein further includes: a first port; a second port; a third port; a first resistor portion configured between the first port and the second port in a circuit structure; and a second resistor portion configured between the second port and the third port in a circuit structure, the first resistor portion and the second resistor portion each include the at least one magnetoresistive effect element, the first ferromagnetic layer, the insulating layer, and the antiferromagnetic layer, the plurality of magnetic films includes: a free layer having magnetization whose direction can vary according to an object magnetic field, in the first resistor portion, the first ferromagnetic layer and the first antiferromagnetic portion constitute a first magnetic field generating body that generates a first magnetic field applied to the at least one magnetoresistive effect element, in the second resistor portion, the first ferromagnetic layer and the first antiferromagnetic portion constitute a second magnetic field generating body that generates a second magnetic field applied to the at least one magnetoresistive effect element, the first magnetic field includes a component in a first magnetic field direction as a main component, and the first magnetic field direction is a direction parallel to the first direction, the second magnetic field includes a component in a second magnetic field direction opposite to the first magnetic field direction as a main component, in the first resistor portion, in a case where the object magnetic field is not applied to the magnetic sensor, the magnetization of the free layer includes a component in the first magnetic field direction, in the second resistor portion, in a case where the object magnetic field is not applied to the magnetic sensor, the magnetization of the free layer includes a component in the second magnetic field direction.

Images