Magnetic sensor

Abstract

To provide a magnetic sensor capable of reducing a magnetic field detection area and improving spatial resolution.SOLUTION: A magnetic detection element 200 includes a nanogranular thin film 20, and a pair of light flux controlling members 210, 220 arranged to hold it therebetween in a thickness direction. Light projecting elements 111, 121 composing a plurality of optical units 110, 120 are caused to emit, to the nanogranular thin film 20, light adjusted to be polarized in a direction parallel to an incidence plane from different incident directions. On the basis a light reception amount of light transmitting through the nanogranular thin film 20 received by light receiving elements 1121, 1122, 1221, 1222, magnetic-field components HX, HY in respective directions parallel and perpendicular to the nanogranular thin film 20 are detected by a magnetic field detector 14.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a magnetic sensor that detects a magnetic field using the magneto-optical effect. [Background technology]

[0002] Magnetic sensors utilizing the magneto-optical effect have advantages over electrical measurement methods such as electromagnetic induction and semiconductors, including strong resistance to electrical noise and high insulation resistance. They have been proposed for use in rotation detection and current detection in power transmission and distribution equipment, railway equipment, and industrial machinery. Such magnetic sensors have been proposed that detect not only magnetic field strength in a specific direction, but also magnetic field strength and direction in unspecified directions (see Patent Document 1). According to this magnetic sensor, three sets of magneto-optical detection elements are configured to be orthogonal to each other. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 62-96875 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, according to this magnetic sensor, the three sets of magneto-optical elements, which are configured to be orthogonal to each other as described above, must be positioned so as not to interfere with the input and output light to each of them. As a result, the three magnetic field detection regions are placed far apart from each other, and the combined detection magnetic field region becomes large, resulting in a problem of inferior spatial resolution.

[0005] Therefore, the present invention aims to provide a magnetic sensor that can narrow the magnetic field detection area and, consequently, improve spatial resolution. [Means for solving the problem]

[0006] The magnetic sensor of the present invention is A magnetic detection element having a nanogranular thin film having a nanogranular structure in which metal nanoparticles are dispersed in a matrix, and a pair of light beam control members arranged so as to sandwich the nanogranular thin film in the thickness direction thereof, A plurality of optical units comprising a light-emitting element that incidents light, adjusted to be polarized in a direction parallel to the incident surface, onto the nanogranular thin film constituting the magnetic detection element via one of the pair of light-emitting elements, and a light-receiving element that receives the light transmitted through the nanogranular thin film via at least the other of the pair of light-emitting elements, A magnetic field detector that detects magnetic field components in directions parallel and perpendicular to the nanogranular thin film based on the amount of light received by each of the light-receiving elements constituting each of the plurality of optical units, Equipped with, The light-emitting elements constituting each of the plurality of optical units are arranged such that the direction of incidence of light onto the nanogranular thin film by each of the light-emitting elements constituting each of the plurality of optical units is different.

[0007] In this magnetic field sensor configuration, multiple beams of light are incident on a single nanogranular thin film from different directions by each light-emitting element constituting each optical unit. The magnetic field detection region in the nanogranular thin film is the region where the incident light intersects with the nanogranular thin film. Since the nanogranular thin film is a single unit, the regions where the incident light from each light-emitting element intersects with the nanogranular thin film are in a single plane, and the direction perpendicular to the plane of the nanogranular thin film in each intersection region is the same and equal to the film thickness direction. Therefore, each magnetic field detection region perpendicular to the plane of the nanogranular thin film is equal to the film thickness of the nanogranular thin film, enabling detection of a narrow magnetic field. Furthermore, since multiple beams of light can be incident on the same location on the nanogranular thin film, it is possible to roughly coincide multiple magnetic field detection regions, thereby narrowing the area of ​​the magnetic field detection region in the in-plane direction of the nanogranular thin film.

[0008] Furthermore, since it is possible to construct a magnetic detection element using a single nanogranular thin film, the structure of the magnetic detection element can be simplified, and manufacturing costs can be reduced.

[0009] Furthermore, the nanogranular thin film is sandwiched between a pair of light beam control members, and light is incident on the nanogranular thin film through the light beam control members. Therefore, by appropriately designing or selecting the refractive index of the light beam control members in accordance with the refractive index of the nanogranular thin film, the propagation angles of multiple beams of light propagating through the nanogranular thin film can be set to 45 degrees (2-axis detection) or 54.7 degrees (3-axis detection), which are symmetrical with respect to the normal to the main surface of the nanogranular thin film, so that each detection axis can be set in a Cartesian coordinate system. This makes it easy to calculate the direction and intensity of an externally applied magnetic field.

[0010] In the case of 3-axis detection, if the detection direction of each detection axis is configured to be a Cartesian coordinate system of the three axes, the directions of each detection axis can be expressed as <100>, <010>, and <001>. Here, if the direction perpendicular to the plane of the nanogranular thin film is the <111> direction, the angle between the direction of each detection axis and the direction perpendicular to the plane of the nanogranular thin film is 54.7 degrees. This is because in a cubic crystal system, the angle δ between plane (h1k1l1) and plane (h2k2l2) is cosδ = (h1h2 + k1k2 + l1l2) / ((h1 2 +k1 2 +l1 2 )(h2 2 +k2 2 +l2 2 )) 0.5 Therefore, if we set (h1k1l1) to (100), (010), or (001) and (h2k2l2) to (111), then cosδ = 1 / √3, which corresponds to finding δ = 54.7 deg.

[0011] Since a plurality of lights are incident on a single nanogranular thin film from different directions (directions inclined with respect to the main surface of the thin film), the change in the amount of light received by the light receiving element due to the change in the magnetic field depends on the polarization direction of the incident light. By adjusting the polarization direction of the light to be parallel to the light incident surface with respect to the nanogranular thin film, an increase in the amount of change in the amount of light received by the light receiving element is achieved, and thus an improvement in the magnetic field detection sensitivity is achieved. When the polarization direction of the light is adjusted to be parallel to the light incident surface with respect to the nanogranular thin film, it is preferable that the angle formed by the polarization direction of the light and the light incident surface with respect to the nanogranular thin film is included in the range of ±10 deg.

Brief Description of the Drawings

[0012] [Figure 1] Explanatory drawing regarding the configuration of a magnetic sensor as an embodiment of the present invention. [Figure 2] Explanatory drawing regarding the configuration of a magnetic detection element. [Figure 3] Explanatory drawing regarding the function of a light beam control member. [Figure 4A] Explanatory drawing regarding the correlation between the refractive index and the metal content ratio of a nanogranular thin film. [Figure 4B] Explanatory drawing regarding the correlation between the light propagation angle in a nanogranular thin film and the refractive index of a light beam control member. [Figure 4C] Explanatory drawing regarding the correlation between the light propagation angle in a nanogranular thin film and the refractive index of a light beam control member. [Figure 4D] Explanatory drawing regarding the correlation between the light propagation angle in a nanogranular thin film and the refractive index of a light beam control member. [Figure 5A] Explanatory drawing regarding the correlation between the amount of light received by a light receiving element and the angle of the magnetic field applied to a nanogranular thin film (φ = 0°). [Figure 5B] Explanatory drawing regarding the correlation between the amount of light received by a light receiving element and the angle of the magnetic field applied to a nanogranular thin film (φ = 90°). [Figure 5C] Explanatory drawing regarding the correlation between the amount of light received by a light receiving element and the angle of the magnetic field applied to a nanogranular thin film (φ = 45°). [Figure 6A] Explanatory diagram of the X - direction component Hx and Y - direction component Hy when an external magnetic field H is applied at an angle θ from the X - direction within the X - Y plane of the nanogranular thin film. [Figure 6B] Explanatory diagram of the X - direction component Mx = aHx and Y - direction component My = bHy of magnetization M according to the magnetic susceptibility a in the X - direction and magnetic susceptibility b in the Y - direction of the nanogranular thin film. [Figure 7] Explanatory diagram of the correlation between the detected magnetic - field component by the magnetic - detection element and the magnetic - field angle. [Figure 8] Explanatory diagram of the correlation between the output signal of the differential detector by the magnetic - detection element and the magnetic - field position.

Embodiments for Carrying Out the Invention

[0013] (Configuration of the magnetic sensor) As an embodiment of the magnetic sensor of the present invention shown in FIG. 1, it includes a laser 100 (for example, a semiconductor laser in the 1.55 - μm wavelength band), a first optical unit 110, a second optical unit 120, a magnetic - detection element 200, a first differential detector 11, a second differential detector 12, and a magnetic - field detector 14.

[0014] As shown in Figure 1, the first optical unit 110 comprises a first light-emitting element 111, a pair of first light-receiving elements 1121 and 1122, a polarizer 113, a 1 / 2λ plate 114, a lens 115, a 1 / 2λ plate 116, a polarizer 117, and a triangular prism 118. The first light-emitting element 111 projects one of the light beams emitted from the laser 100 and split via the coupler 102 onto the magnetic detection element 200 via the polarizer 113, the 1 / 2λ plate 114, and the lens 115. As a result, light polarized in a direction parallel to the incident surface is incident on the nanogranular thin film 20 constituting the magnetic detection element 200. The other first light-receiving element 1121 receives light from the magnetic detection element 200 via the lens 115, the 1 / 2λ plate 116, and the polarizer 117. The other first light-receiving element 1122 receives light from the magnetic detection element 200 via a triangular prism 118 in addition to the lens 115, 1 / 2λ plate 116, and polarizer 117.

[0015] Similarly, as shown in Figure 1, the second optical unit 120 includes a second light-emitting element 121, a pair of second light-receiving elements 1221 and 1222, a polarizer 123, a 1 / 2λ plate 124, a lens 125, a 1 / 2λ plate 126, a polarizer 127, and a triangular prism 128. The second light-emitting element 121 projects the other light emitted from the laser 100 and branched via the coupler 102 onto the magnetic detection element 200 via the polarizer 123, the 1 / 2λ plate 124, and the lens 125. As a result, light polarized in a direction parallel to the incident surface is incident on the nanogranular thin film 20 constituting the magnetic detection element 200. The other second light-receiving element 1221 receives light from the magnetic detection element 200 via the lens 125, the 1 / 2λ plate 126, and the polarizer 127. The other second light-receiving element 1222 receives light from the magnetic detection element 200 via a triangular prism 128 in addition to the lens 125, 1 / 2λ plate 126, and polarizer 127.

[0016] As shown in Figure 1, the first light-emitting element 111, which constitutes the first optical unit 110, and the second light-emitting element 121, which constitutes the second optical unit 120, are arranged such that the direction of light incidence to the nanogranular thin film 20 is different for each.

[0017] The first differential detector 11 (photodiode) outputs a signal corresponding to the amount of light received by each of the pair of first light-receiving elements 1121 and 1122 that constitute the first optical unit 110. The second differential detector 12 (photodiode) outputs a signal corresponding to the amount of light received by each of the pair of second light-receiving elements 1221 and 1222 that constitute the second optical unit 120. The signal processor 14 detects the magnetic field components in the X direction parallel to the nanogranular thin film 20 and the Y direction perpendicular to the nanogranular thin film 20 that constitutes the magnetic detection element 200, based on the output signals of the first differential detector 11 and the second differential detector 12.

[0018] As shown in Figure 2, the magnetic detection element 200 comprises a substrate 202, a nanogranular thin film 20 formed on the substrate 202, and a first light beam control member 210 and a second light beam control member 220 arranged to sandwich the nanogranular thin film 20 in its thickness direction.

[0019] The substrate 202 is, for example, a substantially rectangular member in the XZ plane with the Y direction as the thickness direction, and is made of a dielectric material having a refractive index of about the same magnitude as that of the first light beam control member 210. "About the same magnitude" means, for example, that the refractive index n of the substrate 202 is approximately equal to the refractive index n of the first light beam control member 210, such that the ratio (n / n1) of n to n1 of n1 of n1 falls within the range of 1 ± 0.13. For example, if n1 = 1.6, then n = 1.6 (n / n1 = 1.0) or n = 1.5 (n / n1 = 0.94).

[0020] The nanogranular thin film 20 has a nanogranular structure in which metal nanoparticles are dispersed in a matrix. The nanogranular thin film 20 has, for example, a composition represented by the general formula Fe a Co b Ni c M w N x O y F z (0 ≦ a ≦ 0.60, 0 ≦ b ≦ 0.60, 0 ≦ c ≦ 0.60, 0.05 < a + b + c < 0.60, 0.10 ≦ w ≦ 0.50, 0 ≦ x ≦ 0.50, 0 ≦ y ≦ 0.50, 0 ≦ z ≦ 0.50, 0.20 ≦ x + y + z ≦ 0.70, a + b + c + w + x + y + z = 1). The M component is at least one element selected from Mg, Al, Si, Ti, Y, Zr, Nb, Hf, and Ta. The metal nanoparticles are composed of at least one of Fe, Co, and Ni and have an average particle diameter of, for example, 2 to 50 nm. The matrix is composed of an insulator composed of the M component and at least one of N, O, and F. The thickness of the nanogranular thin film 20 is included in the range of, for example, 0.3 to 10 μm.

[0021] Each of the first light beam control member 210 and the second light beam control member 220 is composed of, for example, a substantially regular triangular prism-shaped dielectric member (e.g., glass (refractive index n1 = 1.60)) having the Z direction as the axial direction. As shown in FIG. 2, the first light beam control member 210 is joined or abutted to the substrate 202 on one of its side surfaces, and antireflection films 212 (e.g., composed of SiO2, Ta2O5, etc.) are formed on each of the other two side surfaces. As shown in FIG. 2, the second light beam control member 220 is joined or abutted to the nanogranular thin film 20 on one of its side surfaces, and reflection films 222 (e.g., composed of SiO2, Ta2O5, etc.) are formed on each of the other two side surfaces.

[0022] As shown in Figure 3, the first luminous beam control member 210 and the substrate 202 are made of a material having a suitable refractive index n1 to control the angle of refraction θ2 (propagation angle) of light incident on the nanogranular thin film 20 having refractive index n2 at an incident angle θ1, via the first luminous beam control member 210 and the substrate 202. Similarly, the second luminous beam control member 220 is made of a material having a suitable refractive index n1 to control the angle of refraction θ2 (propagation angle) of light incident on the nanogranular thin film 20 having refractive index n2 at an incident angle θ1, via the second luminous beam control member 220.

[0023] Figure 4A shows the correlation between the refractive index n2 of a nanogranular thin film 20, in which metal nanoparticles are composed of Fe and Co and the matrix is ​​composed of Mg fluoride, and the Fe and Co content (mol%). From Figure 4A, it can be seen that the refractive index n2 of the nanogranular thin film 20 increases as the Fe and Co content increases.

[0024] Figure 4B shows the correlation between the angle of incidence θ1 and the angle of refraction θ2 of light to the nanogranular thin film 20 when the refractive index n1 of the first light beam control member 210 (and substrate 202) is 1.6, and the refractive index n2 of the nanogranular thin film 20 is 1.6, 1.8, 2.0, 2.4, and 2.8, respectively, indicated by solid, dotted, dashed, double-dashed, and broken lines, respectively.

[0025] Figure 4B shows that when the refractive index n1 of the first luminous flux control member 210 (and substrate 202) and the second luminous flux control member 220 is designed to be 1.6, adjusting the incident angle θ1 to 60 degrees adjusts the refraction angle θ2 (propagation angle) in the nanogranular thin film 20 with a refractive index n2 of 2.0 to 45 degrees. In this case, adjusting the incident angle θ1 to 65 degrees adjusts the refraction angle θ2 (propagation angle) in the nanogranular thin film 20 with a refractive index n2 of 1.8 to 55 degrees. Furthermore, when the refractive index n2 is 2.0, 2.4, or 2.8, it can be seen that the refraction angle θ2 (propagation angle) in the nanogranular thin film 20 cannot be adjusted to 55 degrees even by adjusting the incident angle θ1.

[0026] On the other hand, as shown in Figure 4C, if the first luminous flux control member 210 and the second luminous flux control member are not present, even if the refractive index n2 of the nanogranular thin film 20 is designed to be 1.6, its refraction angle θ2 (propagation angle) will only be about 38 degrees.

[0027] Figure 4D shows the correlation between the angle of incidence θ1 and the angle of refraction θ2 of light to the nanogranular thin film 20, when the refractive index n1 of the first light beam control member 210 is 1.6, the refractive index n of the substrate 202 is 1.5, and the refractive index n2 of the nanogranular thin film 20 is 1.6, 1.8, 2.0, 2.4, and 2.8, respectively, indicated by solid, dotted, dashed, double-dashed, and broken lines, respectively. In Figure 4D, since the refractive index of the substrate 202 is smaller than that of the first light beam control member 210, if the incident angle θ1 is 70 degrees or more, the incident light is totally reflected at the boundary between the first light beam control member 210 and the substrate 202. Therefore, the allowable incident angle θ1 is less than 70 degrees. However, if the refractive index n2 of the nanogranular thin film 20 is 1.8, the refraction angle θ2 (propagation angle) can be adjusted to 55 degrees when the incident angle θ1 is 67 degrees, and the refraction angle θ2 (propagation angle) can be adjusted to 45 degrees when the incident angle θ1 is 53 degrees. Furthermore, if the refractive index n2 of the nanogranular thin film 20 is 2.0, the refraction angle θ2 (propagation angle) can be adjusted to 45 degrees when the incident angle θ1 is 62 degrees.

[0028] (Function of magnetic sensor) A magnetic field H forming an angle θ with respect to the Y direction (a direction perpendicular to the nanogranular thin film 20) was applied to the nanogranular thin film 20. In this state, when light with an incident plane of the XY plane and a refraction angle θ2 (propagation angle) of +45° was incident on the nanogranular thin film 20 by the first light-emitting element 111, the correlation between the amount of light received by the first light-receiving elements 1121 and 1122 and the angle θ was measured. Also in this state, when light with an incident plane of the XY plane and a refraction angle θ2 (propagation angle) of -45° (a direction forming a 90° angle with respect to the incident angle of light by the first light-emitting element 111) was incident on the nanogranular thin film 20 by the second light-emitting element 121, the correlation between the amount of light received by the second light-receiving elements 1221 and 1222 and the angle θ was measured.

[0029] Figure 5A shows the correlation between the amount of light received by one of the first light-receiving elements 1121 and the magnetic field angle θ when the angle φ between the incident plane and the polarization plane for the nanogranular thin film 20 is 0° (the incident plane and the polarization plane are parallel), indicated by a dashed line, and the correlation between the amount of light received by the other first light-receiving element 1122 and the magnetic field angle θ indicated by a double dashed line. Figure 5B shows the correlation between the amount of light received by one of the first light-receiving elements 1121 and the magnetic field angle θ when the angle φ between the incident plane and the polarization plane for the nanogranular thin film 20 is 90° (the incident plane and the polarization plane are perpendicular), indicated by a dashed line, and the correlation between the amount of light received by the other first light-receiving element 1122 and the magnetic field angle θ indicated by a double dashed line. Figure 5C shows the correlation between the amount of light received by one of the first light-receiving elements 1121 and the magnetic field angle θ when the angle φ between the incident plane and the polarization plane for the nanogranular thin film 20 is 45°, with a dashed line, and the correlation between the amount of light received by the other first light-receiving element 1122 and the magnetic field angle θ is shown with a double dashed line.

[0030] Figures 5A to 5C show that when the angle φ between the incident plane and the polarization plane for the nanogranular thin film 20 is 0° (when the incident plane and the polarization plane are parallel), the amount of light received by the first light-receiving element 1121 is maximum, and the magnetic detection sensitivity is highest. The same applies to the second light-receiving elements 1221 and 1222 of the second optical unit 120, although the explanation is omitted.

[0031] The magneto-optical effect of the nanogranular thin film 20 is proportional to the magnitude of the magnetization M with respect to the external magnetic field H. However, due to the effect of the shape of the nanogranular thin film 20, the magnetic susceptibility perpendicular to the surface and the magnetic susceptibility parallel to the surface differ due to the effect of the demagnetizing field. Therefore, in order to determine the external magnetic field H from the measured quantity corresponding to the magnetization M obtained from the magneto-optical effect, it is necessary to correct for the effect of the demagnetizing field.

[0032] Figure 6A shows the X-direction component Hx and the Y-direction component Hy when an external magnetic field H is applied to the nanogranular thin film 20 in the XY plane at an angle θ from the X direction.

[0033] In this case, the magnetization M of the nanogranular thin film 20 is a combined value of Mx = aHx and My = bHy, as shown in Figure 6B, where a is the magnetic susceptibility in the direction parallel to the surface (X direction) and b is the magnetic susceptibility in the direction perpendicular to the surface (Y direction). On the other hand, the P and Q directions, which are the directions of light propagation, are the directions in which the magnetization M is detected due to the magneto-optical effect. Therefore, the magneto-optical effect, which is proportional to the magnetization components Mp and Mq in the P and Q directions, respectively, is detected by the first differential detector 11 and the second differential detector 12, respectively. The relationship between the magnetization components Mp and Mq and the magnetic field components Hx and Hy is expressed by the following relation (11) using the angle α between the P and X directions and the angle β between the Q and Y directions. Therefore, by measuring the magnetic susceptibility a and b in advance, the magnetic field components Hx and Hy can be determined according to this relation.

[0034] aHx = Mp × cosα - Mq × sinβ, bHy=Mq×cosβ+Mp×sinα‥(11).

[0035] If we set α=β=45deg, then relation (11) can be simplified to the following equation (12).

[0036] aHx = (1 / 2) 1 / 2 ×(Mp-Mq), bHy = (1 / 2) 1 / 2 ×(Mq+Mp) ‥(12).

[0037] A magnetic field H forming an angle θ with respect to the Y direction (a direction perpendicular to the nanogranular thin film 20) was applied to the nanogranular thin film 20 by a magnet. In this state, the first light-emitting element 111 incident light on the nanogranular thin film 20 with a refraction angle θ2 (propagation angle) = +45° and the XY plane as both the incident plane and the plane of polarization, and the second light-emitting element 121 incident light on the nanogranular thin film 20 with a refraction angle θ2 (propagation angle) = -45° and the XY plane as both the incident plane and the plane of polarization. Then, based on the amount of light received by the first light-receiving elements 1121 and 1122 and the amount of light received by the second light-receiving elements 1221 and 1222, the magnetic detector 14 detected a magnetic field component H parallel to the nanogranular thin film 20. X and the perpendicular magnetic field component H Y Each of these was measured.

[0038] Figure 7 shows the correlation between the magnetic field components Hx and Hy, respectively, and the angle θ of the magnetic field H, indicated by the dashed-dotted and single-dotted lines, respectively. From Figure 7, it can be seen that the magnetic field component Hx in the X direction is maximized at magnetic field orientation θ of 90deg and 270deg, and the magnetic field component Hy in the Y direction is maximized at magnetic field orientation θ of 0deg (360deg) and 180deg, indicating that the magnetic field components due to the magnet are being measured correctly.

[0039] A magnet was used to apply a magnetic field H to the nanogranular thin film 20 in the X direction (parallel to the nanogranular thin film 20), while the position of the magnet was displaced in the +X and -X directions, and the magnet was rotated 360 degrees at each position in the X direction. In this state, the first light-emitting element 111 incident light on the nanogranular thin film 20 with a refraction angle θ2 (propagation angle) = +45° and the XY plane as both the incident plane and the plane of polarization, and the second light-emitting element 121 incident light on the nanogranular thin film 20 with a refraction angle θ2 (propagation angle) = -45° and the XY plane as both the incident plane and the plane of polarization. Based on the amount of light received by the first light-receiving elements 1121 and 1122 and the amount of light received by the second light-receiving elements 1221 and 1222, the output signals due to the magneto-optical effect, which are proportional to the magnetization component, were measured by the first differential detector 11 and the second differential detector 12.

[0040] Figure 8 shows the correlation between the maximum amplitude of the output signal obtained by the magneto-optical effect, which is proportional to the magnetization component and detected by the first differential detector 11 and the second differential detector 12, when the magnet is rotated 360 degrees, and the position X of the magnet, for each position in the X direction, indicated by dashed and double-dotted lines, respectively. From Figure 8, it can be seen that for both the output signal of the first differential detector 11 based on the amount of light received by the first light receiving elements 1121 and 1122, and the output signal of the second differential detector 12 based on the amount of light received by the second light receiving elements 1221 and 1222, the X position where the maximum amplitude is obtained is approximately X=0, indicating that the magnetic field detection position of the first optical unit 110 and the magnetic field detection position of the second optical unit 120 are approximately the same, and that the magnetic field detection regions are the same. [Explanation of Symbols]

[0041] 11...First differential detector, 12...Second differential detector, 14...Magnetic field detector, 20...Nanogranular thin film, 100...Laser (light source), 110...First optical unit, 111...First light-emitting element, 1121, 1122...First light-receiving element, 120...Second optical unit, 121...Second light-emitting element, 1221, 1222...Second light-receiving element, 200...Magnetic detection element, 202...Substrate, 210...First light beam control member, 212...Anti-reflective film, 220...Second light beam control member, 222...Reflective film.

Claims

[Claim 1] A magnetic detection element having a nanogranular thin film having a nanogranular structure in which metal nanoparticles are dispersed in a matrix, and a pair of light beam control members arranged so as to sandwich the nanogranular thin film in the thickness direction thereof, A plurality of optical units comprising a light-emitting element that incidents light, adjusted to be polarized in a direction parallel to the incident surface, onto the nanogranular thin film constituting the magnetic detection element via one of the pair of light-emitting elements, and a light-receiving element that receives the light transmitted through the nanogranular thin film via at least the other of the pair of light-emitting elements, A magnetic field detector that detects magnetic field components in directions parallel and perpendicular to the nanogranular thin film based on the amount of light received by each of the light-receiving elements constituting each of the plurality of optical units, Equipped with, The light-emitting elements constituting each of the plurality of optical units are arranged such that the direction of light incidence to the nanogranular thin film by each of the light-emitting elements constituting each of the plurality of optical units is different. Magnetic sensor.

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