Magnetic resistance effect element and magnetic sensor

Abstract

An MR element includes: a magnetized fixed layer; a free layer configured to have a magnetic vortex structure in which the center of the magnetic vortex structure can move according to a target magnetic field; and a gap layer disposed between the magnetized fixed layer and the free layer. The free layer has: a lower surface located at one end in the stacking direction of the magnetized fixed layer, the gap layer, and the free layer; an upper surface located at the other end in the stacking direction; and a side surface connecting the lower surface and the upper surface. The side surface includes an inclined portion inclined relative to the stacking direction.

Description

Technical Field

[0001] This disclosure relates to a magnetoresistive element and a magnetic sensor having a magnetoresistive element, wherein the magnetoresistive element has a free layer configured in a manner capable of having a magnetic vortex structure. Background Technology

[0002] In recent years, magnetic sensors have been used in various applications. Among magnetic sensors, those using a spin-valve type magnetoresistive effect element disposed on a substrate are known. The spin-valve type magnetoresistive effect element has: a magnetization fixed layer having magnetization with a fixed direction; a free layer having magnetization with an direction that can change according to the direction of the object's magnetic field; and a gap layer disposed between the magnetization fixed layer and the free layer.

[0003] U.S. Patent Application Publication No. 2023 / 0324477 discloses a magnetic sensor device having multiple TMR (tunneling magnetoresistive) elements. The TMR elements have a free layer with a disk-shaped structure. A magnetization pattern, also known as a vortex state, with closed magnetic flux is spontaneously formed on the free layer. In the magnetoresistive effect element described in U.S. Patent Application Publication No. 2023 / 0324477, which includes a free layer with a magnetic vortex structure, the center of the magnetic vortex structure moves according to the magnetic field of the object being detected, thereby changing the resistance value of the magnetoresistive effect element.

[0004] In magnetic sensors using magnetoresistive elements, it is preferable that the resistance value of the magnetoresistive element changes linearly or substantially linearly with respect to changes in the applied magnetic field, i.e., the linearity of the resistance value of the magnetoresistive element is good. As described in U.S. Patent Application Publication No. 2023 / 0324477, in a magnetoresistive element including a free layer with a magnetic vortex structure, the magnitude of the magnetization of the free layer as a whole changes substantially linearly with respect to changes in the applied magnetic field. Therefore, by using a magnetoresistive element including a free layer with a magnetic vortex structure, the linearity of the resistance value of the magnetoresistive element can be improved. In this magnetoresistive element, to further improve the linearity of the resistance value, it is necessary to improve the linearity of the magnitude of the magnetization of the free layer itself.

[0005] However, to improve the sensitivity of magnetic sensors, it is necessary to improve the sensitivity of the magnetoresistive element. In magnetoresistive elements comprising a free layer with a magnetic vortex structure, the sensitivity can be improved by constructing the free layer in a manner where the overall magnetization of the free layer varies significantly with changes in the applied magnetic field. However, currently, methods to improve both linearity and sensitivity through simple structures have not been sufficiently investigated in magnetoresistive elements comprising a free layer with a magnetic vortex structure. Summary of the Invention

[0006] One of the objectives of this disclosure is to provide a magnetoresistive element and a magnetic sensor having the magnetoresistive element, wherein the magnetoresistive element includes a free layer with a magnetic vortex structure, and the magnetoresistive element can improve linearity and sensitivity through a simple structure.

[0007] One embodiment of this disclosure provides a magnetoresistive effect element comprising: a magnetization fixed layer having magnetization of a fixed direction; a free layer configured to have a magnetic vortex structure in which the center of the magnetic vortex structure can move according to an object magnetic field; and a gap layer disposed between the magnetization fixed layer and the free layer. The free layer has: a first lower surface located at one end of the stacking direction of the magnetization fixed layer, the gap layer, and the free layer; a first upper surface located at the other end of the stacking direction; and a first side surface connecting the first lower surface and the first upper surface. The first side surface includes an inclined portion inclined relative to the stacking direction.

[0008] One embodiment of this disclosure provides a magnetic sensor comprising a plurality of magnetic detection elements. The plurality of magnetic detection elements are magnetoresistive elements according to an embodiment of this disclosure.

[0009] In the magnetoresistive effect element of this disclosure, the first side of the free layer includes an inclined portion that is tilted relative to the stacking direction. Therefore, according to this disclosure, a magnetoresistive effect element and a magnetic sensor capable of improving sensitivity and linearity can be realized.

[0010] Other objects, features and advantages of this disclosure will become fully apparent from the following description. Attached Figure Description

[0011] Figure 1 This is a top view illustrating a magnetic sensor according to a first exemplary embodiment of the present disclosure.

[0012] Figure 2 This is a circuit diagram illustrating the circuit structure of a magnetic sensor according to a first exemplary embodiment of the present disclosure.

[0013] Figure 3 This is a top view illustrating a portion of a magnetic sensor according to a first exemplary embodiment of the present disclosure.

[0014] Figure 4 This is a perspective view showing a magnetoresistive element in a first exemplary embodiment of the present disclosure.

[0015] Figure 5 This is a top view showing the free layer of the magnetoresistive effect element in a first exemplary embodiment of the present disclosure.

[0016] Figure 6This is an explanatory diagram showing the direction of magnetization of the free layer of the magnetoresistive element in a first exemplary embodiment of this disclosure.

[0017] Figure 7 This is an explanatory diagram showing the direction of magnetization of the free layer when a target magnetic field is applied to the magnetoresistive effect element in the first exemplary embodiment of this disclosure.

[0018] Figure 8 This is an explanatory diagram showing the direction of magnetization of the free layer when a target magnetic field is applied to the magnetoresistive effect element in the first exemplary embodiment of this disclosure.

[0019] Figure 9 This is a side view showing the free layer and magnetized fixed layer of the magnetoresistive effect element in a first exemplary embodiment of the present disclosure.

[0020] Figure 10 This is an explanatory diagram showing the relationship between the strength of the magnetic field component and the magnitude of the overall magnetization of the free layer in a first exemplary embodiment of this disclosure.

[0021] Figure 11 It is a characteristic diagram showing the relationship between the strength of the magnetic field component obtained through the first simulation and the magnitude of the overall magnetization of the free layer.

[0022] Figure 12 It is a characteristic graph showing the relationship between the tilt angle and the slope obtained through the first simulation.

[0023] Figure 13 It is a characteristic graph representing the relationship between tilt angle and linearity obtained through the first simulation.

[0024] Figure 14 It is a characteristic graph showing the relationship between the tilt angle and the strength of the magnetic field component that disappears from the magnetic vortex structure, obtained through the first simulation, and the relationship between the tilt angle and the strength of the magnetic field component generated by the magnetic vortex structure.

[0025] Figure 15 This is a characteristic graph showing the relationship between the strength and linearity of the magnetic field components obtained through the second simulation.

[0026] Figure 16 This is a side view showing a magnetoresistive element in a second exemplary embodiment of the present disclosure.

[0027] Figure 17 This is a side view showing the free layer and magnetized fixed layer of the magnetoresistive effect element in a second exemplary embodiment of the present disclosure.

[0028] Figure 18This is a characteristic graph showing the relationship between the strength of the magnetic field component obtained through the third simulation and the magnitude of the overall magnetization of the free layer.

[0029] Figure 19 It is a characteristic diagram showing the relationship between the strength of the magnetic field component obtained through the third simulation and the magnitude of the overall magnetization of the free layer.

[0030] Figure 20 It is a characteristic graph showing the relationship between tilt angle and slope obtained through the third simulation.

[0031] Figure 21 It is a characteristic graph showing the relationship between tilt angle and linearity obtained through the third simulation.

[0032] Figure 22 This is a side view showing a magnetoresistive element in a third exemplary embodiment of the present disclosure.

[0033] Figure 23 This is a side view showing the free layer and magnetized fixed layer of the magnetoresistive effect element in the third exemplary embodiment of this disclosure.

[0034] Figure 24 This is a characteristic graph showing the relationship between the strength of the magnetic field component obtained through the fourth simulation and the magnitude of the overall magnetization of the free layer.

[0035] Figure 25 This is a characteristic graph showing the relationship between the strength of the magnetic field component obtained through the fourth simulation and the overall magnetization of the free layer.

[0036] Figure 26 It is a characteristic graph showing the relationship between the tilt angle and the slope obtained through the fourth simulation.

[0037] Figure 27 It is a characteristic graph showing the relationship between tilt angle and linearity obtained through the fourth simulation. Detailed Implementation

[0038] [First Exemplary Implementation]

[0039] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, referring to... Figure 1 and Figure 2 A schematic structure of a magnetic sensor according to a first exemplary embodiment of the present disclosure will be described. Figure 1 This is a top view of a magnetic sensor 1 illustrating an exemplary embodiment. Figure 2 This is a circuit diagram illustrating the circuit structure of a magnetic sensor 1 according to an exemplary embodiment.

[0040] The magnetic sensor 1 of the exemplary embodiment includes a power supply terminal 11, a ground terminal 12, a first output terminal 13, a second output terminal 14, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a substrate 10. The first to fourth resistors R1 to R4, the power supply terminal 11, the ground terminal 12, and the first and second output terminals 13 and 14 are disposed on the substrate 10.

[0041] The first to fourth resistive sections R1 to R4 each include a plurality of magnetic detection elements, and each is configured to detect the magnetic field of the object and generate at least one detection signal. In particular, in the exemplary embodiment, the plurality of magnetic detection elements are a plurality of magnetoresistive effect elements. Hereinafter, magnetoresistive effect elements will be referred to as MR elements. Since the first to fourth resistive sections R1 to R4 each include a plurality of MR elements, it can also be said that the magnetic sensor 1 has a plurality of MR elements.

[0042] like Figure 2 As shown, the first resistor R1 is disposed between the power supply terminal 11 and the first output terminal 13 in the circuit structure. The second resistor R2 is disposed between the ground terminal 12 and the first output terminal 13 in the circuit structure. The third resistor R3 is disposed between the ground terminal 12 and the second output terminal 14 in the circuit structure. The fourth resistor R4 is disposed between the power supply terminal 11 and the second output terminal 14 in the circuit structure. Furthermore, in this application, the expression "in the circuit structure" is used to indicate the configuration on the circuit diagram, rather than the configuration in the physical structure.

[0043] A specific voltage or current is applied to power terminal 11. Ground terminal 12 is grounded.

[0044] Here, as Figure 1 As shown, the X, Y, and Z directions are defined. The X, Y, and Z directions are orthogonal to each other. Furthermore, the direction opposite to the X direction is designated as the -X direction, the direction opposite to the Y direction as the -Y direction, and the direction opposite to the Z direction as the -Z direction. In an exemplary embodiment, specifically, a direction perpendicular to the surface of the substrate 10 is designated as the Z direction.

[0045] Furthermore, hereinafter, the position in front of a reference point in the Z direction will be referred to as "above," and the position opposite to "above" relative to a reference point will be referred to as "below." Regarding the components of the magnetic sensor 1, the side located at the end in the Z direction will be referred to as the "upper surface," and the side located at the end in the -Z direction will be referred to as the "lower surface." Additionally, the expression "when viewed from a specific direction (e.g., the Z direction)" refers to viewing the object from a position away from or parallel to the specific direction, i.e., looking down at the object.

[0046] Figure 1 This example illustrates the arrangement of the first to fourth resistor sections R1 to R4. In this example, the first and second resistor sections R1 and R2 are arranged in a direction parallel to the X direction. The second resistor section R2 is positioned in front of the first resistor section R1 in the X direction.

[0047] The third and fourth resistors, R3 and R4, are arranged parallel to the X-direction. The fourth resistor, R4, is positioned in front of the third resistor, R3, in the -X-direction. Furthermore, the third resistor, R3, is positioned in front of the second resistor, R2, in the -Y-direction. The fourth resistor, R4, is positioned in front of the first resistor, R1, in the -Y-direction.

[0048] Furthermore, the configuration of the first to fourth resistor sections R1 to R4 is not limited to... Figure 1 The example shown. For example, the first to fourth resistor sections R1 to R4 may also be arranged in a specific order in a direction parallel to the X direction or in a direction parallel to the Y direction.

[0049] Next, refer to Figure 3 The specific structure of magnetic sensor 1 will be described in detail. Figure 3 This is a top view showing a portion of magnetic sensor 1.

[0050] In an exemplary embodiment, the magnetic sensor 1 includes a plurality of MR elements 50, and a plurality of lower electrodes 41 and a plurality of upper electrodes 42 for electrically connecting the plurality of MR elements 50. The plurality of lower electrodes 41 are disposed on a substrate 10 (see reference). Figure 1 Multiple MR elements 50 are disposed on multiple lower electrodes 41. Multiple upper electrodes 42 are disposed on multiple MR elements 50.

[0051] Multiple MR elements 50 can also be connected in series by multiple lower electrodes 41 and multiple upper electrodes 42. In this case, the connection method of the multiple MR elements 50 is as follows. Figure 3 As shown, each lower electrode 41 has an elongated shape. A gap is formed between two adjacent lower electrodes 41 along their long sides. MR elements 50 are disposed near both ends of the upper surface of the lower electrode 41 along its long side. Furthermore, each upper electrode 42 has an elongated shape and is disposed on two adjacent lower electrodes 41 along their long sides, electrically connecting two adjacent MR elements 50 to each other. Thus, multiple MR elements 50 are connected in series.

[0052] Next, refer to Figures 4 to 6 The structure of MR element 50 is described. Figure 4 This is a three-dimensional view of MR element 50. Figure 5 This is a top view showing the free layer of MR element 50. Figure 6This is an explanatory diagram showing the direction of magnetization of the free layer of MR element 50.

[0053] The MR element 50 includes: a magnetization fixed layer 51 having a magnetization 51m with a fixed direction; a free layer 53; a gap layer 52 disposed between the magnetization fixed layer 51 and the free layer 53; and a capping layer 54 disposed on the free layer 53. The free layer 53 is selected in terms of its material and shape to have a magnetic vortex structure (also known as a vortex state). The gap layer 52 is a tunnel barrier layer or a non-magnetic conductive layer. The capping layer 54 is made of, for example, a non-magnetic metallic material such as Ta or Ru.

[0054] At least a portion of the free layer 53 forms a frustum-shaped or substantially frustum-shaped structure. Figure 4 In the example shown, the free layer 53 is formed in a frustum shape, and the MR element 50 is formed in a frustum shape.

[0055] like Figure 5 As shown, the free layer 53 has: a lower surface 53a and an upper surface 53b located at both ends of the stacking direction of the magnetized fixed layer 51, the gap layer 52, and the free layer 53; and a side surface 53d connecting the lower surface 53a and the upper surface 53b. The lower surface 53a is located at the end of the free layer 53 in the -Z direction, opposite to the gap layer 52. The upper surface 53b is located at the end of the free layer 53 in the Z direction, opposite to the cover layer 54.

[0056] At least a portion of the side surface 53d is inclined relative to the stacking direction (i.e., the direction parallel to the Z direction). The side surface 53d can be planar or curved. The planar shape of the side surface 53d when viewed from a direction parallel to the stacking direction (i.e., the Z direction) can also be annular. The planar shapes (shapes viewed from the Z direction) of both the lower surface 53a and the upper surface 53b are circular. The planar shape of the upper surface 53b is smaller than that of the lower surface 53a. Figure 5 In the attached figures, reference numeral 53ae indicates the outer edge of the lower surface 53a when viewed from the Z direction, and reference numeral 53be indicates the outer edge of the upper surface 53b when viewed from the Z direction. When viewed from the stacking direction (Z direction), the outer edge 53be of the upper surface 53b is inside the outer edge 53ae of the lower surface 53a.

[0057] Figure 6This indicates the direction of magnetization of the free layer 53 in any cross-section parallel to the XY plane (a plane orthogonal to the stacking direction). The free layer 53 has a vortex-shaped magnetization 53m centered on the center 53c of the magnetic vortex structure. In the absence of a magnetic field applied to the MR element 50, the center 53c of the magnetic vortex structure is aligned with, or approximately aligned with, the axis of the frustum. The free layer 53 is configured such that the center 53c of the magnetic vortex structure can move according to the object's magnetic field MF.

[0058] When a component of the target magnetic field MF orthogonal to the Z direction is applied to the free layer 53, the center 53c of the magnetic vortex structure shifts. Within the range of variation in the intensity of this component, the free layer 53 is preferably unsaturated.

[0059] In an exemplary embodiment, the magnetization 51m of the magnetization fixing layer 51 includes a component in a direction parallel to the X direction. Furthermore, when the magnetization 51m of the magnetization fixing layer 51 includes a component in a specific direction, that component in the specific direction may also be the principal component of the magnetization 51m of the magnetization fixing layer 51. In an exemplary embodiment, when the magnetization 51m of the magnetization fixing layer 51 includes a component in a specific direction, the direction of the magnetization 51m of the magnetization fixing layer 51 becomes a specific direction or a substantially specific direction.

[0060] The MR element 50 may also include an antiferromagnetic layer. The antiferromagnetic layer is made of an antiferromagnetic material and generates exchange coupling with the magnetization fixation layer 51, fixing the direction of magnetization 51m of the magnetization fixation layer 51. Alternatively, the magnetization fixation layer 51 may also be a so-called self-pinned fixation layer (SFP layer). A self-pinned fixation layer has a stacked ferrite structure consisting of a stacked ferromagnetic layer, a non-magnetic intermediate layer, and a ferromagnetic layer, and is a fixation layer formed by antiferromagnetic coupling of two ferromagnetic layers.

[0061] Here, taking the case where the magnetization direction of the magnetization 51m of the magnetization fixation layer 51 is the -X direction as an example, the resistance value of the MR element 50 will be explained. Figure 7 and Figure 8 The free layer 53 represents the free layer 53 when the magnetic field component MFx of the object magnetic field MF in the direction parallel to the X direction is applied.

[0062] Figure 7 This represents the free layer 53 when the direction of the magnetic field component MFx is in the X direction. In this case, the center 53c of the magnetic vortex structure shifts due to the magnetic field component MFx, and the magnetization 53m in the X direction is greater than the magnetization 53m in the -X direction. In this case, the resistance of the MR element 50 increases.

[0063] Figure 8This represents the free layer 53 when the direction of the magnetic field component MFx is in the -X direction. In this case, the center 53c of the magnetic vortex structure shifts due to the magnetic field component MFx, and the magnetization 53m in the -X direction is greater than the magnetization 53m in the X direction. In this case, the resistance value of the MR element 50 decreases.

[0064] The change in resistance of MR element 50 depends on the strength of the magnetic field component MFx. When the direction of magnetic field component MFx is in the X direction, as the strength of magnetic field component MFx increases, the magnetization 53m in the X direction increases. The resistance of MR element 50 increases with the increase in magnetization 53m in the X direction. Conversely, when the direction of magnetic field component MFx is in the -X direction, as the strength of magnetic field component MFx increases, the magnetization 53m in the -X direction increases. The resistance of MR element 50 decreases with the increase in magnetization 53m in the -X direction. When the strength of magnetic field component MFx increases, the resistance of MR element 50 changes in the direction in which its increase or decrease both increase and decrease. When the strength of magnetic field component MFx decreases, the resistance of MR element 50 changes in the direction in which its increase or decrease both decrease. In an exemplary embodiment, in particular, the relationship between the intensity Hx of the magnetic field component MFx and the resistance value of the MR element 50 is linear or approximately linear as long as the requirement that the free layer 53 is unsaturated is met.

[0065] Next, refer to Figure 2 The directions of magnetization 51m in the magnetization fixing layers 51 of each of the first to fourth resistive sections R1 to R4 will be explained. In the first resistive section R1, the magnetization 51m of the magnetization fixing layers 51 of each of the plurality of MR elements 50 includes a component in a first magnetization direction. In the second resistive section R2, the magnetization 51m of the magnetization fixing layers 51 of each of the plurality of MR elements 50 includes a component in a second magnetization direction opposite to the first magnetization direction. In the third resistive section R3, the magnetization 51m of the magnetization fixing layers 51 of each of the plurality of MR elements 50 includes a component in the first magnetization direction. In the fourth resistive section R4, the magnetization 51m of the magnetization fixing layers 51 of each of the plurality of MR elements 50 includes a component in the second magnetization direction. Figure 2 In the diagram, the two arrows depicted in the first and third resistive sections R1 and R3 respectively indicate the first magnetization direction. Figure 2 In the diagram, the two arrows depicted in the second and fourth resistive sections R2 and R4 respectively indicate the second magnetization direction. In an exemplary embodiment, specifically, the first magnetization direction is the X direction, and the second magnetization direction is the -X direction.

[0066] Next, refer to Figure 2At least one detection signal generated by the magnetic sensor 1 will be explained. Compared to the state where there is no magnetic field component MFx, when the direction of the magnetic field component MFx is in the X direction, the resistance values ​​of each of the plurality of MR elements 50 in the first and third resistive sections R1 and R3 decrease, while the resistance values ​​of each of the plurality of MR elements 50 in the second and fourth resistive sections R2 and R4 increase. As a result, the resistance values ​​of each of the first and third resistive sections R1 and R3 decrease, while the resistance values ​​of each of the second and fourth resistive sections R2 and R4 increase.

[0067] When the direction of the magnetic field component MFx is in the -X direction, the change in resistance value of the first to fourth resistors R1 to R4 is opposite to that when the direction of the magnetic field component MFx is in the X direction.

[0068] Thus, when the direction and intensity of the magnetic field component MFx change, the resistance values ​​of the first to fourth resistive sections R1 to R4 change in the following manner: the resistance values ​​of the first and third resistive sections R1 and R3 increase, and the resistance values ​​of the second and fourth resistive sections R2 and R4 decrease; or, the resistance values ​​of the first and third resistive sections R1 and R3 decrease, and the resistance values ​​of the second and fourth resistive sections R2 and R4 increase. Consequently, the potential at the connection point of the first and second resistive sections R1 and R2 (i.e., the potential of the first output terminal 13) and the potential at the connection point of the third and fourth resistive sections R3 and R4 (i.e., the potential of the second output terminal 14) change. The magnetic sensor 1 may also generate a signal corresponding to the potential of the first output terminal 13 and a signal corresponding to the potential of the second output terminal 14 as detection signals, respectively. Alternatively, the magnetic sensor 1 may generate a signal corresponding to the potential difference between the first output terminal 13 and the second output terminal 14 as a detection signal. In this case, the magnetic sensor 1 further includes a differential amplifier (differential detector) that outputs the signal corresponding to the potential difference between the first output terminal 13 and the second output terminal 14 as a detection signal.

[0069] Next, refer to Figure 9 The shapes of the side surface 53d of the free layer 53 and the side surface of the magnetized fixed layer 51 will be described. Figure 9 This is a side view showing the free layer 53 and the magnetized fixed layer 51 of the MR element 50. The side 53d of the free layer 53 includes an inclined portion that is tilted relative to the stacking direction (i.e., a direction parallel to the Z direction). Figure 9 In the example shown, side 53d is entirely a sloping section. Additionally, in Figure 9 In the example shown, the entire side surface 53d (the inclined portion) is planar. However, at least a portion of the side surface 53d (the inclined portion) may also be curved. In addition to the inclined portion, the side surface 53d of the free layer 53 may also include a portion parallel or substantially parallel to the Z direction.

[0070] exist Figure 9 In this text, θ1 represents the angle formed by the inclined portion of the side surface 53d relative to the lower surface 53a of the free layer 53. Hereinafter, angle θ1 will be denoted as the inclination angle of the side surface 53d.

[0071] At least a portion of the magnetization fixing layer 51 forms a frustum-shaped or substantially frustum-shaped structure. The magnetization fixing layer 51 has a lower surface 51a and an upper surface 51b located at both ends in the stacking direction (i.e., a direction parallel to the Z direction), and a side surface 51d connecting the lower surface 51a and the upper surface 51b. The lower surface 51a is located at the -Z direction end of the magnetization fixing layer 51. The upper surface 51b is located at the Z direction end of the magnetization fixing layer 51 and is opposite to the gap layer 52.

[0072] Side 51d includes an inclined portion that is tilted relative to a direction parallel to the Z direction. Figure 9 In the example shown, side 51d is entirely a sloping section. Figure 9 In this text, θ2 represents the angle formed by the inclined portion of side surface 51d relative to the lower surface 51a of the magnetized fixing layer 51. Hereinafter, angle θ2 will be referred to as the inclination angle of side surface 51d. The inclination angle θ2 of side surface 51d may or may not be the same as the inclination angle θ1 of side surface 53d. Figure 9 In the example shown, the tilt angle θ2 of side 51d is the same as or approximately the same as the tilt angle θ1 of side 51d.

[0073] Next, refer to Figure 10 The relationship between the strength of the magnetic field component MFx and the overall magnetization of the free layer 53 is explained. Figure 10 This is a schematic diagram illustrating the relationship between the strength of the magnetic field component MFx and the overall magnetization of free layer 53. Figure 10 In the diagram, the horizontal axis represents the intensity Hx of the magnetic field component MFx, and the vertical axis represents the magnitude Mx of the overall magnetization of the free layer 53. Figure 10 In the diagram, a positive value represents the intensity Hx when the direction of the magnetic field component MFx is the X direction, and a negative value represents the intensity Hx when the direction of the magnetic field component MFx is the -X direction. When the direction of the magnetic field component MFx is the X direction, as the amount of magnetization 53m in the X direction increases, the magnitude Mx of the overall magnetization of the free layer 53 increases. When the direction of the magnetic field component MFx is the -X direction, as the amount of magnetization 53m in the -X direction increases, the magnitude Mx of the overall magnetization of the free layer 53 decreases.

[0074] First, let's explain the case where the intensity Hx is increased from 0. As the intensity Hx is gradually increased from 0, the magnitude of magnetization Mx gradually increases. When the intensity Hx reaches a value greater than Hx1, the magnitude of magnetization Mx becomes constant, and the free layer 53 becomes magnetically saturated.

[0075] Next, the case where the intensity Hx is decreased from 0 will be explained. As the intensity Hx is gradually decreased from 0, the magnitude of magnetization Mx also gradually decreases. When the intensity Hx becomes below Hx2, the magnitude of magnetization Mx remains constant, and the free layer 53 becomes magnetically saturated.

[0076] like Figure 10 As shown, within a specific range where the intensity Hx is greater than the ratio Hx2 and less than the ratio Hx1, the magnitude of magnetization Mx changes linearly with respect to the intensity Hx. Furthermore, "changing linearly" means that, in the characteristic graph representing the relationship between intensity Hx and the magnitude of magnetization Mx, the magnitude of magnetization Mx changes linearly or approximately linearly with respect to the intensity Hx.

[0077] In an exemplary embodiment, within the range of variation of intensity Hx, the free layer 53 is preferably not magnetically saturated, and more preferably the magnitude of magnetization Mx varies linearly with respect to the variation of intensity Hx.

[0078] Furthermore, when the intensity Hx is greater than Hx1 and the free layer 53 is magnetically saturated, if the intensity Hx is reduced from a value Hx3 (which is greater than Hx1) until it reaches a value Hx4 (which is less than Hx1), the magnitude of magnetization Mx remains almost unchanged. When the intensity Hx is less than Hx4, similar to the case where the intensity Hx varies within a specific range where it is greater than Hx2 and less than Hx1, the magnitude of magnetization Mx changes linearly with respect to the change in intensity Hx.

[0079] Similarly, when the intensity Hx is less than Hx2 and the free layer 53 is magnetically saturated, if the intensity Hx is increased from a value Hx5 (smaller than Hx2) until it reaches a value Hx6 (larger than Hx2), the magnetization Mx remains almost unchanged. When the intensity Hx is greater than Hx6, similar to the case where the intensity Hx varies within a specific range that is larger than Hx2 and smaller than Hx1, the magnetization Mx changes linearly with respect to the intensity Hx.

[0080] Although not illustrated, the relationship between intensity Hx and the resistance of MR element 50 is the same as the relationship between intensity Hx and the overall magnetization of free layer 53.

[0081] Next, the results of the first and second simulations investigating the effect of the tilt angle θ1 of the side surface 53d of the free layer 53 on the characteristics of the MR element 50 will be explained. First, the first simulation will be described. In the first simulation, the diameter of the lower surface 53a of the free layer 53 was set to be the same, while the tilt angle θ1 was varied within the range of 30° to 90°. Then, the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of the magnetization was obtained at each tilt angle θ1. In the first simulation, the diameter of the lower surface 53a of the free layer 53 was set to 500 nm. Furthermore, when the tilt angle θ1 is 90°, the free layer 53 has a cylindrical or approximately cylindrical shape.

[0082] Furthermore, based on the relationship between the intensity Hx of the magnetic field component MFx and the magnitude of magnetization Mx, the ratio of the change in the magnitude of magnetization Mx to the change in the intensity Hx of the magnetic field component MFx is calculated, i.e., the slope. The slope is obtained within the range of the intensity Hx of the magnetic field component MFx in the free layer 53 when it is not magnetically saturated. The slope is a parameter corresponding to the sensitivity of the MR element 50. The larger the slope, the higher the sensitivity of the MR element 50.

[0083] Furthermore, the linearity of the magnetization magnitude Mx is obtained based on the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of magnetization. Linearity is defined using a characteristic curve representing the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of magnetization, and an approximate straight line of that characteristic curve. That is, linearity is the residual between the value on the approximate straight line and the value on the characteristic curve when the intensity Hx of the magnetic field component MFx is set to the same value. Linearity is obtained within the range of the intensity Hx of the magnetic field component MFx in the unsaturated free layer 53. It can be said that the smaller the linearity value, the better the linearity.

[0084] Furthermore, based on the relationship between the intensity Hx of the magnetic field component MFx and the magnitude of magnetization Mx, the intensity Ha of the magnetic field component MFx at which the magnetic vortex structure disappears when the intensity Hx of the magnetic field component MFx is increased (equivalent to...). Figure 10 Hx1), and the intensity Hn of the magnetic field component MFx that generates the magnetic vortex structure when the intensity Hx of the magnetic field component MFx is reduced after the free layer 53 is magnetically saturated (equivalent to Hn). Figure 10 (Hx4 in the text). The greater the intensity Ha and Hn of the magnetic field component MFx, the wider the measurement range of the magnetic field component MFx can be.

[0085] Figure 11 This is a characteristic graph representing the relationship between the intensity Hx of the magnetic field component MFx and the magnitude of magnetization Mx. Figure 11 In the diagram, the horizontal axis represents the intensity Hx (in mT), and the vertical axis represents the magnitude of magnetization Mx (in T). Figure 11In the figures, reference numeral 71 indicates the case where the tilt angle θ1 is 90°, reference numeral 72 indicates the case where the tilt angle θ1 is 75°, reference numeral 73 indicates the case where the tilt angle θ1 is 60°, reference numeral 74 indicates the case where the tilt angle θ1 is 45°, and reference numeral 75 indicates the case where the tilt angle θ1 is 30°.

[0086] Figure 12 This is a characteristic graph representing the relationship between the tilt angle θ1 and the slope. In Figure 12 In the diagram, the horizontal axis represents the tilt angle θ1, and the vertical axis represents the slope. Furthermore, in... Figure 12 In this process, the ratio of the change in magnetization Mx (in T) to the change in intensity Hx (in A / m) is calculated and used as the slope. Specifically, at each tilt angle θ1, when the magnitude of intensity Hx is greater than or equal to 0 and 4.8 × 10⁻⁶, the slope is calculated. 4 Within the following range, the slope of an approximate straight line is obtained by linearizing the characteristic curve representing the relationship between intensity Hx and magnetization Mx. Then, in... Figure 12 In the diagram, lines are used to connect the slopes at each tilt angle θ1. Furthermore, in conjunction with the descriptions below... Figure 12 In the same graph, the method for calculating the slope is also the same. Figure 12 The method for finding them is the same. For example... Figure 12 As shown, the slope increases as the tilt angle θ1 decreases.

[0087] Figure 13 This is a characteristic graph representing the relationship between the tilt angle θ1 and linearity. In Figure 13 In the diagram, the horizontal axis represents the tilt angle θ1, and the vertical axis represents the linearity. Furthermore, in... Figure 13 In this context, the unit of linearity is set to T. Figure 13 In the equation, the intensity Hx, obtained as a measure of linearity, is 4.8 × 10⁻⁶. 4 The residuals between the values ​​on the approximate straight line and the values ​​on the characteristic curve at A / m. Then, in Figure 13 In the diagram, linearity is determined by connecting lines at each tilt angle θ1. Furthermore, in conjunction with the descriptions below... Figure 13 In the same graph, the method for calculating linearity is also the same. Figure 13 The method for finding them is the same. For example... Figure 13 As shown, when the tilt angle θ1 is below 75°, the linearity value decreases as the tilt angle θ1 decreases.

[0088] Figure 14 This is a characteristic graph showing the relationship between the tilt angle θ1 and the intensity Ha of the magnetic field component MFx when the magnetic vortex structure disappears, and the relationship between the tilt angle θ1 and the intensity Hn of the magnetic field component MFx that generates the magnetic vortex structure. Figure 14 In the figure, the horizontal axis represents the tilt angle θ1, and the vertical axis represents the intensities Ha and Hn (unit: mT). Additionally, reference numeral 76 indicates intensity Ha, and reference numeral 77 indicates intensity Hn. (For example...) Figure 14 As shown, when the tilt angle θ1 is below 75°, the intensities Ha and Hn decrease as the tilt angle θ1 decreases.

[0089] The results of the first simulation show that by reducing the tilt angle θ1, the slope increases and the linearity decreases. That is, according to the exemplary embodiment, a simple structure such as providing a tilted portion on the side 53d of the free layer 53 can improve both linearity and sensitivity.

[0090] According to the results of the first simulation, the tilt angle θ1 is preferably below 60°. On the other hand, as... Figure 14 As shown, when the tilt angle θ1 decreases, the intensities Ha and Hn decrease. From the viewpoint of expanding the measurement range of the magnetic field component MFx to a certain extent, the tilt angle θ1 is preferably 30° or more.

[0091] Next, the second simulation will be described. In the second simulation, the model of the embodiment and the model of the comparative example are used. The model of the embodiment is the model of the free layer 53 in the exemplary embodiment. In the model of the embodiment, the tilt angle θ1 is set to 45°. The model of the comparative example is the model of the free layer 53 of the comparative example with the tilt angle θ1 set to 90°.

[0092] In both the embodiment and the comparative example models, the diameter of the lower surface 53a of the free layer 53 is designed in the same manner as the ratio (i.e., slope) of the change in magnetization magnitude Mx to the change in intensity Hx of the magnetic field component MFx. In the embodiment model, the diameter of the lower surface 53a of the free layer 53 is set to 500 nm. In the comparative example model, the diameter of the lower surface 53a of the free layer 53 is set to 530 nm.

[0093] In the second simulation, the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of magnetization was obtained for both the model of the embodiment and the model of the comparative example. Then, the linearity of the magnitude Mx of magnetization was obtained based on the obtained relationship. In particular, the value of the linearity was obtained for each intensity Hx in the second simulation.

[0094] Figure 15 This is a characteristic graph representing the relationship between intensity Hx and linearity. In Figure 15In the figure, the horizontal axis represents intensity Hx (in mT), and the vertical axis represents linearity (in T). Additionally, the curve labeled 78 represents the linearity of the model in the embodiment. The curve labeled 79 represents the linearity of the model in the comparative example. Figure 15 As shown, the linearity value of the model in the embodiment (reference numeral 78) is smaller than the linearity value of the model in the comparative example (reference numeral 79).

[0095] As can be seen from the second simulation, according to the exemplary implementation, linearity can be improved by providing an inclined portion on the side 53d of the free layer 53.

[0096] Furthermore, although not illustrated, similar to the first simulation, the intensities Ha and Hn are smaller in the embodiment model compared to the comparative example model. Therefore, it is preferable to determine the tilt angle θ1 while taking into account the intensities Ha and Hn.

[0097] [Second Exemplary Implementation]

[0098] Next, a second exemplary embodiment of this disclosure will be described. In this exemplary embodiment, the magnetic sensor 1 includes an MR element 150 instead of the MR element 50 in the first exemplary embodiment. Hereinafter, reference will be made to... Figure 16 and Figure 17 The structure of MR element 150 is described. Figure 16 This is a side view of MR element 150. Figure 17 This is a side view showing the free layer and magnetized fixed layer of the MR element 150.

[0099] The MR element 150 includes: a magnetization fixing layer 151 having magnetization with a fixed direction; a free layer 153; a gap layer 152 disposed between the magnetization fixing layer 151 and the free layer 153; and a cover layer 154 disposed on the free layer 153. The structures of the magnetization fixing layer 151, the gap layer 152, the free layer 153, and the cover layer 154 are identical to those of the magnetization fixing layer 51, the gap layer 52, the free layer 53, and the cover layer 54 in the first exemplary embodiment, except for the shapes of the magnetization fixing layer 151 and the free layer 153, which will be described later.

[0100] In an exemplary embodiment, in particular, a portion of the free layer 53 is in the shape of a frustum or substantially frustum, and another portion of the free layer 53 is in the shape of a frustum or substantially frustum, which is different from the aforementioned portion.

[0101] like Figure 17As shown, the free layer 153 has: a lower surface 153a and an upper surface 153b located at both ends of the magnetized fixed layer 151, the gap layer 152, and the free layer 153 in the stacking direction; and a side surface 153d connecting the lower surface 153a and the upper surface 153b. The lower surface 153a is located at the end of the free layer 153 in the -Z direction and is opposite to the gap layer 152. The upper surface 153b is located at the end of the free layer 153 in the Z direction and is opposite to the cover layer 154.

[0102] Side 153d includes a first portion 153d1 and a second portion 153d2 located between the first portion 153d1 and the upper surface 153b. At least one of the first portion 153d1 and the second portion 153d2 corresponds to an inclined portion, which is inclined relative to the stacking direction (i.e., a direction parallel to the Z direction). When the first portion 153d1 corresponds to the inclined portion, the second portion 153d2 may also correspond to the inclined portion. Alternatively, when the first portion 153d1 corresponds to the inclined portion, the second portion 153d2 may not correspond to the inclined portion. That is, the second portion 153d2 may not be inclined relative to the direction parallel to the Z direction. In an exemplary embodiment, specifically, both the first portion 153d1 and the second portion 153d2 correspond to the inclined portion.

[0103] The planar shape of the side 153d when viewed from a direction parallel to the stacking direction (i.e., the Z direction) can also be an annular shape. In addition, the planar shapes of the first part 153d1 and the second part 153d2 when viewed from the Z direction are both annular shapes.

[0104] exist Figure 17 In this diagram, θ3 represents the angle formed by the first portion 153d1 of the side surface 153d relative to the lower surface 153a of the free layer 153. Hereinafter, angle θ3 will be referred to as the tilt angle of the first portion 153d1. Similarly, θ4 represents the angle formed by the second portion 153d2 of the side surface 153d relative to the lower surface 153a of the free layer 153. Hereinafter, angle θ4 will be referred to as the tilt angle of the second portion 153d2. Furthermore, in... Figure 17 For convenience, the tilt angle θ4 of the second part 153d2 is represented as the angle between the second part 153d2 and the imaginary plane P1, which is parallel to the lower surface 153a of the free layer 153. The tilt angle θ3 of the first part 153d1 can also be smaller than the tilt angle θ4 of the second part 153d2.

[0105] The magnetization fixing layer 151 is frustum-shaped or approximately frustum-shaped. The magnetization fixing layer 151 has a lower surface 151a and an upper surface 151b located at both ends in the stacking direction (i.e., parallel to the Z direction), and a side surface 151d connecting the lower surface 151a and the upper surface 151b. The lower surface 151a is located at the -Z direction end of the magnetization fixing layer 151. The upper surface 151b is located at the Z direction end of the magnetization fixing layer 151 and is opposite to the gap layer 152.

[0106] Side 151d includes an inclined portion that is inclined relative to the stacking direction (i.e., a direction parallel to the Z direction). Figure 17 In the example shown, side 151d is entirely a sloping section. Figure 17 In the diagram, θ5 represents the angle formed by the inclined portion of the side surface 151d relative to the lower surface 151a of the magnetized fixing layer 151. Hereinafter, angle θ5 will be referred to as the inclination angle of the side surface 151d.

[0107] In an exemplary embodiment, the absolute value of the difference between the tilt angle θ3 of the first portion 153d1 and the tilt angle θ5 of the side 151d may also be smaller than the absolute value of the difference between the tilt angle θ4 of the second portion 153d2 and the tilt angle θ5 of the side 151d. Furthermore, the tilt angle θ5 of the side 151d may also be the same as or approximately the same as the tilt angle θ3 of the first portion 153d1.

[0108] Next, the results of a third simulation investigating the effect of the tilt angle θ3 of the first portion 153d1 of the side surface 153d of the free layer 153 on the characteristics of the MR element 150 will be presented. In the third simulation, the diameters of the lower surface 153a, the upper surface 153b, and the dimensions of the free layer 153 in the direction parallel to the Z direction were set to be the same, while the tilt angle θ3 was varied within the range of 5° to 30°. Then, the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of the magnetization was obtained at each tilt angle θ3.

[0109] In the third simulation, the diameter of the lower surface 153a of the free layer 153 was set to 589 nm, the diameter of the upper surface 153b of the free layer 153 was set to 471 nm, and the size of the free layer 153 in the direction parallel to the Z direction was set to 50 nm. Additionally, in the third simulation, the tilt angle θ4 of the second portion 153d2 of the side surface 153d was set to 60°.

[0110] In the third simulation, the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of magnetization was also obtained for the case where the side surface 153d of the free layer 153 includes only the second portion 153d2 and not the first portion 153d1. In this case, the shape of the free layer 153 is actually the same as that of the free layer 53 in the first exemplary embodiment, except that the tilt angle θ1 of the side surface 53d is set to 60°.

[0111] Furthermore, based on the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of magnetization, the ratio of the change in the magnitude Mx of magnetization to the change in the intensity Hx of the magnetic field component MFx is obtained, i.e., the slope. The slope is obtained within the range of the intensity Hx of the magnetic field component MFx in the free layer 153 where it is not magnetically saturated.

[0112] Furthermore, based on the relationship between the intensity Hx of the magnetic field component MFx and the magnitude of magnetization Mx, the linearity of the magnitude of magnetization Mx is obtained. The linearity is obtained within the range of the intensity Hx of the magnetic field component MFx in the free layer 153 when it is not magnetically saturated.

[0113] Figure 18 and Figure 19 This is a characteristic graph representing the relationship between the intensity Hx of the magnetic field component MFx and the magnitude of magnetization Mx. Figure 18 and Figure 19 In the diagram, the horizontal axis represents the intensity Hx, and the vertical axis represents the magnitude of magnetization Mx. Furthermore, in... Figure 18 and Figure 19 In this context, the unit of intensity Hx is set to A / m, and the unit of magnetization magnitude Mx is set to T. Figure 18 This represents the relationship between the intensity Hx and the magnitude of magnetization Mx when the free layer 153 is magnetically saturated by increasing the intensity Hx from 0. Figure 19 This represents the relationship between the intensity Hx and the magnitude of magnetization Mx when the intensity Hx is increased from 0 to saturate the free layer 153 magnetically and then the intensity Hx is reduced.

[0114] exist Figure 18 and Figure 19 In the figure, reference numeral 81 indicates that the side 153d of the free layer 153 includes only the second part 153d2 and does not include the first part 153d1; reference numeral 82 indicates that the tilt angle θ3 is 5°; reference numeral 83 indicates that the tilt angle θ3 is 10°; reference numeral 84 indicates that the tilt angle θ3 is 20°; and reference numeral 85 indicates that the tilt angle θ3 is 30°.

[0115] Figure 20 This is a characteristic graph showing the relationship between the tilt angle θ3 and the slope. In Figure 20In the diagram, the horizontal axis represents the tilt angle θ3, and the vertical axis represents the slope. Figure 20 In the diagram, lines are used to connect the slopes at each inclination angle θ3. Additionally, in... Figure 20 For convenience, the side surface 153d of the free layer 153 is shown to include only the second part 153d2 and not the first part 153d1. Figure 18 and Figure 19 The slope of the figure (81) is depicted as the slope when the tilt angle θ3 is 0°. For example... Figure 20 As shown, the slope increases with the increase of the tilt angle θ3.

[0116] Figure 21 This is a characteristic graph representing the relationship between the tilt angle θ3 and linearity. In Figure 21 In the diagram, the horizontal axis represents the tilt angle θ3, and the vertical axis represents the linearity. Figure 21 In this context, linearity is assessed by connecting lines at each tilt angle θ3. Additionally, in... Figure 21 For convenience, the side surface 153d of the free layer 153 is shown to include only the second part 153d2 and not the first part 153d1. Figure 18 and Figure 19 The linearity of the figure (81) is described as the linearity when the tilt angle θ3 is 0°. For example... Figure 21 As shown, when the tilt angle θ3 is above 0° and below 20°, the linearity value increases as the tilt angle θ3 increases.

[0117] The results of the third simulation show that the slope increases by increasing the tilt angle θ3. That is, according to the exemplary embodiment, the sensitivity of the MR element 150 can be improved by providing a simple structure such as the first part 153d1 on the side 153d of the free layer 153.

[0118] In addition, such as Figure 21 As shown, when the tilt angle θ3 is 0° or more and 20° or less, the linearity value increases as the tilt angle θ3 increases. From the viewpoint of suppressing the deterioration of the linearity of the MR element 150, it is preferable to determine the tilt angle θ3 while considering the linearity value.

[0119] Other structures, functions, and effects in the exemplary embodiments are the same as in the first exemplary embodiment.

[0120] [Third exemplary implementation]

[0121] Next, a third exemplary embodiment of this disclosure will be described. In this exemplary embodiment, the magnetic sensor 1 includes an MR element 250 instead of the MR element 50 in the first exemplary embodiment. Hereinafter, reference will be made to... Figure 22 and Figure 23 The structure of MR element 250 is described. Figure 22 This is a side view of MR element 250. Figure 23 This is a side view showing the free layer and magnetized fixed layer of the MR element 250.

[0122] The MR element 250 includes: a magnetization fixation layer 251 having magnetization with a fixed direction; a free layer 253; a gap layer 252 disposed between the magnetization fixation layer 251 and the free layer 253; and a cover layer 254 disposed on the free layer 253. The structures of the magnetization fixation layer 251, the gap layer 252, the free layer 253, and the cover layer 254 are identical to those of the magnetization fixation layer 51, the gap layer 52, the free layer 53, and the cover layer 54 in the first exemplary embodiment, except for the shapes of the magnetization fixation layer 251 and the free layer 253, which will be described later.

[0123] In an exemplary embodiment, in particular, a portion of the free layer 53 is frustum-shaped or substantially frustum-shaped, and another portion of the free layer 53 is cylindrical or substantially cylindrical.

[0124] like Figure 23 As shown, the free layer 253 has: a lower surface 253a and an upper surface 253b located at both ends of the stacking direction of the magnetized fixed layer 251, the gap layer 252, and the free layer 253; and a side surface 253d connecting the lower surface 253a and the upper surface 253b. The lower surface 253a is located at the end of the free layer 253 in the -Z direction, opposite to the gap layer 252. The upper surface 253b is located at the end of the free layer 253 in the Z direction.

[0125] The side surface 253d includes a first portion 253d1 and a second portion 253d2 located between the first portion 253d1 and the upper surface 253b. At least one of the first portion 253d1 and the second portion 253d2 corresponds to an inclined portion that is inclined relative to the stacking direction (i.e., a direction parallel to the Z direction). When the second portion 253d2 corresponds to the inclined portion, the first portion 253d1 may not correspond to the inclined portion. That is, the first portion 253d1 may not be inclined relative to the direction parallel to the Z direction. Alternatively, when the second portion 253d2 corresponds to the inclined portion, the first portion 253d1 may also correspond to the inclined portion. In an exemplary embodiment, specifically, the second portion 253d2 corresponds to the inclined portion, and the first portion 253d1 does not correspond to the inclined portion.

[0126] The planar shape of the side 253d when viewed from a direction parallel to the stacking direction (i.e., the Z direction) can also be an annular shape. Additionally, the planar shape of the second part 253d2 when viewed from the Z direction can also be an annular shape.

[0127] exist Figure 23 In this designation, θ6 represents the angle formed by the first portion 253d1 of the side surface 253d relative to the lower surface 253a of the free layer 253. Angle θ6 is 90° or approximately 90°. Hereinafter, for convenience, angle θ6 will be referred to as the tilt angle of the first portion 253d1. Furthermore, θ7 represents the angle formed by the second portion 253d2 of the side surface 253d relative to the lower surface 253a of the free layer 253. Hereinafter, angle θ7 will be referred to as the tilt angle of the second portion 253d2. Additionally, in... Figure 23 For convenience, the tilt angle θ7 of the second part 253d2 is represented as the angle between the second part 253d2 and the imaginary plane P2, which is parallel to the lower surface 253a of the free layer 253. The tilt angle θ7 of the second part 153d2 can also be smaller than the tilt angle θ6 of the first part 153d1.

[0128] The magnetization fixing layer 251 is cylindrical or substantially cylindrical in shape. The magnetization fixing layer 251 has a lower surface 251a and an upper surface 251b located at both ends in the stacking direction (i.e., parallel to the Z direction), and a side surface 251d connecting the lower surface 251a and the upper surface 251b. The lower surface 251a is located at the -Z end of the magnetization fixing layer 251. The upper surface 251b is located at the Z end of the magnetization fixing layer 251, opposite to the gap layer 252.

[0129] exist Figure 23 In the diagram, θ8 represents the angle between the side surface 251d and the lower surface 251a of the magnetized fixing layer 251. The angle θ8 is 90° or approximately 90°. Hereinafter, for convenience, the angle θ8 will be referred to as the tilt angle of the side surface 251d.

[0130] In an exemplary embodiment, the absolute value of the difference between the tilt angle θ6 of the first portion 253d1 and the tilt angle θ8 of the side surface 251d may also be less than the absolute value of the difference between the tilt angle θ7 of the second portion 253d2 and the tilt angle θ8 of the side surface 251d. Furthermore, the tilt angle θ8 of the side surface 251d may be the same as or approximately the same as the tilt angle θ6 of the first portion 253d1.

[0131] Next, the results of a fourth simulation investigating the effect of the tilt angle θ7 of the second portion 253d2 of the side surface 253d of the free layer 253 on the characteristics of the MR element 250 are presented. In the fourth simulation, the diameter of the lower surface 253a of the free layer 253, the size of the first portion 253d1 of the side surface 253d in the direction parallel to the Z direction, and the size of the second portion 253d2 of the side surface 253d in the direction parallel to the Z direction were set to be the same, while the tilt angle θ7 was varied within the range of 40° to 90°. Then, the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of the magnetization was obtained at each tilt angle θ7. Furthermore, when the tilt angle θ7 is 90°, the free layer 253 has a cylindrical or approximately cylindrical shape.

[0132] In the fourth simulation, the diameter of the lower surface 253a of the free layer 253 is set to 500 nm, the size of the first part 253d1 of the side surface 253d in the direction parallel to the Z direction is set to 20 nm, and the size of the second part 253d2 of the side surface 253d in the direction parallel to the Z direction is set to 30 nm.

[0133] Furthermore, based on the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of magnetization, the ratio of the change in the magnitude Mx of magnetization to the change in the intensity Hx of the magnetic field component MFx is obtained, i.e., the slope. The slope is obtained within the range of the intensity Hx of the magnetic field component MFx in the free layer 253 when it is not magnetically saturated.

[0134] Furthermore, the linearity of the magnetization magnitude Mx is obtained based on the relationship between the intensity Hx of the magnetic field component MFx and the magnitude Mx of magnetization. The linearity is obtained within the range of the intensity Hx of the magnetic field component MFx in the free layer 253 when it is not magnetically saturated.

[0135] Figure 24 and Figure 25 This is a characteristic graph representing the relationship between the intensity Hx of the magnetic field component MFx and the magnitude of magnetization Mx. Figure 24 and Figure 25 In the diagram, the horizontal axis represents the intensity Hx, and the vertical axis represents the magnitude of magnetization Mx. Furthermore, in... Figure 24 and Figure 25 In this context, the unit of intensity Hx is set to A / m, and the unit of magnetization Mx is set to T. Figure 24 This represents the relationship between the intensity Hx and the magnitude of magnetization Mx when the intensity Hx is increased from 0 to achieve magnetic saturation of the free layer 253. Figure 25 This represents the relationship between the intensity Hx and the magnitude of magnetization Mx when the intensity Hx is increased from 0 to saturate the free layer 253 magnetically and then the intensity Hx is reduced.

[0136] exist Figure 24 and Figure 25 In the attached figures, reference numeral 91 indicates the case where the tilt angle θ7 is 90°, reference numeral 92 indicates the case where the tilt angle θ7 is 80°, reference numeral 93 indicates the case where the tilt angle θ7 is 70°, reference numeral 94 indicates the case where the tilt angle θ7 is 60°, reference numeral 95 indicates the case where the tilt angle θ7 is 50°, and reference numeral 96 indicates the case where the tilt angle θ7 is 40°. Figure 24 In the figure, except for the case where the angle θ7 is 40° (Figure 96), the curves showing the relationship between the intensity Hx and the magnitude of magnetization Mx at each tilt angle θ7 almost overlap. Figure 25 In the figure, the curves mentioned above when angle θ7 is 90° (reference numeral 91) and when angle θ7 is 80° (reference numeral 92) almost overlap. Furthermore, in Figure 25 In the figure, the curves mentioned above when the angle θ7 is 70° (reference numeral 93) and the curves mentioned above when the angle θ7 is 60° (reference numeral 94) almost overlap.

[0137] Figure 26 This is a characteristic graph showing the relationship between the tilt angle θ7 and the slope. In Figure 26 In the diagram, the horizontal axis represents the tilt angle θ7, and the vertical axis represents the slope. Figure 26 In the diagram, lines are used to connect the slopes at each inclination angle θ7. For example... Figure 26 As shown, when the tilt angle θ7 is 30° or more and 60° or less, the slope increases as the tilt angle θ7 decreases. Conversely, when the tilt angle θ7 is 60° or more and 90° or less, the slope decreases as the tilt angle θ7 decreases.

[0138] Figure 27 This is a characteristic graph representing the relationship between the tilt angle θ7 and linearity. In Figure 27 In the diagram, the horizontal axis represents the tilt angle θ7, and the vertical axis represents linearity. Figure 27 In this context, linearity is determined by connecting lines at each tilt angle θ7. For example... Figure 27 As shown, when the tilt angle θ7 is above 50° and below 90°, the linearity value decreases as the tilt angle θ7 decreases.

[0139] The results of the fourth simulation show that the linearity value decreases by reducing the tilt angle θ7. That is, according to the exemplary embodiment, the linearity can be improved by providing a simple structure such as a second part 253d2 on the side 253d of the free layer 253.

[0140] In addition, such as Figure 26As shown, when the tilt angle θ7 is 60° or more and 90° or less, the slope decreases as the tilt angle θ7 decreases. From the viewpoint of suppressing the deterioration of the sensitivity of the MR element 250, it is preferable to determine the tilt angle θ7 while taking the slope into account.

[0141] Other structures, functions, and effects in the exemplary embodiments are the same as in the first exemplary embodiment.

[0142] Furthermore, this disclosure is not limited to the exemplary embodiments described above, and various modifications are possible. For example, the shape of the side surface 53d of the free layer 53 of the MR element 50 is not limited to the examples shown in the exemplary embodiments. For example, the side surface 53d of the free layer 53 may also include three or more portions with different tilt angles.

[0143] As described above, a magnetoresistive effect element according to one embodiment of the present disclosure includes: a magnetization fixed layer having magnetization in a fixed direction; a free layer configured to have a magnetic vortex structure in which the center of the magnetic vortex structure can move according to the object's magnetic field; and a gap layer disposed between the magnetization fixed layer and the free layer. The free layer has: a first lower surface located at one end of the stacking direction of the magnetization fixed layer, the gap layer, and the free layer; a first upper surface located at the other end of the stacking direction; and a first side surface connecting the first lower surface and the first upper surface. The first side surface includes an inclined portion inclined relative to the stacking direction.

[0144] In one embodiment of the magnetoresistive effect element of this disclosure, the first side may include a first portion and a second portion located between the first portion and the first upper surface. One of the first portion and the second portion may also be an inclined portion.

[0145] Furthermore, in one embodiment of the magnetoresistive effect element of this disclosure, the first portion may also be an inclined portion. The angle formed by the first portion relative to the first lower surface may also be smaller than the angle formed by the second portion relative to the first lower surface.

[0146] Furthermore, in one embodiment of the magnetoresistive effect element of this disclosure, the second portion may also be an inclined portion. The angle formed by the second portion relative to the first lower surface may also be smaller than the angle formed by the first portion relative to the first lower surface. The first portion may also be inclined relative to the stacking direction.

[0147] Alternatively, in one embodiment of the magnetoresistive effect element of this disclosure, the magnetization fixing layer may have: a second lower surface located at one end in the stacking direction, a second upper surface located at the other end in the stacking direction, and a second side surface connecting the second lower surface and the second upper surface. The second side surface may also include a third portion inclined relative to the stacking direction. The first side surface may also include a first portion and a second portion located between the first portion and the first upper surface. The first portion may also be an inclined portion. When the angle formed by the first portion relative to the first lower surface is defined as a first angle, the angle formed by the second portion relative to the first lower surface is defined as a second angle, and the angle formed by the third portion relative to the second lower surface is defined as a third angle, the absolute value of the difference between the first angle and the third angle may also be less than the absolute value of the difference between the second angle and the third angle.

[0148] Alternatively, in one embodiment of the magnetoresistive effect element of this disclosure, the planar shape of the inclined portion when viewed from the stacking direction may be an annular shape.

[0149] One embodiment of the magnetic sensor disclosed herein is a magnetic sensor having multiple magnetic detection elements. These multiple magnetic detection elements are magnetoresistive elements according to one embodiment of the present disclosure.

[0150] Clearly, various methods and variations of this disclosure can be implemented based on the foregoing description. Therefore, within the scope of the claims, this disclosure can be implemented even in ways other than the exemplary embodiments described above.

Claims

1. A magnetoresistive effect element, characterized in that, have: A magnetization fixation layer having magnetization with a fixed orientation; A free layer, which is configured to have a magnetic vortex structure and the center of the magnetic vortex structure can move according to the magnetic field of the object; as well as A gap layer is disposed between the magnetized fixed layer and the free layer. The free layer has: a first lower surface located at one end of the stacking direction of the magnetized fixed layer, the gap layer, and the free layer; a first upper surface located at the other end of the stacking direction; and a first side surface connecting the first lower surface and the first upper surface. The first side includes an inclined portion that is tilted relative to the stacking direction.

2. The magnetoresistive effect element according to claim 1, characterized in that, The first side surface includes a first portion and a second portion located between the first portion and the first upper surface. One of the first part and the second part is the inclined part.

3. The magnetoresistive effect element according to claim 2, characterized in that, The first part is the inclined portion. The angle formed by the first portion relative to the first lower surface is smaller than the angle formed by the second portion relative to the first lower surface.

4. The magnetoresistive effect element according to claim 2, characterized in that, The second part is the inclined portion. The angle between the second portion and the first lower surface is smaller than the angle between the first portion and the first lower surface.

5. The magnetoresistive effect element according to claim 4, characterized in that, The first portion is tilted relative to the stacking direction.

6. The magnetoresistive effect element according to claim 1, characterized in that, The magnetization fixing layer has: a second lower surface located at one end of the stacking direction, a second upper surface located at the other end of the stacking direction, and a second side surface connecting the second lower surface and the second upper surface. The second side includes a third portion that is inclined relative to the stacking direction.

7. The magnetoresistive effect element according to claim 6, characterized in that, The first side surface includes a first portion and a second portion located between the first portion and the first upper surface. The first part is the inclined portion. When the angle formed by the first part relative to the first lower surface is defined as the first angle, the angle formed by the second part relative to the first lower surface is defined as the second angle, and the angle formed by the third part relative to the second lower surface is defined as the third angle, the absolute value of the difference between the first angle and the third angle is less than the absolute value of the difference between the second angle and the third angle.

8. The magnetoresistive effect element according to claim 1, characterized in that, The planar shape of the inclined portion when viewed from the stacking direction is an annular shape.

9. A magnetic sensor, characterized in that, Equipped with multiple magnetic detection elements, The plurality of magnetic detection elements are magnetoresistive effect elements according to any one of claims 1 to 8.

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