JP2020073909A - Magnetic field detection device - Google Patents

Abstract

To provide a magnetic field detection device having more superior magnetic field detection performance.SOLUTION: A magnetic field detection device has a first soft magnetic material, a second soft magnetic material and a magnetic detection element. The first soft magnetic material and the second soft magnetic material are spread along a first surface including a first direction and a second direction orthogonal to the first direction, and arranged oppositely in a third direction orthogonal to both of the first direction and the second direction. The magnetic detection element is provided between the first soft magnetic material and the second soft magnetic material in the third direction.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to a magnetic field detection device that detects a magnetic field using a magnetic detection element.

  As a magnetic field detection device (magnetic field detection device) that detects an external magnetic field, a device using a Hall element or a magnetoresistive effect element is known (see, for example, Patent Document 1).

International Publication No. 2008/146809

  By the way, in recent years, improvement of magnetic field detection performance has been demanded. Therefore, it is desirable to provide a magnetic field detection device having more excellent magnetic field detection performance.

  A magnetic field detection device as an embodiment of the present invention includes a first soft magnetic material, a second soft magnetic material, and a magnetic detection element. The first soft magnetic material and the second soft magnetic material spread along the first surface including both the first direction and the second direction orthogonal to the first direction, and the first direction. And in a third direction orthogonal to both the second direction and the second direction. The magnetic detection element is provided between the first soft magnetic body and the second soft magnetic body in the third direction.

  In the magnetic field detection device as one embodiment of the present invention, the first soft magnetic body and the second soft magnetic body are provided so as to sandwich the magnetic detection element in the third direction. Therefore, for the external magnetic field component in the third direction, both the first soft magnetic body and the second soft magnetic body behave as magnetic yokes. On the other hand, both the first soft magnetic material and the second soft magnetic material act as a magnetic shield for the external magnetic field component along the first surface.

In the magnetic field detection device as one embodiment of the present invention, at least one of the first soft magnetic material and the second soft magnetic material has a dimension in the first direction as LX and a dimension in the second direction. When LY is LY, it is desirable that the following conditional expression (1) is satisfied.
1 ≦ LX / LY ≦ 4 (1)
Since the limiting magnetic field strength for the magnetic field in the second direction in at least one of the first soft magnetic material and the second soft magnetic material increases, the magnetic field for the magnetic field in the second direction along the first surface increases. This is because the effective shield effect is further improved. The limiting magnetic field strength referred to here is the strength of the external magnetic field that causes the magnetization of the magnetic material (in this case, the first soft magnetic material and the second soft magnetic material) to be saturated.

In the magnetic field detection device as one embodiment of the present invention, the magnetic detection element may be a magnetoresistive effect element. Further, the first soft magnetic body includes a first facing surface facing the second soft magnetic body, the second soft magnetic body includes a second facing surface facing the first soft magnetic body, The first angle formed by the first straight line connecting the magnetic detection element and the edge of the first facing surface with respect to the first surface is 45 ° or less, and the magnetic detection element with the second surface with respect to the first surface The second angle formed by the second straight line connecting to the edge of the facing surface is preferably 45 ° or less. In that case, in the third direction, the position of the edge of the first facing surface and the position of the edge of the second facing surface match, and the following conditional expression (2) is satisfied. Good.
L ≧ D / 2 (2)
However, L is the distance between the edge of the first facing surface and the edge of the magnetic detection element in the direction along the first surface, and D is the distance between the first facing surface and the second facing surface. It is a distance.

  In the magnetic field detection device as one embodiment of the present invention, at least one of the first facing surface and the second facing surface may have one or more protrusions. In that case, it is preferable that a part of the protrusion be substantially parallel to the first surface and occupy a part of a layer including the magnetic detection element.

  According to the magnetic field detection device as one embodiment of the present invention, while the first soft magnetic material and the second soft magnetic material exert the shield effect against the external magnetic field component along the first surface, Thus, the external magnetic field component in the third direction is enhanced. Therefore, high magnetic field detection performance can be exhibited for the external magnetic field component in the third direction.

It is a schematic perspective view showing the whole structure of the magnetic field detection apparatus as the 1st Embodiment of this invention. It is sectional drawing showing the cross-sectional structure of the magnetic field detection apparatus shown in FIG. It is an expanded sectional view showing the cross-sectional structure of the magnetic detection element shown in FIG. FIG. 3 is a circuit diagram showing an example of a signal detection circuit mounted on the magnetic field detection device shown in FIG. 1. It is a schematic perspective view showing the whole structure of the magnetic field detection apparatus as the 2nd Embodiment of this invention. FIG. 4B is a cross-sectional view illustrating a cross-sectional configuration of the magnetic field detection device illustrated in FIG. 4A. FIG. 9 is a perspective view showing a modified example (first modified example) of the magnetic field detection device shown in FIGS. 4A and 4B. FIG. 5B is a cross-sectional view illustrating a cross-sectional configuration of the magnetic field detection device illustrated in FIG. 5A. It is sectional drawing showing the modification (2nd modification) of the magnetic field detection apparatus shown to FIG. 4A and FIG. 4B. It is sectional drawing showing the modification (3rd modification) of the magnetic field detection apparatus shown to FIG. 4A and FIG. 4B. It is sectional drawing showing the modification (4th modification) of the magnetic field detection apparatus shown to FIG. 4A and FIG. 4B. It is a characteristic view showing the magnetic field strength distribution in the magnetic field detection apparatus of Experimental example 1-1. It is a characteristic view showing the magnetic field strength distribution in the magnetic field detection apparatus of Experimental example 1-2. It is a characteristic view showing the magnetic field strength distribution in the magnetic field detection apparatus of Experimental example 1-3. It is a characteristic view showing the magnetic field strength distribution in the magnetic field detection apparatus of Experimental example 1-4. It is a characteristic view showing the magnetic field strength distribution in the magnetic field detection apparatus of Experimental example 1-5. It is a characteristic view showing the magnetic field strength distribution in the magnetic field detection apparatus of Experimental example 2-1. It is a characteristic view showing the magnetic field strength distribution in the magnetic field detection apparatus of Experimental example 2-2. It is a characteristic view showing the critical magnetic field strength in the magnetic field detection apparatus of Experimental example 3-1 to 3-8. It is a schematic diagram showing the 1st modification of the plane shape of a soft magnetic body. It is a schematic diagram showing the 2nd modification of the plane shape of a soft magnetic body. It is a schematic diagram showing the 3rd modification of the plane shape of a soft magnetic body. It is a schematic diagram showing the 4th modification of the plane shape of a soft magnetic body. It is sectional drawing showing the magnetic field detection apparatus as a 5th modification. It is sectional drawing showing the magnetic field detection apparatus as a 6th modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.
1. First Embodiment An example of a magnetic field detection device including a pair of soft magnetic layers each having a flat surface.
2. 2. Second Embodiment and its Modifications 2.1 An example of a magnetic field detection device including a pair of soft magnetic layers each having a convex portion provided on a flat surface.
2.2 First modified example (an example of a magnetic field detection device including a plurality of magnetic detection elements sandwiched between a pair of soft magnetic layers).
2.3 Second modification (example in which a convex portion is formed only on one soft magnetic layer).
2.4 Third Modified Example (example in which the soft magnetic layer has convex portions of other shapes).
2.5 Fourth Modified Example (an example in which convex portions are arranged at different pitches in a pair of soft magnetic layers).
3. Experimental example 4. Other variants

<1. First Embodiment>
[Configuration of magnetic field detection device 1]
First, the configuration of the magnetic field detection device 1 according to the first embodiment of the present invention will be described with reference to FIGS. 1A, 1B, 2 and the like. FIG. 1A is a perspective view showing an example of the overall configuration of the magnetic field detection device 1. FIG. 1B shows a cross-sectional configuration example of the magnetic field detection device 1 in the arrow direction along the line IB-IB shown in FIG. 1A. FIG. 2 shows an example of a sectional configuration of the magnetic detection element 20 shown in FIGS. 1A and 1B.

  The magnetic field detection device 1 is a device that detects the presence, direction, strength, and the like of an external magnetic field reaching itself, and is mounted on, for example, an electronic compass. The magnetic field detection device 1 includes, for example, a pair of soft magnetic layers 11 and 12 arranged to face each other in the Z-axis direction, and a magnetic detection element 20 provided between the soft magnetic layer 11 and the soft magnetic layer 12 in the Z-axis direction. It has and. The magnetic field detection device 1 further has leads 21 and 22 for flowing a sense current to the magnetic detection element 20. Note that, in FIG. 2, illustration of the leads 21 and 22 is omitted.

(Soft magnetic layers 11 and 12)
Each of the soft magnetic layers 11 and 12 extends along the XY plane orthogonal to the Z-axis direction. The soft magnetic layers 11 and 12 are made of, for example, a soft magnetic metal material having a high saturation magnetic flux density such as nickel iron alloy (NiFe). As shown in FIG. 1A, the soft magnetic layers 11 and 12 have a rectangular planar shape in the XY plane, and when the dimension in the X-axis direction is LX and the dimension in the Y-axis direction is LY, the dimension with respect to the dimension LY is set. It is desirable that the LX ratio (LX / LY) be 1 or more and 4 or less. That is, it is desirable to satisfy the following conditional expression (1).
1 ≦ LX / LY ≦ 4 (1)
In that case, the soft magnetic layers 11 and 12 function as a magnetic shield that more effectively prevents the external magnetic field in the Y-axis direction from reaching the magnetic detection element 20. Therefore, when using this magnetic field detection device 1, it is preferable to make the Y-axis direction coincide with the direction of an unnecessary external magnetic field component in a direction different from the external magnetic field component to be detected. This is because by setting the attitude (direction) of the magnetic field detection device 1 in this way, the magnetic detection element 20 can be magnetically shielded from unnecessary external magnetic field components. The soft magnetic layer 11 includes a flat surface 11S facing the soft magnetic layer 12, and the one soft magnetic layer 12 includes a flat surface 12S facing the soft magnetic layer 11. Both the flat surface 11S and the flat surface 12S are substantially parallel to the XY plane.

(Magnetic detection element 20)
As the magnetic detection element 20, for example, a magnetoresistive effect (MR) element that exhibits a resistance change according to the direction and strength of an external magnetic field is used. The magnetic detection element 20 is, for example, as shown in FIG. 2, a CPP (Current Perpendicular to Plane) type MR element having a spin valve structure in which a plurality of functional films including a magnetic layer are stacked, and the sense current itself is Flowing in the stacking direction. Specifically, as shown in FIG. 2, the magnetic detection element 20 includes an antiferromagnetic layer 31, a magnetization pinned layer 32 having a magnetization pinned in a certain direction, and an intermediate layer not expressing a specific magnetization direction. 33 and a magnetization free layer 34 having a magnetization that changes in accordance with an external magnetic field are sequentially laminated. Each of the antiferromagnetic layer 31, the magnetization pinned layer 32, the intermediate layer 33, and the magnetization free layer 34 may have a single-layer structure or a multilayer structure composed of a plurality of layers. In such an MR element, the resistance changes in accordance with the change in the magnetic flux along the film surface orthogonal to the stacking direction. In the magnetic field detection device 1, when the stacking direction of the magnetic detection elements 20 is set to the Z-axis direction, in order to cause the resistance change according to the change of the magnetic flux F (FIG. 1B) in the Z-axis direction, the second As described in the embodiments and subsequent embodiments, a convex portion or the like which can bend the direction of the magnetic flux F in the vicinity of the magnetic detection element 20 so as to be along the XY in-plane direction which is the magnetic sensitive direction of the magnetic detection element 20 is provided. preferable.

  The antiferromagnetic layer 31 is made of an antiferromagnetic material such as a platinum manganese alloy (PtMn) or an iridium manganese alloy (IrMn). The antiferromagnetic layer 31 is in a state in which, for example, the spin magnetic moment substantially in the same direction as the magnetization direction of the adjacent magnetization pinned layer 32 and the spin magnetic moment in the opposite direction to the magnetization direction are completely canceled each other. It acts so as to fix the magnetization direction of the pinned layer 32 in a fixed direction.

  The magnetization fixed layer 32 is made of a ferromagnetic material such as cobalt (Co), cobalt iron alloy (CoFe), or cobalt iron boron alloy (CoFeB).

  When the magnetic detection element 20 is a magnetic tunneling junction (MTJ: magnetic tunneling junction) element, the intermediate layer 33 is a non-magnetic tunnel barrier layer made of, for example, magnesium oxide (MgO), and a tunneling current based on quantum mechanics passes therethrough. It is as thin as possible. The tunnel barrier layer made of MgO is obtained by, for example, a sputtering process using a target made of MgO, an oxidation process of a thin film of magnesium (Mg), or a reactive sputtering process of sputtering magnesium in an oxygen atmosphere. .. In addition to MgO, the intermediate layer 33 can be formed using an oxide or a nitride of aluminum (Al), tantalum (Ta), or hafnium (Hf). When the magnetic detection element 20 is, for example, a GMR (Giant Magnetoresistive) element, the intermediate layer 33 is made of a nonmagnetic highly conductive material such as copper (Cu), ruthenium (Ru) or gold (Au).

  The magnetization free layer 34 is a soft ferromagnetic layer, and has, for example, an easy axis of magnetization substantially orthogonal to the magnetization direction of the magnetization pinned layer 32. The magnetization free layer 34 is made of, for example, a cobalt iron alloy (CoFe), a nickel iron alloy (NiFe), or cobalt iron boron (CoFeB).

(Leads 21, 22)
The lead 21 extends in the XY plane so as to come into contact with one end surface (for example, the magnetization free layer 34) of the magnetic detection element 20, and the lead 22 comes into contact with the other end surface (for example, the antiferromagnetic layer 31) of the magnetic detection element 20. It extends in the XY plane. The leads 21 and 22 are formed of a highly conductive non-magnetic material such as copper or aluminum (Al).

(Arrangement position of the magnetic detection element 20)
As shown in FIG. 1B, in the magnetic field detection device 1, straight lines LA1 and LA2 connecting the magnetic detection element 20 to the flat surface 11S and the edges 11T1 and 11T2 located at both ends of the flat surface 11S in the Y-axis direction are formed. Both angles A1 and A2 are preferably 45 ° or less. Further, the angles B1 and B2 formed by the straight lines LB1 and LB2 connecting the magnetic detection element 20 and the edges 12T1 and 12T2 located at both ends of the flat surface 12S in the Y-axis direction with respect to the flat surface 12S are both 45 ° or less. Good. That is, the magnetic detection element 20 is preferably arranged in the space surrounded by the four straight lines LA1, LA2, LB1, LB2 shown in FIG. 1B. This is because the magnetic detection element 20 is sufficiently shielded from the external magnetic field component in the Y-axis direction by the soft magnetic layers 11 and 12. As shown in FIG. 1B, the edge 11T1 is a portion where the end surface 11E1 and the flat surface 11S intersect, and the edge 11T2 is a portion where the end surface 11E2 and the flat surface 11S intersect. Similarly, the edge 12T1 is a portion where the end surface 12E1 and the flat surface 12S intersect, and the edge 12T2 is a portion where the end surface 12E2 and the flat surface 12S intersect. Each of the end edges 11T1, 11T2, 12T1 and 12T2 extends linearly in the X-axis direction.

  As shown in FIG. 1B, when the positions of the edges 11T1 and 11T2 of the soft magnetic layer 11 and the positions of the edges 12T1 and 12T2 of the soft magnetic layer 12 substantially coincide with each other in the Z-axis direction, It is desirable to satisfy the following conditional expression (2). Also in this case, the magnetic detection element 20 is sufficiently shielded from the external magnetic field component in the Y-axis direction by the soft magnetic layers 11 and 12.

L ≧ D / 2 (2)
However, L is the distance between the edges 11T1 and 11T2 and the edge of the magnetic detection element 20 in the Y-axis direction, and D is the distance between the flat surface 11S and the flat surface 12S (see FIG. 1B).

(Signal detection circuit)
The magnetic field detection device 1 has, for example, the signal detection circuit shown in FIG. This signal detection circuit includes, for example, a voltage application unit 101, a magnetic detection element 20, a resistance change detection unit 102, and a signal processing unit 103. A voltage application unit 101 and a resistance change detection unit 102 are connected to the magnetic detection element 20. The signal processing unit 103 is connected to the resistance change detection unit 102.

[Operation and Effect of Magnetic Field Detector 1]
In the magnetic field detection device 1, the signal detection circuit described above can provide an output according to the external magnetic field reaching the magnetic field detection device 1. Specifically, in the above signal detection circuit, by applying a predetermined voltage between the lead 21 and the lead 22 by the voltage application unit 101, a sense corresponding to the electric resistance of the magnetic detection element 20 at that time. An electric current flows. The electric resistance of the magnetic detection element 20 changes depending on the magnetization state of the magnetic detection element 20, that is, the magnetization direction of the magnetization free layer 34 with respect to the magnetization direction of the magnetization fixed layer 32. The sense current flowing through the magnetic detection element 20 is detected by the resistance change detection unit 102, and the resistance change detection unit 102 outputs a signal to the signal processing unit 103. Further, the signal processing unit 103 generates a signal based on the output from the resistance change detection unit 102 and outputs the signal to the outside. As a result, an output corresponding to the external magnetic field reaching the magnetic field detection device 1 is obtained from the signal detection circuit.

  In the magnetic field detection device 1 of the present embodiment, a pair of soft magnetic layer 11 and soft magnetic layer 12 are arranged so as to face each other so as to sandwich the magnetic detection element 20 in the Z-axis direction. Therefore, both the soft magnetic layer 11 and the soft magnetic layer 12 behave as magnetic yokes with respect to the external magnetic field component in the Z-axis direction. On the other hand, for the external magnetic field component in the Y-axis direction, both the soft magnetic layer 11 and the soft magnetic layer 12 behave as magnetic shields. That is, according to the magnetic field detection device 1, the soft magnetic layer 11 and the soft magnetic layer 12 exert the shield effect on the external magnetic field component in the Y-axis direction, while exhibiting the shield effect on the external magnetic field component in the Z-axis direction. It will be strengthened. Therefore, high magnetic field detection performance can be exhibited for the external magnetic field component in the Z-axis direction.

<2. Second Embodiment>
[2.1 Magnetic field detector 2]
Next, with reference to FIGS. 4A and 4B, the configuration of the magnetic field detection device 2 according to the second embodiment of the present invention will be described. FIG. 4A is a perspective view showing an example of the overall configuration of the magnetic field detection device 2. FIG. 4B shows a configuration example of the YZ cross section of the magnetic field detection device 2 in the arrow direction along the line IVB-IVB shown in FIG. 4A.

  In the magnetic field detection device 2 of the present embodiment, the convex portion 11P is provided on the flat surface 11S of the soft magnetic layer 11, and the convex portion 12P is provided on the flat surface 12S of the soft magnetic layer 12. Furthermore, the stacking direction of the MR element as the magnetic detection element 20 is set to the Z-axis direction, the lead 21 is connected to the upper surface of the magnetic detection element 20, and the lead 22 is connected to the lower surface of the magnetic detection element 20. Except for these points, the magnetic field detection device 2 has substantially the same configuration as the magnetic field detection device 1 in the first embodiment described above.

  As shown in FIGS. 4A and 4B, the convex portion 11P is erected on the flat surface 11S so as to project toward the flat surface 12S. On the other hand, the convex portion 12P is erected on the flat surface 12S so as to project toward the opposing flat surface 11S. However, the convex portion 11P and the convex portion 12P are provided at different positions in the XY plane. Further, the magnetic detection element 20 is arranged at a position sandwiched between the convex portion 11P and the convex portion 12P in the XY plane (here, in the Y-axis direction).

  As described above, in the magnetic field detection device 2, since the soft magnetic layers 11 and 12 are provided with the convex portions 11P and 12P and the magnetic detection element 20 is provided between them, the magnetic flux F due to the external magnetic field component in the Z-axis direction is generated. It can be concentrated on the magnetic detection element 20. At that time, the direction of the magnetic flux F in the vicinity of the magnetic detection element 20 can be bent along the XY in-plane direction, which is the magnetically sensitive direction of the magnetic detection element 20. Therefore, the extending directions of the soft magnetic layers 11 and 12 and the extending directions of the respective layers of the magnetic detection element 20 can be substantially matched with each other, which facilitates manufacturing.

[2.2 Magnetic Field Detector 2A]
Next, with reference to FIG. 5A and FIG. 5B, a magnetic field detection device 2A as a first modification example of the second embodiment will be described. FIG. 5A is a perspective view showing an example of the overall configuration of the magnetic field detection device 2A. FIG. 5B shows an example of a cross-sectional configuration of the magnetic field detection device 2A in the arrow direction along the line VB-VB shown in FIG. 5A.

  The magnetic field detection device 2A is provided with a plurality of magnetic detection elements 20 sandwiched between a pair of soft magnetic layers 11 and 12. Although FIG. 5A illustrates six magnetic detection elements 20 arranged in two rows and three columns, the number of the plurality of magnetic detection elements 20 and the arrangement form thereof are not limited thereto. However, it is preferable that the plurality of magnetic detection elements 20 are all provided in the same layer. The plurality of magnetic detection elements 20 are connected in series as a whole by a plurality of leads 23 and a plurality of leads 24, for example. Further, the convex portion 11P or the convex portion 12P is provided between the adjacent magnetic detection elements 20 (FIG. 5B). By doing so, the magnetic field detection device 2A can increase the overall output as compared with the magnetic field detection device 2. In addition, in FIG. 5A, in order to avoid complexity, illustration of the convex portion 11P and the convex portion 12P is omitted.

[2.3 Magnetic field detector 2B]
Next, with reference to FIG. 6, a magnetic field detection device 2B as a second modification of the second embodiment will be described. FIG. 6 is a sectional view showing an example of the overall configuration of the magnetic field detection device 2B. In the magnetic field detecting device 2A, the soft magnetic layer 11 is provided with the convex portion 11P and the soft magnetic layer 12 is provided with the convex portion 12P. The convex portion 11P is provided. The convex portion 12P may be provided only on the soft magnetic layer 12. Even in this case. The magnetic flux of the external magnetic field component in the Z-axis direction can be focused and guided to the magnetic detection element 20, as compared with the case where the magnetic field detection device 1 of the first embodiment does not have a convex portion.

  According to the magnetic field detection device 2B as the present modification, the magnetic field detection sensitivity in the Z-axis direction is lower than that of the magnetic field detection device 2A, but the degree of freedom of the installation location of the magnetic detection element 20 is increased. For example, it is possible to arrange a plurality of magnetic detection elements 20 around one convex portion 11P. In addition, since the flat surface 12S of the soft magnetic layer 12 as the base faces the respective magnetic detection elements 20, the magnetic flux density of the magnetic detection elements 20 between the plurality of magnetic detection elements 20 is reduced. It is easy to reduce variations and variations in detection sensitivity. Further, since the step of providing the convex portion 12P on the soft magnetic layer 12 is unnecessary, the manufacturing process of the magnetic field detecting device 2B is simplified as compared with the manufacturing process of the magnetic field detecting device 2A.

[2.4 Magnetic field detector 2C]
Next, a magnetic field detection device 2C as a third modification example of the second embodiment will be described with reference to FIG. FIG. 7 is a cross-sectional view showing an example of the overall configuration of the magnetic field detection device 2C. In the magnetic field detection device 2, the soft magnetic layer 11 is provided with the rectangular convex portion 11P and the soft magnetic layer 12 is provided with the rectangular convex portion 12P, but the present invention is not limited to this. .. In the magnetic field detection device 2C as the present modified example, the convex portions 11P and 12P having a substantially truncated cone shape with rounded tops are provided. Further, in this modification, a part of the convex portions 11P and 12P exists in the same layer as the layer including the magnetic detection element 20 that is substantially parallel to the XY plane.

  According to the magnetic field detection device 2C as the present modification, since the crowns of the protrusions 11P and 12P have a rounded shape, when detecting the external magnetic field component in the Z-axis direction, for example, the protrusions 11P and 12P. The spatial variation of the magnetic field strength around the parietal region of the is smoothed. Therefore, it can be expected that the detection error caused by the displacement of the arrangement positions of the plurality of magnetic detection elements 20 is alleviated.

[2.5 Magnetic field detector 2D]
Next, a magnetic field detection device 2D as a fourth modification example of the second embodiment will be described with reference to FIG. FIG. 8 is a sectional view showing an example of the overall configuration of the magnetic field detection device 2D. In the above magnetic field detection device 2A, the arrangement interval of the plurality of convex portions 11P provided on the soft magnetic layer 11 and the arrangement interval of the plurality of convex portions 12P provided on the soft magnetic layer 12 are substantially equal to each other. did. On the other hand, in the present modification, the arrangement interval of the plurality of convex portions 11P is different from the arrangement interval of the plurality of convex portions 12P. FIG. 8 illustrates the case where the array interval P11 of the plurality of convex portions 11P is longer than the array interval P12 of the plurality of convex portions 12P.

  According to the magnetic field detection device 2D as the present modification, the magnetic field detection sensitivities of the plurality of magnetic detection elements 20 are appropriately changed by changing the distances between the magnetic detection elements 20 and the convex portions 11P and the convex portions 12P. Can be adjusted.

<3. Experimental example>
[3.1 Experimental Examples 1-1 to 1-5]
Next, a magnetic field intensity distribution around the magnetic field detection device when an external magnetic field in the Y-axis direction was applied to the magnetic field detection device of the present invention (for example, the magnetic field detection device 1) was obtained by simulation. Here, in the soft magnetic layers 11 and 12, the dimension LX in the X-axis direction is 180 μm, the dimension LY in the Y-axis direction is 140 μm, and the thickness T is 10 μm. Further, the distance D between the soft magnetic layer 11 and the soft magnetic layer 12 was changed within the range of 10 μm to 150 μm. Specifically, the spacing D is 10 μm in Experimental Example 1-1, the spacing D is 20 μm in Experimental Example 1-2, the spacing D is 30 μm in Experimental Example 1-3, and the spacing D is 100 μm in Experimental Example 1-4. In Example 1-5, the distance D was set to 150 μm. The simulation results are shown in FIGS. 9A to 9E, respectively. As shown in FIGS. 9A to 9E, as the distance D (gap) between the soft magnetic layer 11 and the soft magnetic layer 12 is increased, the magnetic flux is generated in the space between the soft magnetic layer 11 and the soft magnetic layer 12. It was confirmed that was gradually entering. As shown in FIG. 9A, when the distance D is small, the soft magnetic layer 11 and the soft magnetic layer 12 exhibit an extremely high shielding effect, and the magnetic flux is generated between the soft magnetic layer 11 and the soft magnetic layer 12. Almost no entry into the space. On the other hand, it was confirmed that the magnetic flux gradually entered at the peripheral portions of the soft magnetic layer 11 and the soft magnetic layer 12 as the distance D increased (FIGS. 9B to 9E). However, it has been found that when the magnetic detection element is arranged in the space sandwiched by the soft magnetic layer 11 and the soft magnetic layer 12, a shield effect can be obtained for the external magnetic field in the Y-axis direction with respect to the magnetic detection element.

[3.2 Experimental Examples 2-1 and 2-2]
(Experimental example 2-1)
Next, a magnetic field strength distribution in the vicinity of the ends of the soft magnetic layers 11 and 12 when an external magnetic field in the Y-axis direction was applied to the magnetic field detection device of the present invention (for example, the magnetic field detection device 1) was obtained by simulation. .. Here, the thickness T of each of the soft magnetic layers 11 and 12 was set to 10 μm, and the distance D between the soft magnetic layer 11 and the soft magnetic layer 12 was changed in the range of 10 μm to 30 μm. The simulation results are shown in FIG.

(Experimental example 2-2)
Experimental Example 2 was repeated except that the thickness T of each of the soft magnetic layers 11 and 12 was set to 20 μm, and the distance D between the soft magnetic layer 11 and the soft magnetic layer 12 was set to 20 μm, 40 μm, or 60 μm. A simulation similar to that of -1 was performed. The result is shown in FIG.

  From the results shown in FIGS. 10 and 11, the penetration length LL from the edges of the soft magnetic layers 11 and 12 to the region where the magnetic field strength is substantially constant is approximately 1/2 of the distance D (that is, LL≈D / 2). I found out. Therefore, if the magnetic detection element 20 is arranged at a position retracted from the edges of the soft magnetic layers 11 and 12 by a length that is half the length corresponding to the distance D, more accurate magnetic field detection may be possible. all right.

[3.3 Experimental Examples 3-1 to 3-8]
Next, the critical magnetic field strength of the soft magnetic layers 11 and 12 when an external magnetic field in the Y-axis direction was applied to the magnetic field detection device of the present invention (for example, the magnetic field detection device 1) was obtained by simulation. Here, the thickness T of each of the soft magnetic layers 11 and 12 is 10 μm, the distance D between the soft magnetic layer 11 and the soft magnetic layer 12 is 10 μm, and the dimension LY of each of the soft magnetic layers 11 and 12 is 200 μm. The size LX of each of the soft magnetic layers 11 and 12 was changed in the range of 20 μm to 800 μm (that is, LX / LY = 0.1 to 4). The simulation results are shown in FIG.

  As shown in FIG. 12, it was confirmed that a higher critical magnetic field strength can be obtained when LX / LY is 1 or more and 4 or less as compared with the case where LX / LY is 1 or less.

<4. Other modifications>
Although the present invention has been described above with reference to some embodiments and modifications, the present invention is not limited to these embodiments and the like, and various modifications are possible. For example, in the present invention, the shape of the soft magnetic layer is not limited to that of the above-described embodiments and the like. For example, the planar shape is not limited to the rectangular shape, and various shapes can be adopted as shown in FIGS. 13A to 13D. Also in this case, it is desirable that the ratio between the maximum dimension b in the plane and the dimension a in the direction orthogonal to the direction having the maximum dimension b in the plane is within a predetermined range.

  Further, in the above-described embodiments and the like, the CPP MR element having the spin valve structure in which the magnetic sensing direction is the XY in-plane direction has been described as an example of the magnetic detection element, but the present invention is not limited to this. For example, a CIP (Current in Plane) type MR element or a magnetic tunnel junction (MTJ element) element may be used, or a magnetic detection element (for example, a Hall element) other than the MR element whose magnetic sensitive direction is the Z-axis direction, etc. You may use the sensor of. When a Hall element is used as the magnetic detection element, for example, as in the magnetic field detection device 3A and the magnetic field detection device 3B illustrated in FIGS. 14A and 14B, the positions overlapping the protrusions 11P and 12P (protrusions) in the Z-axis direction. That is, it is advisable to dispose the Hall element 20H directly above or directly below the protrusions 11P and 12P (protrusions).

  1, 2 ... Magnetic field detection device, 11, 12 ... Soft magnetic layer, 11P, 12P ... Convex portion, 20 ... Magnetic detection element, 21-24 ... Lead.

Claims (9)

A third surface that extends along a first surface that includes both a first direction and a second direction that is orthogonal to the first direction and that is orthogonal to both the first direction and the second direction. A first soft magnetic material and a second soft magnetic material that are arranged to face each other in the direction;
A magnetic field detection device comprising: a magnetic detection element provided between the first soft magnetic material and the second soft magnetic material in the third direction. The magnetic field detection device according to claim 1, wherein the following conditional expression (1) is satisfied in at least one of the first soft magnetic material and the second soft magnetic material.
1 ≦ LX / LY ≦ 4 (1)
However,
LX: dimension in the first direction LY: dimension in the second direction The magnetic field detection device according to claim 1, wherein the magnetic detection element is a magnetoresistive effect element. The first soft magnetic body includes a first facing surface facing the second soft magnetic body,
The second soft magnetic body includes a second facing surface facing the first soft magnetic body,
The first angle formed by the first straight line connecting the magnetic detection element and the edge of the first facing surface with respect to the first surface is 45 ° or less,
The second angle formed by the second straight line connecting the magnetic detection element and the edge of the second facing surface with respect to the first surface is 45 ° or less. The magnetic field detection device according to item 1. In the third direction, the position of the edge of the first facing surface and the position of the edge of the second facing surface substantially match,
The magnetic field detection device according to claim 4, wherein the following conditional expression (2) is satisfied.
L ≧ D / 2 (2)
However,
L: Distance between the edge of the first facing surface and the edge of the magnetic detection element in the direction along the first surface.
D: Distance between the first facing surface and the second facing surface. The first soft magnetic body includes a first facing surface facing the second soft magnetic body,
The second soft magnetic body includes a second facing surface facing the first soft magnetic body,
The magnetic field detection device according to claim 1, wherein one or more protrusions are formed on at least one of the first facing surface and the second facing surface. The magnetic field detection device according to claim 6, wherein a part of the protrusion part occupies a part of a layer including the magnetic detection element that is substantially parallel to the first surface. A first planar shape of the first soft magnetic body parallel to the first surface and a second planar shape of the second soft magnetic body parallel to the first surface are substantially equal. The magnetic field detection device according to any one of claims 1 to 7. The magnetic field detection device according to claim 2, wherein the second direction substantially coincides with a direction of an unnecessary magnetic field component other than the magnetic field component to be detected.

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