Design method and manufacturing method of magnetic sensor

Abstract

The present invention provides a design method of a magnetic sensor that can easily cope with various design conditions. The magnetic sensor has a first and a second magnetoresistance effect element connected in series and a third and a fourth magnetoresistance effect element connected in series, the group of the first and the second magnetoresistance effect element and the group of the third and the fourth magnetoresistance effect element are connected in parallel, and the first and the fourth magnetoresistance effect element are connected to the power supply side. When designing the magnetic sensor, the magnetization directions of the first to the fourth magnetization fixed layers are rotated by the first to the fourth angles θ1 to θ4 relative to the prescribed reference angle, respectively, θ1 = θ3, θ2 = θ4, θ1 ≠ θ2, and θ1-θ2 are different. The relationship between the angle range of the magnetization direction of the first to the fourth magnetization free layer and the output range of the magnetic sensor that establishes a prescribed linear relationship with the output of each magnetic sensor is obtained, and a magnetic sensor that meets the required conditions of the angle range and the output range is selected from the plurality of magnetic sensors.

Description

Technical Field

[0001] The present application is based on and claims the benefit of priority from Japanese Patent Application No. 2021-7324 filed on January 20, 2021. The entirety of the application is incorporated herein by reference.

[0002] The present invention relates to a design method and a manufacturing method of a magnetic sensor, and in particular to a design method and a manufacturing method of a magnetic sensor using a magnetoresistive effect element. Background Art

[0003] A magnetic sensor using a magnetoresistance effect element is known. The magnetoresistance effect element has a magnetization fixed layer whose magnetization direction is fixed relative to an external magnetic field and a magnetization free layer whose magnetization direction rotates relative to the external magnetic field. Such a magnetic sensor is sometimes used to detect the direction of application of an external magnetic field. Japanese Patent Publication No. 2013-88232 and Japanese Patent Publication No. 2016-206075 disclose a magnetic sensor in which a plurality of magnetoresistance effect elements are connected by a bridge circuit. The output of the magnetic sensor changes approximately in a sinusoidal shape relative to the direction of application of the external magnetic field. Therefore, the magnetization direction of the magnetization fixed layer is determined to operate in an output region with relatively high linearity. Summary of the invention

[0004] Magnetic sensors are usually assembled into products or parts for use, but the positional relationship between the magnet that generates the external magnetic field and the magnetic sensor is usually determined by the design of the product or part. Therefore, the direction of the external magnetic field applied to the magnetization free layer of the magnetic sensor is also different for each product. In addition, the linearity or output range required for the magnetic sensor is also different for each product. Therefore, magnetic sensors need to be designed for individual products according to these conditions, and the rationalization of the design method is expected.

[0005] An object of the present invention is to provide a method for designing a magnetic sensor that can easily cope with various design conditions.

[0006] Technical solutions for solving technical problems

[0007] The present invention relates to a design method of a magnetic sensor, wherein the magnetic sensor comprises first and second magnetoresistance effect elements connected in series and third and fourth magnetoresistance effect elements connected in series, wherein the first and second magnetoresistance effect elements are connected in parallel with the third and fourth magnetoresistance effect elements, wherein the first and fourth magnetoresistance effect elements are connected to a power supply side, and wherein the first to fourth magnetoresistance effect elements respectively comprise first to fourth magnetization fixed layers whose magnetization directions are fixed and first to fourth magnetization free layers whose magnetization directions rotate according to an external magnetic field. The design method of the present invention comprises the steps of: obtaining a relationship between an angle range of the magnetization directions of the first to fourth magnetization free layers and an output range of the magnetic sensor, wherein the magnetization directions of the first to fourth magnetization fixed layers are rotated by first to fourth angles θ1 to θ4 relative to a predetermined reference angle, wherein θ1=θ3, θ2=θ4, θ1≠θ2, and θ1-θ2 are different, and the step of selecting a magnetic sensor that satisfies the required conditions of the angle range and the output range from the plurality of magnetic sensors.

[0008] According to the present invention, it is possible to provide a method for designing a magnetic sensor that can easily cope with various design conditions.

[0009] The above and other objects, features and advantages of the present application will become more apparent from the detailed description given below with reference to the accompanying drawings which illustrate the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1A , 1B This is a schematic diagram showing the operating principle of the magnetic sensor according to the first embodiment.

[0011] Figure 2A , 2B Yes means Figure 1A , 1B A conceptual diagram showing a schematic structure of a magnetoresistive element of a magnetic sensor shown in FIG.

[0012] Figure 3 This is a conceptual diagram showing the definition of linear error.

[0013] Figure 4 This is a flowchart showing an example of a method for designing a magnetic sensor.

[0014] Figure 5A , 5B : is a characteristic diagram of the magnetic sensor obtained in steps S2 and S3.

[0015] Fig. 6A , 6B is a characteristic diagram of the magnetic sensor obtained in step S4.

[0016] Fig. 7A , 7BIt is a schematic diagram showing a schematic structure of a magnetic sensor according to a second embodiment.

[0017] Fig. 8A , 8B It is a schematic diagram showing a schematic structure of a magnetic sensor according to a modified example.

[0018] Explanation of symbols:

[0019] 1…Magnetic sensor

[0020] 14A to 14D: first to fourth magnetization fixed layers

[0021] 16A to 16D ... first to fourth magnetization free layers

[0022] E1 to E4: first to fourth magnetoresistance effect elements DETAILED DESCRIPTION

[0023] (First Embodiment)

[0024] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. In the following description and the accompanying drawings, the Z direction coincides with the stacking direction of the stacked films of the magnetoresistive effect element. Figure 1A As shown, the magnetization directions of the magnetization fixed layer 14 and the magnetization free layer 16 and the direction of the external magnetic field are represented by an angle θ defined counterclockwise with three o'clock being 0°. θ=0° is sometimes referred to as a "predetermined reference angle".

[0025] Figure 1A , 1B is a schematic diagram showing the operating principle of the magnetic sensor 1. Figure 1A FIG. 1 shows a schematic circuit structure of the magnetic sensor 1. Figure 1B Represents the relationship between the magnetization direction of the magnetization free layer 16 and the output of the magnetic sensor 1. The magnetic sensor 1 has four magnetoresistance effect elements (hereinafter referred to as the first magnetoresistance effect element E1, the second magnetoresistance effect element E2, the third magnetoresistance effect element E3, and the fourth magnetoresistance effect element E4), and these magnetoresistance effect elements E1 to E4 are interconnected by a bridge circuit (Wheatstone bridge). The four magnetoresistance effect elements E1 to E4 are divided into two groups, and the magnetoresistance effect elements E1, E2 and the magnetoresistance effect elements E3, E4 of each group are connected in series. In addition, the group of magnetoresistance effect elements E1 and E2 and the group of magnetoresistance effect elements E3 and E4 are connected in parallel. One end of each of the group of magnetoresistance effect elements E1 and E2 and the group of E3 and E4 is connected to a power supply voltage V of a constant voltage. dd The magnetoresistive elements E1 and E4 are connected to the power supply voltage V ddside, and the magnetoresistance effect elements E2 and E3 are arranged on the GND side. In addition, the midpoint voltage V1 between the first magnetoresistance effect element E1 and the second magnetoresistance effect element E2, and the midpoint voltage V2 between the third magnetoresistance effect element E3 and the fourth magnetoresistance effect element E4 are selected, and the differential voltage V1-V2 is output as the output of the magnetic sensor 1. If the resistances of the first to fourth magnetoresistance effect elements E1 to E4 are set to R1 to R4, respectively, the midpoint voltages V1 and V2 are calculated as follows.

[0026]

[0027]

[0028] Figure 2A , 2B It is a conceptual diagram showing a schematic structure of the first to fourth magnetoresistance effect elements E1 to E4. Figure 2A 2 shows the film structures of the first to fourth magnetoresistance effect elements E1 to E4, Figure 2B A cross-sectional view showing the magnetization free layer 16, the inner magnetization fixed layer 14, and the outer magnetization fixed layer 12 as viewed from the Z direction. The first to fourth magnetoresistance effect elements E1 to E4 have the same structure. The first to fourth magnetoresistance effect elements E1 to E4 have a conventional spin valve type film structure. The first to fourth magnetoresistance effect elements E1 to E4 are stacked films including an antiferromagnetic layer 11, an outer magnetization fixed layer 12, a non-magnetic intermediate layer 13, an inner magnetization fixed layer 14, a spacer layer 15, and a magnetization free layer 16, and these layers 11 to 16 are stacked in sequence along the Z direction. The stacked film is sandwiched by a pair of electrode layers (not shown) in the Z direction, so that the induced current flows from the electrode layers to the stacked film along the Z direction.

[0029] The magnetization free layer 16 is a magnetic layer whose magnetization direction changes according to the external magnetic field, and can be formed of NiFe, for example. The outer magnetization fixed layer 12 is a ferromagnetic layer whose magnetization direction is fixed relative to the external magnetic field by exchange coupling with the antiferromagnetic layer 11. The antiferromagnetic layer 11 can be formed of PtMn, IrMn, NiMn, etc. The inner magnetization fixed layer 14 is a ferromagnetic layer sandwiched between the outer magnetization fixed layer 12 and the spacer layer 15, and is antiferromagnetically coupled to the outer magnetization fixed layer 12 via a non-magnetic intermediate layer 13 such as Ru and Rh. Therefore, the magnetization directions of the inner magnetization fixed layer 14 and the outer magnetization fixed layer 12 are both fixed relative to the external magnetic field, but their magnetization directions are set to be antiparallel to each other. The spacer layer 15 is a non-magnetic layer located between the magnetization free layer 16 and the inner magnetization fixed layer 14, which exerts a magnetoresistance effect. The spacer layer 15 is a non-magnetic conductive layer composed of a non-magnetic metal such as Cu or a tunnel barrier layer composed of a non-magnetic insulator such as Al2O3. When the spacer layer 15 is a non-magnetic conductive layer, the first to fourth magnetoresistance elements E1 to E4 function as giant magnetoresistance (GMR) elements, and when the spacer layer 15 is a tunnel barrier layer, the first to fourth magnetoresistance elements E1 to E4 function as tunnel magnetoresistance (TMR) elements. From the perspective of a large MR change rate and the ability to increase the output voltage of the bridge circuit, the first to fourth magnetoresistance elements E1 to E4 are more preferably TMR elements. In addition, in this specification, the inner magnetization fixed layer 14 is sometimes referred to as a magnetization fixed layer.

[0030] like Figure 2B As shown, when viewed from the Z direction, the magnetization free layer 16, the inner magnetization fixed layer 14 and the outer magnetization fixed layer 12, that is, the first magnetoresistance effect element E1, have a roughly circular cross-sectional shape. The arrows in the figure schematically indicate the magnetization directions of the respective films 16, 14, and 12. The magnetization direction of the magnetization free layer 16 rotates according to the direction of the external magnetic field. No bias magnetization is provided to apply a bias magnetic field to the magnetization free layer 16. Therefore, the magnetization direction of the magnetization free layer 16 is substantially consistent with the direction of the external magnetic field. The direction of the magnetic field applied to the magnetization free layer 16 is at an angle θ based on a specified reference angle (θ=0°). A and angle θ B The specific angle range is called the magnetic field detection angle range θ R . Magnetic field detection angle range θ R The magnetic sensing direction of the magnetic sensor 1 is determined and is limited by the product or component in which the magnetic sensor 1 is assembled. The magnetization direction of the magnetization free layer 16 is within the magnetic field detection angle range θ according to the direction of the external magnetic field. R The range of the magnetic field detection angle range θ R The central value θ cSince the relative angle between the magnetization direction of the inner magnetization fixed layer 14 and the magnetization direction of the magnetization free layer 16 changes, the resistance with respect to the induced current changes, so that the direction of the external magnetic field can be detected.

[0031] Refer again Figure 1A , the magnetization directions θ1 to θ4 of the inner magnetization fixed layers 14 of the first to fourth magnetoresistance effect elements E1 to E4 are oriented in the direction of the arrows in the figure. Therefore, if an external magnetic field is applied at an angle θ less than 90°, the resistance of the first and third magnetoresistance effect elements E1 and E3 is greater than the resistance of the second and fourth magnetoresistance effect elements E2 and E4. As a result, the midpoint voltage V1 is lower than the midpoint voltage V2, as shown in FIG. Figure 1B As shown, the differential voltage V1-V2 becomes negative. When an external magnetic field is applied at an angle θ greater than 90°, on the contrary, the midpoint voltage V1 is higher than the midpoint voltage V2, and the differential voltage V1-V2 becomes positive. By detecting the differential voltage V1-V2 of the midpoint voltages V1 and V2, a sensitivity twice as high as that of the case where the midpoint voltages V1 and V2 are detected can be obtained. In addition, in the case where the midpoint voltages V1 and V2 are offset, the influence of the offset can also be eliminated by detecting the differential voltage V1-V2. The differential voltage V1-V2 specifies the output range V of the magnetic sensor 1. R . Output range V R It is proportional to the sensitivity of the magnetic sensor 1 , but it is not necessarily absolute, and it varies depending on the product or component in which the magnetic sensor 1 is incorporated.

[0032] It is preferred that the output of the magnetic sensor 1 be as close to linear as possible. Here, the linear error E L Defined as a linearity indicator. Figure 3 As shown, within the specified angular range of the magnetization direction of the magnetization free layer 16, the actual waveform of the output of the magnetic sensor 1 is obtained. In order to define the linear error E L First, find the linear approximation line of the actual waveform. The linear approximation line can be found by, for example, the least square method, but is not limited to this. The maximum value of the output within the above angle range is set to dV H2 , set the minimum value to dV H1 The difference between the actual waveform and the linear approximation line is calculated at each angle θ in the above angle range, and the maximum value is set as ΔV max , then the linear error E is calculated as follows L .

[0033]

[0034] Linear error E L The ratio varies depending on the product or component in which the magnetic sensor 1 is incorporated, but is generally 5 to 10%. L=5%. Linear error E L It is not limited to equation (3), and any index that represents linearity can be used. L becomes a specified value (here E L =5%) is called the linear range θ L . Linear range θ L A predetermined linear relationship (here, E L =5%)) of the angular range of the magnetization direction of the first to fourth magnetization free layers 16A to 16D (angular range of the external magnetic field). Linear range θ L The required conditions vary depending on the product or component in which the magnetic sensor 1 is incorporated. Linear range θ L It is the angular range of the magnetization direction of the first to fourth magnetization free layers 16A to 16D in which the relationship with the output can be considered as roughly linear for the product or component assembled with the magnetic sensor 1. For example, in the autofocus mechanism of the camera, the magnet that generates the external magnetic field and the magnetic sensor 1 that detects the external magnetic field move relative to each other along the optical axis of the lens, but the relative movement distance is limited by the autofocus mechanism. Therefore, the direction of the external magnetic field applied to the magnetization free layer 16 of the magnetic sensor 1 is limited to a certain specified angular range, and the magnetic sensor 1 does not need to have a linear range exceeding it θ L .

[0035] Next, the design method of the magnetic sensor 1 is described. As described above, as the design conditions of the magnetic sensor 1, the output range V R and the linear range θ L are important, and this method provides a design approach that takes these into account. Figure 4 The general flow of the method is shown in . First, a plurality of magnetic sensors 1 are manufactured or prepared (step 1). The magnetic sensor 1 can be actually manufactured or manufactured by simulation. For the plurality of magnetic sensors 1, the magnetization directions of the first to fourth magnetization fixed layers 14A to 14D respectively form first to fourth angles θ1 to θ4 relative to a prescribed reference angle (θ=0°), and θ1=θ3, θ2=θ4, θ1≠θ2 (therefore, θ3≠θ4). However, θ1-θ2 are different from each other. Here, six types of magnetic sensors 1 are manufactured, and θ1=θ3=180° is set, and θ2 and θ4 are set to 0°, 30°, 60°, 90°, 120°, and 150°.

[0036] Next, the magnetization direction and output range V of the magnetization free layer 16 of the plurality of magnetic sensors 1 are obtained. R (Step 2). Figure 5AThe results of determining the relationship between the magnetization direction of the magnetization free layer 16 and the output (differential voltage V1-V2) of the magnetic sensor 1 for six types of magnetic sensors 1 are shown in FIG. The output is maximum when θ2=θ4=0° or 30°. As θ2 and θ4 increase, the output decreases, and the slope of the straight line portion of the graph decreases.

[0037] Next, for each magnetic sensor 1, a predetermined linear relationship (here, E L =5%) of the magnetization direction (linear range θ L ) and the output range V of the magnetic sensor 1 R relationship (step 3). Figure 5B An example of the result is shown in FIG. R At this time, the output range V can also be calculated based on the plotted points. R The approximate curve F can be obtained by, for example, the least square method. As can be seen from the figure, the linear range θ L and output range V R In a negative correlation. Even in the linear range θ L Small but large output range V R In the case of L Ratio output range V R In important cases, large θ2 and θ4 can be selected.

[0038] Next, a plurality of magnetic sensors 1 are selected to satisfy the linear range θ L and output range V R The magnetic sensor 1 of the required conditions (steps S5 and S6). Figure 5B , the selection can be done by a person or by a computer. L and output range V R Under the requirements of Figure 5B In the example shown in the figure, the required condition is defined as a predetermined rectangular region R. In the example shown in the figure, the magnetic sensor 1 with θ2=θ4=90° is selected. The intersection C of the horizontal line L1 that divides the region R in half along the longitudinal direction or the vertical line L2 that divides the region R in half along the transverse direction and the approximate curve can also be selected as the optimal θ2 and θ4. When the selection is performed by a computer, the magnetization direction and output range V of the magnetization free layer 16 of the plurality of magnetic sensors 1 are input. R The relationship ( Figure 5A ), linear range θ L and output range V RThe CPU calculates θ2, θ4 or the range of θ2, θ4 that meets the requirements.

[0039] It is preferable to use the magnetic sensor 1 in a region where the output linearity is good. However, as described above, in a specific magnetic field detection angle range θ R For example, if an external magnetic field is applied within a certain range, Figure 5A As shown in area A, in the magnetic field detection angle range θ R In the case of an angle range of 120 to 240° with 180° as the center, the measurement accuracy decreases because the magnetic sensor 1 uses a region with poor linearity. Fig. 6A As shown in area A, if the output at θ = 180° becomes the output range V R Therefore, before selecting the magnetic sensor 1, it is preferred to correct Figure 5A Specifically, the relative relationship between the first to fourth angles θ1 to θ4 is set constant, and the first to fourth angles θ1 to θ4 are changed so as to satisfy (θ1+θ2) / 2=θ c The relative relationship between the first to fourth angles θ1 to θ4 is constant, which means that the difference between θ1 and θ2, the difference between θ1 and θ3, and the difference between θ1 and θ4 are all constant. Figure 5A In the example shown, θ c =180°. Fig. 6A : represents the relationship between the magnetization direction of the magnetization free layer 16 and the output of the magnetic sensor 1 obtained by this operation, Figure 6B Indicates the linear range θ L and output range V R relationship. Fig. 6A The curves are Figure 5A The corresponding curve is moved parallel to the curve, and the shape of the curve itself is Figure 5A and Fig. 6A Therefore, Figure 6B and Figure 5B The selection of magnetic sensor 1 can be based on Figure 5B The chart can also be based on Figure 6B However, by Figure 6B By selecting the magnetic sensor 1 in the graph, it is possible to simultaneously obtain the optimal values ​​of the first to fourth angles θ1 to θ4.

[0040] Step S4 produces the same effect as rotating the magnetic sensor 1 as a whole. However, it is sometimes difficult to rotate the magnetic sensor 1. The magnetization direction of the magnetization fixed layer 14 can be easily adjusted according to the magnetization direction, so according to this embodiment, a design method of the magnetic sensor 1 with high versatility can be provided. In addition, the magnetization fixed layer 14 with a circular cross-section has no directionality and can be magnetized in the same way at any angle. Similarly, the magnetization free layer 16 with a circular cross-section has no directionality (no shape anisotropy) and rotates in the same way regardless of the direction of application of the external magnetic field. That is, because the magnetoresistive effect element itself has no directionality caused by the shape, the magnetization direction of the magnetization fixed layer 14 can be changed in various ways according to the application. In this way, it can be said that the present embodiment has a high affinity with circular magnetoresistive effect elements.

[0041] Here, a method for manufacturing the magnetic sensor 1 designed by the above method is briefly described. The method for manufacturing the magnetic sensor 1 includes a step of forming the first to fourth magnetoresistance effect elements E1 to E4. In this step, first, first to fourth initial magnetoresistance effect elements that will later become the first to fourth magnetoresistance effect elements E1 to E4 are formed. Each of the first to fourth initial magnetoresistance effect elements includes the first to fourth initial magnetization fixed layers that will later become the inner magnetization fixed layers 14.

[0042] Next, using laser light and an external magnetic field of a predetermined direction, the magnetization directions of the first to fourth initial magnetization fixed layers are fixed to the predetermined directions described above. For example, in the first and third initial magnetoresistive effect elements that will later constitute the first and third magnetoresistive effect elements E1 and E3, the external magnetic field of the first magnetization direction θ1 and θ3 is applied while the laser light is irradiated to the first and third initial magnetoresistive effect elements. When the laser light irradiation is completed, the magnetization directions of the first and third initial magnetization fixed layers are fixed to the first magnetization directions θ1 and θ3. Thus, the first and third initial magnetization fixed layers become the first and third magnetization fixed layers, and the first and third initial magnetoresistive effect elements become the first and third magnetoresistive effect elements E1 and E3. In addition, in the second and fourth initial magnetoresistive effect elements that will later constitute the second and fourth magnetoresistive effect elements E2 and E4, by setting the direction of the external magnetic field to the second magnetization direction θ2 and θ4, the magnetization directions of the initial magnetization fixed layers of the second and fourth initial magnetoresistive effect elements can be fixed to the second magnetization directions θ2 and θ4. In this way, the first to fourth magnetoresistive effect elements E1 to E4 are formed.

[0043] The method of fixing the direction of magnetization of the magnetization fixed layer (initial magnetization fixed layer) using laser light may also be so-called laser annealing.

[0044] (Second Embodiment)

[0045] This embodiment is the same as the first embodiment except that a plurality of magnetoresistance effect elements are connected by a half bridge instead of a Wheatstone bridge. The magnetic sensor 1 has a first magnetoresistance effect element E1 and a second magnetoresistance effect element E2 connected in a row, and the first magnetoresistance effect element E1 has a first magnetization fixed layer 14A whose magnetization direction is fixed and a first magnetization free layer 16A whose magnetization direction rotates according to an external magnetic field. The second magnetoresistance effect element E2 has a second magnetization fixed layer 14B whose magnetization direction is fixed and a second magnetization free layer 16B whose magnetization direction rotates according to an external magnetic field.

[0046] In this embodiment, as in the first embodiment, Figure 4 The steps shown are used to design the magnetic sensor 1. Specifically, a plurality of magnetic sensors 1 are manufactured, wherein the magnetization direction of the first magnetization fixed layer 16A forms a first angle θ1 relative to a predetermined reference angle (here, θ=0°), and the magnetization direction of the second magnetization fixed layer 16B forms a second angle θ2 relative to the predetermined reference angle, and θ1-θ2 are different (step 1). The magnetic sensor 1 can be manufactured in practice or by simulation. Next, the magnetization direction and output range V of the magnetization free layer 16 are calculated for the plurality of magnetic sensors 1. R Next, for each magnetic sensor 1, the angular range of the magnetization direction (linear range θ) within which a predetermined linear relationship is established between the magnetization directions of the first and second magnetization free layers 16A, 16B and the output of each magnetic sensor 1 is obtained. L ) and the output of the magnetic sensor 1 (step 3). Next, select from a plurality of magnetic sensors 1 that satisfy the angle range (linear range θ L ) and output range V R Before selecting the magnetic sensor 1, the first angle θ1 and the second angle θ2 may be changed so that (θ1+θ2) / 2=θ2 is satisfied without changing θ1-θ2. c (Step 4). In addition, the magnetic sensor 1 designed by the method of this embodiment can be manufactured by the method described in the first embodiment.

[0047] The present invention has been described above by way of embodiments, but the present invention is not limited to these embodiments and can be modified in various ways. Fig. 8AAs shown, the magnetic sensor 1 may also have a bias magnet 18 for applying a bias magnetic field to the magnetization free layer 16. In the figure, the black arrow is the direction of application of the external magnetic field, and the white arrow is the direction of application of the bias magnetic field. The direction of the external magnetic field is constant, and only the intensity changes. A pair of bias magnets 18 are arranged on both sides of each of the magnetoresistive effect elements E1 to E4, and a bias magnetic field is applied in a direction orthogonal to the magnetization direction of the magnetization fixed layer 14. A composite magnetic field of the bias magnetic field and the external magnetic field is applied to the magnetization free layer 16. Because the resistance of the magnetoresistive effect elements E1 to E4 changes according to the direction of the composite magnetic field, the intensity of the external magnetic field can be calculated based on the output of the magnetic sensor 1. Or, as Figure 8B As shown, the magnetoresistance effect elements E1 to E4 are formed into a strip shape that is long in one direction. Even if the magnetization direction of the magnetization free layer 16 in the absence of a magnetic field is oriented in the long-side direction due to shape anisotropy, the same effect can be obtained.

[0048] In addition, in this embodiment, the magnetic sensor 1 is driven by a constant voltage, but it can also be driven by a constant current. In the constant current drive, the total value of the current input to the first magnetoresistance effect element E1 and the fourth magnetoresistance effect element E4 (first embodiment) or the current input to the first magnetoresistance effect element E1 (second embodiment) is maintained constant. Details are omitted, but even in this case, the same characteristics as those shown in Figures 5 and 6 are obtained, and the magnetic sensor 1 can be designed according to the above method.

[0049] While several preferred embodiments of the present invention have been shown and described in detail, it will be appreciated that various changes and modifications may be made without departing from the spirit or scope of the appended claims.

Claims

1. A method for designing a magnetic sensor, wherein: The magnetic sensor comprises a group of first and second magnetoresistance effect elements connected in series and a group of third and fourth magnetoresistance effect elements connected in series, the group of the first and second magnetoresistance effect elements and the group of the third and fourth magnetoresistance effect elements are connected in parallel, the first and fourth magnetoresistance effect elements are connected to a power supply side, the first to fourth magnetoresistance effect elements respectively comprise first to fourth magnetization fixed layers whose magnetization directions are fixed and first to fourth magnetization free layers whose magnetization directions rotate according to an external magnetic field, The design method has the following features: A step of preparing a plurality of magnetic sensors in which the magnetization directions of the first to fourth magnetization fixed layers form first to fourth angles θ1 to θ4 relative to a predetermined reference angle, θ1=θ3, θ2=θ4, θ1≠θ2, and θ1-θ2 are different; A step of obtaining a relationship between an angle range and an output range of each magnetic sensor, wherein the angle range is an angle range of magnetization directions of first to fourth magnetization free layers that establishes a predetermined linear relationship with the output of the magnetic sensor; and A step of selecting a magnetic sensor that satisfies the required conditions of the angle range and the output range from the plurality of magnetic sensors.

2. The design method according to claim 1, wherein: have: Before selecting the magnetic sensor, the relative relationship between the first to fourth angles θ1 to θ4 is set constant, and the first to fourth angles θ1 to θ4 are changed to satisfy (θ1+θ2) / 2=θ c The relationship between the steps, where θ c is a middle value of the magnetic field detection angle range of the magnetic sensor relative to the predetermined reference angle.

3. The design method according to claim 1, wherein: The first to fourth magnetization fixed layers and the first to fourth magnetization free layers have circular cross sections.

4. A method for manufacturing a magnetic sensor, wherein: The magnetic sensor is designed by the design method described in any one of claims 1 to 3. The manufacturing method comprises the steps of forming the first to fourth magnetoresistance effect elements. The steps of forming the first to fourth magnetoresistance effect elements include: forming first to fourth initial magnetoresistance effect elements, the first to fourth initial magnetoresistance effect elements including first to fourth initial magnetization fixed layers which will later become the first to fourth magnetization fixed layers, respectively; and A step of fixing the magnetization directions of the first to fourth initial magnetization fixed layers using laser light and an external magnetic field.

5. A method for designing a magnetic sensor, wherein: The magnetic sensor includes a first magnetoresistance effect element and a second magnetoresistance effect element connected in series, the first magnetoresistance effect element including a first magnetization fixed layer whose magnetization direction is fixed and a first magnetization free layer whose magnetization direction rotates according to an external magnetic field, and the second magnetoresistance effect element including a second magnetization fixed layer whose magnetization direction is fixed and a second magnetization free layer whose magnetization direction rotates according to an external magnetic field, The design method has the following features: A step of preparing a plurality of magnetic sensors in which the magnetization direction of the first magnetization fixed layer forms a first angle θ1 relative to a predetermined reference angle, the magnetization direction of the second magnetization fixed layer forms a second angle θ2 relative to the predetermined reference angle, θ1≠θ2, and θ1-θ2 are different; A step of obtaining a relationship between an angle range and an output range of each magnetic sensor, wherein the angle range is an angle range of magnetization directions of the first and second magnetization free layers that establishes a predetermined linear relationship with the output of the magnetic sensor; and A step of selecting a magnetic sensor that satisfies the required conditions of the angle range and the output range from the plurality of magnetic sensors.

6. The design method according to claim 5, wherein: have: Before selecting the magnetic sensor, the relative relationship between the first angle θ1 and the second angle θ2 is set to be constant, and the first angle θ1 and the second angle θ2 are changed to satisfy (θ1+θ2) / 2=θ c The relationship between the steps, where θ c is a middle value of the magnetic field detection angle range of the magnetic sensor relative to the predetermined reference angle.

7. The design method according to claim 5, wherein: The first and second magnetization fixed layers and the first and second magnetization free layers have circular cross sections.

8. A method for manufacturing a magnetic sensor, wherein: The magnetic sensor is designed by the design method described in any one of claims 5 to 7, The manufacturing method comprises the steps of forming the first and second magnetoresistance effect elements. The step of forming the first and second magnetoresistance effect elements includes: forming first and second initial magnetoresistance effect elements, the first and second initial magnetoresistance effect elements including first and second initial magnetization fixed layers which will later become the first and second magnetization fixed layers, respectively; and A step of fixing the magnetization directions of the first to second initial magnetization fixed layers using laser light and an external magnetic field.

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